Medicine and Health Sciences Commons^™

Vitamin A (Retinoids) Regulation Of Mouse Melanoma Growth And Differentiation, Richard Niles

Richard M Niles

The incidence of melanoma is rapidly increasing in the U.S. population. At the present, there is no effective chemotherapy against invasive melanoma. At our laboratory, we have been studying retinoic acid (RA)-induced growth arrest and differentiation in the B16 murine melanoma cell model. Several immediate-early gene targets of RA were identified by gene arrays. In one of these genes, T-box binding protein-2 (Tbx-2), an RA response element, was identified in the promoter region that mediates the RA responsiveness of this gene. RA also induces a sixfold to eightfold increase in protein kinase C (PKC)α RNA and protein. This gene is …

Silencing And Re-Expression Of Retinoic Acid Receptor Beta2 In Human Melanoma, Jun Fan, Linda Eastham, Melinda Varney, Adam Hall, Nicolas Adkins, Vincent Sollars, Philippe Georgel, Richard Niles

Richard M Niles

Many melanoma cells are resistant to the anti-proliferative effect of all trans retinoic acid (ATRA). Retinoic Acid Receptor-β2 (RAR-β2) mediates the ATRA growth inhibition. We found a correlation between the anti-proliferative activity of ATRA and expression of RAR-β2. There was not a strict correlation between DNA methylation of RAR-β gene and its expression. There was no difference in global and RARβ specific nucleosome repeat length (NRL) in melanoma and melanocytes or between control and ATRA treated cells. Pan-acetylation of H3 and H4 within the RAR-β gene promoter was higher in cells expressing RAR-β2. All trans retinoic acid treatment of …

Expression And Function Of Cd9 In Melanoma Cells, Jun Fan, Guo-Zhang Zhu, Richard Niles

Richard M Niles

CD9, a member of the tetraspanin family, functions as an organizer in “tetraspanin webs,” through interacting with other cell adhesion molecules. It plays a role in differentiation, fertilization, and cell migration. We investigated the expression and function of CD9 in melanoma. CD9 protein expression in B16 mouse melanoma and six human melanoma cell lines was decreased compared to normal melanocytes. B16F1 clones stably overexpressing CD9 had reduced ability to form colonies in soft agar; however, paradoxically these overexpressing clones had increased ability to invade Matrigel. Similarly, transient overexpression of CD9 in the human metastatic melanoma cell line WM9 dramatically decreased …

Resveratrol Is Rapidly Metabolized In Athymic (Nu/Nu) Mice And Does Not Inhibit Human Melanoma Xenograft Tumor Growth, Richard Niles, Carla Cook, Gary Meadows, Ya-Min Fu, Jerry Mclaughlin, Gary Rankin

Richard M Niles

Resveratrol has been shown to have anticarcinogenic activity. We previously found that resveratrol inhibited growth and induced apoptosis in 2 human melanoma cell lines. In this study we determined whether resveratrol would inhibit human melanoma xenograft growth. Athymic mice received control diets or diets containing 110 μmol/L or 263 μmol/L resveratrol, 2 wk prior to subcutaneous injection of the tumor cells. Tumor growth was measured during a 3-wk period. Metabolism of resveratrol was assayed by bolus gavage of 75 mg/kg resveratrol in tumor-bearing and nontumor-bearing mice. Pellets containing 10–100 mg resveratrol were implanted into the mice, next to newly palpated …

Pparα/Γ Expression And Activity In Mouse And Human Melanocytes And Melanoma Cells, Linda Eastham, Caroline Mills, Richard Niles

Richard M Niles

Purpose. We examined the expression of PPARs and the effects of PPARα and PPARγ agonists on growth of mouse and human melanocytes and melanoma cells.

Methods. PPARα,β, and PPARγ mRNA qualitative expression in melan-a mouse melanocytes, B16 mouse melanoma, human melanocytes, and A375 and SK-mel28 human melanoma cells was determined by RT-PCR, while quantitative PPARα mRNA levels were determined by QuantiGene assay. PPARα and PPARγ protein was assessed by Western blotting. The effect of natural and synthetic PPAR ligands on cell growth was determined by either hemocytometer counting or crystal violet assay. PPAR transcriptional activity was determined by a PPRE-reporter …