Identification of metabolic adducts associated with prostate cancer progression in African American men

Abstract Prostate cancer (PCa) is the second highest cause of cancer-related deaths in men. African American/Black (AA/B) men are disproportionally impacted by PCa with a 60% higher incidence of disease and a 2-3x fold increase in mortality risk compared to European American (EA) men. There is an urgent need to identify the

underlying biological changes that give rise to this disparity to develop inclusive diagnostic and predictive tests and tailored therapeutic treatments. A myriad of causes for the biological changes that drive PCa health disparities have been proposed, including socioeconomic, genetic, and environmental factors. These factors all

give rise to altered metabolism, a biological change associated with PCa onset and progression. A proposed mechanism for how these changes drive PCa is through the production of the reactive electrophile methylglyoxal (MG). MG is a by-product of lipid, protein, and sugar metabolism and forms covalent adducts on DNA, RNA, and

protein. These adducts, termed MG-advanced glycation end products (MG-AGEs) lead to DNA mutations and genomic instability, change RNA stability and translation, and alter protein stability and function. In addition, MG- AGEs bind and activate the receptor for AGEs (RAGE). To regulate MG and MG-AGEs, cells use glyoxalase 1

(GLO1) to detoxify MG and soluble RAGE (sRAGE) to sequester MG-AGEs and prevent RAGE activation. These components are termed the AGE/RAGE axis. Our long-term goal is to define the role of MG-AGEs and the AGE/RAGE axis as biomarkers and drivers of PCa and determine how racial disparities influence this process.

To define the association of MG-AGEs, GLO1, RAGE, and sRAGE with PCa health disparities, we designed a nested case-control trial of AA/B and EA men with and without PCa. We measured serum MG-AGEs using mass spectrometry, serum sRAGE using ELISA, and sequenced the GLO1 and AGER (gene encoding RAGE) loci in

genomic DNA isolated from whole blood. We discovered that MG-AGEs, sRAGE, and GLO1 and AGER SNPs were significantly associated with PCa in AA/B men but not EA men. We also observed a significant difference between these components in AA/B and EA men without PCa. This led us to hypothesize that MG-AGEs,

sRAGE, and GLO1 and AGER SNPs may have utility as biomarkers for PCa in AA/B men and that GLO1 SNPs may play a role in the accumulation of MG-AGEs, mutations, and PCa cell growth. To test this hypothesis, we propose to 1) use molecular and genetic features of the AGE/RAGE axis along with demographic and clinical

variables to predict the risk of PCa in AA/B and EA men using a multivariable clinical-genetic risk model and 2) use cell lines derived from AA/B and EA PCa tumors to determine the impact of GLO1 SNPs on MG-AGE accumulation, cell growth, the expression of metastatic markers, and the induction of genomic mutations. This

work represents the first analysis of MG-AGEs in AA/B and EA men with PCA, utilizes novel mass spectrometry methods, and describes generation of cell lines expressing GLO1 polymorphisms from diverse racial groups.