Profiling of gene expression changes caused by p53 gain-of-function mutant alleles in prostate cancer cells

Clifford G. Tepper, Jeffrey P. Gregg, Xu Bao Shi, Ruth L. Vinall, Colin A. Baron, Philip E. Ryan, Pierre Yves Desprez, Hsing Jien Kung, Ralph W. DeVere White

Research output: Contribution to journalArticle

29 Citations (Scopus)

Abstract

BACKGROUND. Tumor suppressor p53 mutations are associated with the transition of prostate cancer to metastatic, hormone-refractory disease and stable expression of p53 gain-of-function (p53GOF) alleles support growth of LNCaP in androgen-depleted medium. In this study, we performed gene expression profiling of four LNCaP-p53GOF sublines to test the hypothesis that different p53GOF mutants mediated androgen independence via modulation of a common set of genes. METHODS. Expression profiling was performed using Affymetrix HG-U95Av2 arrays followed by hierarchical clustering to identify expression patterns associated with particular molecular alterations. p53GOF-mediated regulation of Id-1 expression was validated by RT-PCR and dual-lUCiferase reporter assays. RNA interference was used to investigate the effects of Id-1 and Id-3 suppression. RESULTS. LNCaP-p53GOF sublines possessed a molecular signature consisting of 95 differentially regulated genes that could be segregated into two clusters of transcripts indUCed (n = 50) and repressed (n = 45) by p53 GOF expression. To begin validating these genes as effectors of the p53 mutants, we evaluated one of the overexpressed genes, Id-1. RT-PCR confirmed the microarray results and revealed elevated Id-1 levels in LNCaP-p53-P151S (loss-of-function only mutant), thereby implicating p53 mutational inactivation, but not gain-of-function, as a basis for Id-1 deregulation. Reporter assays demonstrated enhanced Id-1 promoter activity in an LNCaP-p53GOF subline. The contribution of Id-1 to p53GOF-mediated biology was demonstrated by the ability of RNAi-mediated gene silencing to decrease both basal and androgen-independent proliferation. CONCLUSIONS. While different p53GOF mutants result in overall distinct expression profiles, they share a common set of differentially-expressed genes that can be used to signify their presence and provide insight into mechanisms underlying androgen independence.

Original languageEnglish
Pages (from-to)375-389
Number of pages15
JournalProstate
Volume65
Issue number4
DOIs
Publication statusPublished - Dec 1 2005
Externally publishedYes

Keywords

  • Androgen independence
  • Id-1
  • Microarray
  • RNA interference

ASJC Scopus subject areas

  • Oncology
  • Urology

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  • Cite this

    Tepper, C. G., Gregg, J. P., Shi, X. B., Vinall, R. L., Baron, C. A., Ryan, P. E., Desprez, P. Y., Kung, H. J., & DeVere White, R. W. (2005). Profiling of gene expression changes caused by p53 gain-of-function mutant alleles in prostate cancer cells. Prostate, 65(4), 375-389. https://doi.org/10.1002/pros.20308