Melanoma biomarkers: current status and utility in diagnosis, prognosis, and response to therapy

Flubendazole Plays an Important Anti-Tumor Role in Different Types of Cancers

Flubendazole, belonging to benzimidazole, is a broad-spectrum insect repellent and has been repurposed as a promising anticancer drug. In recent years, many studies have shown that flubendazole plays an anti-tumor role in different types of cancers, including breast cancer, melanoma, prostate cancer, colorectal cancer, and lung cancer. Although the anti-tumor mechanism of flubendazole has been studied, it has not been fully understood. In this review, we summarized the recent studies regarding the anti-tumor effects of flubendazole in different types of cancers and analyzed the related mechanisms, in order to provide the theoretical reference for further studies in the future.

Nomogram Incorporating the WNT/β-Catenin Signaling Pathway for Predicting the Survival of Cutaneous Melanoma

Background

Accurate prediction of the survival of cutaneous melanoma (CM) permits the selection of the optimal treatment. Currently, the TNM stage has limitations in predicting the survival of CM. There is evidence that the WNT/β-catenin signaling pathway has the potential to predict the CM prognosis. However, it still needs further investigation.

Objective

This study aims to establish a nomogram incorporating the WNT/β-catenin signaling pathway to improve the predicted accuracy of the overall survival (OS) of CM.

Methods

Two hundred and eighty CM patients were recruited and followed up. The clinicopathological characteristics and the key genes of the WNT/β-catenin signaling pathway (VEGF, β-catenin, and DKK1) were chosen as potential variables associated with the OS. In the training cohort (n = 190), a nomogram was built to estimate the 1-, 3-, and 5-year OS, and its discriminations and calibrations were valid by the verification cohort (n = 90). The predicted accuracies of the nomogram with or without the Wnt/β-catenin pathway and TNM stage were compared.

Results

A nomogram integrating independent risk factors (ulceration, lymph node metastasis, distant metastasis, Breslow thickness, dermal mitoses, β-catenin, VEGF, and DKK1), which were evaluated by a multivariate analysis, was constructed to predict the 1-, 3-, and 5-year OS of CM patients. Good discrimination and calibration were obtained regardless of the training or validation datasets. The nomogram incorporating the Wnt/β-catenin signaling pathway showed the highest accuracy [area under the curve (AUC)=0.914, 0.852, 0.785] compared with the nomogram without the Wnt/β-catenin signaling pathway (AUC=0.693, 0.640, 0.615) and the TNM stage (AUC=0.726, 0.693, 0.673).

Conclusion

The prognostic value of the established nomogram incorporating the WNT/β-catenin signaling pathway was better than it without WNT/β-catenin signaling pathway and TNM stage, which might be beneficial in the development of optimal treatment options.

Using global gene expression to discriminate thin melanomas with poor outcomes

Most melanomas present as thin lesions (≤1.0 mm) with a good prognosis; however, a small percentage of patients with thin lesions experience recurrence or metastasis. The aim of our study was to identify a distinct pattern of gene expression within thin melanomas known to have eventually metastasized to regional lymph nodes or distant sites compared with those that followed the typical course with good response to wide local excision alone. Patients who were disease-free for a minimum of 10 y served as controls (n = 10) to the experimental group who developed metastasis (n = 9). Laser capture microdissection was used to specifically isolate cancer cells from formalin-fixed paraffin-embedded tissue with subsequent gene expression analysis on Affymetrix Human Transcriptome Array 2.0 Arrays. Although gene expression differences were observed between the patients with thin melanoma with poor clinical outcome and those with good clinical outcome, neither the number of genes nor the magnitude of the fold difference was very substantial or significant. Cluster analysis with this subset of genes could definitively separate a subset of the poor responders from the good responders, but there remained a mixed group of tumors that could not be predicted from gene expression alone. Pathway analysis identified cellular processes that were regulated based on the response, including categories commonly associated with melanoma progression. Ultimately, we concluded that there were very few differences between these groups. Future research will be required and investigation of the mutational landscape may be another strategy to uncover genomic changes that drive recurrence and metastasis in thin melanoma.

Molecular subtyping of metastatic melanoma based on cell ganglioside metabolism profiles

BACKGROUND

In addition to alterations concerning the expression of oncogenes and onco-suppressors, melanoma is characterized by the presence of distinctive gangliosides (sialic acid carrying glycosphingolipids). Gangliosides strongly control cell surface dynamics and signaling; therefore, it could be assumed that these alterations are linked to modifications of cell behavior acquired by the tumor. On these bases, this work investigated the correlations between melanoma cell ganglioside metabolism profiles and the biological features of the tumor and the survival of patients.

METHODS

Melanoma cell lines were established from surgical specimens of AJCC stage III and IV melanoma patients. Sphingolipid analysis was carried out on melanoma cell lines and melanocytes through cell metabolic labeling employing [3-3H]sphingosine and by FACS. N-glycolyl GM3 was identified employing the 14 F7 antibody. Gene expression was assayed by Real Time PCR. Cell invasiveness was assayed through a Matrigel invasion assay; cell proliferation was determined through the soft agar assay, MTT, and [3H] thymidine incorporation. Statistical analysis was performed using XLSTAT software for melanoma hierarchical clustering based on ganglioside profile, the Kaplan-Meier method, the log-rank (Mantel-Cox) test, and the Mantel-Haenszel test for survival analysis.

RESULTS

Based on the ganglioside profiles, through a hierarchical clustering, we classified melanoma cells isolated from patients into three clusters: 1) cluster 1, characterized by high content of GM3, mainly in the form of N-glycolyl GM3, and GD3; 2) cluster 2, characterized by the appearance of complex gangliosides and by a low content of GM3; 3) cluster 3, which showed an intermediate phenotype between cluster 1 and cluster 3. Moreover, our data demonstrated that: a) a correlation could be traced between patients' survival and clusters based on ganglioside profiles, with cluster 1 showing the worst survival; b) the expression of several enzymes (sialidase NEU3, GM2 and GM1 synthases) involved in ganglioside metabolism was associated with patients' survival; c) melanoma clusters showed different malignant features such as growth in soft agar, invasiveness, expression of anti-apoptotic proteins.

CONCLUSIONS

Ganglioside profile and metabolism is strictly interconnected with melanoma aggressiveness. Therefore, the profiling of melanoma gangliosides and enzymes involved in their metabolism could represent a useful prognostic and diagnostic tool.

A purine nucleotide biosynthesis enzyme guanosine monophosphate reductase is a suppressor of melanoma invasion

Melanoma is one of the most aggressive types of human cancers, and the mechanisms underlying melanoma invasive phenotype are not completely understood. Here, we report that expression of guanosine monophosphate reductase (GMPR), an enzyme involved in de novo biosynthesis of purine nucleotides, was downregulated in the invasive stages of human melanoma. Loss- and gain-of-function experiments revealed that GMPR downregulates the amounts of several GTP-bound (active) Rho-GTPases and suppresses the ability of melanoma cells to form invadopodia, degrade extracellular matrix, invade in vitro, and grow as tumor xenografts in vivo. Mechanistically, we demonstrated that GMPR partially depletes intracellular GTP pools. Pharmacological inhibition of de novo GTP biosynthesis suppressed whereas addition of exogenous guanosine increased invasion of melanoma cells as well as cells from other cancer types. Our data identify GMPR as a melanoma invasion suppressor and establish a link between guanosine metabolism and Rho-GTPase-dependent melanoma cell invasion.

Odontogenic ameloblast-associated protein (ODAM) inhibits growth and migration of human melanoma cells and elicits PTEN elevation and inactivation of PI3K/AKT signaling

Background

The Odontogenic Ameloblast-associated Protein (ODAM) is expressed in a wide range of normal epithelial, and neoplastic tissues, and we have posited that ODAM serves as a novel prognostic biomarker for breast cancer and melanoma. Transfection of ODAM into breast cancer cells yields suppression of cellular growth, motility, and in vivo tumorigenicity. Herein we have extended these studies to the effects of ODAM on cultured melanoma cell lines.

Methods

The A375 and C8161 melanoma cell lines were stably transfected with ODAM and assayed for properties associated with tumorigenicity including cell growth, motility, and extracellular matrix adhesion. In addition, ODAM–transfected cells were assayed for signal transduction via AKT which promotes cell proliferation and survival in many neoplasms.

Results

ODAM expression in A375 and C8161 cells strongly inhibited cell growth and motility in vitro, increased cell adhesion to extracellular matrix, and yielded significant cytoskeletal/morphologic rearrangement. Furthermore, AKT activity was downregulated by ODAM expression while an increase was noted in expression of the PTEN (phosphatase and tensin homolog on chromosome 10) tumor suppressor gene, an antagonist of AKT activation. Increased PTEN in ODAM-expressing cells was associated with increases in PTEN mRNA levels and de novo protein synthesis. Silencing of PTEN expression yielded recovery of AKT activity in ODAM-expressing melanoma cells. Similar PTEN elevation and inhibition of AKT by ODAM was observed in MDA-MB-231 breast cancer cells while ODAM expression had no effect in PTEN-deficient BT-549 breast cancer cells.

Conclusions

The apparent anti-neoplastic effects of ODAM in cultured melanoma and breast cancer cells are associated with increased PTEN expression, and suppression of AKT activity. This association should serve to clarify the clinical import of ODAM expression and any role it may serve as an indicator of tumor behavior.

Racial differences in survival after surgical treatment for melanoma

BACKGROUND

Surgical-treatment outcomes for melanoma in African Americans are poorly characterized as a result of low incidence of melanoma among African Americans. We examined differences by race in overall and melanoma-specific survival, stratified by receipt of surgical treatment and by specific types of surgical treatment.

METHODS

Data from the 1973-2004 public-use Surveillance, Epidemiology and End Results Program (SEER) were analyzed by Cox proportional hazard models to compare the effects of surgical treatments on overall and melanoma-specific survival in blacks, whites, and other race, controlling for confounding demographic and tumor-related variables.

RESULTS

Of 151,154 patients with first primary melanoma (148,883 whites, 789 blacks and 1,532 other race), 142,653 (94.4%) received surgical treatment. Among patients who received surgical treatment, 10-year melanoma-specific survival was lower in blacks (73%) than in whites (88%) and other race (85%); black patients were at significantly higher risk of overall and melanoma-specific mortality when compared with white (hazard ratio [HR] = 1.64, 95% confidence interval [CI] 1.44-1.86, P < 0.0001 and HR = 1.50, 95% CI 1.25-1.79, P < 0.0001, respectively) and with other race (HR = 1.55, 95% CI 1.31-1.85, P < 0.0001 and HR = 1.49, 95% CI 1.16-1.91, P = 0.0017, respectively). Blacks who underwent biopsy, wide excision and surgery not otherwise specified were at higher risk of overall mortality compared with whites with the same treatment.

CONCLUSION

Overall and melanoma-specific survival was lower in blacks undergoing surgical treatment for melanoma compared to both whites and other race. Reasons for these disparities remain poorly understood.

Melanoma progression exhibits a significant impact on connexin expression patterns in the epidermal tumor microenvironment

Melanoma depends on, interacts with and reacts to the stroma in which it is embedded, including fibroblasts, extracellular matrix, endothelial cells and immune cells. However, the impact of melanoma on the epidermal tumor microenvironment-the multilayered epithelium of the skin-is poorly understood. Gap junctions are essential for intercellular communication and involved in proliferation, differentiation and homeostasis of keratinocytes. We have shown previously that the gap junction proteins connexin 26 and 30 (Cx26 and Cx30) are induced in the epidermal tumor microenvironment of skin cancers including melanoma. This study compares the extent of Cx26, Cx30 and Cx43 expression in the epidermal microenvironment of melanocytic nevi and melanomas and its association with melanoma thickness, proliferative index of the tumor and its microenvironment, and with 5-year metastasis and survival. We found that induction of Cx26 and Cx30 cell-cell border expression in the epidermal tumor microenvironment correlates to malignancy. Importantly, there was a significant correlation of tumor thickness with the vertical epidermal Cx26 and Cx30 expression pattern and the horizontal Cx26 dissemination. Furthermore, horizontal Cx26 expression correlated with metastasis. Vertical epidermal expression patterns of Cx26 and Cx30 significantly correlated with the proliferative index in the epidermal tumor microenvironment but not with the proliferative index in the tumor. In contrast, Cx43 did not correlate with malignancy, thickness or proliferative index. In summary, here we show for the first time a significant association between the progression of melanoma and alterations in its epithelial tumor microenvironment.