Author: Falishia Sloan
Institution: Eastern Virginia Medical School
Date: June 2007
Researchers at the University of Pittsburgh School of Medicine have discovered a thorough way to target and beat cancer in patients by not only attacking the majority of the tumor and the rapidly proliferating cells, but also by eliminating the small group of tumor-initiating, drug resistant cells that survive current cancer treatments, known as "cancer stem cells." This research provides clues to why cancer patients, after being treated with current therapies, still experience relapses.
The research, presented at the Tissue Engineering and Regenerative Medicine International Society (TERMIS) North American Chapter meeting held June 13 to 16 in Toronto, was ground-breaking in that it provided a new target for completely eradicating cancer in patients. Vera Donnenberg, Ph.D., assistant professor of surgery and pharmaceutical sciences, University of Pittsburgh Schools of Medicine and Pharmacy, explained that the existence of a small subset of drug resistant, tumor-initiating cells makes sense, due to the fact that cancers are capable of relapsing after the initial treatment. During a relapse, these cancer stem cells act as a source to regenerate the disease and eventually lead to metastasis.
"Because of the similarities between the way that normal stem cells and cancer stem cells protect themselves," she said, "cancer therapies have to be designed specifically to target cancer stem cells while sparing normal stem cells."
The research team, led by Donnenberg, identified cancer stem cells, regular adult stem cells, and their respective progeny in normal lung and cancerous lung tissue samples using cell surface markers and dyes. During this process, the scientists discovered the rare reservoir of resting cancer stem cells in the samples of the cancerous stem cells, which resembled, acted, and were protected like the adult stem cells present in the normal lung tissue. This protection came in the form of multiple drug resistance transporters that protected the stem cells, even as chemotherapy induced a response from the rest of the tumor.
Written by Falishia Sloan