Cancer continues to be a formidable threat to human health as the second leading cause of death in the United States. Many end-stage cancers frequently evolve into multidrug-resistant (MDR) forms, posing significant challenges in treatment design. To combat this, the Mancini Lab has recently devised a new mechanism of action known as Bystander-Assisted Immunotherapy (BAIT). The efficacy of BAIT relies on both influx into cancer cells for intracellular activation and efflux out of the cell to target nearby (bystander) immune cells. Since it is known that many MDR cancers overexpress efflux transporters such as P-gp, the efficacy of BAIT is enhanced with MDR. However, it is currently unknown how the cancer cells are taking up the BAIT prodrugs. We hypothesize that MDR cancer cells upregulate their expression of glucose transporter (GLUT) proteins in order to satisfy the cells’ substantial nutrient needs and increased reliance on glycolysis through the Warburg effect. In this study, we cultivated B16 cells with varying levels of resistance to the chemotherapeutic doxorubicin (DOX). We administered DOX incrementally, starting from 1 nM and doubling to 1 μM, to avoid immediate cytotoxicity and to study changes of GLUT expression on a finer scale. Preliminary findings from western blot and/or RT-qPCR reveal a decrease followed by an increase in GLUT1, a decrease in GLUT2, no change in GLUT3, and a sudden increase in GLUT4 with MDR. Immunofluorescence studies reveal a change in localization patterns of GLUT1. Other methods, such as flow cytometry and fluorescent sugar uptake experiments, will be conducted to explore various changes in GLUT expression and activity. If successful, this study will facilitate the optimization of influx for novel anti-cancer BAIT prodrugs and contribute new insights into the unique metabolic signature of MDR cancers.
Author(s): Emily Wang, Abbey Michaelson, Rock Mancini, Ph.D.
Advisor: Rock Mancini, Chemistry and Biochemistry
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