New pediatric digestive/liver disease gene identified by international team

A multinational team of researchers describes a newly identified cause of congenital diarrhea and liver disease in Read more

Tug of war between Parkinson’s protein and growth factors

A “tug of war” situation exists between Parkinson's provocateur protein alpha-synuclein and the growth factor Read more

From stinging to soothing: fire ant venom may lead to skin treatments

Compounds derived from fire ant venom can reduce skin thickening and inflammation in a mouse model of psoriasis, Emory and Case Western scientists have Read more

Jing Chen

Melanoma mutation likes fat for fuel

Cancer cells love glucose, the simple sugar the body uses for energy, so a high-fat, low-carb diet should starve them, right?

Where does this idea come from? Most cancer cells display enhanced glucose uptake, a phenomenon known as the Warburg effect, after 1931 Nobel Prize winner Otto Warburg.

Resurgent interest in exploiting the Warburg effect was described by Sam Apple in NYT Magazine and by Bret Stetka for NPR. High-fat, low-carb “ketogenic” diets are known to be effective against some types of epilepsy, and have also been explored by endurance athletes. Ketogenic diets have been tried as a clinical countermeasure against cancer in a limited way, mainly in brain cancer.

Before everybody gets too excited, let’s think about how particular cancer-driving mutations affect cell metabolism, suggests Winship Cancer Institute researcher Jing Chen. His team’s work in mice suggests that cancers with a common melanoma mutation (BRAF V600E) will grow faster in response to a ketogenic diet. In addition, the Winship researchers found that lipid-lowering agents such as statins curb these cancers’ growth, even in the context of a more normal diet.

The results were published on January 12 in Cell Metabolism.

Caveats: the findings cover just one mutation and need to be tested clinically.

Consumers and cancer patients already get a lot of advice about the right diet to fight cancer, but this research points toward an intriguing concept:  a “precision diet,” tailored to an individual patient’s cancer.  Read more

Posted on by Quinn Eastman in Cancer Leave a comment

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 by Quinn Eastman in Cancer 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 by Quinn Eastman in Cancer Leave a comment

Orange lichens are source for potential anticancer drug

An orange pigment found in lichens and rhubarb called parietin may have potential as an anti-cancer drug, scientists at Winship Cancer Institute of Emory University have discovered.

The results were published in Nature Cell Biology on October 19.

Caloplaca_Fenwick

Parietin, shown to have anticancer activity in the laboratory, is a dominant pigment in Caloplaca lichens. Note: this study did not assess the effects of eating lichens or rhubarb. Photo courtesy of www.aphotofungi.com

Parietin, also known as physcion, could slow the growth of and kill human leukemia cells obtained directly from patients, without obvious toxicity to human blood cells, the authors report. The pigment could also inhibit the growth of human cancer cell lines, derived from lung and head and neck tumors, when grafted into mice.

A team of researchers led by Jing Chen, PhD, discovered the properties of parietin because they were looking for inhibitors for the metabolic enzyme 6PGD (6-phosphogluconate dehydrogenase). 6PGD is part of the pentose phosphate pathway, which supplies cellular building blocks for rapid growth. Researchers have already found 6PGD enzyme activity increased in several types of cancer cells.

“This is part of the Warburg effect, the distortion of cancer cells’ metabolism,” says Chen, professor of hematology and medical oncology at Emory University School of Medicine and Winship Cancer Institute. “We found that 6PGD is an important metabolic branch point in several types of cancer cells.” Read more

Posted on by Quinn Eastman in Cancer Leave a comment

Melanoma mutation rewires cell metabolism

A mutation found in most melanomas rewires cancer cells’ metabolism, making them dependent on a ketogenesis enzyme, researchers at Winship Cancer Institute of Emory University have discovered.

The V600E mutation in the gene B-raf is present in most melanomas, in some cases of colon and thyroid cancer, and in the hairy cell form of leukemia. Existing drugs such as vemurafenib target the V600E mutation — the finding points to potential alternatives or possible strategies for countering resistance. It may also explain why the V600E mutation in particular is so common in melanomas.

Researchers led by Jing Chen and Sumin Kang have found that by promoting ketogenesis, the V600E mutation stimulates production of a chemical, acetoacetate, which amplifies the mutation’s growth-promoting effects. (A feedback mechanism! Screech!)

The results were published Thursday, July 2 in Molecular Cell.

More on this paper here.

Posted on by Quinn Eastman in Cancer 1 Comment

Potential anticancer drugs from humble sources

Jing Chen and colleagues at Winship Cancer Institute recently published a paper in Molecular Cell. Most of the paper deals with a metabolic enzyme, 6PGD (6-phosphogluconate dehydrogenase), and how it is more active in cancer cells.

Rhubarb_Flower

Rheum palmatum/Chinese rhubarb/da-huang

Tucked in at the end is a note that an inhibitor of 6GPD with an odd name, physcion, has anticancer activity in Chen’s team’s hands. Physcion, also known as parietin, is an orange-yellow pigment extractable from lichens and Chinese rhubarb that has been employed as an anti-mildew agent.

Probing cancer cells’ warped metabolism is a promising approach, for both drug discovery and finding effective ways to combine existing drugs, because of the Warburg effect: cancer cells’ tendency to suck up lots of sugar and use it in energy-inefficient ways. Read more

Posted on by Quinn Eastman in Cancer 1 Comment

Resurgence of interest in cancer cell metabolism

A recent article in Nature describes the resurgence of interest in cancer cell metabolism. This means exploiting the unique metabolic dependencies of cancer cells, such as their increased demand for glucose.

Cancer cells' preference for glucose is named after 1931 Nobelist Otto Warburg

Otto Warburg, who won the Nobel Prize in Medicine in 1931, noticed that cancer cells have a “sweet tooth” decades ago, but only recently have researchers learned enough about cancer cells’ regulatory circuitry to possibly use this to their advantage.

At Winship Cancer Institute of Emory University, several scientists have been investigating aspects of this phenomenon. Jing Chen and his team have identified a switch, the enzyme pyruvate kinase, which many types of cancer use to control glucose metabolism, and that might be a good drug target.

Jing Chen, PhD, and Taro Hitosugi, PhD

Shi-Yong Sun, Wei Zhou and their colleagues have found that cancer cells are sneaky: blockade the front door (for glucose metabolism, this means hitting them with the chemical 2-deoxyglucose) and they escape out the back by turning on certain survival pathways. This means combination tactics or indirectly targeting glucose metabolism through the molecule mTOR might be more effective, the Nature article says.

A quote from the article:

Clearly, metabolic pathways are highly interconnected with pathways that govern the hallmarks of cancer, such as unrestrained proliferation and resistance to cell death. The many metabolic enzymes, intermediates and products involved could be fertile ground for improving cancer diagnostics and therapeutics.

Posted on by Quinn Eastman in Cancer Leave a comment