Hexose-6-phosphate dehydrogenase blockade reverses prostate cancer drug resistance in xenograft models by glucocorticoid inactivation.

Jianneng Li, Michael Berk, Mohammad Alyamani, Navin Sabharwal, Christopher Goins, Joseph Alvarado, Mehdi Baratchian, Ziqi Zhu, Shaun Stauffer, Eric A Klein, Nima Sharifi

Science translational medicine 2021 May 26

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Prostate cancer resistance to next-generation hormonal treatment with enzalutamide is a major problem and eventuates into disease lethality. Biologically active glucocorticoids that stimulate glucocorticoid receptor (GR) have an 11β-OH moiety, and resistant tumors exhibit loss of 11β-HSD2, the oxidative (11β-OH → 11-keto) enzyme that normally inactivates glucocorticoids, allowing elevated tumor glucocorticoids to drive resistance by stimulating GR. Here, we show that up-regulation of hexose-6-phosphate dehydrogenase (H6PD) protein occurs in prostate cancer tissues of men treated with enzalutamide, human-derived cell lines, and patient-derived prostate tissues treated ex vivo with enzalutamide. Genetically silencing H6PD blocks NADPH generation, which inhibits the usual reductive directionality of 11β-HSD1, to effectively replace 11β-HSD2 function in human-derived cell line models, suppress the concentration of biologically active glucocorticoids in prostate cancer, and reverse enzalutamide resistance in mouse xenograft models. Similarly, pharmacologic blockade of H6PD with rucaparib normalizes tumor glucocorticoid metabolism in human cell lines and reinstates responsiveness to enzalutamide in mouse xenograft models. Our data show that blockade of H6PD, which is essential for glucocorticoid synthesis in humans, normalizes glucocorticoid metabolism and reverses enzalutamide resistance in mouse xenograft models. We credential H6PD as a pharmacologic vulnerability for treatment of next-generation androgen receptor antagonist-resistant prostate cancer by depleting tumor glucocorticoids. Copyright © 2021 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

Citation

Jianneng Li, Michael Berk, Mohammad Alyamani, Navin Sabharwal, Christopher Goins, Joseph Alvarado, Mehdi Baratchian, Ziqi Zhu, Shaun Stauffer, Eric A Klein, Nima Sharifi. Hexose-6-phosphate dehydrogenase blockade reverses prostate cancer drug resistance in xenograft models by glucocorticoid inactivation. Science translational medicine. 2021 May 26;13(595)