Validating novel inhibitors of hepatic 5β-reductase for the treatment of hepatocellular carcinoma
Nikolaos Nikolaou, University of Oxford
Non-alcoholic fatty liver disease (NAFLD) is the hepatic manifestation of metabolic syndrome. It is a spectrum of disease ranging from simple hepatic lipid storage, eventually progressing to cirrhosis and hepatocellular carcinoma (HCC). 5β-reductase (5βR) is highly expressed in human liver catalysing a fundamental step in bile acid (BA) synthesis. BAs as well as their intermediary products (oxysterols) are established as potent regulators of metabolic and proliferative phenotype, and my recent findings have revealed that genetic silencing of 5βR enhances insulin sensitivity, delays cell cycle progression and decreases proliferation in liver cell lines (doi: 10.1530/endoabs.65.OC1.4). However, no specific 5βR inhibitors are currently available.
In collaboration with the European Lead Factory (ELF), an international consortium of 30 academic/industrial partners (https://www.europeanleadfactory.eu), we have identified novel molecules acting as potent 5βR inhibitors. These compounds have been optimised in liver cell lines, and further validation in primary human hepatocytes is now warranted to fully investigate their potency and potential cytotoxicity in vitro.
Primary human hepatocytes were to be isolated from healthy liver tissue resection surplus from patients undergoing surgery. However, due to the COVID-19 pandemic, clinical research has been suspended, severely impacting our work. With this grant, I request money to purchase primary human hepatocytes and associated consumables, which will enable me to complete this project.
I would like to thank the Bioscientifica Trust for this grant, which enabled me to validate novel hepatic 5β- reductase inhibitors as future therapeutics for the treatment of hepatocellular carcinoma.
Over the last eight years, my work has been focused on the role of 5β-reductase as a potential target for the treatment of non-alcoholic fatty liver disease and its related hepatocellular carcinoma. In collaboration with the European Lead Factory, an international consortium of academic and industrial partners, we identified previously uncharacterised compounds, which could serve as novel pharmaceutical 5β-reductase inhibitors. With the help of Bioscientifica Trust, we purchased primary human hepatocytes and associated consumables to investigate cytotoxicity and validate the potency of these drugs in vitro.
My results showed that, out of 50 hit-lead drugs in total, three compounds caused the least cytotoxicity over increasing drug concentrations. These three compounds were subsequently tested for their ability to inhibit 5β-reductase activity, using pregnanediol glucuronide (PDG, 5β-reductase product) as an endpoint readout measurement. My experiments revealed that all three compounds caused a >70% reduction in PDG formation following 24h of progesterone (5β-reductase substrate) treatment, demonstrating, in total, their potential as novel 5β-reductase inhibitors.
Having validated their potency, additional experiments were performed to investigate whether these drugs could also have an effect on hepatocellular proliferation. My results showed cell cycle arrest and decreased cell proliferation following treatment of human hepatocytes with all three compounds, confirming our hypothesis regarding the beneficial role of 5β-reductase inhibition in hepatocellular carcinoma progression.
The results from this work have already been presented nationally as a poster presentation (SfE-BES 2021) (doi: 10.1530/endoabs.77.P43), and they will be included in an upcoming manuscript currently in preparation. Importantly, these experiments provided me the opportunity to get exposed to new cell models and techniques, crucial for my personal development as an early-career scientist.
Grant awarded: £4,970.91