Washington, Nov 28: Scientists at Thomas Jefferson University, Philadelphia, have found that a gene that regulates the ageing process also helps prevent the growth of prostate cancer cells.
The scientists, led by Kimmel Cancer Centre director Dr. Richard Pestell, hope that their findings will help understand how exactly prostate cancer develops, and lead to new drugs against the disease.
They say that SIRT1, a member of a family of enzymes called sirtuins, have far-reaching influence in all organisms, including roles in metabolism, gene expression and ageing.
"We know that sirtuins play a role in ageing, and that the risk for prostate cancer increases with ageing, but no one has ever linked the two until now," says Dr. Pestell, who is also professor and chair of cancer biology at Jefferson Medical College.
"We've shown that by making a prostate cancer with cells overexpressing a mutation for the androgen receptor, which is resistant to current forms of therapy, we can almost completely block the growth of these cells with SIRT1," he added.
In one experiment, Dr. Pestell and his colleagues took a series of mutations in androgen receptors from prostate cancer patients who are resistant to hormonal therapy, and found that the SIRT1 gene blocks receptor activity, thereby halting cancer growth.
"We systematically tested each androgen receptor mutation," Dr. Pestell explains.
"These mutant receptors are resistant to current therapies and are all blocked by expression of SIRT1," he says, adding that prostate specific antigen (PSA) levels were used to confirm this.
The researchers also found a single amino acid within the androgen receptor that reacts with SIRT1’s enzymatic activity. Lab experiments showed that it was key to SIRT1’s cancer-halting effect.
Dr. Pestell says that their work can lead to a model for drug screening.
"This study shows that there is potentially new opportunity for these cancer patients with drugs that regulate SIRT1," Dr. Pestell says.
The study has been published in the journal Molecular and Cellular Biology. (ANI)