The Effects of Bcl-2 and Bcl-XL Expression on the Radiation Response of MCF-10A Cells

Abstract

<p>Ionizing radiation is used to screen for, diagnose, and treat breast cancer. Noncancerous breast cells are exposed to a range of doses as a result of these procedures in addition to the low levels of natural background radiation that they are always exposed to. With the consistent increase in medical radiation procedures, and the climbing rates of breast cancer in most populations, understanding the effects of these exposures is of interest and importance. Radiation exposure results in DNA double strand breaks which can trigger various cellular responses including cell cycle arrest, and cell death. Apoptosis is a form of highly regulated cell death that is controlled by the Bcl-2 family of proteins. Bcl-2 and Bcl-XL are anti-apoptotic proteins that are commonly overexpressed in human cancers including breast cancer. This thesis was focused on investigating the effects of Bcl-2 and Bcl-XL expression on the radiation response of human mammary epithelial cells. Bcl-2 and Bcl-XL were exogenously expressed in MCF-10A cells, and Bcl-XL expression was knocked down. Cytogenetic techniques were used to characterize the MCF-10A cells used. Automated image based assays were used to validate the anti-apoptotic effects of the exogenous proteins against known apoptotic stimuli, and to probe the effects of radiation exposure. The influence of Bcl-2 and Bcl-XL expression on the immediate and short term effects of radiation exposure was investigated using cell growth assays, flow cytometry, and</p>