Controversial cancer stem cells offer new direction for treatment

June 25, 2009

In a review in Science, a University of Rochester Medical Center researcher sorts out the controversy and promise around a dangerous subtype of cancer cells, known as cancer stem cells, which seem capable of resisting many modern treatments.

The article proposes that this subpopulation of malignant cells may one day provide an important avenue for controlling cancer, especially if new treatments that target the cancer stem cell are developed and combined with traditional chemotherapy and/or radiation.

"The fact that these concepts are steadily making their way into the clinic is exciting, and suggests that the recent interest in cancer stem cells may yield beneficial outcomes in potentially unexpected ways," wrote co-authors Craig T. Jordan, Ph.D., professor of Medicine at URMC and director of the James P. Wilmot Cancer Center Translational Research for Hematologic Malignancies program; and Jeffrey Rosen, Ph.D., the C.C. Bell Professor of Molecular and Cellular Biology and Medicine at Baylor College of Medicine.

Cancer stem cells (CSCs) are a hot topic in the scientific community. First identified in 1994 in relation to acute myeloid leukemia, CSCs have now been identified in several solid tumors in mice as well. Scientists who study CSCs believe they have distinct properties from other cancer cells, and may be the first cells to undergo mutations.

Research from the past 10 years suggests that because CSCs may be the root of cancer, they also might provide a new opportunity for a treatment. Jordan and a group of collaborators, for example, are testing a new drug compound based on the feverfew plant that demonstrates great potential in the laboratory for causing leukemia CSCs to self destruct.

Another new approach, the authors said, is the use of chemical screens to search drug libraries for already approved agents that may target CSCs, or make resistant tumor cells more sensitive to chemotherapy and radiation.

Cancer stem cell biologists hypothesize that any treatment that targets the source of origin rather than simply killing all cells, healthy and malignant, would be an improvement over most conventional therapies.

Some scientists, however, are uncertain if CSCs have unique biological properties or any relevance to treatment, the authors noted. What is more likely to fuel cancer, other studies have found, are unfavorable factors in the neighboring cells surrounding the tumor, such as mutated genes, proteins that encourage cell growth, and a poor immune system, for instance.

The most challenging issue facing CSC biologists is that the number and type of cancer stem cells can vary from patient to patient. In some tumor samples, for example, CSCs are rare while in others they constitute a large portion of the tumor mass, the authors said.

To understand why CSCs are so variable, investigators are trying to determine what genes and pathways are responsible for activating cancers that have a poor prognosis, and whether these cancers also have a higher frequency of CSCs.

"Whether the cancer stem cell model is relevant to all cancers or not," they wrote, "it is clear that we need new approaches to target tumor cells that are resistant to current therapies and give rise to recurrence and treatment failure."

An unexpected benefit of so much attention on normal stem cells is that it has stimulated research in areas not previously the focus of cancer therapies, Jordan and Rosen said.

For example, pathways known to be important for normal stem cell self-renewal, such as the Wnt, Notch and Hedgehog(Hh) pathways, are now of increased interest due to their potential role in CSCs. The first clinical trial using an agent to block the Notch pathway in combination with chemotherapy for breast cancer has begun.

The authors conclude by spotlighting the pressing need for preclinical models to test appropriate doses and combinations of CSC therapies before they can move into human clinical trials.
-end-


University of Rochester Medical Center

Related Cancer Articles from Brightsurf:

New blood cancer treatment works by selectively interfering with cancer cell signalling
University of Alberta scientists have identified the mechanism of action behind a new type of precision cancer drug for blood cancers that is set for human trials, according to research published in Nature Communications.

UCI researchers uncover cancer cell vulnerabilities; may lead to better cancer therapies
A new University of California, Irvine-led study reveals a protein responsible for genetic changes resulting in a variety of cancers, may also be the key to more effective, targeted cancer therapy.

Breast cancer treatment costs highest among young women with metastic cancer
In a fight for their lives, young women, age 18-44, spend double the amount of older women to survive metastatic breast cancer, according to a large statewide study by the University of North Carolina at Chapel Hill.

Cancer mortality continues steady decline, driven by progress against lung cancer
The cancer death rate declined by 29% from 1991 to 2017, including a 2.2% drop from 2016 to 2017, the largest single-year drop in cancer mortality ever reported.

Stress in cervical cancer patients associated with higher risk of cancer-specific mortality
Psychological stress was associated with a higher risk of cancer-specific mortality in women diagnosed with cervical cancer.

Cancer-sniffing dogs 97% accurate in identifying lung cancer, according to study in JAOA
The next step will be to further fractionate the samples based on chemical and physical properties, presenting them back to the dogs until the specific biomarkers for each cancer are identified.

Moffitt Cancer Center researchers identify one way T cell function may fail in cancer
Moffitt Cancer Center researchers have discovered a mechanism by which one type of immune cell, CD8+ T cells, can become dysfunctional, impeding its ability to seek and kill cancer cells.

More cancer survivors, fewer cancer specialists point to challenge in meeting care needs
An aging population, a growing number of cancer survivors, and a projected shortage of cancer care providers will result in a challenge in delivering the care for cancer survivors in the United States if systemic changes are not made.

New cancer vaccine platform a potential tool for efficacious targeted cancer therapy
Researchers at the University of Helsinki have discovered a solution in the form of a cancer vaccine platform for improving the efficacy of oncolytic viruses used in cancer treatment.

American Cancer Society outlines blueprint for cancer control in the 21st century
The American Cancer Society is outlining its vision for cancer control in the decades ahead in a series of articles that forms the basis of a national cancer control plan.

Read More: Cancer News and Cancer Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.