Navigation Links
Deficiency in p53 anti-tumor protein delays DNA repair after radiation, Moffitt researchers say

Researchers at Moffitt Cancer Center have found that a deficiency in an important anti-tumor protein, p53, can slow or delay DNA repair after radiation treatment. They suggest that this is because p53 regulates the expression of two enzymes (JMJD2b and SUV39H1) that control the folding of DNA.

According to the researchers, p53 is highly inducible by radiation. Activation of p53 stabilizes chromosomes by promoting the repair of heterochromatin DNA, which controls the expression of nearby genes and ensures accurate distribution of chromosomes during cell division.

Their findings, which published online Feb. 4 in Oncogene, are significant because they shed light on the consequence of p53 deficiency that frequently occurs in tumors and further explain the function of p53 in the development of cancer.

Crucial to multicellular organisms, p53 is a tumor suppressor that regulates the cell cycle and helps prevent cancer by maintaining genetic stability and inhibiting gene mutation. But after irradiation, p53 deficiency results in abnormal levels of SUV39H1 and JMJD2b, enzymes that play a vital role in the structure of chromosomes, especially in DNA damage control and repair.

"Different tumor types have variable responses to ionizing radiation," explained study lead author Jiandong Chen, Ph.D., senior member of the Cancer Biology and Molecular Medicine Program at Moffitt. "Radiation therapy is more effective if tumors are defective in repairing damaged DNA. The p53 pathway is compromised to different degrees in all tumors, which may explain the fact that radiation often kills tumor cells more than normal cells."

In this study, the researchers worked with multiple cancer cell lines.

"We found that p53 activates JMJD2b and represses SUV39H1," Chen said. "Depletion of JMJD2b, or sustained expression of SUV39H1, delays the repair of heterochromatin DNA after ionizing radiation," explained Chen. "The DNA repair function of p53 may be particularly important in higher organisms because of the increased complexity of their genomes."

Although they note that there is no general consensus on the relationship between p53 mutation status and treatment response, in certain narrow settings such as breast cancer, p53 mutation is associated with favorable response to chemotherapy.

"We can conclude that the chromatin modifiers SUV39H1 and JMJD2b are important mediators of p53 function in maintaining the stability of highly repetitive DNA sequences, and developing new drugs that target these enzymes may benefit cancer therapy," the researchers wrote.


Contact: Kim Polacek
H. Lee Moffitt Cancer Center & Research Institute

Related medicine news :

1. Vitamin deficiency screening needed for refugees
2. Researches Vitamin D Deficiency & Using a More Natural Approach
3. Vitamin D deficiency linked to Type 1 diabetes
4. Health Issues Add to Risk of Vitamin D Deficiency, Study Says
5. Gestational exposure to urban air pollution linked to vitamin D deficiency in newborns
6. New Immune-Deficiency Illness Emerging in East Asia
7. Vitamin D deficiency and poorer lung function in asthmatic children treated with steroids
8. New targeted therapy for advanced prostate cancer shows anti-tumor activity in clinical trials
9. Same protein that fires up cancer-promoting Erk also blocks its activation
10. Researchers identify and block protein that interferes with appetite-suppressing hormone
11. Key bone marrow protein identified as potential new leukemia treatment target
Post Your Comments:
(Date:12/1/2015)... ... December 01, 2015 , ... The Multiple System Atrophy Coalition has announced ... Multiple System Atrophy (MSA) research, timed today to coincide with Giving Tuesday 2015, a ... including their ability to work and be productive, to do simple daily activities like ...
(Date:12/1/2015)... ... December 02, 2015 , ... ClinicoEconomics and Outcomes Research ... of treatment for osteoporosis ”. , As corresponding author Dr Ankita Modi says ... with osteoporosis. Based on a large US managed care database, women aged 55 ...
(Date:12/1/2015)... ... December 01, 2015 , ... According to an ... has filed a discrimination claim against the U.S. Department of Health and Human Services, ... Care Act (ACA) plans are breaking the clause in the law prohibiting the denial ...
(Date:12/1/2015)... ... December 01, 2015 , ... Dr. Paul Vitenas, one of the ... named by MedEsthetics magazine as the Best Single Physician Practice in the nation. Dr. ... elite aesthetic physicians honored by the industry publication. , Dr. Vitenas said he ...
(Date:12/1/2015)... York, NY (PRWEB) , ... December 01, 2015 ... ... epidemic in the 1980s we have seen vast improvements in scientific research and ... made significant strides, providing increased hope and relief to those affected by HIV/AIDS. ...
Breaking Medicine News(10 mins):
(Date:12/1/2015)... 2015   MabVax Therapeutics Holdings, Inc . (OTCQB: ... has filed an Investigational New Drug Application (IND) with ... Company,s lead fully human antibody product HuMab 5B1 as ... to initiate the Phase I clinical trial early in ... The planned Phase I trial will evaluate the ...
(Date:12/1/2015)... FRANCISCO , Dec. 1, 2015  InCarda Therapeutics, ... development and commercialization of therapies for cardiovascular conditions via ... a subsidiary business in Australia . ... trial in Australia in the ... leading investigators and medical centers in Adelaide ...
(Date:12/1/2015)... , Dec. 1, 2015  The migration ... to develop shared care plans that help patients ... care plans will be digitally enabled, incorporate care ... needs and desires. They will also allow all ... patient,s health journey is optimal. That is the ...
Breaking Medicine Technology: