Strategies for treating melanoma subtypes - Acral, Mucosal, Uveal, Nodular, Lentigo

 

While melanoma, despite the huge improvements made when targeted and immunotherapies gained FDA approved in 2011 remains a very difficult cancer to treat and survive, the subtypes noted in the title make cutaneous melanoma look like a walk in the park.  This LINK takes you to reports on those subtypes that I have previously posted.  The link below takes you to a pretty thorough report addressing these particular forms of melanoma as well as a good history regarding BRAF status.  I have included much of the report below.  Words are from the authors - not me.  However, checking out the link is valuable, as it includes tables and references not reported here.

Emerging strategies to treat rare and intractable subtypes of melanoma. Gretchen and Vito. Pigment Cell Melanoma Res. Jan 2021.

Melanoma is the deadliest form of skin cancer, possessing a diverse landscape of subtypes with distinct molecular signatures and levels of aggressiveness. Although immense progress has been achieved therapeutically for patients with the most common forms of this disease, little is known of how to effectively treat patients with rarer subtypes of melanoma. These subtypes include acral lentiginous (the rarest form of cutaneous melanoma; AL), uveal, and mucosal melanomas, which display variations in distribution across (a) the world, (b) patient age-groups, and (c) anatomic sites. Unfortunately, patients with these relatively rare subtypes of melanoma typically respond worse to therapies approved for the more common, non-AL cutaneous melanoma and do not have effective alternatives, and thus consequently have worse overall survival rates. Achieving durable therapeutic responses in these high-risk melanoma subtypes represents one of the greatest challenges of the field. This review aims to collate and highlight effective preclinical and/or clinical strategies against these rare forms of melanoma.

INTRO - 

The melanoma field represents a paradigm for preclinical and clinical advancements in targeted and immune therapy modalities, with 13 new FDA-approved therapies since 2011. The catalyst for the development of targeted therapy modalities was the identification of activating NRAS mutations and BRAF mutations in 1984 and 2002... which paved the way for molecular stratification of the melanoma patient population. Approximately 45%–50% of non-acral lentiginous (AL) cutaneous melanoma patients have tumors that harbor activating BRAF mutations, with a single amino acid substitution of valine for glutamic acid at codon 600 (V600E) occurring in 90% of cases. Activating NRAS mutations at codon 12, 13, or 61 are detectable in 15%–20% of non-AL cutaneous melanoma patients and serve as an independent predictor of worse patient overall survival. Mutations of BRAF and NRAS are considered mutually exclusive; however, there are rare reports where both mutations exist in different regions of the same tumor or at different metastatic sites of the same patient. To date, it remains unclear whether the same melanoma cell can harbor both a BRAF and an NRAS mutation, or at the single-cell level, these mutations are indeed mutually exclusive.

With discoveries revealing that ~70% of non-AL cutaneous melanomas contain mutations constitutively activating the mitogen-activated protein kinase (MAPK) pathway came intense development of inhibitors capable of targeting various nodes of the mitogen-activated protein kinase (MAPK) pathway (i.e., BRAF, MEK, and ERK inhibitors) that continues to date. The first targeted therapy approved for the treatment of patients with BRAFV600E/K mutant melanoma was the small molecule inhibitor vemurafenib, an agent designed to have high specificity against the mutant V600E, V600K, V600D, and V600R forms of BRAF. Vemurafenib had response rates of ~48% in phase II and III clinical trials leading to the 2011 Food Drug and Agriculture (FDA) approval. A few years later, the combination of a BRAF inhibitor and a MEK inhibitor was observed to further increase the response rate to ~76% leading to the 2014 FDA approval of dabrafenib and trametinib. There are now three BRAF inhibitor plus MEK inhibitor combinations FDA approved for melanoma patients with BRAFV600E/K mutations (dabrafenib/trametinib, vemurafenib/cobimetinib, and encorafenib/binimetinib.

For patients with wild-type BRAF, treatment with BRAF inhibitors that specifically target V600E/K mutant BRAF may increase melanoma aggressiveness due to the paradoxical activation of wild-type BRAF and downstream MAPK pathway signaling. Preclinically, targeting downstream of BRAF with MEK inhibitors in BRAF-wild-type melanoma cells demonstrates the importance of the MAPK pathway for their survival, with significant anticancer activity. However, clinical trials testing multiple MEK inhibitors (i.e., binimetinib, trametinib) have concluded that although encouraging response rates and small increases in progression-free survival could be achieved in certain trials relative to dacarbazine, no significant increase in overall survival of patients with BRAF-wild-type melanoma was achieved with MEK inhibition. In an effort to increase MEK inhibitor efficacy, combination strategies with other agents (i.e., PI3K inhibitors, CDK4/6 inhibitors) are being clinically tested in the BRAF-wild-type (i.e., patients with or without NRAS-MT melanoma) setting after failure of immunotherapy. ERK inhibitors are also being clinically investigated to see if durable efficacy can be achieved in patients with wild-type BRAF, with reports showing the first-in-class ERK1/2 inhibitor ulixertinib has an acceptable safety profile and early evidence of clinical activity. Preclinical evidence suggests that concurrent inhibition of multiple nodes of the MAPK pathway in NRAS-mutant melanoma (i.e., MEK and ERK) may have synergistic activity on par with the BRAF inhibitor and MEK inhibitor combination in BRAF-mutant melanomas, and further studies evaluating this strategy are under way.

In parallel, large strides have been made in the development of immune checkpoint blockade strategies with the FDA approval of antibodies targeting cytotoxic T-lymphocyte antigen 4 (CTLA4, ipilimumab) in 2011 and programmed cell death 1 (PD1, pembrolizumab, nivolumab) in 2014  and the combination of ipilimumab and nivolumab in 2015. Immune checkpoint blockade describes the use of therapeutic antibodies that overcome immunosuppressive checkpoints with the goal of unchaining antitumor immune responses. CTLA4 and PD-1 are both receptors that suppress effector T-cell activity. These immunotherapy-based strategies elicit long-lasting responses in a subset of patients and represent a therapeutic strategy suitable for all genotypes of non-AL cutaneous melanoma. However, the majority of patients treated with immunotherapy progress within 5 years due to poorly understood primary resistance mechanisms, and clinicians still cannot reliably discriminate which patients will respond or not respond. Both tumor intrinsic (i.e., insufficient tumor antigenicity, tumor interferon-γ signaling, tumor stemness) and extrinsic (i.e., regulatory T cells, myeloid-derived suppressor cells) resistance mechanisms have been reported, and there are intense efforts focused on overcoming these therapeutic hurdles to further increase the efficacy of immune checkpoint blockade strategies.

The promising efficacy of these new therapeutic strategies has been demonstrated largely in non-AL cutaneous melanoma patients with either superficial spreading melanoma (SSM), nodular melanoma (NM), or lentigo maligna melanoma (LMM). SSM, NM, and LMM represent the most common forms of melanoma in Caucasians (>85% of cases). It is important to appreciate that most of the recent pivotal discoveries in melanoma were performed on SSM cell lines, short-term cultures, animal models, and tumor biopsies taken from patients with SSM largely due to their greater availability. AL melanoma represents the fourth and rarest subtype of cutaneous melanoma. In addition, mucosal melanoma and uveal melanoma are other rare subtypes of melanoma that are non-cutaneous in origin. The efficacy of immune checkpoint blockade is lower in rarer subtypes of melanoma relative to patients with non-AL cutaneous melanoma, which will be discussed later. There is also little information regarding the efficacy of combination BRAF inhibitor and MEK inhibitor therapy in these subtypes. 

Acral - 

Acral lentiginous melanoma is an uncommon yet relatively aggressive subtype of CMM that accounts for 2%–3% of all melanoma cases. AL melanoma arises on sun-protected, glabrous skin of the soles, palms, and nail beds. AL melanoma has been historically associated with worse 10-year survival rates relative to other forms of CMM (67.5% vs. 87.5%). Further, 10-year AL melanoma survival rates are highest in non-Hispanic Whites (69.4%), intermediate in Blacks (71.5%), and lowest in Hispanic Whites (57.3%) and Asian/Pacific Islanders (54.1%), as found by the Surveillance, Epidemiology, and End Results (SEER) Program of the National Cancer Institute evaluating data from 17 population-based cancer registries from 1986 to 2005. Another analysis of AL melanoma prognostic features in a cohort of German, Swiss, and Austrian patients suggests no significant difference exist relative to other subtypes of cutaneous melanoma; however, this conclusion may stem due to differential ethnicity landscapes between this patient cohort and that in the SEER study. There does not appear to be a gender bias, with a similar frequency between men and women and a comparable median age of diagnosis of 63.1 years for men and 62.2 years for women. The incidence of AL melanoma increases with age, and for reasons poorly understood, men are twice as likely to develop AL melanoma relative to women after the age of 80.

The distribution of AL melanoma varies geographically among populations throughout the world. While AL melanoma represents only ~2%–3% of all melanoma cases in Caucasian populations, AL melanoma makes up 50%–80% of all cases in non-Caucasian individuals in the United States (i.e., those of African, Latin American, and Asian descent). Furthermore, the incidence in Hispanic Whites doubles compared to non-Hispanic Whites after the aged of 70. A 2009 SEER study found the overall incidence rates of AL melanoma were similar between non-Hispanic Whites and Blacks; however, Hispanic Whites have statistically higher incidence rates relative to non-Hispanic Whites . Updated epidemiological studies should be performed to continue understanding the differential incidence trends that may exist across different ethnicities. Of note, the incidence of other subtypes of cutaneous melanoma (i.e., NM, SSM) is much lower in non-Caucasians relative to Caucasians. As this subtype of melanoma is not related to ultraviolet radiation (UV), there are different theories of the cause of AL melanoma. Some reports state that trauma and pressure in the foot (a predilected area of AL) is causal. However, the hand is also exposed to trauma but its location is less favorable. The main sites of AL melanoma metastases are the lungs, distant lymph nodes, scalp, contralateral limb, and liver.

Acral lentiginous melanomas possess a significantly lower mutational burden relative to the more common cutaneous melanoma subtypes, likely due to the sun-protected locations they arise from. BRAF mutations in are found in 1 in every 5 Al melanoma patients, leaving ~80% ineligible to receive BRAF inhibitor and combination BRAF/MEK inhibitor strategies . Therefore, new targets specific for AL melanoma are needed. 80% of AL melanomas display genetic aberrations of cyclin-dependent kinase 4/6 (CDK4/6) pathway-related genes (i.e., amplification of CDK4 and CCND1, and/or loss of CDK2NA), representing the most frequent copy number alteration detected . Additionally, activating KIT mutations are present in ~6% of cases. AL melanoma displays similar incidence of NRAS mutations as non-AL cutaneous melanoma, detectable in 15%–28% of AL melanoma patients, and NRAS mutations are an independent prognostic factor of worse overall survival.

Considerable barriers exist to treat patients with AL melanoma: (a) a contrasting genomic and genetic landscape relative to non-AL cutaneous melanomas, (b) unclear targetable drivers, and (3) sparse experimental models available for preclinical drug development. Unfortunately, FDA-approved targeted therapy strategies for melanoma are not available for the majority of AL melanoma patients (i.e., BRAF inhibitors since AL melanoma has a low frequency of BRAF mutations), and the efficacy of immune checkpoint blockade strategies is not well known in AL melanoma, with differing overall response rates (ORR) differing by country. For example, the ORR of anti-PD-1 in AL melanoma patients was found to be similar to that in non-AL cutaneous melanoma patients within the United States. In contrast, the ORR was 66.7% for SSM patients and 28.6% of AL melanoma patients in a recent Japanese study, suggesting the efficacy of immune checkpoint blockade may vary with ethnicity. The lower mutational burden observed in AL melanoma cases is thought to drive the reduced efficacy of immune checkpoint inhibitor strategies (e.g., PD-1 blockade) in patients. Although AL melanoma patients with Kit mutations can be treated with a KIT inhibitor per National Comprehensive Cancer Network (NCCN) guidelines, resistance mechanisms that reactivate downstream MAPK and PI3K pathway signaling have been suggested to blunt long-term durability. Due to the high percentage of AL melanoma tumors with CDK4/6-pathway aberrations, CDK4/6 inhibition represents one of the most promising targeted therapy strategies for AL melanomas clinically. However, durable responses are not observed in all patients due to resistance and CDK4/6 inhibitor-based combinations will likely be needed to improve the curative rate for patients with AL melanoma. Preclinical investigation to optimize targeted therapy strategies has not been extensively performed in AL melanoma models, but the rich body of literature that exists from studies in non-AL cutaneous melanoma models strongly suggests that single-agent approaches will not be durable due to the nearly universal onset of resistance. In SSM models, treatment with a MAPK pathway inhibitor plus a CDK4/6 inhibitor has shown synergistic activity in BRAF-MT and BRAF-wild-type settings; however, residual disease persists. Resistance mechanisms to CDK4/6 inhibitors and/or MEK inhibitors must be delineated to develop combination strategies that produce durable responses in AL melanoma patients.

Mucosal Melanoma - 

Mucosal melanoma (MM) is one of the rarest types of melanoma, accounting for only 1% of all cases, and has a significantly worse prognosis relative to the other subtypes. Distinct from cutaneous melanoma, MM arises from melanocytes located in mucosal membranes inside the body (i.e., genitourinary, anorectal, nasopharyngeal). The head and neck (55), vulva (18), and anus (24) are the most common observed sites; however, MM can also occur in the gut, lungs, and urinary track. It is rarely diagnosed at early stages due to difficult visual detection, which is much more tractable for cutaneous subtypes of melanoma. The overall median age of diagnosis is 70 years, with the exception of MMs arising in the mouth that manifest more frequently in younger patients. The incidence of MM has been stable for the last few years with the exception of MM in the genital tract, which is higher in females relative to males for reasons not clearly understood.

Approximately 3%–15% of MMs harbor an activating mutation in BRAF, with ~63% located on the V600 codon and 37% located on a non-V600 codon. This is in contrast to non-AL cutaneous melanomas where <10% of BRAF mutations are outside of the V600 codon, and more closely resembles the high prevalence of non-V600 mutations found in 48% of lung adenocarcinomas. A closer analysis of the most common non-V600 mutations reveals (a) a difference between the frequency of mutations on D594, G469, and K601 between non-AL cutaneous melanomas and MMs, and (b) convergence in the non-V600 mutational landscape between MM and lung cancers where mutations are often associated with genotoxic agents.

In regard to NRAS mutations, approximately 12% of MMs harbor activating mutations, which is lower relative to cutaneous melanomas where NRAS mutations occur in 15%–20% of cases. There is also a divergence in the location of NRAS mutations between MM and cutaneous melanoma, with 54% located on codon 61 in MM versus 88% in cutaneous melanoma, and 46% located on codons 12 and 13 in MM versus 12% for cutaneous melanomas. Approximately 7%–22% of MMs have v-kit Hardy-Zuckerman 4 feline sarcoma viral oncogene homolog (KIT) somatic mutations or amplifications. MMs located in the genital area appear to be driven by mutations in SF3B1 which encodes the subunit 1 of splicing factor 3b, a component of the spliceosome that processes pre-mRNA into mature transcripts. A recent study analyzing the mutational landscape of MM identified IGF2R mutations in 31.7% of MM samples relative to 6.3% of SSM cases. Interestingly, a lower frequency of UV-induced DNA damage, a lower number of mutations and a link to high tobacco exposure have also been identified in MM.

Unfortunately, MM is typically detected at relatively more advanced states due to difficulty in early detection. The main treatment for MM differs slightly on where the tumor is located; however, like any other subtype of melanoma, patients are initially treated with surgical excision. MMs arising in the head and neck are treated with complete surgical excision of the tumor when the patient is in stages III and IVA. However, this is associated with a high rate of recurrence. MMs that have arisen in the vulvovaginal or anorectal area also receive radiation in addition to surgical tumor excision. Therapeutic efficacy may be improved in select patients when treatment is personalized by tumor mutational status. Clinical trials targeting KIT with imatinib show no clear effect in unselected metastatic melanoma patient populations, but encouraging clinical benefit has been observed with KIT inhibition specifically in patients with melanomas harboring KIT mutations (not in patients whose melanoma harbor KIT amplification only). Nonetheless, disease progression ultimately occurs in the majority of cases. These data support the practice of determining KIT mutational status for MM patients to have a higher chance of receiving additional clinical benefi. Subsequent phase II clinical trials now require a KIT alteration for enrollment. For the relatively small number of MM patients whose tumors harbor BRAF mutations (relative to the ~50% in non-AL cutaneous melanoma patients), treatment with combination BRAF inhibitor and MEK inhibitor therapy is available. However, the efficacy of targeted therapy specifically in the MM patient population is not completely understood due to the low number available for analysis.

The efficacy of immune checkpoint inhibitor therapy also remains unclear in MM patients, with conflicting evidence of whether MM patients respond as well as non-AL cutaneous melanoma patients. In one multi-institutional analysis of clinical trials focusing on all the subtypes of metastatic melanoma, patients with MM had similar responses compared with non-AL cutaneous melanoma patients when treated with anti-PD-1 single-agent therapy, with a progression-free survival of 3.9 months . In another pooled analysis, MM patients treated with nivolumab as monotherapy or nivolumab in combination with ipilimumab experienced reduced clinical benefit relative to non-AL cutaneous melanoma patients. MM patients experienced 50% shorter progression-free survival (3.0 months) relative to patients with non-AL cutaneous melanoma (6.2 months) for monotherapy (nivolumab) and for nivolumab plus ipilimumab (5.9 vs. 11.7 months. Another recent study combining axitinib (small molecule receptor tyrosine kinase inhibitor) with toripalimab (anti-PD-1) found a median progression-free survival of 7.5 months in among 29 patients with chemotherapy-naïve mucosal melanoma. Although these data suggest that MM patients may not achieve as much benefit with immune checkpoint inhibitor therapy as non-AL cutaneous melanoma patients, it should be considered that in each of the pooled analyses, the number of MM cases was only 10% of patients compared to 75% from cutaneous melanoma. Also notable, another prospective study where 44 patients with unresectable MM were treated with immune checkpoint inhibitors concluded that the site of origin for MM (i.e., vaginal, anal) may not have a significant impact on the objective response rate, which was 8.2% for ipilimumab and 35% for pembrolizumab. The lower mutational burden in MM relative to non-AL cutaneous melanoma may explain the decreased efficacy of immune checkpoint blockade in MM.

Uveal Melanoma -

Uveal melanoma (UM) is the most common form of ocular melanoma, as well as the most prevalent form of non-cutaneous melanoma, accounting for 5% of all melanomas . It most commonly arises in non-Hispanic Whites relative to other races (i.e., African and Asian Americans), with a slight predominance for men (52.3%) relative to women (47.7%). The incidence of UM has remained stable over the last few decades and is diagnosed in 4–5 per million individuals in the United States each year. The median age of diagnosis is 62, and the incidence of UM increases with age. Early detection of UM provides a favorable 85% survival rate; however, this survival rate significantly decreases to 15% once UM cells have disseminated. Approximately 50% of UM patients develop metastases, and among patients with metastatic disease, 90% have liver involvement and ~70% have liver-only disease. This is a distinct metastatic pattern relative to cutaneous melanoma or mucosal melanoma.

Unlike non-AL cutaneous melanomas, UMs have a much lower mutational burden due to the sun-protected site they arise from within the ocular cavity. Activating mutations in BRAF or NRAS are not detected (extremely rare) in tumor cells of UM patients. In contrast, the main drivers for UM are activating mutations of guanine nucleotide-binding protein G (GNAQ/11), splicing factor 3B subunit 1 (SF3B1), eukaryotic translation initiation factor (EIF1AX), and inactivating mutations of the tumor suppressor BRCA-associated protein-1 (BAP1). The GNAQ/11 genes encode specific GTP binding proteins that mediate signal transduction from the inner cell surface to the MAPK pathway through activation of the protein kinase C (PKC) enzyme. GNAQ and GNA11 mutations are mutually exclusive, and thus in total are detected in 85%–94% of UM across all stages of disease. Due to their detection in benign uveal nevi, GNAQ/11 mutations are thought to be early mutational events.

BAP1 (located on the short arm of chromosome 3) loss-of-function mutations are posited to serve as a predisposing factor for diverse hereditary cancers including mesothelioma, cutaneous melanoma, renal cell carcinoma, and UM. A recent comprehensive review identified that among 174 patients harboring germline BAP1 mutations, 130 developed tumors that were either UM (31% of cases), cutaneous melanoma (13% of cases), renal cell carcinoma (10% of cases), or MM (22% of cases). In UM, loss of BAP1 returns melanoma cells to a more stem cell-like state as BAP1 is involved in melanocyte differentiation. BAP1 is frequently mutated in metastasizing uveal melanomas, which supports the growing evidence that stem-like melanoma cell states drive elements of the metastatic cascade.

There has been a recent decline in UM patients treated solely with surgery due to micrometastases that develop years before primary tumor detection. The current approach for treatment of metastatic UM is radiation; however, the survival rate is not significantly improved relative to what is possible from surgery. There have been an array of clinical studies trying to identify efficacious therapeutic strategies for patients with metastatic UM. UM patients that possess GNAQ or GNA11 mutations can be treated in clinical trials with targeted therapy approaches specific for the MAPK pathway (i.e., MEK inhibitor, ERK inhibitor) as these tumors display elevated MAPK activity. Preclinical studies have shown that treatment of UM with a combination of a MAPK pathway inhibitor and a PKC inhibitor may provide synergistic efficacy relative to what is achievable by either agent alone. Clinical trials with selumetinib, a MEK inhibitor, reported a higher progression-free survival among UM patients (15.9 vs. 7 weeks); however, no clinically meaningful increase in overall survival was observed in comparison to the chemotherapeutic temozolomide in the metastatic setting (10.8 vs. 9.4 months). Additionally, preclinical studies identified that targeting the PI3K/AKT pathway (in GNAQ and GNA11 mutant xenograft models) in combination with a MEK inhibitor may be an effective treatment strategy for patients with GNAQ or GNA11 mutations; however, clinical trials using this combination have stopped due to low response rates and high toxicity. Inhibitors against bromodomain and extraterminal (BET) proteins have had encouraging activity preclinically in UM, which could be further increased by concurrent inhibition of escape mechanisms mediated by fibroblast growth factor receptors. Similarly, targeting microenvironment-derived factors including HGF can also increase MEK inhibitor efficacy against UM cells, preclinically. For UM with BAP1 mutations, it has been shown preclinically that treatment with a histone deacetylase (HDAC) inhibitor could be beneficial. Because BAP1 mutations are associated with loss of melanocytic differentiation, treatment with HDAC inhibitors (valproic acid) are postulated to inhibit the growth of uveal melanoma in vivo by inducing morphological differentiation.

While immune checkpoint inhibitors are the standard of care for cutaneous melanoma, UM has not yet had a phase III clinical trial for immune therapy. Small studies in UM patients (10 patients) treated with pembrolizumab (anti-PD-1) after treatment with ipilimumab reported a median progression-free survival of 18 weeks; ranging from 3.14 to 49.3 weeks. Of the eight evaluable patients, four rapidly progressed, one had stable disease, two had partial responses, and one had a complete response. Although this small study resulted in comparable results seen in patients with non-AL cutaneous melanoma, other studies suggest far lower response rates to single agent anti-PD-1 and combination anti-PD-1 plus anti-CTLA-4 in UM patients. An analysis of Danish UM patients observed partial responses in 7% of patients to anti-PD-1 and 21% to concurrent anti-PD-1 plus anti-CTLA-4. Metastatic UM patients treated with ipilimumab from two additional clinical studies had a median overall survival of 9 months (in contrast to 19.9 months in non-AL cutaneous melanoma). Despite the reduced efficacy of immune checkpoint blockade in UM patients, this option may represent the most effective strategy to date.

Nodular Melanoma -

Nodular melanoma represents the second most common subtype of melanoma, responsible for 10%–15% of total melanomas in Caucasians. NM is the melanoma subtype most associated with increased thickness at clinical presentation, which is attributed to the relatively poorer prognosis of patients with NM. The median age of diagnosis for NM is 53 years, with thicker tumors more common in older patients. NM is more common in women than men for reasons poorly understood and commonly presents de novo on the head, neck, or trunk of patients.

Activating BRAF mutations are detected in patients with NM at a slightly lower frequency relative to SSM, with 43%–47% of patients possessing mutations mostly (88% of cases) in V600E. A recent study identified evidence that BRAFV600E expression may serve as a prognostic marker in primary NM associated with ulceration and reduced survival. Preclinically, it was reported that hyperactivation of the downstream MAPK effector ribosomal protein S6 kinase (RSK1) is detectable in metastatic tumor tissues derived from NM to a higher extent relative to SSM. Activating NRAS mutations are detected at a significantly elevated frequency in NM relative to SSM in 30%–33% vs. 19% of cases, respectively. Interestingly, BRAF and NRAS mutations may not be as mutually exclusive in NM relative to SSM, with the identification of both mutations in the same tumor specimens when assessed by laser capture dissection followed by direct sequencing analysis of exons 11 and 15 of the BRAF gene and exons 1 and 2 of the NRAS gene. Additional high-throughput sequencing of patient-derived samples of single nucleotide variations (SNVs) expected to impact protein coding reveals NOTCH4, RPSKA6, BCL2L12, TERT, ERBB3, ZNF560, SSPO, and SNX31 to be significantly under-mutated in NM relative to SSM.

An analysis of the most recent Surveillance, Epidemiology, and End Results (SEER) cohort and the New York University (NRU) cohort suggests that relative to patients with metastatic SSM treated with BRAF inhibitor (BRAFi) therapy, patients with metastatic NM may respond worse to BRAFi for reasons not completely understood, suggesting the potential existence of distinct clinical and biological properties between NM and SSM. The observation of activated RSK1 via constitutive phosphorylation at the Ser-380 residue may explain the poorer efficacy of BRAFi and/or BRAFi/MEKi in patients with this melanoma subtype. In contrast, no significant difference in response rates and survival was detected in NM versus SSM among a cohort of 154 patients treated with either anti-CTLA-4, anti-PD-1, or the combination of both immune checkpoint inhibitor approaches. Immune checkpoint blockade may serve an ideal first-line therapy for patients with this subtype.

Lentigo Maligna - 

Lentigo maligna (LM) is the third most common subtype of melanoma, comprising roughly 4%–15% of all melanoma cases and its incidence has dramatically increased over the past few decades across the United States, and other regions of the world. LM melanoma typically presents on chronically sun-damaged (CSD) skin of the head and neck, appearing as an irregular brown macule commonly on the head and neck in the elderly. In contrast to the mean age of diagnosis of SSM between 40 and 60 years, the mean age of diagnosis for LM melanoma is 66–72 years. Credit is given to Sir John Hutchinson for the earliest description of LM melanoma in 1890. LM melanoma was initially referred to as “Hutchinson’s melanocytic freckle” due to the prevailing thought that it was benign, non-infectious lesion owing to its slow growing nature. Critical work by Ackerman and Silvers in the late 1970s–1980s finally led to wide acceptance of LM melanoma as a malignant disease worthy of clinical attention and intervention. Chronic ultraviolet radiation is the major risk factor for the development of LM melanoma, which differs from NM and SSM that are associated with intense intermittent ultraviolet radiation exposure. LM melanomas arise most frequently on the face and other sites of chronic sun damage which also differs from NM and SSM that arise most commonly on the trunk in men and legs in women. LM melanoma is thought to occur in older patients due to the increased lifetime sun and ultraviolet radiation exposure.

Lentigo maligna melanomas have a relatively high mutational burden compared to other melanoma subtypes due to chronic ultraviolet exposure. The frequency of activating BRAF mutations in LM is unclear, with reports finding 16.7%–53.4% of LM patients harboring BRAF mutations. The large variation may, in part, be attributed to the regional differences among tested patient tissue cohorts. In a Greek cohort, 16.7% of LM melanoma cases expressed BRAF mutations and 50% of LM cases in a Japanese cohort expressed BRAF mutations. When BRAF mutations are present, the V600K substitution is frequently observed (~77%) relative to the V600E (~23%) as observed in SSM, in this small set of 13 LM patient tumor samples. This finding is consistent with V600K mutations arising on chronically sun-damaged skin. Activating NRAS mutations have been reported to occur in ~8.1%–16% of LM cases .

The treatment of choice for patients with localized LM melanoma consists of surgical excision as first line of therapy, followed by radiation therapy with fractionated superficial radiotherapy, or topical imiquimod cream as an alternative to surgery. Once LM melanoma metastasizes to visceral organs, the five-year survival is similar to SSM. Interestingly, the efficacy of immune checkpoint blockade may be significantly higher in patients with LM melanoma relative to the other subtypes discussed. A study investigating the overall response rate (ORR) of anti-PD-1/PD-L1 in different subtypes of melanoma found patients with melanoma on CSD skin (including LM melanoma, desmoplastic melanoma, and subtype not-specified cases) exhibited an overall response rate of 70%, which fits the theory that cancer cells with high mutational burdens may be more sensitive to immune checkpoint blockade due to the increased presence of immune-stimulatory neoepitopes. Additional investigations on the efficacy of targeted and immune-based therapy are needed specifically for patients with LM melanoma to ensure the optimal treatment(s) is identified for this cohort and further improved through preclinical experimentation and clinical trials.

To date, this is the most comprehensive review of the data and treatments best suited for these melanoma subtypes that I have found.  So hoping that understanding and effective treatment options increase for these patients very soon.  -  c

For Mat: CDK4/6 inhibitors, PLX8394, or copper chelation?????

Thought about you all day my friend.  Between planting 9 million iris bulbs and repairing a brick wall (mortar mix is an amazing desiccant from which my hands may never recover) at my daughter's "new" house, while shouting curse words (in my head) on your behalf, that even my most tolerant blog audience may find cringe worthy...this is what I (and a brain far better than mine) came up with:

For those unaware of Amazing Mat...I am thinking of a CURE for someone already experienced in BRAF/MEK, ipi, and Keytruda with a brain met near the optic nerve.

Here goes: 

CDK4/6 inhibitors:  
90% of melanoma patients are positive for CDK4/6.
The inhibitor has been proven to cross the blood brain barrier.
Sosman at Vanderbilt has been working with this under the name of LEE011 for some time.
Clinical Trial - NCT01777776: LEE011 and LGX818  is noted to be "active, but not recruiting".
Check out this post from ASCO 2015 (second abstract) where one version (P1446A-05 [voruciclib]) is combined with vermurafenib:  ASCO 2015 new BRAF inhibitor combos
Several other trials with the drug are also noted to be "suspended".  On researching them, the suspension does not appear to be due to patient problems, rather they are due to decisions made by BIG Pharma.
Another CDK4/6 inhibitor:  Palbociclib (PD-0332991) demonstrated "stability" in 27% of patients with melanoma and other cancers.  In another study, a partial response was found in 1 of 31 patients and stability in 29%.
When LEE011 and Binimetinib were combined:  Folks with NRAS mutant melanoma (which may be precluded by your BRAF + status, Mat....but you never know) demonstrated a partial response of 43% as well as stable disease in 43%....per report in Jan 2015.
It's a long shot....but I would call Sosman.  What the heck?  All he can say is no.

A more effective, new generation, BRAF inhibitor - PLX8394?!!!
PLX8394  treats wild and mutated BRAF status melanoma.
May be more effective in BRAF mutated tumors not responsive to other BRAF inhibitors.
Clinical trial #:  NCT02428712 - A study of PLX8394
You have to be refractory to BRAF/MEK, ipi and/or pembro (CHECK!!!).
Do have to have stable brain mets for one month, but sounds pretty flexible and can even be stable on prednisone.
Currently recruiting in Texas, Michigan, Arizona and Utah.

Copper chelation:
Apparently copper is an important co-factor for BRAF mutant melanoma and there is some animal evidence that reducing body levels of copper may inhibit melanoma cells.  Copper chelation for BRAF mutated disease
What's the easiest way to do this?  Duke has been looking at this with an already available drug used to treat copper overload:  Trietine combined with vemurafenib.   Copper starvation could be a promising treatment for some cancers
Clinical trial #:  NCT02068079  Copper chelation and Duke Study
Unfortunately, this study is also "active, but not recruiting".
I would still call.   But, I'm like that.

Much love and warm wishes.  Still thinking. - c

ASCO 2017: Hope for NRAS melanoma

Melanoma is a complicated disease entity to say the least.  Tumors, that are now all lumped together as 'melanoma' demonstrate many different mutations and develop via a variety of pathways.  About half of us are BRAF positive.  Aboust 20% of us have the NRAS mutation.  Then there's all sorts of other delineations!  This post:  What tangled paths we weave...
Which contains this diagram:

Probably makes the pathway as clear as anything else!!

Thus far, targeted therapy (using a combination of a BRAF inhibitor with a MEK inhibitor) has been found to be most effective for only those with a V600 BRAF mutated melanoma.  However, this post in 2016 addresses how nelfinavir (also called Viracept, an HIV protease ihibitor) can be used to decrease resistance to those meds in both BRAF and NRAS mutant melaonma:  Stopping resistance to targeted therapy- nelfinavir- for BRAF and NRAS mutant melanoma

Here an older cardiac drug was paired with a MEK inhibitor: Digoxin and trametinib for BRAF wild type melanoma

Recently I posted this study in which binimetinib (a MEK inhibitor) was paired with encorafenib (a BRAF inhibitor):   Encorafenib/binimetinib, a BRAF/MEK combo = 14.9 month PFS
Within it was noted that, "In March, Array withdrew its FDA new drug application for single-agent binimetinib as a treatment for patients with NRAS-mutant advanced melanoma, based on feedback from the FDA during a preplanned review meeting."

However, from ASCO  2017...this study pairs binimetinib with ribociclib (also named Kisquali [What the f@%K?????] a  CDK 4/6 inhibitor, approved this year for use in HR+/HER 2 breast cancer):  

Phase 1b/2 trial of ribociclib+binimetinib in metastatic NRAS-mutant melanoma: Safety, efficacy, and recommended phase 2 dose (RP2D).

2017 ASCO. J Clin Oncol 35, 2017. Schuler, Ascierto....Postow....Sosman....Daud...et al.

Background: Simultaneous inhibition of MEK and CDK4/6 may suppress MAPK pathway activation and cell-cycle checkpoint dysregulation in NRAS-mutant melanoma, resulting in enhanced antitumor activity. Phase 1b data are reported. Methods: The phase 1b primary objective was to determine maximum tolerated dose (MTD)/RP2D. A 28-d cycle of oral ribociclib (RIBO) once daily (QD) for 21 d + oral binimetinib (BINI) twice daily (BID) for 28 d, and a 21-d cycle of RIBO QD + BINI BID, both for 14 d per cycle, were evaluated. Secondary objectives were to evaluate efficacy, safety and pharmacodynamics. Results: Based on dose escalation, MTD was 600mg RIBO/45mg BINI for the 21-d and 200/45 for the 28-d regimens. Due to promising activity, the 28-d cycle was selected as RP2D (unconfirmed partial response [PR] with limited follow-up occurred in 35% of pts).  As of Jan 2017, the RP2D was received by 16 pts in phase 1b (ECOG PS 0/1/2, 63%/31%/6%; elevated lactate dehydrogenase, 44%; stage IVM1c disease, 50%; prior ipilimumab [ipi], 44%; prior anti–programmed death [PD]-1/PD-L1, 31%). Median (range) exposure was 4 (0–13) mo. Common adverse events (AEs) were increased blood creatine phosphokinase, elevated AST, peripheral edema, acneiform dermatitis, diarrhea and fatigue. Common grade 3/4 AEs were elevated AST and ALT (19%/6%), nausea (19%/0%), rash (19%/0%), vomiting (6%/6%) and neutropenia (12%/0%). Confirmed PR (cPR) occurred in 4 pts (25%; time to response, 48–168 d), stable disease in 7 pts (44%), disease progression in 3 pts (19%); 2 pts (12%) were not evaluable. Among cPR pts, 3 had prior ipi and/or anti–PD-1/PD-L1. Median progression-free survival (mPFS) was 6.7 mo. Sequence analysis of synchronous non-RAS genetic alterations will be presented. Conclusions: Combined RIBO/BINI at the selected RP2D had a manageable safety profile and favorable efficacy (based on mPFS) for NRAS-mutant melanoma in phase 1b. Based on these promising data, the phase 2 expansion is underway to assess antitumor activity at the RP2D. Clinical trial information: NCT01781572

So both are oral meds...given in a 28-day cycle as noted above, to 16 patients - 44% of whom had increased LDH, 44% had been previously given ipi, 31% had been previously treated with anti-PD-1 or anti-PD-L1.  Meds were given for an average of 4 months.  There was a confirmed partial response in 4 patients, stable disease in 7, disease progression in 3 and 2 were not evaluated.  For what it's worth...

When looking at immunotherapy in NRAS patients, I posted this in 2015:  Good news for NRAS positive folks, especially in regard to anti-PD1!!!! Now there is this:

NRAS-mutated melanoma patients have similar response rates to therapy with checkpoint inhibitors as other cohorts.

2017 ASCO. J Clin Oncol 35, 2017. Kirchberger, Ugurel, Mangana, et al.

Background: About 20% of metastatic melanomas harbor NRAS mutations which constitutively activate the MAPK pathway, driving cell proliferation and inhibiting apoptosis. The response of patients with NRAS-mutated melanoma to checkpoint inhibitor therapy is so far unknown. A previous study suggested a higher response rate of NRAS-mutated melanoma to anti-PD-1/anti-PD-L1 with an objective response in 7 out of 11 (64%) patients compared to 35% and 21% in BRAF wildtype or BRAF V600-mutated melanoma, respectively. Methods: In total, 224 patients with NRAS-mutated melanoma were analyzed. Of these, 180 patients received ipilimumab, 98 anti-PD1 monotherapy, and one patient combined ipilimumab and anti-PD1 therapy. We evaluated overall response rate (ORR), disease control rate, progression-free survival (PFS) and overall survival to checkpoint inhibitor therapy in these patients. Results: In this patient cohort with NRAS-mutated melanoma, 27% had brain metastases, 62% an elevated LDH and 22% an ECOG greater than/ = to 1. ORR was 15% for treatment with ipilimumab and 34% for anti-PD1 therapy. Disease control rates were 27% for ipilimumab and 52% for anti-PD1 therapy. PFS was 4.5 months for ipilimumab and 11.4 months for anti-PD1 therapy. Overall survival of all patients was 29 months. Conclusions: The efficacy data of ipilimumab or anti-PD1 therapy in NRAS-mutated melanoma patients were similar to the known response rates of NRAS wildtype melanoma patients.

In this study, 224 NRAS mutated melanoma patients were studied. 180 were treated with ipi, 98 with anti-PD-1 and 1 was given the ipi/nivo combo.  The overall response rate was 15% for those treated with ipi and 34% for those treated with anti-Pd-1....which is in keeping with response rates for those drugs generally.

Good to know. - c

Everything cures melanoma, installment #11!!!!

It's been a while since my last update on these "crazy" items, extracts, etc. that can kill/cure melanoma!!!  Yep, I've been cataloging all these CURES for years:  Everything Cures Melanoma - Installment #10  I see all sorts of strange reports like these all the time, but the last two additions pushed me over the edge. So, here's my latest collection:

Anti-tumor and anti-metastasis activities of honey bee larvae powder by suppressing the expression of EZH2. Kageyama, Li, Sun, et al.  Biomed Pharmacother. 2018 Jun 12.

Honey bee larvae products have been widely used as traditional daily supplements and complementary medicine for health promotion. However, there is little scientific evidence about their bioactivities. This study was designed to examine the anti-tumor and anti-metastasis effects of honey bee larvae powder (HLP) and explore the underlying mechanism. A subcutaneous transplantation model (murine breast cancer cell 4T1-LUC) and lung metastasis model (murine melanoma cell B16-F10) were established to evaluate the anti-tumor and anti-metastasis effects of HLP. Honey bee larvae powder extract (HLE) was obtained by 70% ethanol extraction, and its chemical composition was determined according to physiochemical methods. Cell Counting Kit-8 assay was performed to test the cytotoxicity of HLE, and qRT-PCR assays were conducted to examine the mRNA levels of tumor marker EZH2 in HLE-treated tumor cells. In vivo xenograft tumor assays in BALB/c mice revealed dose-dependent suppression of tumor growth and lung metastasis showing an inhibition rate of 37.5% and 70.4% at 6 g/kg HLP-administered group with no toxicity to the animals. In vitro studies indicated that HLE showed no cytotoxicity to cancer cells at doses up to 1000 μg/mL, however, it significantly decreased EZH2 mRNA levels in HLE (1000 μg/mL)-treated B10-F10 cells (28.49%) and 4T1-LUC cells (26.75%). Further studies to elucidate the mechanisms involved and to isolate the active components of honey bee larva may provide more valuable information for its development and application in cancer treatment.

6- and 8-Prenylnaringenin, Novel Natural Histone Deacetylase Inhibitors Found in Hops, Exert Antitumor Activity on Melanoma Cells. Venturelli, Niessner, Sinnberg, et al.Cell Physiol Biochem. 2018 Nov 20.

Prenylnaringenins are natural prenylflavonoids with anticancer properties. However, the underlying mechanisms have not been elucidated yet. Here we report a novel mode of action of 6- and 8-prenylnaringenin (PN) on human melanoma cells: Inhibition of cellular histone deacetylases (HDACs).  We performed in silico and in vitro analyses using 6-PN or 8-PN to study a possible interaction of 6-PN or 8-PN with HDAC as well as Western blot and FACS analyses, real-time cell proliferation and cell viability assays to assess the impact of 6-PN and 8-PN on human metastatic melanoma cells.
In silico, 6-PN and 8-PN fit into the binding pocket of HDAC2, 4, 7 and 8, binding to the zinc ion of their catalytic center that is essential for enzymatic activity. In vitro, 100 µmol/L of 6-PN or 8-PN inhibited all 11 conserved human HDAC of class I, II and IV. In clinical oncology HDAC inhibitors are currently investigated as new anticancer compounds. In line, treatment of SK-MEL-28 cells with 6-PN or 8-PN induced a hyperacetylation of histone complex H3 within 2 h. Further, 6-PN or 8-PN mediated a prominent, dose-dependent reduction of cellular proliferation and viability of SK-MEL-28 and BLM melanoma cells. This effect was apoptosis-independent and accompanied by down-regulation of mTOR-specific pS6 protein via pERK/pP90 in SK-MEL-28 cells.  The identification of a broad inhibitory capacity of 6-PN and 8-PN for HDAC enzymes with antiproliferative effects on melanoma cells opens the perspective for clinical application as novel anti-melanoma drugs and the usage as innovative lead structures for chemical modification to enhance pharmacology or inhibitory activities.


Botanical Therapeutics: Phytochemical Screening and Biological Assessment of Chamomile, Parsley and Celery Extracts against A375 Human Melanoma and Dendritic Cells. Danciu, Zupko, Bor, et al. Int J Mol Sci. 2018 Nov 16.

Chamomile, parsley, and celery represent major botanical sources of apigenin, a well-known flavone with chemopreventive properties. The aim of this study was to assess the phytochemical composition, antioxidant, and anti-inflammatory potential of methanol extracts obtained from chamomile, parsley, and celery collected from Romania, as well as the biological activity against A375 human melanoma and human dendritic cells. Results have shown that all three extracts are rich in polyphenolic compounds and flavonoids, and they generate a radical scavenger capacity, iron chelation potential, as well as lipoxygenase inhibition capacity. Chamomile and celery extracts present weak antiproliferative and pro-apoptotic properties in the set experimental conditions, while parsley extract draws out significant pro-apoptotic potential against A375 human melanoma cells. Parsley and chamomile extracts affected the fibroblast-like morphology of the screened tumor cell line. On the other hand, chamomile and celery extracts abrogated the expansion of LPS-activated dendritic cells, while the metabolic activity was attenuated by stimulation with celery extract; chamomile and parsley extracts had no effect upon this parameter. Chamomile and parsley extracts incubation with naive dendritic cells did not trigger cytokine secretion (TNF-alpha, IL-6, IL-10), but celery extract stimulation significantly reduced the anti-inflammatory, cytokine IL-10.

Anti-cancer effect of dung beetle gludosaminoglucans on melanoma.  Ahn, Kim, Kim, et al. BMC Cancer. 2019 Jan 5.

Dung beetle glycosaminoglycan is known to possess anti-aging activities. However, its anti-cancer mechanisms are not fully elucidated yet. The objective of this study was to evaluate the anti-cancer effect of insect-derived polymer dung beetle glycosaminoglycan (GAG) after intraperitoneally injecting it to melanoma mice induced by B16F10 cells.  To determine molecular mechanism involved in the anti-cancer effect of dung beetle GAG, its origin N-glycan under 3KD Dalton was assayed for melanoma cell cytotoxicity. Quantitative comparisons of adhesive molecule on extracellular matrix and activities of tissue inhibitor of metalloprotease 2 (TIMP-2) were also investigated. In vivo anti-cancer effect of dung beetle GAG on solid tumor size, survival time and gene-expression profiles was also assayed using B10F10 melanoma mice model. Mice with induced melanoma were then treated with Catharsius molossus (dung beetle) GAG (CaG) at 5 mg/kg for 8 weeks to investigate its anti-cancer effects compared to bumblebee (Bombus ignitus) queen glycosaminoglycan (IQG) and Huechys sanguinea glycosaminoglycan (HEG).  These N-glycans derived from these GAG were composed of many linear heparinoid polysaccharides, polymers with hexose and N-acetylhexose. Adminstration with these GAGs increased survival time and decreased melanoma sizes in mice, in accordance with their inhibitory effects on cell growth ratio of melanoma B16F10. In addition, treatment with N-glycans derived from theses glycosaminoglycan increased activities of TIMP-2 in HMVEC cells pretreated with TNF-alpha and in melanoma cells, suggesting that they had anti-inflammatory and anticancer activities. In DNA microarray results, compared to control, CaG treated mouse group showed upregulation of 192 genes including collagen,typeI,alpha1 (Col1a1), consistent with the highly increased in vitro extracellular matrix (ECM) adhesion on collagen 1 and up-regulation of heparanase (Hpse). After treatment with CaG, a total of 152 genes were down-regulated, including nuclear RNA export factor (Nxf3) and hyaluronan proteoglycan link protein1.  Glycosaminoglycan, CaG can strengthen ECM by increasing activity of TIMP-2 and adhesion activity on collagen known to inhibit changes of ECM, leading to tumor cell invasion and progression.

Inositol hexaphosphate plus inositol induced complete remission in stage IV melanoma: a case report. Khurana, Baldeo, Joseph. Melanoma Res. 2019 Jan 5.

Inositol hexaphosphate (IP6) also called phytic acid is a polyphosphorylated carbohydrate naturally found in cereals, nuts, grains, and high-fiber-containing foods. It has been shown to inhibit the growth of many different tumor cell lines both in vitro and in vivo like colon, pancreas, liver, prostate, and even melanoma. Vitamin B inositol is a precursor of IP6 and another naturally occurring compound with anticancer properties. We present a case report of a patient with metastatic melanoma who declined traditional therapy and opted to try over the counter supplement IP6+inositol instead. To our surprise, the patient achieved a complete remission and remains in remission 3 years later. On the basis of this case and previous preclinical studies, we believe further research is indicated in exploring antiproliferative and potential immune stimulating effects of IP6+inositol in patients with metastatic melanoma.

Anti-melanization effects and inhibitory kinetics of tyrosinase of bird's nest fern (Asplenium australasicum) frond extracts on melanoma and human skin. Zend and Lai. J Biosci Bioeng. 2019 Jan 10.

Some bioactive properties of p-coumaric acid and fucose-rich polysaccharide in skin health have been studied, including melanogenesis inhibition of the phenolic acid and growth inhibitory effects of the polysaccharide on melanoma. The dermatological benefits of bird's nest fern extracts (BNFE), containing both substantial fucose-rich polysaccharide and p-coumaric acid, like promoting collagen production and growth of fibroblast cell and further improving the elasticity and dryness of human skins have been demonstrated in our previous study. Besides, the anti-melanization effects of various BNFE on B16-F10 melanoma and human skin were first studied here. The promising extracts revealed that the main phenolic acid, p-coumaric acid, in BNFE resulted in suppression against tyrosinase activity from melanogenesis. The inhibitory kinetics on the diphenolase activity indicated that AE40 was a noncompetitive inhibitor of mushroom tyrosinase. On the other hand, the fucose-rich mucilage of BNFE showed pronouncedly suppressing effect on B16-F10 melanoma viability. Clinical trial was performed by recruiting 46 female volunteers and the results indicated that the lotions with 1% of BNFE was non-irritant and reduced effectively the pigmentation on human skin after 7-14 days of continuous application. It was suggested that the fucose-rich mucilage and p-coumaric acid in BNFE may have potential for nutricosmetics and phytotherapy applications as a natural hypopigmenting agent.

Uncovering the anti-proliferation mechanism and bioactive compounds in red kidney bean coat against B16-F10 melanoma cells by metabolomics and network pharmacology analysis.  Nie, Huang, Wu, et al. Food Funct. 2019 Jan 30.

In this study, coat (RKBC) and kernel (RKBK) extracts of red kidney bean were prepared, and their chemical compositions and potential anti-cancer activity against B16-F10 cells were evaluated. Then the anti-proliferation mechanisms of the active RKBC extract were investigated by flow cytometry analysis, cellular metabolomics, network pharmacology and western blotting. The RKBC extract inhibited B16-F10 cell proliferation and migration in a dose-dependent manner. Further analysis showed that RKBC induced G1 and G2/M phase arrest, and triggered apoptosis and vacuolization. Mechanistically, RKBC significantly increased the cellular content of cGMP, decreased the levels of AKT1/2/3 and cleaved-MMP2, and up-regulated the expression of Bcl-xl. Besides, network pharmacology revealed that RKBC potentially influenced the cell cycle via the regulation of CDK2 and CDK4. Finally, quercetin might serve as the major active component in the RKBC extract. In conclusion, our study showed the potential of the RKBC extract for the prevention or treatment of melanoma.

Effect of Sucrier Banana Peel Extracts on Inhibition of Melanogenesis through the ERK Signaling Pathway.  Phacharapiyangkul, Thirapanmethee, Sa-Ngiamsuntorn, et al.  Int J Med Sci. 2019 Apr 25.

Hyperpigmentation is a type of pigmentary disorder induced by overexpression of melanin content activated severe esthetic problems as melasma, freckle, ephelides, lentigo and other forms on human skin. Several whitening agents have restricted use because of their side effects or stability such as kojic acid, ascorbic acid and hydroquinone can act as cytotoxic substance which associated to dermatitis and skin cancer. To find for the safe substance, this study aimed to find for the ability of several components in Sucrier banana peel (SBP) extracts to inhibit melanogenesis process through p38 signaling pathway in B16F10 mouse melanoma cells. Tyrosinase activity and the cellular melanin content were dose dependent manner decreasing after SBP treatment. Furthermore, SBP decreased the expression of melanogenesis relate protein as microphthalmia-associated transcription factor (MITF) and tyrosinase protein after 24 hours incubation with α-melanocyte stimulating hormones (MSH) stimulating. The findings demonstrated that SBP contained an effective agent for hyperpigmentation inhibitor through p38 signaling pathways without any effect to ERK pathway, and subsequent down-regulate MITF expression and tyrosinase enzyme family production.

Bullfrog oil (Rana catesbeiana Shaw) induces apoptosis, in A2058 human melanoma cells by mitochondrial dysfunction triggered by oxidative stress.  Amaral-Machado, Oliveira, Alencar, et al. Biomed Pharmacother. 2019 Jun 13 

Bullfrog oil, an animal oil extracted from the adipose tissue of Rana catesbeiana Shaw, showed promising cytotoxic activity against melanoma cells and, therefore, has the potential to become a pharmaceutical active compound. However, there is a lack of information regarding the pathways involved in its pharmacological activity. Thus, the aim of this study was to investigate and elucidate the cytotoxic effect of this oil against A2058 human melanoma cells. The cytotoxic potential was evaluated by the MTT assay, the cell cycle analysis and the cell death assay. In addition, the apoptotic potential was investigated by (i) the DNA fragmentation using propidium iodide staining analysis, (ii) the evaluation of mitochondrial membrane potential and (iii) the determination of intracellular Reactive Oxygen Species (ROS) level. The results showed that the bullfrog oil was able to promote a time-dependent cytotoxic effect, decreasing cell viability to 38% after 72 h of treatment without affecting the cell cycle. Additionally, the bullfrog oil induced the apoptosis in A2058 cells, increasing up to 50 ± 13% of the intracellular ROS level, maintaining the DNA integrity and promoting an approximate decrease of 35 ± 5% in the mitochondrial membrane potential. It can be concluded that the in vitro cytotoxic effect of the bullfrog oil in A2058 human melanoma cells is mediated by oxidative stress that induces mitochondrial dysfunction, triggering the apoptosis. These unprecedented results highlight the pharmacological potential of bullfrog oil and provide important information to support studies on the development of new pharmaceutical products for complementary and alternative treatments for melanoma.

Citrus unshiu peel suppress the metastatic potential of murine melanoma B16F10 cells in vitro and in vivo.  Choi, Lee, Hwang, et al.  Phytother Res. 2019 Sep 4. 

The peel of Citrus unshiu Marcow. fruits (CU) has long been used as a traditional medicine that has therapeutic effects against pathogenic diseases, including asthma, vomiting, dyspepsia, blood circulation disorders, and various types of cancer. In this study, we investigated the effect of CU peel on metastatic melanoma, a highly aggressive skin cancer, in B16F10 melanoma cells, and in B16F10 cells inoculated-C57BL/6 mice. Our results show that ethanol extracts of CU (EECU) inhibited cell growth and increased the apoptotic cells in B16F10 cells. EECU also stimulated the induction of mitochondria-mediated intrinsic pathway, with reduced mitochondrial membrane potential and increased generation of intracellular reactive oxygen species. Furthermore, EECU suppressed the migration, invasion, and colony formation of B16F10 cells. In addition, the oral administration of EECU reduced serum lactate dehydrogenase activity without weight loss, hepatotoxicity, nor nephrotoxicity in B16F10 cell-inoculated mice. Moreover, EECU markedly suppressed lung hypertrophy, the number and expression of metastatic tumor nodules, and the expression of inflammatory tumor necrosis factor-alpha in lung tissue. In conclusion, our findings suggest that the inhibitory effect of EECU on the metastasis of melanoma indicates that it may be regarded as a potential therapeutic herbal drug for melanoma.

Kunitz type protease inhibitor from the canine tapeworm as a potential therapeutic for melanoma.  Ranasinghe, Rivera, Boyle, et al. Sci Rep. 2019 Nov 7. 

Modulating the tumor microenvironment to promote an effective immune response is critical in managing any type of tumor. Melanoma is an aggressive skin cancer and the incidence rate is increasing worldwide. Potent protease inhibitors have recently been extensively researched as potential therapeutic agents against various cancers. EgKI-1 is a potent Kunitz type protease inhibitor identified from the canine tapeworm Echinococcus granulosus that has shown anti-cancer activities in vivo. In this study we show that EgKI-1 significantly reduced the growth of melanoma in the B16-F0 mouse model and was not toxic to normal surrounding tissue. Moreover, EgKI-1 treatment significantly reduced survivin expression levels and increased the CD8+ T cell population in draining axillary lymph nodes. Therefore, EgKI-1 potentially reduces tumor growth by inducing apoptosis and modulating the tumor microenvironment, and has potential for development as an intra-lesional treatment for melanoma.

Cyclic analogues of horseshoe crab peptide tachyplesin I with anticancer and cell penetrating properties.  Vernen, Craik, Lawrence, et al.  ACS Chem Biol.  2019 Nov 12.

Tachyplesin-I (TI) is a host defense peptide from the horseshoe crab Tachypleus tridentatus that has outstanding potential as an anticancer therapeutic lead. Backbone cyclized TI (cTI) has similar anticancer properties to TI, but has higher stability and lower hemolytic activity. We designed and synthesized cTI analogues to further improve anticancer potential and investigated structure-activity relationships based on peptide-membrane interactions, cellular uptake and anticancer activity. The membrane-binding affinity and cytotoxic activity of cTI were found to be highly dependent on peptide hydrophobicity and charge. We describe two analogues with increased selectivity toward melanoma cells and one analogue with ability to enter cells with high efficacy and low toxicity. Overall, the structure-activity relationship study shows that cTI can be developed as a membrane-active antimelanoma lead, or be employed as a cell penetrating peptide scaffold that can target and enter cells without damaging their integrity.

Honey bee babies, celery, parsley, fern, bull frog oil, banana peel, bean skin, dog worm, horseshoe crab goo cocktail with a twist of unshiu along with a beer chaser and dung beetle poo poo platter, anyone?  Hey, if they can make it work in real live ratties, I'll sign up!!!

Have a great weekend guys!   - c

Copper Chelation to inhibit BRAF V600E melanoma growth and decrease resistance to BRAF/MEK inhibitors???

I've actually reported on Copper Chelation and melanoma before.  Here is this from 2015:  CDK4/6 inhibitors, PLX8394, or copper chelation?????

Now there's this:

Copper Chelation Inhibits BRAFV600E-driven Melanomagenesis and Counters Resistance to BRAFV600E and MEK1/2 Inhibitors. Counter, Crowe, Greenberg and Brady.  Cancer Res. 2017 Oct 6.

MEK1/2 and BRAFV600E inhibitors are used to treat BRAFV600E-positive melanoma, with other cancers under evaluation. Genetic perturbation of copper import or pharmacological reduction of copper with the clinical copper chelator TTM inhibits MEK1/2 kinase activity and reduces BRAFV600E-driven tumorigenesis. In this study, we report that TTM inhibited transformed growth of melanoma cell lines resistant to BRAF or MEK1/2 inhibitors and enhanced the antineoplastic activity of these inhibitors. TTM also provided a survival advantage in a genetically engineered mouse model of melanoma, and when accounting for putative overdosing, trended towards an increase in the survival benefit afforded by BRAF inhibition. This effect was phenocopied by genetically inhibiting copper import in tumors, which was linked to a reduction in MAPK signaling. Thus, TTM reduces copper levels and MAPK signaling, thereby inhibiting BRAFV600E-driven melanoma tumor growth. These observations inform and support clinical evaluation of TTM in melanoma.

Sounds good to me!  Hang in there ratties!  -  c

In melanoma care....we've come a long way baby!!!

Real-world treatment practice in patients with advanced melanoma in the era before ipilimuab:  results from the IMAGE study.  Middleton, Dalle, Claveau, et al.  Cancer Med 2016 4/26. 

The therapeutic landscape for advanced melanoma has recently been transformed by several novel agents (immune checkpoint inhibitors and molecular-targeted agents). The prospective, multi-site, observational study IMAGE (ipilimumab: management of advanced melanoma in real practice) included a retrospective cohort to describe real-world treatment prior to approval of the immune checkpoint inhibitor ipilimumab. This retrospective cohort of patients, who started second-line/subsequent treatment for advanced melanoma within 3 years before ipilimumab approval, was selected randomly by chart review. Collected data included treatment history, patient outcomes, and healthcare resource utilization. All patients had ≥1 year of follow-up data. This analysis included 177 patients from Europe (69%) and North America (31%). The most common index therapies (used alone or in combination) were fotemustine (23%), d
acarbazine (21%), temozolomide (14%), and platinum-based chemotherapy (14%). Most patients (89%) discontinued treatment during the study period; the most common reason was disease progression (59%). Among patients with tumor assessment (153/177; 86%), 2% had complete response, 5% had partial response, and 12% had stable disease on last tumor assessment. At 1-year study follow-up, median progression-free survival was 2.6 months and median overall survival was 8.8 months. During follow-up, 95% of the patients had healthcare visits for advanced melanoma, 74% of whom were hospitalized or admitted to a hospice facility. These results provide insights into patient care with advanced melanoma in the era before ipilimumab and may serve as a benchmark for new agents in future real-world studies.

So this was 177 folks being treated from 2008 - 2010....not that long ago.....before ipi, BRAFi and anti-PD1 were FDA approved.  And "at 1-year study follow-up, median progression-free survival was 2.6 months and median overall survival was 8.8 months."   While in this study:  Pembro/keytruda's overall response  Pembro provided a "12-month progression-free survival rate of 35%, and median overall survival of 23 months."  And here:  Nivolumab/Opdivo shows impressive OS  "the median OS was 20.3 months, the 5-year OS rate was 35.3% and the 30-month PFS rate was 25.7%."  We know the benefits BRAFi can provide...if only short term....but with some adjustments others are reaping their benefits and managing side effects for years.  Additionally, work continues to be done by researchers and ratties in the area of immunotherapy combo's, IDO inhibitors, LAG3, CDK4/6 inhibitors, various meds/treatments that prevent tumor resistance to BRAFi, DNA pcr and tumor testing that may help determine who will respond to what treatment....

But...it is not enough....not nearly enough.  Holding many of my amazing peeps in my heart today....Dfeng, Charlie S, Josh, John and so many others....hang in there guys....hang in there. love, c

What the Melanoma Big Dogs are working on in 2017!!!

Immunotherapy!  Targeted therapy!  TIL!  CARs!  Intratumoral therapies!  Here we go!!!!

Novel Checkpoints and Cosignaling Molecules in Cancer Immunotherapy.  Giuroiu, Weber. Cancer J. 2017 Jan/Feb.

The recent demonstration of the antitumor efficacy of checkpoint protein inhibition has resulted in the approval of blocking antibodies against the programmed cell death 1 (PD-1)/programmed cell death ligand 1 (PD-L1) pathway in multiple different histologic findings. Therapeutic successes with PD-1/PD-L1 antibodies in melanoma and lung cancer have been followed by approvals in bladder, renal, and head and neck cancers and Hodgkin lymphoma, with others undoubtedly to come. However, PD-1 is only one of many checkpoints and agonistic regulatory molecules expressed on T cells by which maintenance of the balance between costimulatory and coinhibitory signaling pathways is perturbed in cancer. The manipulation of many of these molecules in cancer patients might be associated with clinical benefit. The majority of the T-cell cosignaling receptors belong to either the immunoglobulin superfamily or the tumor necrosis factor receptor superfamily. A total of 29 immunoglobulin superfamily and 26 tumor necrosis factor receptor superfamily cosignaling receptors have been identified that are expressed on T cells, providing fertile ground for development of inhibitory or agonistic antibodies and small molecules as cancer therapeutics. In the current work, we focus on some of the most promising new checkpoints and agonistic or cosignaling molecules that are in early clinical development as single agents or in combinations with PD-1/PD-L1, cytotoxic T-lymphocyte-associated protein 4 blockade, or chemotherapy with an emphasis on those that have reached the clinic and on important targets that are in late preclinical development.

Novel Targeted Therapies for Metastatic Melanoma.  Iams, Sosman, Chandra.  Cancer J.  2017 Jan/Feb.

Oncogene-targeted therapy is a major component of precision oncology, and although patients with metastatic melanoma have experienced improved outcomes with this strategy, there are a number of potential therapeutic targets currently under study that may further increase the drug armamentarium for this patient population. In this review, we discuss the landscape of targeted therapies for patients with advanced melanoma, focusing on oncogene mutation-specific targets. In patients with typical BRAF V600-mutant melanoma, combination BRAF and MEK inhibition has surpassed outcomes compared with monotherapy with BRAF or MEK inhibition alone, and current strategies seek to address inevitable resistance mechanisms. For patients with NRAS-mutant melanoma, MEK inhibitor monotherapy and combined MEK and CDK4/6 inhibition are burgeoning strategies; for patients with KIT-mutant melanoma, tyrosine kinase inhibition is being leveraged, and for NF-1-mutant melanoma, mTOR and MEK inhibition is being actively evaluated. In patients with atypical, non-V600 BRAF-mutant melanoma, MEK inhibitor monotherapy is the potential novel targeted approach on the horizon. For advanced uveal melanoma, novel targets such as IMCgp100 and glembatumumab have shown activity in early studies. We review additional strategies that remain in the preclinical and early clinical pipeline, so there is much hope for the future of targeted agents for distinct molecular cohorts of patients with advanced melanoma.

Adoptive Cell Therapy for Metastatic Melanoma.  Merhavi-Shoham, Itzhaki, Markel, et al. Cancer J. 2017 Jan/Feb.  

Adoptive cell therapy (ACT) of tumor-infiltrating lymphocytes (TILs) is a powerful form of immunotherapy by inducing durable complete responses that significantly extend the survival of melanoma patients. Mutation-derived neoantigens were recently identified as key factors for tumor recognition and rejection by TILs. The isolation of T-cell receptor (TCR) genes directed against neoantigens and their retransduction into peripheral T cells may provide a new form of ACT.  Genetic modifications of T cells with chimeric antigen receptors (CARs) have demonstrated remarkable clinical results in hematologic malignancies, but are so far less effective in solid tumors. Only very limited reports exist in melanoma. Progress in CAR T-cell engineering, including neutralization of inhibitory signals or additional safety switches, may open opportunities also in melanoma.We review clinical results and latest developments of adoptive therapies with TILs, T-cell receptor, and CAR-modified T cells and discuss future directions for the treatment of melanoma.

Intratumoral Approaches for the Treatment of Melanoma.  Bommareddy, Silk, Kaufman.  Cancer J. 2017 Jan/Feb.

There have been significant advances in the immunotherapy of melanoma over the last decade. The tumor microenvironment is now known to promote an immune-suppressive milieu that can block effective immune-mediated tumor rejection. Several novel strategies designed to overcome local immunosuppression hold promise for treatment of melanoma and other cancers. These approaches include oncolytic viruses, plasmid DNA delivery, Toll-like receptor agonists, inflammatory dyes, cytokines, checkpoint inhibitors, immunomodulatory agents, and host and pathogenic cell-based vectors. In addition, there are several novel methods for local drug delivery, including direct injection, image-guided, electroporation, and nanodelivery techniques under study. The approval of talimogene laherparepvec (Imlygic), an attenuated, recombinant oncolytic herpesvirus, for melanoma treatment is the first intratumoral agent to receive regulatory approval for the treatment of patients with melanoma. This review will focus on the rationale for intratumoral treatment in melanoma, describe the clinical and safety data for some of the agents in clinical development, and provide a perspective for future clinical investigation with intratumoral approaches. Melanoma has been a paradigm tumor for progress in targeted therapy and immunotherapy and will likely also be the tumor to establish the therapeutic role of intratumoral treatment for cancer.

Sounds good!  I like a multi-faceted approach.  Now!  Let's make it so!  Double time!!!! - c