Medical management of melanoma

PAK1 and Therapy Resistance in Melanoma

Malignant melanoma claims more lives than any other skin malignancy. While primary melanomas are usually cured via surgical excision, the metastatic form of the disease portents a poor prognosis. Decades of intense research has yielded an extensive armamentarium of anti-melanoma therapies, ranging from genotoxic chemo- and radiotherapies to targeted interventions in specific signaling pathways and immune functions. Unfortunately, even the most up-to-date embodiments of these therapies are not curative for the majority of metastatic melanoma patients, and the need to improve their efficacy is widely recognized. Here, we review the reports that implicate p21-regulated kinase 1 (PAK1) and PAK1-related pathways in the response of melanoma to various therapeutic modalities. Ample data suggest that PAK1 may decrease cell sensitivity to programmed cell death, provide additional stimulation to growth-promoting molecular pathways, and contribute to the creation of an immunosuppressive tumor microenvironment. Accordingly, there is mounting evidence that the concomitant inhibition of PAK1 enhances the potency of various anti-melanoma regimens. Overall, the available information suggests that a safe and effective inhibition of PAK1-dependent molecular processes would enhance the potency of the currently available anti-melanoma treatments, although considerable challenges in implementing such strategies still exist.

Recurrence Patterns for Regionally Metastatic Melanoma Treated in the Era of Adjuvant Therapy: A Systematic Review and Meta-Analysis

BACKGROUND

The purpose of this systematic review was to examine the timing and patterns of recurrence for patients with regionally metastatic melanoma on the basis of nodal management and receipt of adjuvant therapy.

METHODS

We identified randomized controlled trials and non-randomized studies published between 2010 and 2020 that reported timing and/or patterns of recurrence. We evaluated recurrence-free survival (RFS), location of recurrence, and surveillance strategy on the basis of receipt of adjuvant systemic therapy and nodal management with observation versus completion dissection. We compared differences in patterns of recurrence across studies using RevMan. RFS was evaluated graphically using point estimates and confidence intervals.

RESULTS

Among the 19 publications, there was wide variation in study populations, imaging surveillance regimens, and format of recurrence reporting. Patterns of disease recurrence did not differ between adjuvant and placebo/observation groups. A total of 11 studies reported RFS at variable time intervals, which ranged in adjuvant therapy groups (38-88% at 1 year, 29-67% at 2 years, 33-58% at 3 years, and 34-53% at 5 years) and placebo/observation groups (47-63% at 1 year, 39-47% at 2 years, 33-68% at 3 years, and 57% at 5 years). Anti-PD-1 immune therapy and BRAF/MEK inhibitor therapy were superior to placebo at year 1.

DISCUSSION

We found that adjuvant treatment improved RFS but did not alter the patterns of disease recurrence compared with patients managed without adjuvant systemic treatment. Future studies should separately report sites of disease recurrence on the basis of specific adjuvant systemic treatment and surveillance practices to better advise patients about their patterns and risk of recurrence.

Update on BRAF and MEK inhibition for treatment of melanoma in metastatic, unresectable, and adjuvant settings

INTRODUCTION

Selective inhibition of the MAPK pathway with BRAF and MEK inhibitors has emerged as a key component of the treatment of BRAF-mutant unresectable/locally advanced metastatic melanoma.

AREAS COVERED

Current data are presented on the efficacy and safety of BRAFi + MEKi combination therapy (dabrafenib/trametinib, vemurafenib/cobimetinib, and encorafenib/binimetinib) from phase I, II, and III trials in the unresectable/locally advanced metastatic setting, as well as neoadjuvant and adjuvant applications. The theoretical basis, pre-clinical findings, clinical trial results and current ongoing clinical studies of combined BRAF/MEK inhibition with immunotherapy, also known as 'triplet therapy,' are also explored.

EXPERT OPINION

Combination therapy with BRAF and MEK inhibitors dramatically improves response rates, progression-free survival and overall survival in patients with BRAF-mutant metastatic melanoma compared to historical treatments such as chemotherapy. Some serious adverse effects, including cutaneous squamous cell carcinoma, are attenuated with combination therapy, while less severe and reversible effects including pyrexia, left ventricular dysfunction, and ocular events can be more common with combination therapy. Existing data are insufficient to recommend triplet therapy, or a particular treatment sequence, with respect to BRAF and MEK inhibitors and immune therapies, though results from multiple ongoing trials are anticipated.

Anti-hepatocarcinoma activity of TT-1, an analog of melittin, combined with interferon-α via promoting the interaction of NKG2D and MICA

Hepatocarcinoma is one of the malignant cancers with significant morbidity and mortality. Immunotherapy has emerged in clinical treatment, owing to the limitation and severe side effects of chemotherapy. In the immune system, natural killer (NK) cells are important effectors required to eliminate malignant tumor cells without the limitation of major histocompatibility complex (MHC) molecule issues. Hence, treatment which could stimulate NK cells is of great interest. Here, we investigated the efficacy of the combined therapy of TT-1 (a mutant of melittin) and interferon-α (IFN-α) on NK cells and human liver cancer HepG-2/Huh7 cells in vitro and in vivo, as well as the mechanism involved. The combination therapy significantly inhibited the growth of HepG-2/Huh7 cells in vivo, but this effect was impaired after depleting NK cells. TT-1 not only up-regulated MHC class I-related chain molecules A (MICA) expression, but also prevented the secretion of soluble MICA (sMICA). Both the mRNA and protein of a disintegrin and metallopeptidase 10 (ADAM 10) in HepG-2/Huh7 cells were decreased after TT-1 treatment. The combined therapy of TT-1 and IFN-α could suppress the growth of HepG-2/Huh7 xenografted tumor effectively via promoting the interaction of NK group 2, member D (NKG2D) and MICA, indicating that TT-1+IFN-α would be a potential approach in treating liver cancer.

TT-1, an analog of melittin, triggers apoptosis in human thyroid cancer TT cells via regulating caspase, Bcl-2 and Bax

Melittin is a 26 amino acid residue antimicrobial peptide with known antitumor activity. In the present study, a novel peptide TT-1, derived from melittin and contained only 11 amino acids, was designed, and its antitumor effect was investigated. The present study is aimed to elucidate the effects and relative mechanisms of TT-1 on a human thyroid cancer cell line (TT) in vitro and in vivo. Cell viability assays, Annexin V/propidium iodide assays, western blotting and quantitative reverse transcription polymerase chain reaction were performed. Furthermore, a tumor-xenograft model was established to investigate the apoptotic mechanisms of TT-1 on TT cells. The results obtained indicated that TT-1 was able to suppress the proliferation of TT cells and exhibited low cytotoxicity to normal thyroid cells in vitro. The apoptotic rates of TT cells were also increased following TT-1 treatment. Additionally, TT-1 stimulated caspase-3, caspase-9 and Bax, and inhibited B-cell lymphoma 2 mRNA and protein expression. Finally, it was also demonstrated that TT-1 is able to markedly suppress tumor growth in a TT-bearing nude mouse model. In summary, TT-1 may inhibit the proliferation of TT cells by inducing apoptosis in vitro and in vivo, indicating that TT-1 may be a potential candidate for the treatment of thyroid cancer.

Hematological Effects, Serum, and Pulmonary Cytokine Profiles in a Melanoma Mouse Model Treated with GK1

OBJECTIVE

In a previous study, we demonstrated the therapeutic efficacy of a subcutaneous injection of GK1 peptide in a melanoma mouse model, effectively increasing the mean survival time by 42.58%, delaying tumor growth, and increasing intratumoral necrosis compared with the control. As a first approach to investigate the anti-melanoma effect of GK1, this study was carried out to determine the hematological effects along with both serum and lung cytokine profiles in a melanoma lung metastatic model.

MATERIALS AND METHODS

Thirteen C57BL6 female mice were transfected in the lateral tail vein with 2×10(5) B16-F0 melanoma cells. After 7 days, mice were separated in two different groups and treatments were initiated (day 0): The GK1-treated group (seven mice) were injected every 5 days intravenously with GK1 (10 μg) in the lateral tail vein, and the control group (six mice) were injected every 5 days with intravenous saline solution. Blood samples were collected every 5 days from day 0; tumor samples were obtained for cytokine measurements on the day of sacrifice.

RESULTS

In the peripheral blood, mice treated with GK1 presented a statistically significant decrease in IFN-γ (p<0.05), and lymphocytes tended to be lower compared with the control mice (p=0.06). Lung metastatic analysis demonstrated a significant increase in IFN-γ and IL-12p70 (p<0.05); a significant decrease in IL-17, IL-4, IL-22, IL-23, and IL-12p40 (p<0.05); and a marginal decrease in IL-1β (p=0.07) compared with the control.

DISCUSSION

Our results suggest that an intratumoral increase of cytokines with antitumor activity along with an intratumoral decrease of cytokines with protumor activity could explain, in part, the anti-melanoma effects of GK1 in a lung metastatic melanoma mouse model. Further studies must be performed to elucidate the precise mechanisms of action for GK1 peptide against melanoma, and their eventual application in humans.

BRAF and MEK inhibition in melanoma

INTRODUCTION

Selective inhibition of the MAPK pathway with either BRAF or MEK inhibition has emerged as a key component for the treatment of BRAF-mutant metastatic melanoma. New evidence suggests that the combination of BRAF and MEK inhibitors improves tumor response rate and progression-free survival, while potentially attenuating some of the serious adverse events observed with monotherapy.

AREAS COVERED

This review covers the current data on the efficacy and safety of the selective BRAF (vemurafenib and dabrafenib) and MEK (trametinib) inhibitors as well as the available data on BRAF inhibitor + MEK inhibitor combination therapy (dabrafenib + trametinib and vemurafenib + cobimetinib). The efficacy, safety and toxicity data are discussed from Phase I, Phase II and Phase III trials of these drugs.

EXPERT OPINION

Combination therapy with the BRAF and MEK inhibitors improves response rates and progression-free survival in patients with BRAF-mutant metastatic melanoma. Some of the serious adverse events, in particular, the incidence of cutaneous squamous cell carcinoma, are attenuated with combination therapy, whereas milder side effects such as pyrexia can be more common with combination therapy. Although dose reductions and dose interruptions are slightly more common with combination therapy, overall data supports the notion that combination therapy is safe and improves the outcomes for patients compared to single agent BRAF inhibitors.

The synthetic parasite-derived peptide GK1 increases survival in a preclinical mouse melanoma model

PURPOSE

The therapeutic efficacy of a synthetic parasite-derived peptide GK1, an immune response booster, was evaluated in a mouse melanoma model. This melanoma model correlates with human stage IIb melanoma, which is treated with wide surgical excision; a parallel study employing a surgical treatment was carried out as an instructive goal.

EXPERIMENTAL DESIGN

C57BL/6 mice were injected subcutaneously in the flank with 2×10(5) B16-F10 murine melanoma cells. When the tumors reached 20 mm3, mice were separated into two different groups; the GK1 group, treated weekly with peritumoral injections of GK1 (10 μg/100 μL of sterile saline solution) and the control group, treated weekly with an antiseptic peritumoral injection of 100 μL of sterile saline solution without further intervention. All mice were monitored daily for clinical appearance, tumor size, and survival. Surgical treatment was performed in parallel when the tumor size was 20 mm3 (group A), 500 mm3 (group B), and >500 mm3 (group C).

RESULTS

The GK1 peptide effectively increased the mean survival time by 9.05 days, corresponding to an increase of 42.58%, and significantly delayed tumor growth from day 3 to 12 of treatment. In addition, tumor necrosis was significantly increased (p<0.05) in the treated mice. The overall survival rates obtained with surgical treatment at 6 months were 83.33% for group A, 40% for group B, and 0% for group C, with significant differences (p<0.05) among the groups.

CONCLUSIONS

The GK1 peptide demonstrated therapeutic properties in a mouse melanoma model, as treatment resulted in a significant increase in the mean survival time of the treated animals (42.58%). The potential for GK1 to be used as a primary or adjuvant component of chemotherapeutic cocktails for the treatment of experimental and human cancers remains to be determined, and surgical removal remains a challenge for any new experimental treatment of melanoma in mouse models.

Effective melanoma immunotherapy with interleukin-2 delivered by a novel polymeric nanoparticle

Interleukin-2 (IL-2) has been shown to possess antitumor activity in numerous preclinical and clinical studies. However, the short half-life of recombinant IL-2 protein in serum requires repeated high-dose injections, resulting in severe side effects. Although adenovirus-mediated IL-2 gene therapy has shown antitumor efficacy, the host antibody response to adenoviral particles and potential biosafety concerns still obstruct its clinical applications. Here we report a novel nanopolymer for IL-2 delivery, consisting of low molecular weight polyethylenimine (600 Da) linked by β-cyclodextrin and conjugated with folate (named H1). H1 was mixed with IL-2 plasmid to form H1/pIL-2 polyplexes of around 100 nm in diameter. Peritumoral injection of these polyplexes suppressed the tumor growth and prolonged the survival of C57/BL6 mice bearing B16-F1 melanoma grafts. Importantly, the antitumor effects of H1/pIL-2 (50 μg DNA) were similar to those of recombinant adenoviruses expressing IL-2 (rAdv-IL-2; 2 × 10(8) pfu). Furthermore, we showed that H1/pIL-2 stimulated the activation and proliferation of CD8+, CD4+ T cell, and natural killer cells in peripheral blood and increased the infiltration of CD8+, CD4+ Tcells, and natural killer cells into the tumor environment. In conclusion, these results show that H1/pIL-2 is an effective and safe melanoma therapeutic with an efficacy comparable to that of rAdv-IL-2. This treatment represents an alternative gene therapy strategy for melanoma.

Inhibition of melanoma growth by subcutaneous administration of hTERTC27 viral cocktail in C57BL/6 mice

Background

hTERTC27 is a 27 kDa C-terminal polypeptide of human telomerase reverse transcriptase that has previously been shown to reduce tumorigenicity of HeLa cells and suppress growth of xenografted glioblastoma in nude mice. Although ectopic expression of hTERTC27 upregulated genes that are involved in apoptosis, cell cycle, and immune response, the mechanism for hTERTC27-induced tumor suppression has not been completely elucidated. Since hTERT was identified as a universal tumor-associated antigen, we hypothesize that hTERTC27 inhibits tumor growth in vivo through activation of anti-tumor immune response.

Methodology/Principal Finding

Immunocopetent C57BL/6 mice were used for mouse B16 melanoma model. Mice bearing B16 melanoma were administered rAAV-/rAdv viral cocktail expressing hTERTC27, and tumor growth was monitored after viral cocktail treatment. Blood and splenocytes were used to determine the level of cytokines and the activity of immune cells, respectively. B16 tumor growth was significantly inhibited by subcutaneous administration of a single dose of 1.5×10¹¹ vg rAAV-hTERTC27 and 2.5×10⁹ pfu rAdv-hTERTC27 viral cocktail (rAAV-/rAdv-hTERTC27). The population and cytotoxicity of NK cells in the mice were significantly augmented by rAAV-/rAdv-hTERTC27 treatment, and selective depletion of the NK cell population in mice by intraperitoneal injection of anti-GM1 antibody abrogated the growth suppression of melanoma induced by rAAV-/rAdv-hTERTC27 administration.

Conclusion

Activation of NK cells by administration of rAAV-/rAdv-hTERTC27 is critical for growth suppression of melanoma in mouse model.

Effect of DNA repair host factors on temozolomide or dacarbazine melanoma treatment in Caucasians

OBJECTIVES

The efficacy of temozolomide (TMZ) or dacarbazine (DTIC) in melanoma treatment depends on low O-6-methylguanine-DNA-methyltransferase (MGMT) repair and on high mismatch repair. The aim of this study was to identify individual host markers for hematologic side effects and the treatment efficacy of TMZ or DTIC in melanoma treatment.

METHODS

Fifty-one Caucasian patients with metastasized melanoma were recruited. In each patient, the mRNA expression of MGMT and two essential mismatch repair genes, MLH1 and MSH2, was measured in peripheral blood. The coding gene regions, including splice sites, were sequenced to identify genetic variants, and the promoter methylation status of the genes was determined.

RESULTS

Both constitutively low and high mRNA expression of MGMT, MLH1, and MSH2 were significantly associated with reduced hematologic side effects (P = 0.008-0.020), but did not correlate with treatment efficacy. We identified five variants in the MGMT gene, 13 variants in MLH1, and seven variants in MSH2, including five novel genetic variants in MLH1. Variations of the hosts' gene expression of MGMT, MLH1, and MSH2 did not result from promoter methylation. Of note, one variant in MSH2 (rs2303428) was associated with increased hematologic side effects and showed a tendency for better treatment response.

CONCLUSION

Our results indicate that either low or high host expression of MGMT, MLH1, and MSH2 may serve as a marker for reduced hematologic side effects of TMZ or DTIC, but not for treatment efficacy in melanoma. The genetic variant rs2303428 (MSH2) might serve as a predictive marker for hematologic side effects and treatment response.

Topical CpG enhances the response of murine malignant melanoma to dacarbazine

Malignant melanoma is a potentially fatal skin cancer that is increasing in incidence. Standard chemoimmunotherapy consisting of dacarbazine (DTIC) given with IFN-alpha has had disappointing results. We describe a chemoimmunotherapy protocol for cutaneous melanoma that combines the administration of DTIC with the topical application of CpG oligodinucleotide (ODN). Subcutaneous B16 melanoma tumors in C57BL/6 mice were treated with intraperitoneal injections of DTIC followed by the topical application of CpG-ODN over the tumors. This therapeutic approach abrogated the growth of established tumors and significantly enhanced survival. Topical CpG application was more effective than intratumoral CpG. Cell depletion studies indicated that the antitumor effect was dependent on both CD4(+) and CD8(+) cells but not on natural killer (NK) cells. Tumor-specific cytotoxic T-lymphocyte activity was generated in treated animals and was highest in topically treated animals. Immunohistochemical analysis revealed that DTIC, but not CpG, enhanced tumor cell apoptosis. Further, topical CpG induced an expansion of a B220(+)CD8(+) subset of dendritic cells and a subset of NK1.1(+) CD11c(+) cells within the tumors. By enhancing both tumor cell death and local immune activation, DTIC/topical CpG chemoimmunotherapy induced an effective T-cell-dependent host-immune response against melanoma.

Nursing Care of Patients Receiving High-Dose, Continuous-Infusion Interleukin-2 With Pulse Dose and Famotidine

High-dose, continuous-infusion interleukin-2 (IL-2) followed by pulse dose and concurrent administration of famotidine has demonstrated response rates of 64% and 33% in patients with metastatic melanoma and metastatic renal cell carcinoma, respectively. Currently, no information is available concerning the nursing care of patients receiving that IL-2 regimen. Given the high response rates of patients on the treatment, attention by the nursing profession is warranted. Effective nursing care of patients receiving IL-2 is essential to the regimen's success. Recognition and prompt treatment of common side effects lead to better patient outcomes. This article provides nurses with an overview of the treatment regimen, expected side effects, psycho-social considerations, and discharge instructions for patients receiving continuous-infusion plus pulse IL-2 and famotidine.

The multikinase inhibitor midostaurin (PKC412A) lacks activity in metastatic melanoma: a phase IIA clinical and biologic study

Midostaurin (PKC412A), N-benzoyl-staurosporine, potently inhibits protein kinase C alpha (PKCalpha), VEGFR2, KIT, PDGFR and FLT3 tyrosine kinases. In mice, midostaurin slows growth and delays lung metastasis of melanoma cell lines. We aimed to test midostaurin's safety, efficacy and biologic activity in a Phase IIA clinical trial in patients with metastatic melanoma. Seventeen patients with advanced metastatic melanoma received midostaurin 75 mg p.o. t.i.d., unless toxicity or disease progression supervened. Patient safety was assessed weekly, and tumour response was assessed clinically or by CT. Tumour biopsies and plasma samples obtained at entry and after 4 weeks were analysed for midostaurin concentration, PKC activity and multidrug resistance. No tumour responses were seen. Two (12%) patients had stable disease for 50 and 85 days, with minor response in one. The median overall survival was 43 days. Seven (41%) discontinued treatment with potential toxicity, including nausea, vomiting, diarrhoea and/or fatigue. One patient had >50% reduction in PKC activity. Tumour biopsies showed two PKC isoforms relatively insensitive to midostaurin, out of three patients tested. No modulation of multidrug resistance was demonstrated. At this dose schedule, midostaurin did not show clinical or biologic activity against metastatic melanoma. This negative trial reinforces the importance of correlating biologic and clinical responses in early clinical trials of targeted therapies.

Novel Imaging Techniques in Melanoma

Cutaneous melanoma is one of the most deadly malignancies. Although it accounts for approximately 4% of all cancer cases, it ac-counts for approximately 79% of skin cancer-related deaths. In the past few years, the nuclear medicine platform used in the management of melanoma has extended to biochemical and structural imaging. In clinical practice, integrated positron emission tomography/CT devices allow anatomic and metabolic characterization of meta-static disease in a single study. Similarly, more accurate localization of sentinel nodes in a 3-D space now is feasible with hybrid single photon emission CT/CT system. In translational research, [18F]fluorodeoxyglucose probes have been designed to optimize the detection of melanoma tumor sites in vivo.

Re-evaluating the role of dacarbazine in metastatic melanoma: what have we learned in 30 years?

Since dacarbazine was approved for treating metastatic melanoma in the 1970s, numerous studies have evaluated whether different schedules and dacarbazine-based combinations improve clinical outcomes. This evidence-based review shows that combining dacarbazine with other drugs having single-agent activity and/or hormonal or immunotherapeutic compounds fails to provide clinically meaningful improvements in survival, and may increase toxicity. In patients with metastatic melanoma, dacarbazine was previously administered in cycles of multiple consecutive daily infusions per cycle. The introduction of potent antiemetics, together with concerns relating to patient comfort and clinic utilisation time, has enabled regimens involving single-dose dacarbazine, administered at the same total dose per cycle. These appear to be as effective as multiple-dose schedules, are well tolerated, and are more straightforward to administer. Single-administration dacarbazine (850-1000 mg/m2), once every 3 weeks, is currently the standard reference therapy in patients with advanced melanoma. New effective therapies are urgently needed for this treatment-refractory disease.

Kaposi's sarcoma as a model for cancer immunotherapy

Physicians have, for over a century, attempted to harness the potential therapeutic power of the immune system to treat patients with cancer. The discovery that cancer regression can be achieved by immune rejection of tumour antigens theoretically allows the eradication of neoplastic cells without toxicity to normal tissues. An understanding of the mode of presentation of tumour antigens, including those complexed to heat shock proteins by major histocompatibility complex (MHC) class I and class II molecules, and their recognition by CD8(+) and CD4(+) T cells, respectively, has further delineated the potential cancer rejection pathways involved. This also enables the sustained induction and expansion of specific anti-tumour T cells with cytolytic activity.

Future perspectives on malignant melanoma

Emphasis for the treatment of melanoma should be shifted more to prevention and early diagnosis, because early melanoma may potentially be cured in most cases. Clinical trials are important to establish more effective adjuvant modalities against melanoma. Multifaceted aspects of micrometastasis, including differentiation of different clones with respect to the primary tumor, acquisition of adhesion molecules, and host interaction with the microscopic tumor, will shed new light on the biology and mechanism of early metastasis. New molecular and genetic tools may be used to dissect the mechanisms of lymphatic and hematogenous routes of metastasis. If such mechanisms can be understood, potential therapeutic maneuvers can be developed to prevent the process of micrometastasis.