Featured Research

from universities, journals, and other organizations

Human Cells Secrete Cancer-killing Protein

Date:
July 27, 2009
Source:
University of Kentucky
Summary:
The tumor-suppressor protein Par-4 is secreted by human and rodent cells and activates a novel extrinsic pathway involving cell surface GRP78 receptor for induction of apoptosis, researchers have found.

Human cells are able to secrete a cancer-killing protein, scientists at the University of Kentucky's Markey Cancer Center have found.

Researchers led by Vivek Rangnekar, UK professor of radiation medicine, have determined that the tumor-suppressor protein Par-4, initially thought to be active only within cells expressing the Par-4 gene, is in fact secreted by most human and rodent cells and can target large numbers of cancer cells by binding to receptors on the cell surface.

This discovery, published today in the leading journal Cell, makes Par-4 a very attractive molecule for future research aimed at developing new cancer treatments.

"It was a pleasant surprise, when we noticed that Par-4 protein is secreted by cells," Rangnekar said. "This new finding means it is not necessary to make genetic modifications, or to employ recombinant viruses, to deliver the Par-4 gene to cancer cells, and it significantly expands the potential applications of Par-4 to selectively kill cancer cells."

Funded by several grants from the National Institutes of Health, Rangnekar's study found that when the Par-4 molecule binds to its receptor GRP78 on the surface of a tumor cell, it triggers a biological process called apoptosis or "cell suicide." Consistent with previous research by Rangnekar's laboratory with intracellular Par-4, the newly discovered secreted Par-4 acts selectively against cancer cells, leaving healthy cells unharmed. Few other molecules are known to exhibit such selectivity.

One molecule, known as TRAIL, also exerts cancer-cell-specific effects. However, Rangnekar's most recent study discovered that apoptosis inducible by TRAIL is dependent upon extracellular Par-4 signaling via cell surface GRP78. Thus, the researchers conclude, Par-4 activates a novel pathway involving cell surface GRP78 receptor for induction of apoptosis. In other words, without Par-4, TRAIL lacks the ability to cause "cell suicide."

Rangnekar first discovered the Par-4 gene in 1993. In 2007, Rangnekar's team introduced the gene into a mouse embryo, creating a cancer-resistant "supermouse" that did not develop tumors. In fact, the mice possessing Par-4 actually live a few months longer than lab mice without the gene, indicating that Par-4 mice have no toxic side effects.

While Par-4 is not necessarily a "magic bullet" — it does not target every type of cancer cell — Rangnekar says it could play a major role in developing new combination treatment modalities for cancer patients. His hope is that the next generation of treatments will be even more effective than conventional treatments available today, with fewer and less severe side effects.

"I look at this research from the standpoint of how it can be developed to benefit the cancer patient, and that's what keeps us focused," Rangnekar said, discussing the potential of Par-4 in 2007. "The pain that cancer patients go through — not just from the disease, but also from the treatment — is excruciating. If you can treat the cancer and not harm the patient, that's a major breakthrough."

Rangnekar holds the Alfred Cohen, M.D., Endowed Chair in Oncology Research at the UK College of Medicine.


Story Source:

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


Cite This Page:

University of Kentucky. "Human Cells Secrete Cancer-killing Protein." ScienceDaily. ScienceDaily, 27 July 2009. <www.sciencedaily.com/releases/2009/07/090723150826.htm>.
University of Kentucky. (2009, July 27). Human Cells Secrete Cancer-killing Protein. ScienceDaily. Retrieved August 30, 2014 from www.sciencedaily.com/releases/2009/07/090723150826.htm
University of Kentucky. "Human Cells Secrete Cancer-killing Protein." ScienceDaily. www.sciencedaily.com/releases/2009/07/090723150826.htm (accessed August 30, 2014).

Share This




More Health & Medicine News

Saturday, August 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

We've Got Mites Living In Our Faces And So Do You

We've Got Mites Living In Our Faces And So Do You

Newsy (Aug. 30, 2014) A new study suggests 100 percent of adult humans (those over 18 years of age) have Demodex mites living in their faces. Video provided by Newsy
Powered by NewsLook.com
Liberia Continues Fight Against Ebola

Liberia Continues Fight Against Ebola

AFP (Aug. 30, 2014) Authorities in Liberia try to stem the spread of the Ebola epidemic by raising awareness and setting up sanitation units for people to wash their hands. Duration: 00:41 Video provided by AFP
Powered by NewsLook.com
California Passes 'yes-Means-Yes' Campus Sexual Assault Bill

California Passes 'yes-Means-Yes' Campus Sexual Assault Bill

Reuters - US Online Video (Aug. 30, 2014) California lawmakers pass a bill requiring universities to adopt "affirmative consent" language in their definitions of consensual sex, part of a nationwide drive to curb sexual assault on campuses. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
3 Things To Know About The Ebola Outbreak's Progression

3 Things To Know About The Ebola Outbreak's Progression

Newsy (Aug. 29, 2014) Here are three things you need to know about the deadly Ebola outbreak's progression this week. 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:
from the past week

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