The hEM15A cells were lysed in RIPA buffer (Sigma, USA) containing protease inhibitor cocktail (Sigma). Then, proteins were isolated using 10% SDS-PAGE gels, transferred onto PVDF membranes (Millipore, USA), and blocked with nonfat milk (5%) at room temperature for 2 h. Afterward, the membranes were incubated with specific primary antibodies against CDK2 (ab32147, 1:1000; Abcam, USA), CDK4 (ab137675, 1:1000), CDK6 (ab124821, 1:1000), Cyclin D1 (ab16663, 1:1000), Bcl-2 (ab32124, 1:1000), Bax (ab32124, 1:1000), cleaved Caspase-3 (ab4051, 1:1000), N-cadherin (ab18203, 1:1000), vimentin (ab137321, 1:1000), E-cadherin (ab15148, 1:1000), TMSB4X (ab167650, 1:1000), or TGF-β2 (ab113670, 1:1000) at 4°C overnight and incubated with corresponding HRP-conjugated secondary antibodies (ab131368 and ab191866; both 1:5,000) for 2 h at room temperature. Eventually, the proteins were visualized via ECL (Thermo Pierce), with GAPDH as the loading control.
Bioinformatics analysis
StarBase website (http://starbase.sysu.edu.cn ) was used to find candidate microRNAs (miRNAs) for circPIP5K1A, and miRmap (https://mirmap.ezlab.org ), PITA (http://genie.weizmann.ac.il/pubs/mir07/mir07_data.html ), and PicTar (http://www.pictar.mdc-berlin.de ) databases were used to predict the candidate target genes for miR-153-3p.
Bioinformatics analysis
StarBase website (