OBJECTIVETo investigate the impact of aquaporin 9 (AQP9) on the proliferation,apoptosis,invasiveness and migration of hepatocellular carcinoma cells using the HepG2 cell line.

METHODSA lentiviral vector targeting the coding region of human AQP9 was constructed. The recombinant lentiviral vector was harvested from the 293T cell line and transfected into the HepG2 cell line; resistant cell clones were selected with puromycin. Three groups of cells were established, including the CC group (control without lentiviral vector), the PWPI group (control with empty carrier virus), and the AQP9 overexpression group (experimental with the AQP9 recombinant virus). Transfection efficiency was validated by laser confocal microscopy.Expression of AQP9 was detected in the transfected HepG2 cells by westem blotting (protein) and real-time qPCR (mRNA). AQP9 effects on proliferation, migration, invasion and apoptosis of the HepG2 cell line were assessed by plate colony formation assay, woumd healing assay, transwell assay and flow cytometry.

RESULTSThe green fluorescent protein of the recombinant lentiviral vector was appropriately distributed in the cell membrane. The AQP9 overexpression group showed significantly higher AQP9 mRNA and protein levels than the PWPI group and the CC group (both P < 0.01). Cells with AQP9 overexpression showed a lower colony formation rate (16.93±3.19% vs. CC group: 23.53±2.10% and PWPI group: 23.00±2.02%; F=6.46, P=0.032) and a lower overall apoptosis rate (44.96±3.53% vs. CC group:19.7±2.49% and PWPI group: 24.37±2.38%; F=66.88, P < 0.01). The AQP9 overexpression group also showed significantly higher number of cells in the G1 stage and significantly lower number of cells in the S stage (G1: 66.58±0.99% and S:15.25±1.81%), significantly smaller cell migration distance (P=0.01 < 0.05), and significantly suppressed invasiveness (17±8 vs. CC group:109+/-9 and PWPI group: 95±11; P=0.01 < 0.05).

CONCLUSIONIn HepG2 cells, AQP9 significantly reduces the migrative and invasive capabilities, induces cell apoptosis, and inhibits cell proliferation via cell cycle arrest at the G1/S phases.