Navigation Links
How cancer cells loose their (Circadian) rhythm
Date:5/10/2010

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 research associate Julie Pendergast who participated in the study. "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.


'/>"/>

Contact: David F. Salisbury
david.salisbury@vanderbilt.edu
615-343-6803
Vanderbilt University
Source:Eurekalert  

Related medicine news :

1. Researchers discover new way to rescue treatment sensitivity of breast cancer cells
2. U.S. Cancer Costs Double in Two Decades
3. Jenny McCarthy - Actress, Activist, and Model - Dedicates bforacure's ‘breasts are beautiful' to Help Raise Money for Breast Cancer Charities
4. Medical costs of cancer have nearly doubled over the past 2 decades
5. Kidney removal does not prolong the lives of elderly patients with localized kidney cancer
6. Coffee and soft drinks have little or no association with colon cancer risk
7. No Link Between Coffee, Sodas and Colon Cancer
8. Tumor Cells in Blood Affect Breast Cancer Survival
9. Cancer Society Says U.S. Report Failed to Prove Health Risks
10. Simple Test May Identify Breast Cancer Subtypes
11. Interesting stories at the IMPAKT Breast Cancer Conference
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
How cancer cells loose their (Circadian) rhythm
(Date:6/27/2016)... ... June 27, 2016 , ... The OSHA ... Training Institute Education Center headquartered in Northern California, has issued an important reminder ... at their worksites. Employers with workers exposed to high temperatures should establish ...
(Date:6/27/2016)... ... ... "FCPX editors can now reveal their media with growing colorful split screen ... - CEO of Pixel Film Studios. , ProSlice Color brings the split screens ... reveal the media of their split screens with growing colorful panels. , ProSlice Color ...
(Date:6/27/2016)... ... June 27, 2016 , ... TherapySites, the leading ... with Tennessee Counseling Association. This new relationship allows TherapySites to continue ... Association, adding exclusive benefits and promotional offers. , "TCA is extremely excited about ...
(Date:6/27/2016)... ... June 27, 2016 , ... ... today announced its strategic partnership with Connance, a healthcare industry leader providing ... companies’ proven, proprietary technology combine to provide health systems, hospitals and ambulatory ...
(Date:6/27/2016)... ... June 27, 2016 , ... ... to revolutionize the emergency ambulance transport experience for the millions of people who ... Uber has disrupted the taxi industry through the use of technology. Now, SmartEMS ...
Breaking Medicine News(10 mins):
(Date:6/26/2016)... One of Australia,s successful biotechnology scientists, Dr ... biotechnology company, Noxopharm Limited [ABN 50 608 966 123] ("Noxopharm"). Noxopharm ... on the ASX. Noxopharm is a clinic-ready company with ... 1 clinical study later this year. ... problems facing cancer patients - the ability of cancers to become ...
(Date:6/26/2016)... -- Jazz Pharmaceuticals plc (Nasdaq: JAZZ ) ... Improvements Act of 1976, as amended ("HSR"), with respect ... Nasdaq: CPXX ) expired effective June 24, ... As previously announced on May 31, 2016, Jazz Pharmaceuticals ... which Jazz Pharmaceuticals has commenced a tender offer for ...
(Date:6/26/2016)... OTTAWA, Ontario , June 27, 2016  VMS ... the Company,s Board will take whatever measures required to ... the Company,s stock which is currently listed on the ... S Wexler, Company Chairman and CEO, "We are seeing ... be difficult to understand, not only by the Company, ...
Breaking Medicine Technology: