The Effect Of Insulin On Chemotherapeutic Drug Sensitivity In Human Breast Cancer Cell Line In Vitro

[Objective] To investigate the effect and mechanism of insulin, as a metabolic promoter, on chemotherapeutic drug DDP, ADM, 5-Fu, Vp-16 and NVB sensitivity in human breast cancer cells and then offer evidence for clinical application.[Methods] Human breast cancer cells were cultured and inoculated into the wells. The chemotherapeutic drug were PDD ,5-Fu, ADM, NVB and Vp-16. Insulin was used as inducement. Cell activity and cell metabolism were assessed by MTT assay and cell count so as to reflect the cytotoxity of the anti-tumor agent and the effects combined with insulin . The changes in Cell cycle of every groups were examined by flow cytometry(FCM). A11 experimental data were analyzed with one-way ANOVA and linear correlation and processed by SPSS 10.0. There was a statistical significance when P<0.05.[Results]1. In the test of finding the revulsive concentration of insulin , We found that Insulin promoted the cell metabolism with the concentration 0.5-16mu/ml and this effect were escalated with the higher concentration. Concentration groups of 8.0mu/ml and 16.mu/ml had significant differences compared with other groups(p<0.01) .2. In the test of finding the best inducement time of insulin, insulin with concentration of 7.5mu/ml were added.The result showed that the best inducement time of insulin were 8-18h groups and there had significant differences compared with other groups (p<0.01 ) .3. In the test of cell count, Human breast cancer cells were cultured and the insulin with concentration of 7.5mu/ml were added. From the result we concluded that Insulin promoted the cell metabolism with the concentration 7.5mu/ml (9-18 hours) and this conclusion consistent with MTT assay.4. In the test of finding the chemotherapeutic drug concentration, the analysisshowed that inhibitory rate had a linear correlation with chemotherapeutic drug. Based on the result of MTT assay, we selected the concentration of 20% or 30% inhibitory rate (IC20 or IC30) as the concentration of chemotherapeutic drug. results:ADM IC₂₀=0.36ug/ml,5-Fu IC₂₀=28.Oug/ml, DDP IC₂₀=5.27ug/ml, Vp-16 IC₃₀=70.09 ug/ml, NVB IC₃₀=7.09 ug/ml.5. In the test of Insulin enhanced the sensitization on human breast cancer cells, Insulin(7.5 mu/ml) added before adding chemotherapeutic drug 9-15h, enhanced the chemocytotoxity on human breast cancer cells as indicatcd by MTT colorimetry. The best suitable concentration of Insulin were 2.0-16.0mu/ml, which can promote the sensibility of chemotherapeutic drug.6. The percents of S phase of Insulin from 3h to 24h were different and the increased S cell cycle were observed in phase synchronized MDA-MB-453 cell treated with 7.5mu/ml of insulin. Time groups of 18h had significant differences compared with other groups. The mechanisms may be related to increasing the S phase blocking and which effect can be synergistic with 5-Fu and ADM.[Conclusion]1. As a reversible metabolic promoter, Proliferation of human breast cancer cell line can be induced by insulin in vitro, at the condition of insulin (8.0-16.0mu/ml, 8-18h)-treated MDA-MB-453 cells increased both in dose-dependent manner. More over, a increased S cell cycle are observed in phase synchronized MDA-MB-453 cell treated with 7.5mu/ml of insulin.2. Insulin could sensitize MDA-MB-453 to the anticancer activity of 5-Fu, ADM, DDP, VP-16 and NVB in vitro. The key of improving the chemotherapeutic effect is t-he selection of the inducing occasion of revulsant and concentration. It is the best inducing state when insulin is used before adding chemotherapeutic drugs 9-15h, concentration 2.0-16.0mu/ml. The mechanisms may be related to increasing the S phase blocking and which effect can be synergistic with 5-Fu and ADM.3. It is possible to increase the growth and metabolism of cancer cells first so as to enhance the chemosensibility , and then administer chemotherapeutic agents , thus improving their therapeutic effects.