ABSTRACT
@#[Abstract] Objective: To explore the effect of CAAP1 on apoptosis, proliferation, migration and invasion of hepatocellular carcinoma (HCC) HepG2 cells and its mechanism. Methods: The pcDNA3/CAAP1 (CAAP1 over-expression) and pSilencer 2.1-U6 neo/shR-CAAP1 (CAAP1 knockdown) plasmids were constructed and transfected into HepG2 cells. The mRNA and protein levels of CAAP1 were detected by qPCR and WB, respectively. The cells were divided into four groups, namely overexpression control group (pcDNA3), CAAP1 over-expression group (pcDNA3/CAAP1), silence control group (pSilencer 2.1-U6 neo, pSilencer) and CAAP1 silence group (pSilencer 2.1-U6 neo/shR-CAAP1, shR-CAAP1). Flow cytometry was used to analyze the apoptosis, and WB was used to detect the protein expression of cleaved caspase 3 in each group. CCK-8 assay was used to detect the proliferation of HepG2 cells, Colony formation assay was used to detect the clonogenesis, and Transwell assay and wound healing assay were used to detect the invasion and migration abilities of HepG2 cells in each group. The effect of CAAP1 on overall survival (OS) of HCC patients was analyzed after searching TCGA database. Results: PcDNA3/CAAP1 with CAAP1 over-expression and shR-CAAP1 with CAAP1 knockdown were successfully constructed. It was confirmed that pcDNA3/CAAP1 could increase the mRNA and protein expressions of CAAP1, while shR-CAAP1 could decrease the mRNA and protein expressions of CAAP1 (all P<0.05). The cell apoptotic rate in pcDNA3/CAAP1 group decreased by 32% as compared to pcDNA3 group, and the cleaved caspase 3 protein expression was significantly decreased (all P<0.05); while the cell apoptotic rate in shR-CAAP1 group increased by 73% as compared to pSilencer group, and the cleaved caspase 3 protein expression was significantly increased (all P<0.05). The cell proliferation in pcDNA3/CAAP1 group significantly increased (P<0.05), while the cell proliferation in shR-CAAP1 group significantly decreased (P<0.05). The cell migration number increased by 48%, the cell migration distance increased by 59% (P<0.05) and the cell invasion number increased by 52% in pcDNA3/CAAP1 group (all P<0.05). The cell migration number decreased by 53%, cell migration distance decreased by 29% and cell invasion number decreased by 45% in shR-CAAP1 group (all P<0.05). TCGA database analysis showed that the high expression of CAAP1 was negatively correlated with the OS of HCC patients (P<0.05). Conclusion: CAAP1 can promote the proliferation, migration and invasion of HepG2 cells by inhibiting its apoptosis, and it may be closely related to the occurrence and development of HCC.