Publications by authors named "Duane A Mitchell"

The success of cancer immunotherapies is predicated on the targeting of highly expressed neoepitopes, which preferentially favours malignancies with high mutational burden. Here we show that early responses by type-I interferons mediate the success of immune checkpoint inhibitors as well as epitope spreading in poorly immunogenic tumours and that these interferon responses can be enhanced via systemic administration of lipid particles loaded with RNA coding for tumour-unspecific antigens. In mice, the immune responses of tumours sensitive to checkpoint inhibitors were transferable to resistant tumours and resulted in heightened immunity with antigenic spreading that protected the animals from tumour rechallenge.

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Glioblastoma (GBM) displays pronounced intratumoral heterogeneity, posing significant challenges to understanding its biology and developing effective treatments. Using spatial multi-omics, functional assays, and systems-level analysis, we delineate the diverse metabolic and immune architecture of GBM. We identify a lipid-dependent lineage of treatment-resistant persister cells (TRPCs) that engage tumor-associated macrophages (TAMs) in a spatially organized, metabolically specialized crosstalk.

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Tumor-associated macrophages (TAMs) are abundant in the tumor microenvironment (TME) and dampen the immune response, negatively affecting patient survival. Therefore, targeting TAMs could address the limitations of current cancer treatments. However, drug development in this area remains limited.

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The human cytomegalovirus (CMV) antigen pp65 is expressed in high-grade glioma (HGG) and medulloblastoma but not in the adjacent brain. This single-arm phase 1 trial ( NCT03299309 ) assessed the safety and immunogenicity of a peptide vaccine (PEP-CMV) targeting pp65 in individuals (3-35 years old) with recurrent HGG or medulloblastoma. Thirty-six individuals with HGG received PEP-CMV.

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Aims: This study identifies single-nucleotide polymorphisms (SNPs) associated with cellular response to cyclophosphamide (CTX) using phosphoramide mustard (PM), its primary cytotoxic metabolite, and explores the downstream consequences for breast cancer (BC) patients.

Methods: We analyzed 1,978,545 SNPs from EBV-transformed lymphoblastic cell lines (LCLs) derived from 53 unrelated European individuals, in a genome-wide association study using cellular PM sensitivity data. We filtered SNPs associated with PM sensitivity ( < 5 × 10) predicted to overlap with regulatory elements in breast tissue using a chromatin state prediction model.

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Objective: The objective of this study was to develop a murine system for the delivery of laser interstitial thermotherapy (LITT) with probe-based thermometry as a model for human glioblastoma treatment to investigate thermal diffusion in heterogeneous brain tissue.

Methods: First, the tissue heating properties were characterized using a diode-pumped solid-state near-infrared laser in a homogeneous tissue model. The laser was adapted for use with a repurposed stereotactic surgery frame utilizing a micro laser probe and Hamilton syringe.

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Article Synopsis
  • Current treatments for high-risk medulloblastoma are ineffective due to tumor heterogeneity, highlighting the need for personalized immunotherapy approaches.
  • A study analyzed the genetic profiles of 170 medulloblastoma tumors to identify potential tumor rejection antigens that could enhance the effectiveness of immune responses.
  • The results indicated that patients expressed various immunogenic antigens, with higher proportions of tumor-associated antigens compared to neoantigens, particularly noting the presence of cancer-testis and new neurodevelopmental antigens across most molecular subgroups.
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There are numerous mechanisms by which glioblastoma cells evade immunological detection, underscoring the need for strategic combinatorial treatments to achieve appreciable therapeutic effects. However, developing combination therapies is difficult due to dose-limiting toxicities, blood-brain-barrier, and suppressive tumor microenvironment. Glioblastoma is notoriously devoid of lymphocytes driven in part by a paucity of lymphocyte trafficking factors necessary to prompt their recruitment and activation.

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Glioblastoma (GBM) poses a significant challenge in clinical oncology due to its aggressive nature, heterogeneity, and resistance to therapies. Cancer stem cells (CSCs) play a critical role in GBM, particularly in treatment resistance and tumor relapse, emphasizing the need to comprehend the mechanisms regulating these cells. Also, their multifaceted contributions to the tumor microenvironment (TME) underline their significance, driven by their unique properties.

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mRNA vaccines have been revolutionary in terms of their rapid development and prevention of SARS-CoV-2 infections during the COVID-19 pandemic, and this technology has considerable potential for application to the treatment of cancer. Compared with traditional cancer vaccines based on proteins or peptides, mRNA vaccines reconcile the needs for both personalization and commercialization in a manner that is unique to each patient but not beholden to their HLA haplotype. A further advantage of mRNA vaccines is the availability of engineering strategies to improve their stability while retaining immunogenicity, enabling the induction of complementary innate and adaptive immune responses.

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Article Synopsis
  • Cancer immunotherapy faces challenges due to poor antigen recognition and an unfriendly tumor microenvironment (TME).
  • Researchers developed "onion-like" multi-lamellar RNA lipid particle aggregates (LPAs) that enhance the delivery and effectiveness of tumor mRNA antigens by activating specific immune responses in the body.
  • In studies with dogs and humans, RNA-LPAs showed promising results, improving survival rates and triggering strong immune reactions against tumors, suggesting they could be a breakthrough method for cancer treatment.
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Article Synopsis
  • Glioblastoma (GBM) is a tough cancer to treat due to its aggressive nature and resistance to therapies, making understanding cancer stem cells (CSCs) crucial for combating it.
  • This study focused on characterizing slow-cycling glioblastoma stem cells (SCCs) in a mouse model (KR158) to see how similar they are to human SCCs.
  • Findings revealed that KR158 mouse SCCs have key characteristics, including the ability to self-renew and resist chemotherapy, validating this model for further research into GSCs and their role in GBM progression and treatment strategies.
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The COVID-19 pandemic has caused about seven million deaths worldwide. Preventative vaccines have been developed including Spike gp mRNA-based vaccines that provide protection to immunocompetent patients. However, patients with primary immunodeficiencies, patients with cancer, or hematopoietic stem cell transplant recipients are not able to mount robust immune responses against current vaccine approaches.

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Background: Despite advancements in the successful use of immunotherapy in treating a variety of solid tumors, applications in treating brain tumors have lagged considerably. This is due, at least in part, to the lack of well-characterized antigens expressed within brain tumors that can mediate tumor rejection; the low mutational burden of these tumors that limits the abundance of targetable neoantigens; and the immunologically "cold" tumor microenvironment that hampers the generation of sustained and productive immunologic responses. The field of mRNA-based therapeutics has experienced a boon following the universal approval of COVID-19 mRNA vaccines.

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Background: Glioblastoma is the most common malignant brain tumor, and thus it is important to be able to identify patients with this diagnosis for population studies. However, this can be challenging as diagnostic codes are nonspecific. The aim of this study was to create a computable phenotype (CP) for glioblastoma multiforme (GBM) from structured and unstructured data to identify patients with this condition in a large electronic health record (EHR).

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There are enormous enthusiasm and concerns in applying large language models (LLMs) to healthcare. Yet current assumptions are based on general-purpose LLMs such as ChatGPT, which are not developed for medical use. This study develops a generative clinical LLM, GatorTronGPT, using 277 billion words of text including (1) 82 billion words of clinical text from 126 clinical departments and approximately 2 million patients at the University of Florida Health and (2) 195 billion words of diverse general English text.

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Background: Patients with primary brain tumors (pPBTs) often exhibit heightened distress. This study assesses how symptoms of anxiety and depression change over time in pPBTs and identifies factors that may predict patients' symptom trajectories.

Methods: Ninety-nine adult pPBTs completed psychosocial assessments at neuro-oncology appointments over 6-18 months.

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Chimeric antigen receptor (CAR) T cell therapy has demonstrated remarkable success as an immunotherapy for hematological malignancies, and its potential for treating solid tumors is an active area of research. However, limited trafficking and mobility of T cells within the tumor microenvironment (TME) present challenges for CAR T cell therapy in solid tumors. To gain a better understanding of CAR T cell function in solid tumors, we subjected CD70-specific CAR T cells to a challenge by evaluating their immune trafficking and infiltration through a confined 3D microchannel network in a bio-conjugated liquid-like solid (LLS) medium.

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Introduction: The Florida-California Cancer Research, Education, and Engagement (CaRE) Health Equity Center is a triad partnership committed to increasing institutional capacity for cancer disparity research, the diversity of the cancer workforce, and community empowerment. This article provides an overview of the structure, process innovations, and initial outcomes from the first 4 years of the CaRE triad partnership.

Methods: CaRE serves diverse populations in Florida and California using a "molecule to the community and back" model.

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Messenger RNA (mRNA) has emerged as a remarkable tool for COVID-19 prevention but its use for induction of therapeutic cancer immunotherapy remains limited by poor antigenicity and a regulatory tumor microenvironment (TME). Herein, we develop a facile approach for substantially enhancing immunogenicity of tumor-derived mRNA in lipid-particle (LP) delivery systems. By using mRNA as a molecular bridge with ultrapure liposomes and foregoing helper lipids, we promote the formation of 'onion-like' multi-lamellar RNA-LP aggregates (LPA).

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To prospectively determine whether brain tumors will respond to immune checkpoint inhibitors (ICIs), we developed a novel mRNA vaccine as a viral mimic to elucidate cytokine release from brain cancer cells in vitro. Our results indicate that cytokine signatures following mRNA challenge differ substantially from ICI responsive versus non-responsive murine tumors. These findings allow for creation of a diagnostic assay to quickly assess brain tumor immunogenicity, allowing for informed treatment with ICI or lack thereof in poorly immunogenic settings.

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Cancer immunotherapy offers lifesaving treatments for cancers, but the lack of reliable preclinical models that could enable the mechanistic studies of tumor-immune interactions hampers the identification of new therapeutic strategies. We hypothesized 3D confined microchannels, formed by interstitial space between bio-conjugated liquid-like solids (LLS), enable CAR T dynamic locomotion within an immunosuppressive TME to carry out anti-tumor function. Murine CD70-specific CAR T cells cocultured with the CD70-expressing glioblastoma and osteosarcoma demonstrated efficient trafficking, infiltration, and killing of cancer cells.

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Purpose: An ongoing challenge in cancer is the management of primary and metastatic brain malignancies. This is partly due to restrictions of the blood-brain barrier and their unique microenvironment. These challenges are most evident in cancers such as lymphoma and melanoma, which are typically responsive to treatment in systemic locations but resistant when established in the brain.

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Objectives: Iron oxide nanoparticles have been used to track the accumulation of chimeric antigen receptor (CAR) T cells with magnetic resonance imaging (MRI). However, the only nanoparticle available for clinical applications to date, ferumoxytol, has caused rare but severe anaphylactic reactions. MegaPro nanoparticles (MegaPro-NPs) provide an improved safety profile.

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