Role of Calreticulin Acetylation on Trafficking in Prostate Cancer

Prostate cancer is the second leading cause of cancer related deaths in American males, and although death rates have declined, it is still the most diagnosed cancer in males. Having a better understanding of prostate cancer will help decrease these rates. Calreticulin (CRT) is an Endoplasmic Reticulum (ER) resident chaperone protein, known to be expressed and regulated by androgen in

prostatic epithelial cells. CRT has been found to migrate to the cell surface in incidences of cancer where it promotes phagocytic uptake of cancer cells by the immune system. Although surface exposed CRT concentrations increase in several cancer types, both up and down regulation has been reported for prostate cancer. Therefore, one goal of this project is to investigate surface exposed CRT

expression in prostate cancer. The method of CRT trafficking to cell surface is unknown but cellular environment and post-translational modifications may contribute. A proteome-wide study found numerous proteins to be acetylated in prostate cancer, yet no studies have focused on acetylation of CRT in prostate cancer. Therefore, another objective of the proposed research project is to evaluate

the role of CRT acetylation on its trafficking to the cell surface in prostate cancer. My preliminary data suggests CRT structure changes upon binding of acetyl group donor. It also shows double expression of lysine acetylation and calreticulin present at the cell surface of prostate cancer cells and prostate

cancer tissue samples. Therefore, I hypothesize that CRT acetylation increases its trafficking to the cell surface in prostate cancer. To test this hypothesis, I propose three Specific Aims: 1) Investigate trafficking of CRT isoforms in prostate cancer cells, using fluorescently tagged wild type CRT, KDEL

deficient CRT, and CRT with mutated acetylation sites; 2) Understand method and partners of CRT trafficking, using protein pull down assays followed by advanced proteomic analysis of isoforms introduced prostate cancer cell lines; 3) Identify expression and location of CRT in prostate cancer tissue, using immunohistochemical analysis of CRT in a cohort of prostate cancer patients. This K01

proposal is designed to build upon my training background in protein structure/ function changes upon ligand binding and expand my skills and knowledge as a translational cancer disparities researcher. My scientific advisory committee is composed of accomplished scientists with expertise in prostate cancer, cancer health disparities, proteomics, molecular biology, and tumor

microenvironment. The program outlined in this K01 proposal will propel me into an independent scientific career through rigorous career development activities tailored to my specific research and career goals.