Featured Research

from universities, journals, and other organizations

Drug from Mediterranean weed kills tumor cells in mice

Date:
July 9, 2012
Source:
Johns Hopkins Medical Institutions
Summary:
Scientists have developed a novel anticancer drug designed to travel -- undetected by normal cells -- through the bloodstream until activated by specific cancer proteins. The drug, made from a weed-like plant, has been shown to destroy cancers and their direct blood supplies, acting like a "molecular grenade," and sparing healthy blood vessels and tissues.

Scientists at the Johns Hopkins Kimmel Cancer Center, working with Danish researchers, have developed a novel anticancer drug designed to travel -- undetected by normal cells -- through the bloodstream until activated by specific cancer proteins. The drug, made from a weedlike plant, has been shown to destroy cancers and their direct blood supplies, acting like a "molecular grenade," and sparing healthy blood vessels and tissues.

In laboratory studies, researchers said they found that a three-day course of the drug, called G202, reduced the size of human prostate tumors grown in mice by an average of 50 percent within 30 days. In a direct comparison, G202 outperformed the chemotherapy drug docetaxel, reducing seven of nine human prostate tumors in mice by more than 50 percent in 21 days. Docetaxel reduced one of eight human prostate tumors in mice by more than 50 percent in the same time period.

In a report June 27 in the journal Science Translational Medicine, the researchers also reported that G202 produced at least 50 percent regression in models of human breast cancer, kidney cancer and bladder cancer.

Based on these results, Johns Hopkins physicians have performed a phase I clinical trial to assess safety of the drug and have thus far treated 29 patients with advanced cancer. In addition to Johns Hopkins, the University of Wisconsin and the University of Texas-San Antonio are participating in the trial. A phase II trial to test the drug in patients with prostate cancer and liver cancer is planned.

The drug G202 is chemically derived from a weed called Thapsia garganica that grows naturally in the Mediterranean region. The plant makes a product, dubbed thapsigargin, that since the time of ancient Greece has been known to be toxic to animals. In Arab caravans, the plant was known as the "death carrot" because it would kill camels if they ate it, the researchers noted.

"Our goal was to try to re-engineer this very toxic natural plant product into a drug we might use to treat human cancer," says lead study author Samuel Denmeade, M.D., professor of oncology, urology, pharmacology and molecular sciences. "We achieved this by creating a format that requires modification by cells to release the active drug."

By disassembling thapsigargin and chemically modifying it, the researchers created a form that Denmeade likens to a hand grenade with an intact pin. The drug can be injected and can travel through the bloodstream until it finds the site of cancer cells and hits a protein called prostate-specific membrane antigen (PSMA). PSMA is released by cells lining tumors of the prostate and other areas, and in effect "pulls the pin" on G202, releasing cell-killing agents into the tumor and the blood vessels that feed it, as well as to other cells in the vicinity. Specifically, G202 blocks the function of a protein called the SERCA pump, a housekeeping protein necessary for cell survival that keeps the level of calcium in the cell at the correct level, the researchers report.

"The exciting thing is that the cancer itself is activating its own demise," says senior study author John Isaacs, Ph.D., professor of oncology, urology, chemical and biomedical engineering at Johns Hopkins.

Because the drug is targeted to the SERCA pump, which all cells need to stay alive, researchers say it will be difficult for tumor cells to become resistant to the drug, because they cannot stop making the protein.


Story Source:

The above story is based on materials provided by Johns Hopkins Medical Institutions. Note: Materials may be edited for content and length.


Journal Reference:

  1. S. R. Denmeade, A. M. Mhaka, D. M. Rosen, W. N. Brennen, S. Dalrymple, I. Dach, C. Olesen, B. Gurel, A. M. DeMarzo, G. Wilding, M. A. Carducci, C. A. Dionne, J. V. Moller, P. Nissen, S. B. Christensen, J. T. Isaacs. Engineering a Prostate-Specific Membrane Antigen-Activated Tumor Endothelial Cell Prodrug for Cancer Therapy. Science Translational Medicine, 2012; 4 (140): 140ra86 DOI: 10.1126/scitranslmed.3003886

Cite This Page:

Johns Hopkins Medical Institutions. "Drug from Mediterranean weed kills tumor cells in mice." ScienceDaily. ScienceDaily, 9 July 2012. <www.sciencedaily.com/releases/2012/07/120709155425.htm>.
Johns Hopkins Medical Institutions. (2012, July 9). Drug from Mediterranean weed kills tumor cells in mice. ScienceDaily. Retrieved September 23, 2014 from www.sciencedaily.com/releases/2012/07/120709155425.htm
Johns Hopkins Medical Institutions. "Drug from Mediterranean weed kills tumor cells in mice." ScienceDaily. www.sciencedaily.com/releases/2012/07/120709155425.htm (accessed September 23, 2014).

Share This



More Health & Medicine News

Tuesday, September 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Ebola Costs Keep Mounting

Ebola Costs Keep Mounting

Reuters - Business Video Online (Sep. 23, 2014) The WHO has warned up to 20,000 people could be infected with Ebola over the next few weeks. As Sonia Legg reports, the implications for the West African countries suffering from the disease are huge. Video provided by Reuters
Powered by NewsLook.com
Ebola Cases Could Reach 1.4 Million Within 4 Months

Ebola Cases Could Reach 1.4 Million Within 4 Months

Newsy (Sep. 23, 2014) Health officials warn that without further intervention, the number of Ebola cases in Liberia and Sierra Leone could reach 1.4 million by January. Video provided by Newsy
Powered by NewsLook.com
WHO: Ebola Cases to Triple in Weeks Without Drastic Action

WHO: Ebola Cases to Triple in Weeks Without Drastic Action

AFP (Sep. 23, 2014) The number of Ebola infections will triple to 20,000 by November, soaring by thousands every week if efforts to stop the outbreak are not stepped up radically, the WHO warned in a study on Tuesday. Duration: 01:01 Video provided by AFP
Powered by NewsLook.com
5 Ways Men Can Prevent Most Heart Attacks

5 Ways Men Can Prevent Most Heart Attacks

Newsy (Sep. 23, 2014) No surprise here: A recent study says men can reduce their risk of heart attack by maintaining a healthy lifestyle, which includes daily exercise. 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