Featured Research

from universities, journals, and other organizations

New Mode Of Action Discovered For Tamoxifen

Date:
February 3, 2004
Source:
University Of Iowa
Summary:
First used to treat breast cancer more than 30 years ago, tamoxifen now is one of the most widely used breast cancer therapies. University of Iowa researchers have discovered a new mode of action for tamoxifen, which could lead to better targeting of the therapy and possibly the development of new anti-cancer drugs.

IOWA CITY, Iowa -- First used to treat breast cancer more than 30 years ago, tamoxifen now is one of the most widely used breast cancer therapies. University of Iowa researchers have discovered a new mode of action for tamoxifen, which could lead to better targeting of the therapy and possibly the development of new anti-cancer drugs.

Related Articles


In breast tissue, tamoxifen acts as an anti-estrogen, meaning that it blocks the action of the hormone estrogen. Normal breast cells grow in response to estrogen in a controlled fashion. However, in breast cancer, this cell growth is out of control. Treatment with the anti-estrogen tamoxifen inhibits the uncontrolled cell growth and keeps cancer in check.

In a new study, which appears in the Jan. 15 issue of Clinical Cancer Research, researchers based at the Holden Comprehensive Cancer Center at the UI have identified another way that tamoxifen can prevent cancerous growth. The study indicates that tamoxifen treatment causes the re-expression of a tumor suppressor gene known as maspin.

Maspin protein has been shown to inhibit tumor invasion and metastasis, and in normal breast cells, maspin protein is abundant. However, in breast cancer, maspin gene expression is diminished or lost and tumors can form and spread unchecked. Previous studies have shown that reintroducing maspin into breast cancer cells, which have lost the gene expression, causes cancers to be less invasive.

The UI study showed that treatment with tamoxifen turned maspin expression back on in breast cancer cells that had lost the gene expression. The study suggests that one of tamoxifen's beneficial effects is due to its ability to turn maspin expression back on. Moreover, the researchers also found similar results in tissue samples from breast cancer patients who had been treated with tamoxifen.

"Looking at the tumor samples we found up-regulation of maspin in these samples too. That was further confirmation of what we saw in breast cancer cell lines," said Zhila Khalkhali-Ellis, Ph.D., UI associate research scientist and lead author of the study. "The importance of the study is that it demonstrates the ability of tamoxifen to up-regulate a tumor suppressor gene that has important consequences in inhibiting breast cancer invasion and metastasis. This has not been shown before. I think we can really use that information to improve treatment protocols."

Although tamoxifen has been proven clinically effective at treating and, in some cases, preventing breast cancer, this drug has two significant problems. Long-term use of tamoxifen, like many other cancer drugs, can lead to drug resistance and tamoxifen often causes unpleasant side effects. The finding that tamoxifen can up-regulate maspin expression may lead to the development of related drugs that can better target the maspin gene without producing side effects. The UI researchers also suggest that in light of this finding current tamoxifen treatment regimens should be reevaluated to monitor exactly how tamoxifen controls maspin expression and determine if different treatment protocols could maintain maspin expression while limiting drug resistance.

"In the best case scenario, longer exposure to tamoxifen results in a stronger re-expression of maspin for longer periods of time," said Mary Hendrix, Ph.D., the senior investigator on the study. "Following a tumor suppressor gene, such as maspin, offers an unique opportunity to track the efficacy of chemotherapy both during and after therapy."

In addition to Khalkhali-Ellis and Hendrix, the UI team also included Mohammad Vasef, M.D., associate professor (clinical) of pathology, who provided the breast tissue samples. Other researchers from Hendrix' laboratory involved in the study were Abby Christian, Dawn Kirschmann, Elijah Edwards, Maryam Rezaei-Thompson, Lynn Gruman, Richard Seftor and Laura Norwood.

The study was funded in part by the National Cancer Institute and the Marilyn Rozeboom Endowment.

University of Iowa Health Care describes the partnership between the UI Roy J. and Lucille A. Carver College of Medicine and UI Hospitals and Clinics and the patient care, medical education and research programs and services they provide. Visit UI Health Care online at http://www.uihealthcare.com.


Story Source:

The above story is based on materials provided by University Of Iowa. Note: Materials may be edited for content and length.


Cite This Page:

University Of Iowa. "New Mode Of Action Discovered For Tamoxifen." ScienceDaily. ScienceDaily, 3 February 2004. <www.sciencedaily.com/releases/2004/02/040202071310.htm>.
University Of Iowa. (2004, February 3). New Mode Of Action Discovered For Tamoxifen. ScienceDaily. Retrieved November 27, 2014 from www.sciencedaily.com/releases/2004/02/040202071310.htm
University Of Iowa. "New Mode Of Action Discovered For Tamoxifen." ScienceDaily. www.sciencedaily.com/releases/2004/02/040202071310.htm (accessed November 27, 2014).

Share This


More From ScienceDaily



More Health & Medicine News

Thursday, November 27, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Pet Dogs to Be Used in Anti-Ageing Trial

Pet Dogs to Be Used in Anti-Ageing Trial

Reuters - Innovations Video Online (Nov. 26, 2014) Researchers in the United States are preparing to discover whether a drug commonly used in human organ transplants can extend the lifespan and health quality of pet dogs. Video provided by Reuters
Powered by NewsLook.com
Today's Prostheses Are More Capable Than Ever

Today's Prostheses Are More Capable Than Ever

Newsy (Nov. 26, 2014) Advances in prosthetics are making replacement body parts stronger and more lifelike than they’ve ever been. Video provided by Newsy
Powered by NewsLook.com
From Popcorn To Vending Snacks: FDA Ups Calorie Count Rules

From Popcorn To Vending Snacks: FDA Ups Calorie Count Rules

Newsy (Nov. 25, 2014) The US FDA is announcing new calorie rules on Tuesday that will require everywhere from theaters to vending machines to include calorie counts. Video provided by Newsy
Powered by NewsLook.com
Daily Serving Of Yogurt Could Reduce Risk Of Type 2 Diabetes

Daily Serving Of Yogurt Could Reduce Risk Of Type 2 Diabetes

Newsy (Nov. 25, 2014) Need another reason to eat yogurt every day? Researchers now say it could reduce a person's risk of developing type 2 diabetes. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins