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Cancer Drug Shortfalls Tied to How BET Inhibitors Hit BRD2 and BRD4 Differently
For more than a decade, BET inhibitors have been touted as one of cancer therapy’s most promising drug classes. The logic was straightforward: many tumors rely on oncogenes that depend on BET (bromo- and extra-terminal domain) proteins—chromatin‑binding regulators that help switch genes on. Block the BET family, the thinking went, and cancer cells should lose their transcriptional fuel. In the lab, the strategy often worked. But in clinical trials, the results were far more uneven: modest responses, substantial side effects, and little clarity about which patients might benefit.
A new study from the Max Planck Institute of Immunobiology and Epigenetics (MPI‑IE) may finally explain why. Published in Nature Genetics, the work uncovers a previously underappreciated division of labor within the BET family—one that helps clarify why drugs that block all BET proteins at once have struggled in the clinic. The paper is titled, “Histone acetylation-dependent clustering of BRD2 instructs transcription dynamics.”
Most BET inhibitors were designed to block a shared bromodomain that all BET proteins use to bind chromatin. That approach assumed the proteins—BRD2, BRD3, BRD4, and BRDT—perform similar roles. But the new study paints a more nuanced picture. Using rapid protein degradation, chemogenomics, and super‑resolution microscopy in mouse embryonic stem cells, the team dissected the distinct contributions of BRD2 and BRD4 to transcription.

Their findings reveal that BRD4 drives the well‑known step of releasing paused RNA polymerase II into productive elongation. BRD2, however, acts earlier. It helps recruit and organize the transcription initiation machinery at promoters, particularly under conditions where pause‑release is impaired. As the authors wrote, BRD2’s role becomes “particularly critical under the conditions of impaired pause release,” a mechanistic insight that reframes how BET proteins collaborate during gene activation.
The MPI‑IE team likens BRD2 to a stage manager. “BRD2 sets up the stage: assembling the props, costumes, and actors to ensure preparations run smoothly. BRD2 then gives BRD4, the actor, the ‘start’ signal to begin with the performance,” said senior author Asifa Akhtar, PhD. Blocking both proteins simultaneously—exactly what current BET inhibitors do—disrupts two different steps of transcription at once, producing unpredictable and context‑dependent effects.
“Our data shows that the setup work happening before is just as critical for gene activation,” explained Akhtar.
A key discovery is that BRD2’s recruitment depends on histone H4 acetylation placed by the enzyme MOF. When MOF was rapidly depleted or deleted, BRD2 lost its grip on chromatin, while BRD3 and BRD4 remained largely unaffected. “The findings support a model in which acetylated chromatin creates a platform that allows regulatory proteins like BRD2 to concentrate and prepare the transcription machinery,” noted first author Umut Erdogdu, PhD.
The team also showed that BRD2 forms dynamic clusters at promoters. Removing only the BRD2 region responsible for clustering stalled transcription almost as completely as deleting the entire protein.
The study suggests a path forward: instead of blocking all BET proteins indiscriminately, future therapies may need to distinguish between BRD2‑ and BRD4‑specific functions. “Thus, these findings support a model in which histone acetylation-dependent spatiotemporal dynamics of BRD2 coordinate the transcription machinery to regulate transcription initiation,” the authors wrote.
For a field long puzzled by the uneven performance of BET inhibitors, BRD2’s newly revealed role offers a compelling piece of the puzzle—and a clearer blueprint for next‑generation cancer therapeutics.
The post Cancer Drug Shortfalls Tied to How BET Inhibitors Hit BRD2 and BRD4 Differently 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.
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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Beyond sunshine: Iberia’s biotech moment has arrived with developing capital networks
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
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 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.”

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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