Cysteine depletion sensitizes prostate cancer cells to agents that enhance DNA damage and to immune checkpoint inhibition

Journal of Experimental & Clinical Cancer Research

Research

George Georgiou¹  Everett Stone²  Austin Kindall³  Achinto Saha³  Shengyuan Zhao³  Carly Wilder³  Chelsea A. Friedman³  Rachel Clark³  John DiGiovanni⁴  Dawit Kidane⁵ 

[1] Department of Chemical Engineering, The University of Texas at Austin, 78712, Austin, TX, USA;Department of Molecular Biosciences, The University of Texas at Austin, 78712, Austin, TX, USA;Institute for Cellular and Molecular Biology, The University of Texas at Austin, 78712, Austin, TX, USA;Department of Molecular Biosciences, The University of Texas at Austin, 78712, Austin, TX, USA;Institute for Cellular and Molecular Biology, The University of Texas at Austin, 78712, Austin, TX, USA;Division of Pharmacology and Toxicology and Dell Pediatric Research Institute, The University of Texas at Austin, 1400 Barbara Jordan Blvd, 78723, Austin, TX, USA;Division of Pharmacology and Toxicology and Dell Pediatric Research Institute, The University of Texas at Austin, 1400 Barbara Jordan Blvd, 78723, Austin, TX, USA;Center for Molecular Carcinogenesis and Toxicology, The University of Texas at Austin, 78712, Austin, TX, USA;LiveSTRONG Cancer Institutes, Dell Medical School, The University of Texas at Austin, 78712, Austin, TX, USA;Division of Pharmacology and Toxicology and Dell Pediatric Research Institute, The University of Texas at Austin, 1400 Barbara Jordan Blvd, 78723, Austin, TX, USA;Center for Molecular Carcinogenesis and Toxicology, The University of Texas at Austin, 78712, Austin, TX, USA;LiveSTRONG Cancer Institutes, Dell Medical School, The University of Texas at Austin, 78712, Austin, TX, USA;Department of Phyisiology & Biophysics, College of Medicine, Howard University, 520 W Street, NW, 20059, Washington, DC, USA;

关键词: Prostate cancer;    Reactive Oxygen Species;    DNA damage;    Combination therapy;    Immune checkpoint inhibitor;   

DOI  :  10.1186/s13046-023-02677-2

 received in 2023-01-12, accepted in 2023-04-19,  发布年份 2023

来源: Springer

【 摘 要 】

BackgroundProstate Cancer (PCa) represents one of the most commonly diagnosed neoplasms in men and is associated with significant morbidity and mortality. Therapy resistance and significant side effects of current treatment strategies indicate the need for more effective agents to treat both androgen-dependent and androgen-independent PCa. In earlier studies, we demonstrated that depletion of L-cysteine/cystine with an engineered human enzyme, Cyst(e)inase, increased intracellular ROS levels and inhibited PCa growth in vitro and in vivo. The current study was conducted to further explore the mechanisms and potential combinatorial approaches with Cyst(e)inase for treatment of PCa.MethodsDNA single strand breaks and clustered oxidative DNA damage were evaluated by alkaline comet assay and pulsed field gel electrophoresis, respectively. Neutral comet assay and immunofluorescence staining was used to measure DNA double strand breaks. Cell survival and reactive oxygen species level were measured by crystal violet assay and DCFDA staining, respectively. Western blot was used to determine protein expression. FACS analyses were preformed for immune cell phenotyping. Allograft and xenograft tumor models were used for assessing effects on tumor growth.ResultsPCa cells treated with Cyst(e)inase lead to DNA single and double strand breaks resulted from clustered oxidative DNA damage (SSBs and DSBs). Cyst(e)inase in combination with Auranofin, a thioredoxin reductase inhibitor, further increased intracellular ROS and DNA DSBs and synergistically inhibited PCa cell growth in vitro and in vivo. A combination of Cyst(e)inase with a PARP inhibitor (Olaparib) also increased DNA DSBs and synergistically inhibited PCa cell growth in vitro and in vivo without additional ROS induction. Knockdown of BRCA2 in PCa cells increased DSBs and enhanced sensitivity to Cyst(e)inase. Finally, Cyst(e)inase treatment altered tumor immune infiltrates and PD-L1 expression and sensitized PCa cells to anti-PD-L1 treatment.ConclusionsThe current results demonstrate the importance of oxidative DNA damage either alone or in combination for Cyst(e)inase-induced anticancer activity. Furthermore, cysteine/cystine depletion alters the tumor immune landscape favoring enhanced immune checkpoint inhibition targeting PD-L1. Thus, combinatorial approaches with Cyst(e)inase could lead to novel therapeutic strategies for PCa.

【 授权许可】

CC BY   
© The Author(s) 2023

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