Pure curcumin decreases the expression of WT1 by upregulation of miR-15a and miR-16-1 in leukemic cells

Background: pure curcumin has been reported to down-regulate the expression of wt1 in leukemic cells. however,the molecular mechanism underlying the down-regulation of wt1 by curcumin is not completely delineated. the purpose of this present study is to identify a new mirna-mediated mechanism which plays an important role in the anti-proliferation effects of curcumin in leukemic cells. methods. k562 and hl-60 cells were treated with different concentrations of curcumin for 24 and 48 hours,the level of mir-15a/16-1 and wt1 were detected by qrt-pcr and western blotting. wt1 expression and cell proliferation were detected by western blotting and cck-8,after curcumin treated-k562 and hl-60 cells were transfected with anti-mir-15a/16-1 oligonucleotides. results: we found that pure curcumin upregulated the expression of mir-15a/16-1 and downregulated the expression of wt1 in leukemic cells and primary acute myeloid leukemia (aml) cells. overexpression of mir-15a/16-1 deduced the protein level of wt1 in leukemic cells,but downregulation of wt1 by sirna-wt1 could not increase the expression of mir-15a/16-1 in leukemic cells. these results reveal that curcumin induced-upregulation of mir-15a/16-1 is an early event upstream to downregulation of wt1. furthermore,anti-mir-15a/16-1 oligonucleotides (amo) partly reversed the downregulation of wt1 induced by pure curcumin in leukemic cells and amo promoted the growth of curcumin treated-k562 and hl-60 cells. conclusion: thus,these data suggest for the first time that pure curcumin downregulated the expression of wt1 partly by upregulating the expression of mir-15a/16-1 in leukemic cells. mir-15a/16-1 mediated wt1 downregulation plays an important role in the anti-proliferation effect of curcumin in leukemic cells. © 2012 gao et al; licensee biomed central ltd.