Fig. 2.

FEN1 is essential for cell proliferation and contributes to drug resistance in cancer cells. FEN1 was (a) knocked-down in MCF7 or (b) overexpressed in MCF10A cells. The expression level of FEN1 was determined by western blot analysis using anti-FEN1 antibody. Cell growth rate assay of cells in which FEN1 was (c) suppressed or (d) overexpressed. Foci formation assay in cells with (e) FEN1 suppression or (f) overexpression. g. FEN1 knockdown sensitizes MCF7 cells to temozolomide (TMZ). h. FEN1overexpression inMCF10A cells caused increased resistance to TMZ. Cells with FEN1downregulation (i) or FEN1 overexpression (j) were harvested and stained, and the percentage of sub-G1 fraction was determined by flow cytometry.