Stress before cancer therapy could help deadly cells survive treatment, lead to disease recurrence

Patients who experience physical or psychological stress – including rigorous exercise – one or two days before a cancer treatment might be unknowingly sabotaging their therapy, new research suggests.

Stress in the body – even physical stress caused by intense exercise – activates a stress-sensitive protein that can spark a series of events that allow cancer cells to survive such treatments as chemotherapy and radiation, according to the research.

Though the study involved a series of experiments in breast cancer cell cultures, the researchers say the findings are a clear indication that cancer cells have found a way to adapt and resist treatment with the help of this stress-inducible protein.

This cancer cell survival can be traced to the presence of heat shock factor-1, which previous research has linked to stress. Ohio State University researchers first noticed that this common protein can help heart tissue survive in a toxic environment, leading the scientists to suspect that in cancer, this phenomenon could have serious consequences.

A series of experiments using breast cancer cells showed that a protein activated by the presence of heat shock factor-1 could block the process that kills cancer cells even after the cells' DNA was damaged by radiation. The same was true when the cells were subjected to a common chemotherapy drug.

The researchers hope to develop a drug that could suppress heat shock factor-1 as a supplement to cancer therapy, but in the meantime, they recommend that patients avoid both psychological and physical stress in the days leading up to a cancer treatment.

"One of the known inducers of this factor is exercise. I am not against exercise, but the timing is critical. It looks like any intense or prolonged physical activity a couple of days before the start of cancer therapy is highly risky, and has potential to reduce the benefits of the treatment," said Govindasamy Ilangovan, lead author of the study and associate professor of internal medicine at Ohio State.

The study appears online in the journal Molecular Cancer Research.

Ilangovan, an investigator in Ohio State's Davis Heart and Lung Research Institute, specializes in cardiovascular medicine. But when he observed in previous research that this stress-inducible protein could salvage heart cells that otherwise were doomed to die, he collaborated with radiology specialists to test the protein's effects in cancer.

While he used breast cancer cells for this study, he suspects that the widespread presence of heat shock factor-1 in the body means the protein could have this same effect on any kind of adenocarcinoma, a class of cancer cells that originate in a gland.

Heat shock factor-1 activates a specific protein, known as Hsp27, that ends up helping the cancer cells survive, Ilangovan said.