A new study by researchers at the University of Rochester Medical Center in the United States has found that a key molecule can reprogram immune cells that normally protect the body from infection and cancer, and turn them into harmful cells that promote cancer growth, preventing the immune system from defending the body and making it unable to eliminate the cells.
“Studying the behavior of these (pro-tumor) immune cells is important because they may be targets for treatments that prevent their harmful activity,” said Dr. Minsoo Kim, co-author of the study and chief research officer at the Wilmoth Cancer Institute, according to EurekAlert. The study results 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 environment and the underlying factors that cause immune cells to switch from good to bad.
Platelet activating factor
Platelet-activating factor (PAF) was first known for its ability to stimulate platelet aggregation and dilate blood vessels. Today, it is also known as a potent mediator of inflammation, allergic reactions, and shock. Platelet-activating factor causes severe inflammation of the airways, leading to symptoms similar to those of asthma.
Platelet activating factor production is stimulated by toxins from destroyed bacterial fragments, leading to vasodilation and a drop in blood pressure, which leads to decreased heart pumping and shock. Platelet activating factor is also associated with many conditions such as asthma, stroke, myocardial infarction, some tumors and cancers, and many other inflammatory conditions.
Researchers have discovered that platelet-activating factor is the key molecule that controls the fate of immune cells.
From protecting the body to harming it
Platelet-activating factor not only recruits pro-cancer cells, but also suppresses the immune system’s ability to fight back. In addition, they found that many cancers depend on platelet-activating factor signaling.
“That may be the most important thing, because if we find a treatment that can interfere with platelet-activating factor, it could be applicable to many types of cancer,” said Kim, who is also a professor of microbiology and immunology at the University of Rochester School of Medicine.
Much of the team’s work has focused on pancreatic cancer cells. This cancer is considered one of the deadliest types, with a five-year survival rate of about 12 percent. It is also difficult to treat because pancreatic tumors are surrounded by a toxic mix of proteins and other tissues that protect the cancer from natural attacks, and the immune system plays a role in attacking invaders.