Metformin Modulates Cyclin D1 and P53 Expression to Inhibit Cell Proliferation and to Induce Apoptosis in Cervical Cancer Cell Lines

Abstract

Background: Cervical cancer is one of the most prevalent gynecological cancers worldwide and contributes in high<br />mortality of Indonesian women. The efficacy of chemotherapy as a standart therapy for cervical cancer decreases because<br />it frequenly rises adverse effects. Recent studies have found that metformin has a potential anticancer effect mostly<br />through reduction of cyclin expression and activation of Activated Adenosine Monophosphate Kinase (AMPK). This<br />study aimed to investigate the effect of metfomin on expression of cyclin D1 and p53 and apoptosis in HeLa cancer cell<br />line. Methods: HeLa cells were treated with various doses of metformin and doxorubicin as a positive control. Cytotoxic<br />effect of metformin was determined using the MTT assay. Immunocytochemistry was used to assess cyclin D1 and p53<br />expression and apoptosis levels of treated HeLa cells were analyzed using flowcytometry. Data of cyclin D1 expression<br />was statistically analyzed using the Kruskal-Wallis test followed by the Tamhane test, whilst ANOVA and Tukey post<br />Hoc tests were used to analyze data of p53 and apoptosis level. The significant value was p< 0.05. Results: Metformin<br />was able to inhibit proliferation of HeLa cells with IC50 60 mM. HeLa cells treated with 60 and 120 mM metformin<br />had lower cyclin D1 expression than HeLa cells treated without metformin and reached a significant difference (p=<br />0.001). Moreover, 30 mM or higher doses of metformin increase significantly p53 expression (p< 0.001). Induction of<br />apoptosis was observed in HeLa cells treated with all doses of metformin and reached statistically difference (p= 0.04<br />and p < 0.001). Conclusion: Metformin can modulate cyclin D1 and p53 expression in HeLa cancer cell line, leading<br />to inhibition of cell proliferation and induction of apoptosis. Other cyclin family members, CDK inhibitors and AMPK<br />signaling should be further investigated in order to know mechanism of metformin action.