Malignant melanoma in the 21st century, part 2: staging, prognosis, and treatment

Photothermal therapy improves the efficacy of topical immunotherapy against melanoma

BACKGROUND

Melanoma is an aggressive cancer with poor response to traditional therapies. A combination of photothermal therapy and topical immunotherapy may enhance elimination of melanoma..

MATERIALS AND METHODS

C57BL/6 mice with early stage and metastatic melanoma were treated with laser immunotherapy (LIT), combining near-infrared laser-based photothermal therapy (PTT) and topical imiquimod (IMQ)-based immunotherapy. The volume of primary and abscopal melanoma, animal survival, tissue temperature, transcriptome, and immune cell response were investigated to evaluate the effect of LIT.

RESULTS

LIT could eliminate primary tumors, inhibite abscopal tumors, and prolong animal survival. The tumor tissues were selectively destroyed under a photothermal gradient between 38.2 ± 3.7 °C and 73.0 ± 2.3 °C. Gene expression analysis showed a significant increase in the expression of damage associated molecular patterns. Additionally, the population of mature dendritic cells, CD4+ T cells, and CD8+ T cells were increased, while myeloid-derived suppressor cells were downregulated after LIT.

CONCLUSION

The study showed that LIT inhibited the growth of both primary and abscopal melanoma by activating systemic antitumor immune responses and reversing the immunosuppressive tumor microenvironment, making LIT a potential method for advanced melanoma treatment.

Clinicopathological characteristics and prognosis in significantly thick acral lentiginous melanoma in Taiwan

This retrospective cohort study enrolled 385 patients diagnosed with cutaneous melanoma from 1980 to 2021 in National Taiwan University Hospital (NTUH). The aim of this study was to investigate the relationship between thickness of primary melanoma lesions and disease outcome of melanoma patients, in particular, those diagnosed with acral lentiginous melanoma (ALM). The association between important clinicopathological characteristics other than tumor thickness and disease outcome was also analyzed. Survival analyses with the Kaplan-Meier method were utilized to investigate the prognoses of patients with different lesion thickness. The male-to-female ratio was 1.12:1. The median age at diagnosis was 63 years old (mean: 62.2 years). There were 283 cases (73.5%) of acral lentiginous melanoma (ALM) with a male-to-female ratio of 1.04:1. Between patients with primary ALM lesions 4.1 millimeters (mm) to 8.0 mm thick and those with lesions over 8.0 mm thick, significant differences in prognostic outcomes including incidence of second recurrences within 1 year (raw p = 0.003, Bonferroni corrected p = 0.009) and distant metastases within 1 year (raw p = 0.003, Bonferroni corrected p = 0.008), were observed. Significantly worse 1-year (raw p = 0.01, Bonferroni corrected p=0.03) and 2-year survival (raw p = 0.006, Bonferroni corrected p = 0.02) were found in ALM patients with lesions of over 8 mm thick than those with lesions 4.1 mm to 8.0 mm at diagnosis. Vigilant short-term follow-up is warranted in ALM patients with lesions of over 8.0 mm thick at diagnosis due to higher risks of adverse outcome.

Validation of the American Joint Committee on Cancer Eighth Edition Staging of Patients With Metastatic Cutaneous Melanoma Treated With Immune Checkpoint Inhibitors

IMPORTANCE

Immune checkpoint inhibitors (ICIs) have transformed the survival of patients with metastatic melanoma. Patient prognosis is reflected by the American Joint Committee on Cancer (AJCC) staging system; however, it is unknown whether the metastatic (M) stage categories for cutaneous melanoma remain informative of prognosis in patients who have received ICIs.

OBJECTIVES

To evaluate the outcomes of patients with metastatic cutaneous melanoma based on the M stage category from the AJCC eighth edition and to determine whether these designations continue to inform the prognosis of patients who have received ICIs.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study included patients with metastatic cutaneous melanoma who were treated between August 2006 and August 2019 at the University of Michigan. The estimated median follow-up time was 35.5 months. Patient data were collected via the electronic medical record system. Critical findings were externally validated in a multicenter nationwide cohort of patients treated within the Veterans Affairs health care system. Data analysis was conducted from February 2020 to January 2021.

EXPOSURES

All patients were treated with dual-agent concurrent ipilimumab and nivolumab followed by maintenance nivolumab or single-agent ipilimumab, nivolumab, or pembrolizumab therapy. Patients were staged using the AJCC eighth edition.

MAIN OUTCOMES AND MEASURES

Univariable and multivariable analyses were used to assess the prognostic value of predefined clinicopathologic baseline factors on survival.

RESULTS

In a discovery cohort of 357 patients (mean [SD] age, 62.6 [14.2] years; 254 [71.1%] men) with metastatic cutaneous melanoma treated with ICIs, the M category in the AJCC eighth edition showed limited prognostic stratification by both univariable and multivariable analyses. The presence of liver metastases and elevated levels of serum lactate dehydrogenase (LDH) offered superior prognostic separation compared with the M category (liver metastases: hazard ratio, 2.22; 95% CI, 1.48-3.33; P < .001; elevated serum LDH: hazard ratio, 1.73; 95% CI, 1.16-2.58; P = .007). An updated staging system based on these factors was externally validated in a cohort of 652 patients (mean [SD] age, 67.9 [11.6] years; 630 [96.6%] men), with patients without liver metastases or elevated LDH levels having the longest survival (median overall survival, 30.7 months).

CONCLUSIONS AND RELEVANCE

This study found that the AJCC eighth edition M category was poorly reflective of prognosis in patients receiving ICIs. Future staging systems could consider emphasizing the presence of liver metastases and elevated LDH levels. Additional studies are needed to confirm the importance of these and other prognostic biomarkers.

Dermoscopic evaluation of superficial spreading melanoma

Background

Dermoscopy increases the sensitivity of the diagnosis of melanoma, leading to its early identification and increasing the chances of cure.

Objective

To describe the clinical and dermoscopic characteristics of superficial spreading melanomas, and to detect the differences between in situ and invasive 1-mm thick melanomas.

Methods

This was a cross-sectional study in which dermoscopic images of 58 melanomas, grouped according to their thickness, were evaluated.

Results

24 in situ melanomas were evaluated, 28 invasive melanomas with Breslow ≤ 1 mm (0.50 ± 0.22 mm) and six with Breslow > 1 mm (2.35 ± 2.02 mm). In situ melanomas were smaller than invasive melanomas. The most commonly found dermoscopic criteria were asymmetry (84.5%), three or more colors (81.0%), and atypical network (79.3%). A non-specific pattern was more common in in situ melanomas (p = 0.028) and atypical network in invasive melanomas with Breslow 1 mm presented inverted network (p = 0.018).

Study limitations

The sample was selected by convenience, since it was necessary to have a preoperative photo of the tumor, which may have led to the loss of clinically less significant lesions, as well as those highly suggestive of melanoma.

Conclusions

Melanomas in early stages showed a more frequent nonspecific pattern and atypical network, while invasive melanomas showed a multicomponent pattern, three or more colors, and an inverted network.

Metastatic Melanoma Presenting as a Gastric Mass

Melanoma is the most deadly form of skin cancer. While the jejunum, ileum, colon, and rectum are common gastrointestinal sites of metastasis, metastatic melanoma to the stomach is rare and usually not discovered until late in the disease. We report a patient who presented with weight loss and hematemesis; on esophagogastroduodenoscopy, a gastric mass was found, and pathology was consistent with melanoma. 

Regulatory T Cells Play an Important Role in the Prevention of Murine Melanocytic Nevi and Melanomas

Melanocytic nevi are benign proliferations of pigment cells that can occasionally develop into melanomas. There is a significant correlation between increased nevus numbers and melanoma development. Our previous reports revealed that 7,12-dimethylbenz(a)anthracene (DMBA) and 12-O-tetradecanoyl-phorbol-13-acetate (TPA) induced dysplastic nevi in C3H/HeN mice, with a potential to transform into melanomas. To understand the immune mechanisms behind this transformation, we applied increasing DMBA doses followed by TPA to the skin of C3H/HeN mice. We observed that increased doses of DMBA correlated well with increased numbers of nevi. The increased DMBA dose induced diminished immune responses and promoted the expansion of regulatory T cells (Treg) that resulted in increased IL10 and reduced IFNγ levels. Mice with increased nevus numbers had loss of p16 expression. These mice had increased migration of melanocytic cells to lymph nodes (LN) and a greater percent of LNs produced immortalized melanocytic cell lines. DMBA-induced immunosuppression was lost in CD4-knockout (KO) mice. Lymphocytes in the CD4KO mice produced less IL10 than CD8KO mice. Furthermore, CD4KO mice had significantly reduced nevus numbers and size compared with wild-type and CD8KO mice. These results suggest that Tregs play a vital role in the incidence of nevi and their progression to melanoma.Prevention Relevance: There has been little progress in developing novel strategies for preventing premalignant dysplastic nevi from becoming melanomas. In this study in mice, regulatory-T cells enhanced progression of benign nevi to malignant melanomas; and by inhibiting their activity, melanomas could be retarded. The findings identify new possibilities for melanoma prevention in high risk individuals.

Is it Necessary to Perform Sentinel Lymph Node Biopsy in Thin Melanoma? A Retrospective Single Center Analysis

Sentinel lymph node biopsy (SLNB) is a standard procedure for regional lymph node staging and still has the most important prognostic value for the outcome of patients with thin melanoma. In addition to ulceration, SLNB had to be considered even for a single mitotic figure in thin (<1 mm) melanoma according to AJCC7th guideline, therefore, a retrospective review was conducted involving 403 pT1 melanoma patients. Among them, 152 patients suffered from pT1b ulcerated or mitotic rate ≥ 1/ mm2 melanomas according to the AJCC7th staging system. SLNB was performed in 78 cases, of which nine (11.5%) showed SLN positivity. From them, interestingly, we found a relatively high positive sentinel rate (6/78-8%) in the case of thin primary melanomas ˂0.8 mm. Moreover, the presence of regression increased the probability of sentinel positivity by 5.796 fold. After reassessing pT stage based on the new AJCC8th, 37 pT1b cases were reordered into pT1a category. There was no significant relation between other characteristics examined (age, gender, Breslow, Clark level, and mitosis index) and sentinel node positivity. Based on our data, we suggest that mitotic rate alone is not a sufficiently powerful predictor of SLN status in thin melanomas. If strict histopathological definition criteria are applied, regression might be an additional adverse feature that aids in identifying T1 patients most likely to be SLN-positive. After reassessing of pT1b cases according to AJCC8th regression proved to be independent prognostic factor on sentinel lymph node positivity. Our results propose that sentinel lymph node biopsy might also be considered at patients with regressive thin (˂0.8 mm) melanomas.

Optimal treatment strategy for metastatic melanoma patients harboring BRAF-V600 mutations

BRAF-V600 mutations occur in approximately 50% of patients with metastatic melanoma. Immune-checkpoint inhibitors and targeted therapies are both active as first-line treatments in these patients regardless of their mechanisms of action and toxicities. However, an upfront therapeutic strategy is still controversial. In fact, waiting for results of ongoing clinical trials and for new biomarkers, clinicians should base their decision on the clinical characteristics of the patient and on the biological aspects of the tumor. This review provides an overview on BRAF-V600 mutations in melanoma and will discuss their prognostic and clinical significance. Moreover, it will suggest a therapeutic algorithm that can drive therapeutic choice in a first-line setting for BRAF-V600 mutant melanoma patients.

Phenolic Extraction of Moringa Oleifera Leaves Induces Caspase-Dependent and Caspase-Independent Apoptosis through the Generation of Reactive Oxygen Species and the Activation of Intrinsic Mitochondrial Pathway in Human Melanoma Cells

Moringa oleifera Lam. has long been used to treat many diseases, including diabetes, aging, inflammatory, and cancer. Many studies have revealed that the crude extract of Moringa oleifera Lam. leaves possesses anticancer property. Therefore, in this study, the extract of Moringa oleifera leaves was fractionated using different solvents to figure out the most effective fraction for anti-proliferative effect on melanoma cells. Methanol extract (MO-ME), hexane fraction (MO-HE), chloroform fraction (MO-CH), ethyl acetate fraction (MO-EA), and water-soluble fraction (MO-WA) of Moringa oleifera leaves were prepared. Total phenolic and flavonoid contents were determined. The anti-proliferative activity on melanoma cells and normal cells was investigated using WST-1 assay. The apoptotic activity was assessed by testing DNA condensation, DNA fragmentation, and phosphatidylserine (PS) externalization. The expression of apoptosis-related genes, the mitochondrial depolarization, and reactive oxygen species (ROS) were then examined to clarify the underlying molecular mechanisms. In this regard, MO-ME, MO-EA, and MO-CH inhibited the proliferation of both A375 human melanoma cells and A2058 human melanoma cells, but had little effect on WS1 normal human skin fibroblasts and primary normal human dermal fibroblasts (NHDF). Among fractions, the phenolic-rich MO-EA markedly inhibited the growth of A375 cells in a dose- and time-dependent manner. The anti-proliferation was supposed to be mediated via apoptosis, which was demonstrated by the significant increase of condensed chromatin, DNA fragmentation, and PS externalization. The apoptosis was stimulated by enhanced ROS production and reduction of mitochondrial membrane potential. MO-EA activated Bax while reducing Bcl-2 expression, leading to an increase in Bax/Bcl-2 ratio. The mechanisms of cell death involved in activation of Caspase-3/7 and Caspase-9 (Caspase-dependent pathway), activation, and translocation of apoptosis-inducing factor (AIF) into the nucleus (Caspase-independent pathway). Our study indicated that the phenolic-rich fraction exerted significant anticancer effects on melanoma cells in vitro which involved in Caspase-dependent and Caspase-independent apoptosis pathways mediated by mitochondrial ROS. These results provided a fundament for the using of phenolic-rich fraction of Moringa oleifera leaves to treat skin cancer effectively.

A pilot clinical trial testing topical resiquimod and a xenopeptide as immune adjuvants for a melanoma vaccine targeting MART-1

A vaccine that could expand melanoma-specific T cells might reduce the risk of recurrence of resected melanoma and could provide an alternative or adjunct to standard immunotherapy options. We tested the safety and immunogenicity of a vaccine coupling a melanoma-associated peptide with a xenogenic peptide (to promote epitope spreading) and/or resiquimod (to activate antigen-presenting cells). HLA-A2-positive patients with resected stage II, III, and IV melanoma were assigned to treatment on one of three schedules. All patients received three subcutaneous doses of the peptide MART-1a mixed with Montanide. In addition, patients on schedule 1 received the xenoantigen peptide Gag267-274, patients on schedule 2 received topical resiquimod, and patients on schedule 3 received both Gag267-274 and resiquimod. Blood samples were tested for the frequency of antigen-specific T cells by tetramer assay, as well as immune cell subtypes and plasma cytokine levels. Patients enrolled from October 2012 to December 2014, with 10 patients enrolling to each schedule. The most common adverse events were injection site reaction (26 patients) and fatigue (15 patients). Tetramer analysis revealed antigen-specific responses (defined as doubling of MART-1a-specific T cells from pretreatment to post-treatment) in 20, 60, and 40% of patients treated on schedules 1, 2, and 3, respectively. Vaccine treatment consisting of MART-1a peptide, Gag267-274, Montanide, and topical resiquimod was well-tolerated. The addition of the Gag267-274 xenoantigen was not associated with an increase in the response to MART-1a, whereas use of topical resiquimod was associated with a higher frequency of MART-1a-specific T-cell responses that did not meet statistical significance.

Mitochondria-mediated Caspase-dependent and Caspase-independent apoptosis induced by aqueous extract from Moringa oleifera leaves in human melanoma cells

Malignant melanoma is a very aggressive and serious type of cutaneous cancer. Previous studies indicated the anti-cancer activity of aqueous extract of Moringa oleifera Lam. leaves (MOE) against a variety of cell lines. However, there has not been much research about the effect of MOE on melanoma. Therefore, this study was about to investigate the anti-proliferation mediated by apoptosis of MOE on human melanoma cell lines. Furthermore, the related molecular mechanisms of the apoptosis were also examined. An aqueous extract of Moringa oleifera leaves was prepared and the anti-proliferative activity on melanoma cells and normal cells was tested using WST-1 assay. The apoptotic hallmarks including DNA condensation and phosphatidylserine (PS) externalization were assessed. The expression of apoptosis-related genes and the depolarization of mitochondrial membrane potential were then examined to clarify the underlying molecular mechanisms. MOE inhibited cell growth of A375 cells and A2058 cells in a dose-dependent manner but had little effect on human normal fibroblasts. The cell growth inhibition was induced by apoptosis which was expressed via chromatin condensation and PS externalization. MOE decreased mitochondrial membrane potential. Additionally, MOE increased Bax/Bcl-2 ratio, activated Caspase-3/7, Caspase-9, PARP and AIF translocation, leading to apoptotic cell death. Our study indicated that MOE exerted significant anti-cancer effects on melanoma cells in vitro which involved mitochondria-mediated Caspase-dependent and Caspase-independent apoptosis pathways. These results provided a scientific approach for using Moringa oleifera leaves as an alternative therapy to treat skin cancer.

Impact of Immediate Surgical Reconstruction Following Wide Local Excision of Malignant Head and Neck Melanoma

Background

The role of surgical reconstruction following melanoma extirpation is well recognized. Although technical considerations depend on patient anatomy and surgeon preference, the optimal timing of reconstruction remains unclear. This study aims to evaluate clinical and oncologic outcomes in melanoma extirpation followed by immediate reconstruction.

Methods

We retrospectively identified patients who underwent immediate reconstruction following head and neck melanoma excision at our institution between January 2013 and December 2016. Demographic and clinical characteristics, operative variables, and outcome data were extracted.

Results

Overall, 197 patients (male 70.6%) underwent excision followed by immediate reconstruction. Of the 70 patients with a history of cutaneous malignancy, 46 (65.7%) had a prior melanoma and 26 (37.1%) had 2 or more types of skin cancers. Of the 202 lesions resected, 138 (68.3%) were invasive, whereas 64 (31.7%) were in situ. The most frequent anatomic location involved was the cheek (34.2%), followed by scalp (31.2%). Reconstruction technique varied, with 116 (57.4%) lesions repaired by adjacent tissue transfer, 24 (11.9%) by full-thickness skin graft, 23 (11.4%) by complex primary closure, 17 (8.4%) by split-thickness skin graft, and 22 (10.9%) by more than 1 technique. On postoperative pathologic assessment, 2 patients had positive margins and 5 experienced local recurrence (mean follow-up: 2.3 years). In an unadjusted bivariate analysis, history of melanoma (P = 0.015) was significantly associated with local recurrence.

Conclusions

Reconstruction at time of excision is an oncologically safe approach for the management of patients with malignant melanoma. A prior history of melanoma may be associated with local recurrence.

Bioinspired nanoplatelets for chemo-photothermal therapy of breast cancer metastasis inhibition

Breast cancer is associated with high mortality due to tumor metastasis. The anti-metastasis efficacy of photochemotherapy is strictly limited by poor targeting capability with respect to circulating tumor cells (CTCs) in blood and lymph. Herein, we decorate the platelet membrane (PM) on a surface of nanoparticles (NPs), referred to as nanoplatelets. A chemotherapeutic drug, doxorubicin (DOX), and an FDA-approved photothermal agent, indocyanine green (ICG), are co-encapsulated into the biomimetic nanoplatelets. Nanoplatelets possess immune surveillance-escaping capability and specifically capture and clear CTCs in both blood and lymphatic circulations via high-affinity interactions between the P-Selectin of PM and CD44 receptors of tumor cells. PM-coated NPs show greater cellular uptake in MDA-MB-231 breast cancer cells and further elicit higher cytotoxicity to tumor cells relative to uncoated NPs. In vivo, we disclose that the multifunctional nanoplatelets not only completely ablate the primary tumor but also inhibit breast cancer metastasis with high efficiency in the three established xenograft or orthotopic breast tumor-bearing mice models. We conclude that such biomimetic nanoplatelets represent a promising strategy of coating a surface of nanoparticles with platelet membrane to actively capture and destroy CTCs in blood and lymph in breast cancer anti-metastasis therapy.

Proteomics-based insights into mitogen-activated protein kinase inhibitor resistance of cerebral melanoma metastases

Background

MAP kinase inhibitor (MAPKi) therapy for BRAF mutated melanoma is characterized by high response rates but development of drug resistance within a median progression-free survival (PFS) of 9-12 months. Understanding mechanisms of resistance and identifying effective therapeutic alternatives is one of the most important scientific challenges in melanoma. Using proteomics, we want to specifically gain insight into the pathophysiological process of cerebral metastases.

Methods

Cerebral metastases from melanoma patients were initially analyzed by a LC-MS shotgun approach performed on a QExactive HF hybrid quadrupole-orbitrap mass spectrometer. For further validation steps after bioinformatics analysis, a targeted LC-QQQ-MS approach, as well as Western blot, immunohistochemistry and immunocytochemistry was performed.

Results

In this pilot study, we were able to identify 5977 proteins by LC-MS analysis (data are available via ProteomeXchange with identifier PXD007592). Based on PFS, samples were classified into good responders (PFS ≥ 6 months) and poor responders (PFS [Formula: see text] 3 months). By evaluating these proteomic profiles according to gene ontology (GO) terms, KEGG pathways and gene set enrichment analysis (GSEA), we could characterize differences between the two distinct groups. We detected an EMT feature (up-regulation of N-cadherin) as classifier between the two groups, V-type proton ATPases, cell adhesion proteins and several transporter and exchanger proteins to be significantly up-regulated in poor responding patients, whereas good responders showed an immune activation, among other features. We identified class-discriminating proteins based on nearest shrunken centroids, validated and quantified this signature by a targeted approach and could correlate parts of this signature with resistance using the CPL/MUW proteome database and survival of patients by TCGA analysis. We further validated an EMT-like signature as a major discriminator between good and poor responders on primary melanoma cells derived from cerebral metastases. Higher immune activity is demonstrated in patients with good response to MAPKi by immunohistochemical staining of biopsy samples of cerebral melanoma metastases.

Conclusions

Employing proteomic analysis, we confirmed known extra-cerebral resistance mechanisms in the cerebral metastases and further discovered possible brain specific mechanisms of drug efflux, which might serve as treatment targets or as predictive markers for these kinds of metastasis.

Malignant Melanoma of the Breast: A Case Report and Review of the Literature

Primary breast melanoma is a rare entity that on routine histology may be mistaken for triple-negative breast cancer. A high degree of clinical suspicion is necessary to make this diagnosis. This case report describes the presentation and treatment of primary breast melanoma.

[The Diagnosis of Metastatic Malignant Melanoma Incidentally Found during a National Health Screening Endoscopy: A Case Report]

Malignant melanoma is one of the most common malignant diseases of the gastrointestinal tract. It has been reported that the malignant melanoma metastasizes not only to the small intestine due to the abundant blood supply, but also to the stomach, colon, and esophagus. Gastrointestinal metastasis is usually suspected depending on the clinical symptoms, as well as based on radiological or endoscopic findings. Imunohistochemical stains, such as Melan-A/Melanoma antigen recognized by T cell-1 or human melanoma black-45, are useful for confirming the diagnosis of malignant melanoma. A 44-year-old male received an operation due to a malignant melanoma at the left thumb two years ago. On the national health screening endoscopy, a submucosal tumor with hyperemic change on the top was found. The final diagnosis was a metastatic malignant melanoma in the stomach, pancreas, and pelvic bone. We recommend that endoscopists should consider the potential malignancy of subepithelial tumor with mucosa change, despite the tumor size being less than 1 cm.

Clinical and prognostic factors in 98 patients with malignant melanoma in China

Objective To investigate clinical and prognostic factors in patients with malignant melanoma (MM) in China. Methods A total of 98 MM patients were enrolled in the study. Enumeration data were analyzed using Fisher's exact probability tests or χ2 tests. Survival rates were calculated using log-rank tests. A Cox multivariate regression analysis was performed to determine independent prognostic factors. Results The male: female incidence ratio was 1.88:1. The highest incidence rate was seen in the 45-65 year age group. Primary lesion ulceration was seen in 60.2% of patients. The 1-year, 3-year and 5-year survival rates were 85.7%, 34.7% and 13.3%, respectively. In univariate analyses, the 5-year survival rate in patients was significantly associated with ulceration (P < 0.01), clinical stage (P < 0.01) and surgical excision of the tumor (P < 0.01). Cox multivariate regression analysis confirmed that ulceration and clinical stage were independent prognostic factors. Conclusions Some clinical characteristics of MM patients in China are significantly different from those of patients in Western countries. Ulceration and clinical stage are independent risk factors for poor survival in MM patients.

Dual addressing of thymidine synthesis pathways for effective targeting of proliferating melanoma

Here, we examined the potential of blocking the thymidine de novo synthesis pathways for sensitizing melanoma cells to the nucleoside salvage pathway targeting endogenous DNA irradiation. Expression of key nucleotide synthesis and proliferation enzymes thymidylate synthase (TS) and thymidine kinase 1 (TK1) was evaluated in differentiated (MITF^high [microphthalmia‐associated transcription factor] IGR1) and invasive (MITF^mediumIGR37) melanoma cells. For inhibition of de novo pathways cells were incubated either with an irreversible TS inhibitor 5‐fluoro‐2′‐deoxyuridine (FdUrd) or with a competitive dihydrofolate‐reductase (DHFR) inhibitor methotrexate (MTX). Salvage pathway was addressed by irradiation‐emitting thymidine analog [^123/125I]‐5‐iodo‐4′‐thio‐2′‐deoxyuridine (^123/125I‐ITdU). The in vivo targeting efficiency was visualized by single‐photon emission computed tomography. Pretreatment with FdUrd strongly increased the cellular uptake and the DNA incorporation of ¹²⁵I‐ITdU into the mitotically active IGR37 cells. This effect was less pronounced in the differentiated IGR1 cells. In vivo, inhibition of TS led to a high and preferential accumulation of ¹²³I‐ITdU in tumor tissue. This preclinical study presents profound rationale for development of therapeutic approach by highly efficient and selective radioactive targeting one of the crucial salvage pathways in melanomas.

Moringa oleifera fruit induce apoptosis via reactive oxygen species-dependent activation of mitogen-activated protein kinases in human melanoma A2058 cells

The present study was performed to determine the effect of Moringa oleifera fruit extract on the apoptosis of human melanoma A2058 cells. A2058 cells were treated for 72 h with Moringa oleifera fruit extract at 50-100 µg/ml, and cell viability with apoptotic changes was examined. The involvement of reactive oxygen species (ROS) and mitogen-activated protein kinases (MAPKs) was examined. It was revealed that Moringa oleifera fruit extract significantly inhibited the cell viability and promoted apoptosis of A2058 cells in a concentration-dependent manner. Moringa oleifera fruit extract-treated A2058 cells exhibited increased activities of cleaved caspase-9 and caspase-3. It also caused an enhancement of MAPK phosphorylation and ROS production. The pro-apoptotic activity of Moringa oleifera fruit extract was significantly reversed by pretreatment with the c-Jun N-terminal kinase (JNK) inhibitor SP600125, extracellular-signal-regulated kinase (ERK) inhibitor PD98058 or ROS inhibitor N-acetyl-L-cysteine. Taken together, Moringa oleifera fruit extract is effective in inducing mitochondrial apoptosis of A2058 cells, which is mediated through induction of ROS formation, and JNK and ERK activation. Moringa oleifera fruit extract may thus have therapeutic benefits for human melanoma A2058 cells.

Poly(lactic acid)-based particulate systems are promising tools for immune modulation

Poly(lactic acid) (PLA) is one of the most successful and versatile polymers explored for controlled delivery of bioactive molecules. Its attractive properties of biodegradability and biocompatibility in vivo have contributed in a meaningful way to the approval of different products by the FDA and EMA for a wide range of biomedical and pharmaceutical applications, in the past two decades. This polymer has been widely used for the preparation of particles as delivery systems of several therapeutic molecules, including vaccines. These PLA vaccine carriers have shown to induce a sustained and targeted release of different bacterial, viral and tumor-associated antigens and adjuvants in vivo, triggering distinct immune responses. The present review intends to highlight and discuss the major advantages of PLA as a promising polymer for the development of potent vaccine delivery systems against pathogens and cancer. It aims to provide a critical discussion based on preclinical data to better understand the major effect of PLA-based carrier properties on their interaction with immune cells and thus their role in the modulation of host immunity.

STATEMENT OF SIGNIFICANCE

During the last decades, vaccination has had a great impact on global health with the control of many severe diseases. Polymeric nanosystems have emerged as promising strategies to stabilize vaccine antigens, promoting their controlled release to phagocytic cells, thus avoiding the need for multiple administrations. One of the most promising polymers are the aliphatic polyesters, which include the poly(lactic acid). This is a highly versatile biodegradable and biocompatible polymer. Products containing this polymer have already been approved for all food and some biomedical applications. Despite all favorable characteristics presented above, PLA has been less intensively discussed than other polymers, such as its copolymer PLGA, including regarding its application in vaccination and particularly in tumor immunotherapy. The present review discusses the major advantages of poly(lactic acid) for the development of potent vaccine delivery systems, providing a critical view on the main properties that determine their effect on the modulation of immune cells.

Melanoma with gastric metastases

An 81-year-old woman with a history of malignant melanoma who presented with dyspnea and fatigue was found to have metastases to the stomach detected on endoscopy. Primary cutaneous malignant melanoma with gastric metastases is a rare occurrence, and it is often not detected until autopsy because of its non-specific manifestations.

A combination of high dose rate (10X FFF/2400 MU/min/10 MV X-rays) and total low dose (0.5 Gy) induces a higher rate of apoptosis in melanoma cells in vitro and superior preservation of normal melanocytes

The aim of this study was to determine the apoptotic effects, toxicity, and radiosensitization of total low dose irradiation delivered at a high dose rate in vitro to melanoma cells, normal human epidermal melanocytes (HEM), or normal human dermal fibroblasts (HDF) and to study the effect of mitochondrial inhibition in combination with radiation to enhance apoptosis in melanoma cells. Cells irradiated using 10X flattening filter-free (FFF) 10 MV X-rays at a dose rate of 400 or 2400 MU/min and a total dose of 0.25–8 Gy were analyzed by cell/colony counting, MitoTracker, MTT, and DNA-damage assays, as well as by quantitative real-time reverse transcriptase PCR in the presence or absence of mitochondrial respiration inhibitors. A dose rate of 2400 MU/min killed on average five-fold more melanoma cells than a dose rate 400 MU/min at a total dose of 0.5 Gy and preserved 80% survival of HEM and 90% survival of HDF. Increased apoptosis at the 2400 MU/min dose rate is mediated by greater DNA damage, reduced cell proliferation, upregulation of apoptotic genes, and downregulation of cell cycle genes. HEM and HDF were relatively unharmed at 2400 MU/min. Radiation induced upregulation of mitochondrial respiration in both normal and cancer cells, and blocking the respiration with inhibitors enhanced apoptosis only in melanoma cells. A high dose rate with a low total dose (2400 MU/min, 0.5 Gy/10X FFF 10 MV X-rays) enhances radiosensitivity of melanoma cells while reducing radiotoxicity toward HEM and HDF. Selective cytotoxicity of melanoma cells is increased by blocking mitochondrial respiration.

Developing strategies to predict photodynamic therapy outcome: the role of melanoma microenvironment

Melanoma is among the most aggressive and treatment-resistant human skin cancer. Photodynamic therapy (PDT), a minimally invasive therapeutic modality, is a promising approach to treating melanoma. It combines a non-toxic photoactivatable drug called photosensitizer with harmless visible light to generate reactive oxygen species which mediate the antitumor effects. The aim of this review was to compile the available data about PDT on melanoma. Our comparative analysis revealed a disconnection between several hypotheses generated by in vitro therapeutic studies and in vivo and clinical assays. This fact led us to highlight new preclinical experimental platforms that mimic the complexity of tumor biology. The tumor and its stromal microenvironment have a dynamic and reciprocal interaction that plays a critical role in tumor resistance, and these interactions can be exploited for novel therapeutic targets. In this sense, we review two strategies used by photodynamic researchers: (a) developing 3D culture systems which mimic tumor architecture and (b) heterotypic cultures that resemble tumor microenvironment to favor therapeutic regimen design. After this comprehensive review of the literature, we suggest that new complementary preclinical models are required to better optimize the clinical outcome of PDT on skin melanoma.

Coffee drinking and cutaneous melanoma risk in the NIH-AARP diet and health study

BACKGROUND

Cutaneous melanoma is the fifth most common cancer in the United States. Modifiable risk factors, with the exception of exposure to ultraviolet radiation (UVR), are poorly understood. Coffee contains numerous bioactive compounds and may be associated inversely with melanoma. However, previous epidemiological evidence is limited.

METHODS

Coffee intake was assessed at baseline with a food frequency questionnaire in the National Institutes of Health-AARP prospective cohort study. Among 447 357 non-Hispanic whites who were cancer-free at baseline, 2904 incident cases of malignant melanoma were identified during 4 329 044 person-years of follow-up, with a median of 10.5 years of follow-up. Multivariable-adjusted Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for coffee intake and subsequent melanoma risk with non-coffee drinkers as the reference group. Statistical tests were two-sided, and P values less than .05 were interpreted as statistically significant.

RESULTS

The highest category of coffee intake was inversely associated with malignant melanoma (≥4 cups/day: HR = 0.80, 95% CI = 0.68 to 0.93, P trend = .01). This association was statistically significant for caffeinated (≥4 cups/day: HR = 0.75, 95% CI = 0.64 to 0.89, P trend = .01) but not for decaffeinated coffee (P trend = .55).

CONCLUSIONS

Higher coffee intake was associated with a modest decrease in risk of melanoma in this large US cohort study. Additional investigations of coffee intake and its constituents, particularly caffeine, with melanoma are warranted.

Gastric metastasis from sphenoid sinus melanoma: A case report

Clinical reports of primary sphenoid sinus melanoma and isolated gastric metastatic melanoma are rare. Thus, to the best of our knowledge, the present study reports the first case of isolated gastric metastasis from a sphenoid sinus melanoma. The aim of the present study was to discuss the clinicopathological and radiographic characteristics, the treatment strategy and the prognosis of sphenoid sinus metastatic malignant melanoma of the stomach. Although almost 60% of patients who succumb to melanoma exhibit gastrointestinal metastases at autopsy, antemortem diagnosis is uncommon; this is predominantly due to gastric metastatic melanoma presenting with non-specific symptoms similar to other common gastrointestinal diseases. Gastrectomy may prolong overall survival and improve the quality of life for gastric metastatic melanoma patients, and the present case emphasizes the importance of palliative surgery in such cases.

Rare presentations of primary melanoma and special populations: a systematic review

A subset of patients with melanoma present in rare and unique clinical circumstances requiring specific considerations with respect to diagnostic and therapeutic interventions. Herein, we present our review of patients with: (1) primary mucosal melanoma of the head and neck, gastrointestinal, and genitourinary tracts; (2) primary melanoma of the eye; (3) desmoplastic melanoma; (4) subungual melanoma; (5) melanoma in special populations: children, nonwhites, as well as a discussion of familial melanoma.

The immunomodulatory effects of bevacizumab on systemic immunity in patients with metastatic melanoma

Metastatic melanoma is near-to-invariably a fatal disease. As novel therapeutic strategies against metastatic melanoma are urgently needed, we have tested a combinatorial regimen consisting of conventional chemotherapy coupled to bevacizumab, a monoclonal antibody that inhibit angiogenesis, demonstrating some clinical benefit. A preliminary assessment of one of our clinical trials points to a previously unrecognized immunomodulatory effect of bevacizumab. Herein, we evaluate the immunomodulatory effect of bevacizumab when administered together with conventional chemotherapy to patients with metastatic melanoma. To this aim, we measured the abundance of various lymphocyte subsets among peripheral blood mononuclear cells (PBMCs) as well as the circulating levels of 42 cytokines, chemokines and growth factors in patients with metastatic melanoma who received albumin-bound paclitaxel plus carboplatin, either as a standalone intervention (AC, 55 subjects) or combined with bevacizumab (ACB, 39 individuals), in the context of clinical trials N057e and N0775, respectively. Relative shifts in PBMC subsets and cytokine levels were calculated (relative to baseline levels) when patients underwent restaging evaluation after two cycles of therapy. The Mann-Whitney U test was used to compare responses between the groups. Bevacizumab failed to affect the T_H1/T_H2 cell ratio in this patient cohort. However, we observed a significant increase in CD8⁺ lymphocytes in patients who received ACB (+38%) but not in subjects treated with AC only (-10%) (p = 0.03). Moreover, circulating interleuikin-6 (IL-6) levels were reduced in patients treated with ACB (-42%) but not in individuals receiving AC only (28%) (p = 0.0018). Thus, the addition of bevacizumab to chemotherapy for the treatment of metastatic melanoma exerts immunomodulatory effects.

Wrong melanoma thickness measurement: check it or leave it?

Cutaneous malignant melanoma (CMM) is one of the most aggressive forms of skin cancer, accounting for about 90% of deaths from cutaneous neoplasms, and its incidence has increased significantly in recent years. According to the 2012 European criteria for diagnosis and treatment of malignant melanoma, diagnosis should be based on the combination of clinical features, dermoscopic data and histological examination, preferably after excisional biopsy. Tumour thickness and other parameters for local staging according to the AJCC classification should be included in the pathology report. Although many factors influence the prognosis and course of the disease, it has been established in a number of studies that tumour thickness is the most important parameter. Therapy of malignant melanoma in its initial stages mostly consists of wide local excision with 1 to 2 cm margins, and sentinel lymph node biopsy that is usually performed in cases of tumours with a thickness greater than 1 mm. We present the case of a 58-year-old Bulgarian male with cutaneous superficial spreading malignant melanoma, in which, after complete excision, histological examination established an inaccurate tumour thickness (0.7 mm), with consequent inadequate staging and further management. After reassessment of the results in another institution (as well as their confirmation by two additional independent histopathology laboratories in our country – 1.92 mm), in the National Oncological Hospital where the patient was initially evaluated, sentinel lymph node biopsy was not performed, contrary to the generally accepted European and World standards. With the present case we raise some current issues regarding diagnosis and therapy of Bulgarian patients (not only in the case presented) with malignant melanoma in the 21st century, and discuss the urgent need for external quality control procedures and standardization of the histopathologic reporting, which is of paramount importance in the staging and subsequent management of these patients.

New malignancies after squamous cell carcinoma and melanomas: a population-based study from Norway

Background

Skin cancer survivors experience an increased risk for subsequent malignancies but the associated risk factors are poorly understood. This study examined the risk of a new primary cancer following an initial skin cancer and assessed risk factors associated with second primary cancers.

Methods

All invasive cutaneous malignant melanomas (CMM, N = 28 069) and squamous cell carcinomas (SCC, N = 24 620) diagnosed in Norway during 1955–2008 were included. Rates of new primary cancers in skin cancer survivors were compared to rates of primary malignancies in the general population using standardized incidence ratios (SIR). Discrete-time logistic regression models were applied to individual-level data to estimate cancer risk among those with and without a prior skin cancer, accounting for residential region, education, income, parenthood, marital status and parental cancer status, using a 20% random sample of the entire Norwegian population as reference. Further analyses of the skin cancer cohort were undertaken to determine risk factors related to subsequent cancers.

Results

During follow-up, 9608 new primary cancers occurred after an initial skin cancer. SIR analyses showed 50% and 90% increased risks for any cancer after CMM and SCC, respectively (p < 0.01). The logistic regression model suggested even stronger increase after SCC (130%). The highest risk was seen for subsequent skin cancers, but several non-skin cancers were also diagnosed in excess: oral, lung, colon, breast, prostate, thyroid, leukemia, lymphoma and central nervous system. Factors that were associated with increased risk of subsequent cancers include male sex, older age, lower residential latitude, being married and low education and income. Parental cancer did not increase the risk of a subsequent cancer after SCC, but was a significant predictor among younger CMM survivors.

Conclusions

Our results provide information on shared environmental and genetic risk factors for first and later cancers and may help to identify individuals at high risk for subsequent cancers, which will be important as skin cancer incidence continues to rise.

Radiopharmaceutical therapy of patients with metastasized melanoma with the melanin-binding benzamide 131I-BA52

The performance of cytotoxic drugs is defined by their selectivity of uptake and action in tumor tissue. Recent clinical responses achieved by treating metastatic malignant melanoma with therapeutic modalities based on gene expression profiling showed that malignant melanoma is amenable to systemic treatment. However, these responses are not persistent, and complementary targeted treatment strategies are required for malignant melanoma.

METHODS

Here we provide our experience with different labeling procedures for the radioiodination of benzamides and report on initial dosimetry data and the first therapeutic application of (131)I-BA52, a novel melanin-binding benzamide in patients with metastatic malignant melanoma. Twenty-six adults with histologically documented metastasized malignant melanoma received a single dose of 235 ± 62 MBq of (123)I-BA52 for planar and SPECT/CT imaging. Nine patients were selected for radionuclide therapy and received a median of 4 GBq (minimum, 0.51 GBq; maximum, 6.60 GBq) of the β-emitting radiopharmaceutical (131)I-BA52.

RESULTS

A trimethyltin precursor-based synthesis demonstrated high radiochemical yields in the large-scale production of radioiodinated benzamides required for clinical application. (123)I-BA52 showed specific uptake and long-term retention in tumor tissue with low transient uptake in the excretory organs. In tumor tissue, a maximum dose of 12.2 Gy per GBq of (131)I-BA52 was calculated. The highest estimated dose to a normal organ was found for the lung (mean, 3.1 Gy/GBq). No relevant acute or mid-term toxicity was observed with the doses administered until now. Even though dosimetric calculations reveal that the doses applied in this early phase of clinical application can be significantly increased, we observed antitumor effects with follow-up imaging, and single patients of the benzamide-positive cohort of patients (3/5 of the patients receiving a dose > 4.3 GBq) demonstrated a surprisingly long survival of more than 2 y.

CONCLUSION

These data indicate that systemic radionuclide therapy using (131)I-BA52 as a novel approach for the therapy of malignant melanoma is of considerable potential. Future trials should be done to enhance the precision of dosimetry, validate the maximum tolerable dose, and evaluate the effectiveness of the treatment in a prospective manner.

Metastatic melanoma to the upper aerodigestive tract: a systematic review of the literature

This study is a systematic review of the literature that was performed to clarify the natural history and treatment outcomes of upper aerodigestive tract metastases from cutaneous melanoma. A search of the MEDLINE database was undertaken from 1950 to 2013 to identify relevant manuscripts for this review. Article inclusion required cases with documentation of previous cutaneous melanoma primary lesions, adequate survival data, and description of metastatic treatment. Individual patient data were extracted from source articles for analysis of survival outcomes. A systematic search revealed 34 relevant articles with 37 cases for inclusion. Metastases were identified throughout the upper aerodigestive tract with a predilection for the oropharynx, larynx, and oral cavity. Treatment outcomes were estimated with the Kaplan-Meier method, with survival of 37% and 16% at 1 and 5 years, respectively. As expected from previous reports, 73% presented with disseminated disease burden with almost universally poor prognosis despite locoregional or systemic therapy. Conversely, a group of patients with limited metastatic burden had improved treatment response with a 1-year survival of 90%, denoting a hazard ratio of 9.7332 (95% confidence interval, 4.5-21.1) for disseminated disease in comparison. Upper aerodigestive tract metastases of melanoma thus are rare clinical entities that in general present in the setting of disseminated disease and evidently necessitate a focus on palliation. In contrast, for those with a limited metastatic burden, aggressive multimodality therapy including complete metastectomy can produce a significant survival advantage.

The influence of dermatologist and primary care physician visits on melanoma outcomes among Medicare beneficiaries

BACKGROUND

Ambulatory visits to dermatologists and primary care physicians (PCPs) may improve melanoma outcomes through early detection. We sought to measure the effect of dermatologist and PCP visits on melanoma stage at diagnosis and mortality.

METHODS

We used data from the database linking Surveillance Epidemiology and End Results (SEER) and Medicare data (1994 to 2005) to examine patterns of dermatologist and PCP ambulatory visits before diagnosis for 18,884 Medicare beneficiaries with invasive melanoma or unknown stage at diagnosis. Visits were assessed during the 2-year time interval before the month of diagnosis. We examined whether dermatologist and PCP visits were associated with diagnosis of thinner melanomas (defined as local stage tumors having Breslow thickness <1 mm) and lower melanoma mortality.

RESULTS

Medicare beneficiaries visiting both a dermatologist and PCP before diagnosis had greater odds of diagnosis of a thin melanoma (adjusted odds ratio, 1.26; 95% confidence interval, 1.12-1.41) and lower melanoma mortality (adjusted hazard ratio 0.66, 95% confidence interval, 0.57-0.76) compared with those without such visits. The mortality findings were attenuated once stage at diagnosis was adjusted for in the multivariable model.

CONCLUSION

Improved melanoma outcomes among Medicare beneficiaries may depend on adequate access and use of dermatologist and PCP services.

Melanoma of stomach

INTRODUCTION

Melanoma of gastrointestinal tract can be either primary or secondary to metastases from other sites like skin, mucous membranes, and uvea. Primary gastrointestinal melanoma is rare and still rarer is stomach involvement.

CASE REPORT

We report a case of primary malignant melanoma of stomach in a 50-year-old female who presented with an axillary lymphadenopathy.

CONCLUSION

Melanoma of stomach is rare. It has characteristic endoscopic appearance. Differentiation of primary from secondary melanoma is possible on clinical behavior and histological characteristics.

Serum peptidomic biomarkers for pulmonary metastatic melanoma identified by means of a nanopore-based assay

The significant mortality rate associated with metastatic melanoma, which exceeds the number of deaths attributed to the primary tumor, is primarily due to poor diagnosis and increased resistance to systemic therapy. Early detection and treatment of invasive melanoma are therefore crucial to increase survival rates. Low molecular weight proteins and peptides have garnered significant interest as biomarker candidates as they potentially represent a snap shot of pathological condition within the body and, by extension, the organism as a whole. We have developed a nanoporous silica-based platform to segregate the low molecular weight from the high molecular weight protein fraction to aid in the detection of peptides from serum samples using mass spectrometry. The combination of sample treatment with our platform, MALDI-TOF MS and following biostatistical analysis led to the discovery and identification of 27 peptides that are potential biomarkers associated with the development of pulmonary metastatic melanoma. We strongly believe our findings can assist to discover stage-specific peptide signatures and lead to more specific and personalized treatments for patients suffering from pulmonary metastatic melanoma.

Tumor location and nature of lymphatic vessels are key determinants of cancer metastasis

Tumor metastasis to lymph nodes is a key indicator of patient survival, and is enhanced by the neo-lymphatics induced by tumor-secreted VEGF-C or VEGF-D, acting via VEGFR-3 signalling. These targets constitute important avenues for anti-metastatic treatment. Despite this new understanding, clinical observations linking metastasis with tumor depth or location suggest that lymphangiogenic growth factors are not the sole determinants of metastasis. Here we explored the influence of tumor proximity to lymphatics capable of responding to growth factors on nodal metastasis in a murine VEGF-D over-expression tumor model. We found that primary tumor location profoundly influenced VEGF-D-mediated lymph node metastasis: 89 % of tumors associated with the flank skin metastasised, in contrast with only 19 % of tumors located more deeply on the body wall (p < 0.01). Lymphatics in metastatic tumors arose from small lymphatics, and displayed distinct molecular and morphological profiles compared with those found in normal lymphatics. Smaller lymphatic subtypes were more abundant in skin (2.5-fold, p < 0.01) than in body wall, providing a richer source of lymphatics for VEGF-D(+) skin tumors, a phenomenon also confirmed in human samples. This study shows that the proximity of a VEGF-D(+) primary tumor to small lymphatics is an important determinant of metastasis. These observations may explain why tumor location relative to the lymphatic network is prognostically important for some human cancers.

RSK promotes G2 DNA damage checkpoint silencing and participates in melanoma chemoresistance

The incidence of malignant melanoma is growing rapidly worldwide and there is still no effective therapy for metastatic disease. This type of cancer is highly resistant to conventional DNA-damaging chemotherapeutics, and intense research has been dedicated for understanding the molecular pathways underlying chemoresistance. The Ras/mitogen-activated protein kinase (MAPK) signalling pathway is often deregulated in melanoma, which frequently harbours activating mutations in NRAS or BRAF. Herein, we demonstrate that the MAPK-activated protein kinase RSK (p90 ribosomal S6 kinase) contributes to melanoma chemoresistance by altering their response to chemotherapeutic agents. We find that RSK phosphorylates checkpoint kinase 1 (Chk1) at an inhibitory site, Ser280, both in vitro and in vivo. Our results indicate that RSK is the predominant protein kinase operating downstream of mitogens and oncogenes of the Ras/MAPK pathway, and consistent with this, we find that RSK constitutively phosphorylates Chk1 in melanoma. We show that RSK inhibition increases Chk1 activity in response to DNA-damaging agents, suggesting that the Ras/MAPK pathway modulates Chk1 function and the response to DNA damage. Accordingly, we demonstrate that RSK promotes G2 DNA damage checkpoint silencing in a Chk1-dependent manner, and find that RSK inhibitors sensitize melanoma cells to DNA-damaging agents. Together, our results identify a novel link between the Ras/MAPK pathway and the DNA damage response, and suggest that RSK inhibitors may be used to modulate chemosensitivity, which is one of the major obstacles to melanoma treatment.

Inhibition of tissue factor by ixolaris reduces primary tumor growth and experimental metastasis in a murine model of melanoma

Melanoma is a highly metastatic cancer and there is strong evidence that the clotting initiator protein, tissue factor (TF), contributes to its aggressive pattern. TF inhibitors may attenuate primary tumor growth and metastasis. In this study, we evaluated the effect of ixolaris, a TF inhibitor, on a murine model of melanoma B16F10 cells. Enzymatic assays performed with B16F10 and human U87-MG tumor cells as the TF source showed that ixolaris inhibits the generation of FX in either murine, human or hybrid FVIIa/TF complexes. The effect of ixolaris on the metastatic potential was further estimated by intravenous injection of B16F10 cells in C57BL/6 mice. Ixolaris (250 μg/kg) dramatically decreased the number of pulmonary tumor nodules (4 ± 1 compared to 47 ± 10 in the control group). Furthermore, a significant decrease in tumor weights was observed in primary tumor growth assays in animals treated with ixolaris (250 μg/kg) from days 3 to 18 after a subcutaneous inoculation of melanoma cells. Remarkably, immunohistochemical analyses showed that inhibition of melanoma growth by ixolaris is accompanied by a significant downregulation of both vascular endothelial growth factor (VEGF) expression and microvascular density in the tumor mass. Our data demonstrate that ixolaris targets B16F10 cell-derived TF, resulting in the reduction of both the primary tumor growth and the metastatic potential of melanoma, as well as the inhibition of tumor angiogenesis. Therefore TF may be a potential target for the treatment of this aggressive malignancy.