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Title: AIB1 is required for the acquisition of epithelial growth factor receptor-mediated tamoxifen resistance in breast cancer cells

Journal Article · · Biochemical and Biophysical Research Communications
 [1]; ; ;  [1]
  1. Department of Medical Oncology, Tumor Hospital of Harbin Medical University, Harbin 150040 (China)

Acquired resistance to tamoxifen has become a serious obstacle in breast cancer treatment. The underlying mechanism responsible for this condition has not been completely elucidated. In this study, a tamoxifen-resistant (Tam-R) MCF-7 breast cancer cell line was developed to mimic the occurrence of acquired tamoxifen resistance as seen in clinical practice. Increased expression levels of HER1, HER2 and the estrogen receptor (ER)-AIB1 complex were found in tamoxifen-resistant cells. EGF stimulation and gefitinib inhibition experiments further demonstrated that HER1/HER2 signaling and AIB1 were involved in the proliferation of cells that had acquired Tam resistance. However, when AIB1 was silenced with AIB1-siRNA in Tam-R cells, the cell growth stimulated by the HER1/HER2 signaling pathway was significantly reduced, and the cells were again found to be inhibited by tamoxifen. These results suggest that the AIB1 protein could be a limiting factor in the HER1/HER2-mediated hormone-independent growth of Tam-R cells. Thus, AIB1 may be a new therapeutic target, and the removal of AIB1 may decrease the crosstalk between ER and the HER1/HER2 pathway, resulting in the restoration of tamoxifen sensitivity in tamoxifen-resistant cells.

OSTI ID:
21255935
Journal Information:
Biochemical and Biophysical Research Communications, Vol. 380, Issue 3; Other Information: DOI: 10.1016/j.bbrc.2009.01.155; PII: S0006-291X(09)00215-0; Copyright (c) 2009 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0006-291X
Country of Publication:
United States
Language:
English