Inhibiting effect of AQP9 over-expression on the growth of hepatoma carcinoma SMMC-7721 cells subcutaneously transplanted in nude mice and its possible mechanism / 肿瘤

ABSTRACT

Objective: To investigate the effect of aquaporin 9 (AQP9) on the growth of human hepatoma carcinoma SMMC-7721 cells in nude mice and its possible mechanism. Methods: SMMC-7721 cells were infected with recombinant lentivirus LV-AQP9 (empty lentivirus LV-CFP as a negative control). The infection efficiency of recombinant lentivirus LV-AQP9 in SMMC-7721 cells was observed under a laser scanning confocal microscope, and the expression levels of AQP9 mRNA and protein were detected by real-time fluorescence-based quantitative PCR and Western blotting, respectively. The apoptosis of SMMC-7721 cells was analyzed by FCM and 4, 6-diamidino-2-phenylindole (DAPI) staining, respectively. The proliferation ability of SMMC-7721 cells was analyzed by cell counting kit-8 (CCK-8). Recombinant hepatoma carcinoma SMMC-7721/LV-AQP9 (AQP9 group) and SMMC-7721/LVCFP cells (CFP group) were subcutaneously implanted in nude mice. The volume and growth rate of the xenograft tumors were observed. Pathological alteration in xenograft tumors and lung tissues were observed by HE-staining. The expression level of proliferating cell nuclear antigen (PCNA) protein was detected by immunohistochemical staining. Results: The infection efficiency of recombinant lentivirus LV-AQP9 in SMMC-7721 cells was about 90% under a laser scanning confocal microscope. The AQP9 mRNA and protein expression levels in SMMC-7721 cells were significantly increased (both P < 0.01). AQP9 over-expression could significantly promote the apoptosis of SMMC-7721 cells (P < 0.05), and significantly inhibit the proliferation of SMMC-7721 cells at different time points (48-96 h) after transfection (all P < 0.05). The results of ANOVA for repeated measurement of xenograft tumor volume displayed that xenograft tumor volume of AQP9 over-expression group was smaller than that of CFP group, and the growth rate was slower (Fgroup = 79.161, Pgroup = 0.000; Ftime = 101.965, Ptime, = 0.000; Fgroupxtime = 18.481, Fgroupxtime = 0.002). Immunohistochemistry staining showed that the expression level of PCNA protein in the xenograft tumor of over-expression group significantly decreased compared with that of the control group. Conclusion: AQP9 over-expression can inhibit the growth of xenografts of human hepatoma carcinoma SMMC-7721 cells in nude mice and possibly conduct dual control by promoting apoptosis and inhibiting the proliferation, which provides the foundation for further research on molecular mechanism, and it is expected to become a new target for cancer treatment.