P0101 Metformin inhibits cyclin D1 expression in a p53-deficient colon cancer cell line in vitro

Abstract

Background Metformin is a biguanide that is used as first-line therapy for diabetes mellitus. It regulates metabolic profiles in the treatment of diabetes mellitus. Metformin has a potential anticancer effect, which could be helpful for patients with metabolic-related cancers such as colon cancer. This study aims to explore the anticancer role of metformin in the inhibition of cyclin D1 as a regulator of the cell cycle and to analyse the molecular target of metformin in colon cancer. Methods WiDr colon cancer cell lines were obtained from the parasitology laboratory of Gadjah Mada University. WiDr cell lines were treated with metformin at concentrations of 5 mmol/l, 10 mmol/l, and 20 mmol/l and incubated in 37 °C and 5% CO2 conditions. MTT assays were done to assess tumour-cell viability. Subsequently, we used immunohistochemistry to measure cyclin D1 expression. Cyclin D1 expression was quantified by H score using percentage and intensity for calculation. ANOVA was used to compare cell viability between groups. Comparisons of H score between groups were performed by Kruskal–Wallis for non-parametric tests. Findings Metformin significantly decreased cell viability at all concentrations by 70.20 ± 11.08 (p = 0.009), 67.93 ± 12.95 (p = 0.006), and 58.37 ± 13.08 (p = 0.001), respectively. Subsequently, metformin significantly down-regulated cyclin D1 expression at 10 mmol/l (p = 0.031) and 20 mmol/l (p = 0.0001) concentrations. Interpretation Our results suggest that metformin could inhibit colon cancer proliferation in p53 independent cell lines. Cyclin D1 might be a molecular target of metformin in p53-mutant colon cancer. Metformin is a biguanide that is used as first-line therapy for diabetes mellitus. It regulates metabolic profiles in the treatment of diabetes mellitus. Metformin has a potential anticancer effect, which could be helpful for patients with metabolic-related cancers such as colon cancer. This study aims to explore the anticancer role of metformin in the inhibition of cyclin D1 as a regulator of the cell cycle and to analyse the molecular target of metformin in colon cancer. WiDr colon cancer cell lines were obtained from the parasitology laboratory of Gadjah Mada University. WiDr cell lines were treated with metformin at concentrations of 5 mmol/l, 10 mmol/l, and 20 mmol/l and incubated in 37 °C and 5% CO2 conditions. MTT assays were done to assess tumour-cell viability. Subsequently, we used immunohistochemistry to measure cyclin D1 expression. Cyclin D1 expression was quantified by H score using percentage and intensity for calculation. ANOVA was used to compare cell viability between groups. Comparisons of H score between groups were performed by Kruskal–Wallis for non-parametric tests. Metformin significantly decreased cell viability at all concentrations by 70.20 ± 11.08 (p = 0.009), 67.93 ± 12.95 (p = 0.006), and 58.37 ± 13.08 (p = 0.001), respectively. Subsequently, metformin significantly down-regulated cyclin D1 expression at 10 mmol/l (p = 0.031) and 20 mmol/l (p = 0.0001) concentrations. Our results suggest that metformin could inhibit colon cancer proliferation in p53 independent cell lines. Cyclin D1 might be a molecular target of metformin in p53-mutant colon cancer.