Knockdown of SYT13 induces cell apoptosis. (A) Flow cytometry analysis was employed to detect the percentage of apoptotic cells among RKO and HCT116 cells with SYT13 knockdown compared with the negative control. Data are presented as the mean ± standard deviation (n≥3). **P<0.01. SYT, synaptotagmin. Knockdown of SYT13 induces cell apoptosis. (B) Cell cycle analysis of RKO and HCT116 cells with SYT13 knockdown and the negative control, and the percentage of cells in the G1, S and G2 phase of the cell cycle. (C) The expression levels of several apoptosis-related proteins, including Bad, Bcl-2, P53 and survivin, were detected by western blot analysis. Data are presented as the mean ± standard deviation (n≥3). *P<0.05, **P<0.01, ***P<0.001. SYT, synaptotagmin.