Exercise prevents onset of liver cancer in high-risk mice
Liver cancer rates have more than tripled since 1980, according to the American Cancer Society, and a rise in obesity and type 2 diabetes have played a significant role in this trend. Scientists investigating these links in mice have uncovered new evidence of the importance of exercise in keeping these conditions at bay, finding that it likely prevents early onset of liver cancer in high-risk individuals.
The benefits of regular exercise in maintaining health and wellbeing are well known, and recent research has pointed to the role it can play in preventing or even combating cancer. The new study conducted by researchers at the Australian National University (ANU) sought to dive a little deeper into this, and if exercise could prevent liver cancer in those already at high risk.
“We know exercise helps reduce rates of some cancers already but we wanted to find out if exercise would reduce liver cancer rates when there is a high risk of developing it,” says ANU’s Professor Farrell. “For example, if you have had or have hepatitis C, cirrhosis and you're a type 2 diabetic you have really a very high rate of liver cancer.”
Specifically, the team studied how fatty liver disease linked to obesity and type 2 diabetes can act as a precursor to liver cancer, and how exercise could break this chain of negative health outcomes. Mice were engineered to over-eat in order to develop obesity and type 2 diabetes, with the rodents then injected with cancer-causing agents early in life.
Half of these mice were given a running wheel and the other half were not, condemning them to a sedentary existence. The active mice ran up to 40 km (25 mi) a day, which slowed down their weight gain somewhat. While they did still go on to develop obesity after six months, they were in far better health than the sedentary group of mice.
“Nearly all the mice that did not exercise developed cancer within six months,” says Professor Farrell. “Among the mice that exercised none developed liver cancer in six months, showing that exercise prevented early onset of liver cancer.”
The scientists observed a reduction in the severity of fatty liver disease in the mice that exercised, along with a reduction in activity of a stress-related signaling molecule called JNK1. This molecular pathway is thought to play a role in altering liver cells as they develop into cancers, and the study suggests that it could be switched off via regular exercise.
“We now have some robust evidence to show exercise will help – especially for those who are overweight with type 2 diabetes,” says Professor Farrell. “We also started to unravel some of the molecular pathways involved, and the benefit of that is that we can design drugs to interrupt those pathways.”
The research was published in the Journal of Hepatology.