Cutaneous melanoma: available therapy for metastatic disease

Melanoma biology and new targeted therapy

Melanoma is a cancer that arises from melanocytes, specialized pigmented cells that are found predominantly in the skin. The incidence of melanoma is rising steadily in western populations--the number of cases worldwide has doubled in the past 20 years. In its early stages malignant melanoma can be cured by surgical resection, but once it has progressed to the metastatic stage it is extremely difficult to treat and does not respond to current therapies. Recent discoveries in cell signalling have provided greater understanding of the biology that underlies melanoma, and these advances are being exploited to provide targeted drugs and new therapeutic approaches.

Roscovitine Inhibits Differentiation and Invasion in a Three-Dimensional Skin Reconstruction Model of Metastatic Melanoma

The aim of this study was to investigate the therapeutic potential of a cyclin-dependent kinase inhibitor, roscovitine, in cultured melanoma cells and a three-dimensional skin reconstruction model of metastatic melanoma. The modulatory effects of roscovitine on the growth and survival of normal melanocytes and cultured melanoma cell lines were tested. Additionally, we investigated the potential of roscovitine to regulate the growth and differentiation of a metastatic melanoma cell line (A375) in a three-dimensional skin reconstruction culture consisting of A375 cells admixed with normal human keratinocytes embedded within a collagen-constricted fibroblast matrix. We show that roscovitine is able to induce apoptosis in the melanoma cell lines A375, 888, and 624 but not in normal human cultured epithelial melanocytes. The degree of apoptosis within these cell lines correlated with the accumulation of p53 protein and concomitant reduction of X-linked inhibitor of apoptosis protein, with no change in the proteins Bcl-2 and survivin. We also found that roscovitine inhibited the growth and differentiation of A375 melanoma cells within the dermal layer of the skin. The results of this study show that roscovitine has the potential to inhibit the differentiation and invasion of metastatic melanoma and may be useful as a therapy for the treatment of patients with metastatic melanoma.

New technologies used in the study of human melanoma

The amount of information on tumor biology has expanded enormously, essentially due to the completion of the human genome sequencing and to the application of new technologies that represent an exciting breakthrough in molecular analysis. Often these data spring from experimental procedures, such as a serial analysis of gene expression (SAGE) and DNA microarrays, which cannot be defined as hypothesis-driven: it may appear to be a "brute force" approach through which no information can be directly generated concerning the specific functions of selected genes in a definite context. However, interesting results are fruitfully generated, and thus it is important to consider the enormous potential these new technologies possess and to learn how to apply this novel form of knowledge in the emerging field of molecular medicine. This review, after a limited outline regarding several classic aspects of human cutaneous melanoma biology, genetics, and clinical approaches, will focus on the proficient use of up-to-date technologies in the study of the neoplastic disease and on their capability to provide effective support to conventional approaches in melanoma diagnosis, prognosis, and treatment.

Dacarbazine induces genotoxic and cytotoxic germ cell damage with concomitant decrease in testosterone and increase in lactate dehydrogenase concentration in the testis

Treatment of cancers with cytotoxic agents such as alkylating drugs often, but not always results in transient to permanent testicular dysfunction. The present study was planned to investigate the effects of dacarbazine [5-(3,3-dimethyltriazeno) imidazole-4-carboxamide] on testicular function in mice. Swiss albino mice (9-12 weeks old) were treated with 0, 5, 25, 50, or 100mg/kg body weight/day dacarbazine (i.p.) for 5 days at intervals of 24h between treatments. Mice were sacrificed on days 7, 14, 21, 28, 35, 49, and 70 after the last treatment (6 mice/dose/sample time), and the epididymal sperm count, sperm motility, sperm morphology, testicular histopathology (qualitative histopathology, seminiferous tubular diameter and epithelial height), and intra-testicular levels of testosterone and lactate dehydrogenase were assessed. Dacarbazine decreased the body weight only on day 28 at 25mg/kg dose-level, but increased the paired testes weights at 50mg/kg on day 7, at 25-100mg/kg on day 14, and at 25 and 50mg/kg on day 21 (P<0.05-0.01; one-way ANOVA and Bonferroni's post hoc test). The sperm count was decreased on all sampling days except at 5 and 25mg/kg dose-levels on day 70, but with severe oligospermia on days 28 and 35 (P<0.05-0.001). The sperm motility was decreased at 100mg/kg on days 14 and 21, at 5, 25, and 100mg/kg on day 28, and at all dose-levels on day 35 (P<0.05-0.001). Dacarbazine induced both head and tail abnormalities and some sperms with cytoplasmic droplets, but significant increase was seen in all dose groups on days 14 and 21, and at 100mg/kg dose-level on day 35. Drug-induced epithelial sloughing was seen on days 14-35 and other histopathological changes observed were vacuoles and abnormal cells. The STD was increased at 25-100mg/kg on day 7, at all dose-levels on day 14, at 50-100mg/kg on days 21 and 28, but without any effects on days 35-70 (P<0.05-0.001), and the tubular lumen was found dilated. The SE was increased on days 7, 21 and 28 at 100mg/kg and on day 14 at 50-100mg/kg. Dacarbazine reduced the intra-testicular testosterone level at 100mg/kg on day 7, at 5, 50 and 100mg/kg on day 14, at all dose-levels on days 21, 28, and 35, and at 50mg/kg on day 49 (P<0.05-0.001). The intra-testicular lactate dehydrogenase concentration increased at all dose-levels up to day 35, but without any effect on days 49 and 70 (P<0.05-0.001). There was no particular dose-response of dacarbazine on any parameters tested. The sperm count (except on day 7-positive correlation; Pearson product moment correlation) or sperm motility did not have any relation but increase in abnormal sperms showed negative correlation with decrease in testosterone level on days 7, 21 and 28. Decrease in sperm count was in negative correlation on days 14 and 35, and increase in abnormal sperms showed positive correlation on day 35 with increase in LDH level. Finally, the decrease in sperm motility had no correlation with increase in abnormal sperm shapes. We conclude that dacarbazine is genotoxic and cytotoxic to the mouse testis in a transient fashion, and these effects are exerted along with decrease in testosterone and increase in lactate dehydrogenase levels in the testis.