Abstract A42: Exogenous normal mammary epithelial mitochondria increase the drug sensitivity of human breast cancer MCF-7 cells

The mitochondrial dysfunction of cancer cells leads to the suppression of glucose oxidation, increased glycolysis, proliferated advantage, resistance to apoptosis and drug resistance. We hypothesize that the introduction of normal mitochondria into cancer cells will restore the mitochondrial function of cancer cells and increase drug sensitivity. We stained the mitochondria of the normal human mammary epithelial cell line MCF-12A with JC-1 dye, and found orange fluorescence (JC-1 aggregates in mitochondria due to high mitochondrial membrane potential) in the MCF-12A cells. We then isolated the JC-1 stained-mitochondria of the MCF-12A cells and co-cultured them with the cells of human breast cancer MCF-7 cell line. At 30 minutes after co-culture of MCF-7 cells with the isolated JC-1-stained mitochondria, the orange fluorescence was observed in the MCF-7 cells. The fluorescence continued to increase for at least 6 hours and was still detected at 24 hours. This demonstrated that exogenous normal mitochondria of MCF-12A can enter into MCF-7 breast cancer cells. In order to determine whether mitochondria of normal MCF-12A cells improve the sensitivity of breast cancer cells to chemotherapeutic drugs, we co-cultured MCF-7 cells for 24 hours with normal mitochondria of MCF-12A, aspirated off the media and treated the MCF-7 cells with the drugs doxorubicin, abraxane or carboplatin. We found that MCF-7 cells, treated with the normal mitochondria of MCF-12A, were more sensitive to doxorubicin, abraxane and carboplatin than non-treated MCF-7 cells. We also have RT-PCR results demonstrating that uptake of normal mitochondria by cancer cells down-regulates the expression of membrane glucose transporter GLUT3 in MCF-7 cells. In conclusion, we suggest that the introduction of normal cell mitochondria into cancer cells could restore cancer cell mitochondrial function and significantly impact cancer therapy. Citation Format: Xian-Peng Jiang, Jeff Philips, Robert L. Elliott, Jonathan F. Head. Exogenous normal mammary epithelial mitochondria increase the drug sensitivity of human breast cancer MCF-7 cells. [abstract]. In: Proceedings of the AACR Precision Medicine Series: Drug Sensitivity and Resistance: Improving Cancer Therapy; Jun 18-21, 2014; Orlando, FL. Philadelphia (PA): AACR; Clin Cancer Res 2015;21(4 Suppl): Abstract nr A42.