In a new study, Indian-origin scientist from University of Kentucky has found that human cells secrete protein that kills cancer cells.
The research team led by Vivek Rangnekar, UK professor of radiation medicine, have determined that the tumour-suppressor protein Par-4, initially thought to be active only within cells expressing the Par-4 gene, is in fact secreted by most human and rodent cells and can target large numbers of cancer cells by binding to receptors on the cell surface.
They claim that Par-4 an attractive molecule for future research aimed at developing new cancer treatments.
"It was a pleasant surprise, when we noticed that Par-4 protein is secreted by cells," Rangnekar said.
"This new finding means it is not necessary to make genetic modifications, or to employ recombinant viruses, to deliver the Par-4 gene to cancer cells, and it significantly expands the potential applications of Par-4 to selectively kill cancer cells," he added.
The study showed that when Par-4 molecule binds to its receptor GRP78 on the surface of a tumour cell, it triggers a biological process called apoptosis or "cell suicide."
The newly discovered secreted Par-4 acts selectively against cancer cells, leaving healthy cells unharmed. Few other molecules are known to exhibit such selectivity.
While Par-4 is not necessarily a "magic bullet" - it does not target every type of cancer cell - Rangnekar says it could play a major role in developing new combination treatment modalities for cancer patients.
He hopes that the next generation of treatments will be even more effective than conventional treatments, with fewer and less severe side effects.
The findings appear in journal Cell.