Navigation Links
To evade chemotherapy, some cancer cells mimic stem cells
Date:9/19/2007

ATLANTA - Anti-cancer treatments often effectively shrink the size of tumors, but some might have an opposite effect, actually expanding the small population of cancer stem cells believed to drive the disease, according to findings presented today in Atlanta, Georgia at the American Association for Cancer Researchs second International Conference on Molecular Diagnostics in Cancer Therapeutic Development.

Our experiments suggest that some treatments could be producing more cancer stem cells that then are capable of metastasizing, because these cells are trying to find a way to survive the therapy, said one of the studys investigators, Vasyl Vasko, M.D. Ph.D., a pathologist at the Uniformed Services University of the Health Sciences in Bethesda, Md.

This may help explain why the expression of stem cell markers has been associated with resistance to chemotherapy and radiation treatments and poor outcome for patients with cancers including prostate, breast and lung cancers, Dr. Vasko said. That tells us that understanding how to target these markers and these cells could prove useful in treating these cancers.

The cancer stem cell markers include Nanog and BMI1, both of which contribute to stem cells defining ability to renew themselves and differentiate into different cell types, Dr. Vasko said. These same molecules are found in embryonic stem cells.

Researchers have recently debated the notion that some therapies are not capable of eradicating cancer because they do not target the cancer stem cells responsible for tumor development. To test this hypothesis, Dr. Vasko, along with scientists from the CRTRC Institute for Drug Development in San Antonio and from the Johns Hopkins University, set out to measure both stem cells markers and tumor volume before and after treatment in a mouse model.

They selected a rare form of cancer, mesenchymal chondrosarcoma (MCS), which has not been well described and for which there is no effective treatment. The researchers first determined that Nanog and BMI1 stem cell markers were more highly expressed in metastatic tumors compared to primary tumors. This suggests that expression of the marker plays some role in development of metastasis, Dr. Vasko said.

They then applied various therapies - from VEGF inhibitors such as Avastin to the proteasome inhibitor Velcade - in mice implanted with human MSC, and analyzed the effects on tumors. Some of the treatments seemed to work, because they led to a dramatic decrease in the size of the tumors, Dr. Vasko said. But analysis of stem cell expression before and after treatment revealed that even as some anti-cancer treatments shrank tumors, they increased expression of Nanog and BMI1. These treatments were not enough to completely inhibit tumor growth, and the cancer stem cell markers were still present, Dr. Vasko said.

Use of the agents Velcade and Docetaxel led to the most significant increase in stem cell markers within the treated tumor, while ifosfamide and Avastin inhibited expression of the markers in this cancer subtype.

We hypothesize that the tumor escapes from chemotherapy by induction of stem cell marker expression, he said. The small number of cells that survive the treatment could then generate another tumor that metastasizes.

Dr. Vasko doesnt know how this happens, but theorizes that dying cells could secrete a lot of factors that induce expression of stem cell markers in other cancer cells. I think they are trying to survive and they use a mechanism from their experience of embryonic life.


'/>"/>

Contact: Greg Lester
267-646-0554
American Association for Cancer Research
Source:Eurekalert

Related medicine news :

1. Herpes Infects Cornea, Evades Immune Cells
2. Researchers Discover How Cancer Evades the Immune System
3. Radiation And Chemotherapy, A Better Option For Head And Neck Cancer
4. Watchdog to Be Set on Oral Chemotherapy, Warns Experts
5. Fibroids unlikely to Turn Cancerous
6. Virus Level could Predict Cervical Cancer Risk
7. Cancer Doctors Okays Controversial Prostate Therapy
8. Potential New Cancer Gene Identified
9. Vitamin B12 can help in detecting cancers
10. More Accurate "PROSTATE CANCER" Test can save Unnecessary Biopsies
11. Consensus on "Combination Therapy" for Breast Cancer
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:6/26/2016)... ... 2016 , ... On June 10-11, 2016, A Forever Recovery, a holistic treatment ... Longest Breakfast Table in Battle Creek, MI, where the rehabilitation facility is located. This ... of the world’s leading providers of cereal and other breakfast foods. Its residents often ...
(Date:6/26/2016)... , ... June 26, 2016 , ... ... once they have been diagnosed with endometriosis. These women need a treatment plan ... require a comprehensive approach that can help for preservation of fertility and ultimately ...
(Date:6/25/2016)... ... June 25, 2016 , ... "With 30 hand-drawn hand gesture animations, FCPX ... Austin - CEO of Pixel Film Studios. , ProHand Cartoon’s package transforms over ... Cut Pro X . Simply select a ProHand generator and drag it above media ...
(Date:6/25/2016)... ... ... Friday, June 10, Van Mitchell, Secretary of the Maryland Department of Health and Mental ... exemplary accomplishments in worksite health promotion. , The Wellness at Work Awards took place ... BWI Marriott in Linthicum Heights. iHire was one of 42 businesses to receive an ...
(Date:6/24/2016)... ... 24, 2016 , ... June 19, 2016 is World Sickle Cell Observance Day. ... the benefits of holistic treatments, Serenity Recovery Center of Marne, Michigan, has ... , Sickle Cell Disease (SCD) is a disorder of the red blood cells, which ...
Breaking Medicine News(10 mins):
(Date:6/24/2016)... Belgium , June 24, 2016 ... the appointment of Dr. Edward Futcher ... Non-Executive Director, effective June 23, 2016.Dr. Futcher was ... Nominations and Governance Committees.  As a non-executive member ... independent expertise and strategic counsel to VolitionRx in ...
(Date:6/23/2016)... , June 23, 2016 Any dentist who has ... of the current process. Many of them do not even ... technical difficulties and high laboratory costs involved. And those who ... it at such a high cost that the majority of ... Dr. Parsa Zadeh , founder of Dental Evolutions ...
(Date:6/23/2016)... , June 23, 2016 Research ... MEMS Devices Medical Market Analysis 2016 - Forecast to 2022" ... The report contains up to date financial data ... analysis. Assessment of major trends with potential impact on the ... analysis of market segmentation which comprises of sub markets, regional ...
Breaking Medicine Technology: