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Showing posts with label Target. Show all posts
Showing posts with label Target. Show all posts

Sunday, July 7, 2013

Research Report Breakthrough In The Regulation Of A Key Cancer Drug Target

Main Category: Cancer / Oncology
Also Included In: Biology / Biochemistry;??Genetics
Article Date: 03 Jul 2013 - 1:00 PDT Current ratings for:
Research Report Breakthrough In The Regulation Of A Key Cancer Drug Target
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There's not much difference between what makes a man and what makes his beer - at least at the molecular level - according to a new study led by Professor John Schwabe at the University of Leicester.

Scientists used a powerful technique called protein crystallography to look at 3D structures of protein complexes purified from cultured human cells. They discovered that a family of complexes, that switch off gene expression, is regulated by small signalling molecules called inositol phosphates.

This latest study shows that this mode of regulation is conserved from yeast right through to man and is a fundamental process for life.

This discovery is potentially important for developing anti-cancer drugs since these complexes are emerging as effective cancer treatment targets.

The research was funded by the Wellcome Trust and involved collaboration with scientists from the University of Oxford. It was published online ahead of print (July 11) in the journal Molecular Cell.

The importance of this work is emphasised by the award, in November 2012, of £2.4 million in the form of a prestigious "Wellcome Trust Senior Investigator Award" to Professor John Schwabe to continue and develop this area of research.

Professor Schwabe said: "Gene regulation is an essential biological process that occurs in every cell in the body to control which proteins are expressed in particular tissues. We have been studying enzymes called Histone Deacetylases (HDACs) that regulate this process. The action of HDACs causes the DNA to become more tightly packaged and thus switches off genes by making them unavailable for expression. HDACs are recruited to DNA by a number of accessory proteins (corepressors) that target the enzyme to the correct gene."

In 2012, the research team announced in Nature that they had discovered a completely new and unexpected mechanism through which one particular HDAC complex (HDAC3 bound to its companion protein SMRT) is regulated.

Professor Schwabe said: "We wanted to ask whether this mode of regulation might apply to other HDAC complexes and be a general principle for HDAC regulation. Now we have taken this investigation several steps forward.

"We have solved the first structure of HDAC1 bound to one of its corepressor proteins (MTA1 - Metastasis-associated protein 1). This new structure allows us to examine how the proteins interact at the atomic level and reveals molecular details that have allowed us to probe the interaction surface.

"We have identified that there is an inositol phosphate-binding site at the interface between the two proteins, and through functional studies, we have confirmed that inositol phosphates are key regulators throughout this class of enzyme.

"This establishes that inositol phosphate regulation is a general paradigm that is conserved from yeast to man. In addition, we have shown that two MTA1 molecules come together to recruit two HDAC enzymes, and we suggest that MTA1 is critical for recruiting HDAC1 to DNA."

Professor Schwabe also emphasised that his research team is very privileged to have secured further funding from the Wellcome Trust to support this programme of research for the next 7 years: "We expect to gain an in depth insight into the role of inositol phosphates in the regulation of class I histone deacetylases and the specificity conferred to histone deacetylases by their recruitment into large multi protein complexes".

The research team used a cutting edge technique (protein crystallography) to look at the 3D structure of proteins involved in gene regulation. They optimised the conditions needed to grow microcrystals and took these to the UK's powerful synchrotron (Diamond Light Source, Oxford) to obtain diffraction data. These data are used to build images of the proteins, and for the first time, the team has been able analyse how the proteins interact with each other.

"With this new level of molecular detail we are exploring the design of novel HDAC inhibitors to target of the HDAC-corepressor interface. These may provide the foundation for future drug development and may lead to new anti-cancer therapies".

Article adapted by Medical News Today from original press release. Click 'references' tab above for source.
Visit our cancer / oncology section for the latest news on this subject. The University of Leicester team consisted of: Dr. Chris Millard, Dr. Peter Watson, Dr. Louise Fairall and Professor John Schwabe at the Biochemistry Department. The research involved a collaboration with Professor Dame Carol Robinson and Dr. Yuliya Gordiyenko at the Chemistry Department, University of Oxford.

University of Leicester

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5 Jul. 2013. APA

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'Research Report Breakthrough In The Regulation Of A Key Cancer Drug Target'

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Friday, June 28, 2013

'Undruggable' To Druggable: A New Target For Cancer Drug Development

Main Category: Stem Cell Research
Also Included In: Cancer / Oncology;??Lymphoma / Leukemia / Myeloma;??Genetics
Article Date: 19 Jun 2013 - 1:00 PDT Current ratings for:
'Undruggable' To Druggable: A New Target For Cancer Drug Development
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Harvard Stem Cell Institute (HSCI) researchers have identified in the most aggressive forms of cancer a gene known to regulate embryonic stem cell self-renewal, beginning a creative search for a drug that can block its activity.

The gene, SALL4, gives stem cells their ability to continue dividing as stem cells rather than becoming mature cells. Typically, cells only express SALL4 during embryonic development, but the gene is re-expressed in nearly all cases of acute myeloid leukemia and 10 to 30 percent of liver, lung, gastric, ovarian, endometrial, and breast cancers, strongly suggesting it plays a role in tumor formation.

In work published in the New England Journal of Medicine, two HSCI-affiliated labs - one in Singapore and the other in Boston - show that knocking out the SALL4 gene in mouse liver tumors, or interfering with the activity of its protein product with a small inhibitor, treats the cancer.

"Our paper is about liver cancer, but it is likely true about lung cancer, breast cancer, ovarian cancer, many, many cancers," said HSCI Blood Diseases Program leader Daniel Tenen, who also heads a laboratory at the Cancer Science Institute of Singapore (CSI Singapore). "SALL4 is a marker, so if we had a small molecule drug blocking SALL4 function, we could also predict which patients would be responsive."

Studying the therapeutic potential of a transcription factor is unusual in the field of cancer research. Transcription factors are typically avoided because of the difficulty of developing drugs that safely interfere with genetic targets. Most cancer researchers focus their attention on kinases.

The HSCI researchers' inquiry into the basic biology of the SALL4 gene, however, revealed another way to interfere with its activity in cancer cells. The gene's protein product is responsible for turning off a tumor-suppressor gene, causing the cell to divide uncontrollably. Using this knowledge, the researchers demonstrated that targeting the SALL4 protein with druglike molecules could halt tumor growth. "The pharmaceutical companies decided that if it is not a kinase and it is not a cell surface molecule, then it is 'undruggable,' " Tenen said. "To me, if you say anything is 'undoable,' you are limiting yourself as a biomedical scientist."

Earlier this year, Tenen's co-author, HSCI-affiliated faculty member Li Chai, a Harvard Medical School assistant professor of pathology at Brigham and Women's Hospital, published a paper in the journal Blood, reporting that a SALL4 inhibitor has similar treatment potential in leukemia cells.

Chai took blood samples from patients with acute myeloid leukemia, treated the leukemic cells with the inhibitor that interferes with SALL4 protein activity, and then transplanted the blood into mice. The result was a gradual regression of the same cancer in mice.

"I am excited about being on the front line of this new drug development," Chai said. "As a physician-scientist, if I can find a new class of drug that has very low toxicity to normal tissues, my patients can have a better quality of life."

Chai and Tenen are now working with HSCI Executive Committee member Lee Rubin, the Harvard Institute of Chemistry and Cell Biology, and James Bradner of Dana-Farber Cancer Institute, another HSCI-affiliated faculty member, to overcome the technical challenges of drug development and demonstrate the potential of SALL4 interference to treat other forms of cancer.

"I think as academics, we seek to engage drug companies because they can do these types of things better than we can," Tenen said. "But, also as an academic, I want to go after the important biologic targets that are not being sought after by the typical drug company - because if we do not, who will?"

Article adapted by Medical News Today from original press release. Click 'references' tab above for source.
Visit our stem cell research section for the latest news on this subject. The basic research that explored the biology of SALL4 was financed by a 2007 seed grant from HSCI, with more recent funding provided by a Singapore Translational Research Award from the Singapore National Medical Research Council, and grants from the Singapore Ministry of Education and National Research Foundation, and the National Institutes of Health. Kol Jia Yong, Chong Gao, and Henry Yang, among others, contributed to this work.
Harvard University Please use one of the following formats to cite this article in your essay, paper or report:

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University, Harvard. "'Undruggable' To Druggable: A New Target For Cancer Drug Development." Medical News Today. MediLexicon, Intl., 19 Jun. 2013. Web.
24 Jun. 2013. APA

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''Undruggable' To Druggable: A New Target For Cancer Drug Development'

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Sunday, June 2, 2013

Potential Therapeutic Target Discovered For Cushing's Disease

Main Category: Cancer / Oncology
Also Included In: Neurology / Neuroscience;??Endocrinology
Article Date: 10 May 2013 - 0:00 PDT Current ratings for:
Potential Therapeutic Target Discovered For Cushing's Disease
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Scientists at the Salk Institute for Biological Studies have identified a protein that drives the formation of pituitary tumors in Cushing's disease, a development that may give clinicians a therapeutic target to treat this potentially life-threatening disorder.

The protein, called TR4 (testicular orphan nuclear receptor 4), is one of the human body's 48 nuclear receptors, a class of proteins found in cells that are responsible for sensing hormones and, in response, regulating the expression of specific genes. Using a genome scan, the Salk team discovered that TR4 regulates a gene that produces adrenocorticotropic hormone (ACTH), which is overproduced by pituitary tumors in Cushing's disease (CD). The findings were published in the early online edition of Proceedings of the National Academy of Sciences.

"We were surprised by the scan, as TR4 and ACTH were not known to be functionally linked," says senior author Ronald M. Evans, a professor in Salk's Gene Expression Laboratory and a lead researcher in the Institute's Helmsley Center for Genomic Medicine. "TR4 is driving the growth and overexpression of ACTH. Targeting this pathway could therapeutically benefit treatment of CD."

In their study, Evans and his colleagues discovered that forced overexpression of TR4 in both human and mouse cells increased production of ACTH, cellular proliferation and tumor invasion rates. All of these events were reversed when TR4 expression was reduced.

First described more than 80 years ago, Cushing's disease is a rare disorder that is caused by pituitary tumors or excess growth of the pituitary gland located at the base of the brain. People with CD have too much ACTH, which stimulates the production and release of cortisol, a hormone that is normally produced during stressful situations.

While these pituitary tumors are almost always benign, they result in excess ACTH and cortisol secretion, which can result in various disabling symptoms, including diabetes, hypertension, osteoporosis, obesity and psychological disturbances. Surgical removal of the tumors is the first-line therapy, with remission rates of approximately 80 percent; however, the disease recurs in up to 25 percent of cases.

Drugs such as cabergoline, which is used to treat certain pituitary tumors, alone or in combination with ketoconazole, a drug normally used to treat fungal infections, have been shown to be effective in some patients with Cushing's disease. More recently, mefipristone-best known as the abortion pill RU-486-was approved by the FDA to treat CD. Despite these advances in medical therapy, the Salk scientists say additional therapeutic approaches are needed for CD.

"Pituitary tumors are extremely difficult to control," says Michael Downes, a senior staff scientist in the Gene Expression Laboratory and a co-author of the study. "To control them, you have to kill cells in the pituitary gland that are proliferating, which could prevent the production of a vital hormone."

Previous studies have found that, by itself, TR4 is a natural target for other signaling molecules in the pituitary. Small-molecule inhibitors that have been developed for other cancers could be potentially applied to disrupt this signaling cascade. "Our discovery," says Evans, a Howard Hughes Medical Institute investigator and holder of the March of Dimes Chair in Molecular and Developmental Biology, "might lead clinicians to an existing drug that could be used to treat Cushing's disease."

Article adapted by Medical News Today from original press release. Click 'references' tab above for source.
Visit our cancer / oncology section for the latest news on this subject. Other researchers on the study were Li Du, Marvin Bergsneider, Leili Mirsadraei, Stephen H. Young, William H. Yong and Anthony P. Heaney of the David A. Geffen School of Medicine at the University of California, Los Angeles, and Johan W. Jonker of the University of Groningen.
The study was supported by the National Institutes of Health, the Leona M. and Harry B. Helmsley Charitable Trust, the Samuel Waxman Cancer Research Foundation, the Jonsson Comprehensive Cancer Center at UCLA, and Ipsen/Biomeasure.
Salk Institute Please use one of the following formats to cite this article in your essay, paper or report:

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Institute, Salk. "Potential Therapeutic Target Discovered For Cushing's Disease." Medical News Today. MediLexicon, Intl., 10 May. 2013. Web.
13 May. 2013. APA

Please note: If no author information is provided, the source is cited instead.


'Potential Therapeutic Target Discovered For Cushing's Disease'

Please note that we publish your name, but we do not publish your email address. It is only used to let you know when your message is published. We do not use it for any other purpose. Please see our privacy policy for more information.

If you write about specific medications or operations, please do not name health care professionals by name.

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For any corrections of factual information, or to contact the editors please use our feedback form.

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Note: Any medical information published on this website is not intended as a substitute for informed medical advice and you should not take any action before consulting with a health care professional. For more information, please read our terms and conditions.



View the original article here