Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Cell's Recycling Center Implicated in Division Decisions

29.07.2014

Allows cancer cells to divide even when oxygen-starved

Most cells do not divide unless there is enough oxygen present to support their offspring, but certain cancer cells and other cell types circumvent this rule.

Researchers at The Johns Hopkins University have now identified a mechanism that overrides the cells’ warning signals, enabling cancers to continue to divide even without a robust blood supply.

In the process, the researchers found that lysosomes — the cell’s protein “recycling centers” — help govern cell division decisions. They also uncovered new evidence that certain drugs can halt the growth of tumors that have high levels of the protein HIF-1alpha.

A summary of their findings will be published the week of July 28 in the journal PNAS.

Low levels of oxygen stimulate the production and activation of HIF-1alpha, which protects cells in two ways. Primarily, it turns on several genes for proteins that help the cells adapt to the lack of oxygen. It can also stop the duplication of DNA, which prevents cells from dividing and adding more oxygen-using cells to an already harsh environment.

Knowing that some cells ignore the warnings of HIF-1alpha and divide anyway, Gregg Semenza, M.D., Ph.D., and his team looked for interactions between HIF-1alpha and Cdk1 and Cdk2, proteins known to regulate cell division decisions. They found that HIF-1alpha interacts with both of them, but that Cdk1 increases HIF-1alpha levels, while Cdk2 lowers them.

Semenza’s team suspected that Cdk1 and Cdk2 were acting on HIF-1alpha by marking or not marking it for destruction by the cell’s miniature “garbage disposals,” called proteasomes. But when the researchers blocked proteasome function, they found no changes in HIF-1alpha levels.

Instead, Cdk1 and Cdk2 turned out to alter HIF-1alpha levels by marking or not marking it for destruction by the cell’s lysosomes. To their knowledge, this is the first time lysosomes have been implicated in a cell’s division decisions.

Remarkably, in certain cancer cells, Cdk2 was able to decrease levels of HIF-1alpha while also stimulating its gene activation activity. The net effect was that cells continued dividing while coping with low oxygen levels. In cultured cells, drugs that inhibit Cdk1 prevented HIF-1alpha levels from falling and restored its ability to halt cell division, suggesting they may be effective treatments for certain cancers.

Gregg Semenza is the C. Michael Armstrong Professor of Medicine and a professor of pediatrics, oncology, radiation oncology and biological chemistry at the Johns Hopkins University School of Medicine. Other authors of the report include Maimon Hubbi, Daniele Gilkes, Hongxia Hu and Ishrat Ahmed of the Johns Hopkins University School of Medicine; and Kshitiz of Yale University.

This work was supported by grants from the National Cancer Institute (K99CA181352) and the American Cancer Society.

Catherine Kolf | newswise
Further information:
http://www.jhmi.edu

Further reports about: Cancer Cdk1 Division Medicine Recycling Semenza activation destruction divide drugs levels lysosomes proteins

More articles from Life Sciences:

nachricht New risk factors for anxiety disorders
24.02.2017 | Julius-Maximilians-Universität Würzburg

nachricht Stingless bees have their nests protected by soldiers
24.02.2017 | Johannes Gutenberg-Universität Mainz

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Stingless bees have their nests protected by soldiers

24.02.2017 | Life Sciences

New risk factors for anxiety disorders

24.02.2017 | Life Sciences

MWC 2017: 5G Capital Berlin

24.02.2017 | Trade Fair News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>