Date of Award
Master of Science (MS)
Paras Mishra, Joseph Dolence, Hector Palencia
Diabetes;microRNA;Polyamine Enzymes;Polyamines;Triple Negative Breast Cancer
Breast cancer (BC) is the second leading cause of death in women. Co-existence of diabetes and BC can be lethal, leading to higher mortality than BC alone. TNBC is highly refractive, heterogenous, and resistant to most chemotherapies. Polyamines play a role in cell growth and are elevated in cancer, though their role in diabetic TNBC has not been explored. We hypothesized that high glucose/diabetic conditions increase TNBC cell proliferation through modification of enzymes in the polyamine pathway and that miR-133a would decrease TNBC cell proliferation. For this study, MDA-MB-231 and MCF-10A cell lines were both treated with normal (5mM) and high glucose (25mM) concentrations and effects on polyamine levels, polyamine enzyme, and cell proliferation were monitored. Polyamine levels were assayed using reverse phase HPLC, cell proliferation assessed using a fluorescence-based assay, and polyamine enzyme expression was monitored at mRNA and protein levels using RT-PCR and Western Blots, respectively. Polyamine inhibitor, alpha-difluoromethylornithine (DFMO, 5mM), was used in combination with glucose treatments. Further, miR-133a was used alongside glucose treatments. Under diabetic/high glucose conditions, putrescine levels were elevated in MDA-MB-231 cells, which correlated with higher cell proliferation. Polyamine enzyme activity of ODC increased (from ~75 pMolCO2/hr/mg protein to ~150 pMolCO2/hr/mg protein) and SMOX decreased (from ~0.4 pMolH2O2/min/mg protein to ~0.06 pMolH2O2/min/mg protein). DFMO reduced cell proliferation, however re-supplementation of spermidine and spermine restored cell proliferation, indicating cytostatic action. Interestingly, miR-133a significantly decreased cell proliferation under both normal and diabetic conditions. Cell proliferation increased with high glucose in MCF-10A cells also. Our study suggests that diabetic conditions advance TNBC and can induce cancerous states in breast epithelial tissue. Polyamine enzymes play an active role in this process, and further miR-133a shows promise and should be explored to determine its role in targeting the polyamine pathway to mitigate diabetic TNBC advancement.
Tofilau, Hadassha, "Polyamine Enzymes as Potential Targets for Cancer Therapeutics to Mitigate Diabetic Triple Negative Breast Cancer Advancement" (2022). Biology Theses, Dissertations, and Student Creative Activity. 16.