Navigation Links
New mechanism of action for PARP inhibitors discovered
Date:11/9/2012

PHILADELPHIA New understanding of how drugs called PARP inhibitors, which have already shown promise for the treatment of women with familial breast and ovarian cancers linked to BRCA mutations, exert their anticancer effects has led to the identification of ways in which the patient population that might benefit from PARP inhibitors could be expanded.

Yves Pommier, M.D., Ph.D., chief of the Laboratory of Molecular Pharmacology at the National Cancer Institute's Center for Cancer Research in Bethesda, Md., and colleagues reported these data in Cancer Research, a journal of the American Association for Cancer Research.

"In recent years, drugs classified as poly (ADP-ribose) polymerase (PARP) inhibitors have been shown to be promising anticancer agents for breast and ovarian cancers deficient in either BRCA1 or BRCA2," said Pommier. "Prior to our study, PARP inhibitors were thought to work primarily by blocking the DNA repair function of members of the PARP family of proteins, leading ultimately to cancer cell death."

In their initial studies, Pommier and his colleagues found that the PARP inhibitor olaparib was more toxic to cultured cells than genetic elimination of PARP1.

According to Pommier, these results indicated that olaparib must have additional modes of action, and their detailed cellular analyses identified a critical one: olaparib was trapping PARP proteins, specifically PARP1 and PARP2, at sites of DNA damage, and the trapped PARP protein-DNA complexes were highly toxic to cells.

When the trapping ability of olaparib was compared with that of two other PARP inhibitors under clinical development, it was found that the trapping potency of the three drugs differed markedly: niraparib was more potent than olaparib, which was in turn substantially more potent than veliparib. In contrast, olaparib was the most potent inhibitor of DNA repair function, followed by veliparib and then niraparib.

"Critical to this study, is the demonstration that PARP inhibitors are not equivalent with respect to their potency to trap PARP proteins," said Pommier. "Our findings indicate that PARP inhibitors should be categorized according to their potency to trap PARP, in addition to their ability to inhibit DNA repair. This is important because it might explain differences in the results of clinical trials using distinct PARP inhibitors."

In further experiments, the researchers identified several genetic mutations in post-replication repair and Fanconi anemia pathways that, like BRCA1 and BRCA2 mutations, sensitized cultured cells to the toxic effects of trapped PARP protein-DNA complexes.

"These data suggest that patients with cancers deficient in these PARP inhibitor-sensitizing genes might benefit from treatment with PARP inhibitors," said Pommier. "It is clear, however, that this hypothesis will require rigorous testing before being broadly translated to the clinic."


'/>"/>
Contact: Jeremy Moore
Jeremy.Moore@aacr.org
215-446-7109
American Association for Cancer Research
Source:Eurekalert

Related medicine news :

1. Mechanism found for destruction of key allergy-inducing complexes, Stanford researchers say
2. Researchers reveal underlying mechanism of powerful chemotherapy for prostate cancer treatment
3. Scientist receives $2.8 Million to study cell signaling mechanism and develop potential therapeutics
4. WSU researchers discover mechanism leading from trichomoniasis to prostate cancer
5. Human Airways Brush Mechanism Gives Clues to Lung Diseases
6. Mechanisms of acquired chemoresistance in ovarian cancer identified
7. Moffitt Cancer Center researchers discover how cancer cells hijack a mechanism to grow
8. New regulatory mechanism discovered in cell system for eliminating unneeded proteins
9. Researchers unfold the mechanisms underlying blood disorders
10. Study reveals new mechanism that might promote cancers growth and spread in the body
11. Zebrafish reveal promising mechanism for healing spinal cord injury
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:6/27/2016)... ... , ... TopConsumerReviews.com recently awarded their highest five-star rating to Best Buy Eyeglasses, ... the United States and Canada wear eyeglasses. Once considered to be a purely functional ... a fashion statement. Even celebrities use glasses as a way of creating an iconic ...
(Date:6/26/2016)... Creek, Michigan (PRWEB) , ... June 26, 2016 , ... ... joined as sponsor of the 2016 Cereal Festival and World’s Longest Breakfast Table in ... in honor of the city’s history as home to some of the world’s leading ...
(Date:6/26/2016)... ... June 26, 2016 , ... PawPaws brand pet supplements owned by ... to enhance the health of felines. The formula is all-natural and is made from ... the PawPaws Cat Kidney Support Supplement Soft Chews are Astragalus Root Extract ...
(Date:6/26/2016)... (PRWEB) , ... June 26, 2016 , ... ... fertility once they have been diagnosed with endometriosis. These women need a treatment ... also require a comprehensive approach that can help for preservation of fertility and ...
(Date:6/25/2016)... TX (PRWEB) , ... June 25, 2016 , ... Austin ... of the American College of Mohs Surgery and to Dr. Russell Peckham for medical ... and highly effective treatment for skin cancer. The selective fellowship in Mohs Micrographic Surgery ...
Breaking Medicine News(10 mins):
(Date:6/24/2016)... 2016 Research and Markets ... Electronics 2015-2025: Applications, Technologies, Forecasts" report to ... In-Mold Electronics, Smart Skin, Structural Health Monitoring, Composite ... Structural electronics involves electronic and/or electrical components and ... dumb structures such as vehicle bodies or conformally ...
(Date:6/24/2016)... 2016 Research and Markets has announced ... Diagnostic Tests" report to their offering. ... The World Market for Companion Diagnostics covers ... Market analysis in the report includes the following: ... Diagnostic Kits) by Region (N. America, EU, ROW), 2015-2020 ...
(Date:6/24/2016)... , June 24, 2016  Arkis BioSciences, ... less invasive and more durable cerebrospinal fluid treatments, ... funding.  The Series-A funding is led by Innova ... Fund, and other private investors.  Arkis, new financing ... instrumentation and the market release of its in-licensed ...
Breaking Medicine Technology: