DOI
https://doi.org/10.25772/R071-W680
Defense Date
2012
Document Type
Thesis
Degree Name
Master of Science
Department
Pharmacology & Toxicology
First Advisor
David Gewirtz
Abstract
Breast cancer is the most commonly observed cancer type in women and is the second leading cause of cancer death in women. Radiation can be used to debulk tumors prior to surgery as well as to treat patients after surgery and/or chemotherapy. Previous studies from our laboratory have shown that the anti –malarial drug chloroquine sensitizes breast cancer cell lines to radiation by suppression of autophagy which is a conservative catabolic process that can be cytoprotective. The scientific literature has demonstrated that many tumor cell systems undergo cytoprotective autophagy and that pharmacological or genetic inhibition of autophagy leads to other modes of cell death such as apoptosis. Acridine orange staining was used for determination of acidic vacuole formation, an indication of autophagy and DAPI/TUNEL staining was used to identify apoptotic cells. Our studies in Hs578t breast tumor cells show the lack of sensitization by chloroquine upon autophagy inhibition with minimal apoptosis when cells are treated with 5 × 2Gy radiation. The extent of apoptosis was not increased upon autophagy inhibition by Chloroquine as determined by DAPI/TUNEL assays and quantified by Flow Cytometry using AnnexinV/PI. The potential role of senescence in the effects of radiation in the Hs578t cells was determined with the use of β-Galactosidase dye staining for senescence. It appears from these studies that autophagy need not to be cytoprotective in all breast cancer cell lines. Additional studies are in progress to effort to identify the factors that might distinguish between cytoprotective and non-cytoprotective autophagy.
Rights
© The Author
Is Part Of
VCU University Archives
Is Part Of
VCU Theses and Dissertations
Date of Submission
December 2012