The Development Of New Screening System And Identification Of A Novel Serm That Acts Through Htert And Induce Apoptosis In Vitro And In Vivo

Drug screening is a crucial step in the field of drug discovery. Cell‐based screening of anti‐cancer drugs using MTT based colorimetric assay is widely used standard method. It has many error prone steps and takes quite a long time to finish. Here we report the development of a new cell‐based drug screening system using Green Fluorescence Protein (GFP) that is simple, time saving and reliable. Our data show that this assay system is comparable or better than MTT‐based assays in terms of sensitivity and accuracy for cell growth curve, inhibition by anticancer drugs, dosage response, as well as in IC50determination of anti‐cancer drugs. Using this screening method we screened a novel SERM, Compound11, and found that it had a better cytotoxic activity than tamoxifen. The new SERM showed dose and time dependent cytotoxicity in breast cancer MCF7cells and ovarian cancer SKOV3cells. Luciferase assay revealed the new SERM to be a multiple modulator as it decreased the estrogen induced luciferase activity of tk‐ERE promoter, antagonizing the E2effect and also induced the dexamethasone induced effect on tk‐GRE promoter. The new SERM also repressed hTERT promoter activity in MCF7cell lines but not in SKOV3. Western blot showed consistency with luciferase assay as hTERT protein expression was reduced after the treatment with Compound11. Treatment of MCF7cells with Compound11caused the translocation of hTERT from nucleus to cytoplasm. Moreover this new SERMs was able to suppress the SKOV3tumor growth on xenograft nude mice model. All these findings suggest that Compound11regulates hTERT expression in cell type specific manner and can be a potential anticancer drug for breast and ovarian carcinoma.