Melanoma

Comparison of Single-Photon Emission Computed Tomography-Computed Tomography (SPECT/CT) and Conventional Planar Lymphoscintigraphy for Sentinel Node Localization in Patients with Cutaneous Malignancies

BACKGROUND

Accurate preoperative lymphoscintigraphy is vital to performing sentinel lymph node biopsy (SLNB) for cutaneous malignancies. Potential advantages of single-photon emission computed tomography with integrated computed tomography (SPECT/CT) include the ability to readily identify aberrant drainage patterns as well as provide the surgeon with three-dimensional anatomic landmarks not seen on conventional planar lymphoscintigraphy (PLS).

METHODS

Patients with cutaneous malignancies who underwent SLNB with preoperative imaging using both SPECT/CT and PLS from 2011 to 2014 were identified.

RESULTS

Both SPECT/CT and PLS were obtained in 351 patients (median age, 69 years; range, 5-94 years) with cutaneous malignancies (melanoma = 300, Merkel cell carcinoma = 33, squamous cell carcinoma = 8, other = 10) after intradermal injection of ^99mtechnetium sulfur colloid (median dose 300 µCi). A mean of 4.3 hot spots were identified on SPECT/CT compared to 3.0 on PLS (p < 0.001). One hundred fifty-three patients (43.6 %) had identical findings between SPECT/CT and PLS, while 172 (49 %) had additional hot spots identified on SPECT/CT compared to only 24 (6.8 %) additional on PLS. SPECT/CT demonstrated additional nodal basins in 103 patients (29.4 %), compared to only 11 patients (3.1 %) with additional basins on PLS.

CONCLUSIONS

SPECT/CT is a useful adjunct that can help with sentinel node localization in challenging cases. It identified additional hot spots not seen on PLS in almost 50 % of patients. Because PLS identified hot spots not seen on SPECT/CT in 6.8 % of patients, we recommend using both modalities jointly. Long-term follow-up will be required to validate the clinical significance of the additional hot spots identified by SPECT/CT.

Checkpoint inhibitors in chronic kidney failure and an organ transplant recipient

BACKGROUND

Immune-checkpoint inhibitors have been approved for the treatment of metastatic melanoma based on several phase III trials. Patients after organ transplantation and patients with impaired renal function were excluded from these studies. Recently, allograft rejections were reported in organ transplant recipients receiving PD-1 blocking antibodies.

PATIENTS AND FINDINGS

Four patients with metastatic melanoma and impaired kidney function (baseline serum creatinine 1.79-2.59 mg/dl) were treated with immune-checkpoint blockers, of which one was a kidney-transplant recipient receiving immunosuppressive therapy with tacrolimus and prednisolone. The patient was initially treated with the anti-CTLA-4 antibody ipilimumab after detailed explanation of the potential risk of allograft rejection. Upon disease progression, therapy was switched to the anti-PD-1 antibody nivolumab. The other three patients were treated with nivolumab or pembrolizumab, two of them after previous therapy with ipilimumab.

RESULTS

The patients received a median of six doses (range 3-21) of anti-PD-1 antibodies and 3-4 doses of ipilimumab. Kidney function tests remained stable throughout the course of checkpoint blockade. In the kidney transplant recipient, neither ipilimumab nor nivolumab led to an allograft rejection. Responses to anti-PD-1 treatment were divergent with two patients showing disease progression, one achieving a mixed response and one experiencing a complete response.

CONCLUSION

These cases show that checkpoint inhibitors can be a safe therapeutic option in patients with impaired kidney function. Furthermore, we report the first organ transplant patient with malignant melanoma who received ipilimumab followed by nivolumab without experiencing a kidney allograft rejection.

Melanoma Brain Metastasis: Mechanisms, Models, and Medicine

The development of brain metastases in patients with advanced stage melanoma is common, but the molecular mechanisms responsible for their development are poorly understood. Melanoma brain metastases cause significant morbidity and mortality and confer a poor prognosis; traditional therapies including whole brain radiation, stereotactic radiotherapy, or chemotherapy yield only modest increases in overall survival (OS) for these patients. While recently approved therapies have significantly improved OS in melanoma patients, only a small number of studies have investigated their efficacy in patients with brain metastases. Preliminary data suggest that some responses have been observed in intracranial lesions, which has sparked new clinical trials designed to evaluate the efficacy in melanoma patients with brain metastases. Simultaneously, recent advances in our understanding of the mechanisms of melanoma cell dissemination to the brain have revealed novel and potentially therapeutic targets. In this review, we provide an overview of newly discovered mechanisms of melanoma spread to the brain, discuss preclinical models that are being used to further our understanding of this deadly disease and provide an update of the current clinical trials for melanoma patients with brain metastases.

Wnt Signaling in Cell Motility and Invasion: Drawing Parallels between Development and Cancer

The importance of canonical and non-canonical Wnt signal transduction cascades in embryonic development and tissue homeostasis is well recognized. The aberrant activation of these pathways in the adult leads to abnormal cellular behaviors, and tumor progression is frequently a consequence. Here we discuss recent findings and analogies between Wnt signaling in developmental processes and tumor progression, with a particular focus on cell motility and matrix invasion and highlight the roles of the ARF (ADP-Ribosylation Factor) and Rho-family small GTP-binding proteins. Wnt-regulated signal transduction from cell surface receptors, signaling endosomes and/or extracellular vesicles has the potential to profoundly influence cell movement, matrix degradation and paracrine signaling in both development and disease.

Melanomas prevent endothelial cell death under restrictive culture conditions by signaling through AKT and p38 MAPK/ ERK-1/2 cascades

Although melanoma progression and staging is clinically well characterized, a large variation is observed in pathogenesis, progression, and therapeutic responses. Clearly, intrinsic characteristics of melanoma cells contribute to this variety. An important factor, in both progression of the disease and response to therapy, is the tumor-associated vasculature. We postulate that melanoma cells communicate with endothelial cells (ECs) in order to establish a functional and supportive blood supply. We investigated the angiogenic potential of human melanoma cell lines by monitoring the survival of ECs upon exposure to melanoma conditioned medium (CM), under restrictive conditions. We observed long-term (up to 72 h) EC survival under hypoxic conditions upon treatment with all melanoma CMs. No such survival effect was observed with the CM of melanocytes. The CM of pancreatic and breast tumor cell lines did not show a long-term survival effect, suggesting that the survival factor is specific to melanoma cells. Furthermore, all size fractions (up to < 1 kDa) of the melanoma CM induced long-term survival of ECs. The survival effect observed by the < 1 kDa fraction excludes known pro-angiogenic factors. Heat inactivation and enzymatic digestion of the CM did not inactivate the survival factor. Global gene expression and pathway analysis suggest that this effect is mediated in part via the AKT and p38 MAPK/ ERK-1/2 signaling axis. Taken together, these data indicate the production of (a) survival factor/s (< 1 kDa) by melanoma cell lines, which enables long-term survival of ECs and promotes melanoma-induced angiogenesis.

Signaling Pathways in Melanogenesis

Melanocytes are melanin-producing cells found in skin, hair follicles, eyes, inner ear, bones, heart and brain of humans. They arise from pluripotent neural crest cells and differentiate in response to a complex network of interacting regulatory pathways. Melanins are pigment molecules that are endogenously synthesized by melanocytes. The light absorption of melanin in skin and hair leads to photoreceptor shielding, thermoregulation, photoprotection, camouflage and display coloring. Melanins are also powerful cation chelators and may act as free radical sinks. Melanin formation is a product of complex biochemical events that starts from amino acid tyrosine and its metabolite, dopa. The types and amounts of melanin produced by melanocytes are determined genetically and are influenced by a variety of extrinsic and intrinsic factors such as hormonal changes, inflammation, age and exposure to UV light. These stimuli affect the different pathways in melanogenesis. In this review we will discuss the regulatory mechanisms involved in melanogenesis and explain how intrinsic and extrinsic factors regulate melanin production. We will also explain the regulatory roles of different proteins involved in melanogenesis.

The heterogeneity of store-operated calcium entry in melanoma

Calcium is a key regulator of many physiological processes that are perturbed in cancer, such as migration, proliferation and apoptosis. The proteins STIM and Orai mediate store-operated calcium entry (SOCE), the main pathway for calcium entry in non-excitable cells. Changes in the expression and function of STIM and Orai have been found in a range of cancer types and thus implicated in disease progression. Here we discuss the role of STIM, Orai and the SOCE pathway in the progression of melanoma and explore how the heterogeneous nature of melanoma may explain the lack of consensus in the field regarding the role of SOCE in the progression of this disease.

Research projects in the Surgeon-Scientist and Clinician-Investigator programs at the University of Toronto (1987-2016): a cohort study

BACKGROUND

Physicians have traditionally been at the forefront of medical research, bringing clinical questions to the laboratory and returning with ideas for treatment. However, we have anecdotally observed a decline in the popularity of basic science research among trainees. We hypothesized that fewer resident physicians have been pursuing basic science research training over time.

METHODS

We examined records from residents in the Surgeon-Scientist and Clinician-Investigator programs at the University of Toronto (1987-2016). Research by residents was categorized independently by 2 raters as basic science, clinical epidemiology or education-related based on the title of the project, the name of the supervisor and Pubmed searches. The study population was divided into quintiles of time, and the proportion pursuing basic science training in each quintile was calculated.

RESULTS

Agreement between the raters was 100%; the categorization of the research topic remained unclear in 9 cases. The proportion of trainees pursuing basic science training dropped by 60% from 1987 to 2016 (p = 0.005).

INTERPRETATION

Significantly fewer residents in the Surgeon-Scientist and Clinician-Investigator Programs at the University of Toronto are pursuing training in the basic sciences as compared with previous years.

Let’s rethinking about the safety of phosphodiesterase type 5 inhibitor in the patients with erectile dysfunction after radical prostatectomy

As the radical prostatectomy (RP) for the patient diagnosed as localized prostate cancer has been increasing, erectile dysfunction (ED) associated with RP is increased and ED after RP is a significant risk factor to reduce the quality of life for the patient after RP. Therefore, the treatment concept called penile rehabilitation was introduced and phosphodiesterase type 5 inhibitor (PDE5I) is used widely for the prostate cancer patient after RP. Generally PDE5I is considered as safe and effective drug for the prostate cancer patient after RP. Recently, a report against the general opinion that PDE5I use is safe in the patient with prostate cancer was reported and the analysis of 5-yr biochemical recurrence-free survival after RP between the PDE5I users and non-PDE5I users after bilateral nerve sparing RP showed decreased 5-yr biochemical recurrence-free survival in the PDE5I users. In addition, a longitudinal cohort study reported that sildenafil, a kind of PDE5I, use might be associated with the development of melanoma and this result suggested the possibility of adverse effect of PDE5I on some kinds of cancers as well as prostate cancer. Moreover, the studies to evaluate the influence of nitric oxide (NO) and guanosine monophosphate (cGMP) signaling pathway associated with PDE5 showed both cancer reduction and cancer development. Therefore, the role of NO and cGMP signaling pathway in cancer was reviewed based on the previous studies and suggested the necessity of further clinical studies concerning about the safety of PDE5I in prostate cancer.

Nivolumab in combination with ipilimumab for the treatment of melanoma

Melanoma patients develop resistance to most therapies, including chemo- and targeted-therapy drugs. Single-agent therapies are ineffective due to the heterogeneous nature of tumors comprising several subpopulations. Treatment of melanoma with immune-based therapies such as anti-cytotoxic T-lymphocyte activation-4 and anti-programmed death-1 antibodies has shown modest but long-lasting responses. Unfortunately, only subsets of melanoma patients respond to antibody-based therapies. Heterogeneity in lymphocyte infiltration and low frequency of anti-melanoma-reactive T-cells in tumor lesions are partly responsible for a lack of response to antibody-based therapies. Both antibodies have same biological function but they bind to different ligands at various phases of T-cell activity. Thus, combination therapy of antibodies has shown superior response rates than single-agent therapy. However, toxicity is a cause of concern in these therapies. Future identification of therapy-response biomarkers, mobilization of tumor-reactive T-cell infiltration using cancer vaccines, or non-specific targeted-therapy drugs will minimize toxicity levels and provide long-term remissions in melanoma patients.

Computational modeling in melanoma for novel drug discovery

INTRODUCTION

There is a growing body of evidence highlighting the applications of computational modeling in the field of biomedicine. It has recently been applied to the in silico analysis of cancer dynamics. In the era of precision medicine, this analysis may allow the discovery of new molecular targets useful for the design of novel therapies and for overcoming resistance to anticancer drugs. According to its molecular behavior, melanoma represents an interesting tumor model in which computational modeling can be applied. Melanoma is an aggressive tumor of the skin with a poor prognosis for patients with advanced disease as it is resistant to current therapeutic approaches.

AREAS COVERED

This review discusses the basics of computational modeling in melanoma drug discovery and development. Discussion includes the in silico discovery of novel molecular drug targets, the optimization of immunotherapies and personalized medicine trials.

EXPERT OPINION

Mathematical and computational models are gradually being used to help understand biomedical data produced by high-throughput analysis. The use of advanced computer models allowing the simulation of complex biological processes provides hypotheses and supports experimental design. The research in fighting aggressive cancers, such as melanoma, is making great strides. Computational models represent the key component to complement these efforts. Due to the combinatorial complexity of new drug discovery, a systematic approach based only on experimentation is not possible. Computational and mathematical models are necessary for bringing cancer drug discovery into the era of omics, big data and personalized medicine.

The role of Orai-STIM calcium channels in melanocytes and melanoma

Calcium signalling within normal and cancer cells regulates many important cellular functions such as migration, proliferation, differentiation and cytokine secretion. Store operated Ca(2+) entry (SOCE) via the Ca(2+) release activated Ca(2+) (CRAC) channels, which are composed of the plasma membrane based Orai channels and the endoplasmic reticulum stromal interaction molecules (STIMs), is a major Ca(2+) entry route in many cell types. Orai and STIM have been implicated in the growth and metastasis of multiple cancers; however, while their involvement in cancer is presently indisputable, how Orai-STIM-controlled Ca(2+) signals affect malignant transformation, tumour growth and invasion is not fully understood. Here, we review recent studies linking Orai-STIM Ca(2+) channels with cancer, with a particular focus on melanoma. We highlight and examine key molecular players and the signalling pathways regulated by Orai and STIM in normal and malignant cells, we expose discrepancies, and we reflect on the potential of Orai-STIMs as anticancer drug targets. Finally, we discuss the functional implications of future discoveries in the field of Ca(2+) signalling.

Combination with γ-secretase inhibitor prolongs treatment efficacy of BRAF inhibitor in BRAF-mutated melanoma cells

Oncogenic triggering of the MAPK pathway in melanocytes results in senescence, and senescence escape is considered as one critical step for melanocytic transformation. In melanoma, induction of a senescent-like state by BRAF-inhibitors (BRAFi) in a fraction of treated cells - instead of killing - contributes to the repression of tumor growth, but may also provide a source for relapse. Here, we demonstrate that NOTCH activation in melanocytes is not only growth-promoting but it also protects these cells against oncogene-induced senescence. In turn, treatment of melanoma cells with an inhibitor of the NOTCH-activating enzyme γ-secretase led to induction of a senescent-like status in a fraction of the cells but overall achieved only a moderate inhibition of melanoma cell growth. However, combination of γ-secretase inhibitor (GSI) with BRAFi markedly increased the treatment efficacy particularly in long-term culture. Moreover, even melanoma cells starting to regrow after continuous BRAFi treatment - the major problem of BRAFi therapy in patients - can still be affected by the combination treatment. Thus, combining GSI with BRAFi increases the therapeutic efficacy by, at least partially, prolonging the senescent-like state of treated cells.

Nifuroxazide exerts potent anti-tumor and anti-metastasis activity in melanoma

Melanoma is a highly malignant neoplasm of melanocytes with considerable metastatic potential and drug resistance, explaining the need for new candidates that inhibit tumor growth and metastasis. The signal transducer and activator of the transcription 3 (Stat3) signaling pathway plays an important role in melanoma and has been validated as promising anticancer target for melanoma therapy. In this study, nifuroxazide, an antidiarrheal agent identified as an inhibitor of Stat3, was evaluated for its anti-melanoma activity in vitro and in vivo. It had potent anti-proliferative activity against various melanoma cell lines and could induce G2/M phase arrest and cell apoptosis. Moreover, nifuroxazide markedly impaired melanoma cell migration and invasion by down-regulating phosphorylated-Src, phosphorylated-FAK, and expression of matrix metalloproteinase (MMP) -2, MMP-9 and vimentin. It also significantly inhibited tumor growth without obvious side effects in the A375-bearing mice model by inducing apoptosis and reducing cell proliferation and metastasis. Notably, nifuroxazide significantly inhibited pulmonary metastases, which might be associated with the decrease of myeloid-derived suppressor cells (MDSCs). These findings suggested that nifuroxazide might be a potential agent for inhibiting the growth and metastasis of melanoma.

Boron neutron capture therapy for malignant melanoma: first clinical case report in China

A phase I/II clinical trial for treating malignant melanoma by boron neutron capture therapy (BNCT) was designed to evaluate whether the world’s first in-hospital neutron irradiator (IHNI) was qualified for BNCT. In this clinical trial planning to enroll 30 patients, the first case was treated on August 19, 2014. We present the protocol of this clinical trial, the treating procedure, and the clinical outcome of this first case. Only grade 2 acute radiation injury was observed during the first four weeks after BNCT and the injury healed after treatment. No late radiation injury was found during the 24-month follow-up. Based on positron emission tomography-computed tomography (PET/CT) scan, pathological analysis and gross examination, the patient showed a complete response to BNCT, indicating that BNCT is a potent therapy against malignant melanoma and IHNI has the potential to enable the delivery of BNCT in hospitals.

Heterogeneity in Melanoma

Melanoma is among the most aggressive and therapy-resistant human cancers. While great strides in therapy have generated enthusiasm, many challenges remain. Heterogeneity is the most pressing issue for all types of therapy. This chapter summarizes the clinical classification of melanoma, of which the research community now adds additional layers of classifications for better diagnosis and prediction of therapy response. As the search for new biomarkers increases, we expect that biomarker analyses will be essential for all clinical trials to better select patient populations for optimal therapy. While individualized therapy that is based on extensive biomarker analyses is an option, we expect in the future genetic and biologic biomarkers will allow grouping of melanomas in such a way that we can predict therapy outcome. At this time, tumor heterogeneity continues to be the major challenge leading inevitably to relapse. To address heterogeneity therapeutically, we need to develop complex therapies that eliminate the bulk of the tumor and, at the same time, the critical subpopulations.

Genomic correlates of response to CTLA-4 blockade in metastatic melanoma

Monoclonal antibodies directed against cytotoxic T lymphocyte-associated antigen-4 (CTLA-4), such as ipilimumab, yield considerable clinical benefit for patients with metastatic melanoma by inhibiting immune checkpoint activity, but clinical predictors of response to these therapies remain incompletely characterized. To investigate the roles of tumor-specific neoantigens and alterations in the tumor microenvironment in the response to ipilimumab, we analyzed whole exomes from pretreatment melanoma tumor biopsies and matching germline tissue samples from 110 patients. For 40 of these patients, we also obtained and analyzed transcriptome data from the pretreatment tumor samples. Overall mutational load, neoantigen load, and expression of cytolytic markers in the immune microenvironment were significantly associated with clinical benefit. However, no recurrent neoantigen peptide sequences predicted responder patient populations. Thus, detailed integrated molecular characterization of large patient cohorts may be needed to identify robust determinants of response and resistance to immune checkpoint inhibitors.

Genomic correlates of response to CTLA-4 blockade in metastatic melanoma

Monoclonal antibodies directed against cytotoxic T lymphocyte-associated antigen-4 (CTLA-4), such as ipilimumab, yield considerable clinical benefit for patients with metastatic melanoma by inhibiting immune checkpoint activity, but clinical predictors of response to these therapies remain incompletely characterized. To investigate the roles of tumor-specific neoantigens and alterations in the tumor microenvironment in the response to ipilimumab, we analyzed whole exomes from pretreatment melanoma tumor biopsies and matching germline tissue samples from 110 patients. For 40 of these patients, we also obtained and analyzed transcriptome data from the pretreatment tumor samples. Overall mutational load, neoantigen load, and expression of cytolytic markers in the immune microenvironment were significantly associated with clinical benefit. However, no recurrent neoantigen peptide sequences predicted responder patient populations. Thus, detailed integrated molecular characterization of large patient cohorts may be needed to identify robust determinants of response and resistance to immune checkpoint inhibitors.

Novel Therapies for Metastatic Melanoma: An Update on Their Use in Older Patients

Cutaneous melanoma is the most aggressive form of skin cancer. With age as a risk factor, melanoma is projected to become a substantial healthcare burden. The clinical course of melanoma in older patients is different from that in middle-aged and younger patients: melanomas are thicker, have higher mitotic rates and are more likely to be ulcerated. Older patients also have a higher mortality rate, yet, paradoxically, have a lower rate of lymph node metastases. After decades of no significant progress in the treatment of this devastating disease, novel insights into the mechanisms underlying the pathophysiology of metastatic melanoma have led to new and remarkably efficient therapeutic opportunities. The discovery that about half of all melanomas carry BRAF mutations led to the introduction of targeted therapy with significant improvements in clinical outcomes. Although these drugs appear to be equally effective in older patients, specific considerations regarding adverse events are required. Besides targeted therapy, immunotherapy has emerged as an alternative therapeutic option. Antibodies that block cytotoxic T-lymphocyte antigen 4 (CTLA-4) and programmed cell death protein 1 (PD-1) can induce responses with high durability. Despite an aging immune system, older patients seem to benefit to the same degree from these treatments, apparently without increased toxicity. In this review, we focus on the epidemiology, clinicopathological features, and recent developments of systemic treatment in cutaneous melanoma with regard to older patients.