Pharmacological Inhibition of Endogenous Hydrogen Sulfide Production Slows Bladder Cancer Progression in an Intravesical Murine Model

Sydney Relouw; George J Dugbartey; Patrick McLeod; Natasha N Knier; Francisco Martinez Santiesteban; Paula J Foster; Heather-Anne Cadieux-Pitre; Nicole M Hague; Jenna Caine; Kaitlin Belletti; Sally Major; Caroline O'Neil; Manal Y Gabril; Madeleine Moussa; Melissa J Huynh; S M Mansour Haeryfar; Alp Sener

doi:10.3390/ph17091212

Pharmacological Inhibition of Endogenous Hydrogen Sulfide Production Slows Bladder Cancer Progression in an Intravesical Murine Model

Pharmaceuticals (Basel). 2024 Sep 14;17(9):1212. doi: 10.3390/ph17091212.

Authors

Sydney Relouw^{1

2}, George J Dugbartey^{2

3

4

5}, Patrick McLeod², Natasha N Knier^{6

7}, Francisco Martinez Santiesteban⁶, Paula J Foster^{6

7}, Heather-Anne Cadieux-Pitre⁸, Nicole M Hague⁸, Jenna Caine⁸, Kaitlin Belletti⁸, Sally Major^{2

8}, Caroline O'Neil⁷, Manal Y Gabril⁹, Madeleine Moussa⁹, Melissa J Huynh^{3

10}, S M Mansour Haeryfar^{1

6

10

11

12}, Alp Sener^{1

2

3

10}

Affiliations

¹ Department of Microbiology & Immunology, Western University, London, ON N6A 5C1, Canada.
² Matthew Mailing Center for Translational Transplant Studies, Western University, London Health Sciences Center, London, ON N6A 5A5, Canada.
³ Department of Surgery, Western University, London, ON N6A 5C1, Canada.
⁴ Department of Pharmacology & Toxicology, School of Pharmacy, College of Health Sciences, University of Ghana, Legon, Accra P.O. Box LG43, Ghana.
⁵ Department of Physiology & Pharmacology, Accra College of Medicine, East Legon, Accra P.O. Box CT9828, Ghana.
⁶ Department of Medical Biophysics, Western University, London, ON N6A 5C1, Canada.
⁷ Robarts Research Institute, Western University, London, ON N6A 3K7, Canada.
⁸ Department of Animal Care & Veterinary Services, Western University, London, ON N6A 5C1, Canada.
⁹ Department of Pathology and Laboratory Medicine, Western University, London, ON N6A 5C1, Canada.
¹⁰ Lawson Health Research Institute, London, ON N6C 2R5, Canada.
¹¹ Department of Medicine, Division of Clinical Immunology & Allergy, Western University, London, ON N6A 5C1, Canada.
¹² Department of Oncology, Western University, London, ON N6A 5C1, Canada.

Abstract

Present bladder cancer therapies have relatively limited therapeutic impact and account for one of the highest lifetime treatment costs per patient. Therefore, there is an urgent need to explore novel and optimized treatment strategies. The present study investigated the effects of inhibiting endogenous hydrogen sulfide (H₂S) production on bladder cell viability and in vivo tumor progression. We targeted the H₂S-producing enzyme, cystathionine γ-lyase, in 5637 cells using propargylglycine (H₂S inhibitor) and performed cytofluorimetric analysis to evaluate cell viability. We then tested the efficacy of propargylglycine alone or in combination with gemcitabine (conventional chemotherapy) in an intravesical murine model of bladder cancer. Magnetic resonance imaging and immunohistochemical staining for cell proliferation, apoptosis, immune-cell infiltration, and neovascularization were performed to evaluate tumor response. Compared to control conditions or cohorts, propargylglycine administration significantly attenuated bladder cancer cell viability in vitro (p < 0.0001) and tumor growth (p < 0.002) and invasion in vivo. Furthermore, propargylglycine enhanced the anti-cancer effects of gemcitabine, resulting in tumor regression (p < 0.0001). Moreover, propargylglycine induced cleaved PARP-1-activated apoptosis (p < 0.05), as well as intratumoral CD8⁺ T cell (p < 0.05) and F4/80⁺ macrophage (p < 0.002) infiltration. Propargylglycine also reduced intratumoral neovascularization (p < 0.0001) and cell proliferation (p < 0.0002). Importantly, the pro-apoptotic and anti-neovascularization effects of gemcitabine were enhanced by propargylglycine co-administration. Our findings suggest that inhibition of endogenous H₂S production can be protective against bladder cancer by enhancing the chemotherapeutic action of gemcitabine and may be a novel pharmacological target and approach for improved bladder cancer diagnosis and treatments in the future.

Keywords: apoptosis; bladder cancer (BC); cystathionine γ-lyase (CSE); gemcitabine; hydrogen sulfide (H2S); intravesical administration; magnetic resonance imaging; propargylglycine (PAG); tumor progression.

Grants and funding

This work was supported by the Canadian Urological Association Scholarship Fund by the Canadian Urological Association and the Department of Surgery Internal Research Grant by the Department of Surgery, Schulich School of Medicine and Dentistry, Western University.