title: Reduced ubiquitin-specific protease 9X expression induced by RNA interference inhibits the bioactivity of hepatocellular carcinoma cells.
abstract: Ubiquitin-specific protease 9X (USP9X) is crucial in many tumor types, but not in hepatocellular carcinoma (HCC). The current study aimed to examine the effects of RNA interference on USP9X expression, and subsequently on the bioactivity of HCC SMMC7721 and HepG2 cells. The protein expression of USP9X in SMMC7721, HepG2 and normal human liver cell line L02 at the cellular level was determined by western blot analysis; USP9X was knocked down by small interfering RNA (siRNA) in HCC SMMC7721 and HepG2 cells.In vitrocell viability was assessed by MTT assay, apoptosis was determined by flow cytometry (FCM) and cell migration was evaluated by Transwell assays. The protein expression of USP9X in SMMC7721 and HepG2 were both significantly higher than that in L02 (P<0.01). The results of western blot demonstrated that the USP9X-siRNA could efficiently inhibit USP9X expression when compared with that of the negative control (NC) group (P<0.01) and MTT assay demonstrated that cell proliferation in USP9X-blocked cells was significantly reduced when compared with that of the NC group (P<0.01). The results of FCM revealed that apoptosis was significantly increased in USP9X-blocked cells when compared with that of the NC group (P<0.01). The results of transwell assay showed that cell migration was significantly inhibited in USP9X-blocked cells when compared with that of the NC group (P<0.01). These results show that expression of USP9X is upregulated in hepatoma cells SMMC7721 and HepG2, and that downregulating USP9X by siRNA may induce cell apoptosis, inhibit cell growth and cell migration in the HCC SMMC7721 and HepG2 cell lines. USP9X may therefore be a potential target for HCC treatment and early detection.
authors.affiliation: Department of Hepatobiliary Surgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, P.R. China.
authors.forename: Huiwen
authors.initials: H
authors.lastname: Hu
authors.affiliation: Department of Clinical Pharmacology, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, P.R. China.
authors.forename: Chengyong
authors.initials: C
authors.lastname: Tang
authors.affiliation: Department of Hepatobiliary Surgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, P.R. China.
authors.forename: Qinghu
authors.initials: Q
authors.lastname: Jiang
authors.affiliation: Department of Hepatobiliary Surgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, P.R. China.
authors.forename: Wei
authors.initials: W
authors.lastname: Luo
authors.affiliation: Department of Hepatobiliary Surgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, P.R. China.
authors.forename: Jiming
authors.initials: J
authors.lastname: Liu
authors.affiliation: Department of Hepatobiliary Surgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, P.R. China.
authors.forename: Xufu
authors.initials: X
authors.lastname: Wei
authors.affiliation: Department of Hepatobiliary Surgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, P.R. China.
authors.forename: Rui
authors.initials: R
authors.lastname: Liu
authors.affiliation: Department of Hepatobiliary Surgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, P.R. China.
authors.forename: Zhongjun
authors.initials: Z
authors.lastname: Wu
keywords: RNA interference; apoptosis; growth; hepatocellular carcinoma; migration; ubiquitin-specific protease 9X