Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Scientists uncover indicator that warns leukemia is progressing to more dangerous form

18.02.2009
Scientists at the Moores Cancer Center at the University of California, San Diego, Stanford University School of Medicine and other centers have identified a mechanism by which a chronic form of leukemia can progress into a deadlier stage of the disease.

The findings may provide physicians with an indicator of when this type of cancer – chronic myeloid leukemia (CML) – is progressing, enabling them to make more accurate prognoses for the disease and improved treatment choices.

"If we can predict when a patient is moving from the chronic phase in CML to the blast crisis stage, then we can hopefully intervene before it's too late," said Catriona H.M. Jamieson, MD, PhD, assistant professor of medicine at the UC San Diego School of Medicine and Director for Stem Cell Research at the Moores UCSD Cancer Center.

The findings, reported online during the week of February 16, 2009 in the Proceedings of the National Academy of Sciences, also shed light on the development of potentially treatment-resistant leukemia stem cells and provide insights for new strategies against CML and other cancers.

Led by Jamieson and Irving Weissman, MD, director of the Stem Cell Biology and Regenerative Medicine Institute at the Stanford University School of Medicine, the researchers discovered that when a molecular off-switch called glycogen synthase kinase (GSK) 3 beta becomes faulty in chronic stage CML cells, it fails to turn off another protein, beta-catenin. This in turn enables pre-leukemia stem cells to develop into leukemia stem cells and expand their numbers, leading to progression to the more dangerous "blast crisis" stage of CML. This errant off-switch is a potential therapeutic target, Jamieson explained.

"This paper further underscores the importance of the cell type and specific context of molecular events in the evolution of leukemia," Jamieson said. "It also highlights the malignant consequences of GSK 3 beta deregulation."

"This knowledge may enable us to design and develop more effective, personalized therapies for these patients," said staff research associate and co-first author Annelie Abrahamsson.

In CML, an enzyme called ABL goes in overdrive because of a chromosomal mix-up that occurs during blood cell development. The genes ABL and BCR fuse and produce a hybrid BCR-ABL enzyme that drives the excessive proliferation of white blood cells. CML progresses from a chronic stage in hematopoietic stem cells that carry BCR-ABL to the blast crisis stage. This stage is characterized by the over-production of beta-catenin in white blood cells called granulocyte macrophage progenitors (GMP) – in effect, leukemia stem cells.

According to Jamieson, a major roadblock in predicting and stopping the conversion of chronic CML to blast crisis stage was the failure to understand what turned on beta-catenin. The team showed that by injecting blast crisis CML progenitor cells – GMP – into mice lacking working immune systems, they could "transplant" leukemia into the animals. When they did this, they discovered that GSK 3 beta levels dropped. Looking more closely, they found an aberrant "misspliced" form of GSK 3 beta that was unable to turn off beta-catenin, suggesting a potential mechanism behind the change to blast crisis stage.

The scientists also showed that the mice that had received the cells with the bad form of GSK 3 beta developed granulocytic sarcomas, tumors that are seen in patients with the most advanced form of CML.

"Many investigators have questioned the usefulness of finding and purifying leukemia and cancer stem cells," said Weissman. "This paper shows why. The damage to the enzyme GSK 3 beta that prevents beta-catenin activation of cell proliferation occurs only in the GMP leukemia stem cells, which are only about 1 in 20 bone marrow cells. Trying to analyze the missplicing of GSK in the whole leukemia would not have worked.

"These kinds of changes in gene expression, which are not mutations, need pure cells to find them. The final proof of the cancer stem cell hypothesis will be to show whether a treatment specific for the changed gene expression eliminates the cancer in the patient."

"Downregulating beta-catenin and GSK deregulation may have other implications in many cancers," Jamieson said. "By studying CML, we can understand the molecular evolution of disease and the stepwise progression to cancer. It becomes a useful paradigm for understanding how cancers evolve and the pathways that are essential to escape the normal control mechanisms."

Steve Benowitz | EurekAlert!
Further information:
http://www.ucsd.edu

More articles from Health and Medicine:

nachricht Cystic fibrosis alters the structure of mucus in airways
28.06.2017 | University of Iowa Health Care

nachricht Mice provide insight into genetics of autism spectrum disorders
28.06.2017 | University of California - Davis

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Supersensitive through quantum entanglement

28.06.2017 | Physics and Astronomy

X-ray photoelectron spectroscopy under real ambient pressure conditions

28.06.2017 | Physics and Astronomy

Mice provide insight into genetics of autism spectrum disorders

28.06.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>