Nerves play key role in triggering prostate cancer

Scientists have found that nerves play a critical role in both the development and spread of prostate tumours.
The findings, by researchers at Albert Einstein College of Medicine of Yeshiva University in US, using both a mouse model and human prostate tissue, may lead to new ways to predict the aggressiveness of prostate cancer and to novel therapies for preventing and treating the disease.
The study was led by stem-cell expert Paul Frenette, professor of medicine and of cell biology and director of the Ruth L and David S Gottesman Institute for Stem Cell and Regenerative Medicine Research at Einstein.

In earlier research, Frenette and colleagues had discovered that the sympathetic nervous system regulates hematopoeitic stem cell niches - the sites in the bone marrow where red blood cells are formed.
Nerves are commonly found around tumours, but their role in the growth and progression of cancer has not been clear.
"Since there might be similarities between the hematopoeitic stem cell niche and the stem cell niches found in cancer, we thought that sympathetic nerves might also have a role in tumour development," said Frenette.

"It turns out that in prostate cancer, not only are sympathetic nerves involved, but so too are parasympathetic nerves," he said.

The body's autonomic nervous system is divided into two branches. The sympathetic nervous system, or SNS, modulates the body's "fight or flight response" by, for example, revving up the heart rate and constricting blood vessels.
The parasympathetic nervous system, or PNS, generally acts in opposition to the SNS to keep bodily functions in balance.
The researchers discovered the role of nerves in prostate cancer by first injecting human prostate cancer cells into mice and then systematically disabling various parts of the SNS and PNS and observing how the cells fared.
A control group of mice were administered the cancer cells but underwent no further interventions.

The study found that SNS helps initiate the early phases of the disease, while the PNS is involved in the later stages when the cancer spreads.
They found that the SNS promotes tumour growth by producing the neurotransmitter norepinephrine, which then binds to and stimulates two types of adrenergic receptors (beta-2 and beta-3) on the surface of the stromal cells in the tumour.
PNS plays a role in cancer progression, it makes tumour cells invade other tissues and travel to distant parts of the body (tumour metastasis) when its nerve fibres release acetylcholine, which activates a signalling pathway in stromal cells of the tumour microenvironment.

The study was published in the journal Science.