Figure 4. As an oncogenic gene, WTAP is more expressed in EC cells than that in normal cells, and regulates cell proliferation and apoptosis under normoxic and hypoxic conditions. (A) The expression levels of WTAP in esophageal cancer tissues and the adjacent normal tissues were determined by RT-qPCR, n=20 for each group. (B) Compared with normal esophageal epithelial HET1A cell, esophageal cancer cell lines (EC9706, ECA-109, KYSE150, KYSE450, TE1 and TE10) expressed more WTAP transcript, as revealed by RT-qPCR assays. n=5 for each group. (C) Over-expression or knockdown of WTAP in ECA-109 cells was confirmed by western blot assays at 48 hours after the indicated treatments. n=5 for each group. (D) Cell proliferations of indicated cells at 96 hours after treatments were measured with CCK-8 assays during a period of 4 days growth. Here, comparisons were performed between sh-NC vs. sh-WTAP and pcDNA-Empty vs. pcDNA-WTAP, respectively. n=5 for each group. (E, F) The representative flow profile of Annexin V/PI staining for indicated cells at 48 hours after treatments are shown (E), and summarized results on apoptosis are shown in the bar graph (F). n=5 for each group. (G, H) WTAP knockdown diminished the drug resistance of ECA-109 cells to DDP under hypoxic condition. The results on cell proliferation, as revealed by CCK-8 assays (G), and apoptosis, as revealed by annexin V-flow staining (H), are shown. n=3 for each group.