Different expression patterns of Bcl-2 family genes in breast cancer by estrogen receptor status with special reference to pro-apoptotic Bak gene

H. Eguchi, K. Suga, H. Saji, M. Toi, K. Nakachi, S. I. Hayashi

Research output: Contribution to journalArticlepeer-review

29 Citations (Scopus)

Abstract

Oncogenic and anti-apoptotic Bcl-2 is expressed much less in estrogen receptor α (ERα) negative breast cancers, which show more malignant phenotypes, than ERα-positive, indicating that some other Bcl-2 family member(s) are involved in the apoptotic balance of the cancer cells. We first analyzed mRNA expression of pro-apoptotic Bak and Bax along with that of anti-apoptotic Bcl-2 and Bcl-x(L), using breast cancer specimens of 27 patients. Bak mRNA was expressed much less in ERα negative breast cancers, along with reduced expression of Bcl-2. Immunostaining of sections of 108 patients confirmed the observation. Next, stable transformants of MCF-7 cells with sense Bak expression vector showed fewer colonies in soft agar compared with the parental cells, while stable introduction of antisense Bak vector enhanced colony formation at lower estradiol concentrations. The reduction of Bak may play important roles in malignant development of breast cancer to acquire estrogen independency, counteracting the reduced Bcl-2.

Original languageEnglish
Pages (from-to)439-446
Number of pages8
JournalCell Death and Differentiation
Volume7
Issue number5
DOIs
Publication statusPublished - 2000 May
Externally publishedYes

Keywords

  • Apoptosis
  • Bak
  • Breast cancer
  • Estrogen receptor

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology

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