Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

How cancer cells lose their (circadian) rhythm

11.05.2010
Immortality and uncontrolled cell division are the fundamental differences between cancer cells and normal cells.
A widely held explanation for these differences is that the biological clocks in cancer cells are damaged and can’t regulate cell division in the fashion that they do in normal cells.

This assumption is challenged by the results of the first experiment that has continuously monitored variations in the rate of cell division of cultured mammalian cells for extended periods. The results are reported this week in a paper published in the online Early Edition of the Proceedings of the National Academy of Sciences.

The experiment discovered that one line of immortal cells have functioning biological clocks but their internal clocks have no effect on the rate at which they divide and grow. (Immortal cells have the same basic properties as cancer cells but are created in the laboratory where they are used for a wide variety of purposes.)

“The current assumption has been that the biological clocks in cancer cells have been disabled,” says Julie Pendergast, a research associate who participated in the study. “We determined that the immortalized cells in our experiment had functioning biological clocks but these clocks don’t control the process of cell division. That is the paradigm-shifting aspect of our study.”

If confirmed by follow-up studies, this insight could aid in the development of new cancer therapies.

“This strengthens the possibility that the biological clock pathway could be an effective target for anti-cancer drugs,” says Shin Yamazaki, the research professor of biological sciences at Vanderbilt who directed the project. “For example, if a drug could be found that restores the control of the biological clock over cancer cell division, it could reduce tumor growth.”

Biologists have observed that cell division in normal cells in species ranging from unicellular organisms to humans peaks at specific times of the day and consider this as indirect evidence that the process is regulated by their internal biological clocks. Cells in the human mouth, for example, tend to divide in the evening, just before nightfall.

“There is a general evolutionary explanation for this,” says Pendergast. “Ultraviolet light is one of the primary causes of mutations. Cells are particularly vulnerable to mutations during cell division. So organisms with cells that divide at night have a selective advantage.”

In addition, there has been a considerable amount of indirect evidence that mitosis (division) in cancer cells is not under 24-hour control. For example, “experiments have found that cells turn cancerous when certain circadian clock genes have been knocked out,” says Yamazaki. The results of other experiments that have periodically sampled cancer cell division rates also support this possibility.

Yamazaki designed and built a special system to monitor cell division in real time. He and his colleagues designed a special “reporter” molecule incorporating a gene that produces an enzyme that makes green light. They figured out how to insert this reporter into a cell’s genome so that it produces the luminescent enzyme when the cell divides. This allows them to use a camera to continuously measure variations in the rate of cell division over long periods of time.

For the current experiment, the researchers inserted their special reporter into immortalized rat fibroblasts formed from connective tissue taken from rats. They selected this cell line because it was known to have working circadian clocks.

They have obtained consistent results in preliminary studies of lung cancer cells.

The other participants in the study were Professor Yoshihiro Ohmiya at the Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan and post-doctoral researcher Mijung Yeom, now at the Acupuncture and Meridian Science Research Center, Kyung Hee University in Seoul, South Korea.

The research was supported by funds from the National Institutes of Health, Research Foundation for Opto-Science and Technology, the NEDO Project and Takeda Science Foundation.

For more news about Vanderbilt, visit the Vanderbilt News Service homepage on the Internet at www.vanderbilt.edu/News.

David F. Salisbury | Vanderbilt University
Further information:
http://www.vanderbilt.edu
http://www.vanderbilt.edu/exploration/stories/cancerrhythm.html

More articles from Life Sciences:

nachricht Decoding the genome's cryptic language
27.02.2017 | University of California - San Diego

nachricht New risk factors for anxiety disorders
24.02.2017 | Julius-Maximilians-Universität Würzburg

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Safe glide at total engine failure with ELA-inside

On January 15, 2009, Chesley B. Sullenberger was celebrated world-wide: after the two engines had failed due to bird strike, he and his flight crew succeeded after a glide flight with an Airbus A320 in ditching on the Hudson River. All 155 people on board were saved.

On January 15, 2009, Chesley B. Sullenberger was celebrated world-wide: after the two engines had failed due to bird strike, he and his flight crew succeeded...

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

New pop-up strategy inspired by cuts, not folds

27.02.2017 | Materials Sciences

Sandia uses confined nanoparticles to improve hydrogen storage materials performance

27.02.2017 | Interdisciplinary Research

Decoding the genome's cryptic language

27.02.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>