Fatty Liver & Cancer Risk: Caspase-2 Enzyme Blockers May Backfire

A surprising new study challenges assumptions about treating fatty liver disease, suggesting that blocking a key enzyme intended to protect the liver could, over time, increase the risk of chronic liver damage, and cancer. Published in Science Advances, the research from the University of Adelaide highlights the complex interplay between liver cell stability, genetic material, and the enzyme Caspase-2.

Caspase-2: A Dual Role in Liver Health

For some time, Caspase-2 has been investigated as a potential therapeutic target for fatty liver disease. However, the new findings indicate that inhibiting this enzyme isn’t a straightforward solution. Researchers discovered that losing Caspase-2 leads to abnormal growth in liver cells, triggering a cascade of damaging effects – inflammation, scarring, and a heightened risk of liver cancer. Dr. Loretta Dorstyn, lead researcher from the Centre for Cancer Biology, explains that Caspase-2 is essential for maintaining the genetic stability of liver cells and likewise plays a role in regulating fat levels within the liver.

Liver cells naturally contain multiple copies of genetic material, a state known as polyploidy. This can help the liver cope with stress, but the study demonstrates that without Caspase-2, abnormally high levels of polyploidy develop into detrimental. “Our study shows that without the enzyme Caspase-2, abnormally high levels of polyploidy in the liver can be damaging,” Dr. Dorstyn said.

Mouse Models Reveal Long-Term Risks

To explore this connection, the researchers utilized genetically modified mice. Those lacking the Caspase-2 enzyme, or with a non-functional version of it, developed abnormally large liver cells exhibiting significant genetic and cellular damage. This damage progressed over time, leading to chronic liver inflammation and characteristics resembling hepatitis-like liver disease, including scarring and oxidative damage. Critically, these mice were significantly more likely to develop liver cancer as they aged.

The incidence of liver cancer in older mice without functional Caspase-2 was up to four times higher than in normal mice, specifically exhibiting hepatocellular carcinoma, the most common type of liver cancer. This finding overturns the previous assumption that inhibiting Caspase-2 is universally beneficial. According to the study, while inhibiting the enzyme might offer short-term benefits, such as reducing fatty liver disease, its long-term loss is demonstrably harmful.

“Without it, these cells accumulate, and can become cancerous, while also creating an environment that predisposes the liver to cancer,” Dr. Dorstyn explained. The research suggests Caspase-2 is crucial for removing damaged and abnormal liver cells as we age.

Implications for Treatment Strategies

Professor Sharad Kumar, senior author of the study, emphasized the importance of these findings for future therapies. “There has been significant interest in targeting Caspase-2 to treat metabolic liver disease and reduce liver cancer risk,” Prof Kumar said. “Our data shows that this approach could have serious unintended consequences later in life, increasing susceptibility to chronic liver inflammation, fibrosis and cancer.”

This caution is particularly relevant given the rising global prevalence of liver disease. Driven by factors like aging populations, obesity, and metabolic conditions, liver cancer is a significant public health concern. In 2022, the World Cancer Research Fund reported nearly 760,000 deaths worldwide from liver cancer, making it the sixth most common cancer globally. ScienceDaily reports on the study’s implications for current and future treatments.

Understanding Polyploidy and Liver Disease

The concept of polyploidy – having extra copies of genetic material – is central to this research. While often helpful for the liver to manage stress, uncontrolled polyploidy, especially in the absence of Caspase-2, appears to contribute to cellular damage and cancer development. The study highlights the delicate balance required for maintaining liver cell health and the potential risks of disrupting this balance through targeted therapies.

What’s Next for Liver Cancer Research?

The Adelaide University team’s findings underscore the necessitate for a more nuanced understanding of Caspase-2’s role in liver disease. Further research is crucial to determine whether the results observed in mouse models translate to humans. The researchers suggest that future studies should focus on identifying biomarkers that can predict an individual’s risk of developing liver cancer following Caspase-2 inhibition. The University of Adelaide notes that the study’s publication in Science Advances marks a significant step forward in understanding the complexities of liver disease.

Professor Kumar indicated that ongoing investigations will explore alternative therapeutic strategies that can address fatty liver disease without compromising long-term liver health. This includes examining other potential drug targets and lifestyle interventions. The findings also highlight the importance of long-term monitoring of patients undergoing Caspase-2 inhibitor therapy to detect any early signs of liver damage or cancer development. EurekAlert! provides additional details on the research and its potential impact.

For individuals concerned about liver health, maintaining a healthy lifestyle – including a balanced diet, regular exercise, and avoiding excessive alcohol consumption – remains the cornerstone of prevention. Anyone experiencing symptoms of liver disease, such as fatigue, jaundice, or abdominal pain, should consult with a qualified healthcare professional for proper diagnosis and management.