Cancer Researchers in Pittsburgh Identify Method of Blocking Cancer Stem Cell Differentiation, Could Lead to More Effective Treatment

May 27, 2010

Scientists from Children’s Hospital of Pittsburgh of UPMC and the University of Pittsburgh School of Medicine have discovered an unprecedented method of permanently blocking cancer stem cells so they remain stem cells instead of differentiating into other types of tumor-forming cells.

The discovery, published in the June issue of the journal Stem Cells, is significant because it will allow researchers to further study and characterize cancer stem cells, as well as screen drugs that could specifically target them.

The research, which involved four different lines of breast cancer stem cells, was led by Edward Prochownik, M.D., Ph.D., director of Oncology Research at Children’s Hospital and the Paul C. Gaffney Professor of Pediatrics and of Molecular Genetics and Biochemistry at the University of Pittsburgh School of Medicine.

Cancer stem cells are heartier than other types of tumor cells because they are generally more resistant to standard chemotherapy and to conditions found inside tumors, such as low oxygen and acidity levels. Although they make up a relatively small portion of a tumor, cancer stem cells are believed to initiate and sustain tumors as they grow and metastasize.

Cancer stem cells differentiate into other cells within three to five weeks of being isolated, making them difficult to study, according to Dr. Prochownik. He and his colleagues at the John G. Rangos Sr. Research Center at Children’s Hospital were able to tag the breast cancer stem cells they isolated with green fluorescent protein and a stem cell-specific promoter know as Oct3/4.

“Using this approach, we can essentially freeze the stem cells in their current state, grow them in unlimited quantities and then study them at our leisure so we’ll be able to understand what makes cancer stem cells more efficient than other types of cancer cells,” Dr. Prochownik said. “More importantly, having this unlimited supply of cancer stem cells allows us to use existing technology to screen them for chemotherapy agents and other therapies to determine which therapies are most effective at destroying the cancer stem cells. The goal is an arsenal of therapies to target both the tumor as a whole as well as those specific to the cancer stem cells.”

The discovery of how to block these cancer stem cells was serendipitous; Dr. Prochownik and his team were initially trying to develop a way to track the cancer stem cells to determine what other types of cells they differentiated into and how long the process takes. Dr. Prochownik’s team at the Rangos Research Center is now studying whether their method of blocking breast cancer stem cells also blocks those from other types of tumors. They also are screening large numbers of drugs to identify new ones that may be more effective against breast cancer stem cells.

Other study authors include: Gangadharan B. Sajithlal, Ph.D., and Kristi Rothermund, Ph.D., Children’s Hospital; Fang Zhang, Ph.D., University of Pittsburgh School of Medicine; David J. Dabbs, Ph.D., Magee-Womens Hospital of UPMC; and Jean J. Lattimer, Ph.D., and Stephen G. Grant, Ph.D., University of Pittsburgh Cancer Institute and University of Pittsburgh School of Medicine.

About Children’s Hospital of Pittsburgh of UPMC

Renowned for its outstanding clinical services, research programs and medical education, Children’s Hospital of Pittsburgh of UPMC has helped establish the standards of excellence in pediatric care. From Ambulatory Care to Transplantation and Cardiac Care, talented and committed pediatric experts care for infants, children and adolescents who make more than 500,000 visits to Children’s and its many neighborhood locations each year.

Children’s also has been named consistently to several elite lists of pediatric health care facilities, including ranking 10th among children’s hospitals (FY 2008) in funding provided by the National Institutes of Health, and is named one of the best pediatric hospitals in the nation by U.S. News & World Report. For more information about Children’s Hospital, visit

About the University of Pittsburgh School of Medicine

As one of the nation’s leading academic centers for biomedical research, the University of Pittsburgh School of Medicine integrates advanced technology with basic science across a broad range of disciplines in a continuous quest to harness the power of new knowledge and improve the human condition. Driven mainly by the School of Medicine and its affiliates, Pitt has ranked among the top 10 recipients of funding from the National Institutes of Health since 1997 and now ranks fifth in the nation, according to preliminary data for fiscal year 2008. Likewise, the School of Medicine is equally committed to advancing the quality and strength of its medical and graduate education programs, for which it is recognized as an innovative leader, and to training highly skilled, compassionate clinicians and creative scientists well-equipped to engage in world-class research. The School of Medicine is the academic partner of UPMC, which has collaborated with the University to raise the standard of medical excellence in Pittsburgh and to position health care as a driving force behind the region’s economy. For more information about the School of Medicine, see