Effects of SIRT6 Gene Silencing on Human Hepatocellular Carcinoma Cell Proliferation and Apoptosis in Ectopic Xenograft Nude Mouse Model

Abstract: This study investigated the effects of SIRT6 gene silencing on human hepatocellular carcinoma cell proliferation and apoptosis in ectopic xenograft nude mouse model. SIRT6-shRNA-SK-Hep-1 and shCont-SKHep-1 stable cell lines were established. The mRNA and protein levels of SIRT6 gene were measured by quantitative reverse transcription polymerase chain reaction (qRT-PCR) and Western blot， respectively. The stable cell lines were injected into the subcutaneous of nude mouse and the growth of ectopic xenograft nude mouse were monitored at regular intervals. The ectopic xenograft nude mouse were stripped out and weighted after injection for 7 weeks. The protein levels of SIRT6， Ki-67 were detected by immunohistochemical staining. Then， effects of SIRT6 gene silencing on downstream target molecules inhibitor of apoptosis proteins (IAPs) family were determined by qRT-PCR. The protein level of X-linked inhibitor of apoptosis protein gene (XIAP) and poly ADP-ribose polymerase (PARP) were determined by Western blot. Our results showed that SIRT6-depleted SK-Hep-1 stable cell lines were established successfully. Both the size and weight of ectopic xenograft nude mouse were lower in SIRT6-shRNA-SK-Hep-1 group than that in shCont-SK-Hep-1 group (P<0.01). The protein level of Ki-67 was down-regulated in SIRT6-shRNA-SK-Hep-1 group detected by immunohistochemical staining. Knockdown of SIRT6 gene down-regulated the mRNA and protein levels of XIAP， and raised the protein cleavage of PARP. These data indicated that SIRT6 gene silencing might inhibit human hepatocellular carcinoma cell proliferation and apoptosis in ectopic xenograft nude mouse model by down-regulating XIAP protein level.

CSTR: 32200.14.cjcb.2016.07.0008