The role of melanogenesis in regulation of melanoma behavior: melanogenesis leads to stimulation of HIF-1α expression and HIF-dependent attendant pathways.

To study the effect of melanogenesis on HIF-1α expression and attendant pathways, we used stable human and hamster melanoma cell lines in which the amelanotic vs. melanotic phenotypes are dependent upon the concentration of melanogenesis precursors in the culture media. The induction of melanin pigmentation led to significant up-regulation of HIF-1α, but not HIF-2α, protein in melanized cells for both lines. Similar upregulation of nuclear HIF-1α was observed in excisions of advanced melanotic vs. amelanotic melanomas. In cultured cells, melanogenesis also significantly stimulated expression of classical HIF-1-dependent target genes involved in angiogenesis and cellular metabolism, including glucose metabolism and stimulation of activity of key enzymes in the glycolytic pathway. Several other stress related genes containing putative HRE consensus sites were also upregulated by melanogenesis, concurrently with modulation of expression of HIF-1-independent genes encoding for steroidogenic enzymes, cytokines and growth factors. Immunohistochemical studies using a large panel of pigmented lesions revealed that higher levels of HIF-1α and GLUT-1 were detected in advanced melanomas in comparison to melanocytic nevi or thin melanomas localized to the skin. However, the effects on overall or disease free survival in melanoma patients were modest or absent for GLUT-1 or for HIF-1α, respectively. In conclusion, induction of the melanogenic pathway leads to robust upregulation of HIF-1-dependent and independent pathways in cultured melanoma cells, suggesting a key role for melanogenesis in regulation of cellular metabolism.

High basal NF-κB activity in nonpigmented melanoma cells is associated with an enhanced sensitivity to vitamin D3 derivatives.

BACKGROUND: Melanoma is highly resistant to current modalities of therapy, with the extent of pigmentation playing an important role in therapeutic resistance. Nuclear factor-κB (NF-κB) is constitutively activated in melanoma and can serve as a molecular target for cancer therapy and steroid/secosteroid action. METHODS: Cultured melanoma cells were used for mechanistic studies on NF-κB activity, utilising immunofluorescence, western blotting, EMSA, ELISA, gene reporter, and estimated DNA synthesis assays. Formalin-fixed, paraffin-embedded specimens from melanoma patients were used for immunocytochemical analysis of NF-κB activity in situ. RESULTS: Novel 20-hydroxyvitamin (20(OH)D(3)) and classical 1α,25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3)) secosteroids inhibited melanoma cell proliferation. Active forms of vitamin D were found to inhibit NF-κB activity in nonpigmented cells, while having no effect on pigmented cells. Treatment of nonpigmented cells with vitamin D3 derivatives inhibited NF-κB DNA binding and NF-κB-dependent reporter assays, as well as inhibited the nuclear translocation of the p65 NF-κB subunit and its accumulation in the cytoplasm. Moreover, analysis of biopsies of melanoma patients showed that nonpigmented and slightly pigmented melanomas displayed higher nuclear NF-κB p65 expression than highly pigmented melanomas. CONCLUSION: Classical 1,25(OH)(2)D(3) and novel 20(OH)D(3) hydroxyderivatives of vitamin D3 can target NF-κB and regulate melanoma progression in nonpigmented melanoma cells. Melanin pigmentation is associated with the resistance of melanomas to 20(OH)D(3) and 1,25(OH)(2)D(3) treatment.

Diagnostic value of urine cytology and urine carcinoembryonic antigen (CEA) level in the distinction between bladder cancer and urinary tract infection.

In the retrospective investigation we estimated the CEA levels in urine and urine cytology in 293 patients with urinary bladder cancer (group I) and in 129 patients with urinary tract infection (group II). An increased CEA level was found in 212 cases of bladder cancer and in 109 cases of urinary infection. Neoplastic cells in urine sediment were identified in 254 cases in the first group, while in the second, multiple inflammatory cells and pyuria were diagnosed in 55 and 56 cases, respectively. The combined examination (increased CEA level and/or positive cytology of the urine sediment) allowed for the diagnosis of neoplastic disease in 270 patients in the first group and infection diseases in 123 patients in the second group. After surgical therapy an increased urine CEA level and neoplastic cells in the urine cytology were found in 1 case which was then confirmed histopathologically. In the group with urinary infection an increased CEA level in urine, after antiphlogistic therapy, was found in 5 cases, inflammatory cells in 12 cases, pyuria in 8 cases and suspect cells were found in 6 cases in the group with urinary infection. In specimens from these cases, after electroresection, bladder cancer was diagnosed in 2, and cystitis cystica type changes in 2 cases.