Design, Synthesis, and Efficacy of Novel Trojan Horse Compounds Targeting Metabolic Vulnerabilities in Prostate Cancer
Authors: Edgerton L Bogue , Hayball E F , O’Connell F , Ward MP , O’Toole S , Martin CM , Selemidis S , Brooks RD , Tewari P , Brooks DA , O’Leary JJ 
Published: August 2024

AbstractBackground and purposeProstate cancer (PCa) remains a significant global health concern, warranting the development of new therapeutic strategies.1Metabolic reprogramming, an emerging hallmark of PCa progression characterized by aberrant nutrient utilization, has become a focus area in developing new treatments. Among these metabolic alterations, the Warburg effect—a shift towards aerobic glycolysis— has garnered significant attention as a potential therapeutic target.2To explore this, we synthesised a novel class of Trojan Horse compounds designed to exploit the unique metabolic profile of cancer cells and investigated their therapeutic potential using cell based models of PCa, as a proof of principle strategy.Experimental approachPreliminary cytotoxicity analysis revealed that native menadione had low efficacy against PCa cells. Consequently, we developed glucose and fatty acid conjugated TH compounds based on a menadione backbone. A library of six novel menadione-glucose and fatty acid-based TH compounds were synthesized through copper-catalysed click chemistry. These compounds were designed to mimic a desirable fuel source (sugar or fatty acid) acting as a “Trojan Horse” for PCa cells to modulate their metabolism. The cytotoxic and selective effects of the TH compounds were evaluated in PCa and non-malignant cell lines cultured under varying glucose conditions. To elucidate the mechanisms of action, mitochondrial bioenergetics, metabolic phenotyping, and metabolomic profiling were employed to assess the impact of each TH compound on cellular metabolism.Key resultsTH3 (glucose) and TH5 (fatty acid) compounds demonstrated promising cytotoxicity for PCa cell lines, with TH5 exhibiting superior selectivity compared to TH3 and particularly over native menadione. Despite these results, alterations in metabolic phenotypes were only modest. Mitochondrial bioenergetics were notably impacted by TH5, while ROS levels remained stable post-treatment, likely due to an increase in ROS scavenging amino acids as a compensatory antioxidant response.Conclusion and ImplicationsThis study demonstrates the potential of employing glucose and fatty acid-conjugated compounds to target the unique metabolic features of PCa. These findings offer promising new avenues for further investigation, aimed at optimizing efficacy and selectivity of these compounds for clinical translation. The intricate relationship between ROS production and antioxidant defence mechanisms emphasizes the complex nature of metabolic interventions in cancer. Elucidating the mode of action and exploring molecular modifications may pave the way for personalised and targeted PCa therapies, ultimately improving patient outcomes and mitigating the global burden of this disease.Significance statementThis body of work gives critical insights into the metabolic vulnerabilities of prostate cancer (PCa), particularly of androgen-independent and metastatic disease, which currently present significant treatment challenges. By designing, synthesising and testing innovative menadione-based ‘Trojan Horse’ compounds that target altered cancer cell metabolism, this research highlights a promising new therapeutic strategy against malignant cells. The findings underscore the potential for metabolic reprogramming to combat treatment resistance in advanced PCa, paving the way forward for the development of new drugs and personalised treatment approaches. This could lead to improved outcomes for patients with currently untreatable forms of the disease.