<![CDATA[Breast cancer is one of the most common cancers worldwide, with a high incidence rate. Doxorubicin is a chemotherapeutic agent used in breast cancer management. Nevertheless, chemoresistance remains a major challenge in breast cancer chemotherapy. Insulin contributes to chemoresistance through its mitogenic and prosurvival activities. To date, studies evaluating the effect of insulin on the viability of Luminal A breast cancer cells (T-47D) under doxorubicin exposure remain limited. This study aimed to analyse the effect of insulin supplementation on the viability of Luminal A breast cancer cells (T-47D) exposed to doxorubicin. An in vitro experimental study was conducted using T-47D cells treated with doxorubicin at various concentrations (3.13, 6.25, 12.5, 25, 50, and 100 μg/mL), with and without insulin supplementation. Cell viability was assessed using the 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and analysed using a paired-samples t-test. T-47D cells receiving insulin supplementation showed higher viability than those without insulin across all tested doxorubicin concentrations, with statistically significant differences (p < 0.05). The fold change in viability between the insulin and non-insulin groups increased with rising doxorubicin concentrations. In conclusion, insulin affects the viability of Luminal A breast cancer T-47D cells exposed to doxorubicin, indicating reduced cellular sensitivity to the cytotoxic effects of doxorubicin. ]]>
