Fig 2: Downregulation of METTL3 expression increases apoptosis in human ovarian cancer cells. (A and B) Quantification of Annexin V/PI staining in SKOV3 cells transfected with shMETTL3 or NC. (C and D) Quantification of Annexin V/PI staining in OVCAR3 cells transfected with shMETTL3 or NC. The data were analyzed by using FlowJo version 10 software. (E and F) Bcl2, Bax and Caspase 3 protein expression levels in SKOV3 and OVCAR3 cells with treated with shMETTL3 or NC. All experiments were performed in triplicate. *P<0.05 vs. NC. METTL3, methyltransferase-like 3; sh, short hairpin; NC, negative control; PI, propidium iodide.

Fig 3: METTL3 knockdown inhibits cell invasion and may reduce the activation of the AKT signaling pathway. (A and B) Quantified cell migration and invasion of SKOV3 and OVCAR3 cells treated with shMETTL3 or NC. (C and D) Expression of the components of the AKT signaling pathway, including AKT, p-AKT, p7026K and Cyclin D1, in SKOV3 and OVCR3 cells treated with shMETTL3 or NC. All experiments were performed in triplicate. Scale bar, 100 µm. *P<0.05 vs. NC. METTL3, methyltransferase-like 3; sh, short hairpin; NC, negative control; p-, phosphorylated.

Fig 4: Downregulation of METTL3 expression inhibits proliferation and colony formation of human ovarian cancer cells. (A) Proliferation of SKOV3 cells treated with shMETTL3 or NC at different time points. (B) Proliferation of OVCAR3 cells treated with shMETTL3 or NC at different time points. (C and D) Colony formation of SKOV3 and OVCAR3 cells treated with shMETTL3 or NC. All experiments were performed in triplicate. *P<0.05 vs. NC. METTL3, methyltransferase-like 3; sh, short hairpin; NC, negative control.

Fig 5: METTL3 expression levels are high ovarian cancer tissues. Areas indicated by arrows indicate sites of high METTL3 expression levels. (A-D) Immunohistochemical staining of METTL3 in ovarian cancer tissues and para-carcinoma in cases of: (A) serous adenocarcinoma, (B) mucinous adenocarcinoma, (C) endometrioid adenocarcinoma and (D) clear cell carcinoma. Magnifications, ×100 and ×400. Scale bars, 100 and 400 µm. METTL3, methyltransferase-like 3.