Restoration of RUNX3 enhances transforming growth factor-β-dependent p21 expression in a biliary tract cancer cell line
Authors: Hasegawa, Kazunori1; Yazumi, Shujiro1; Wada, Manabu1; Sakurai, Toshiharu1; Kida, Masaya1; Yamauchi, Junichi1; Hisatsune, Hiroshi1; Tada, Shinsuke1; Ida, Hiroshi1; Nakase, Yuenn2; Sakakura, Chohei2; Hagiwara, Akeo2; Chiba, Tsutomu
Source: Cancer Science, Volume 98, Number 6, June 2007 , pp. 838-843(6)
Publisher: Blackwell Publishing
Abstract:
RUNX3 is a candidate tumor suppressor gene localized in 1p36, a region commonly inactivated by deletion and methylation in various human tumors. To elucidate the role of RUNX3 in transforming growth factor (TGF)-β signaling in biliary tract cancer, we transfected Mz-ChA-2 cells, which do not express RUNX3 but have intact TGF-β type II receptor and SMAD4 genes, with the RUNX3 expression plasmid pcDNA3.1/RUNX3 or with the vector pcDNA3.1 as a control. Four Mz-ChA-2/RUNX3 clones and one control clone were obtained. Although TGF-β1 only slightly inhibited growth of the control cells, growth inhibition and TGF-β-dependent G1 arrest were significantly enhanced in the RUNX3-transfected clones. None of the clones, however, exhibited apoptosis. The slightly increased TGF-β1-induced p21 expression in the control clone was strongly enhanced in the RUNX3-transfected clones, and was accompanied by augmented decreases in the expression of cyclins D1 and E. When RUNX3 small interfering RNA was added, TGF-β-dependent induction of p21 was reduced in the RUNX3-transfected clones. Xenografts of the clones in nude mice demonstrated that tumorigenicity was significantly decreased in the RUNX3-transfected clones in inverse proportion to the expression levels of RUNX3. Based on these results, RUNX3 is involved in TGF-β-induced expression of p21 and the resulting induction of TGF-β-dependent G1 arrest. (Cancer Sci 2007; 98: 838-843)Document Type: Research article
DOI: 10.1111/j.1349-7006.2007.00460.x
Affiliations: 1: Department of Gastroenterology and Hepatology, Kyoto University Graduate School of Medicine, Kyoto, 606-8507; 2: Department of Digestive Surgery, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan

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