Cold Spring Harbor Laboratory scientists trace a novel way cells are disrupted in cancer

A research team at Cold Spring Harbor Laboratory (CSHL) is clarifying a previously unappreciated way that cellular processes are disrupted in cancer.

Last year, scientists from the same CHSL team discovered that a "splicing factor" called SF2/ASF--a protein that changes the instructions for how other proteins are assembled--can induce tumors in cell cultures. The team's newly published results show that, in ways not yet fully understood, this same splicing factor acts on a group of other molecules that has long been known to affect cancer.

A Cascade of Molecular Interactions Leading to Cancer

Understanding such complex molecular interactions may one day lead to new approaches to cancer treatment. Cancers are enormously complex, and eventually, in most instances, they find ways of disrupting a large fraction of cellular processes. To untangle and reverse the changes, researchers seek to identify sequences of events in which molecules each affect one another in turn, ultimately inducing cancer-cell behavior.

For example, one protein may affect another by chemically disabling it, or by slowing the gene expression that produces it from the "instructions" contained in DNA. A drug that blocks any step in such a "pathway" has a chance to slow or prevent the disease.

Until recently, however, cancer researchers have paid scant attention to factors that affect others through "alternative splicing," a mechanism that changes how DNA instructions are cut and pasted together at the level of RNA intermediaries to form final templates for the production of proteins.

"Splicing is a critical step in gene expression," said Adrian R. Krainer, Ph.D., a CSHL professor who is an expert on RNA splicing. "Like other steps in gene expression, it seems to malfunction in cancer." Last year, Krainer and his colleagues found that several known splicing factors are present at higher-than-normal levels in some tumors. For example, a factor known as SF2/ASF was elevated in more than 20% of lung and colon tumors. Moreover, laboratory cultures of mouse or rat cells developed characteristics of tumors when they were programmed to make higher-than-normal levels of this splicing factor.

Changes in the PI3K-mTOR Pathway

In the new research, Krainer's team looked for specific molecules whose concentrations or enzymatic activities changed in cells in which SF2/ASF induced cancer. They found changes in some proteins in a group known as the PI3K-mTOR pathway, which is well known for its involvement in cancers.

The team speculated that SF2/ASF, as it influences how a gene's instructions are translated into protein, might cause a protein to be assembled without a key section that is normally modified by other proteins in the pathway. Krainer cautioned that the splicing factor may act on other proteins or in other ways in the cell, so further research is needed. Nonetheless, the team's research suggests that measuring SF2/ASF levels could eventually lead to a way to identify patients who will respond to existing drugs that block the PI3K-mTOR pathway.

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Very cold ice films in laboratory reveal mysteries of universe

The universe is full of water, mostly in the form of very cold ice films deposited on interstellar dust particles, but until recently little was known about the detailed small scale structure. Now the latest quick freezing techniques coupled with sophisticated scanning electron microscopy techniques, are allowing physicists to create ice films in cold conditions similar to outer space and observe the detailed molecular organisation, yielding clues to fundamental questions including possibly the origin of life. Researchers have been surprised by some of the results, not least by the sheer beauty of some of the images created, according to Julyan Cartwright, a specialist in ice structures at the Andalusian Institute for Earth Sciences (IACT) of the Spanish Research Council (CSIC) and the University of Granada in Spain.

Recent discoveries about the structure of ice films in astrophysical conditions at the mesoscale, which is the size just above the molecular level, were discussed at a recent workshop organised by the European Science Foundation (ESF) and co-chaired by Cartwright alongside C. Ignacio Sainz-Diaz, also from the IACT. As Cartwright noted, many of the discoveries about ice structures at low temperatures were made possible by earlier research into industrial applications involving deposits of thin films upon an underlying substrate (ie the surface, such as a rock, to which the film is attached), such as manufacture of ceramics and semiconductors. In turn the study of ice films could lead to insights of value in such industrial applications.

But the ESF workshop's main focus was on ice in space, usually formed at temperatures far lower than even the coldest places on earth, between 3 and 90 degrees above absolute zero (3-90K). Most of the ice is on dust grains because there are so many of them, but some ice is on larger bodies such as asteroids, comets, cold moons or planets, and occasionally planets capable of supporting life such as Earth. At low temperatures, ice can form different structures at the mesoscale than under terrestrial conditions, and in some cases can be amorphous in form, that is like a glass with the molecules in effect frozen in space, rather than as crystals. For ice to be amorphous, water has to be cooled to its glass transition temperature of about 130 K without ice crystals having formed first. To do this in the laboratory requires rapid cooling, which Cartwright and colleagues achieved in their work with a helium "cold finger" incorporated in a scanning electron microscope to take the images.

As Cartwright observed, ice can exist in a combination of crystalline and amorphous forms, in other words as a mixture of order and disorder, with many variants depending on the temperature at which freezing actually occurred. In his latest work, Cartwright and colleagues have shown that ice at the mesoscale comprises all sorts of different characteristic shapes associated with the temperature and pressure of freezing, also depending on the surface properties of the substrate. For example when formed on a titanium substrate at the very low temperature of 6K, ice has a characteristic cauliflower structure.

Most intriguingly, ice under certain conditions produces biomimetic forms, meaning that they appear life like, with shapes like palm leaves or worms, or even at a smaller scale like bacteria. This led Cartwright to point out that researchers should not assume that lifelike forms in objects obtained from space, like Mars rock, is evidence that life actually existed there. "If one goes to another planet and sees small wormlike or palm like structures, one should not immediately call a press conference announcing alien life has been found," said Cartwright.

On the other hand the existence of lifelike biomimetic structures in ice suggests that nature may well have copied physics. It is even possible that while ice is too cold to support most life as we know it, it may have provided a suitable internal environment for prebiotic life to have emerged.

"It is clear that biology does use physics," said Cartwright. "Indeed, how could it not do? So we shouldn't be surprised to see that sometimes biological structures clearly make use of simple physical principles. Then, going back in time, it seems reasonable to posit that when life first emerged, it would have been using as a container something much simpler than today's cell membrane, probably some sort of simple vesicle of the sort found in soap bubbles. This sort of vesicle can be found in abiotic systems today, both in hot conditions, in the chemistry associated with 'black smokers' on the sea floor, which is currently favoured as a possible origin of life, but also in the chemistry of sea ice."

This is an intriguing idea that will be explored further in projects spawned by the ESF workshop. This may provide a new twist to the idea that life arrived from space. It may be that the precursors of life came from space, but that the actual carbon based biochemistry of all organisms on Earth evolved on this planet.

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Ants may help researchers unlock mysteries of human aging process

NYU School of Medicine researcher Dr. Danny Reinberg was awarded a Howard Hughes Institute of Medicine Collaborative Innovation Award for new research on ant epigenetics- helping to unravel the impact lifestyle and environment have on genes. The research will investigate what ants can teach us about aging and behavior. Results of the ant study may translate to other species including humans, using gene regulation in ants as a model for aging.

"Ants live exceptionally long lives, they are social creatures, and they engage in stereotypical behaviors that befit their station in life, whether it be worker ant, soldier or queen," said Dr. Reinberg, professor of Biochemistry at NYU School of Medicine's Smilow Research Center. "Ants seem to be a perfect fit for study about whether epigenetics influences behavior and aging."

According to Dr. Reinberg, ants can assume either reproductive or non-reproductive roles in their colonies. The different reproductive roles also have a strong impact on the longevity of queens and workers. Released from the everyday activity of the colony and focused only on reproductive tasks, queens live up to 10 times longer than worker ants. As a consequence of differential aging and different behaviors, some regions of the queen's brain, such as the visual system, are not as well developed as those of the workers. Even though these two types of ants begin life remarkably similar, their individual experiences and differences in aging sculpt their brains and behaviors in vastly different ways. Reinberg hopes that it will be easier to pinpoint the changes in gene expression that drive the changes in adaptation to specific social roles in the ant community.

"I truly believe that this project will open the door for my next 20 years of science," said Dr. Reinberg, who is a Howard Hughes Medical Institute researcher at NYU and lead investigator for the award. Dr. Reinberg and his collaborators, Dr. Shelley L. Berger of The Wistar Institute and Dr. Juergen Liebig of Arizona State University, are one of eight scientific teams receiving research support through a $10 million pilot program, totaling $40 million over four years, from the Howard Hughes Medical Institute (HHMI).

Dr. Reinberg's and his collaborators' first goal is to deliver the first complete sequence of an ant genome. The group plans to sequence the genomes of three ant species in all. Researchers set out to discover whether changes in the brain and behavior occur as a consequence of living in a particular type of environment investigating the genetic underlying differences in longevity, social behavior and brain aging among queen and worker ants.

"Whether these modifications are indeed epigenetically inherited along with the gene is exactly what the team is seeking to discover in ants," said Dr. Reinberg. "There is not much known about epigenetic changes that may underlie behavior, but I intend to change that," concludes Dr. Reinberg.

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Unlocking mysteries of the brain with PET

Inflammatory response of brain cells as indicated by a molecular imaging technique could tell researchers more about why certain neurologic disorders, such as migraine headaches and psychosis in schizophrenic patients, occur and provide insight into how to best treat them, according to two studies published in the November issue of the Journal of Nuclear Medicine.

By using positron emission tomography (PET)a noninvasive molecular imaging technique researchers were to able to identify neuroinflammation, which is marked by activated microglia cells (brain cells that are responsive to injury or infection of brain tissue) in patients with schizophrenia and in animal models with migraines. Although neuroinflammation has been shown to play a major role in many neurodegenerative disorders such as multiple sclerosis, Parkinson's disease and Alzheimer's diseaseonly limited data exists about the role of neuroinflammation in schizophrenia and migraines. The two studies in the Journal of Nuclear Medicine are the first to identify neuroinflammation in specific regions of the brain a development which could be used to effectively evaluate the treatment response to anti-inflammatory drugs and become transformative for diagnosis and care.

"This study shows that molecular imaging can play an important role in better understanding the processes involving psychiatric and other neurological disorders," said Janine Doorduin, M.Sc., a researcher at the University Medical Center Groningen in the Netherlands and lead author of "Neuroinflammation in Schizophrenia-Related Psychosis: A PET Study." Doorduin added: "Without molecular imaging, the only way to look at inflammation in the brain, as well as other molecular processes, would be to use post-mortem brains."

Not much is known about the cause of schizophreniaa chronic and disabling brain disease characterized by psychotic episodes of delusions and hallucinations. Previously, evidence from post-mortem studies suggested the presence of activated microglia cells in the brain. However, the results of those studies were inconsistent. Using PET imaging to noninvasively image the living brains of schizophrenic patients, researchers in the Netherlands were able to pinpoint the neuroinflammation to an exact location in the brain, called the hippocampus. Now, researchers can target the hippocampus for further study and evaluate therapeutic treatments that could improve the quality of life for patients living with schizophrenia.

Likewise, PET imaging is also useful for identifying neuroinflammation associated with migraines. In the article, "11C-PK11195 PET for the In Vivo Evaluation of Neuroinflammation in the Rat Brain After Cortical Spreading Depression," researchers in Japan were the first to noninvasively visualize neuroinflammation in an animal model of migraine using a PET technique. Neuroinflammation is thought to be a key factor in the generation of pain sensation in migraine headaches. Observations from the study suggest that an inflammatory process may be involved in the pathologic state of migraines and that PET is a useful tool for evaluating the neurogenic inflammation in vivo.

"For physicians and patients, it is important to develop an objective method for the diagnosis of migraines and monitor therapeutic efficacy," said Yi-Long Cui, Ph.D., a researcher at the RIKEN Center for Molecular Imaging Science in Kobe, Japan, and lead author of the study. "The present study will bring about these possibilities to us since the PET probe used in the paper has already been applied to patients in other diseases."