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Targeting Metabolic Mechanism Restores Chemotherapy Sensitivity in Ovarian Cancer

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Although many cancers can be successfully treated using platinum-based chemotherapies, which work by damaging DNA, a subset avoid cell death by repairing their own DNA. Ovarian cancers are an example. Patients whose tumors are DNA repair proficient historically face poor prognosis and their tumors commonly recur within months. 

Now data from a new study done in cells and mice points to a potential metabolic target that could prevent tumor cells from repairing their own DNA, thus overcoming their resistance. The work was done by scientists from The Wistar Institute, Temple University, and their collaborators elsewhere. Details are published in a new Nature paper titled “αKG-mediated carnitine synthesis drives DNA repair via histone acetylation.” In it, they describe a metabolic process that is altered in cancer cells that makes them resistant to DNA-damaging agents. They have also identified a drug that can inhibit the pathway that may offer a strategy for overcoming chemotherapy resistance. 

Specifically, the study centers on alpha-ketoglutarate (αKG), a metabolite which accumulates in DNA repair proficient ovarian tumors. First, the scientists confirmed αKG’s role in helping ovarian cancer cells repair DNA and survive chemotherapy treatment. They did this by using a CRISPR-based approach to systematically search for the enzyme that enables αKG to repair DNA. 

Previous studies on αKG focused on its role in demethylation of proteins and other molecules. Though the scientific literature pointed towards demethylases as the key enzyme, the scientists focused onTMLHE, an enzyme that initiates the synthesis of carnitine, a molecule often associated with energy metabolism. “Finding TMLHE was the moment I thought, ‘Okay, this is going to be something bigger than what we expected,’” said Katherine Aird, PhD, professor and co-leader of the molecular and cellular oncogenesis program at The Wistar Institute and senior author of the study.

The data indicated that elevated αKG activates TMLHE, which drives carnitine production. Carnitine then carries acetyl groups out of the mitochondria and into the nucleus where they are deposited onto histones. This loosens the DNA-histone complex which allows the cells repair machinery to access and fix DNA damage. 

Next the team showed that when TMLHE or carnitine synthesis is blocked, histone acetylation does not occur which prevents the DNA repair machinery from doing its work. In these cases, the cells become significantly more sensitive to DNA-damaging chemotherapies. “The connection between αKG and methylation is well established—that’s what everyone studies,” said Nathaniel Snyder, PhD, associate professor in the Aging + Cardiovascular Discovery Center at Temple University School of Medicine. “What we found is that αKG is also controlling acetylation through a completely separate route, and that route turns out to be essential for DNA repair. That’s a new piece of biology that nobody had described before.”

As part of the study, the scientists tested the effects of mildronate, a carnitine synthesis inhibitor, and cisplatin, a platinum-based DNA-damaging chemotherapy drug. They found that the combination of these treatments reduced the tumor burden in mouse models of ovarian cancer, while neither drug alone produced a significant effect. Additionally, patients with high TMLHE expression in tumor tissue had significantly worse progression-free survival post chemotherapy, and higher serum acetylcarnitine levels at diagnosis correlated with faster disease progression. 

That latter finding suggests that it may one day be possible to use a routine blood test for circulating acetylcarnitine to identify patients that are most likely to resist standard platinum-based cancer treatments, and to benefit from a combination therapy. 

The post Targeting Metabolic Mechanism Restores Chemotherapy Sensitivity in Ovarian Cancer appeared first on GEN – Genetic Engineering and Biotechnology News.

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STAT+: At hospital finance conference, a call to end the friction that’s keeping costs high

NATIONAL HARBOR, Md. — At this week’s annual meeting of hospital finance leaders, the exhibit hall was packed with dozens of billing and collections companies. Armed with candy, tote bags, and pens, they smiled at passersby, eager to explain why their tactics would extract the most money from health insurers. 

The sheer number of “revenue cycle” vendors who attended the Healthcare Financial Management Association’s annual conference in Maryland — outnumbering even the hospital attendees, according to a list shared by an organizer — was a visible reminder of the enormous industry built around just paying medical bills. 

The U.S. health care industry spends roughly $200 billion annually on financial transactions: claims processing, payment, collections, and prior authorization. And yet the proliferation of billing vendors seemed to clash with the main theme of HFMA’s conference, affordability, spotlighting the need to simplify the billing process so that health care is less costly and more accessible for patients. 

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NATIONAL HARBOR, Md. — At this week’s annual meeting of hospital finance leaders, the exhibit hall was packed with dozens of billing and collections companies. Armed with candy, tote bags, and pens, they smiled at passersby, eager to explain why their tactics would extract the most money from health insurers. 

The sheer number of “revenue cycle” vendors who attended the Healthcare Financial Management Association’s annual conference in Maryland — outnumbering even the hospital attendees, according to a list shared by an organizer — was a visible reminder of the enormous industry built around just paying medical bills. 

The U.S. health care industry spends roughly $200 billion annually on financial transactions: claims processing, payment, collections, and prior authorization. And yet the proliferation of billing vendors seemed to clash with the main theme of HFMA’s conference, affordability, spotlighting the need to simplify the billing process so that health care is less costly and more accessible for patients. 

Continue to STAT+ to read the full story…

Read More

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Beyond sunshine: Iberia’s biotech moment has arrived with developing capital networks

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Strong science, lower costs and growing capital networks are putting Spain and Portugal on the biotech investment map, even as structural bottlenecks persist, according to two investors.

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Laser‑Driven Phase Contrast Enhances Cryo‑EM Resolution of Small Proteins

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You know when you are at the eye doctor getting an updated prescription, and suddenly the world snaps into sharper focus? Physicists at the University of California (UC), Berkeley, have now done something similar for electron microscopy. By introducing phase contrast into a cryo‑electron microscope, they have delivered dramatically sharper images of some of biology’s smallest and most elusive proteins.

The advance comes from a new laser phase plate (LPP), described in the paper “Laser phase plate improves structure determination of small proteins by cryo‑EM,” which was published recently in Science. Led by physicist Holger Mueller, PhD, of UC Berkeley and Lawrence Berkeley National Laboratory, the team demonstrated that a laser‑driven phase plate can overcome one of cryo‑EM’s most persistent limitations: poor contrast for small proteins.

Cryo-EM images of two proteins, apoferritin and hemoglobin, taken without and with a laser phase plate. The images are analyzed in a computer to produce detailed 3D structures of the proteins. [Holger Müller, Jessie Zhang/UC Berkeley]

Cryo‑EM has transformed structural biology over the past decade, earning a Nobel Prize in 2017 for enabling high‑resolution structures without crystallization. But despite its impact, the technique still struggles with proteins below ~70 kilodaltons—a size range that includes about 90% of the human proteome. “Because of signal-to-noise limitations, the majority of human and animal proteins are too small to be analyzed by these methods [cryo-EM and cryoelectron tomography]. The increase in signal-to-noise ratio provided by this laser phase plate is expected to overcome these important limitations.”

The new LPP begins to address that problem. The LPP uses an intense, continuous‑wave laser to shift the phase of the electron beam itself. This produces true phase contrast without dimming or destabilizing the beam. Mueller described the laser focus as “75 kilowatts focused to a few microns… That’s more powerful than what you use for welding. It has more power than a military laser. It builds up the brightest continuous laser focus ever.”

Installed in a custom Thermo Fisher Titan Krios, the LPP immediately improved the clarity and resolvability of small proteins, including hemoglobin, which sits at the lower limit of what today’s cryo‑EM instruments can handle. As the authors wrote in the abstract: “Here, we show that the laser phase plate (LPP)… enhances the resolution in single-particle reconstruction of small proteins by improving specimen-motion correction, recovery of information from the early frames, as well as particle visualization, 3D classification, and alignment.”

phase plate cover Cryo-EM
A laser (purple) is powerfully amplified by highly polished mirrors and focused on the electron beam (blue) to shift its phase and increase the cryo-EM microscope’s contrast, allowing biologists to image smaller proteins and the crowded structures inside cells. [Sayo Studio]

These improvements were achieved using standard defocus ranges and reconstruction workflows. “For the most challenging cases—small particles, bad specimens—the laser produces a very considerable advantage,” Mueller said.

 

The impact extends beyond single‑particle analysis. Cryo‑electron tomography (cryo‑ET), which assembles multiple angular views of a molecule or protein into a three-dimensional image, stands to benefit even more. “With cryo-ET, we’re looking at small, very complicated cellular material that’s incredibly crowded inside the cell,” said Bridget Carragher, PhD, founding technical director of imaging at Biohub. “It’s like a forest of trees, and you’re trying to find one leaf on one tree in there. Cryo-ET needs a dramatic step forward in contrast, so we can start to see what’s going on inside the cell. That’s what the laser phase plate promises to give us.”

Biohub is developing a dual‑laser version of the system, designed to reduce component wear and minimize aberrations. Meanwhile, Mueller’s team is pushing toward imaging proteins as small as 17 kilodaltons, a threshold that would open access to vast regions of the human proteome previously invisible to cryo‑EM.

“This technology is a step function change for biology,” said Stephani Otte, PhD, Biohub’s vice president of imaging science. “What was once invisible will become visible—and that changes everything about how we understand disease.”

“The bottom line is, if you have a large protein and a really good sample—a fresh one or one frozen without bubbles, for example—you may not need the phase plate to get a single, high-quality image. But for a small protein and a bad sample, laser-on is best,” Mueller said. “This could fill an enormous gap in our knowledge of protein structures that can’t be crystallized or are too small for today’s cryo-EM. And it will be revolutionary for cryo-ET.”

The post Laser‑Driven Phase Contrast Enhances Cryo‑EM Resolution of Small Proteins appeared first on GEN – Genetic Engineering and Biotechnology News.

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