Stories about: cancer

In zebrafish, a way to find new cancer therapies, targeting tumor promoters

A new study suggests the power of zebrafish as tools for cancer drug discovery (PHOTO: KATHERINE C. COHEN)

The lab of Leonard Zon, MD, has long been interested in making blood stem cells in quantity for therapeutic purposes. To test for their presence in zebrafish, their go-to research model, they turned to the MYB gene, a marker of blood stem cells. To spot the cells, Joseph Mandelbaum, a PhD candidate in the lab, attached a fluorescent green tag to MYB that made it easily visible in transparent zebrafish embryos.

“It was a real workhorse line for us,” says Zon, who directs the Stem Cell Research Program at Boston Children’s Hospital.

In addition to being a marker of blood stem cells, MYB is an oncogene. About five years ago, Zon was having lunch at a cancer meeting and, serendipitously, sat next to Jeff Kaufman, who was also interested in MYB. Kaufman was excited to hear about Zon’s fluorescing MYB zebrafish, which can be studied at scale and are surprisingly similar to humans genetically.

“Have you ever heard of adenoid cystic carcinoma?” he asked Zon.

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Super suppressor: Boosting a gene that stifles tumor growth

Researchers have packaged a tumor suppressor into a therapeutic nanoparticle.
Researchers have packaged a tumor suppressor into a therapeutic nanoparticle. IMAGE: ISLAM, ET AL.

Most of the time, cancer cells do a combination of two things: they overexpress genes that drive tumor growth and they lose normal genes that typically suppress tumors. No two tumors are exactly alike, but some combination of these two effects is usually what results in cancer. Now, for the first time, researchers have shown that it’s possible to treat cancer by delivering a gene that naturally suppresses tumors.

Researchers from Boston Children’s Hospital, Brigham and Women’s Hospital and Memorial Sloan Kettering Cancer Center combined their cancer biology and nanomaterials expertise and developed a therapeutic capable of delivering a tumor suppressor gene known as PTEN, the loss of which can allow tumors to grow unchecked.

In several preclinical models, their PTENboosting therapeutic was able to inhibit tumor growth. Their findings were published yesterday in Nature Biomedical Engineering.

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Typing medulloblastoma: From RNA to proteomics and phospho-proteomics

medulloblastoma proteomics study
Medulloblastoma (CREDIT: ARMED FORCES INSTITUTE OF PATHOLOGY/WIKIMEDIA)

Medulloblastoma is one of the most common pediatric brain tumors, accounting for nearly 10 percent of cases. It occurs in the cerebellum, a complex part of the brain that controls balance, coordination and motor function and regulates verbal expression and emotional modulation. While overall survival rates are high, current therapies can be toxic and cause secondary cancers. Developing alternative therapeutics is a priority for the field.

As early as the 1990s, the lab of Scott Pomeroy, MD, PhD, neurologist-in-chief at Boston Children’s Hospital, discovered molecules in medulloblastoma tumors that could predict response to therapies. In 2010, Pomeroy and colleagues uncovered four distinct molecular subtypes of medulloblastoma.

The World Health Organization updated the brain tumor classification scheme in 2016 to include these molecular and genetic features. In the new scheme, tumor subtypes with a good molecular prognosis receive less radiation and chemotherapy. But the creation of targeted therapeutics has remained a challenge, since some of the genetic pathways implicated in these subtypes are found in non-cancerous cells.

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Why are males more prone to bladder cancer than females?

A microscopic view of human testis tissue. Researchers have discovered why males are more likely to get bladder cancer than females.
A microscopic view of human testis tissue. Researchers have discovered why males are more likely to get bladder cancer than females. IMAGE: ADOBE STOCK

New research helps explain why men are three to five times more likely to develop bladder cancer than women.

Using mouse models and human patient data, Boston Children’s Hospital researchers in the urology department, Xue Sean Li, PhD, and Satoshi Kaneko, PhD, found that inherent genomic differences contribute to the contrast in bladder cancer rate between males and females.

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Putting patients first in the translational research pipeline

During a follow-up visit, pediatric hematologist/oncologist Sung-Yun Pai, MD, hugs a patient who received gene therapy for X-linked severe combined immunodeficiency.
During a follow-up visit at Dana-Farber/Boston Children’s Cancer and Blood Disorders Center, pediatric hematologist/oncologist Sung-Yun Pai, MD, hugs a patient who received gene therapy for X-linked severe combined immunodeficiency.

This is part II of a two-part blog series recapping the 2018 BIO International Convention. Read part I: Forecasting the convergence of artificial intelligence and precision medicine.

The hope to improve people’s lives is what drives many members of industry and academia to bring new products and therapies to market. At the BIO International Convention last week in Boston, there was lots of discussion about how translational science intersects with patients’ needs and why the best therapeutic developmental pipelines are consistently putting patients first.

As a case in point, Mustafa Sahin, MD, PhD, of Boston Children’s discussed his work to improve testing and translation of new therapies for autism spectrum disorder (ASD). As a member of PACT (Preclinical Autism Consortium for Therapeutics) and director of Boston Children’s Translational Neuroscience Program, Sahin aims to bridge the gap between drug discovery and clinical translation.

“Our mission is to de-risk entry of new therapies in the ASD drug discovery and development space,” said Sahin, who is also a professor of neurology at Harvard Medical School.

One big challenge, says Sahin, is knowing how well — or how poorly — autism therapies are actually affecting people with ASD. Externally, ASD is recognized by its core symptoms of repetitive behaviors and social deficits.

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Solving the DIPG puzzle a single cell at a time

Image depicting the cellular makeup of DIPG/DMG tumors vs normal brain tissue development
Scientists have discovered that DIPG/DMG tumors are made up of H3K27M-mutated cell populations that contain many cells stuck in a stem-cell-like state, fueling tumor growth. Cells that can differentiate despite the H3K27M mutation could hold the key to unlocking a new therapy for DIPG/DMG.

For more than 15 years, pediatric neuro-oncologist Mariella Filbin, MD, PhD, has been on a scientific crusade to understand DIPG (diffuse intrinsic pontine glioma). She hopes to one day be able to cure a disease that has historically been thought of as an incurable type of childhood brain cancer.

“While I was in medical school, I met a young girl who was diagnosed with DIPG,” Filbin recalls. “When I heard that there was no treatment available, I couldn’t believe that was the case. It really made a huge impression on me and since then, I’ve dedicated all my research to fighting DIPG.”

Her mission brought her to Boston Children’s Hospital for her medical residency program and later, to do postdoctoral research at the Dana-Farber/Boston Children’s Cancer and Blood Disorders Center. Now, she’s starting her own research laboratory focused on DIPG — which has also been called diffuse midline glioma (DMG) in recent years — and continuing to treat children with brain tumors at the Dana-Farber/Boston Children’s pediatric brain tumor treatment center. She’s also a scientist affiliated with the Broad Institute Cancer Program.

This year, Filbin has made new impact in the field by leveraging the newest single-cell genetic sequencing technologies to analyze exactly how DIPG develops in the first place. Her latest research, published in Science, entailed profiling more than 3,300 individual brain cells from biopsies of six different patients.

Using what’s known as a single-cell RNA sequencing approach to interrogate the makeup of DIPG/DMG tumors, Filbin was able to identify a particularly problematic type of brain cell that acts forever young, constantly dividing over and over again in a manner similar to stem cells.

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Trial shows chemotherapy is helping kids live with pulmonary vein stenosis

Magnification of pulmonary vein tissue showing signs of pulmonary vein stenosis (plump abnormal cells stained dark magenta).
Magnification of pulmonary vein tissue showing signs of pulmonary vein stenosis (plump abnormal cells stained dark magenta). Credit: Boston Children’s Hospital Department of Pathology

Pulmonary vein stenosis (PVS) is a rare disease in which abnormal cells build up inside the veins responsible for carrying oxygen-rich blood from the lungs to the heart. It restricts blood flow through these vessels, eventually sealing them off entirely if left untreated. Typically affecting young children, the most severe form of PVS progresses very quickly and can cause death within a matter of months after diagnosis.

Until recently, treatment options have been limited to keeping the pulmonary veins open through catheterization or surgery. Yet this approach only removes the cells but does nothing to prevent their regrowth. Now, a clinical trial shows that adding chemotherapy to a treatment regimen including catheterization and surgery can deter abnormal cellular growth and finally give children with PVS a chance to grow up.

Results of the trial, run by the Boston Children’s Hospital Pulmonary Vein Stenosis Program, were recently published in the Journal of Pediatrics.

“Through this approach, we’ve created the first-ever population of survivors who are living with severe PVS,” says Christina Ireland, RN, MS, FNP, who has managed enrolling patients in the trial and treating new patients since the trial ended. “We’ve changed this disease from an acute killer to a chronic, manageable condition.”

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A bold strategy to enhance CAR T-cell therapies, capable of targeting DIPG and other tough-to-treat cancers

CAR T-cell therapy uses a patient's own genetically modified T cells to attack cancer, as pictured here, where T cells surround a cancer cell.
T cells surround a cancer cell. Credit: National Institutes of Health

A Boston-based team of researchers, made up of scientists and pediatric oncologists, believe a better CAR T-cell therapy is on the horizon.

They say it could treat a range of cancers — including the notorious, universally-fatal childhood brain cancer known as diffuse intrinsic pontine glioma or DIPG — by targeting tumor cells in an exclusive manner that reduces life-threatening side effects (such as off-target toxicities and cytokine release syndrome). The team, led by Carl Novina, MD, PhD, and Mark Kieran, MD, PhD, of the Dana-Farber/Boston Children’s Cancer and Blood Disorders Center, calls their approach “small molecule CAR T-cell therapy.”

Their plan is to optimize the ability for CAR T-cell therapies, which use a patient’s genetically modified T cells to combat cancer, to more specifically kill tumor cells without setting off an immune response “storm” known as cytokine release syndrome. The key ingredient is a unique small molecule that greatly enhances the specificity of the tumor targeting component of the therapy.

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Two-drug approach halts lung tumors by starving them metabolically

(Illustration: Fawn Gracey)

Non-small-cell lung cancer is the leading cause of cancer death in the U.S. Roughly 1 in 4 cases are driven by the mutant KRAS oncogene. Though scientists have tried for more than three decades to target KRAS with drugs, they’ve had little success.

In a new study led by Nada Kalaany, PhD, and colleagues at Boston Children’s Hospital took a different approach, looking at what these deadly lung tumors need metabolically to live and grow. Reporting in the Proceedings of the National Academy of Sciences (PNAS), they show that a combination of two existing drugs can effectively starve tumors in a mouse model.

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The softer the nanoparticle, the better the drug delivery to tumors

Nanolipogels, pictured here, are a promising drug delivery system
Nanolipogels of different stiffness, as seen through a transmission electron microscope. Credit: Moses lab/Boston Children’s Hospital.

For the first time, scientists have shown that the elasticity of nanoparticles can affect how cells take them up in ways that can significantly improve drug delivery to tumors.

A team of Boston Children’s Hospital researchers led by Marsha A. Moses, PhD, who directs the Vascular Biology Program, created a novel nanolipogel-based drug delivery system that allowed the team to investigate the exclusive role of nanoparticle elasticity on the mechanisms of cell entry.

Their findings — that softer nanolipogels more efficiently enter cells using a different internalization pathway than their stiffer counterparts — were recently published in Nature Communications.

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