The effect of insulin on the chemosensitivity of cancer cells

Objective To investigate the effect and mechanism of insulin and hypoglycemia on the chemosensitivity of cancer cells. Methods Human colon cancer cells SW480, mouse colon cancer cells CT-26 and mouse breast cancer cells 4T1 were cultured and treated with insulin and chemotheraputic drugs, 5-fluorouracil or methotrexate. MTT assay was used to measure the cytotoxity. Fluorescence microscopy and flow cytometry were used to determine the effects of insulin on the uptake of fluorescent methotrexate by cancer cells. Mouse breast cancer cells 4T1 were inoculated into syngeneic BALB/C mice. Insulin was administrated to the mice before giving methotrexate and the therapeutic effect was monitored. Results (1) Insulin enhanced the chemocytotoxity of chemotheraputic drugs on cancer cells by 4. 1% to 11.5%;(2) Insulin increased the uptake of fluorescent methotrexate by cancer cells in vitro by 141. 9% ;(3) Insulin and hypoglycemia enhanced the chemotherapeutic effect of methotrexate on mouse breast cancer models by 20. 1%. Conclusion Insulin and hypoglycemia increase absorption of chemotherapeutic agents by cancer cells and enhance the chemosensitivity of cancer cells. Key words: Cancer; Chemotherapy; Insulin; Hypoglycemia