Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Bacterial protein kills tumors

28.10.2002


New weapon in the fight against cancer?



The use of live bacteria to treat cancer goes back a hundred years. But while the therapy can sometimes shrink tumors, the treatment usually leads to toxicity, limiting its value in medicine.

Now, researchers at the University of Illinois at Chicago have isolated a protein secreted by bacteria that kills cancer cells but appears to have no harmful side effects. Tested in mice injected with human melanomas, the protein shrank the malignancies, but, in contrast with other studies using whole bacteria, caused no deaths or adverse reactions in the laboratory animals.


"Bacterial proteins could well be a new weapon in the war against cancer," said Ananda Chakrabarty, distinguished professor of microbiology and immunology and one of the study’s investigators.

Results of the three-year-long study are published in the October 29 issue of the Proceedings of the National Academy of Sciences.

Oddly, the protein the researchers isolated is a well-studied molecule called azurin that is involved in the everyday process cells use to generate energy. This is the first report, however, that azurin is an effective anticancer agent.

The protein was isolated from the growth medium of Pseudomonas aeruginosa, a bacterium that is often resistant to antibiotics and causes serious respiratory infections in people who are particularly susceptible, such as patients with cystic fibrosis or severe burns. The bacterium protects itself from destruction by killing macrophages, the immune system’s first line of attack against a foreign body.

In the UIC study, specially-bred immunodeficient mice implanted with human melanoma were treated with half a milligram of azurin daily for 22 days. At the conclusion of the trial, the average size of the tumors in these mice was 60 percent smaller than those in untreated mice. None of the mice showed signs of illness or loss of weight.

The researchers said that azurin appears to work by stabilizing the p53 protein, a product of the p53 gene, known as a tumor suppressor because it prevents the formation of cancers through a cascade of molecular events that either stops cells from dividing or induces a process called programmed cell death. Normally, the p53 protein is short-lived, surviving just a few minutes in the cell before degrading. But azurin winds its way into the nucleus of the tumor cell, where it binds to the p53 protein and protects it from degradation, thus raising its level within the cell.

According to Dr. Tapas Das Gupta, a co-investigator and head of surgical oncology at UIC, preliminary data show that azurin kills several types of cancer cells, including breast and colon cancer.

"These results suggest that azurin could be a useful anticancer agent not just for melanoma but for different kinds of tumors," Das Gupta said. But he cautioned that extensive studies are needed to confirm the inital laboratory results.

The first observation that bacteria can thwart tumors was made in 1893 by New York physician William Coley, who found that bone cancer patients who contracted bacterial infections survived longer.

Much more recently, researchers at Johns Hopkins University used anaerobic bacteria, bacteria that thrive without oxygen, to destroy the hard cores of tumors. Radiation and chemotherapy are ineffective in these areas because they lack blood and oxygen. In the Hopkins studies, whole "de-fanged" bacteria were used. But although their tumors shrank, a large proportion of the experimental mice died, presumably because of toxins released either by the bacteria or the dying cancer cells.

"Our research suggests we can achieve a therapeutic outcome using bacterial proteins, without the toxicity associated with live bacteria," Chakrabarty said.


Other authors of the study were UIC researchers Tohru Yamada, Masatoshi Goto, Vasu Punj, Olga Zaborina, Mei Ling Chen, Kazuhide Kimbara, Dibyen Majumdar and Elizabeth Cunningham.

The study was supported by grants from the National Institute of Environmental Health Sciences, the National Institute of Allergy and Infectious Diseases and the National Cancer Institute.

Sharon Butler | EurekAlert!
Further information:
http://www.uic.edu

More articles from Health and Medicine:

nachricht New High-Performance Center Translational Medical Engineering
26.04.2017 | Fraunhofer ITEM

nachricht A promising target for kidney fibrosis
21.04.2017 | Brigham and Women's Hospital

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

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

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

Scientist invents way to trigger artificial photosynthesis to clean air

26.04.2017 | Materials Sciences

Ammonium nitrogen input increases the synthesis of anticarcinogenic compounds in broccoli

26.04.2017 | Agricultural and Forestry Science

SwRI-led team discovers lull in Mars' giant impact history

26.04.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>