Sunday, April 11, 2010

Start/stop switch' for retroviruses found..

A researcher has discovered a previously unknown mechanism for silencing retroviruses, segments of genetic material that can lead to fatal mutations in a cell's DNA.

If ESET can be blocked, retroviruses would become dramatically more active, thus either killing the cancer cells hosting them or flagging them as targets for the immune system.

Leung, who was co-lead author with a graduate student at Kyoto University in Japan, has devoted his studies at UBC to the growing field of epigenetics -- changes to the genome that do not involve changes to the underlying genetic code. Such changes determine whether or not a gene is expressed.

Powerful new method allows scientists to probe gene activation

Researchers have developed a powerful new method to investigate the discrete steps necessary to turn on individual genes and examine how the process goes wrong in cancer and other diseases. The finding allows scientists to investigate the unfolding of DNA, a process required for gene activation.

Saturday, April 10, 2010

New Peptide Helps Cancer Drugs Break Into Tumors - ScienceNOW

New Peptide Helps Cancer Drugs Break Into Tumors - ScienceNOW

All cancer drugs share a problem: They penetrate just a few cells into the tumor. Now a team of biologists has identified a molecule that helps cancer treatments dive deep into tumors, at least in mice. The approach still needs to be tested in people, but if it pans out, it will circumvent one of the biggest challenges in the field. “This has huge implications for cancer therapy,” says David Cheresh, a tumor and vascular biologist at the University of California (UC), San Diego, who was not involved in the work.

Tumors keep drugs at bay in two ways. First, their vessels are not leaky enough to allow drugs inside. And second, they have high hydrostatic pressure. This means that fluid tends to flow away from tumors, not toward them, and that “any drug has to swim upstream, if you will,” says Erkki Ruoslahti, a cell and tumor biologist at the Sanford-Burnham Medical Research Institute in Santa Barbara, California. Last year, Ruoslahti and two scientists in his lab, Kazuki Sugahara and Tambet Teesalu, reported on a new peptide, a small molecule called iRGD, that seemed to do a good job of getting inside tumors when it was anchored to a cancer drug.

Drugs failing to get into tumors “is a huge problem for cancer in general,” especially when disease appears in the brain, which is even less accessible, says Zena Werb, a cell biologist at UC San Francisco. Werb cautions, however, that “it’s rather early” to tell how promising iRGD is. Cheresh points out that one risk is that the peptide could spawn new metastases by opening up tumor blood vessels and helping cancer cells to slip out. Still, they agree that if iRGD’s safety and effectiveness pan out, it could revolutionize cancer treatment for patients with all sorts of tumors. Ruoslahti is pushing it forward; he and his colleagues have filed patent applications on the peptide and are now in discussions with drug companies about testing it in humans.

Friday, April 9, 2010

Student uses skin as input for mobile devices

A combination of simple bio-acoustic sensors and some sophisticated machine learning makes it possible for people to use their fingers or forearms -- potentially, any part of their bodies -- as touchpads to control smart phones or other mobile devices.

The technology, called Skinput, was developed by Chris Harrison, a third-year Ph.D. student in Carnegie Mellon University's Human-Computer Interaction Institute (HCII), along with Desney Tan and Dan Morris of Microsoft Research. Harrison will describe the technology in a paper to be presented on April 12, at CHI 2010, the Association for Computing Machinery's annual Conference on Human Factors in Computing Systems in Atlanta, Ga.

New method to study key targets in Alzheimer's disease and prostate cancer

When designing a drug against a disease, chemists often used detailed plans of the proteins affected and against which the drugs must act. However, about a third of the proteins of our bodies have not yet been "photographed" because they generally vary in form, are in constant movements and have very little structure.This lack of "photographs" hinders the design of drugs against diseases involving proteins that are structurally "evasive," such as those in Alzheimer's disease and in prostate cancer that does not respond to conventional drugs.

With this new methodology, the group at IRB Barcelona, in collaboration with the University of Cambridge, will study why beta-amyloid plaques develop in Alzheimer's disease. They will examine the variety of forms that this protein adopts before and during accumulation. In another project, Salvatella will address the androgen receptor, the target protein in Kennedy's disease, a rare neurodegenerative disorder that causes muscular atrophy, as well in prostate cancer. "Oncologists are calling for new strategies to stop the growth of prostate tumours," explains Salvatella. The drugs currently available inhibit a part of the androgen receptor that is well known but in later stages of the disease these drugs can stop working. This protein has another important part that is intrinsically disordered and about which there is no structural information. "If our method is as reliable as we think, we could start to decipher the variety of structural forms that this other active part adopts in order to design drugs in the future."

Scientific breakthrough in combating HIV-1 virus


Scientists have made major breakthrough in understanding how the Vpu protein of HIV-1 interferes with the antiviral activity of Tetherin, a novel effector of innate immunity, and contributes to the spread of HIV-1 in humans.

In their article published in the open-access journal PLoS Pathogens, Dr. Cohen's team explains how the Vpu viral protein prevents the expression of Tetherin, a host factor inhibiting HIV-1 release, on the surface of infected cells.

Thus, if researchers manage to develop small molecules that prevent Vpu binding to Tetherin, this would restore one of the natural defence mechanisms that prevent the production, transmission and spread of HIV-1.

The study by Dr. Cohen's team allows a better understanding of the strategy used by HIV-1 to facilitate its transmission and its spread in humans. "Tetherin is a cellular protein that captures viruses forming at the surface of infected cells, thereby preventing viral transmission and spread. This antiviral protein, whose production is triggered by interferon, is an effector of the innate immune response against viral infections. However, viruses, and especially HIV-1, have evolved and developed mechanisms that antagonize this restriction factor. In fact, we have discovered how the Vpu protein neutralizes Tetherin, and as such stimulates HIV-1 production," stated Dr. Éric A. Cohen.