U.S., Swedish and Japanese scientists say a double dose of a protein can double the risk a cancer-causing genetic mutation will trigger a colon tumor. Roughly 10 percent of people have this double protein, according to study leader Dr. Andrew Feinberg, of the Center for Epigenetics in Common Human Disease at Johns Hopkins in Baltimore. The study, published in Science, says mice engineered to have a double dose of insulin-like growth factor 2 -- IGF2 -- develop more so-called precursor cells within the lining of the colon than normal mice. When these mice also carried a colon-cancer-causing genetic mutation, they developed twice as many tumors as those with normal IGF2 levels.
EFFORT TO IDENTIFY ALZHEIMER'S GENES
U.S. researchers have initiated a study to identify genes that are involved in the development of Alzheimer's disease. Using cutting edge technology, researchers at Translational Genomics Research Institute and the Kronos Science Laboratories will survey 570,000 letters of the genetic alphabet -- commonly known as "SNPs" -- in the DNA of 1,000 deceased persons confirmed to have Alzheimer's disease at autopsy and 1,000 deceased persons confirmed to be free of Alzheimer's disease at autopsy. "The technology to sift through the human blueprint at ultra-high resolution to get at the root of diseases such as Alzheimer's has finally come of age," explains Dietrich A. Stephan, the study's principal investigator.
GENES DETERMINE, RESTRICT STEM CELL FATE
Research on adult stem cells found in the skin hints at a new class of genes, according to a study by the University of Pennsylvania School of Medicine. These genes -- dubbed pangenes -- can both govern a stem cell's fate and put a hold on future differentiation until the time is right. Understanding the molecular control of these genes has implications for therapies that involve tissue regeneration. The researchers found that Pax3, a gene critical in embryonic development of melanocytes -- cells that make and store the pigments in the skin and hair -- also is expressed in adult stem cells in the skin. "Our findings told us that a recapitulation of an embryonic program is occurring in resident stem cells in adult skin," says Dr. Jon Epstein. Epstein and colleagues report their findings in Nature.
GENOME OF AMOEBA MORE COMPLEX THAN THOUGHT
The genome sequence of Entamoeba histolytica, a leading cause of diarrhea, includes a complex repertoire of sensory genes, a U.S. study finds. The report, in Nature, presents the first genome-wide study of an amoeba and the first genome sequence to be published from this class of amitochondrial human pathogens. The analysis reveals the degradation of the E. histolytica genome in its transition from a free-living organism into a parasite of the human gut. The study's author, Brendan Loftus, of the Institute for Genomic Research in Rockville, Md., says the contents of the amoeba's genome surprised many scientists. "The results give a fascinating glimpse of how this ancient parasite evolved and highlight unusual metabolic processes that may be exploitable as drug targets," says Matthew Berriman, of the Wellcome Trust Sanger Institute in the United Kingdom, who collaborated in the effort.
GENETIC TEST FOR INHERITED IMMUNE DEFICIENCY
A new U.S. genetic test could someday be added to the panel of tests that already screen newborns for a variety of disorders. Researchers at the National Human Genome Research Institute have developed a new test, which still must be validated before widespread use, to identify babies born with Severe Combined Immunodeficiency, or SCID. SCID is an illness in which the infant fails to develop a normal immune system. Babies can be infected by a wide range of viruses, bacteria and fungi that are normally controlled by a healthy baby's immune system. "This new laboratory technique is an excellent example of how increasingly sophisticated genetic tools can be applied to important public health problems," writes Dr. Eric D. Green, NHGRI scientific director, in the Journal of Allergy and Clinical Immunology.
CK2 PROTEIN SUSTAINS COLON CANCER CELL
A U.S. study shows success in blocking CK2 activity in tumor cells and an enhanced treatment might help patients with colorectal cancer. The protein CK2 plays a deadly role in colorectal carcinoma by blocking the ability of these tumors to activate a natural self-destruct mechanism that would clear this cancer from the body. The renegade CK2 protein keeps the tumor alive and growing by desensitizing the cancer cells to the effects of another protein called TRAIL. Normally, TRAIL triggers apoptosis -- cell suicide -- in the cancer cells as a way of protecting the body. For example, treating the tumors with TRAIL to trigger apoptosis, while blocking CK2, might enhance anti-cancer treatment for a variety of other solid tumors, according to Janet Houghton. The findings, by researchers at St. Jude Children's Research Hospital, are published in the online edition of Oncogene.
GENE TRANSFER FOR PERIPHERAL ARTERIAL DISEASE
Genzyme Corp., in Cambridge, Mass., says its first patient has been treated in a phase 2 clinical trial for patients with peripheral arterial disease. The experimental therapy -- using Ad2/HIF-1 alpha -- an engineered form of the HIF-1 alpha gene, is designed to promote the growth of new blood vessels and improve circulation in patients' limbs. The trial, a randomized double blind placebo controlled study, will take place at 35 medical centers in the United States and Europe, enrolling up to 300 patients diagnosed with severe intermittent claudication, a type of peripheral arterial disease that results in disabling pain or fatigue in the legs, brought on by exercise.
(EDITORS: For more information on COLON CANCER, Joanna Downer at (410) 614-5105 or firstname.lastname@example.org. For ALZHEIMER'S, Galen Perry at (602) 343-8423 or email@example.com. For STEM CELL, Ed Federico (215) 349-5659 or firstname.lastname@example.org. For AMOEBA, Robert Koenig at (301) 795-7880 or email@example.com. For TEST, Geoff Spencer at (301) 402-0911 or firstname.lastname@example.org. For CK2, Bonnie Cameron at (901) 495-4815 or email@example.com. For GENE TRANSFER, Dan Quinn at (617) 768-6849.)
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