title: Down-regulation of Smad4 enhances proliferation and invasion of colorectal             carcinoma HCT116 cells and up-regulates Id2.
abstract: The aim of this study was to determine whether the suppression of Smad4             by short hairpin RNA (shRNA) regulates the proliferation and invasion of colorectal             carcinoma HCT116 cells and Id2 expression. The Smad4‑shRNA expression vectors             were constructed and stably transfected to HCT116 cells. The expression of mRNA             and protein of Smad4 and Id2 was detected using reverse transcription-polymerase             chain reaction (RT-PCR) and Western blotting. Cellular proliferation inhibitory             activity was determined by methyl thiazolyl tetrazolium (MTT) assay. Transwell             assay was used to detect the effect of the inhibition of Smad4-shRNA on migration             and invasion. The Smad4-shRNA vector, which inhibited Smad4 expression, was constructed             and successfully transfected to HCT116 cells. The levels of mRNA and protein expression             of Smad4 were markedly decreased following transfection of shRNA compared with             the control groups (P<0.05). The abilities of proliferation, migration and             invasion were increased following transfection of shRNA (P<0.05). The expression             of Id2 was increased following transfection of shRNA (P<0.05). For the Smad4-down-regulated             HCT116 cells, treated with or without BMP7 (25 ng/ml), no difference was found.             shRNA-mediated silencing of Smad4 was able to enhance the abilities of proliferation,             migration and invasion in the HCT116 cell line. Therefore, Smad4 may act as a             tumor-suppressor gene in colorectal carcinoma.
authors.affiliation: Endoscopic Center, Zhongshan Hospital, Fudan University, Shanghai 200032, PR China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Shi
authors.forename: Yun-Shi
authors.initials: YS
authors.lastname: Zhong
authors.forename: Li-Qing
authors.initials: LQ
authors.lastname: Yao
authors.forename: Quan-Lin
authors.initials: QL
authors.lastname: Li
authors.forename: Zhong
authors.initials: Z
authors.lastname: Ren
authors.forename: Xiang-Ping
authors.initials: XP
authors.lastname: Liu
authors.forename: Fa-Mao
authors.initials: FM
authors.lastname: Shi
mesh_terms: D055419:Bone Morphogenetic Protein 7 / Q000378:metabolism; D002465:Cell Movement; D049109:Cell Proliferation; D015179:Colorectal Neoplasms / Q000378:metabolism* / Q000473:pathology; D015536:Down-Regulation; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D045325:HCT116 Cells; D006801:Humans; D051797:Inhibitor of Differentiation Protein 2 / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D012333:RNA, Messenger / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism / Q000494:pharmacology*; D051901:Smad4 Protein / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D015854:Up-Regulation
chemical_list: D055419:Bone Morphogenetic Protein 7; C497450:ID2 protein, human; D051797:Inhibitor of Differentiation Protein 2; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D051901:Smad4 Protein