Differential expression of antiapoptotic gene BAG-1 in human breast normal and cancer cell lines and tissues

Xiaolong Yang, Yawei Hao, Zhihu Ding, Alan Pater, Shou Ching Tang

Research output: Contribution to journalArticle

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Abstract

BAG-1 is an antiapoptotic protein that binds to and enhances the antiapoptotic activity of Bcl-2. It binds several growth factor and hormone receptors and modulates their function. BAG-1 was also shown recently to be expressed as four protein isoforms, p50, p46, p33, and p29, through alternative translation initiation. Although many apoptosis-associated genes have been linked to oncogenesis of human breast cancer, the role of BAG-1 has not been fully elucidated. In this study, we examined the expression of BAG- 1 RNA or protein isoforms and its interacting antiapoptotic proteins, Bcl-2 and Bcl-X(L), in breast normal and tumor cell lines and tissues by Northern or Western blot analysis. We provide convincing evidence that both BAG-1 RNA and protein are overexpressed in human breast cancer cell lines. More importantly, we found that the expression of two isoforms of BAG-1, p46 and p33, was also much higher in breast primary tumors. The expression of Bcl-2 and Bcl-X(L) correlated with that of BAG-1 in breast normal and carcinoma cell lines but not tissues. Our study suggests that BAG-1 isoforms may serve as a molecular marker, independent of Bcl-2 and Bcl-X(L), for human breast cancer.

Original languageEnglish (US)
Pages (from-to)1816-1822
Number of pages7
JournalClinical Cancer Research
Volume5
Issue number7
StatePublished - Jul 1 1999

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ASJC Scopus subject areas

  • Oncology
  • Cancer Research

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