Insulin promotes progression of colon cancer by upregulation of ACAT1

Background: Insulin resistant and the progression of cancer is closely related. The aim of this study was to investigate the effect of insulin on the proliferation and migration of colon cancer cells and its underlying mechanism. Methods: Colon carcinoma tissues from the 80 cases of colon cancer patients were collected. Immunohistochemistry was used to detect the expression of acyl coenzyme A: cholesterol acyltransferase1 (ACAT1), and we analyzed the correlation between hyperglycemia and ACAT1, hyperglycemia and metastasis. CCK8 assay and transwell assay were used to investigate the effect of different concentrations of insulin and ACAT1siRNA on human colon cancer cell line HT-29. ACAT1 mRNA expression and protein level in HT-29 cells were determined by real-time quantitative PCR and western blotting, respectively. Results: Biopsies from patients with colon carcinoma showed hyperglycemia links ACAT1, lymph nodes metastasis and distant metastasis. Insulin markedly promoted cell proliferation and migration in human colon cancer HT-29 cells. Moreover, ACAT1mRNA expression and protein level were increased by insulin. ACAT1siRNA resulted in a complete inhibition of the ACAT1 mRNA expression. Consequently insulin-triggered cell proliferation and migration on colon cancer cells were inhibited. Conclusion: The progression of colon cancer has a positive correlation with hyperinsulinemia. Insulin-triggered cell proliferation and metastatic effects on colorectal cancer cells are mediated by ACAT1. Therefore, insulin could promote colon cancer progression by upregulation of ACAT1, which maybe is a potential therapeutic target for colon cancer.