Approximately 8.3% of the US population has diabetes, which is manifested by the development of microvascular pathology in the retina, renal glomerulus and peripheral nerve, rendering diabetes a leading cause of blindness, end-stage renal disease and various debilitating neuropathies. Colorectal cancer is the 3rd most common cancer in both men and women, and it accounts for ~9% of all cancer deaths. Thus, a better understanding about the etiology for the development of diabetic complications and gastrointestinal cancer may lead to better strategies for the prevention and treatment of these diseases, thereby saving lives and improving the quality of life for numerous patients suffering from these diseases. Hyperglycemia in diabetic patients and exposure to N-nitroso compounds in the gastrointestinal track can both give rise to carboxyalkylating agents that can modify DNA. The long-term goal of this project is to understand the human health consequences from exposure to these carboxyalkylating agents. We have made outstanding progress in the first funding cycle, where we have established in detail the carboxymethylation chemistry of DNA, synthesized oligodeoxyribonucleotides harboring site-specifically incorporated carboxymethylated DNA lesions, assessed the formation of the carboxyalkylated DNA lesions in mammalian cells, and investigated how these lesions compromised the efficiency and fidelity of DNA replication in vitro and in cells. In this competitive renewal, we will employ a multi-pronged and innovative approach to investigate how the carboxymethylated DNA lesions compromise the flow of genetic information by altering the efficiency and fidelity of DNA transcription, how the replicative bypass of the carboxyalkylated lesions is modulated by post-translational modifications of translesion synthesis DNA polymerases, and how exposure to carboxyalkylating agents leads to kinome reprogramming in human cells. The outcome of the proposed research will bring our understanding about the human health consequences from exposure to carboxyalkylating agents to a significant new level. In addition, the results of our proposed studies may ultimately lead to the development of new strategies for the prevention and treatment of diabetic complications and gastrointestinal cancers.
Humans are exposed to byproducts of glycolysis and N-nitroso compounds in the gastrointestinal tract, which results in the carboxyalkylation of nucleobases in DNA. The proposed research will reveal the implications of hyperglycemia and exposure to N-nitroso compounds in the etiology of diabetic complications and gastrointestinal tumors. The outcome of the proposed research will ultimately lead to the discovery of novel risk factors for developing these pathological conditions and new targets for treating these diseases.
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