Indole-3-carbinol disrupts estrogen receptor-alpha dependent expression of insulin-like growth factor-1 receptor and insulin receptor substrate-1 and proliferation of human breast cancer cells.
We previously established that Indole-3-Carbinol (I3C), a natural hydrolysis product of glucobrassicin in cruciferous vegetables, arrests the proliferation of estrogen-dependent human breast cancer cells and induces protein degradation of Estrogen Receptor-alpha (ER[alpha]). We demonstrate in human MCF-7 breast cancer cells that I3C ablates expression of Insulin-like Growth Factor Receptor-1 (IGF1R) and Insulin Receptor Substrate-1 (IRS1), downstream effectors of the IGF1 signaling pathway. Exogenous ER[alpha] reversed the I3C mediated loss of IGF1R and IRS1 gene expression demonstrating that down-regulation of ER[alpha] is functionally linked to I3C control of IGF1R and IRS1 expression. I3C disrupted binding of endogenous ER[alpha], but not Sp1, to ERE-Sp1 composite elements within the IGF1R/IRS1 promoters. Exogenous ER[alpha] abrogated, and combined expression of IGF1R and IRS1 attenuated, the I3C mediated cell cycle arrest. Therefore, I3C inhibits proliferation of estrogen-sensitive breast cancer cells through disruption of ER[alpha]-mediated transcription of cell signaling components within the IGF1 cascade.
Mol Cell Endocrinol. 2012 Nov 5;363(1-2):74-84
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|Title Annotation:||Cruciferous Vegetables|
|Article Type:||Brief article|
|Date:||Apr 1, 2013|
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