Abstract PO-152: Metabolic rewiring in African-American prostate cancer: A role for adenosine-inosine axis
Authors: Charles Christy 
Published: January 2022

Abstract
African-American (AA) men have a 60% higher incidence of prostate cancer compared to European-American (EA) men and tend to have a more aggressive clinical outcome. An understanding of the altered biological responses and the factors that lead to health disparity in prostate cancer development and progression is unclear. Metabolism defines the physiological state of the cell and metabolic reprogramming is a hallmark of cancer. Thus, studying the metabolic landscape will be critical for understanding the biological changes that might contribute to this disparity. Analysis of 190 metabolites across prostate cancer/benign adjacent tissue pairs from ancestry typed AA and EA men performed in our laboratory, revealed altered levels of adenosine and inosine. High inosine to adenosine ratio is observed in AA men compared to EA men. In line with this finding, the enzyme adenosine deaminase (ADA), which converts adenosine to inosine was found elevated in AA men, potentially explaining the high inosine to adenosine ratio in AA PCa. The effects of these metabolic alterations on AA PCa progression are unknown. The current study will address the knowledge gap on the consequences of elevated ADA activity in AA PCa and attempt to dissect its role in effecting an aggressive phenotype in PCa. To determine the role of elevated ADA in PCa, it was overexpressed in ancestry-typed AA (MDA-PCa-2A) and EA PCa(LNCaP) cell lines (termed ADA OE). Phenotypic examination of these cells revealed increased ADA enzyme activity decreases the cell-ECM adhesion. Molecular analyses revealed a significant reduction in Tenascin C(TNC), a matrix protein known for its anti-adhesive properties. TNC is critical for modulating cell motility and adhesion. TNC is also a marker for the reactive stromal microenvironment. Therefore, we evaluated the effects of altered adenosine-inosine levels on stromal cells. TNC induction was observed in stromal cells upon treatment with ADA OE conditioned media and inosine addition. These molecular findings suggest that high ADA activity could facilitate adhesion decrease and modulate the stromal microenvironment to aid in the metastatic dissemination from the primary tumor. From a translational viewpoint, ADA enzyme activity could serve as a biomarker for metastatic prostate cancer. Therefore, we further look to analyze the inosine to adenosine levels in patient samples and correlate with various clinical outcomes in PCa. Our initial analysis reveals high inosine to adenosine ratio in biopsy positive patient samples compared to biopsy negative samples. Our next steps of analysis include correlating the enzyme activity with (i)Biochemical Recurrence(BCr) (ii)Time to attaining castration resistance in castration-sensitive patients (iii)Time to metastasis (iv)Response to Androgen deprivation in patients after BCr. Based on our current findings, we expect the inosine to adenosine ratio in plasma or urine to serve as a predictive marker for PCa incidence or progression in AA men. In addition, we expect ADA to serve as a potential therapeutic target for AA PCa.
Citation Format: Christy Charles. Metabolic rewiring in African-American prostate cancer: A role for adenosine-inosine axis [abstract]. In: Proceedings of the AACR Virtual Conference: 14th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2021 Oct 6-8. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2022;31(1 Suppl):Abstract nr PO-152.