FIGURE 5.

PLL and TPF treatments suppress the tumorigenic activity of miR-93 overexpressing NIH3T3 cells. A, 3T3-miR-93 cells transfected with FLAG·AGO2 were treated with PLL or TPF, or were untreated (−) for 3 days and then recovered for small RNA as described in Fig. 4. miR-93 in miRNA(T) and miRNA(A) was quantified, and the ratios of miRNA(A)/miRNA(T) are also shown. B, 3T3-miR-93 cells treated with 2 μm PLL, 1 μm TPF, or untreated were observed in a soft agar growth assay. Representative images are shown. C, 3T3-miR-93 cells were pretreated without or with PLL or TPF for 3 days and subsequently implanted into nude mice subcutaneously for observation of tumor formation. Treated cells did not form tumors in mice. Representative pictures of mice are shown. D, cell growth of HTLV-I-infected leukemic cell lines and normal PBMCs upon PLL and TPF treatment. Cell proliferation was examined by MTT assay on HTLV-1-cells, MT1, MT4, and ED, or on normal PBMC treated with 3 μm PLL, 3 μm TPF, or untreated (−) for 4 days. MT1, MT4, and ED cells all overexpress miR-93 and miR-130b. The A₄₅₀ value for the untreated sample was set as 1 for each cell type. Treatment with PLL and TPF reduced the growth of HTLV-1-cells compared with normal PBMCs.