Navigation Links
Upending a cancer dogma

Researchers at the University of California, San Diego School of Medicine say a protein essential to regulating cell cycle progression the process of cell division and replication activates a key tumor suppressor, rather than inactivating it as previously thought.

"The finding is the result of literally 20 years of work in my lab," said Steven F. Dowdy, PhD, professor in the Department of Cellular and Molecular Medicine at UC San Diego. "It completely turns upside-down what was thought to be a fundamental aspect of cell cycle progression in all cancer cells driven by one of the most common genetic pathways mutated in cancer, namely the p16-cyclin D pathway."

The findings are published in the journal eLife.

Cyclin D is synthesized during the first stage of cell replication and is believed to help drive the complex, multi-stage process, including interaction with the retinoblastoma (Rb) protein, whose function is to prevent excessive cell growth by inhibiting cell cycle progression until a cell is ready to divide. Rb acts as a tumor suppressor.

But mutated or dysfunctional Rb is associated with several major cancers and Cyclin D has long been described as an oncogene that promotes cancer because it was believed to inactivate the Rb tumor suppressor function through a process called phosphorylation, which involves phosphate molecules being added to proteins, essentially turning them on or off.

Dowdy and colleagues painstakingly counted the number of phosphates added to Rb during cell cycle progression. There are as many as 14, but the scientists found that cyclin D adds just a single phosphate at one, and only one, of the 14 locations during the early G1 phase of cell cycle progression, essentially make 14 different versions of the Rb tumor suppressor. The single phosphate serves to activate Rb, not inactivate it as had been thought for over 20 years.

The researchers said the findings fundamentally change the understanding of G1 cell cycle regulation and the molecular origins of many associated cancers. It is critically important to understand how a genetic pathway actually functions and the consequences of interrupting it, especially in this case where there are multiple drug inhibitors of cyclin D being tested in clinical trials for breast cancer.

Moreover, how the next cyclin, cyclin E, that actually does inactivate Rb becomes activated has not been heavily investigated because it was thought to be the less important second domino, whereas we now know it is the first domino, added Dowdy.


Contact: Jackie Carr
University of California - San Diego

Related medicine news :

1. Cancer Research UKs new funding scheme to nurture future world-leading scientists
2. Biomarker predicts effectiveness of brain cancer treatment
3. GW researcher receives more than $1 million in grants to study epigenetics of pancreatic cancer
4. For cancer patients, sugar-coated cells are deadly
5. Mayo Clinic: Proton therapy has advantages over IMRT for advanced head and neck cancers
6. Mayo Clinic researchers reveal treasure trove of genes key to kidney cancer
7. Enlightening cancer cells
8. Cancer risk: Aspirin and smoking affect aging of genes
9. EORTC presents European solution for effective cancer drug development
10. New approach identifies cancer mutations as targets of effective melanoma immunotherapy
11. Case Western Reserve, University Hospitals fundraising for adolescent, young adult cancer
Post Your Comments:
Related Image:
Upending a cancer dogma
(Date:6/25/2016)... ... June 25, 2016 , ... Dr. Calvin Johnson has dedicated ... has implemented orthobiologic procedures as a method for treating his patients. The procedure ... doctors to perform the treatment. Orthobiologics are substances that orthopaedic surgeons use to ...
(Date:6/24/2016)... ... ... Those who have experienced traumatic events may suffer from a complex set ... drug or alcohol abuse, as a coping mechanism. To avoid this pain and suffering, ... traumatic event. , Trauma sufferers tend to feel a range of emotions, from depression, ...
(Date:6/24/2016)... MIAMI, Fla. (PRWEB) , ... June 24, 2016 , ... ... Florida Trend magazine’s 2016 Legal Elite. The attorneys chosen by their peers for this ... of Florida. , Seven Greenberg Traurig Shareholders received special honors as members of this ...
(Date:6/24/2016)... (PRWEB) , ... June 24, 2016 , ... People across ... in Genome magazine’s Code Talker Award, an essay contest in which patients and their ... award to be presented at the 2016 National Society of Genetic Counselors (NSGC) Annual ...
(Date:6/24/2016)... , ... June 24, 2016 , ... ... actively feeding the Frederick area economy by obtaining investment capital for emerging technology ... past 2½ years that have already resulted in more than a million dollars ...
Breaking Medicine News(10 mins):
(Date:6/24/2016)... and SAN CLEMENTE, Calif. , June ... -based mobile pulmonary function testing company, is now able to ... devices developed by ndd Medical Technologies , Inc. ... done in hospital-based labs.  Thanks to ndd,s EasyOne PRO ® , ... , can get any needed testing done in the comfort of ...
(Date:6/24/2016)... 2016  Arkis BioSciences, a leading innovator in ... durable cerebrospinal fluid treatments, today announced it has ... is led by Innova Memphis, followed by Angel ... investors.  Arkis, new financing will accelerate the commercialization ... release of its in-licensed Endexo® technology. ...
(Date:6/23/2016)... 23, 2016  In a startling report released today, National ... by lacking a comprehensive, proven plan to eliminate prescription opioid overdoses. ... of how states are tackling the worst drug crisis in recorded ... – Kentucky , New Mexico ... . Of the 28 failing states, three – Michigan ...
Breaking Medicine Technology: