New therapeutic target found for pancreatic cancer

Researchers at New York University's School of Medicine have discovered how pancreatic tumor cells feed themselves to grow and survive, uncovering a new possible therapeutic target to treat the notoriously deadly cancer.

Pancreatic cancer is a leading cause of cancer death, killing nearly 38,000 Americans annually, and most diagnosed with the disease live less than a year.

Scientists have known that a mutated protein called Ras plays a central role in a complex molecular chain of events that drives cancer cell growth and proliferation in many cancers, including pancreatic, lung, and colon cancer. Ras cancer cells have special nutrient requirements to thrive and subsist, but what has remained a mystery is how these cells meet these extraordinary nutritional necessities.

In a new study, researchers at NYU School of Medicine have shown how Ras cancer cells exploit a process called macropinocytosis to "swallow up" the protein albumin, which cells then reap for amino acids essential for growth.

"This work offers up a completely different way to target cancer metabolism," said the study's lead principal investigator, Dafna Bar-Sagi, in a statement. Bar-Sagi, who is senior vice president and vice dean for science, chief scientific officer of NYU Langone Medical Center, first identified macropinocytosis in Ras-transformed cancer cells.

The research suggests that Ras cancer cells depend on this process of macropinocytosis, or "protein eating," for survival. When they used a chemical to block the uptake of albumin via macropinocytosis in mice with pancreatic tumors, researchers saw that tumor growth stopped, and some of the tumors even shrank. They also noticed that the pancreatic cancer cells in mice carried more macropinosomes--the vesicles that transport nutrients into a cell--than did the cells of normal mice.

The scientists believe the discovery of this mechanism that occurs in some cancer cells could be a possible new therapeutic target by blocking this engulfing process, easing the way for chemotherapy drugs to be carried into cancer cells.

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