title: Quantitative proteomic analysis of HepG2 cells treated with quercetin suggests IQGAP1 involved in quercetin-induced regulation of cell proliferation and migration.
abstract: Quercetin, a wild distributed bioflavonoid, exhibits antitumor effects on murine models by inducing apoptosis and inhibiting growth of many cancer cell lines, while proteins involved in antitumor effects at proteomic level are still unclear. In our study, we used a quantitative proteomic strategy termed stable isotope labeling by amino acids in cell culture (SILAC)-mass spectrometry (MS) to study the differential proteomic profiling of HepG2 cells treated by quercetin. In all, there were 70 changed proteins among those quantified proteins in HepG2 cells treated by 50 microM quercetin for 48 h, and 14 proteins showed significant upregulation, whereas 56 proteins were downregulated. The functional classification of changed proteins includes signaling protein, protein synthesis, cytoskeleton, metabolism, etc. Of these, Ras GTPase-activating-like protein (IQGAP1) and beta-tubulin were found to be reduced at a large degree. The migration inhibition of HepG2 cells can be induced by quercetin, and the RNA and protein expression level of IQGAP1 and beta-tubulin were respectively decreased obviously in HepG2 cells exposed to quercetin for 48 h in the scratch migration assay. The downregulated expression of IQGAP1 and beta-tubulin by quercetin treatment correlated with cell migration ability, and quercetin probably inhibits HepG2 proliferation and migration through IQGAP1 and beta-tubulin expression changes and their interactions with other proteins.
authors.affiliation: State Key Laboratory of Biotherapy and Cancer Centre, West China Hospital, West China Medical School, Sichuan University, #1 Keyuan Street 4, Gaopeng Street, Chengdu, People's Republic of China.
authors.forename: Jin
authors.initials: J
authors.lastname: Zhou
authors.forename: Shufang
authors.initials: S
authors.lastname: Liang
authors.forename: Li
authors.initials: L
authors.lastname: Fang
authors.forename: Lijuan
authors.initials: L
authors.lastname: Chen
authors.forename: Minghai
authors.initials: M
authors.lastname: Tang
authors.forename: Yuhuan
authors.initials: Y
authors.lastname: Xu
authors.forename: Afu
authors.initials: A
authors.lastname: Fu
authors.forename: Jinliang
authors.initials: J
authors.lastname: Yang
authors.forename: Yuquan
authors.initials: Y
authors.lastname: Wei
mesh_terms: D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects*; D049109:Cell Proliferation / Q000187:drug effects*; D002853:Chromatography, Liquid; D006801:Humans; D040901:Proteomics; D011794:Quercetin / Q000494:pharmacology*; D053719:Tandem Mass Spectrometry; D020703:ras GTPase-Activating Proteins / Q000502:physiology*
chemical_list: C101203:IQ motif containing GTPase activating protein 1; D020703:ras GTPase-Activating Proteins; D011794:Quercetin