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:3/23/2017)... ... ... conference will prominently feature 150+ Hospital and Health System Executive Speakers including: , ... 43rd President of the United States of America: George W. Bush , ... the Ring: Sugar Ray Leonard , JD, Chairperson, McGuireWoods LLP: Amber McGraw Walsh ...
(Date:3/23/2017)... ... , ... Sharon Kleyne, host of the nationally syndicated radio program, The Sharon ... talked on her program about how she is looking forward to World Water Day ... important distinction. World Water Day, Kleyne pointed out, is an occasion for looking ahead ...
(Date:3/23/2017)... , ... March 23, 2017 , ... ... that help improve all aspects of people’s health and nutrition, announced its product ... products. , Natural Subsistence develops nutritional supplements that help people improve all ...
(Date:3/23/2017)... ... March 23, 2017 , ... Inflow IQ & Inflownomics ... serious so build on a solid foundation. As experts in dangerous situations the ... that is coming soon. Inflownomics deliver ripe, fresh, clean & refreshing knowledge systems that ...
(Date:3/23/2017)... ... March 23, 2017 , ... The American Board of Quality Assurance and Utilization ... ABQAURP’s dedication to Health Care Quality and Management and Patient Safety. , It is ... the association, but also to the Health Care Quality and Patient Safety movements. Diplomates ...
Breaking Medicine News(10 mins):
(Date:3/23/2017)... 2017  Drug diversion is a significant contributing ... overdoses. A new oral fluid monitoring test, announced ... reports more detailed and actionable information to clinicians ... therapy adherence, patient safety, and help to identify ... fluid Rx Evaluation (CORE) system is the first ...
(Date:3/23/2017)...  A new genetic test has been discovered ... who carry HLA-B*15:02 and who are ... deadly side effect of certain medications used to ... HLA-B*15:02 is strongly associated with life-threatening severe ... toxic epidermal necrolysis in patients treated with carbamazepine ...
(Date:3/23/2017)... ALBANY, New York , March 23, 2017 ... devices market exhibits a consolidated vendor landscape with the ... the overall market in 2015. These companies are ... Industries, Inc., Hygia Health Services, Inc., and VANGUARD ... global reprocessed medical devices market is witnessing the ...
Breaking Medicine Technology: