Link between excessive heart muscle and cancer growth

Link between excessive heart muscle and cancer growth

High blood pressure, also known as hypertension, can cause the heart muscle to work harder, resulting in the expansion of heart cells, which causes the walls of the heart to thicken. The condition, known as cardiac hypertrophy, can lead to heart failure if not stopped. Symptoms of cardiac hypertrophy can include shortness of breath, fatigue, fainting, and chest pain.

 Researchers have identified molecular ties between the growth of cancer cells and heart cells that suggest existing cancer drugs may be able to help those with enlarged heart cells -- a condition that can lead to heart attacks and stroke.

The group of enzymes targeted in this study are known as class 1 histone deacetylases (HDACs), which help regulate the replication and repair of DNA. HDACs can spur the growth of cancer cells. Drugs that inhibit this ability halt or slow the spread of cancer cells.

In this study, researchers unraveled the molecular processes at work behind the scenes of those processes, and found that suppressing HDACs also suppressed the activity of a critical molecule called mTOR (mechanistic target of rapamycin), which regulates the growth of cells. Mice that had been genetically altered to shut off HDAC activity reduced mTOR activity and slowed the enlargement of cardiac muscle cells. The work went on to decipher the molecular circuitry linking HDAC activity and mTOR.

"HDAC inhibitors are approved to treat various cancers, and our results suggest how these drugs might work when repurposed to prevent heart failure," said lead author. 

"In some cells, disruption of a molecular pathway can lead to cancer, whereas perturbations of that same pathway in heart cells can lead to heart failure. Thus, there are interesting and sometimes surprising commonalities across the biologies of cancer and heart disease," said the senior author.

The work also adds to a growing understanding that epigenetic mechanisms, which are external factors that govern DNA expression, are a fruitful area of research for heart disease.