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chanon chiarnpattanodom

Cancer epigenetics takes center stage - 1 views

www.pnas.org/...392.full

shared by chanon chiarnpattanodom on 16 Apr 12 - No Cached
    • chanon chiarnpattanodom
      chanon chiarnpattanodom on 16 Apr 12
       
      DNA methylation is a chemical process where a methyl group is added on either the cytosine ring or the adenine ring, used in "higher leveled" organisms. Important in cell differentiation since methylation will cause cells to "remember" and remain differenciated instead of expressing other genes. 
  • Epigenetics is defined as modifications of the genome, heritable during cell division, that do not involve a change in the DNA sequence.
  • Epigenetic alterations in cancer include global hypomethylation
  • ...18 more annotations...
  • the promoters of housekeeping genes that are generally protected from methylation.
  • may lead to aberrant silencing of tumor suppressor genes
  • discovered loss of imprinting (LOI) in cancer
  • Genomic imprinting, the subject of the report by Nakagawa et al. (2), is an epigenetic modification of a specific parental allele of a gene, or the chromosome on which it resides, in the gamete or zygote, leading to differential expression of the two alleles of the gene in somatic cells of the offspring.
  • we found that LOI can occur in the normal colonic mucosa of colorectal cancer patients with LOI in their tumors
  • This LOI was linked to cases showing microsatellite instability (MSI) in the tumors
  • However, these patients do not have mutations in mismatch repair genes
  • One potential cause of MSI in these sporadic cancers is hypermethylation and epigenetic silencing of the hMLH1 mismatch repair gene
  • Nakagawa et al. (2) now confirm the original study of Cui et al. that LOI occurs in both tumor and normal tissue of patients
  • The present study (2) also offers an intriguing mechanistic hypothesis to explain the relationship between H19 DMR methylation and LOI in these patients
  • Nevertheless, the study calls attention to this remarkable highly conserved multifunctional protein,
  • The potential link to CTCF suggested by this study also calls our attention to the link among DNA methylation, epigenetics, and chromatin.
  • A clue to the link between MSI and epigenetics may be provided by another sometimes overlooked common thread in epigenetics, namely DNA replication
  • repeat-induced gene silencing is thought to be propagated through hemimethylated intermediates during DNA replication
  • The studies of Cui et al. (11), Nishihara et al. (20), and Nakagawa et al. (2) suggest a new and provocative view of the timing of epigenetic changes in cancer.
  • Studies of transgenic mice with constitutive biallelic expression of IGF2, comparable to LOI, show reduced apoptosis and increased tumor formation
  • I conclude by noting that the distinction between cancer genetics and epigenetics has blurred considerably in recent years
  • Many conventional “genetic” mechanisms directly affect proteins that regulate chromatin,
nidthamsirisup

Epigenetics: DNA Isn't Everything - 0 views

www.sciencedaily.com/...090412081315.htm

epigenetics genetics gene

shared by nidthamsirisup on 15 Apr 12 - Cached
  • Research into epigenetics has shown that environmental factors affect characteristics of organisms. These changes are sometimes passed on to the offspring.
  • A certain laboratory strain of the fruit fly Drosophila melanogaster has white eyes. If the surrounding temperature of the embryos, which are normally nurtured at 25 degrees Celsius, is briefly raised to 37 degrees Celsius, the flies later hatch with red eyes.
  • crossed the flies for six generations. In this experiment, they were able to prove that the temperature treatment changes the eye colour of this specific strain of fly, and that the treated individual flies pass on the change to their offspring over several generations. However, the DNA sequence for the gene responsible for eye colour was proven to remain the same for white-eyed parents and red-eyed offspring.
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  • Epigenetics examines the inheritance of characteristics that are not set out in the DNA sequence.
  • important factors are the histones, a kind of packaging material for the DNA, in order to store DNA in an ordered and space-saving way. It is now clear that these proteins have additional roles to play. Depending on the chemical group they carry, if they are acetylated or methylated, they permanently activate or deactivate genes.
  • New methods now allow researchers to sometimes directly show which genes have been activated or deactivated by the histones
  • The genetic information of the DNA is passed on along with the relevant epigenetic information for the respective cell type.
  • A similar question remains for the inheritance of the epigenetic characteristics from parents to offspring. They now know that when the gametes are formed, certain epigenetic markers remain and are passed on to the offspring. The questions, which are currently being researched, are how much and which part of the epigenetic information is preserved and subsequently inherited.
  • Diet and epigenetics appear to be closely linked. The most well known example is that of the Agouti mice: they are yellow, fat and are prone to diabetes and cancer. If Agouti females are fed with a cocktail of vitamin B12, folic acid and cholin, directly prior to and during pregnancy, they give birth to mainly brown, slim and healthy offspring. They in turn mainly have offspring similar to themselves.
  • Environmental factors, which change the characteristics of an individual and are then passed on to its offspring, do not really fit into Darwin’s theory of evolution. According to his theory, evolution is the result of the population and not the single individual. “Passing on the gained characteristics fits more to Lamarck’s theory of evolution”, says Paro.
nidthamsirisup

Epigenetics Seeks Clues to Mental Illness in Genes' Life Story - Science in 2011 - NYTi... - 0 views

www.nytimes.com/...09brain.html

epigenetics DNA Genes disease

shared by nidthamsirisup on 15 Apr 12 - No Cached
  • epigenetics, the study of how people’s experience and environment affect the function of their genes.
  • Studies suggest that such add-on, or epigenetic, markers develop as an animal adapts to its environment, whether in the womb or out in the world — and the markers can profoundly affect behavior.
  • In studies of rats, researchers have shown that affectionate mothering alters the expression of genes, allowing them to dampen their physiological response to stress. These biological buffers are then passed on to the next generation: rodents and nonhuman primates biologically primed to handle stress tend to be more nurturing to their own offspring, and the system is thought to work similarly in humans.
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  • the offspring of parents who experience famine are at heightened risk for developing schizophrenia, some research suggests — perhaps because of the chemical signatures on the genes that parents pass on.
  • in some people with autism, epigenetic markers had silenced the gene which makes the receptor for the hormone oxytocin. Oxytocin oils the brain’s social circuits, and is critical in cementing relationships; a brain short on receptors for it would most likely struggle in social situations.
  • In one large study of people with schizophrenia, researchers at Johns Hopkins are analyzing blood and other data to see whether the degree of epigenetic variation is related to the inherited risk of developing the disorder. In another, researchers at Tufts are studying the genes of animals dependent on opiates to see how epigenetic alterations caused by drug exposure affect the opiate sensitivity of the animals’ offspring.
adisa narula

Breaking the Silence: The Rise of Epigenetic Therapy - 0 views

jnci.oxfordjournals.org/...874.full

cancer DNA genetics research epigenetic

shared by adisa narula on 12 Apr 12 - No Cached
  • adisa narula on 12 Apr 12
     
    Cancer epigenetics is hot. At the annual meeting of the American Association for Cancer Research in April, once-obscure principal investigators were feted by gaggles of admirers and many poster presenters mobbed by the curious. "It's one of the hottest areas of basic biology," said Paul Workman, Ph.D., director of cancer therapeutics at Cancer Research U.K.
Sea Maskulrath

Changes in gene expression causes high BP in pregnancy - 1 views

zeenews.india.com/...igh-bp-in-pregnancy_16515.html

epigenetics DNA human

shared by Sea Maskulrath on 16 Apr 12 - No Cached
  • Washington: Researchers have discovered that changes in the gene expression of a key enzyme may contribute to high blood pressure and increase susceptibility to forming blood clots in pregnant women with preeclampsia.
  • Epigenetics refers to changes in gene expression that are mediated through mechanisms other than changes in the DNA sequence.
  • The VCU team reported that thromboxane synthase – an important inflammatory enzyme – is increased in the blood vessels of expectant mothers with preeclampsia.The thromboxane synthase gene codes for this enzyme, which is involved in several processes including cardiovascular disease and stroke. This enzyme results in the synthesis of thromboxane, which increases blood pressure and causes blood clots.
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  • According to Walsh, one of the main epigenetic mechanisms is methylation of the DNA, which controls the expression of genes. The increase of
  • his enzyme in the blood vessels is related to reduced DNA methylation and the infiltration of neu
  • enzyme
  • trophils
  • trophils into the blood vessels. Neutrophils are white blood cells that normally help fight infection.
Paige Prescott

Old Cancer Drugs Offer New Tricks - Science News - 0 views

www.sciencenews.org/..._cancer_drugs_offer_new_tricks

cancer epigenetics

shared by Paige Prescott on 14 Apr 12 - No Cached
  • Drugs that alter some chemical tags on DNA make cancer cells behave more like normal cells
  • And the drugs seem to make cancer cells more susceptible to chemotherapy and attacks from the immune system.
  • drugs called azacitidine and decitabine, when used in low doses, change gene activity in leukemia and breast cancer cells in the lab. If DNA is a cell’s hard drive, then chemical tags attached to the DNA or DNA-packaging proteins called histones serve as software packages to tell the hard drive how to function. This type of chemical programming is called epigenetics.
Pop karnchanapimonkul

Dieting During Pregnancy Increases Risk Of Obesity And Diabetes For Offspring - 0 views

www.medicalnewstoday.com/...243627.php

dieting obesity diabetes epigenics offspring

shared by Pop karnchanapimonkul on 14 Apr 12 - No Cached
  • babies of mothers who diet around the time of conception and in early pregnancy, may have an increased risk of obesity and type 2 diabetes throughout their lives. This study provides exciting insights into how behavior can lead to epigenetic changes in offspring related to obesity and disease.
  • dieting around the time a baby is conceived may increase the chance of the child becoming obese later in life
  • changes in the genes that control food intake and glucose levels that may lead to obesity and diabetes.
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  • epigenetic changes with alterations in the structure of the DNA and its associated proteins, histones, which affects the way that genes can behave in later life.
  • Pop karnchanapimonkul on 14 Apr 12
     
    Article about how dieting during pregnancy cause offsprings to have a change in genes.
Kaoko Miyazaki

Long Intergenic Noncoding RNAs: New Links in Cancer Progression - 1 views

cancerres.aacrjournals.org/...3.full

research gene epigenetics RNA

shared by Kaoko Miyazaki on 16 Apr 12 - No Cached
  • Kaoko Miyazaki on 16 Apr 12
     
    The newly discovered and currently being researched lincRNAs are seen to be one of the causes of cancer. The function of lincRNAs to control gene expression by regulating the number of histones according to specific chromatin, may cause cancer when done wrong or are altered in some way. The epigenetic alterations that occur when this function is done wrong may lead to the disease and the inheritance of it. Which could be hypothesized as to why people with a history of cancer (and other diseases) within their families have higher likelihood to being diagnosed with the disease. But because lincRNA is a very recent discovery and only less than 1% of it has has been characterized in the human body, evidence of this is still being researched, tested and studied.
adisa narula

The Top 10 Everything of 2009 - TIME - 1 views

www.time.com/...945379_1944416_1944420,00.html

dna genetics disease epigenetic

shared by adisa narula on 01 Apr 12 - No Cached
  • adisa narula on 01 Apr 12
     
    The decoding of the human genome nearly a decade ago fueled expectations that an understanding of all human hereditary influences was within sight. But the connections between genes and, say, disease turned out to be far more complicated than imagined.
orasa sukmark

Shot of Young Stem Cells Makes Rapidly Aging Mice Live Much Longer and Healthier - Gate... - 1 views

www.gate2biotech.com/-2130

shot stem cells aging much mice longer gate biotech com DNA genetics disease gene RNA brain human epigenetics research Genes

shared by orasa sukmark on 16 Apr 12 - No Cached
  • animals that got the stem/progenitor cells improved their health and lived two to three times longer than expected,
  • "Our experiments showed that mice that have progeria, a disorder of premature aging, were healthier and lived longer after an injection of stem cells from young, healthy animals," Dr. Niedernhofer said. "That tells us that stem cell dysfunction is a cause of the changes we see with aging."
  • "Typically the progeria mice die at around 21 to 28 days of age, but the treated animals lived far longer -- some even lived beyond 66 days. They also were in better general health."
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  • we injected stem/progenitor cells from young, healthy mice into the abdomens of 17-day-old progeria mice,
  • As the progeria mice age, they lose muscle mass in their hind limbs, hunch over, tremble, and move slowly and awkwardly. Affected mice that got a shot of stem cells just before showing the first signs of aging were more like normal mice, and they grew almost as large.
  • orasa sukmark on 16 Apr 12
     
    the experiment from the University of Pittsburgh shows that the mice can be stronger live longer after they were injected with stem cells from young healthy animals.
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