Showing posts with label GENETIC NEWS. Show all posts
Showing posts with label GENETIC NEWS. Show all posts

Tuesday, March 17, 2009

GENETIC NEWS

Balding Men May Get Help From Stem Cell, Gene Discoveries
Those with slick domes, thinning tops and receding hairlines may one day be helped by the discovery of genes that put people at risk for baldness and a stem cell that may replenish hair follicles.
Two studies released today in the journal Nature Genetics may help explain why some people lose their hair, and how they may eventually be able to grow it back, scientists from London- based GlaxoSmithKline Plc, the U.K. and Sweden said.

Hair loss affects about one in four Caucasian men before age 30. While drugs such as Johnson & Johnson's Rogaine and Merck & Co.'s Propecia can help hair regrow or prevent loss in some patients, they don't work for everyone. Treatments that target the DNA responsible may be more promising, said Tim Spector, who led the gene study.

``Early prediction before hair loss starts may lead to some interesting therapies that are more effective than treating late-stage hair loss,'' said Spector, a researcher in Kings College London's department of twin research and genetic epidemiology, in a statement.

Spector and colleagues analyzed the genes of 578 men in Switzerland with early-onset hair-loss, and compared them against those of 547 others who were retaining their hair. They then confirmed their findings against groups from the U.K., Iceland and the Netherlands, studying about 5,000 people in all.

Those with hair loss commonly shared the same variations of two genes that together made them seven times more likely to suffer baldness, researchers from Kings College London and GlaxoSmithKline Plc wrote in the journal Nature Genetics.

More Study Needed

The research associates the genes with hair loss, though further studies are needed to prove the connection. The genetic variations were also found in women, though the link wasn't statistically significant and more research is needed, the authors said. The study was partly funded by Glaxo.

In the stem cell study, researchers led by Viljar Jaks of Sweden's Karolinska Institute examined mouse hair follicles for signs of rapid growth. They found a protein, called Lgr5, on the surface of long-lived, active stem cells in hair cells; the same protein has been identified on stem cells in the intestine, they said in the study.

Cells bearing the Lgr5 marker were capable of maintaining hair follicles for as long as 14 months, the researchers said. In mouse studies, just a few of these cells were able to build an entire hair follicle, they said in the study.

The search for a cure for baldness began at least 3,000 years ago. Ancient Egyptians treated hair loss with fats from crocodiles, geese, lions, ibex, snake and hippopotamuses, according to the U.S.-based Coalition of Independent Hair Restoration Physicians.

`Balding Pattern'

Two of three men will be bald or have a ``balding pattern'' of hair loss by 60, according to the U.S. National Institutes of Health. The condition may be hereditary in more than 80 percent of cases, and has also been linked to maladies including heart disease and metabolic syndrome, the authors wrote.

Americans spent more than $115 million on hair transplant therapy last year, the authors said, and Merck's Propecia earned the Whitehouse Station, New Jersey-based drugmaker $405.4 million.

GENETIC NEWS

Testicle Stem Cells Become Bone, Muscle in German Experiments
Stem cells were isolated from the testicles of adult men and turned into bone, muscle, neural and other kinds of cells, German researchers said.
The advance, reported today in the journal Nature, may provide an alternative way to generate powerful stem cells that might be used to repair or replace damaged tissue in male patients with hard-to-treat diseases. Currently, scientists create stem cells by extracting them from embryos or genetically manipulating adult cells to make them pluripotent, or able to become many other cell types.

The use of testicle cells may also represent a new way to make lines of cells from a male with an inherited disease, for the purpose of studying his condition at the cellular level and testing drugs that might be effective in treating it.

The work by Thomas Skutella, director of the Center for Regenerative Biology and Medicine, in Tuebingen, Germany, produced a ``breathtaking result,'' said George Daley, a researcher at the Harvard Stem Cell Institute and at Children's Hospital Boston. While scientists had known that mouse testes give rise to other cells, he said, it wasn't clear that such cells could be isolated from humans.

``These are the only pluripotent cells present in adult human organisms,'' Skutella said. With this method, he said, ``you could take biopsies from people with Parkinson's or any kind of inherited disease'' and study the cells to learn how they function and respond to drugs.

The technique, if confirmed and improved, may allow researchers to sidestep ethical controversies that have dogged the field since University of Wisconsin scientists isolated stem cells from human embryos a decade ago.

Embryo Research Decried

Critics of embryonic research, including the Catholic Church, U.S. President George W. Bush and German lawmakers, view embryo destruction as immoral. Bush banned federal funding of research that uses newly destroyed embryos. German authorities went further, barring researchers there from creating embryonic stem cells, although they can import those derived in other countries, Skutella said.

Another method, developed two years ago by Japanese researchers, uses genes and viruses to reprogram adult skin cells so they become pluripotent and behave like embryonic stem cells. While this method avoids using embryos, the technique may trigger cancer or other unwanted effects. More recently researchers have begun to refine this method by eliminating viruses linked to cancer.

One advantage of Skutella's method is that if a man's own cells were used to make a therapy, they could be used to treat him without fear that his body would reject the cells. While he was able to coax the testicular stem cells to turn into a number of cell types, he wasn't able to make still other types, including heart cells.

Testicles Donated

Skutella and his colleagues obtained testicular tissue from various sources, including organ donors who had died. Others who supplied tissue were being treated for infertility or had their testicles removed in the course of surgery to change their sex to female or to treat prostate cancer.

The scientists used a complex process to identify and isolate a type of precursor cell that normally helps make sperm. They then concocted a chemical cocktail that allowed them to expand the stem cells.

GENETIC NEWS

Researchers Find Breast Cancer Gene, Spur Hope for New Drugs
Researchers discovered a gene involved in the spread of breast cancer, which may lead to new treatments for a disease that kills about 1 in 35 women.

The gene, called metadherin, may be crucial to cancer’s spread because it helps tumor cells stick to blood vessels in distant organs, researchers at Princeton University and the Cancer Institute of New Jersey found. The gene also makes tumors more resistant to drugs used to wipe out deadly cells.

Breast cancer is the most frequently diagnosed malignancy in U.S. women, excluding cancer of the skin, according to the American Cancer Society. Determining the genetic mechanism involved in the disease’s spread, known as metastasis, may help answer one of the biggest mysteries in cancer research.

“Inhibiting this gene in breast cancer patients will simultaneously achieve two important goals -- reduce the chance of recurrence and, at the same time, decrease the risk of metastatic dissemination,” Yibin Kang, an assistant professor of molecular biology at Princeton who led the research, said in a statement on the Cancer Institute’s Web site. “These are the two major reasons why breast cancer patients die from the disease.”

The finding, published today in Cancer Cell, is based on three years of work, using an approach that combines the emerging science of integrative genomics with the classical methods of clinical research and laboratory experiments, the authors said.

Quick Spread

Breast cancer is caused by a malignant tumor that develops from cells in the breast. The most common sign of breast cancer is a new lump or mass in the breast. Scientists once thought that breast cancer spread first to nearby tissue and underarm lymph nodes before reaching other parts of the body. They now believe cancer cells may break away from the primary tumor in the breast even when the disease is in an early stage.

After re-analyzing clinical breast cancer databases and tumor samples collected from patients, the researchers found an area of human chromosome 8 called 8q22 is repeated multiple times in the genomes of potentially lethal breast tumors. Most normal DNA sequences contain only two copies of a given gene, conveyed from the genomes of the male and female parents.

The researchers went on to discover that among a handful of genes in the 8q22 region, metadherin, also known as MTDH, is responsible for the aggressive behavior of some tumors. The scientists found that tumors which over-express MTDH are more likely to spread to the lungs, other vital organs and bones. These tumors were also found to be more resistant to some chemotherapy agents.

“By analyzing 250 breast tumor samples from patients, we found that this gene is amplified and over-expressed in over 30 to 40 percent of breast cancer cases,” Kang said. “This indicates that new drugs against metadherin may potentially benefit a large population of breast cancer patients.”

The work was funded by a Department of Defense Era of Hope Scholar Award and grants from the National Institutes of Health, the American Cancer Society, the Susan G. Komen Foundation and the New Jersey Commission on Cancer Research.