Scientists at Cold Spring Harbor Laboratory (CSHL) today report a discovery that they hope will lead to the development of a powerful new way of treating an aggressive form of breast cancer.
The breast cancer subtype in question is commonly called "HER2-positive"; it's a subset of the disease affecting about one patient in four, in which tumor cells overexpress a signaling protein called HER2.
The blockbuster drug Herceptin is a treatment of choice for many women with HER2-positive breast cancer, but in most cases, resistance to the treatment develops within several years. The prognosis for HER2-positive breast cancer patients is worse than for those with other subtypes of the illness.
In a paper appearing online today in Nature Chemical Biology, a multi-institution team led by CSHL Professor Nicholas Tonks reports that it has found a means of inhibiting another protein, called PTP1B, whose expression is also upregulated in HER2-positive breast cancer. PTP1B has been shown to play a critical role in the development of tumors in which HER2 signaling is aberrant.
When they treated mice modeling HER2-positive breast cancer with a PTP1B inhibitor called MSI-1436 (also called trodusquemine), Tonks and colleagues inhibited signaling by HER2 proteins.
"The result was an extensive inhibition of tumor growth and prevention of metastasis to the lung in HER2-positive animal models of breast cancer," notes Navasona Krishnan, Ph.D., a postdoctoral investigator in the Tonks lab who performed many of the experiments and is lead author on the paper reporting the results.
Dr. Tonks discovered PTP1B some 25 years ago. It is an enzyme – one in a "superfamily" of 105 called protein tyrosine phosphatases (PTPs) -- that perform the essential biochemical task of removing phosphate groups from amino acids called tyrosines in other proteins. Adding and removing phosphate groups is one of the means by which signals are sent among proteins.
PTP1B for many years has been a target of interest among drug developers. It is well known to be a negative regulator of insulin – an antagonist of insulin signaling -- and of signaling by leptin, the hormone that helps regulate appetite. Drugs that can block or inhibit the action of PTP1B have great potential in controlling diabetes and obesity. Yet properties of the molecule -- involving both its charged active binding site and its shape – have stymied potential developers of inhibitory drugs.
The new paper by Tonks and collaborators importantly reveals an alternative binding site, called an allosteric site, that does not present the biochemical difficulties that the active, or "catalytic," binding site does. This allosteric site is a target of the candidate drug trodusquemine.
Later this year early-stage human trials will begin for the drug, a collaboration of CSHL and North Shore-Long Island Jewish Hospital. Dr. Tonks and CSHL have interests in a joint venture called DepYmed Inc., in partnership with Ohr Pharmaceutical (NasdaqCM: OHRP). The venture seeks to develop trodusquemine and related analogs.
Funders for the research discussed in this release include: the National Institutes of Health, Cold Spring Harbor Laboratory Cancer Center, American Diabetes Association, Brown University Research Seed Fund, and Agence Nationale de Researche.
"Targeting the disordered C terminus of PTP1B with an allosteric inhibitor" appears online ahead of print Sunday, May 18, 2014 in Nature Chemical Biology. The authors are: Navasona Krishnan, Dorothy Koveal, Daniel H. Miller, Bin Xue, Sai Dipikaa Akshinthala, Jaka Kragelj, Malene Ringkjobing Jensen, Carla-Maria Gauss, Rebecca Page, Martin Blackledge, Senthil K. Musthuswamy, Wolfgang Peti and Nicholas K. Tonks. the paper can be obtained at: http://www.nature.com/nchembio/journal/vaop/ncurrent/index.html
About Cold Spring Harbor Laboratory
Founded in 1890, Cold Spring Harbor Laboratory (CSHL) has shaped contemporary biomedical research and education with programs in cancer, neuroscience, plant biology and quantitative biology. CSHL is ranked number one in the world by Thomson Reuters for the impact of its research in molecular biology and genetics. The Laboratory has been home to eight Nobel Prize winners. Today, CSHL's multidisciplinary scientific community is more than 600 researchers and technicians strong and its Meetings & Courses program hosts more than 12,000 scientists from around the world each year to its Long Island campus and its China center. For more information, visit http://www.cshl.edu.
Peter Tarr | Eurek Alert!
Biofilm discovery suggests new way to prevent dangerous infections
23.05.2017 | University of Texas at Austin
Another reason to exercise: Burning bone fat -- a key to better bone health
19.05.2017 | University of North Carolina Health Care
Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.
The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....
An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.
We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...
Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.
Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...
An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...
In the race to produce a quantum computer, a number of projects are seeking a way to create quantum bits -- or qubits -- that are stable, meaning they are not much affected by changes in their environment. This normally needs highly nonlinear non-dissipative elements capable of functioning at very low temperatures.
In pursuit of this goal, researchers at EPFL's Laboratory of Photonics and Quantum Measurements LPQM (STI/SB), have investigated a nonlinear graphene-based...
24.05.2017 | Event News
23.05.2017 | Event News
22.05.2017 | Event News
24.05.2017 | Physics and Astronomy
24.05.2017 | Physics and Astronomy
24.05.2017 | Event News