Drs. Andrew Goldstein, Owen Witte and Tanya Stoyanova and colleagues at the University of California, Los Angeles' Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, said scientists must be prepared for the continual evolution of the stem cell as tumors adapt and become resistant to new and more potent therapies.
The study, published online ahead of print in the Proceedings of the National Academy of Sciences, found prostate cancer can develop in one type of stem cell, then evolve to be maintained by a stem cell that looks very different, creating a moving target for treatments.
The breakthrough discovery connects directly to the development of future therapeutics that target cancer, the researchers said.
Adult stem cells are tissue-specific regenerative cells that replace diseased or damaged cells in the body's organs. The researchers had previously reported in the journal Science that prostate cancer can start in basal type stem cells. Building on that discovery, they found that tumors can start in basal stem cells that evolve to luminal-like cells. This means the source of the disease they wish to target with therapy -- the tumor stem cell -- can change over time.
"People have begun to think about cancers as being driven by stem cells in the same way that many of our adult organs are maintained by dedicated stem cells, based on this new understanding, a lot of excitement surrounds the concept of going right to the root of the tumor and targeting those stem cells to eradicate the cancer," Goldstein said in a statement.
In patients with aggressive prostate cancer who are being treated with anti-androgen therapy -- to reduce levels of male hormones -- the basal stem cells that start the cancer look different from the luminal cells that maintain the aggressive disease, and in turn the tumor stem cells that remain after the anti-androgen treatment look different from the previous two, the study said.
This means that for targeting treatments, researchers need to identify cell types that evolve as the disease and its treatment progress, the researchers concluded.