Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Exploiting the stress response to detonate mitochondria in cancer cells

20.04.2011
Researchers at The Wistar Institute have found a new way to force cancer cells to self-destruct. Low doses of one anti-cancer drug currently in development, called Gamitrinib, sensitize tumor cells to a second drug, called TRAIL, also currently in clinical development as part of an anticancer regimen.

Their findings, published in the April issue of the Journal for Clinical Investigation, show how this combination approach kills tumor cells in both mouse models of glioblastoma and human glioblastoma cells. Glioblastomas are the most common and aggressive form of malignant brain cancer, affecting roughly 6 out of every 100,000 people. There is currently no effective treatment for glioblastoma, and patients rarely survive more than a year after diagnosis.

"We found that a low dose of Gamitrinib makes cancer cells susceptible to TRAIL, bypassing many of the mechanisms tumors use to survive," said senior author Dario Altieri, M.D., the Robert and Penny Fox Distinguished Professor at Wistar and director of The Wistar Institute Cancer Center. "Here we have found a new way to combine cancer therapies, one that could be applied to treating many types of cancer because both of these drugs target different mechanisms of tumor cell survival that revolve around mitochondria."

As commonly depicted in high school biology texts, mitochondria are the "powerhouses" of the cells, organelles whose main function is to turn sugar into useable energy. What is less commonly known is the role of mitochondria in programmed cell death, or apoptosis, the self-destruct system hardwired into every cell. Apoptosis evolved, in part, as a way for the body to react to extreme stress, a means to sacrifice damaged cells for the greater good of the organism. Cancer cells rely on the mitochondria to provide the energy rapidly-growing tumors need to survive, but find ways to block the signaling pathways that trigger apoptosis. Many researchers, including Altieri, have looked for ways to force tumor cells to hit this self-destruct switch.

Gamitrinib is a chemical inhibitor first developed by Altieri and his colleagues in 2009 at the University of Massachusetts. The drug binds to and inhibits Hsp90—Heat Shock Protein-90—a so-called chaperone protein that is highly active in mitochondria and other cellular organelles where it helps regulate and "rescue" other proteins, particularly in times of stress. Their previous studies have shown that Gamitrinib is effective in damaging tumor cell mitochondria, which can lead to cell death.

"When tumor cells are confronted with lower concentrations of Gamitrinib, they mount a stress-related defensive system, essentially eating damaged mitochondria and altering how genes are turned on and off to compensate for induced defects in the mitochondria," Altieri said. "This process naturally suppresses Nuclear Factor-kappa Beta, a protein that prevents apoptosis from happening. Ironically, it's this very defensive measure that we can exploit in killing tumor cells."

Nuclear Factor-kappa Beta (NF-êÂ) broadly promotes survival in tumors by halting the processes that lead to apoptosis. Altieri and his colleagues wanted to see if the suppression of NF-ê would provide an opportunity for TRAIL, a small engineered molecule that mimics the signals used to induce apoptosis.

In their experiments, researchers confirmed previous studies that showed how TRAIL alone did not affect glioblastoma in cell and animal models of the disease. TRAIL plus Gamitrinib, however, stimulated damage to mitochondria in tumor cells, which started a cascading series of reactions, culminating in cell death. Preclinical experiments conducted in mouse models of glioblastoma demonstrated that the combination did not cause any detectable toxic side effects.

According to Altieri, the fact that Gamitrinib and TRAIL are in clinical development already may help speed the process that could see eventual clinical trials of the two drugs together. "There is much preclinical work to be done, of course, but we are very interested in laying the groundwork now toward initial clinical trials," said Altieri.

Going forward, the researchers also plan to delve deeper into the cellular processes at work.

"I find the basic biology of this system fascinating, since here we show how mitochondria, which are the only organelles that have their own DNA, must communicate with the DNA in the cell's nucleus," Altieri said. "It is not a well-understood process by any means."

This study was supported by grants from the National Institutes of Health to Altieri, and a grant to co-author Markus D. Siegelin, M.D. from Deutsche Forschungsgemeinschaft (German Research Foundation).

The co-first authors of the study are Takehiko Dohi, Ph.D., currently a member of the Altieri lab at Wistar, and Siegelin, formerly a member of Altieri's previous laboratory at the University of Massachusetts Medical School and now a resident clinician at Columbia University. Contributors from the University of Massachusetts also include Christopher M. Raskett, Gregory M. Orlowski, Christine M. Powers, Candace A. Gilbert, Alonzo H. Ross, and Janet Plescia.

Greg Lester | EurekAlert!
Further information:
http://www.wistar.org

More articles from Life Sciences:

nachricht Toward a 'smart' patch that automatically delivers insulin when needed
18.01.2017 | American Chemical Society

nachricht 127 at one blow...
18.01.2017 | Stiftung Zoologisches Forschungsmuseum Alexander Koenig, Leibniz-Institut für Biodiversität der Tiere

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

A big nano boost for solar cells

18.01.2017 | Power and Electrical Engineering

Glass's off-kilter harmonies

18.01.2017 | Materials Sciences

Toward a 'smart' patch that automatically delivers insulin when needed

18.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>