Cancer

Expanding cytotoxic T lymphocytes from umbilical cord blood to target three viruses

/in , , , /by
PDF Version

What’s Known
Children’s National Health System is the only pediatric hospital in the nation that grows personalized T-cells from naïve cord blood (CB), training these CB-derived cells to simultaneously fight adenovirus, cytomegalovirus, and Epstein-Barr virus to control viral infections after transplantation. Here are a number of the critical steps during that three-month manufacturing process.

T Cell Isolation Process

Source: P.J. Hanley, J. J. Melenhors, S. Nikiforow, P. Scheinberg, J.W. Blaney, G. Demmler-Harrison, C.R. Cruz, S. Lam, R.A. Krance, K.S. Leung, C.A. Martinez, H. Liu, D.C. Douek, H.E. Heslop, C. M. Rooney, E.J. Shpall, A.J. Barrett, J.R. Rodgers, and C.M. Bollard. “CMV-Specific T-Cells Generated From Naïve T-Cells Recognize Atypical Epitopes and May Be Protective In Vivo.” Published by Science Translational Medicine on April 29, 2015

New research shows success training t-cells to recognize and fight life-threatening viruses

/in , , , /by

Children's is the only U.S. pediatric hospital that manufactures specialized T-cells from native cord blood

Patients with leukemia, lymphoma, other cancers, and genetic disorders who receive stem cell or cord blood transplants face the post-transplant risk of developing a life-threatening infection with adenovirus, cytomegalovirus (CMV), or Epstein-Barr virus (EBV).

The study reports the results of a head-to-head comparison of two powerful immunotherapeutic strategies to thwart such viral infections. Both therapeutic approaches leverage the power of multivirus-specific, donor-derived T-cells (mCTL), which are highly skilled at recognizing foreign invaders and, in the case of the peripheral blood cells, have long memories of past battles.

The award-winning paper, “Multivirus-Specific T Cells From Both Cord Blood and Bone Marrow Transplant Donors” was presented during the International Society for Cellular Therapy (ISCT) 2016 Annual Meeting, held from May 25 through May 28, in Singapore. The abstract’s lead author, Patrick J. Hanley, PhD, Laboratory Facility Director of Children’s Cellular Therapy and Stem Cell Processing facility, was recognized by ISCT with a Young Investigator award during the meeting.

Nine research scientists and clinicians affiliated with Children’s National Health System are co-authors of a paper, including Michael D. Keller, MD, the lead clinical investigator of the peripheral blood T-cell study, and Catherine M. Bollard, MBChB, MD, the study’s sponsor and Director of Children’s National Program for Cell Enhancement and Technologies for Immunotherapy.

After certain treatments, some cancer patients’ bodies are stripped of their natural ability to fight infection. The stem cell or the cord blood transplant restores the body’s ability to produce a full complement of blood cells, including infection-fighting white blood cells. As a further boost to these patients, the T-cells are trained to spot and neutralize all three potentially lethal viruses (CMV, EBV, and adenovirus) simultaneously. The personalized cell therapy can be accomplished in a single infusion and administered in the outpatient setting.

In the phase I perspective study, the personalized T-cells were grown from peripheral blood (PB) of adult donors who were seropositive for CMV, a relative of the virus that causes chickenpox, and were also coaxed to grow from naïve cord blood (CB). These naïve cells need additional training since they have never been to battle.

Since the mid-1990s, PB has been shown to be effective for such use. Hanley says that fewer than one dozen facilities in the United States perform PB antiviral T-cell infusions. Of that selective group, Children’s National is the only U.S. location that also grows the specialized T-cells from naïve CB, a procedure that takes a bit longer to accomplish but can help patients whose blood type is in short supply.

Thirteen patients were infused with PB mCTL, and 12 patients were infused with the T-cells derived from cord blood. Patients received their transfusions from 35 to 384 days after their stem cell or cord blood transplant. Within four weeks, the research team saw up to a 160-fold increase in virus-specific T-cells, a development that coincided with patients’ response to therapy. “The overall … response rate in both groups was 81 percent,” writes Hanley and colleagues.

Eight patients had a complete response. Five had a partial response. Nine remain free of infection/reactivation. What’s more, the patients’ restored immunity was durable with at least one patient remaining free of infection two years after treatment – without the need for pharmaceuticals administered in a hospital setting, which exacts a higher overall cost to the healthcare system.

“This study demonstrates that mCTL derived from the PB of seropositive donors, as well as the CB of virus naïve donors, expand in vivo and are active against multiple viruses. Furthermore, by restoring immunity to multiple viruses simultaneously, the need for continued prophylaxis with pharmacotherapy is eliminated, thus, improving the efficiency and cost-effectiveness of protecting SCT and CBT recipients from these potentially lethal viruses,” Hanley and co-authors conclude.

Related Resources: Research at a Glance

Analysis of a progressive diffuse intrinsic pontine glioma: a case report

/in , , , , , /by

rg_histological-dipg-image

PDF Version

What’s Known
Despite multiple clinical trials testing an assortment of new treatments, the survival rate for diffuse intrinsic pontine glioma (DIPG) remains abysmal, with most children succumbing to the pediatric brainstem tumor within 12 months of diagnosis. Focal radiation therapy, the primary treatment approach, has not improved overall survival. While the majority of DIPG tumors grow within the brainstem, metastases can occur elsewhere in the brain. Due to recent availability of tissue, new data are emerging about the biologic behavior of tumors, details that could be instrumental in constructing optimal treatment strategies.

What’s New
An otherwise healthy 9-year-old girl developed weakness in the left side of her face; magnetic resonance imagining revealed T2/FLAIR hyperintensity centered within and expanding the pons. Despite various treatments, her pontine lesion increased in size and new metastases were noted. The team led by Children’s National Health System researchers is the first to report comprehensive phenotypic analyses comparing multiple sites in primary and distant tumors. All tumor sites displayed positive staining for the H3K27M mutation, a mutation described in more than two-thirds of DIPGs that may portend a worse overall survival. Persistence of mutational status across multiple metastatic sites is particularly important since the effectiveness of some therapeutic approaches relies on this occurring. mRNA analyses, by contrast, identified a small number of genes in the primary tumor that differed from one metastatic tumor. This divergence implies that a single biopsy analysis for mRNA expression has the potential to be misleading.

Questions for Future Research
Q: Because a small cohort of genes in the girl’s primary tumor were different from genes in portions of the metastatic tumor, would genomic and proteomic analyses provide additional details about this genetic evolution?
Q: How do site-specific differences in mRNA expression affect decisions about which therapies to provide and in which order?

Source: “Histological and Molecular Analysis of a Progressive Diffuse Intrinsic Pontine Glioma and Synchronous Metastatic Lesions: A Case Report.” J. Nazarian, G.E. Mason, C.Y. Ho, E. Panditharatna, M. Kambhampati, L.G. Vezina, R.J. Packer, and E.I. Hwang. Published by Oncotarget on June 14, 2016.

Training t-cells, essential players in the immune system, to fight a trio of viruses

/in , , , /by

Children's is the only U.S. pediatric hospital that manufactures specialized T-cells from native cord blood

PDF Version

What’s Known
Following treatment, patients with leukemia, lymphoma, and other cancers may receive a transplant in order to restore their body’s natural ability to fight infection and, sometimes, such transplants are a component of leukemia treatment. (Leukemia is the second most common blood cancer, after lymphoma, and its incidence rate has increased by 0.2 percent annually from 2002 to 2011.) A stem cell or cord blood transplant restores the body’s ability to produce infection-fighting white blood cells. After such transplants, however, patients can face heightened risk of developing a life-threatening infection with such viruses as adenovirus, cytomegalovirus, or Epstein-Barr virus.

What’s New
A head-to-head comparison of two strategies to thwart such viral infections shows that both approaches leverage the power of multivirus-specific, donor-derived T-cells (mCTL), which are highly skilled at recognizing foreign invaders. The research team, made up of nine scientists and clinicians affiliated with Children’s National Health System, grew personalized T-cells from peripheral blood (PB) of adult donors who were seropositive for CMV and also coaxed T-cells to grow from naïve cord blood (CB). PB-derived cells have long memories of past battles; naïve CB-derived cells need additional training to acquire such skills. From 35 to 384 days after their stem cell or cord blood transplant, 13 patients were infused with PB mCTL and 12 patients were infused with CB mCTL. Within four weeks, patients experienced up to a 160-fold increase in virus-specific T-cells, which coincided with their response to therapy. Overall response rate was 81 percent.

Questions for Future Research
Q: Could T-cells be personalized to attack other viruses that infect patients post-transplant, such as human parainfluenza virus and BK polyomavirus, providing the potential to target five viruses in a single infusion?
Q: Could the proteins that are used to train T-cells to attack certain viruses also be used to create a personalized approach to tumor suppression?

Source: “A Phase 1 Perspective: Multivirus-Specific T Cells From Both Cord Blood and Bone Marrow Transplant Donors.” Hanley, P., M. D. Keller, M. Martin Manso, C. Martinez, K. Leung, C.R. Cruz, C. Barese, S. McCormack, M. Luo, R.A. Krance, D. Jacobsohn, C. Rooney, H. Heslop, E.J. Shpall, and C. Bollard. Presented during the International Society for Cellular Therapy 2016 Annual Meeting, Singapore. May 26, 2016.
researcher using ice bucket in lab

Spatial and temporal homogeneity of driver mutations in diffuse intrinsic pontine glioma

/in , , , , /by

PDF Version

What’s Known
Needle biopsies help to guide diagnosis and targeted therapies for diffuse intrinsic pontine gliomas (DIPGs), which make up 10 percent to 15 percent of all pediatric brain tumors but carry a median survival of 9 to 12 months. This dismal survival rate compares with a 70 percent chance of children surviving other central nervous system tumors five years post diagnosis. In DIPG, tumors appear in the pons, an area of the brain that houses cranial nerve nuclei. Surgical options are limited. Spatial and temporal tumor heterogeneity is a major obstacle to accurate diagnosis and successful targeted therapy.

What’s New
The team sought to better define DIPG heterogeneity. They analyzed 134 specimens from nine patients and found that H3K27M mutations were ubiquitous in all 41 samples with oncogenic content, and always were associated with at least one partner driver mutation: TP53, PPM1D, ACVR1 or PIK3R1. These H3K27M mutations are the initial oncogenic event in DIPG, writes the research team led by Children’s National Health System. “Driver” mutations, such as H3K27M, are essential to begin and sustain tumor formation. This main driver partnership is maintained throughout the course of the disease, in all cells across the tumor, and as tumors spread throughout the brain. Because homogeneity for main driver mutations persists for the duration of illness, efforts to cure DIPG should be directed at the oncohistone partnership, the authors write. Based on early tumor spread, efforts to cure DIPG should aim for early systemic tumor control, rather focused exclusively on the pons.

Questions for Future Research
Q: If a larger sample size were analyzed, what would it reveal about the true heterogeneity/homogeneity status of DIPGs?
Q: “Accessory” driver mutations are not absolutely essential but do help to further promote and accelerate tumor growth. What is their precise role?

Source: “Spatial and Temporal Homogeneity of Driver Mutations in Diffuse Intrinsic Pontine Glioma.” H. Nikbakht, E. Panditharatna, L.G. Mikael, R. Li, T. Gayden, M. Osmond, C.Y. Ho, M. Kambhampati, E.I. Hwang, D. Faury, A. Siu, S. Papillon-Cavanagh, D. Bechet, K.L. Ligon, B. Ellezam, W.J. Ingram, C. Stinson, A.S. Moore, K.E. Warren, J. Karamchandani, R.J. Packer, N. Jabado, J. Majewski, and J. Nazarian. Published by Nature Communications on April 6, 2016.

The role of NG2 proteoglycan in glioma

/in , , , , , /by

A large number of staffers contribute to the Children's National team effort to unravel the mysteries of DIPG. We photograph a few essential players in Dr. Nazarian's lab.

PDF Version

What’s Known
Neuron glia antigen-2 (NG2) is a protein expressed by many central nervous system cells during development and differentiation. NG2-expressing oligodendrocyte progenitor cells have been identified as the cells of origin in gliomas, tumors that arise from the brain’s gluey supportive tissue. What’s more, NG2 expression also has been associated with childhood diffuse intrinsic pontine glioma (DIPG) an aggressive tumor that accounts for 10 percent to 20 percent of pediatric central nervous system (CNS) tumors. Radiation can prolong survival by a few months, but children diagnosed with DIPG typically survive less than one year.

What’s New
Researchers are searching for appropriate targets and effective drugs that offer some chance of benefit. A team of Children’s National Health System researchers investigated whether NG2 – which plays a critical role in proliferation and development of new blood vessels and promotes tumor infiltration – could be a potential target for cancer treatment. Of the various options, antibody-mediated mechanisms of targeting NG2 are feasible, but the size of antibodies limits their ability to cross the blood-brain barrier. “Due to its role in maintaining a pluripotent pool of tumor cells, and its role in tumor migration and infiltration, NG2 provides multiple avenues for developing therapeutics,” the research team concludes. “Moreover, the large extracellular domain of NG2 provides an excellent antigen repertoire for immunotherapeutic interventions. As such, further research is warranted to define the role and expression regulation of NG2 in CNS cancers.”

Questions for Future Research

Q: Because healthy oligodendrocyte progenitor cells are important for the child’s developing brain, how could further characterization of NG2 isoforms help prevent drugs from damaging those beneficial cells?

Q: Could NG2-binding peptides cross the blood-brain barrier to deliver anti-cancer therapies precisely to tumor sites?

Source: “The Role of NG2 Proteoglycan in Glioma.” S. Yadavilli, E.I. Hwang, R. J. Packer, and J. Nazarian. Published by Translational Oncology on February 2016.

Clinicopathology of diffuse intrinsic pontine glioma and its redefined genomic and epigenomic landscape

/in , , , , , /by

Dr. Nazarian's lab

PDF Version

What’s Known
Fewer than 150 U.S. children per year are diagnosed with diffuse intrinsic pontine glioma (DIPG), one of the most lethal pediatric central nervous system cancers. Despite an increasing number of experimental therapies tested via clinical trials, more than 95 percent of these children die within two years of diagnosis. Molecular studies have yielded additional insight about DIPG, including that mutations in histone-encoding genes are associated with 70 percent of cases. Understanding mutations that drive tumors and the genomic landscape can help to guide development of targeted therapies.

What’s New: Frequently found genetic alterations prevalent in DIPGs

dipg-gene-mutations-and-biological-consequences

Source: “Clinicopathology of Diffuse Intrinsic Pontine Glioma and Its Redefined Genomic and Epigenomic Landscape.” E. Panditharatna, K. Yaeger, L.B. Kilburn, R.J. Packer, and J. Nazarian. Published by Cancer Genetics on May 1, 2015.