Presence of functional luteinizing hormone/chorionic gonadotropin (hCG) receptors in human breast cell lines: implications supporting the premise that hCG protects women against breast cancer.

We investigated MCF-7 and MDA-MB-231 human breast cancer cell lines and immortalized mammary epithelial HBL-100 cells for the presence of functional LH/hCG receptors. The results revealed that all three breast cell lines contain LH/hCG receptor mRNA transcripts and receptor proteins that can bind 125I-hCG. The MCF-7 cells, however, contain higher levels than the others. Culturing MCF-7 cells with highly purified hCG resulted in a dose- and time-dependent significant decrease in steady-state estradiol receptor mRNA and protein levels as compared to controls, with the maximal decrease occurring after 4 h of culture with 10 ng/ml hCG. The studies on cell growth demonstrated that hCG treatment in the presence of minimal or no fetal bovine serum had a time-dependent significant inhibitory effect on MCF-7 and HBL-100, but not on MDA-MB-231 cells. In summary, our results demonstrate that human breast cell lines contain functional LH/hCG receptors. The hCG effects in MCF-7 cells are consistent with a premise that hCG protects women against breast cancer.