GGNBP2 acts as a tumor suppressor by inhibiting estrogen receptor α activity in breast cancer cells


Gametogenetin-binding protein 2 (GGNBP2) is encoded in human chromosome 17q12-q23, a region known as a breast and ovarian cancer susceptibility locus. GGNBP2, also referred to ZFP403, has a single C2H2 zinc finger and a consensus LxxLL nuclear receptor-binding motif. Here, we demonstrate that GGNBP2 expression is reduced in primary human breast tumors and in breast cancer cell lines, including T47D, MCF-7, LCC9, LY2, and MDA-MB-231 compared with normal, immortalized estrogen receptor α (ERα) negative MCF-10A and MCF10F breast epithelial cells. Overexpression of GGNBP2 inhibits the proliferation of T47D and MCF-7 ERα positive breast cancer cells without affecting MCF-10A and MCF10F. Stable GGNBP2 overexpression in T47D cells inhibits 17β-estradiol (E2)-stimulated proliferation as well as migration, invasion, anchorage-independent growth in vitro, and xenograft tumor growth in mice. We further demonstrate that GGNBP2 protein physically interacts with ERα, inhibits E2-induced activation of estrogen response element-driven reporter activity, and attenuates ER target gene expression in T47D cells. In summary, our in vitro and in vivo findings suggest that GGNBP2 is a novel breast cancer tumor suppressor functioning as a nuclear receptor corepressor to inhibit ERα activity and tumorigenesis.

DOI: 10.1007/s10549-016-3880-2

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@article{Lan2016GGNBP2AA, title={GGNBP2 acts as a tumor suppressor by inhibiting estrogen receptor α activity in breast cancer cells}, author={Zi-Jian Lan and Yunhui Hu and Sheng Zhang and Xian Li and Huaxin Zhou and Jixiang Ding and Carolyn M Klinge and Brandie N. Radde and Austin John Cooney and Jin Zhang and Zhenmin Lei}, journal={Breast Cancer Research and Treatment}, year={2016}, volume={158}, pages={263-276} }