Research On The Biological Function Of A Co-Regulator Of Estrogen Receptor GA5

Objective To investigate the role and molecule mechanism of estrogen receptorco-factor GA5on breast cancer.Methods Co-immunoprecipitation was used to identify if there exists interactionbetween GA5and ERβ proteins. The protein level of GA5in6different breast cancercell lines was detected by using Western blot method. The protein level of GA5inbreast cancer tissues and the matched paratumor normal tissues was detected by usingWestern blot method. GA5cDNA was amplified from breast library and cloned intothe eukaryotic expression vector pCDH-EFI-MCS-T2A-puro. Western blot wasperformed to identify the lentivirus-mediated expression of GA5in ZR75-1cells.Real-time PCR and Western blot were performed to identify the lentivirus-mediatedknockdown of GA5. Growth curve assay was measured to determine the cellularproliferation rate of GA5over-expression and knockdown on the growth of ZR75-1cell line; soft agar assay was performed to evaluate the influence of the ability to formcell clone; and plate colony formation assay was used to measure the cell colonyformation rate.Results The interaction between GA5protein and ERβ protein was confirmed byco-immunoprecipitation analysis. According to the results of Western blot, comparedwith that in paratumor tissues, GA5was lower-expressed in carcinoma tissues. Thestably over-expression and knockdown of GA5transfected breast cancer cell lines wasestablished. The cellular proliferation rate, influence of the ability to form cell cloneand cell colony formation rates were statistically decreased in over-expression GA5groups, and increased in GA5siRNA groups.Conclusion GA5protein integrated with ERβ protein in vivo. GA5waslower-expressed in breast cancer tissues than paratumor normal tissues. EstablishedGA5over-expression and knockdown cell lines. GA5could repress the growth of breast cancer cells.