A new study by researchers at the University of Rochester Medical Center in the United States has revealed that a key molecule can reprogram immune cells that normally protect the body from infection and cancer, transforming them into harmful cells that promote cancer growth. This prevents the immune system from defending the body and renders it unable to eliminate the invading cancer cells.
Dr. Minsoo Kim, co-author of the study and research leader at the Wilmot Cancer Institute, told EurekAlert that "studying the behavior of these (pro-tumor) immune cells is important because they may be targets for therapies that inhibit their harmful activity." The study's findings were published in the journal PNAS on August 23.
Kim led a team of scientists to study the dynamic interactions that occur between cells in the tumor microenvironment and the underlying factors that cause the harmful transformation of immune cells from healthy to malignant.
Platelet-activating factor (PAF) was first identified for its ability to stimulate platelet aggregation and vasodilation. It is now also known as a potent mediator of inflammation, allergic responses, and shock. Platelet-activating factor (PAF) causes severe inflammation in the airways, leading to asthma-like symptoms.
PAF production is stimulated by toxins produced from fragments of damaged bacteria, resulting in vasodilation and a drop in blood pressure, which in turn leads to decreased cardiac output and shock. PAF is also linked to numerous medical conditions, including asthma, stroke, myocardial infarction, certain tumors and cancers, and many other inflammatory conditions.
Researchers have found that PAF is a key molecule that controls the fate of immune cells.
From protecting the body to harming it, PAF not only recruits pro-cancer cells but also suppresses the immune system's ability to fight back. Furthermore, they discovered that many cancers rely on PAF signaling.
“This could be the most important thing,” said Kim, who is also a professor of microbiology and immunology at the University of Rochester Medical Center, “because if we find a treatment that can interfere with the action of platelet-activating factor, it could be applicable to many types of cancer.”
Much of the team’s work has focused on pancreatic cancer cells. This cancer is one of the deadliest, with a five-year survival rate of about 12%, and is difficult to treat because pancreatic tumors are surrounded by a toxic mixture of proteins and other tissues that protect the cancer from the immune system’s normal attack on invaders.