Biochemical Pharmacology 226 (2024) 116385 Available online 21 June 2024 0006-2952/© 2024 Elsevier Inc. All rights are reserved, including those for text and data mining, AI training, and similar technologies. Androgen deprivation-induced senescence confers sensitivity to a senolytic strategy in prostate cancer Valerie Carpenter a, b , Tareq Saleh c , Eesha Chakraborty a , So Min Lee a , Graeme Murray d , Jason Reed d, e , Andrew Souers f , Anthony C. Faber e, g , Hisashi Harada e, g , David A. Gewirtz a, e, * a Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, Richmond, VA 23298, USA b Cancer and Cell Biology Division, Translational Genomics Research Institute, Phoenix, AZ, USA c Department of Pharmacology and Public Health, Faculty of Medicine, The Hashemite University, Zarqa 13133, Jordan d Department of Physics, Virginia Commonwealth University, Richmond, VA, USA e Massey Comprehensive Cancer Center, Virginia Commonwealth University, Richmond, VA, USA f AbbVie, 1 North Waukegan Road, North Chicago, IL, USA g Philips Institute for Oral Health Research, School of Dentistry, Virginia Commonwealth University, Richmond, VA 23298, USA A R T I C L E INFO Keywords: Androgen-deprivation Castration-resistance ABT-263 Prostate cancer Senescence Senolytic ABSTRACT We have previously demonstrated that androgen-dependent prostate cancer (PCa) cell lines enter a state of senescence following exposure to androgen deprivation therapies (ADT). ADT-induced senescence was found to be transient, as senescent cells develop castration resistance and re-emerge into a proliferative state even under continuous androgen deprivation in vitro. Moreover, the BCL-X L /BCL-2 inhibitor, ABT-263 (navitoclax), an established senolytic agent, promoted apoptosis of senescent PCa cells, suppressing proliferative recovery and subsequent tumor cell outgrowth. As this strategy has not previously been validated in vivo, we used a clinically relevant, syngeneic murine model of PCa, where mice were either castrated or castrated followed by the administration of ABT-263. Our results largely confirm the outcomes previously reported in vitro; specifically, castration alone results in a transient tumor growth suppression with characteristics of senescence, which is prolonged by exposure to ABT-263. Most critically, mice that underwent castration followed by ABT-263 experienced a statistically significant prolongation in survival, with an increase of 14.5 days in median sur- vival time (56 days castration alone vs. 70.5 days castration + ABT-263). However, as is often the case in studies combining the promotion of senescence with a senolytic (the “one-two” punch approach), the suppression of tumor growth by the inclusion of the senolytic agent was transient, allowing for tumor regrowth once the drug treatment was terminated. Nevertheless, the results of this work suggest that the “one-two” punch senolytic strategy in PCa may effectively interfere with, diminish, or delay the development of the lethal castration- resistant phenotype. 1. Introduction There is now an extensive body of literature that supports the ca- pacity of the BCL-X L /BCL-2 inhibitor, ABT-263 (navitoclax), to serve as a senolytic agent in multiple tumor models when administered subsequent to chemotherapy or ionizing radiation [1–4]. However, few studies have actually demonstrated prolongation of animal survival via this strategy. As an example from our own work, we showed that human breast cancer and non-small cell lung cancer cell lines undergo Therapy-Induced Senescence (TIS) in response to doxorubicin or etoposide, respectively, and that this response confers sensitivity to BCL-X L inhibition [5]. In vivo, the administration of ABT-263 following doxorubicin or etoposide resulted in increased tumor apoptosis and delayed tumor growth; however, these studies were not sufficiently prolonged to assess whether this combinational treatment promoted animal survival [5]. Further- more, this work was obligatorily performed in immunodeficient tumor- bearing animal models [5]. In a study of murine head and neck tumor cells induced into senescence by cisplatin in an immunocompetent DOI of original article: https://doi.org/10.1016/j.bcp.2021.114765. Abbreviations: PCa, Prostate Cancer; ADT, Androgen Deprivation Therapy; SA-β-gal, Senescence-Associated-β-Galactosidase; TIS, Therapy-Induced Senescence. * Corresponding author at: Massey Comprehensive Cancer Center, Virginia Commonwealth University, 401 College St., Richmond, VA 23298, USA. E-mail address: david.gewirtz@vcuhealth.org (D.A. Gewirtz). Contents lists available at ScienceDirect Biochemical Pharmacology journal homepage: www.elsevier.com/locate/biochempharm https://doi.org/10.1016/j.bcp.2024.116385 Received 19 March 2024; Received in revised form 17 June 2024; Accepted 20 June 2024