title: Suppression of N-Ras by shRNA-expressing plasmid increases sensitivity of HepG2 cells to vincristine-induced growth inhibition.
abstract: Oncogenic ras genes relate to the development of human cancers. In this study, we used a plasmid-mediated short-hairpin RNA (shRNA) targeting N-ras gene to combine with clinical drug vincristine (VCR) for the treatment of human hepatoma cells. Our results showed that anti-N-Ras shRNA expression vector (pCSH1-shNR) knocked down the target mRNA and protein. Higher efficacy on growth inhibition was observed when pCSH1-shNR was combined with VCR. This synergistic effect was associated with abrogation of VCR-induced overexpressions of P-glycoprotein and multidrug resistance-associated protein 1 by pCSH1-shNR through downregulations of N-Ras and total Ras. Western blot analysis showed that pCSH1-shNR-induced downregulations of N-Ras and total Ras were potentiated by VCR. Following Ras downregulation, phosphorylations of ERK1/2 and Akt were dramatically inhibited by combinatory treatment. The data showed that pCSH1-shNR-induced inhibition of nuclear factor-kappaB was enhanced by VCR. In addition, the combination of pCSH1-shNR and VCR synergistically inhibited the growth of human hepatoma HepG2 in vivo. Our findings suggested that combination of gene-specific therapeutics and appropriate chemotherapeutic agents might be a promising approach for the treatment of human hepatocellular carcinoma.
authors.affiliation: Department of Oncology, Institute of Medicinal Biotechnology, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100050, China.
authors.forename: H-x
authors.initials: HX
authors.lastname: Sun
authors.forename: H-w
authors.initials: HW
authors.lastname: He
authors.forename: S-h
authors.initials: SH
authors.lastname: Zhang
authors.forename: T-g
authors.initials: TG
authors.lastname: Liu
authors.forename: K-h
authors.initials: KH
authors.lastname: Ren
authors.forename: Q-y
authors.initials: QY
authors.lastname: He
authors.forename: R-g
authors.initials: RG
authors.lastname: Shao
mesh_terms: D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology / Q000627:therapeutic use*; D006528:Carcinoma, Hepatocellular / Q000235:genetics / Q000473:pathology / Q000628:therapy*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects*; D003131:Combined Modality Therapy; D015536:Down-Regulation; D005260:Female; D015870:Gene Expression; D011905:Genes, ras / Q000235:genetics*; D015316:Genetic Therapy; D006801:Humans; D008113:Liver Neoplasms / Q000235:genetics / Q000473:pathology / Q000628:therapy*; D020935:MAP Kinase Signaling System; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D010957:Plasmids; D034622:RNA Interference; D014750:Vincristine / Q000494:pharmacology / Q000627:therapeutic use*; D023041:Xenograft Model Antitumor Assays
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D014750:Vincristine