Stories about: Hematology/Oncology

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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Self-sacrificing cells hold clues to improving treatment of MRSA, sepsis

Image of neutrophils
During infection, white blood cells called neutrophils eject their own DNA strands outward to block bacteria from spreading. IMAGE: ADOBE STOCK

Over the last several years, scientists have made great headway in our understanding of how self-sabotaging immune cells play a role in our ability to fight infection. So far, we know that when white blood cells called neutrophils are triggered by bacterial infection, they self-combust and eject their own DNA strands outward like spider webs. Sacrificing themselves, the exploded neutrophils and their outreaching DNA tentacles form sunburst-shaped neutrophil extracellular traps (NETs).

“NET formation is an innate immune response that our body has when it recognizes the presence of pathogens,” says Ben Croker, PhD, a researcher in the Division of Hematology/Oncology at Boston Children’s Hospital. “Once formed, NETs restrict pathogen movement and proliferation and alert the rest of the immune system to the invader’s presence.”

Now, Croker and a team of researchers at Boston Children’s have identified a critical element of NET formation and how it enables the body to fight off infections like methicillin-resistant Staphylococcus aureus (MRSA). Their findings, recently published in Science Signaling, could someday have clinical implications for tough-to-treat infections and even sepsis.

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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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More surprises about blood development — and a possible lead for making lymphocytes

blood development chart
Blood development in the embryo begins with cells that make myeloid and erythroid cells – but not lymphoid cells. Why? A partial answer is in today’s Nature.

Hematopoietic stem cells (HSCs) have long been regarded as the granddaddy of all blood cells. After we’re born, these multipotent cells give rise to all our cell lineages: lymphoid, myeloid and erythroid cells. Hematologists have long focused on capturing HSCs’ emergence in the embryo, hoping to recreate the process in the lab to provide a source of therapeutic blood cells.

But in the embryo, oddly enough, blood development unfolds differently. The first blood cells to show up are already partly differentiated. These so-called “committed progenitors” give rise only to erythroid and myeloid cells — not lymphoid cells like the immune system’s B and T lymphocytes.

Researchers in the lab of George Q. Daley, MD, PhD, part of Boston Children’s Hospital’s Stem Cell Research program, wanted to know why. Does nature deliberately suppress blood cell multipotency in early embryonic development? And could this offer clues about how to reinstate multipotency and more readily generate different blood cell types?

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GALLERY: Forecasting the future of pediatric hematology/oncology

Title image for pediatric hematology/oncology predictionsRecently, the annual ASPHO (American Society for Pediatric Hematology/Oncology) meeting brought together more than 1,100 pediatric hematologists and oncologists, including a team from the Dana-Farber/Boston Children’s Cancers and Blood Disorders Center. Some of the delegates from Dana-Farber/Boston Children’s included:

Based on their discussions with their peers, these are their key takeaways from the meeting:

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Naturally-occurring molecule in tree leaves could treat anemia, other iron disorders

Hinoki cypress

“Without iron, life itself wouldn’t be feasible,” says Barry Paw, MD, PhD. “Iron transport is very important because of the role it plays in oxygen transport in blood, in key metabolic processes and in DNA replication.”

Although iron is crucial to many aspects of health, it needs the help of the body’s iron-transporting proteins. Which is why new findings reported in Science could impact a whole slew of iron disorders, ranging from iron-deficiency anemia to iron-overload liver disease. The team has discovered that a small molecule found naturally in Japanese cypress tree leaves, hinokitiol, can transport iron to overcome iron disorders in animals.

The multi-institutional research team is from the University of Illinois, Dana-Farber/Boston Children’s Cancer and Blood Disorders Center, Brigham and Women’s Hospital and Northeastern University. Paw, co-senior author on the new paper and a physician at Dana-Farber/Boston Children’s, and members of his lab demonstrated that hinokitiol can successfully reverse iron deficiency and iron overload in zebrafish disease models.

“Amazingly, we observed in zebrafish that hinokitiol can bind and transport iron inside or out of cell membranes to where it is needed most,” says Paw.

This gives hinokitiol big therapeutic potential.

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Science then & now: Progress that you can see

Click and drag to compare and contrast archive photos from the lab with current-day images of research at Boston Children’s Hospital.

Then, 1986: Stuart H. Orkin, MD, examines the DNA sequence of a gene.

Now, 2017: Today, Orkin is associate chief of Hematology/Oncology and chairman of Pediatric Oncology at Dana-Farber/Boston Children’s Cancer and Blood Disorders Center (DF/BC). In this photo, he examines a rendering of a gene regulatory molecule’s structure. Orkin’s lab investigates gene regulation of stem cell development, genetic vulnerabilities to cancer and gene and other therapies for treating hemoglobin disorders. 

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New cancer target, let-7, unifies theories on neuroblastoma’s origins

let7-arrows-target-shutterstock_368341574

Striking the nerve tissue, neuroblastoma is the most common cancer in infants and toddlers. Great strides have been made in its treatment, but advanced cases still are often fatal, and children who survive often face life-long physical and intellectual challenges related to their treatment.

A study published online by Nature last week, led by researchers at Dana-Farber/Boston Children’s Cancer and Blood Disorders Center, finds that a microRNA called let-7 is central in curbing neuroblastoma. The study unifies several theories about neuroblastoma and could bring focus to efforts to find a targeted, nontoxic alternative to chemotherapy.

The findings also have implications for other solid tumors in which let-7 is lost, such as Wilms tumor, lung, breast, ovarian and cervical cancers, says first author John Powers, PhD, of the Division of Pediatric Hematology/Oncology at Boston Children’s Hospital.

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