Fahmin Basher, MD, PhD
Project Title: Persistence and Pathological Functions of Circulating BCR-activated B cells in Chronic GVHD
Mentor: Stefanie Sarantopoulos, MD, PhD
Training Track: III, Hematopoiesis and Cellular Therapy
Award Years: 2022-2024
Project Description: Chronic graft-versus-host disease (cGVHD) remains a major cause of morbidity and mortality after allogeneic hematopoietic stem cell transplantation (HCT). While T cells play a major role in mediating the onset of acute and chronic GVHD, a role for B cells in cGVHD has been substantiated. Mouse studies showed that immunoglobulin (IgG)-producing B cells are required for cGVHD. cGVHD patients have allo- and auto-antibodies and antigen-experienced CD27+ B cells from patients with cGVHD constitutively produce IgG. Our group established a role for pathogenic B-cell receptor (BCR) signaling in cGVHD. We found that cGVHD patient B cells exhibited increased ex vivo BCR-responsiveness to surrogate antigen. We showed that increased BCR activation is, in part, due to increased activation and maintenance of the proximal BCR signaling protein molecule, SYK. Clinical trials are currently investigating safety and efficacy of the SYK inhibitor fostamatinib. In addition to SYK, our lab has identified other intrinsic molecular aberrations via single-cell RNA sequencing analyses of HCT patient B cells. Differential gene (DE) analyses identified genes important in maturation, activation, and memory formation that were heterogeneously expressed in patient B cells with active cGVHD compared to those without active disease, healthy controls, and patients with chronic viral infection. These analyses suggest that in the presence of allo-antigen and BAFF in cGVHD, intrinsic factors, including nucleic-acid receptor triggered activation pathways and transcription factors that leads to premature bypass of checkpoints necessary for maturation and production of typical memory B cells.
Based on preliminary results, we plan to elucidate the role of specific genes identified in our analysis of atypical BCR-activate B cells from cGVHD patients. We plan to focus on intracellular DNA-sensing receptors previously described as tumor suppressor genes that are also expressed on memory B cells. While DNA sensors have been implicated in the pathogenesis of autoimmunity through inflammasome production in monocytes, how these receptors operate in B cells and their role in BCR-activated B cell function has not yet been determined. We also plan to identify the role of specific transcription factors implicated in B cell differentiation and Syk transcription in pathogenic alloantibody production using preclinical mouse models already and ex vivo human B cell assays established in the lab.
How BCR-activated B cells arise and are perpetuated under constant exposure to alloantigens will impact diseases beyond cGVHD. Thus, our work has implications for immune-mediated pathologic destruction of platelets and red blood cells as well as hyperalloimmunization.
Hutton Chapman, MD
Project Title: Feasibility and Safety of the use of High-dose Methotrexate in the treatment of Pediatric Burkitt Lymphoma in Tanzania
Mentor: Kristin Schroeder, MD
Training Track: Training Track: III, Hematopoiesis & Cellular Therapy
Award Years: 2022-2024
Project Description: Despite the phenomenal advances in treatment of pediatric cancer in the U.S. and other high resource settings, the outcomes of the same diseases remain extraordinarily poor in low resource settings. Pediatric Burkitt lymphoma is one notable example of this disparity. Burkitt lymphoma represents the most common non-Hodgkin lymphoma, and, in sub-Saharan Africa (SSA), it is likely the most common pediatric cancer, with some estimating that new cases comprise >50% of all pediatric cancer diagnosis. Despite many advances in the treatment of Burkitt lymphoma over the last several decades, the treatments and outcomes in SSA lag significantly. For comparison, intermediate risk children treated with COPADM in high resource settings achieve a >90% 3-year EFS and the inclusion of rituximab (COPADM-R) has improved event survival rates of children with even high-risk disease to >90%. By contrast, current standard of care offered in many countries in SSA result in survival rates of 40%-60% for stage I/II disease, and <30% for stage III/IV disease. While there are likely numerous root causes that contribute to these poor outcomes (e.g. financial, food security, etc.), one notable difference is the difference in chemotherapy that is used to treat pediatric Burkitt lymphoma in SSA.
For our study population of interest, children with a new diagnosis of Burkitt lymphoma in Mwanza, Tanzania, the current standard of care used involves six cycles of cyclophosphamide, vincristine, and low-dose methotrexate (COM). One of the most notable difference in this chemotherapy with the modern regimen, is the incorporation of high-dose methotrexate (HD-MTX). Even early trials incorporating HD-MTX resulted in a near doubling of the EFS (43% to 81%). Therefore, the incorporation of HD-MTX into the regimen used to treat pediatric Burkitt lymphoma in our study population is theorized to have significant impact on survival. However, it is well known that the administration of HD-MTX has a high risk of toxicity, including severe mucositis, AKI, myelosuppression, and subsequent infectious complications. While the safe administration of HD-MTX is well established in high resource settings, potential toxicity and reduced supportive care infrastructure have limited its implementation in low resource settings. Therefore, we aim to determine the feasibility and safety of the implementation of HD-MTX in our study cohort.
Joyce Hwang, MD, PhD
Project Title: Antibody-based modulation of anti-tumor immunity
Mentor: Barton Haynes (primary), Mihai Azoitei (secondary)
Training Track: IV, MOLECULAR BIOLOGY, SIGNALING & GENETICS
Award Years: 2022-2024
Project Description: NK cells have unique physiologic properties that support an anti-tumor response. NKG2A is an inhibitory receptor that recognizes the non-classical HLA class I molecule HLA-E in complex with a subset of host peptides called VL9. When HLA-E/VL9 binds NKG2A, NK cell killing and cytokine production is suppressed.
In prior work, the Haynes lab isolated anti-HLA-E/VL9 antibodies from mouse and human sera that had not undergone deliberate immunization. These antibodies promote killing by NK cells in cell culture. HLA-E is expressed at low levels in normal cells but at high levels in select tumors, lending added specificity to targeting of this checkpoint. The goal of the proposed study is to evaluate the role of the NKG2A/HLA-E/VL9 axis in tumor killing in vivo and optimize antibody-based targeting of this checkpoint. More broadly, we are interested in elucidating the role of endogenous antibodies in modulating anti-tumor responses.
Andrew Peseski, DO
Project Title: Venous thrombosis and cancer; a retrospective study investigating complications at Duke University Medical
Mentor: Thomas Ortel, MD, PhD
Training Track: Training Track: II, Hemostasis and Thrombosis
Award Years: 2022-2024
Project Description: Cancer associated thrombosis is a major cause for both morbidity and mortality. It is the second leading cause of death in cancer patients, behind progression of disease. Active cancer is responsible for up to 20% of all cases of venous thromboembolism (VTE). Historically, treatment for VTE in patients with cancer was warfarin until the CLOT trial was published in 2003. This landmark study demonstrated reduction in recurrence of VTE with low molecular weight heparin (LMWH) when compared to warfarin. More recently, several trials in the last 5 years (Hokusai-VTE, SELECT-D, ADAM VTE, and Caravaggio) have shown non-inferiority with direct oral anticoagulants (DOACs) compared to LMWH when preventing recurrent VTE in patients with active malignancy. However, the additional treatment options to prevent thrombotic reoccurrence come at the expense of increased risk of major and minor bleeds, especially in the gastrointestinal cancer subgroups. Although these landmarks trials outlined new treatment opportunities, they either excluded (Caravaggio) or had very few patients with primary brain tumors or metastatic disease to the brain. It is imperative to build upon these previous investigations and further evaluate VTE treatment options and their complications in cancer patients, especially in patients with metastatic disease to the brain and primary cerebral malignancies.
In our study, we aim to further evaluate the rates of recurrent thrombotic and hemorrhagic complications in patients with a history of VTE and cancer, especially those with metastatic disease to the brain and primary cerebral malignancies. We plan to expand on previous studies, not only by investigating into such correlation in the patient population at the Duke University Medical System, but also by comparing a larger cohort with further emphasis on when these complications took place during the disease course, additional thrombotic risk factors, and further stratifying on patient personal and disease characteristics.
Michele Sainvil, MD
Project Title: A Prospective Patient-centered Exploration of Barriers and Facilitators to Stool Biospecimen Banking among Minoritized Patients Undergoing Hematopoietic Cell Transplantation (HCT)
Mentor: Anthony Sung, MD; Tamara Somers, PhD
Training Track: Cellular Therapy, Track III
Award Years: 2023-2025
Project Description: Cellular therapies like Hematopoietic Stem Cell Transplantation (HCT) and Chimeric-Antigen Receptor T-cell therapy (CAR-T) are curative for high-risk hematologic malignancies. However, medically underserved patient populations encounter barriers to care, leading to disparities closely linked to social determinants of health. These disparities, including limited access to education, socioeconomic status, and healthcare access, contribute to reduced enrollment in clinical trials and unequal access to life-saving therapies. Notably, health disparities in biobanking enrollment among HCT patients further hinder research representation, impeding advancements in personalized medicine, and leading to poorer outcomes despite comparable HCT acceptance rates. Studies have emphasized the underrepresentation of minoritized participants in biobanks, limiting research diversity. We propose collecting longitudinal stool specimens in a biospecimen repository, from HCT patients at Duke University Cancer Center, generating large-scale data for a comprehensive understanding of microbiome variations. However, to date, the participation of minoritized patients remains lag.
We propose a prospective mixed methods study to identify factors leading to poor stool biospecimen study enrollment in minoritized participants during stem cell transplantation. Understanding the factors influencing poor stool biospecimen enrollment and collection in minoritized participants. By developing a culturally sensitive question guide and conducting interviews, we seek to explore consent rates, variations in participation, and potential interventions to enhance inclusivity in research. Uncovering specific challenges fosters a deeper understanding of barriers to biospecimen and clinical trial research participation, informing targeted interventions to bridge disparities, increase participation, and improve access to personalized medicine for historically minoritized populations undergoing HCT.
Katherine Zhou, MD, PhD
Project Title: Canonical and non-canonical functions of the snoRNA Snord67 in the regulation of alternative splicing and modulation of the immune system
Mentor: Chad Pecot, MD; Christopher Holley, MD, PhD
Training Track: IV, MOLECULAR BIOLOGY, SIGNALING & GENETICS
Award Years: 2023-2025
Project Description: Small nucleolar RNAs (snoRNAs) are small noncoding RNAs that guide post-transcriptional 2′-O-methylation and pseudouridylation of ribosomal RNAs and small nuclear RNAs. In addition to these canonical roles, snoRNAs have non-canonical functions including the modification of messenger RNAs and microRNAs, as well as the regulation of transcription and post-transcriptional processing. Recent work in the Pecot lab has demonstrated that the snoRNA Snord67 promotes aberrant cell proliferation and migration in lymph nodes. Knockout of Snord67 led to widespread changes in alternative splicing, as well as decreased cell proliferation. However, the mechanisms underlying these phenotypes remain unclear. The goal of my research project is to investigate the canonical and non-canonical mechanisms by which Snord67 leads to changes in alternative splicing and changes in cellular phenotype.
