calcipotriene and Melanoma

Deregulated melanogenesis is involved in melanomagenesis and melanoma progression and resistance to therapy. Vitamin D analogs have anti-melanoma activity. While the hypercalcaemic effect of the active form of Vitamin D (1,25(OH)2D3) limits its therapeutic use, novel Vitamin D analogs with a modified side chain demonstrate low calcaemic activity. We therefore examined the effect of secosteroidal analogs, both classic (1,25(OH)2D3 and 25(OH)D3), and novel relatively non-calcemic ones (20(OH)D3, calcipotriol, 21(OH)pD, pD and 20(OH)pL), on proliferation, colony formation in monolayer and soft-agar, and mRNA and protein expression by melanoma cells. Murine B16-F10 and hamster Bomirski Ab cell lines were shown to be effective models to study how melanogenesis affects anti-melanoma treatment. Novel Vitamin D analogs with a short side-chain and lumisterol-like 20(OH)pL efficiently inhibited rodent melanoma growth. Moderate pigmentation sensitized rodent melanoma cells towards Vitamin D analogs, and altered expression of key genes involved in Vitamin D signaling, which was opposite to the effect on heavily pigmented cells. Interestingly, melanogenesis inhibited ligand-induced Vitamin D receptor translocation and ligand-induced expression of VDR and CYP24A1 genes. These findings indicate that melanogenesis can affect the anti-melanoma activity of Vitamin D analogs in a complex manner.

Topics: Animals; Antineoplastic Agents; Calcitriol; Cell Line, Tumor; Cell Proliferation; Cricetinae; Gene Expression Regulation, Neoplastic; Melanins; Melanoma; Mice; Receptors, Calcitriol; Signal Transduction; Skin Neoplasms; Vitamin D; Vitamin D3 24-Hydroxylase

With increasing incidence of non-melanoma skin cancer (NMSC), focus on chemoprevention of this disease is growing. The aim of this study was to evaluate topical combination therapies as chemoprevention of UV radiation-induced tumors in a mouse model.. A total of 160 SKH-1 mice were randomized to one placebo group and four chemoprevention groups (diclofenac plus difluoromethylornithine; diclofenac plus calcipotriol; difluoromethylornithine plus calcitriol; and diclofenac plus difluoromethylornithine plus calcipotriol). The mice received UVB radiation for 20 weeks followed by 17 weeks with topical application of chemoprevention. The number of mice with tumors, number of tumors per group and tumor area size were compared using a linear regression model.. Chemoprevention with diclonefac plus calcipotriol and diclonefac plus difluoromethylornithine had a significant inhibiting effect on the number of tumors per group and the area of tumors. Moreover, diclonefac plus difluoromethylornithine had a significant inhibiting effect on the number of mice with tumors.. Potentially, non-melanoma skin cancer in humans may be prevented with these agents with few adverse effects. Therefore, clinical studies are needed to determine their therapeutic/preventive effect and possible adverse effects.

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Body Weight; Calcitriol; Chemoprevention; Diclofenac; Eflornithine; Female; Melanoma; Mice; Precancerous Conditions; Skin Neoplasms; Survival Analysis

Topics: Calcitriol; Dermatologic Agents; Humans; Hyperpigmentation; Male; Melanoma; Middle Aged; Psoriasis; Skin Neoplasms