Statins inhibit the growth of variant human embryonic stem cells and cancer cells in vitro but not normal human embryonic stem cells

Background and purpose: Statins inhibit proliferation of various human cancer cell lines in vitro. As human embryonic stem cells (hESCs) possess neoplastic-like properties we have evaluated the role of various statins on karyotypically normal hESCs (HES3 and BG01), abnormal hESCs (BG01V) and breast adenocarcinoma cells (MCF-7) to evaluate whether the mode of action of the statins was via a stemness pathway. Experimental approach: All cell lines were treated with simvastatin, pravastatin, lovastatin and mevastatin (1 mu mol.L-1 to 20 mmol.L-1) up to 7 days and their effects on cell proliferation, cell cycle, apoptosis and pluripotency studied. Key results: All four statins did not inhibit HES3 and BG01 proliferation, but BG01V and MCF-7 were inhibited by simvastatin, lovastatin and mevastatin. These inhibitory effects were reversed by the endogenous isoprenoids, farnesylpyrophosphate and geranylgeranylpyrophosphate. Terminal deoxynucleotidyl transferase biotin-dUTP nick end labelling and cell cycle assay confirmed apoptosis in BG01V and MCF-7. Stem cell surface markers [stage-specific embryonic antigen-4, tumour rejection antigen-1-81, octamer-4 (OCT-4)] were expressed in HES3 and BG01, but not in BG01V cells, even after prolonged treatment with simvastatin. In BG01V and MCF-7, the pro-apoptotic Bcl-2-associated X protein genes were up-regulated, while the antiapoptotic BCL2 and SURVIVIN genes were down-regulated. Expression of the stemness-related genes namely, the growth differentiation factor-3, NANOG and OCT-4 was decreased in BG01V compared with BG01 and HES3. Conclusions and implications: Normal hESCs were resistant to prolonged exposure to statins over a range of doses, compared with BG01V and MCF-7, probably because of genetic and behavioural differences. The statins not only have anti-cancer properties but can suppress abnormal hESCs thus promoting growth of normal hESCs in vitro. British Journal of Pharmacology (2009) 157, 962-973; doi:10.1111/j.1476-5381.2009.00241.x; published online 11 May 2009