Less than 9% of pancreatic ductal adenocarcinoma (PDAC) patients survive 5 years beyond diagnosis. A primary reason for the low survival rate is that the best available treatments are not that effective for many patients, and many tumors become resistant to them. A treatment approach that could sensitize tumor cells to chemotherapy would be a major advance in the treatment of PDAC, the most deadly of the major cancer types in the United States. The long term goals for this research are to enhance the biomedical research environment at North Dakota State University and to identify clinically-relevant therapeutic targets to improve treatment outcomes for PDAC patients. The objectives for this application are to provide training opportunities for undergraduate and graduate students and to establish the tumor-promoting roles of the antioxidant enzyme glutathione S-transferase pi 1 (GSTP1) in PDAC models. The central hypothesis is that inhibition of GSTP1 can sensitize PDAC cells to platinum-based chemotherapy and alter gene and metabolite expression profiles that limit tumor growth. To test the central hypothesis, three Specific Aims are proposed: 1) Determine the chemosensitizing effects of GSTP1 inhibition for PDAC cells, 2) Identify the gene expression changes associated with GSTP1 inhibition in PDAC cells, and 3) Identify the metabolome changes associated with GSTP1 inhibition in PDAC cells. For the first aim, cell culture and mouse models will be used to determine the degree to which pharmacological and functional GSTP1 inhibition influence sensitivity to platinum-based chemotherapy. For the second aim, our transcriptome data will be validated in GSTP1 knockdown PDAC cell lines and in PDAC cells treated with a GSTP1 inhibitor. Functional assays will be performed to further identify anti-tumor mechanisms associated with GSTP1 inhibition. For the third aim, targeted metabolomics will be used to determine the metabolite expression changes in PDAC cells when GSTP1 function is impaired. The approach is innovative because it will involve evaluating a molecular target that has not been studied before in PDAC. The proposed research is significant because it is expected to advance the fields of PDAC treatment and oxidative stress biology by establishing GSTP1 as a new therapeutic target for PDAC treatment and revealing novel cellular responses to inhibition of this important antioxidant enzyme. The results from this project are expected to expand understanding of how antioxidant enzymes can be targeted for chemosensitization of tumor cells. Such knowledge has the potential to change the field of chemotherapy and result in more effective cancer treatments. Given that treatment options for PDAC are currently lacking, there is an urgent need to identify safe and more effective treatment approaches for this highly deadly disease. Finally, this project will have a tremendous impact on the undergraduate and graduate students involved, and the biomedical research capacity of North Dakota State University.
Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal disease for which new therapeutic targets are critically needed to improve treatment outcomes and enhance patient survival. The proposed research is relevant to public health because it will evaluate the antioxidant enzyme GSTP1 as a new therapeutic target to sensitize PDAC cells to chemotherapy, and will identify novel molecular responses to GSTP1 inhibition that may lead to additional strategies to treat cancer.