AK4 expression levels were markedly decreased in both MCF7 and MDA-MB-231 cells caused by its shRNA transfection. (a) Quantitative PCR assays showed the dramatically reduced expression levels of AK4 after the transfection of its shRNA in MCF7 and MDA-MB-231 cells, respectively. (b) Immunoblot assays showed the efficient decrease of AK4 expression caused by the transfection of its shRNA plasmids in both MCF7 and MDA-MB-231 cells. Results are presented as mean ± SD, ∗ P
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