Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Inhibiting key enzymes kills difficult tumor cells in mice

16.08.2011
Tumors that do not respond to chemotherapy are the target of a cancer therapy that prevents the function of two enzymes in mouse tumor cells, according to Pennsylvania medical researchers.

"We've known for well over a decade that when tumors become hypoxic they become resistant to chemotherapy and radiotherapy," said Wafik S. El-Deiry, M.D. Ph.D., American Cancer Society Research Professor, Rose Dunlap Professor and chief of hematology/oncology, Penn State College of Medicine. "This is a huge problem in the treatment of patients with cancer. As tumors progress, they have regions that are not well perfused with blood vessels and tumors become hypoxic."

A hypoxic tumor lacks oxygen because there are not enough blood vessels within the tumor to allow red blood cells to transport oxygen throughout the tumor.

El-Deiry and his team report in a recent issue of Cancer Research that the drug sangivamycin-like molecule 3 (SLM3) helps keep tumor cells from multiplying in lab mice.

Treating a tumor with SLM3 inhibits two kinase, or enzymes: GSK-3ß, which regulates cell growth and cell death, and CDK1, which regulates cell division and blood vessel growth. Tumor cells treated with SLM3 become more sensitive to chemotherapy and die, according to El-Deiry and his colleagues.

"If you just inhibit GSK-3ß, that may not be enough and not necessarily desirable," said El-Deiry, who is also the associate director for translational research, Cancer Institute. "But there's something fortuitous about the dual targeting of these two kinases, (GSK-3ß and CDK-1), with respect to cancer therapy. If you inhibit these two kinases, the dual inhibition works together to kill hypoxic tumor cells.

"While pure inhibition of GSK-3ß can promote cell proliferation, the combination of GSK-3ß and CDK-1 inhibition not only inhibits cell proliferation but also promotes cell death," El-Deiry added.

To find SLM3, the researchers screened a chemical library looking for molecules that induce apoptosis -- cell death -- in hypoxic tumor cells. SLM3 does that, and the researchers found eight molecules whose structures were similar.

SLM3 was the version that induced the most cell death in concert with TRAIL, a naturally occurring molecule in the body that tells a cell it is time to die. TRAIL sets a process in motion that targets and shuts down tumor cells and keeps them from spreading.

SLM3, a nucleoside analog, helps keep tumor cells from multiplying by stopping cells before they duplicate their DNA. Nucleosides are the building blocks of nucleic acids and molecules like ATP -- the energy source for the body. A nucleoside analog competes with ATP and inhibits kinases, like GSK-3ß and CDK1.

GSK-3ß helps regulate cell growth and cell death. CDK1 decreases the tumor's ability to divide and generate more blood vessels. SLM3 inhibits both these kinases.

"The bottom line is the molecules actually work to shrink tumors when these molecules are combined with chemo or TRAIL therapy," El-Deiry said. "We think that these are important observations that need to be tested further in the clinic."

Other Penn State College of Medicine researchers include Nathan G. Dolloff, assistant professor of hematology/oncology; Joshua E. Allen, graduate student, hematology/oncology; Yingqiu Y. Liu, research specialist; and David T. Dicker, technical specialist.

Also working on this research were Patrick A. Mayes, former graduate student, now at GlaxoSmithKline; Colin J. Daniel, graduate student, and Rosalie C. Sears, associate professor, molecular and medical genetics, Oregon Health Science University; J. Judy Liu and David I. H. Jee, graduate students, Harvard University; Lori S. Hart, research associate, and Jay F. Dorsey, assistant professor, radiation oncology, Emma E. Furth, professor of pathology and laboratory medicine and Peter S. Klein, associate professor of hematology/oncology, University of Pennsylvania; Kageaki Kuribayashi, Sapporo Medical University, Japan; and J. Martin Brown, professor of radiation oncology, Stanford University.

The National Institutes of Health supported this research.

Victoria M. Indivero | EurekAlert!
Further information:
http://www.psu.edu

More articles from Life Sciences:

nachricht How brains surrender to sleep
23.06.2017 | IMP - Forschungsinstitut für Molekulare Pathologie GmbH

nachricht A new technique isolates neuronal activity during memory consolidation
22.06.2017 | Spanish National Research Council (CSIC)

All articles from Life Sciences >>>

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

Individualized fiber components for the world market

23.06.2017 | Physics and Astronomy

How brains surrender to sleep

23.06.2017 | Life Sciences

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

23.06.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>