CU News
News from the University of Colorado in Boulder.
CU Boulder researchers uncover new target for cancer research
Oct 25th
Researchers in the two scientists’ laboratories collaborated to find a patch of amino acids that, if blocked by a drug docked onto the chromosome end at this location, may prevent cancerous cells from reproducing. The amino acids at this site are called the “TEL patch” and once modified, the end of the chromosome is unable to recruit the telomerase enzyme, which is necessary for growth of many cancerous cells.
“This is an exciting scientific discovery that gives us a new way of looking at the problem of cancer,” Cech said. “What is amazing is that changing a single amino acid in the TEL patch stops the growth of telomeres. We are a long way from a drug solution for cancer, but this discovery gives us a different, and hopefully more effective, target.”
Cech is the director of the BioFrontiers Institute, a Howard Hughes Medical Investigator and winner of the 1989 Nobel Prize in chemistry.
Co-authors on the study include postdoctoral fellows Jayakrishnan Nandakumar and Ina Weidenfeld; University of Colorado undergraduate student Caitlin Bell; and Howard Hughes Medical Institute Senior Scientist Arthur Zaug.
Telomeres have been studied since the 1970s for their role in cancer. They are constructed of repetitive nucleotide sequences that sit at the ends of our chromosomes like the ribbon tails on a bow. This extra material protects the ends of the chromosomes from deteriorating, or fusing with neighboring chromosome ends. Telomeres are consumed during cell division and, over time, will become shorter and provide less cover for the chromosomes they are protecting. An enzyme called telomerase replenishes telomeres throughout their lifecycles.
Telomerase is the enzyme that keeps cells young. From stem cells to germ cells, telomerase helps cells continue to live and multiply. Too little telomerase produces diseases of bone marrow, lungs and skin. Too much telomerase results in cells that over proliferate and may become “immortal.” As these immortal cells continue to divide and replenish, they build cancerous tumors. Scientists estimate that telomerase activation is a contributor in up to 90 percent of human cancers.
To date, development of cancer therapies has focused on limiting the enzymatic action of telomerase to slow the growth of cancerous cells. With their latest discovery, Cech and Leinwand envision a cancer drug that would lock into the TEL patch at chromosome ends to keep telomerase from binding there. This approach of inhibiting the docking of telomerase may be the elegant solution to the complex problem of cancerous cells. Cech, a biochemist, and Leinwand, a biologist, joined forces to work on their latest solution.
“This work was really made possible by the fact that our labs are so close,” Leinwand said. “My lab was able to provide the cell biology and understanding of genetics, and Tom’s lab allowed us to explore the biochemistry. We have a unique situation at BioFrontiers where labs and people comingle to make discoveries just like this.”
Leinwand is the chief scientific officer of the BioFrontiers Institute and a professor of molecular, cellular and developmental biology.
Researchers at the University of Colorado have a significant history in developing marketable biotechnologies. Cech founded Ribozyme Pharmaceuticals Inc. Leinwand co-founded Myogen with CU professor Michael Bristow, Hiberna and recently launched MyoKardia (http://www.myokardia.com/about.php).
The BioFrontiers Institute is an interdisciplinary institute housed at the Jennie Smoly Caruthers Biotechnology Building at CU-Boulder. The institute is dedicated to training the next generation of interdisciplinary scientists through its IQ Biology Interdisciplinary Quantitative Biology Ph.D. program. For more information about BioFrontiers visithttp://biofrontiers.colorado.edu
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CU Boulder study finds racial ‘hierarchy of bias’ drives decision to shoot armed, unarmed suspects
Oct 24th
Both the police and student subjects were most likely to shoot at blacks, then Hispanics, then whites and finally, in a case of what might be called a positive bias, Asians, researchers found.
In the first study of its kind, Joshua Correll, Bernadette Park and Charles M. Judd of CU-Boulder’s Department of Psychology and Neuroscience and Melody Sadler of San Diego State University examined how police and a group of undergraduate subjects decide whether to shoot or not to shoot “suspects” in a multi-ethnic environment.
“Most studies on the subject of stereotyping and prejudice look at two (ethnic) groups, usually in isolation. It’s always one group against another group,” said Correll, a CU graduate who joined the faculty in August after a stint at the University of Chicago.
“But as the country becomes more ethnically diverse, it’s more and more important to start thinking about how we process racial and ethnic cues in a multicultural environment,” he said.
As with previous studies into the question, data were gathered from subjects playing a “first person shooter” video game, in which figures of varying ethnicity — Caucasian, Asian, Hispanic and African-American — pop up, either “armed” with a weapon or another benign object, such as a cell phone.
Participants — 69 CU-Boulder undergraduates and 254 police officers — had to make quick decisions as to which figures posed a “threat” and shoot them. The police officers were recruited from two-day training seminars in Florida, New Mexico and Washington and represented numerous jurisdictions from 11 states.
The research demonstrates how persistent cultural stereotypes are, Correll said. Even students who displayed little bias when interviewed demonstrated otherwise when faced with a split-second decision.
“I may not believe it personally, but I am exposed to stereotypes constantly through media or social networks … (such as) the idea that young black men are dangerous,” he said. “Those associations can have an influence on my behavior even if I don’t believe them.”
The study found that police were considerably more accurate than students at correctly identifying a genuinely threatening suspect, as opposed to those brandishing a cell phone or wallet, perhaps a reflection of training. But officers were still influenced by the target’s race — an influence that may derive from the officers’ “contacts, attitudes and stereotypes,” Correll said.
For example, police who endorsed more violent stereotypes about Hispanics and those who overestimated the prevalence of violent crime in their districts demonstrated more bias to shoot Hispanic targets. That raises the question of whether police are responding to real-world threats — and whether that means some ethnic groups really are more likely to be armed and dangerous than others.
“That is a very sensitive question, whether or not (police officers’) reactions are based on some kind of truth. Is this police officers responding to reality on the ground? The short answer is, we don’t know,” Correll said. “But this research almost demands that we ask that question.”
The researchers’ recent findings were published in the Journal of Social Issues. The work was funded by a grant from the Russell Sage Foundation.
In 2007, Correll (then at the University of Chicago), Sadler (then at CU-Boulder), Park and Judd collaborated with the Denver Police Department on a widely cited study that found police officers were less influenced than the general public by racial bias and less likely than the general population to make a decision to shoot at African-American suspects wielding a benign object.
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CU team measures climate variability and conflict risk in East Africa
Oct 23rd
While a new study led by the University of Colorado Boulder shows the risk of human conflict in East Africa increases somewhat with hotter temperatures and drops a bit with higher precipitation, it concludes that socioeconomic, political and geographic factors play a much more substantial role than climate change.
According to CU-Boulder geography Professor John O’Loughlin, the new CU-Boulder study undertaken with the National Center for Atmospheric Research in Boulder is an attempt to clarify the often-contradictory debate on whether climate change is affecting armed conflicts in Africa. “We wanted to get beyond the specific idea and hype of climate wars,” he said. “The idea was to bring together a team perspective to see if changes in rainfall and temperature led to more conflict in vulnerable areas of East Africa.”
The research team examined extensive climate datasets from nine countries in East Africa, including the Horn of Africa, between 1990 and 2009: Burundi, Djibouti, Eritrea, Ethiopia, Kenya, Rwanda, Somalia, Tanzania and Uganda. The team also used a dataset containing more than 16,000 violent conflicts in those countries during that time period, parsing out more specific information on conflict location and under what type of political, social, economic and geographic conditions each incident took place.
The study, which included changes in precipitation and temperature over continuous six-month periods from 1949 to 2009, also showed there was no climate effect on East African conflicts during normal and drier precipitation periods or during periods of average and cooler temperatures, said O’Loughlin.
Moderate increases in temperature reduced the risk of conflict slightly after controlling for the influence of social and political conditions, but very hot temperatures increased the risk of conflict, said O’Loughlin. Unusually wet periods also reduced the risk of conflict, according to the new study.
“The relationship between climate change and conflict in East Africa is incredibly complex and varies hugely by country and time period,” he said. “The simplistic arguments we hear on both sides are not accurate, especially those by pessimists who talk about ‘climate wars’. Compared to social, economic and political factors, climate factors adding to conflict risk are really quite modest.”
The results are being published online Oct. 22 in the Proceedings of the National Academy of Sciences. Co-authors on the study include CU-Boulder Research Associate Frank Witmer and graduate student Andrew Linke as well as three scientists from the National Center for Atmospheric research — Arlene Laing, Andrew Gettelman and Jimy Dudhia. The National Science Foundation funded the study.
Much of the information on the 16,359 violent events in East Africa from 1990 to 2009 came from the Armed Conflict Location and Event Dataset, or ACLED, directed by Clionadh Raleigh of Trinity College in Dublin. The database covers individual conflicts from 1997 to 2009 in Africa, parts of Asia and Haiti – more than 60,000 violent incidents to date. Raleigh started the data collection while earning her doctorate at CU in 2007 under O’Loughlin.
In addition, more than a dozen CU-Boulder undergraduates spent thousands of hours combing online information sources like LexisNexis — a corporation that pioneered the electronic accessibility of legal and newspaper documents — in order to fill in details of individual violent conflicts by East African countries from 1990 to 1997. The student work was funded by the NSF’s Research Experiences for Undergraduates program.
The CU students coded each conflict event with very specific data, including geographic location coordinates, dates, people and descriptive classifications. The event information was then aggregated into months and into 100-kilometer grid cells that serve as the units of analysis for quantitative modeling.
Each conflict grid also was coded by socioeconomic and political characteristics like ethnic leadership, distance to an international border, capital city, local population size, well-being as measured by infant mortality, the extent of political rights, presidential election activity, road network density, the health of vegetation and crop conditions.
“The effects of climate variability on conflict risk is different in different countries,” O’Loughlin said. “Typically conflicts are very local and quite confined. The effects of climate on conflict in Ethiopia, for example, are different than those in Tanzania or Somalia. The idea that there is a general ‘African effect’ for conflict is wrong.”
The researchers used a variety of complex statistical calculations to assess the role of climate in violent conflict in East Africa, including regression models and a technique to uncover nonlinear influences and decrease “noise,” said O’Loughlin, also a faculty member at CU-Boulder’s Institute of Behavioral Science.
One component of the methods used by the team extracts predictions of individual instances of conflict from the statistical model and systematically compared them with the actual observations of conflict in the data, “a rigorous validity check,” he said.
Catastrophic conflicts like those in the “Great Lakes region” — Rwanda, Burundi, Uganda and the eastern Democratic Republic of the Congo — since the 1990s and the war with the Lord’s Resistance Army led by terrorist Joseph Kony that has been running since the late 1980s in northern Uganda and neighboring regions are marked with large red swaths on the maps.
Legacies of violence are extremely important for understanding and explaining unrest, he said. “Violence nearby and prior violence in the locality, especially for heavily populated areas, are the strongest predictors of conflict.”
Ongoing work is extending the study to all of sub-Saharan Africa since 1980 with a database of 63,000 violent events. Preliminary results from the work confirm the East African climate effects of higher than normal temperatures are increasing conflict risk.