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Background: Metabolic reprogramming within cancer cells has been recognized as a potential barrier to chemotherapy. Additionally, metabolic tumor heterogeneity is the one of factors behind discernible hallmarks such as drug resistance, relapse of the tumor and the formation of secondary tumors., Methods: In this paper, cell-based assays including PI/annexin V staining and immunoblot assay were performed to show the apoptotic cell death in MCF-7 cells treated with DOX. Further, MCF-7 cells were lysed in a hypotonic buffer and the whole cell lysate was purified by a novel and specifically designed metabolite (~ 100 to 1000 Da) fractionation system called vertical tube gel electrophoresis (VTGE). Further, purified intracellular metabolites were subjected to identification by LC-HRMS technique., Results: Cleaved PARP 1 in MCF-7 cells treated with DOX was observed in the present study. Concomitantly, data showed the absence of active caspase 3 in MCF-7 cells. Novel findings are to identify key intracellular metabolites assisted by VTGE system that include lipid (CDP-DG, phytosphingosine, dodecanamide), non-lipid (N-acetyl-D-glucosamine, N1-acetylspermidine and gamma-L-glutamyl-L-cysteine) and tripeptide metabolites in MCF-7 cells treated by DOX. Interestingly, we reported the first evidence of doxorubicinone, an aglycone form of DOX in MCF-7 cells that are potentially linked to the mechanism of cell death in MCF-7 cells., Conclusion: This paper reported novel methods and processes that involve VTGE system based purification of hypotonically lysed novel intracellular metabolites of MCF-7 cells treated by DOX. Here, these identified intracellular metabolites corroborate to caspase 3 independent and mitochondria induced apoptotic cell death in MCF-7 cells. Finally, these findings validate a proof of concept on the applications of novel VTGE assisted purification and analysis of intracellular metabolites from various cell culture models.

Objective: To investigate the expression of zinc finger transcription factors-Snail and E-cadherin in adriamycin-resistant human breast cancer MCF-7/ADM cells and non-resistant MCF-7 cells., Study Design: An experimental study., Place and Duration of Study: The Affiliated Cancer Hospital of Nanjing Medical University and Jiangsu Cancer Hospital, and Jiangsu Institute of Cancer Research, China, from April 2017 to March 2018., Methodology: Real-time quantitative PCR technology was used to detect the expression levels of Snail mRNA and E-cadherin mRNA in normal breast cells, adriamycin-resistant human breast cancer MCF-7/ADM cells and non-resistant MCF-7 cells. Western blot was used to detect the expression levels of proteins of Snail and E-cadherin in normal breast cells, adriamycin-resistant human breast cancer MCF-7/ADM cells and non-resistant MCF-7 cells., Results: The expression of Snail mRNA and protein in adriamycin-resistant human breast cancer MCF-7/ADM cells was significantly higher than that in normal breast cells (p<0.001) and non-resistant MCF-7 cells (p<0.001). The expression of E-cadherin mRNA and protein in adriamycin-resistant human breast cancer MCF-7/ADM cells was significantly lower than that in normal breast cells (p<0.001) and non-resistant MCF-7 cells (p<0.001)., Conclusion: Adriamycin-resistant human breast cancer MCF-7/ADM cell strains had high expression of Snail and low expression of E-cadherin. This points out to a new research direction for the targeted therapy of drug-resistant breast cancer cells, and provides clinical guidance for breast cancer therapy and prognosis evaluation.

Macrophage colony-stimulating factor is a vital factor in maintaining the biological function of monocyte-macrophage lineage. It is expressed in many tumor tissues and cancer cells. Recent findings indicate that macrophage colony-stimulating factor might contribute to chemoresistance, but the precise mechanisms are unclear. This study was to explore the effect of macrophage colony-stimulating factor on doxorubicin resistance in MCF-7 breast cancer cells and the possible mechanism. In the study, the human breast cancer cells, MCF-7, were transfected with macrophage colony-stimulating factor. We document that cytoplasmic macrophage colony-stimulating factor induces doxorubicin resistance and inhibits apoptosis in MCF-7 cells. Further studies demonstrated that cytoplasmic macrophage colony-stimulating factor-mediated apoptosis inhibition was dependent on the activation of PI3K/Akt/Survivin pathway. More importantly, we found that macrophage colony-stimulating factor-induced autophagic cell death in doxorubicin-treated MCF-7 cells. Taken together, we show for the first time that macrophage colony-stimulating factor-induced doxorubicin resistance is associated with the changes in cell death response with defective apoptosis and promotion of autophagic cell death.