Study Hall presents the results of scientific studies as described by the researchers and their institutions. This week’s report is from Tulane University.

Stem cells of obese women feed tumors

Obesity causes changes in stem cells that can result in cancers growing more aggressively, say scientists at Tulane University School of Medicine in a new study.

“Clinical studies have shown there is a much higher incidence of breast cancer in obese women than in non-obese women,” says Bruce Bunnell, professor of pharmacology and director of Tulane’s Center for Stem Cell Research and Regenerative Medicine, and lead author of the study.

“Our lab has been investigating mesenchymal stem cells from adipose, or fat, tissue,” Bunnell says.

The Tulane team looked at the behavior of stem cells isolated in their lab from fat-tissue samples taken from plastic surgery patients. Specimens of fat were taken from both lean and obese patients, and they were taken from abdominal subcutaneous fat deposits as well as from fat tissues in other parts of the body.

“A tumor is made of cancer cells, and around it is a ‘stromal’ layer of adipose-derived stem cells, which feed the tumor and keep the cancer cells alive,” says Bunnell.

The researchers found that stem cells from fat tissue in morbidly obese patients were much more invasive than those from lean patients, and they contribute more actively to the growth of tumors. When a tumor starts to form, these adipose-derived stem cells “home” aggressively to the tumor in response to the inflammation associated with tumor development, set up a stromal layer and feed the tumor.

“The study points to potential novel avenues for treating breast cancers, not so much focused on killing the tumor cells themselves, but on killing off or regulating the biology of cells that facilitate the cancer cells,” Bunnell says.