A Bright New Method for Rapidly Screening Cancer Drugs

Illustration of red, green and blue fluorescent proteins.
Chemists have devised a new approach to screening cancer drugs that uses gold nanoparticles with red, green and blue outputs provided by fluorescent proteins. Credit: University of Massachusetts Amherst.

Scientists may screen billions of chemical compounds before uncovering the few that effectively treat a disease. But identifying compounds that work is just the first step toward developing a new therapy. Scientists then have to determine exactly how those compounds function.

Different cancer therapies attack cancer cells in distinct ways. For example, some drugs kill cancer cells by causing their outer membranes to rapidly rupture in a process known as necrosis. Others cause more subtle changes to cell membranes, which result in a type of programmed cell death known as apoptosis.

If researchers could distinguish the membrane alterations of chemically treated cancer cells, they could quickly determine how that chemical compound brings about the cells’ death. A new sensor developed by a research team led by Vincent Rotello Exit icon of the University of Massachusetts Amherst can make these distinctions in minutes. Continue reading

New Streamlined Technique for Processing Biological Samples

Illustration of Slug flow microextraction.
Researchers have discovered a faster, easier and more affordable technique for processing biological samples. Credit: Weldon School of Biomedical Engineering, Purdue University.

It’s not unusual for the standard dose of a drug to work well for one person but be less effective for another. One reason for such differences is that individuals can break down drugs at different rates, leading to different concentrations of drugs and of their breakdown products (metabolites) in the bloodstream. A promising new process Exit icon called slug-flow microextraction could make it faster, easier and more affordable to regularly monitor drug metabolites so that medication dosages could be tailored to each patient’s needs, an approach known as personalized medicine. This technique could also allow researchers to better monitor people’s responses to new drug treatments during clinical trials. Continue reading

Delivering Gene-Editing Proteins to Living Cells

Illustration of a DNA strand being cut by a pair of scissors.
Researchers are testing new ways to get gene editing proteins into living cells to potentially modify human genes associated with disease. Credit: Stock image.

Over the last two decades, exciting tools have emerged that allow researchers to cut and paste specific sequences of DNA within living cells, a process called gene editing. These tools, including one adapted from a bacterial defense system called CRISPR, have energized the research community with the possibility of using them to modify human genes associated with disease.

A major barrier to testing medical applications of gene editing has been getting the proteins that do the cutting into the cells of living animals. The main methods used in the laboratory take a roundabout route: Researchers push the DNA templates for making the proteins into cells, and then the cells’ own protein factories produce the editing proteins.

Researchers led by David Liu Exit icon from Harvard University are trying to cut out the middleman, so to speak, by ferrying the editing proteins, not the DNA instructions, directly into cells. In a proof-of-concept study, their system successfully delivered three different types of editing proteins into cells in the inner ears of live mice. Continue reading

Illuminating Biology

This time of year, lights brighten our homes and add sparkle to our holidays. Year-round, scientists funded by the National Institutes of Health use light to illuminate important biological processes, from the inner workings of cells to the complex activity of the brain. Here’s a look at just a few of the ways new light-based tools have deepened our understanding of living systems and set the stage for future medical advances.

RSV infected cell
A new fluorescent probe shows viral RNA (red) in an RSV-infected cell. Credit: Eric Alonas and Philip Santangelo, Georgia Institute of Technology and Emory University.

Visualizing Viral Activity

What looks like a colorful pattern produced as light enters a kaleidoscope is an image of a cell infected with respiratory syncytial virus (RSV) lit up by a new fluorescent probe called MTRIPS (multiply labeled tetravalent RNA imaging probes).

Although relatively harmless in most children, RSV can lead to bronchitis and pneumonia in others. Philip Santangelo of the Georgia Institute of Technology and Emory University, along with colleagues nationwide, used MTRIPS to gain a closer look at the life cycle of this virus.

Once introduced into RSV-infected cells, MTRIPS latched onto the genetic material of individual viral particles (in the image, red), making them glow. This enabled the researchers to follow the entry, assembly and replication of RSV inside the living cells. Continue reading

E. Coli Bacteria as Medical Sensors and Hard Drives?

E.Coli
Modified E. coli bacteria can serve as sensors and data storage devices for environmental and medical monitoring. Credit: Centers for Disease Control and Prevention. View larger image

E. coli bacteria help us digest our food, produce vitamin K and have served as a model organism in research for decades. Now, they might one day be harnessed as environmental or medical sensors and long-term data storage devices Exit icon.

MIT researchers Timothy Lu Exit icon and Fahim Farzadfard modified the DNA of E. coli cells so that the cells could be deployed to detect a signal (for example, a small molecule, a drug or the presence of light) in their surroundings. To create the modified E. coli, the scientists inserted into the bacteria a custom-designed genetic tool.

When exposed to the specified signal, the tool triggers a series of biochemical processes that work together to introduce a single mutation at a specific site in the E. coli’s DNA. This genetic change serves to record exposure to the signal, and it’s passed on to subsequent generations of bacteria, providing a continued record of exposure to the signal. In essence, the modified bacteria act like a hard drive, storing biochemical memory for long periods of time. The memory can be retrieved by sequencing the bacteria or through a number of other laboratory techniques. Continue reading

Forecasting Infectious Disease Spread with Web Data

Just as you might turn to Twitter or Facebook for a pulse on what’s happening around you, researchers involved in an infectious disease computational modeling project are turning to anonymized social media and other publicly available Web data to improve their ability to forecast emerging outbreaks and develop tools that can help health officials as they respond.

Mining Wikipedia Data

Screen shot of the Wikipedia site
Incorporating real-time, anonymized data from Wikipedia and other novel sources of information is aiding efforts to forecast and respond to emerging outbreaks. Credit: Stock image.

“When it comes to infectious disease forecasting, getting ahead of the curve is problematic because data from official public health sources is retrospective,” says Irene Eckstrand of the National Institutes of Health, which funds the project, called Models of Infectious Disease Agent Study (MIDAS). “Incorporating real-time, anonymized data from social media and other Web sources into disease modeling tools may be helpful, but it also presents challenges.”

To help evaluate the Web’s potential for improving infectious disease forecasting efforts, MIDAS researcher Sara Del Valle of Los Alamos National Laboratory conducted proof-of-concept experiments involving data that Wikipedia releases hourly to any interested party. Del Valle’s research group built models based on the page view histories of disease-related Wikipedia pages in seven languages. The scientists tested the new models against their other models, which rely on official health data reported from countries using those languages. By comparing the outcomes of the different modeling approaches, the Los Alamos team concluded that the Wikipedia-based modeling results for flu and dengue fever performed better than those for other diseases. Continue reading

Field Focus: Bringing Biology Into Sharper View with New Microscopy Techniques

Composite image of mitochondria in a cell
In this composite image of mitochondria in a cell, the left panel shows a conventional optical microscopy image, the middle panel shows a three-dimensional (3-D) STORM image with color indicating depth, and the right panel shows a cross-section of the 3-D STORM image. Credit: Xiaowei Zhuang laboratory, Howard Hughes Medical Institute, Harvard University. View larger image.

Much as a photographer brings distant objects into focus with a telephoto lens, scientists can now see previously indistinct cellular components as small as a few billionths of a meter (nanometers). By overcoming some of the limitations of conventional optical microscopy, a set of techniques known as super-resolution fluorescence microscopy has changed once-blurry images of the nanoworld into well-resolved portraits of cellular architecture, with details never seen before in biology. Reflecting its importance, super-resolution microscopy was recognized with the 2014 Nobel Prize in chemistry.

Using the new techniques, scientists can observe processes in living cells across space and time and study the movements, interactions and roles of individual molecules. For instance, they can identify and track the proteins that allow a virus to invade a cell or those that enable tumor cells to migrate to distant parts of the body in metastatic cancer. The ability to analyze individual molecules, rather than collections of molecules, allows scientists to answer longstanding questions about cellular mechanisms and behavior, such as how cells move along a surface or how certain proteins interact with DNA to regulate gene activity. Continue reading

Meet Alfred Atanda Jr.

Alfred Atanda Jr.
Credit: Cynthia Brodoway, Nemours/Alfred I. duPont
Hospital for Children
Alfred Atanda Jr.
Fields: Pediatric orthopedic surgery, sports medicine
Works at: Nemours/Alfred I. duPont Hospital for Children
Blogs: as Philly.com’s Sports Doc at http://bit.ly/sportsdoc Exit icon
Family fact: Youngest of seven children
Musical skills: Piano and trumpet
Kitchen talent: Baking chocolate desserts for his pediatrician wife and their two young children

As a kid, Alfred Atanda loved science, sports and tinkering. He dreamed of being a construction worker or an engineer. Today, he works on one of the most complex construction projects of all: the human body.

As a pediatric orthopedic surgeon, Atanda focuses on sports medicine and injuries to children. He has a special passion for young baseball pitchers who have torn the ulnar collateral ligament (UCL) in the elbow of their throwing arm.

This sort of injury is most often caused by overuse. Many small tears accumulate over a long period, resulting in pain and slower, less accurate pitches. Decades ago, this sort of damage occurred almost exclusively in elite athletes. Now, Atanda sees it in children as young as 12 years old. He aims not only to study and treat these injuries, but also to find ways to prevent them.

His Findings

Atanda was first introduced to research on UCL injuries while working alongside team physicians for the Phillies, the professional baseball team in Philadelphia. The physicians wanted to determine whether ultrasound imaging could detect early warning signs—slight anatomical changes in the ligament—before the damage became severe enough to warrant an operation known as Tommy John surgery.

The research focused on Phillies pitchers who had no pain or other symptoms of injury. The multi-year project showed that the UCL in the throwing elbows of these players got progressively thicker and weaker compared to the same ligament in the players’ nonthrowing elbows. The scientists concluded that these physical changes are caused by prolonged exposure to professional-level pitching.

Alfred Atanda Jr. with Joe Piergrossi
Atanda examines the elbow of a young patient. Courtesy: Cynthia Brodoway, Nemours/Alfred I. duPont Hospital for Children

Atanda wondered whether ultrasound imaging could also detect early signs of UCL damage in young pitchers—those in Little League through high school. There has been a dramatic rise in the number of young pitchers who are experiencing the same injuries and undergoing the same surgery as the pros.

Atanda secured funding for this project from an Institutional Development Award (IDeA). The IDeA program builds research capacities in states like Delaware, where Atanda works, that historically have received low levels of funding from the National Institutes of Health.

Atanda’s project began about a year ago, and has examined 55 young athletes so far.

“We found similar results to what we found with the Phillies,” Atanda says, indicating that the UCL in the throwing elbows of young athletes was noticeably thicker than the UCL in the nonthrowing elbows. And the damage seems progressive, he says: “We saw that these ligaments got thicker as the pitchers got older and had more pitching experience.”

The immediate goal of this project, which he hopes to continue for another 3 years, is prophylaxis. “We’re trying to prevent any kind of overuse elbow injuries and the need for Tommy John surgeries later on,” Atanda says. He also hopes to establish quantitative correlations between pitching behavior and anatomical changes.

Atanda also has longer-term aspirations. “My goal is to change the culture in sports for young athletes in general,” he says. “I want to show there are downsides to pitching so much.”

In addition to championing pitch count limits Exit icon recommended by the American Sports Medicine Institute, Atanda advises a focus away from excess competition and toward getting exercise, enjoying social inter­action, building self-confidence and having fun.

Atanda’s research is funded by the National Institutes of Health through grant P20GM103464

Content adapted from the NIGMS Findings magazine article Game Changer

Correcting a Cellular Routing Error Could Treat Rare Kidney Disease

AGT protein and peroxisomes in untreated and treated cells.
The altered AGT protein (red) and peroxisomes (green) appear in different places in untreated cells (top), but they appear together (shown in yellow) in cells treated with DECA (bottom). Credit: Carla Koehler/Reproduced with permission from Proceedings of the National Academy of Sciences USA. View larger image.

Our cells have organized systems to route newly created proteins to the places where they’re needed to do their jobs. For some people born with a rare and potentially fatal genetic kidney disorder called PH1, a genetically altered form of a particular protein mistakenly ends up in mitochondria instead of in another organelle, the peroxisome. This cellular routing error of the AGT protein results in the harmful buildup of oxalate, which leads to kidney failure and other problems at an early age.

In new work led by UCLA biochemist Carla Koehler Exit icon, researchers used a robotic screening system to identify a compound that interferes with the delivery of proteins to mitochondria. Koehler’s team Exit icon showed that adding a small amount of the compound, known as DECA, to cells grown in the laboratory prevented the altered form of the AGT protein from going to the mitochondria and sent it to the peroxisome. The compound also reduced oxalate levels in a cell model of PH1.

The team’s findings suggest that DECA, which is already approved by the Food and Drug Administration for treating certain bacterial infections, could be a promising candidate for treating children affected by PH1. And, Koehler notes, the screening strategy that she and her team used to identify DECA as a potential therapy may help researchers identify other new therapies for the disorder.

This work was funded in part by NIH under grant R01GM061721.

Molecules Known to Damage Cells May Also Have Healing Power

Free radicals in an ying-yang symbol
Biology in balance: Molecules called free radicals—like the peroxide molecules illustrated here—have a reputation for being dangerous. Now, they’ve revealed healing powers. In worms, at least. Credit: Stock image

When our health is concerned, some molecules are widely labeled “good,” while others are considered “bad.” Often, the truth is more complicated.

Consider free radical molecules. These highly reactive, oxygen-containing molecules are well known for damaging DNA, proteins and other molecules in our bodies. They are suspected of contributing to premature aging and cancer. But now, new research shows they might also have healing powers Exit icon.

Using the oft-studied laboratory roundworm known as C. elegans, a research group led by Andrew Chisholm Exit icon at the University of California, San Diego, made a surprising discovery. Free radicals, specifically those made in cell structures called mitochondria, appear necessary for skin wounds to heal. In fact, higher (but not dangerously high) levels of the molecules can actually speed wound closure.

If further research shows the same holds true in humans, the work could point to new ways to treat hard-to-heal wounds, like diabetic foot ulcers.

This work was funded in part by NIH under grants R01GM054657 and P40OD010440.