Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

’Virus chip’ detects new virus in prostate tumors

27.02.2006


UCSF and Cleveland Clinic scientists have discovered a new virus in human prostate tumors. The type of virus, closely related to viruses typically found in mice, has never been detected in humans. The virus’s link to human disease is still unclear, and more study is needed to determine the relationship between the virus and cancer, if any, the scientists say.



The discovery was made with the same DNA-hunting "virus chip" used to confirm the identity of the SARS virus three years ago.

While the genetics of prostate cancer are complex, one of the first genes implicated in the disease was RNASEL, a gene that serves as an important defense against viruses. Given the anti-viral role of this gene, some scientists have speculated that a virus could be involved in some types of prostate cancers in men with mutated RNASEL genes.


In the new study, the researchers discovered the novel virus far more often in human prostate tumors with two copies of the RNASEL gene mutation than in those with at least one normal copy.

"This is a virus that has never been seen in humans before," said Eric Klein, MD, a collaborator in the research and head of urologic oncology at the Glickman Urologic Institute of Cleveland Clinic. "This is consistent with previous epidemiologic and genetic research that has suggested that prostate cancer may result from chronic inflammation, perhaps as a response to infection."

"The power of the virus chip resides in its ability to simultaneously screen for all viruses, without preconceptions or bias," said Joe DeRisi, PhD, a Howard Hughes Medical Institute (HHMI) investigator at UCSF who developed the chip with colleagues in his lab. "In the case of these prostate tissues, no one would have suspected a virus of this class." DeRisi is a UCSF associate professor of biochemistry and co-leader of the study with Don Ganem, MD, also an HHMI investigator at UCSF and a professor of microbiology and immunology.

Klein reported the discovery today (February 24) at the American Society of Clinical Oncology (ASCO) prostate symposium in San Francisco. A full report of the discovery is in press in the journal PLoS Pathogens.

The new finding further validates the strategy of using the virus chip to discover previously unknown viruses and potentially uncover new viral causes for disease, the researchers say. While most other virus identification techniques require researchers to look for only a small number of candidates, the virus chip represents an unbiased search, since all known viruses are tested simultaneously.

The study is part of an on-going effort launched two years ago by DeRisi and Ganem at UCSF, using the chip, or microarray, to search for new viruses associated with a wide range of human disease. So far, the chip has been used to search for novel viruses in about 300 cases of respiratory infections and about 50 cases of meningitis, as well as a dozen or more cases of severe encephalitis, and hepatitis and leukemia.

Because the virus was probably originally acquired from another species, it is known as a xenotropic retrovirus – in this case, a xenotropic murine-like retrovirus, or XMRV. This is not the first virus of this family to be discovered, but it appears to be the first one found in humans, the scientists report.

The new virus is 96 percent identical to a class of known endogenous mouse retroviruses -- residents of the mouse genome. How the virus originally infected humans is unknown, Ganem says, though it was probably acquired from contact with rodents. It is extremely unlikely, however, that contact with mice was responsible for the virus detected in prostate tumors in the study. More likely, some form of human-to-human transmission is involved, but like many intriguing questions about the new virus’s biology, the answer is not yet known, he says.

In the study, researchers examined tissue samples of 86 prostate cancer patients whose prostates had been surgically removed. Among the 20 prostate tumor samples from men with mutations in both copies of their RNASEL viral defense gene, eight of them, or 40 percent, contained the virus, while the virus was found in only one of 66 tumors from men with at least one normal copy of the gene.

The researchers don’t know if the virus is unique to prostate tumors because this is the first tumor type they have studied using virus chip technology. As with most scientific discoveries, the identification of this virus in human prostate tissue prompts many more questions than it answers, they emphasize.

"A hit on the array is not the end of the project; it’s the beginning," Ganem says. "Pathogen discovery is really hard work." The team intends to carry out epidemiology studies to determine how widespread the virus is, how it is transmitted, and whether it causes any of the prostate tumors, or any other disease.

The gene-hunting technique DeRisi and Ganem call the Virochip is designed to identify any virus sample by comparing its DNA or RNA to more than 20,000 snippets of genetic material derived from all known viruses -- found in humans, animals, plants, fungi and bacteria. The chip draws on computer chip technology, computation and bioinformatics, but in essence it is a simple 3 x 1 inch glass microscope slide. Onto the slide the scientists robotically deposit 10 to 12 different DNA sequences from all known viruses.

Each sample appears as a microscopic dot, about a tenth of a millimeter in diameter –giving it the name micoroarray. Researchers then wash fluorescently tagged DNA from a sample of interest over the slide, and wherever the two sets of nucleic acid match up, they anneal to each other. The slide is then rinsed and visualized with a scanning laser microscope. The dots that have found a match glow with fluorescent light.

Wallace Ravven | EurekAlert!
Further information:
http://www.ucsf.edu

More articles from Life Sciences:

nachricht Symbiotic bacteria: from hitchhiker to beetle bodyguard
28.04.2017 | Johannes Gutenberg-Universität Mainz

nachricht Nose2Brain – Better Therapy for Multiple Sclerosis
28.04.2017 | Fraunhofer-Institut für Grenzflächen- und Bioverfahrenstechnik IGB

All articles from Life Sciences >>>

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

Fighting drug resistant tuberculosis – InfectoGnostics meets MYCO-NET² partners in Peru

28.04.2017 | 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

 
Latest News

Wireless power can drive tiny electronic devices in the GI tract

28.04.2017 | Medical Engineering

Ice cave in Transylvania yields window into region's past

28.04.2017 | Earth Sciences

Nose2Brain – Better Therapy for Multiple Sclerosis

28.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>