Warren symposium follows legacy of geneticist giant

If we want to understand how the brain creates memories, and how genetic disorders distort the brain’s machinery, then the fragile X gene is an ideal place to start. That’s why the Stephen T. Warren Memorial Symposium, taking place November 28-29 at Emory, will be a significant event for those interested in neuroscience and genetics. Stephen T. Warren, 1953-2021 Warren, the founding chair of Emory’s Department of Human Genetics, led an international team that discovered Read more

Mutations in V-ATPase proton pump implicated in epilepsy syndrome

Why and how disrupting V-ATPase function leads to epilepsy, researchers are just starting to figure Read more

Tracing the start of COVID-19 in GA

At a time when COVID-19 appears to be receding in much of Georgia, it’s worth revisiting the start of the pandemic in early 2020. Emory virologist Anne Piantadosi and colleagues have a paper in Viral Evolution on the earliest SARS-CoV-2 genetic sequences detected in Georgia. Analyzing relationships between those virus sequences and samples from other states and countries can give us an idea about where the first COVID-19 infections in Georgia came from. We can draw Read more
•••

drug discovery

Nutty stimulant revealed as anticancer tool

Arecoline — the stimulant component of areca nuts — has anticancer properties, researchers at Winship Cancer Institute of Emory University have discovered. The findings were published Thursday, November 17 in Molecular Cell.

areca-nut-and-arecoline

Areca nut and chemical structure of arecoline. From Wikimedia.

Areca nuts are chewed for their stimulant effects in many Asian countries, and evidence links the practice to the development of oral and esophageal cancer. Analogous to nicotine, arecoline was identified as an inhibitor of the enzyme ACAT1, which contributes to the metabolism-distorting Warburg effect in cancer cells.

Observers of health news have complained that coffee, as a widely cited example, is implicated in causing cancer one week and absolved the next. Arecoline is not another instance of the same trend, stresses senior author Jing Chen, PhD, professor of hematology and medical oncology at Emory University School of Medicine and Winship Cancer Institute.

“This is just a proof of principle, showing that ACAT1 is a good anticancer target,” Chen says. “We view arecoline as a lead to other compounds that could be more potent and selective.”

Chen says that arecoline could be compared to arsenic, a form of which is used as a treatment for acute promyelocytic leukemia, but is also linked to several types of cancer. Plus, arecoline’s cancer-promoting effects may be limited if it is not delivered or absorbed orally, he says. When arecoline first arose in a chemical screen, Chen says: “It sounded like a carcinogen to me. But it all depends on the dose and how it is taken into the body.” Read more

Posted on November 17, 2016 by Quinn Eastman in Cancer Leave a comment

Beyond CF – potential byproducts of precision medicine

Just a quick comment on the potential of research being conducted by Eric Sorscher, who came to Emory from University of Alabama, Birmingham in 2015 and is now a Georgia Research Alliance Eminent Scholar. While Sorscher’s lab is working on advancing new treatments for cystic fibrosis patients who currently do not benefit from available drugs, it was intriguing to learn of potential side benefits beyond cystic fibrosis.

Cystic fibrosis is caused by mutations in the CFTR gene, which encodes a protein with important functions in cells that produce mucus, sweat, saliva, tears and digestive enzymes. But other things can impair the functioning of the CFTR protein besides genetic mutations. Namely, smoking. Read more

Posted on February 22, 2016 by Quinn Eastman in Uncategorized Leave a comment

Rescuing existing antibiotics with adjuvants

One of the speakers at Thursday’s Antibiotic Resistance Center symposium, Gerald Wright from McMaster University, made the case for fighting antibiotic resistance by combining known antibiotics with non-antibiotic drugs that are used to treat other conditions, which he called adjuvants.

As an example, he cited this paper, in which his lab showed that loperamide, known commercially as the anti-diarrheal Immodium, can make bacteria sensitive to tetracycline-type antibiotics.

Wright said that other commercial drugs and compounds in pharmaceutical companies’ libraries could have similar synergistic effects when combined with existing antibiotics. Most drug-like compounds aimed at human physiology follow “Lipinski’s rule of five“, but the same rules don’t apply to bacteria, he said. What might be a more rewarding place to look for more anti-bacterial compounds? Natural products from fungi and plants, Wright proposed.

“I made a little fist-pump when he said that,” says Emory ethnobotanist Cassandra Quave, whose laboratory specializing in looking for anti-bacterial activities in medicinal plants.

Medical thnobotanist Cassandra Quave collecting plant specimens in Italy.

Medical ethnobotanist Cassandra Quave collecting plant specimens in Italy

Indeed, many of the points he made on strategies to overcome antibiotic resistance could apply to Quave’s approach. She and her colleagues have been investigating compounds that can disrupt biofilms, thus enhancing antibiotic activity. More at eScienceCommons and at her lab’s site.

Posted on January 15, 2016 by Quinn Eastman in Uncategorized Leave a comment

Anticancer drug strategy: making cells choke on copper

What do cancer cells have in common with horseshoe crabs and Mr. Spock from Star Trek?

They all depend upon copper. Horseshoe crabs have blue blood because they use copper to transport oxygen in their blood instead of iron (hemocyanin vs hemoglobin). Vulcans’ blood was supposed to be green, for the same reason.

Horseshoe Crab (Limulus polyphemus)

Horseshoe crabs and Vulcans use copper to transport oxygen in their blood. Cancer cells seem to need the metal more than other cells.

To be sure, all our cells need copper. Many human enzymes use the metal to catalyze important reactions, but cancer cells seem to need it more than healthy cells. Manipulating the body’s flow of copper is emerging as an anticancer drug strategy.

A team of scientists from University of Chicago, Emory and Shanghai have developed compounds that interfere with copper transport inside cells. These compounds inhibit the growth of several types of cancer cells, with minimal effects on the growth of non-cancerous cells, the researchers report in Nature Chemistry.

“We’re taking a tactic that’s different from other approaches. These compounds actually cause copper to accumulate inside cells,” says co-senior author Jing Chen, PhD, professor of hematology and medical oncology at Emory University School of Medicine and Winship Cancer Institute. Read more

Posted on November 9, 2015 by Quinn Eastman in Cancer Leave a comment

Cell death drug discovery: come at the king, you best not miss

It may seem like a stretch to compare an enzyme to a notorious criminal, especially one as distinctive as Omar Little, a character from the HBO drama The Wire played by Michael Kenneth Williams.

But stick with me, I’ll explain.

TheWire-OmarLittle2-Portable

Omar is a stick-up man who robs street-level drug dealers. When drug dealer henchmen Stinkum and Weebay ambush him, they are unsuccessful and Stinkum is killed. Omar tells Weebay, who is hiding behind a car: “Come at the king, you best not miss.”

At Emory, Ed Mocarski, Bill Kaiser and colleagues at GlaxoSmithKline have been studying an enzyme called RIP3. RIP3 is the king of a form of programmed cell death called necroptosis. RIP3 is involved in killing cells as a result of several inflammation-, infection- or injury-related triggers, so inhibitors of RIP3 could be useful in modulating inflammation in many diseases.

In a new Molecular Cell paper, Mocarski, Kaiser and their co-authors lay out what happened when they examined the effects of several compounds that inhibit RIP3 in cell culture. These compounds stopped necroptosis, but unexpectedly, they unleashed apoptosis, another form of programmed cell death.  Read more

Posted on November 20, 2014 by Quinn Eastman in Immunology Leave a comment

Rules of thumb for drug discovery

People interested in drug discovery may have heard of “Lipinski’s rule of five,” a rough-and-ready set of rules for determining whether a chemical structure is going to be viable as a orally administered drug or not. They basically say that if a compound is too big, too greasy or too complicated, it’s not going to get into the body and make it to the cells you want to affect. These guidelines have been the topic of much debate among medicinal chemists and pharmacologists.

The namesake for this set of rules, Chris Lipinski, will be speaking at Winship Cancer Institute Wednesday afternoon (4:30 pm, Nov 5, C5012) on “The Rule of 5, Public Chemistry-Biology Databases and Their Impact on Chemical Biology and Drug Discovery.” Lipinski spent most of his career at Pfizer (while there, he published the “rule of 5 paper“) and now is a consultant at Melior Discovery.

Posted on October 31, 2014 by Quinn Eastman in Cancer, Uncategorized Leave a comment

Hunting for potential diabetes drugs

Pathologist Keqiang Ye and his colleagues have been prolific in finding small molecules able to mimic the action of the brain growth factor BDNF. Aiming to export that success to similar molecules (that is, other receptor tyrosine kinases), they have been searching for potential drugs able to substitute for insulin.

Diabetes drugs Januvia (sitagliptin) and Lantus (insulin analog) are top 20 drugs, both in terms of dollars and monthly prescriptions, and the inconvenience of insulin injection is well known, so the business potential is clear.

A paper published in the journal Diabetes in April describes Ye’s team’s identification of a compound called chaetochromin A, which was originally isolated by Japanese researchers studying toxins found in moldy rice. Chaetochromin A can drive down blood sugar in normal, type 1 diabetes and type 2 diabetes mouse models, the authors show.

See here for another compound identified in Ye’s lab with similar properties.

Read more

Posted on July 9, 2014 by Quinn Eastman in Uncategorized Leave a comment

Two angles on cell death

One can take two very different angles when approaching Bill Kaiser’s and Ed Mocarski’s work on RIP kinases and the mechanisms of cell death. These are: the evolutionary where-does-apoptosis-come-from angle, and the anti-inflammatory drug discovery angle.

A pair of papers published this week, one in PNAS and one in Journal of Immunology, cover both of these angles. (Also, back to back papers in Cell this week, originating from Australia and Tennessee, touch on the same topic.)

First, the evolutionary angle.

Cellular suicide can be a “scorched earth” defense mechanism against viruses. Kaiser and Mocarski have been amassing evidence that some forms of cellular suicide arose as a result of an arms race of competition with viruses. The PNAS paper is part of this line of evidence. It shows that the cell-death circuits controlled by three different genes (RIP1, RIP3 and caspase 8) apparently can be lifted cleanly out of an animal. Mice lacking all three genes not only can be born, but have well-functioning immune systems.

Apoptosis is thought to be a form of cellular suicide important for the development of all multicellular organisms. That’s why, to cell and developmental biologists, it seemed rather shocking that researchers can mutate a group of genes that drive apoptosis and other forms of cellular suicide and have adult animals emerge.

Next, the drug discovery angle.

The J. Immunol paper makes that angle clear enough. Most of the authors on this paper are from GlaxoSmithKline’s “Pattern Recognition Receptor Discovery Performance Unit, Immuno-Inflammation Therapeutic Area.” Here, they show that a mutation in RIP1 inactivating the kinase enzyme protects mice against severe skin and multiorgan inflammation. They conclude their abstract with: “Together, these data suggest that RIP1 kinase represents an attractive therapeutic target for TNF-driven inflammatory diseases.”

Note: TNF-driven inflammatory diseases include rheumatoid arthritis, inflammatory bowel diseases and psoriasis, representing a multibillion dollar market.

 

Posted on May 13, 2014 by Quinn Eastman in Immunology Leave a comment

Moreno: how Big Pharma is slowing cancer research

Winship Cancer Institute’s Carlos Moreno has a sharply written commentary on Reuters, whipping Big Pharma for footdragging on cancer drug discovery for patent/IP-related reasons. Check it out.

Read more

Posted on April 1, 2014 by Quinn Eastman in Cancer Leave a comment

Dye me anticancer yellow

Over the last few years, pathologist Keqiang Ye and his colleagues have displayed an uncanny talent for finding potentially useful medicinal compounds. Recently another example of this talent appeared in Journal of Biological Chemistry.

Keqiang Ye, PhD

Postdoctoral fellow Qi Qi is first author on the paper. Collaborators include Jeffrey Olson, Liya Wang, Hui Mao, Haian Fu, Suresh Ramalingam and Shi-Yong Sun at Emory and Paul Mischel at UCLA.

Qi and Ye were looking for compounds that could inhibit the growth of an especially aggressive form of brain cancer, glioblastoma with deletion in the tumor suppressor gene PTEN. Tumors with this deletion do not respond to currently available targeted therapies.

The researchers found that acridine yellow G, a fluorescent dye used to stain microscope slides, can inhibit the growth of this tumor:

Oral administration of this compound evidently decreases the tumor volumes in both subcutaneous and intracranial models and elongates the life span of brain tumor inoculated nude mice. It also displays potent antitumor effect against human lung cancers. Moreover, it significantly decreases cell proliferation and enhances apoptosis in tumors…

Optimization of this compound by improving its potency through medicinal chemistry modification might warrant a novel anticancer drug for malignant human cancers.

Ye’s team observed that acridine yellow G appears not to be toxic in rodents. However, the acridine family of compounds tends to intercalate (insert itself) into DNA and can promote DNA damage, so more toxicology studies are needed. Other acridine family compounds such as quinacrine have been used to treat bacterial infections and as antiinflammatory agents, they note.

A paramecium stained with acridine orange, which shows anticancer activity for tumors containing PTEN mutations

Posted on February 23, 2012 by Quinn Eastman in Cancer Leave a comment
« Previous   1 2