Navigation Links
Cell's recycling center implicated in division decisions
Date:7/28/2014

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.


'/>"/>

Contact: Catherine Kolf
ckolf@jhmi.edu
443-440-1929
Johns Hopkins Medicine
Source:Eurekalert

Related medicine news :

1. New drug prevents spread of human prostate cancer cells
2. Tiny hitchhikers attack cancer cells
3. To prevent leukemias dreaded return, go for the stem cells
4. Scientists identify major source of cells defense against oxidative stress
5. Therapy exploits addiction of leukemia cells
6. IBN discovers human neural stem cells with tumor targeting ability
7. Leukaemia cells have a remembrance of things past
8. Small molecular bodyguards kill HPV-infected cancer cells by protecting tumor-suppressor
9. Research yields new clues to how brain cancer cells migrate and invade
10. Presence of fetal cells in women lowers risk of breast cancer but raises risk of colon cancer
11. Researchers Rejuvenate Blood-Forming Stem Cells in Mice
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:2/8/2016)... ... 08, 2016 , ... A man who has struggled to quit smoking, a man who has ... determined to find solutions to his problems – and he did. Now Nabat, a serial ... to introduce his breakthrough inventions to the world and better people's lives. His own experience ...
(Date:2/8/2016)... ... 2016 , ... Steve Helwig & Associates Insurance & Financial, serving the families ... teamed up with Citizens Opposed to Domestic Abuse in support of its efforts to ... those victimized by the fear of violence in their own homes, donations may now ...
(Date:2/8/2016)... ... February 08, 2016 , ... ... executive networking and relationship-marketing firm, announced today that nominations will be accepted ... Executive® (ISE®) West Awards. , Awards include the Information Security Executive® ...
(Date:2/8/2016)... ... February 08, 2016 , ... Discover the Rocky Mountain region’s longest running and ... companies. Attendees also get to see the most incredible gardens and home improvement ... , at the Colorado Convention Center - 700 14th St. Denver CO, is an ...
(Date:2/8/2016)... ... February 08, 2016 , ... ... be speaking on how healthcare companies can use newly released government data on ... of a population and intervene and capture the value they create to succeed ...
Breaking Medicine News(10 mins):
(Date:2/8/2016)... , Feb. 8, 2016  Echo Therapeutics, ... device company focused on non-invasive continuous glucose ... today announced that it will host a ... 17, 2015 at 9:00 a.m. Eastern Time ... its corporate strategy, advancements in its CGM ...
(Date:2/8/2016)... --  GS1 US will hold a series of ... Standards implementation to address the requirements of the U.S. ... rule. Scott Brown , director of ... director industry development, medical devices, GS1 US; and ... --> Scott Brown , director of ...
(Date:2/8/2016)... Kan. , Feb. 8, 2016 /PRNewswire/ ... organization that formerly specialized in the development ... recently announced that it has divided its ... Capital. While Nueterra Capital will continue the ... services, NueHealth will operate a national system ...
Breaking Medicine Technology: