In cancer, an embryonic gene-silencing mechanism gone awry

October 04, 2012

There are some genes that are only activated in the very first days of an embryo's existence. Once they have accomplished their task, they are shut down forever, unlike most of our genes, which remain active throughout our lives. EPFL scientists have unveiled part of this strange mechanism. The same process, accidentally initiated later in life, could be responsible for many kinds of cancer. The discovery is described in a recent article in the journal Cell Reports.

The researchers identified a group of proteins that play a key role in this phenomenon. They bind to a DNA sequence near the gene, and substitute one DNA element for another, essentially "marking" the sequence. This phenomenon is known as "methylation." Once the marker is in place, the cellular machinery recognizes the sign and maintains the gene in a dormant state.

"It's an extremely elegant mechanism. The genes are needed right at the beginning of embryonic development, but rather than deactivate them every time a cell divides, the job is done in one fell swoop, once the genes are no longer required," explains EPFL professor Didier Trono, who co-authored the article. "This process is also involved in the control of viral sequences, which make up almost half of our genome, and must be inactivated very early in development."

This gene-silencing mechanism, which normally takes place in a several-day-old embryo, can also occur accidentally later in life. In many cancer cells, certain genes have been marked by methylation; they have been silenced. If, for example, the gene responsible for controlling cell division has been methylated, the consequences are all too easy to imagine. "The embryonic process, which is designed to silence certain genes, can be fortuitously reactivated, leading to the formation of tumor cells."

It is still not understood why the process stops after the first days of embryogenesis, even though many of the active proteins continue to be expressed in the cell, says Trono. "If we can figure out how this cellular clock works, then we would perhaps be able to understand how the mechanism is reactivated later, leading to the development of cancer."
-end-


Ecole Polytechnique Fédérale de Lausanne

Related Cancer Articles from Brightsurf:

New blood cancer treatment works by selectively interfering with cancer cell signalling
University of Alberta scientists have identified the mechanism of action behind a new type of precision cancer drug for blood cancers that is set for human trials, according to research published in Nature Communications.

UCI researchers uncover cancer cell vulnerabilities; may lead to better cancer therapies
A new University of California, Irvine-led study reveals a protein responsible for genetic changes resulting in a variety of cancers, may also be the key to more effective, targeted cancer therapy.

Breast cancer treatment costs highest among young women with metastic cancer
In a fight for their lives, young women, age 18-44, spend double the amount of older women to survive metastatic breast cancer, according to a large statewide study by the University of North Carolina at Chapel Hill.

Cancer mortality continues steady decline, driven by progress against lung cancer
The cancer death rate declined by 29% from 1991 to 2017, including a 2.2% drop from 2016 to 2017, the largest single-year drop in cancer mortality ever reported.

Stress in cervical cancer patients associated with higher risk of cancer-specific mortality
Psychological stress was associated with a higher risk of cancer-specific mortality in women diagnosed with cervical cancer.

Cancer-sniffing dogs 97% accurate in identifying lung cancer, according to study in JAOA
The next step will be to further fractionate the samples based on chemical and physical properties, presenting them back to the dogs until the specific biomarkers for each cancer are identified.

Moffitt Cancer Center researchers identify one way T cell function may fail in cancer
Moffitt Cancer Center researchers have discovered a mechanism by which one type of immune cell, CD8+ T cells, can become dysfunctional, impeding its ability to seek and kill cancer cells.

More cancer survivors, fewer cancer specialists point to challenge in meeting care needs
An aging population, a growing number of cancer survivors, and a projected shortage of cancer care providers will result in a challenge in delivering the care for cancer survivors in the United States if systemic changes are not made.

New cancer vaccine platform a potential tool for efficacious targeted cancer therapy
Researchers at the University of Helsinki have discovered a solution in the form of a cancer vaccine platform for improving the efficacy of oncolytic viruses used in cancer treatment.

American Cancer Society outlines blueprint for cancer control in the 21st century
The American Cancer Society is outlining its vision for cancer control in the decades ahead in a series of articles that forms the basis of a national cancer control plan.

Read More: Cancer News and Cancer Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.