THE EFFECT OF OXIDATIVE STRESS ON THE ATTACHMENT OF METASTATIC PROSTATE CANCER CELLS TO HUMAN BONE MARROW ENDOTHELIAL CELLS

Date
2017-05
Journal Title
Journal ISSN
Volume Title
Publisher
University of Delaware
Abstract
Prostate cancer (PCa) is both the most common and the third deadliest cancer among American men. Most of the mortality associated with PCa stems from metastasis of the cancer to bone (1,2), leading to my previous hypothesis that prostate cancer cells preferentially adhere to human bone marrow endothelial (HBME) cells. Previous experiments in our lab have confirmed this preference and I investigated the physiological factors that contribute to PCa metastasis. The initial goal of this project was to determine if fluid shear stress would increase expression of membrane adherence proteins on HBME cells thereby increasing the ability of PCa cells to adhere to these cells. I further postulated that adhesion of prostate cancer cells to HBME cells is regulated by nitric oxide (NO), with reduced levels of NO leading to increased PCa adhesion. To evaluate the relationship of NO to cell adhesion we performed adhesion assays under fluid shear and in the presence of NG-nitro-L-arginine methylester (L-NAME), an inhibitor of NO synthase (3). Using calcein loaded PCa cells, I found that the number of labeled cells was higher in the non-sheared, or static, samples that when compared to sheared cells. Indicating that PCa cell attachment to the HBME cell monolayer was also higher in these samples. Inhibition of NO synthesis with L-NAME also increased PCa cell attachment in sheared samples but was not effective in the static samples. Because my data did not support my original hypothesis, I proposed that Oxidative Stress (OS) could be another potential factor that could influence PCa adhesion to HBMECs. OS results from an imbalance in the production of reactive oxygen species (ROS) and the antioxidants required to metabolize ROS (4). I hypothesized that OS could play a role in increasing the expression of cell adhesion molecules (CAMs) on the membrane of HBMECs therefore increasing the ability of PCa cells to attach to them. To test my hypothesis, I used DCFH-DA to confirm that we could artificially induce OS in HBMECs and an adhesion assay similar to our previous studies to measure its effect on adhesion. I found that inducing OS in endothelial cells triggered increased PCa cell attachment to HBMEC cells however further studies will be needed to confirm that the increased attachment is due to increased CAMs. Future studies will also include experimental design modifications such as increasing the duration that the endothelial cells are sheared to determine if long term shear produces a different effect than short term shear. Completion of these studies may lead to insight into the racial differences in OS and NO production and the impact of this racial disparity on prostate cancer occurrence and metastasis.
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Keywords
Biology, Biological Sciences, ATTACHMENT of METASTATIC PROSTATE CANCER CELLS
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