Preclinical pediatric brain tumor models for immunotherapy: Hurdles and a way forward.

Brain tumors are the most common solid tumor in children and the leading cause of cancer-related deaths. Over the last few years, improvements have been made in the diagnosis and treatment of children with Central Nervous System tumors. Unfortunately, for many patients with high-grade tumors, the overall prognosis remains poor.

Chromatin Profiling of CBFA2T3-GLIS2 AMLs Identifies Key Transcription Factor Dependencies and BRG1 Inhibition as a Novel Therapeutic Strategy.

Oncogenic fusions involving transcription factors are present in the majority of pediatric leukemias; however, the context-specific mechanisms they employ to drive cancer remain poorly understood. CBFA2T3-GLIS2 (C/G) fusions occur in treatment-refractory acute myeloid leukemias and are restricted to young children. To understand how the C/G fusion drives oncogenesis we applied CUT&RUN chromatin profiling to an umbilical cord blood/endothelial cell (EC) co-culture model of C/G AML that recapitulates the biology of this malignancy.

CBFA2T3-GLIS2 model of pediatric acute megakaryoblastic leukemia identifies FOLR1 as a CAR T cell target.

The CBFA2T3-GLIS2 (C/G) fusion is a product of a cryptic translocation primarily seen in infants and early childhood and is associated with dismal outcome. Here, we demonstrate that the expression of the C/G oncogenic fusion protein promotes the transformation of human cord blood hematopoietic stem and progenitor cells (CB HSPCs) in an endothelial cell coculture system that recapitulates the transcriptome, morphology, and immunophenotype of C/G acute myeloid leukemia (AML) and induces highly aggressive leukemia in xenograft models. Interrogating the transcriptome of C/G-CB cells and primary C/G AML identified a library of C/G-fusion-specific genes that are potential targets for therapy.

A Protocol for the Generation of Treatment-naïve Biopsy-derived Diffuse Intrinsic Pontine Glioma and Diffuse Midline Glioma Models.

Diffuse intrinsic pontine glioma (DIPG) is a universally fatal tumor of the brainstem, most commonly affecting young children. Due to its location, surgical resection is not achievable, but consideration of a biopsy has become standard practice at children's hospitals with the appropriate neurosurgical expertise. While the decision to obtain a biopsy should be directed by the presence of atypical radiographic features that call the diagnosis of DIPG into question or the requirement of biopsy tissue for clinical trial enrollment, once this precious tissue is available its use for research should be considered.

Optimal therapeutic targeting by HDAC inhibition in biopsy-derived treatment-naïve diffuse midline glioma models.

Background: Diffuse midline gliomas (DMGs), including diffuse intrinsic pontine gliomas (DIPGs), have a dismal prognosis, with less than 2% surviving 5 years postdiagnosis. The majority of DIPGs and all DMGs harbor mutations altering the epigenetic regulatory histone tail (H3 K27M). Investigations addressing DMG epigenetics have identified a few promising drugs, including the HDAC inhibitor (HDACi) panobinostat.

A modified gene trap approach for improved high-throughput cancer drug discovery.

While advances in laboratory automation has dramatically increased throughout of compound screening efforts, development of robust cell-based assays in relevant disease models remain resource-intensive and time-consuming, presenting a bottleneck to drug discovery campaigns. To address this issue, we present a modified gene trap approach to efficiently generate pathway-specific reporters that result in a robust "on" signal when the pathway of interest is inhibited. In this proof-of-concept study, we used vemurafenib and trametinib to identify traps that specifically detect inhibition of the mitogen-activated protein kinase (MAPK) pathway in a model of BRAFV600E driven human malignant melanoma.

Transposon mutagenesis identifies candidate genes that cooperate with loss of transforming growth factor-beta signaling in mouse intestinal neoplasms.

Colorectal cancer (CRC) results from the accumulation of gene mutations and epigenetic alterations in colon epithelial cells, which promotes CRC formation through deregulating signaling pathways. One of the most commonly deregulated signaling pathways in CRC is the transforming growth factor β (TGF-β) pathway. Importantly, the effects of TGF-β signaling inactivation in CRC are modified by concurrent mutations in the tumor cell, and these concurrent mutations determine the ultimate biological effects of impaired TGF-β signaling in the tumor.

Methylated B3GAT2 and ZNF793 Are Potential Detection Biomarkers for Barrett's Esophagus.

Background: Barrett's esophagus (BE) is a preneoplastic condition in which normal esophageal squamous epithelium (SQ) is replaced by specialized intestinal metaplasia. It is the presumed precursor for esophageal adenocarcinoma (EAC) as well as the strongest risk factor for this cancer. Unfortunately, many patients with BE go undiagnosed under the current BE screening guidelines.

A technology platform to assess multiple cancer agents simultaneously within a patient's tumor.

A fundamental problem in cancer drug development is that antitumor efficacy in preclinical cancer models does not translate faithfully to patient outcomes. Much of early cancer drug discovery is performed under in vitro conditions in cell-based models that poorly represent actual malignancies. To address this inconsistency, we have developed a technology platform called CIVO, which enables simultaneous assessment of up to eight drugs or drug combinations within a single solid tumor in vivo.

Differences in DNA methylation signatures reveal multiple pathways of progression from adenoma to colorectal cancer.

Background & Aims: Genetic and epigenetic alterations contribute to the pathogenesis of colorectal cancer (CRC). There is considerable molecular heterogeneity among colorectal tumors, which appears to arise as polyps progress to cancer. This heterogeneity results in different pathways to tumorigenesis.

NTRK3 is a potential tumor suppressor gene commonly inactivated by epigenetic mechanisms in colorectal cancer.

NTRK3 is a member of the neurotrophin receptor family and regulates cell survival. It appears to be a dependence receptor, and thus has the potential to act as an oncogene or as a tumor suppressor gene. NTRK3 is a receptor for NT-3 and when bound to NT-3 it induces cell survival, but when NT-3 free, it induces apoptosis.

Transforming growth factor-beta signaling promotes hepatocarcinogenesis induced by p53 loss.

Unlabelled: Hepatocellular carcinoma (HCC) results from the accumulation of deregulated tumor suppressor genes and/or oncogenes in hepatocytes. Inactivation of TP53 and inhibition of transforming growth factor-beta (TGF-β) signaling are among the most common molecular events in human liver cancers. Thus, we assessed whether inactivation of TGF-β signaling, by deletion of the TGF-β receptor, type II (Tgfbr2), cooperates with Trp53 loss to drive HCC formation.

TGF-beta inactivation and TGF-alpha overexpression cooperate in an in vivo mouse model to induce hepatocellular carcinoma that recapitulates molecular features of human liver cancer.

Hepatocellular carcinoma (HCC) results from the cumulative effects of deregulated tumor suppressor genes and oncogenes. The tumor suppressor and oncogenes commonly affected include growth factors, receptors and their downstream signaling pathway components. The overexpression of transforming growth factor alpha (TGF-alpha) and the inhibition of TGF-beta signaling are especially common in human liver cancer.

Myosin VI binds to and localises with Dab2, potentially linking receptor-mediated endocytosis and the actin cytoskeleton.

Myosin VI, an actin-based motor protein, and Disabled 2 (Dab2), a molecule involved in endocytosis and cell signalling, have been found to bind together using yeast and mammalian two-hybrid screens. In polarised epithelial cells, myosin VI is known to be associated with apical clathrin-coated vesicles and is believed to move them towards the minus end of actin filaments, away from the plasma membrane and into the cell. Dab2 belongs to a group of signal transduction proteins that bind in vitro to the FXNPXY sequence found in the cytosolic tails of members of the low-density lipoprotein receptor family.

Dual roles for the Dab2 adaptor protein in embryonic development and kidney transport.

The Disabled-2 (Dab2) gene has been proposed to act as a tumor suppressor. Cell culture studies have implicated Dab2 in signal transduction by mitogens, TGFbeta and endocytosis of lipoprotein receptors. To identify in vivo functions of Dab2, targeted mutations were made in the mouse.