Chaperone enzyme provides new target for cancer treatments

Jan 18, 2011

UNC scientists who study how cells repair damage from environmental factors like sunlight and cigarette smoke have discovered how a "chaperone" enzyme plays a key role in cells' ability to tolerate the DNA damage that leads to cancer and other diseases.

The enzyme, known as Rad18, detects a protein called DNA polymerase eta (Pol eta) and accompanies it to the sites of sunlight-induced DNA damage, enabling accurate repair. When Pol eta is not present, alternative error-prone polymerases take its place – a process that leads to DNA mutations often found in cancer cells.

In one known example, faulty DNA repair due to Pol eta- deficiency is responsible for the genetic disease xeroderma pigmentosum-variant, which makes patients extremely susceptible to skin cancers caused by exposure to sunlight. However, scientists did not know how the cells selected the correct DNA Polymerase for error-free repair of each type of DNA damage.

"We found that the mechanism that promotes the 'chaperone' enzyme to recruit Pol eta to sites of is managed by another signaling termed 'Cdc7' which we know is essential to normal regulation of the cellular lifecycle," said lead author Cyrus Vaziri, PhD, who is an associate professor of pathology and laboratory medicine and member of UNC Lineberger Comprehensive Cancer Center. Thus cells employ Cdc7 to ensure accurate DNA repair during the stage of their lifecycle that is most vulnerable to cancer-causing mutations.

The study was published in November in the Journal of Cell Biology.

According to Vaziri, the dual role that Cdc7 plays in the cell lifecycle and DNA repair offers a promising target for potential cancer therapies.

"We know that cancer have high levels of Cdc7 activity and can evade some DNA-damaging therapies such as cis-Platinum through Rad18 and Pol eta activity. We may be able to target this pathway in platinum-resistant tumors to prevent DNA repair and enhance cell killing by platinating agents," he said.

Explore further: Researchers find protein necessary for fertility performs different roles in sperm, eggs

Related Stories

Recommended for you

In a role reversal, RNAs proofread themselves

22 hours ago

Building a protein is a lot like a game of telephone: information is passed along from one messenger to another, creating the potential for errors every step of the way. There are separate, specialized enzymatic ...

Growing functioning brain tissue in 3D

Jan 29, 2015

Researchers at the RIKEN Center for Developmental Biology in Japan have succeeded in inducing human embryonic stem cells to self-organize into a three-dimensional structure similar to the cerebellum, providing ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.