PTEN, PKR and prostate cancer

Researchers at the Jewish General Hospital (affiliated with McGill University) in Montreal (Québec) have uncovered a new link between two genetic pathways that curtail the growth of tumours. The discovery, made along with American colleagues, may lead to new treatments for several types of cancer, including prostate cancer.

The scientists made the association between the phosphatase and tensin homolog (PTEN) gene, which suppresses tumours, and the PKR protein, known to inhibit protein synthesis.

When PTEN is lacking or undergoes a mutation (change), PKR loses its restraining ability, thus allowing for unchecked growth of the affected cells. The greater survival capacity of these cells compared to normal cells facilitates tumour development. By understanding more about how PTEN mutations function, researchers may come up with new drugs specifically designed to set in motion PKR’s protein synthesis “inhibition switch.”

The study also showed that DNA damage — which some chemotherapy regimens are known to cause — can itself trigger the PKR pathway. So, in addition to drugs that are specific to PKR, another possible lead the research points to is the use of therapies that have a more general effect on DNA and that activate the PKR pathway “coincidentally.”