Featured Research

from universities, journals, and other organizations

Less is more for common cancer drug, study suggests

Date:
October 1, 2011
Source:
University of Georgia
Summary:
Scientists have found that smaller, less toxic amounts of chemotherapy medicine given frequently to mice with human prostate cancer noticeably slowed tumor growth.

University of Georgia scientists have found that smaller, less toxic amounts of chemotherapy medicine given frequently to mice with human prostate cancer noticeably slowed tumor growth. The mice suffered fewer side effects compared with traditional cancer treatment relying on heavy doses that can cause hair and bone loss.

While chemotherapy given repeatedly in small portions, called metronomic dosing, is not new, the study's authors say that the dosing appears to alter the cellular activity of the drug topotecan. This finding offers promising new ways to use topotecan-which is widely used and approved by the Food and Drug Administration for cervical and other cancers-to combat slowly growing prostate tumors. The findings appear this month in the journal Cancer Biology and Therapy.

"At these lower doses, there isn't enough topotecan to follow a classic cell death pathway," said study co-author Robert D. Arnold, a Georgia Cancer Coalition Distinguished Scholar and assistant professor in the UGA College of Pharmacy. "Our research suggests that metronomic dosing altered topotecan's behavior."

Scientists have known that topotecan given to patients in large, traditional doses kills cancer cells by deactivating proteins known as enzymes that are necessary for cell growth, Arnold explained. By contrast, metronomic dosing of topotecan prevents new blood vessels-which are necessary for growth-from forming in the tumor. Arnold and his colleagues discovered that topotecan did not change the amount of blood vessels formed, but significantly decreased tumor size and altered genes critical for controlling cell growth.

Brian S. Cummings, a co-author and associate professor at the pharmacy college, compared topotecan's process of killing tumor cells to the everyday task of running an errand.

"Let's assume you're going to go to the grocery store and you could walk, ride your bike or take the car," he said. "Those are different mechanisms of action. You will still get to the same place."

He added that researchers try to determine which pathway, or transportation choice, cells take after different amounts of exposure to topotecan. Their results suggest that when topotecan is given frequently in low doses, the drug could be changing the type of genes turned on in the tumor. These changes may be related to the structure or architecture of a gene-not a change in gene sequence. Such changes could be considered epigenetic, but more research is needed, Arnold said.

The study suggests that metronomic dosing of topotecan can reduce prostate cancer growth at drug concentrations far below those that can be toxic to healthy cells in the body.

Given the limited treatment options for late-stage prostate cancer and clinical use of topotecan, new clinical trials could occur in the near future, Arnold said. The same research team is now studying the dosing effects of topotecan in breast cancer models.

Co-authors of the study are Ibrahim Aljuffali, currently at King Saud University, Saudi Arabia, and Jason Mock, Leah Costyn, Ha Nguyen and Dr. Tamas Nagy of UGA.

The research was funded in part by an UGA Faculty Research Grant, an Interdisciplinary Toxicology Program equipment grant, a Georgia Cancer Coalition Distinguished Scholar grant, as well as a King Saud University fellowship and graduate stipend support from the National Institutes of Health.


Story Source:

The above story is based on materials provided by University of Georgia. The original article was written by Kathleen Raven. Note: Materials may be edited for content and length.


Cite This Page:

University of Georgia. "Less is more for common cancer drug, study suggests." ScienceDaily. ScienceDaily, 1 October 2011. <www.sciencedaily.com/releases/2011/09/110930195141.htm>.
University of Georgia. (2011, October 1). Less is more for common cancer drug, study suggests. ScienceDaily. Retrieved October 20, 2014 from www.sciencedaily.com/releases/2011/09/110930195141.htm
University of Georgia. "Less is more for common cancer drug, study suggests." ScienceDaily. www.sciencedaily.com/releases/2011/09/110930195141.htm (accessed October 20, 2014).

Share This



More Health & Medicine News

Monday, October 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

How Nigeria Beat Its Ebola Outbreak

How Nigeria Beat Its Ebola Outbreak

Newsy (Oct. 20, 2014) The World Health Organization has declared Nigeria free of Ebola. Health experts credit a bit of luck and the government's initial response. Video provided by Newsy
Powered by NewsLook.com
Another Study Suggests Viagra Is Good For The Heart

Another Study Suggests Viagra Is Good For The Heart

Newsy (Oct. 20, 2014) An ingredient in erectile-dysfunction medications such as Viagra could improve heart function. Perhaps not surprising, given Viagra's history. Video provided by Newsy
Powered by NewsLook.com
Ebola Worries End for Dozens on U.S. Watch Lists

Ebola Worries End for Dozens on U.S. Watch Lists

Reuters - US Online Video (Oct. 20, 2014) Forty-three people who had contact with Thomas Eric Duncan, the first person diagnosed with Ebola in the U.S., were cleared overnight of twice-daily monitoring after 21 days of showing no symptoms. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com
Fauci: Ebola Protocols to Focus on Training

Fauci: Ebola Protocols to Focus on Training

AP (Oct. 20, 2014) Dr. Anthony Fauci, head of the National Institute of Allergy and Infectious Diseases, says he expects revised CDC protocols on Ebola to focus on training, observation and ensuring health care workers are more protected. (Oct. 20) Video provided by AP
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