title: Expression of p66(Shc) protein correlates with proliferation of human prostate cancer cells.
abstract: p66(Shc), an isoform of Shc adaptor proteins, is shown to mediate various signals, including cellular stress. However, little is known about its involvement in carcinogenesis. We previously showed that p66(Shc) protein level is upregulated by steroid hormones in human carcinoma cells and is higher in prostate cancer (PCa) specimens than adjacent noncancerous cells. In this study, we investigated the role of p66(Shc) protein in PCa cell proliferation. Among different PCa cell lines tested, p66(Shc) protein level showed positive correlation with cell proliferation, that is, rapid-growing cells expressed higher p66(Shc) protein than slow-growing cells. Exposure of slow-growing LNCaP C-33 cells to epidermal growth factor (EGF) and 5alpha-dihydrotestosterone (DHT) led to upregulation of proliferation and p66(Shc) protein level. Conversely, growth suppression of fast-growing cells by cellular form of prostatic acid phosphatase (cPAcP) expression, a negative growth regulator, down-regulated their p66(Shc) protein level. Additionally, increased expression of p66(Shc) protein by cDNA transfection in LNCaP C-33 cells resulted in increased cell proliferation. Cell cycle analyses showed higher percentage of p66(Shc)-overexpressing cells at S phase (24%) than control cells (17%), correlating with their growth rates. On the other hand, transient knock-down of p66(Shc) expression by RNAi in rapidly growing cells decreased their proliferation as evidenced by the reduced cell growth as well as S phase in p66(Shc)-knocked down cells. The p66(Shc) signaling in cell growth regulation is apparently mediated by extracellular signal-regulated kinase/mitogen-activated protein kinase (ERK/MAPK). Thus, our results indicate a novel role for p66(Shc) in prostate carcinogenesis, in part, promoting cell proliferation.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, 985870 Nebraska Medical Center, Omaha, NE 68198, USA.
authors.forename: Suresh
authors.initials: S
authors.lastname: Veeramani
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Igawa
authors.forename: Ta-Chun
authors.initials: TC
authors.lastname: Yuan
authors.forename: Fen-Fen
authors.initials: FF
authors.lastname: Lin
authors.forename: Ming-Shyue
authors.initials: MS
authors.lastname: Lee
authors.forename: Jamie S
authors.initials: JS
authors.lastname: Lin
authors.forename: Sonny L
authors.initials: SL
authors.lastname: Johansson
authors.forename: Ming-Fong
authors.initials: MF
authors.lastname: Lin
mesh_terms: D000135:Acid Phosphatase; D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D002999:Clone Cells; D013196:Dihydrotestosterone / Q000494:pharmacology; D004815:Epidermal Growth Factor / Q000494:pharmacology; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects*; D006801:Humans; D008297:Male; D010766:Phosphorylation; D011471:Prostatic Neoplasms / Q000378:metabolism* / Q000473:pathology; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D017027:Protein Tyrosine Phosphatases / Q000494:pharmacology; D034622:RNA Interference; D016196:S Phase; D055765:Shc Signaling Adaptor Proteins; D015398:Signal Transduction; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D020033:Protein Isoforms; C528024:SHC1 protein, human; D055765:Shc Signaling Adaptor Proteins; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; D013196:Dihydrotestosterone; D004815:Epidermal Growth Factor; D048049:Extracellular Signal-Regulated MAP Kinases; D000135:Acid Phosphatase; C428439:prostatic acid phosphatase; D017027:Protein Tyrosine Phosphatases