The retinoblastoma tumor suppressor modifies the therapeutic response of breast cancer

Bosco, E. E., Wang, Y., Xu, H., Zilfou, J. T., Knudsen, K. E., Aronow, B. J., Lowe, S. W., Knudsen, E. S. (January 2007) The retinoblastoma tumor suppressor modifies the therapeutic response of breast cancer. J Clin Invest, 117 (1). pp. 218-228. ISSN 0021-9738 (Print)

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DOI: 10.1172/jci28803


The retinoblastoma tumor suppressor (RB) protein is functionally inactivated in the majority of human cancers and is aberrant in one-third of all breast cancers. RB regulates G(1)/S-phase cell-cycle progression and is a critical mediator of antiproliferative signaling. Here the specific impact of RB deficiency on E2F-regulated gene expression, tumorigenic proliferation, and the response to 2 distinct lines of therapy was investigated in breast cancer cells. RB knockdown resulted in RB/E2F target gene deregulation and accelerated tumorigenic proliferation, thereby demonstrating that even in the context of a complex tumor cell genome, RB status exerts significant control over proliferation. Furthermore, the RB deficiency compromised the short-term cell-cycle inhibition following cisplatin, ionizing radiation, and antiestrogen therapy. In the context of DNA-damaging agents, this bypass resulted in increased sensitivity to these agents in cell culture and xenograft models. In contrast, the bypass of antiestrogen signaling resulted in continued proliferation and xenograft tumor growth in the presence of tamoxifen. These effects of aberrations in RB function were recapitulated by ectopic E2F expression, indicating that control of downstream target genes was an important determinant of the observed responses. Specific analyses of an RB gene expression signature in 60 human patients indicated that deregulation of this pathway was associated with early recurrence following tamoxifen monotherapy. Thus, because the RB pathway is a critical determinant of tumorigenic proliferation and differential therapeutic response, it may represent a critical basis for directing therapy in the treatment of breast cancer.

Item Type: Paper
Subjects: diseases & disorders > cancer
diseases & disorders > cancer > cancer types > breast cancer
diseases & disorders > cancer > cancer types > retinoblastoma
CSHL Authors:
Communities: CSHL labs > Lowe lab
Depositing User: CSHL Librarian
Date: 2 January 2007
Date Deposited: 01 Dec 2011 21:11
Last Modified: 22 Mar 2018 14:53
PMCID: PMC1679964
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