Loss of PDE4D7 expression promotes androgen independence, neuroendocrine differentiation, and alterations in DNA repair: implications for therapeutic strategies

Gulliver, C., Huss, S., Semjonow, A., Baillie, G. S. and Hoffmann, R. (2023) Loss of PDE4D7 expression promotes androgen independence, neuroendocrine differentiation, and alterations in DNA repair: implications for therapeutic strategies. British Journal of Cancer, (doi: 10.1038/s41416-023-02417-5) (PMID:37740039) (Early Online Publication)

Abstract

Background: Androgen signalling remains the seminal therapeutic approach for the management of advanced prostate cancer. However, most tumours eventually shift towards an aggressive phenotype, characterised by androgen independence and treatment resistance. The cyclic adenosine monophosphate (cAMP) pathway plays a crucial role in regulating various cellular processes, with the phosphodiesterase PDE4D7 being a vital modulator of cAMP signalling in prostate cancer cells. Methods: Using shRNA-mediated PDE4D7 knockdown in LNCaP cells and downstream analysis via RNA sequencing and phenotypic assays, we replicate clinical observations that diminished PDE4D7 expression promotes an aggressive prostate cancer phenotype. Results: Our study provides evidence that loss of PDE4D7 expression represents a pivotal switch driving the transition from an androgen-sensitive state to hormone unresponsiveness and neuroendocrine differentiation. In addition, we demonstrate that PDE4D7 loss affects DNA repair pathways, conferring resistance to poly ADP ribose polymerase (PARP) inhibitors. Conclusion: Reinstating PDE4D7 expression sensitises prostate cancer cells to anti-androgens, DNA damage response inhibitors, and cytotoxic therapies. These findings provide significant insight into the regulatory role of PDE4D7 in the development of lethal prostate cancer and the potential of its modulation as a novel therapeutic strategy.

• Item Type: Articles
• Keywords: Phosphodiesterase, prostate cancer, risk stratification, prognosis, molecular biomarkers, therapy resistance, castration resistance, DNA repair, neuroendocrine differentiation.
• Status: Early Online Publication
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Gulliver, Chloe and Baillie, Professor George and Hoffmann, Dr Ralf
• Authors: Gulliver, C., Huss, S., Semjonow, A., Baillie, G. S., and Hoffmann, R.
• College/School: College of Medical Veterinary and Life Sciences; College of Medical Veterinary and Life Sciences > School of Cardiovascular & Metabolic Health
• Journal Name: British Journal of Cancer
• Publisher: Nature Publishing Group
• ISSN: 0007-0920
• ISSN (Online): 1532-1827
• Published Online: 22 September 2023
• Copyright Holders: Copyright © The Author(s) 2023
• First Published: First published in British Journal of Cancer 2023
• Publisher Policy: Reproduced under a Creative Commons license