 |
|
New telomere discovery could help explain why cancer cells never stop dividing
October 05, 2007A group working at the Swiss Institute for Experimental Cancer Research (ISREC) in collaboration with the University of Pavia has discovered that telomeres, the repeated DNA-protein complexes at the end of chromosomes that progressively shorten every time a cell divides, also contain RNA. This discovery, published online October 4 in Science Express, calls into question our understanding of how telomeres function, and may provide a new avenue of attack for stopping telomere renewal in cancer cells.
Inside the cell nucleus, all our genetic information is located on twisted, double stranded molecules of DNA which are packaged into chromosomes. At the end of these chromosomes are telomeres, zones of repeated chains of DNA that are often compared to the plastic tips on shoelaces because they prevent chromosomes from fraying, and thus genetic information from getting scrambled when cells divide. The telomere is like a cellular clock, because every time a cell divides, the telomere shortens. After a cell has grown and divided a few dozen times, the telomeres turn on an alarm system that prevents further division. If this clock doesn't function right, cells either end up with damaged chromosomes or they become "immortal" and continue dividing endlessly - either way it's bad news and leads to cancer or disease. Understanding how telomeres function, and how this function can potentially be manipulated, is thus extremely important.
The DNA in the chromosome acts like a sort of instruction manual for the cell. Genetic information is transcribed into segments of RNA that then go out into the cell and carry out a variety of tasks such as making proteins, catalyzing chemical reactions, or fulfilling structural roles. It was thought that telomeres were "silent" - that their DNA was not transcribed into strands of RNA. The researchers have turned this theory on its head by discovering telomeric RNA and showing that this RNA is transcribed from DNA on the telomere.
Why is this important" In embryonic cells (and some stem cells), an enzyme called telomerase rebuilds the telomere so that the cells can keep dividing. Over time, this telomerase dwindles and eventually the telomere shortens and the cell becomes inactive. In cancer cells, the telomerase enzyme keeps rebuilding telomeres long past the cell's normal lifetime. The cells become "immortal", endlessly dividing, resulting in a tumor. Researchers estimate that telomere maintenance activity occurs in about 90% of human cancers. But the mechanism by which this maintenance takes place is not well understood. The researchers discovered that the RNA in the telomere is regulated by a protein in the telomerase enzyme. Their discovery may thus uncover key elements of telomere function.
"It's too early to give yet a definitive answer," to whether this could lead to new cancer therapies, notes Joachim Lingner, senior author on the paper. "But the experiments published in the paper suggest that telomeric RNA may provide a new target to attack telomere function in cancer cells to stop their growth."
Ecole Polytechnique Fédérale de Lausanne
Why is this important" In embryonic cells (and some stem cells), an enzyme called telomerase rebuilds the telomere so that the cells can keep dividing. Over time, this telomerase dwindles and eventually the telomere shortens and the cell becomes inactive. In cancer cells, the telomerase enzyme keeps rebuilding telomeres long past the cell's normal lifetime. The cells become "immortal", endlessly dividing, resulting in a tumor. Researchers estimate that telomere maintenance activity occurs in about 90% of human cancers. But the mechanism by which this maintenance takes place is not well understood. The researchers discovered that the RNA in the telomere is regulated by a protein in the telomerase enzyme. Their discovery may thus uncover key elements of telomere function.
"It's too early to give yet a definitive answer," to whether this could lead to new cancer therapies, notes Joachim Lingner, senior author on the paper. "But the experiments published in the paper suggest that telomeric RNA may provide a new target to attack telomere function in cancer cells to stop their growth."
Ecole Polytechnique Fédérale de Lausanne
Telomere Current Events and Telomere News RSSPossible Link Studied Between Childhood Abuse and Early Cellular Aging
Children who suffer physical or emotional abuse may be faced with accelerated cellular aging as adults, according to new research from Butler Hospital and Brown University.
Common weed could provide clues on aging and cancer
A common weed and human cancer cells could provide some very uncommon details about DNA structure and its relationship with telomeres and how they affect cellular aging and cancer, according to a team led by scientists from Texas A&M University and the University of Cincinnati (UC).
Mice regain ability to extend telomeres suggesting potential for dyskeratosis congenita therapy
The human genetic disease dyskeratosis congenita (DKC) is an autosomal dominant disease that leads to abnormalities in tissues with a rapid cell turnover - the skin, nails, bone marrow, lungs and gut.
National Science Foundation congratulates Nobel Laureates in medicine/physiology, chemistry and economics
The National Science Foundation (NSF) congratulates the 2009 Nobel laureates, particularly those who have received NSF funding over the years: Jack W. Szostak, who shared the prize in physiology or medicine; Thomas A. Steitz, who shared the prize in chemistry; and Elinor Ostrom and Oliver E. Williamson who earned the Sveriges Riksbank Prize in economic sciences in memory of Alfred Nobel 2009.
Researchers identify protein-telomere interactions that could be key in treating cancer
A team of researchers from The Wistar Institute have shown that a large non-coding RNA in mammals and yeast plays a central role in helping maintain telomeres, the tips of chromosomes that contain important genetic information and help regulate cell division.
Protein plays unexpected role protecting chromosome tips
A protein specialist that opens the genomic door for DNA repair and gene expression also turns out to be a multi-tasking workhorse that protects the tips of chromosomes and dabbles in a protein-destruction complex, a team lead by researchers at The University of Texas M. D. Anderson Cancer Center reports in the Aug. 13 edition of Molecular Cell.
First sister study results reinforce the importance of healthy living
Women who maintain a healthy weight and who have lower perceived stress may be less likely to have chromosome changes associated with aging than obese and stressed women, according to a pilot study that was part of the Sister Study.
Enhanced skin cancer risk linked to defects in cellular aging controls
Cell lifespan is limited by telomeres, DNA sequences that cap chromosomes and control the number of times a cell may be copied. A new study reported in Disease Models & Mechanisms (DMM), dmm.biologists.org, describes how telomere dysfunction in skin cells can lead to increased skin cancer risk and pigmentation.
UT Southwestern researchers identify gene linked to inherited form of fatal lung disease
Researchers at UT Southwestern Medical Center have determined that a mutation in a gene known for its role in defending the lungs against invading pathogens is responsible for some inherited cases of a lethal lung disease affecting older adults. The same mutation may also be associated with lung cancer, the researchers said.
Researchers use chemical from medicinal plants to fight HIV
Like other kinds of cells, immune cells lose the ability to divide as they age because a part of their chromosomes known as a telomere becomes progressively shorter with cell division. As a result, the cell changes in many ways, and its disease fighting ability is compromised.
More Telomere Current Events and Telomere News Articles
 |
Elizabeth Blackburn and the Story of Telomeres: Deciphering the Ends of DNA by Catherine Brady (Author) Molecular biologist Elizabeth Blackburn—one of Time magazine’s 100 “Most Influential People in the World” in 2007—made headlines in 2004 when she was dismissed from the President's Council on Bioethics after objecting to the council's call for a moratorium on stem cell research and protesting the suppression of relevant scientific evidence in its final report. But it is Blackburn's groundbreaking work on telomeric DNA, which launched the field of telomere research, that will have the more profound and long-lasting effect on science and society. In this compelling biography, Catherine Brady tells the story of Elizabeth Blackburn's life and work and the emergence of a new field of scientific research on the specialized ends of chromosomes and the telomerase enzyme that extends... |
 |
Telomeres, Second Edition (Cold Spring Harbor Monograph Series) by Vicki Lundblad (Author), Elizabeth Blackburn (Author), Vicki Lundblad (Editor), Elizabeth Blackburn (Editor), Titia de Lange (Editor) An uptodate survey of the current exciting state of telomere biology. Telomeresspecialized structures found at the ends of chromosomes are essential for maintaining the integrity of chromosomes and their faithful duplication during cell division. Chapters in this volume cover telomere structure and function in a range of organisms, focusing on how they are maintained, their roles in cell division and gene expression, and how deficiencies in these structures contribute to cancers and other diseases and even aging. |
 |
The Stellar Sea Telomere (Primary Contributor) |
 |
Telomeres and Telomerase in Aging, Disease, and Cancer: Molecular Mechanisms of Adult Stem Cell Ageing by K. Lenhard Rudolph (Author), K. Lenhard Rudolph (Editor) The understanding of the molecular mechanisms underlying the ageing process is essential to improve quality of life and health span in the growing populations of the elderly. Telomere shortening represents one of the basic aspects of ageing and telomere dysfunction could contribute to the accumulation of DNA damage during ageing. This book summarizes experimental evidence and clinical data indicating that telomere dysfunction influences human ageing, diseases and cancer. In addition, the book describes our current knowledge on checkpoints that limit cellular lifespan (senescence) and survival (apoptosis, crisis) in response to telomere dysfunction. A special focus of the book is on adult stem cells. There is emerging evidence that adult stem cell ageing impairs... |
 |
The Stellar Sea by Telomere |
 |
Telomeres: Function, Shortening and Lengthening by Leonardo Mancini (Editor) Telomeres are a region of repetitive DNA at the end of chromosomes, which protects the end of the chromosome from destruction. They protect chromosome ends from degradation and thus prevent chromosome end fusion. This book describes the relevance of telomeres in the human ageing process and the telomere defects that play a role in the premature aging process. Dysfunctional telomeres that can promote chromosome instability, leading to DNA amplifications and terminal deletions, cell cycle arrest and cell death, are also described. The biology and function of both telomeres and telomerase are described in this book. The possible connection between telomeres, ageing and senescence, as well as the many disorders and chronic diseases where telomere biology seems to be important are addressed,... |
 |
Telomeres and Telomerase: Methods and Protocols (Methods in Molecular Biology) by John A. Double (Author), Michael J. Thompson (Author) John A. Double and Michael J. Thompson have collected a critically important series of novel and essential techniques for studying telomeres and telomerase. These readily reproducible methods provide cutting-edge tools to identify, measure, and analyze telomeres, to determine telomerase expression at the RNA level, to determine telomerase activity, and to detect potential modifiers of this activity. The techniques for assaying telomerase activity range from standard radiological TRAP assays to nonradioactive methods, from non PCR-based methods to techniques using real-time PCR. Telomeres and Telomerase: Methods and Protocols provides the core array of productive techniques needed today to develop telomerase inhibitors or diagnostic/prognostic telomerase markers. |
 |
Telomeres and Telomerase in Cancer (Cancer Drug Discovery and Development) by Keiko Hiyama (Editor) Telomerase, an enzyme that maintains telomeres and endows eukaryotic cells with immortality, was first discovered in tetrahymena in 1985. In 1990s, it was proven that this enzyme also plays a key role in the infinite proliferation of human cancer cells. Now telomere and telomerase are widely accepted as important factors involved in cancer biology, and as promising diagnostic tools and therapeutic targets. Recently, role of telomerase in “cancer stem cells” has become another attractive story. Until now, there are several good books on telomere and telomerase focusing on biology in ciliates, yeasts, and mouse or basic sciences in human, providing basic scientists or students with updated knowledge. |
 |
The Telomere by David Kipling (Author) Telomeres--specialized structures at ends of linear chromosomes--serve a fascinating range of functions that molecular biologists and geneticists are only beginning to understand and exploit. For example, telomeres distinguish the natural end of a chromosome from a simple double-strand break, stabilize chromosomes by protecting them from fusion or activating cell cycle checkpoints, and provide mechanisms to compensate for the loss of terminal DNA sequence that occurs when linear DNA molecules are replicated. This book--the first to cover this exciting and rapidly expanding field--integrates the increasingly disparate strands of telomere research to provide an invaluable survey of the subject. Topics include the role of telomeres in nuclear organization; telomere DNA sequence and unusual... |
|
Astral Currents by Telomere |
| © 2009 BrightSurf.com |