Cell surface protein blows potent cells cover; targeted drug works in preclinical tests

Newswise HOUSTON Breast cancer stem cells wear a cell surface protein that is part nametag and part bulls eye, identifying them as potent tumor-generating cells and flagging their vulnerability to a drug, researchers at The University of Texas MD Anderson Cancer Center report online in Journal of Clinical Investigation.

Weve discovered a single marker for breast cancer stem cells and also found that its targetable with a small molecule drug that inhibits an enzyme crucial to its synthesis, said co-senior author Michael Andreeff, M.D., Ph.D., professor in MD Andersons Departments of Leukemia and Stem Cell Transplantation and Cellular Therapy.

Andreeff and colleagues are refining the drug as a potential targeted therapy for breast cancer stem cells, which are thought to be crucial to therapy resistance, disease progression and spread to other organs.

Its been difficult to identify cancer stem cells in solid tumors, Andreeff said. And nobody has managed to target these cells very well.

The marker is the cell surface protein ganglioside GD2. The drug is triptolide, an experimental drug that Andreeff has used in preclinical leukemia research. The team found triptolide blocks expression of GD3 synthase, which is essential to GD2production.

Triptolide stymied cancer growth in cell line experiments and resulted in smaller tumors and prolonged survival in mouse experiments. Drug development for human trials probably will take several years.

Cancer stem cells are similar to normal stem cells

Research in several types of cancer has shown cancer stem cells are a small subpopulation of cancer cells that are capable of long-term self-renewal and generation of new tumors. More recent research shows they resist treatment and promote metastasis.

Cancer stem cells are similar to normal stem cells that renew specialized tissues. The breast cancer findings grew out of Andreeffs long-term research in mesenchymal stem cells, which can divide into one copy of themselves and one differentiated copy of a bone, muscle, fat or cartilage cell.

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Scientists Discover Marker to Identify, Attack Breast Cancer Stem Cells