Normal MCF-12A Cells Research Articles

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

Abstract 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.

Abstract 5420: Normal mammary epithelial mitochondria introduced into human breast cancer cells results in inhibition of proliferation and increased drug sensitivity of the MCF-7 breast cancer cell line.

Abstract Warburg in the 1920s postulated that mitochondrial dysfunction alters metabolism in cancer. He observed in cancer cells aerobic glycolysis, which is the conversion of glucose to lactic acid in the presence of oxygen, the so called “Warburg effect” [1]. Mitochondrial dysfunction of cancer cells includes increased aerobic glycolysis, elevated levels of ROS, decreased apoptosis, and resistance to chemotherapeutic agents. We reported on the ultrastructural observations of mitochondria in human breast carcinoma cells [2]. There were three distinct groups: (1) mitochondria absent, (2) mitochondria present, (3) mitochondria present but sparse and abnormal. Tumors in the absent group were more anaplastic, aggressive, and resistant to treatment. We hypothesized that the introduction of normal mitochondria into cancer cells might restore mitochondrial function and inhibit cancer cell growth, and reverse chemoresistance. First we tested if mitochondria of normal mammary epithelial MCF-12A cells could enter into cultured human cancer cells. Then we determined if introducing normal mitochondria into cancer cells would inhibit proliferation. Finally we determined if addition of normal mitochondria increases the sensitivity of human breast cancer MCF-7 cells to chemotherapy. We found JC-1 stained mitochondria from normal mammary epithelial MCF-12A cells can enter into the cancer cell lines MCF-7, MDA-MB-231, and NCI/ADR-Res, but cannot enter normal MCF-12 A cells. The normal mitochondria from normal MCF-12 A cells suppressed the proliferation of MCF-7 and NCI/ADR-Res cells in a dose dependent pattern, but did not affect the proliferation of normal MCF-12A cells. The normal mitochondria from normal MCF-12A cells increased the sensitivity of human breast cancer MCF-7 cells to doxorubicin, Abraxane, and carboplatin. In conclusion the introduction of normal mammary mitochondria into human cancer cells inhibits cancer cell proliferation and increases the sensitivity of the MCF-7 human breast cancer cells to doxorubicin, Abraxane, and carboplatin. This phenomenon has never been reported, and the results support the role of mitochondrial dysfunction in cancer and suggest the possible use of targeted mitochondria as an adjunct to cancer therapeutics. Citation Format: Robert L. Elliott, Xian P. Jian, Jonathan F. Head. Normal mammary epithelial mitochondria introduced into human breast cancer cells results in inhibition of proliferation and increased drug sensitivity of the MCF-7 breast cancer cell line. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 5420. doi:10.1158/1538-7445.AM2013-5420

ESX induces transformation and functional epithelial to mesenchymal transition in MCF-12A mammary epithelial cells.

ESX is an epithelial-restricted member of a large family of transcription factors known as the Ets family. ESX expression has been shown to be correlated with Her2/neu proto-oncogene amplification in highly aggressive breast cancers and induced by Her2/neu in breast cell lines, but its role in tumorigenesis is unknown. Previously, we have shown that ESX enhances breast cell survival in colony-formation assays. In order to determine whether ESX can act as a transforming gene, we stably transfected MCF-12A human mammary epithelial cells with the ESX expression vector, pCGN2-HA-ESX. The MCF-12A cell line is immortalized, but nontransformed, and importantly, these cells fail to express endogenous ESX protein. We used pCGN2-HA-Ets-2 and pSVRas expression vectors as positive controls for transformation. Like HA-Ets-2 and V12-Ras, stable expression of ESX induced EGF-independent proliferation, serum-independent MAPK phosphorylation and growth in soft agar. Additionally, stable ESX expression conferred increased cell adhesion, motility and invasion in two-dimensional and transwell filter assays, and an epithelial to mesenchymal morphological transition. In three-dimensional cultures, parental and vector control (pCGN2) cells formed highly organized duct-like structures with evidence of cell polarity, ECM adhesion-dependent proliferation and cell survival, and lack of cellular invasion into surrounding matrix. Remarkably, the ESX stable cells formed solid, disorganized structures, with lack of cell polarity, loss of adhesion junctions and cytokeratin staining and loss of dependence on ECM adhesion for cell proliferation and survival. In addition, ESX cells invaded the surrounding matrix, indicative of a transformed and metastatic phenotype. Taken together, these data show that ESX expression alone confers a transformed and in vitro metastatic phenotype to otherwise normal MCF-12A cells.