This study confirms at least one of those concepts, the researchers said. "Our study demonstrates that the very small subset of cells in a human pancreatic tumor that cause the cancer to grow and propagate have stem cell-like features," Simeone said.
To look for cancer stem cells in pancreatic cancer, the research team implanted cancerous tissue from human pancreatic specimens removed during patient surgery in "xenograft" mice with compromised immune systems. Researchers removed tumors after they grew, and then sorted millions of cancer cells to isolate those that had one or more of three surface protein markers -- CD44, CD24, and ESA. They chose these markers, called cell adhesion molecules, because they'd recently been found on isolated breast cancer cells by study co-authors Max Wicha, M.D., from Michigan and Michael Clarke, Ph.D., from Stanford University School of Medicine.
The researchers then implanted about 100 of each type of cell in mice, and found that tumors would grow in a subset of the animals, but cells that expressed all three markers were the most potent, producing tumors in six of 12 mice tested. If more cells are used, "we can get tumors to grow 100 percent of the time," Simeone said. "These cells are highly tumorigenic, which reflects the biology of this cancer."
Additionally, the tumors derived from the highly tumorigenic pancreatic cancer cells "appeared remarkably similar to the appearance of tumors taken directly from patients," Simeone said. The purported cancer stem cells produced a diverse mixture of cells, some of which are n
Contact: Greg Lester
American Association for Cancer Research