Opening up a new pathway to fight cancer, researchers at the University of Pennsylvania have found a way to target an enzyme that is crucial to tumor growth while also blocking the mechanism that has made past attempts to target that enzyme resistant to treatment. Researchers were able to use this finding to develop a drug that successfully inhibits tumor growth of melanoma as well as pancreatic and colorectal cancer in mice. The journal Cancer Discovery published the findings online this month.
Opening up a new pathway to fight cancer, researchers at the University of Pennsylvania have found a way to target an enzyme that is crucial to tumor growth while also blocking the mechanism that has made past attempts to target that enzyme resistant to treatment. Researchers were able to use this finding to develop a drug that successfully inhibits tumor growth of melanoma as well as pancreatic and colorectal cancer in mice. The journal Cancer Discovery published the findings online this month.
The target is an enzyme called PPT1, which controls both the mechanistic target of rapamycin (mTOR), a major regulator of growth in cancer cells, as well as a process called autophagy, a built-in resistance mechanism which allows cells to survive when under attack by breaking down unneeded parts and recycling them to stay alive. Numerous drugs that target mTOR are approved by for cancer patients by the U.S. Food and Drug Administration, but targeting mTOR with these currently available inhibitors turns on autophagy, thus making the tumor resistant.
“What we learned in this study is that mTOR and autophagy aren’t opposed to each other as previously thought. They’re actually complementary, because autophagy provides the nutrients that allow mTOR to direct growth, while mTOR shuts off autophagy when the nutrients aren’t needed,” said co-senior author Ravi K. Amaravadi, MD, an associate professor of Hematology Oncology in the Perelman School of Medicine at the University of Pennsylvania and a member of Penn’s Abramson Cancer Center.
That yin and yang relationship takes place in a part of the cell called the lysosome. Previously, it has taken two drugs to stop both processes, but by focusing on drugs that hone in on the lysosome more efficiently, researchers have found one drug that can block both.
Read more at University of Pennsylvania School of Medicine
Image: A model of Penn's new approach using DQ611 to target PPT1, which inhibits both mTOR and autophagy. (Credit: Penn Medicine)
