Abstract C062: Metabolic rewiring: A role for adenosine-inosine axis in African-American prostate cancer
Authors: Charles Christy 
Published: January 2023

Abstract
African-American (AA) men have a 60% higher incidence of prostate cancer (PCa) compared to European-American (EA) men. An understanding of the altered biological responses and the factors that lead to health disparity in PCa 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 crucial for understanding the biological changes that might contribute to this disparity. Analysis of 190 metabolites across PCa/benign adjacent tissue pairs from ancestry typed AA and EA men done in our laboratory, revealed altered levels of nucleosides adenosine and inosine. High inosine to adenosine ratio was observed in AA men compared to EA men. In line with this, 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 consequences of the accumulation of these metabolites on AA PCa progression are unknown. This study will address the knowledge gap on the effects adenosine-inosine alterations 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 AA(MDA-PCa-2A) and EA PCa (LNCaP) cell lines (termed ADA OE). Phenotypic examination of these cells revealed high ADA enzyme activity decreases the cell-ECM adhesion. Molecular analyses revealed that upon ADA OE there is a reduction in Tenascin C(TNC), a matrix protein known for its anti-adhesive properties. TNC-rich microenvironment facilitates reactive stromal induction and high motility. This TNC-mediated reprogramming enhances the metastatic ability and PCa progression in bone. TNC induction was observed in stromal cells (DPT44) upon treatment with ADA OE conditioned media and inosine addition. PCa progression on bone was assessed using a cancer cell-bone in vitro co-culture system. High inosine and adenosine levels enabled better attachment of PCa cells to the bone. These findings suggest that an altered adenosine/inosine axis could facilitate adhesion decrease and modulate the stromal microenvironment to aid in the metastatic dissemination and migration towards the bone. Adenosine-inosine alterations could serve as a biomarker for metastatic PCa. We will further analyze the inosine and adenosine levels in patient samples and correlate them with various clinical outcomes in PCa. Our study so far shows high inosine to adenosine ratio in biopsy positive patient samples compared to biopsy negative samples. Our next steps of analysis include correlating the metabolite levels with (i)Biochemical recurrence (BCr) (ii)Time to attaining castration resistance (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, the enzyme ADA could serve as a potential therapeutic target for AA PCa.
Citation Format: Christy Charles. Metabolic rewiring: A role for adenosine-inosine axis in African-American prostate cancer [abstract]. In: Proceedings of the 15th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2022 Sep 16-19; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2022;31(1 Suppl):Abstract nr C062.