Stories about: Dana-Farber Boston Children’s

Sickle cell gene therapy to boost fetal hemoglobin: A 70-year timeline of discovery

sickled cells occluding a blood vessel
Sickled cells occluding a blood vessel. (Image: Elena Hartley)

Boston Children’s Hospital is now enrolling patients age 3 to 35 in a clinical trial of gene therapy for sickle cell disease. Based on technology developed in its own labs, it differs from other gene therapy approaches by having a two-pronged action. It represses production of the mutated beta hemoglobin that causes red blood cells to form the stiff “sickle” shapes that block up blood vessels. It also increases production of the fetal form of hemoglobin, which people normally stop making after birth.

Fetal hemoglobin doesn’t sickle and works fine for oxygen transport. The gene therapy being tested now restores fetal hemoglobin production by turning “off” a silencing gene called BCH11A.

BCL11A represses fetal hemoglobin and also activates beta hemoglobin, which is affected by the sickle-cell mutation,” David Williams, MD, the trial’s principal investigator, told Vector last year. Williams is also president of the Dana-Farber/Boston Children’s Cancer and Blood Disorders Center. “So when you knock BCL11A down, you simultaneously increase fetal hemoglobin and repress sickling hemoglobin, which is why we think this is the best approach to gene therapy in this disease.”

The therapy is the product of multiple discoveries, the first dating back 70 years. Click selected images below to enlarge.

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Cancer researchers hit a bullseye with a new drug target for Ewing sarcoma

Cell staining shows the lethal efficacy of CDK+PARP inhibitors against Ewing sarcoma
Fluorescent staining shows how PARP and CDK12 inhibitors combine to deal a lethal blow to Ewing sarcoma. In the top row, green represents locations of DNA damage incurred by Ewing sarcoma cells. In the bottom row, red represents DNA repair activity. Together, PARP and CDK12 inhibitors lead to Ewing sarcoma cell death.

Screening a class of recently-developed drug compounds — so-called “CDK inhibitors” capable of blocking CDK7/12/13 proteins — against hundreds of different human cancer cell lines, researchers at Dana-Farber/Boston Children’s Cancer and Blood Disorders Center have found that CDK12 inhibitors pack a particularly lethal punch to Ewing sarcoma, a rare cancer typically affecting children and young adults.

“No one has previously considered CDK12 inhibition as a way to combat Ewing sarcoma,” says Kimberly Stegmaier, MD, senior author of the new Cancer Cell paper that describes the findings.

In 2014, Nathaneal Gray, PhD, co-author on the new paper, and his team were the first to develop CDK inhibitors.

Some individuals were entirely cured of the disease

“Now, in mice, we’ve shown that Ewing sarcoma cells die if CDK12 is knocked out genetically or chemically inhibited,” Stegmaier says. What’s more, her team has discovered that CDK12 inhibition can be combined with another drug, called a PARP inhibitor, to double down on Ewing sarcoma cells.

The revelation that CDK12 inhibition can kill Ewing sarcoma cells brings a surge of hope to the field of pediatric oncology, which has long been challenged to find new drugs against childhood cancers.

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Dulling cancer therapy’s double-edged sword: A new way to block tumor recurrence

An immune cell engulfs cancer cells
An immune cell engulfs tumor cells.

Researchers have discovered that killing cancer cells can actually have the unintended effect of fueling the proliferation of residual, living cancer cells, ultimately leading to aggressive tumor progression.

The findings of the multi-institutional research team — including scientists from the Dana-Farber/Boston Children’s Cancer and Blood Disorders Center, Beth Israel Deaconness Medical Center and the Institute for Systems Biology — contradict the conventional approach to treating cancer.

In their study, published in the January issue of the Journal of Experimental Medicine, the researchers describe how chemotherapy or other targeted therapies create a build-up of tumor cell debris, comprised of dead, fragmented cancer cells. In animal models, the team observed that this cell debris sets off an inflammatory cascade in the body and also encourages lingering, living cancer cells to develop into new tumors.

“Our findings reveal that conventional cancer therapy is essentially a double-edged sword,” says co-senior author on the study Mark Kieran, MD, PhD, who directs the Pediatric Brain Tumor Program at Dana-Farber/Boston Children’s and is an associate professor of pediatrics at Harvard Medical School. “But more importantly, we also found a pathway to block the tumor-stimulating effects of cancer cell debris — using a class of mediators called resolvins.”

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Taking a sideswipe at high-risk neuroblastoma

Microscopy image of human neuroblastoma cells.
Human neuroblastoma cells.

Cancer and other diseases are now understood to spring from a complex interplay of biological factors rather than any one isolated origin. New research reveals that an equally-nuanced approach to treating high-risk neuroblastoma may be the most effective way to curb tumor growth.

One challenge in treating pediatric cancers like neuroblastoma is that they are not initiated from the same kinds of genetic mutations as adult cancers, which usually arise from mutations related to an accumulation of DNA replication errors or environmental factors. In contrast, childhood cancers more often stem from genetic duplications, deletions or translocations, the latter of which occurs when a gene sequence switches its location from one chromosome to another.

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Routing gene therapy directly into the brain

Image of mouse brain that received a transplantation of hematopoietic stem cells. The image shows the transplanted cells (green) rapidly engrafted and gave rise to new cells (also green) that have widely distributed throughout the entire brain. 
Image of a mouse brain that received a direct transplantation of hematopoietic stem cells. The image reveals the transplanted cells (green) rapidly engrafted and gave rise to new cells (also green) that have widely distributed throughout the entire brain.

A therapeutic technique to transplant blood-forming (hematopoietic) stem cells directly into the brain could herald a revolution in our approach to treating central nervous system diseases and neurodegenerative disorders.

The technique, which could be used to transplant donor-matched hematopoietic stem cells (HSCs) or a patient’s own genetically-engineered HSCs into the brain, was reported in Science Advances today by researchers from the Dana-Farber/Boston Children’s Cancer and Blood Disorders Center and the San Raffaele Telethon Institute for Gene Therapy.

In their study, the team tested the technique in a mouse model to treat lysosomal storage disorders, a group of severe metabolic disorders that affect the central nervous system.

The team’s findings are groundbreaking because, until now, it was thought that HSCs — from a healthy, matched donor or a patient’s own genetically-corrected cells — needed to be transplanted indirectly

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MATCHing precision medicine to all kids with cancer

Image of human neuroblastoma tumor cells. A new nationwide clinical trial called pediatric MATCH will utilize genomic sequencing to match children with individualized, targeted drugs matched to their tumor profile.
Human neuroblastoma cells.

A multi-center clinical trial is now offering nationwide genetic profiling services to pediatric and young adult cancer patients across the U.S. The goal is to identify gene mutations that can be individually matched with targeted drugs.

“This is the first-ever nationwide precision medicine clinical trial for pediatric cancer,” says pediatric oncologist Katherine Janeway, MD, clinical director of the solid tumor center at Dana-Farber/Boston Children’s Cancer and Blood Disorders Center.

Sponsored by the National Institute of Cancer (NCI) and the Children’s Oncology Group (COG), the so-called NCI-COG Pediatric MATCH trial will screen patients’ tumors for more than 160 gene mutations related to cancer. Nearly 1,000 patients are expected to participate in the trial and it is estimated that 10 percent of those patients will be matched with a targeted therapy.

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Gene therapy halts progression of cerebral adrenoleukodystrophy in clinical trial

David Williams, MD, the principal investigator of the clinical trial, discusses gene therapy and its impact on children with adrenoleukodystrophy

Adrenoleukodystrophy — depicted in the 1992 movie “Lorenzo’s Oil” — is a genetic disease that most severely affects boys. Caused by a defective gene on the X chromosome, it triggers a build-up of fatty acids that damage the protective myelin sheaths of the brain’s neurons, leading to cognitive and motor impairment. The most devastating form of the disease is cerebral adrenoleukodystrophy (CALD), marked by loss of myelin and brain inflammation. Without treatment, CALD ultimately leads to a vegetative state, typically claiming boys’ lives within 10 years of diagnosis.

But now, a breakthrough treatment is offering hope to families affected by adrenoleukodystrophy. A gene therapy treatment effectively stabilized CALD’s progression in 88 percent of patients, according to clinical trial results reported in the New England Journal of Medicine. The study was led by researchers from the Dana-Farber/Boston Children’s Cancer and Blood Disorders Center and Massachusetts General Hospital.

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“Vampires” may have been real people with this blood disorder

Mural of Vlad the Impaler, who was accused of being a vampire. Perhaps, instead, he suffered from a blood disorder called porphyria.Porphyrias, a group of eight known blood disorders, affect the body’s molecular machinery for making heme, which is a component of the oxygen-transporting protein, hemoglobin. When heme binds with iron, it gives blood its hallmark red color.

The different genetic variations that affect heme production give rise to different clinical presentations of porphyria — including one form that may be responsible for vampire folklore.

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Landmark moment for science as the FDA approves a gene therapy for the first time

Leukemia blast cells, which could now be destroyed using a first-of-its-kind, FDA-approved gene therapy called CAR-T cell therapy
Leukemia blast cells.

Today, the Food and Drug Administration approved a gene therapy known as CAR T-cell therapy that genetically modifies a patient’s own cells to help them combat pediatric acute lymphoblastic leukemia (ALL), the most common childhood cancer. It is the first gene therapy to be approved by the FDA.

“This represents the progression of the field of gene therapy, which has been developing over the last 30 years,” says gene therapy pioneer David A. Williams, MD, who is chief scientific officer of Boston Children’s Hospital and president of the Dana-Farber/Boston Children’s Cancer and Blood Disorders Center. “It’s a realization of what we envisioned to be molecular medicine when this research started. The vision — that we could alter cells in a way to cure disease — is now coming true.”

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CRISPR enables cancer immunotherapy drug discovery

Artwork depicting cancer cells with different genes deleted by CRISPR-Cas9, performed to identify novel cancer immunotherapy targets
These cancer cells (colored shapes) each have a different gene deleted through CRISPR-Cas9 technology. In a novel genetic screening approach, the T cells (red) destroy those cancer cells that have lost genes essential for evading immune attack, revealing potential drug targets for enhancing PD-1-checkpoint-based cancer immunotherapy. Credit: Haining Lab 

A novel screening method using CRISPR-Cas9 genome editing technology has revealed new drug targets that could potentially enhance the effectiveness of PD-1 checkpoint inhibitors, a promising new class of cancer immunotherapy.

The method, developed by a team at Dana-Farber/Boston Children’s Cancer and Blood Disorders Center, uses CRISPR-Cas9 to systematically delete thousands of tumor genes to test their function in a mouse model. In findings published today by Nature, researchers led by pediatric oncologist W. Nick Haining, BM, BCh report that deletion of one gene, Ptpn2, made tumor cells more susceptible to PD-1 checkpoint inhibitors. Other novel drug targets are likely around the corner.

PD-1 inhibition “releases the brakes” on immune cells, enabling them to locate and destroy cancer cells. But for many patients, it’s not effective enough on its own.

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