It is has been hypothesized that
methylselenol is a critical
selenium metabolite for anticancer activity in vivo. In this study, we used a
protein array which contained 112 different
antibodies known to be involved in the p53 pathway to investigate the molecular targets of
methylselenol in human HCT116
colon cancer cells. The array analysis indicated that
methylselenol exposure changed the expression of 11
protein targets related to the regulation of cell cycle and apoptosis. Subsequently, we confirmed these
proteins with the Western blotting approach, and found that
methylselenol increased the expression of GADD 153 and p21 but reduced the level of c-Myc, E2F1 and Phos
p38 MAP kinase. Similar to our previous report on human HCT116
colon cancer cells,
methylselenol also inhibited cell growth and led to an increase in G1 and G2 fractions with a concomitant drop in S-phase in mouse
colon cancer MC26 cells. When the MC26 cells were transplanted to their immune-competent Balb/c mice,
methylselenol-treated MC26 cells had significantly less
tumor growth potential than that of untreated MC26 cells. Taken together, our data suggest that
methylselenol modulates the expression of key genes related to cell cycle and apoptosis and inhibits
colon cancer cell proliferation and
tumor growth.