Background: Cervical cancer is the most common cancer in Indian females and is associated with infection with high-risk human papillomaviruses (HPVs). Prolonged use of oral contraceptives has been established as a risk factor for cervical cancer which is mediated by elevated estradiol level. Berberine has emerged as a potential anticancer agent in various cancers. The present study investigated the effect of bereberine on estradiol pretreated cervical cancer cell lines HeLa, SiHa and C33A.
Methods: Cervical cancer cells were cultured in DMEM/RPMI/MEM medium supplemented in 10% FBS in a humidified atmosphere of 95% air and 5% CO2 at 37°C and were treated with estradiol for 24 hr followed by 50 µM and 75 µM Berberine for 24 hrs standardized using MTT assay. Apoptosis was measured by flow cytometery. Telomerase activity was studied using PCR ELISA. The expression of various proliferation proteins like PCNA, p16 was assessed by ICC. Expression of viral oncoprotein E6 and E7, Cyclin D1, p53 was assessed by Western blotting.
Results: Treatment of cervical cancer cells with estradiol resulted in increased proliferation after 24 hrs in HPV positive cell lines HeLa and SiHa but no proliferation was observed in HPV negative cell line C33A. Elevation of telomerase activity, viral oncoprotein E6 and E7, PCNA, p16 and cyclin D1 was seen in HPV positive cell lines on pretreatment by estradiol, On the other hand after post treatment by berberine for 24 hrs levels of E6, E7, PCNA and cyclin D1 were reduced while the level of telomerase and p16 were unaltered. Furthermore, estradiol pretreated HPV negative cell line C33A on treatment by berberine shows reduction in level of telomerase, PCNA, p16 and activation of p53 tumor suppressor protein, thus demonstrating the importance of HPV viral proteins in estradiol-induced carcinogenesis.
Citation Information: Cancer Prev Res 2010;3(12 Suppl):A45.