Disrupting the CD47-SIRPα anti-phagocytic axis by a humanized anti-CD47 antibody is an efficacious treatment for malignant pediatric brain tumors

Morbidity and mortality associated with pediatric malignant primary brain tumors remain high in the absence of effective therapies. Macrophage-mediated phagocytosis of tumor cells via blockade of the anti-phagocytic CD47-SIRPα interaction using anti-CD47 antibodies has shown promise in preclinical xenografts of various human malignancies. We demonstrate the effect of a humanized anti-CD47 antibody, Hu5F9-G4, on five aggressive and etiologically distinct pediatric brain tumors: group 3 medulloblastoma (primary and metastatic), atypical teratoid rhabdoid tumor, primitive neuroectodermal tumor, pediatric glioblastoma, and diffuse intrinsic pontine glioma. Hu5F9-G4 demonstrated therapeutic efficacy in vitro and in vivo in patient-derived orthotopic xenograft models. Intraventricular administration of Hu5F9-G4 further enhanced its activity against disseminated medulloblastoma leptomeningeal disease. Notably, Hu5F9-G4 showed minimal activity against normal human neural cells in vitro and in vivo, a phenomenon reiterated in an immunocompetent allograft glioma model. Thus, Hu5F9-G4 is a potentially safe and effective therapeutic agent for managing multiple pediatric central nervous system malignancies

Publisher Correction: Notch1 regulates the initiation of metastasis and self-renewal of Group 3 medulloblastoma.

The original version of this Article omitted Suzana A. Kahn, Siddhartha S. Mitra & Samuel H. Cheshier as jointly supervising authors. This has now been corrected in both the PDF and HTML versions of the Article

Developmental phosphoproteomics identifies the kinase CK2 as a driver of Hedgehog signaling and a therapeutic target in medulloblastoma

A major limitation of targeted cancer therapy is the rapid emergence of drug resistance, which often arises through mutations at or downstream of the drug target or through intrinsic resistance of subpopulations of tumor cells. Medulloblastoma (MB), the most common pediatric brain tumor, is no exception, and MBs that are driven by sonic hedgehog (SHH) signaling are particularly aggressive and drug-resistant. To find new drug targets and therapeutics for MB that may be less susceptible to common resistance mechanisms, we used a developmental phosphoproteomics approach in murine granule neuron precursors (GNPs), the developmental cell of origin of MB. The protein kinase CK2 emerged as a driver of hundreds of phosphorylation events during the proliferative, MB-like stage of GNP growth, including the phosphorylation of three of the eight proteins commonly amplified in MB. CK2 was critical to the stabilization and activity of the transcription factor GLI2, a late downstream effector in SHH signaling. CK2 inhibitors decreased the viability of primary SHH-type MB patient cells in culture and blocked the growth of murine MB tumors that were resistant to currently available Hh inhibitors, thereby extending the survival of tumor-bearing mice. Because of structural interactions, one CK2 inhibitor (CX-4945) inhibited both wild-type and mutant CK2, indicating that this drug may avoid at least one common mode of acquired resistance. These findings suggest that CK2 inhibitors may be effective for treating patients with MB and show how phosphoproteomics may be used to gain insight into developmental biology and pathology

Epigenetic targeting of Hedgehog pathway transcriptional output through BET bromodomain inhibition

Hedgehog signaling drives oncogenesis in several cancers and strategies targeting this pathway have been developed, most notably through inhibition of Smoothened. However, resistance to Smoothened inhibitors occurs via genetic changes of Smoothened or other downstream Hedgehog components. Here, we overcome these resistance mechanisms by modulating GLI transcription via inhibition of BET bromodomain proteins. We show the BET bromodomain protein, BRD4, regulates GLI transcription downstream of SMO and SUFU and chromatin immunoprecipitation studies reveal BRD4 directly occupies GLI1 and GLI2 promoters, with a substantial decrease in engagement of these sites upon treatment with JQ1, a small molecule inhibitor targeting BRD4. Globally, genes associated with medulloblastoma-specific GLI1 binding sites are downregulated in response to JQ1 treatment, supporting direct regulation of GLI activity by BRD4. Notably, patient- and GEMM-derived Hedgehog-driven tumors (basal cell carcinoma, medulloblastoma and atypical teratoid/rhabdoid tumor) respond to JQ1 even when harboring genetic lesions rendering them resistant to Smoothened antagonists

Gpr124 is essential for blood-brain barrier integrity in central nervous system disease

Although blood-brain barrier (BBB) compromise is central to the etiology of diverse central nervous system (CNS) disorders, endothelial receptor proteins that control BBB function are poorly defined. The endothelial G-protein-coupled receptor (GPCR) Gpr124 has been reported to be required for normal forebrain angiogenesis and BBB function in mouse embryos, but the role of this receptor in adult animals is unknown. Here Gpr124 conditional knockout (CKO) in the endothelia of adult mice did not affect homeostatic BBB integrity, but resulted in BBB disruption and microvascular hemorrhage in mouse models of both ischemic stroke and glioblastoma, accompanied by reduced cerebrovascular canonical Wnt-β-catenin signaling. Constitutive activation of Wnt-β-catenin signaling fully corrected the BBB disruption and hemorrhage defects of Gpr124-CKO mice, with rescue of the endothelial gene tight junction, pericyte coverage and extracellular-matrix deficits. We thus identify Gpr124 as an endothelial GPCR specifically required for endothelial Wnt signaling and BBB integrity under pathological conditions in adult mice. This finding implicates Gpr124 as a potential therapeutic target for human CNS disorders characterized by BBB disruption

Mechanism of Response and Resistance to CAR T Cell Therapies

While CAR T cell therapy has demonstrated remarkable success in treating leukemia, lymphoma, and multiple myeloma, its effectiveness in treating solid tumors, such as glioblastoma (GBM), remains limited. It is imperative to comprehend the mechanisms that hinder the efficacy of CAR T cell therapies and to devise strategies to counteract tumor resistance. In this study, we hypothesized that disruptions in the cell-intrinsic interferon (IFN) signaling pathway contribute to the establishment of an immunosuppressive tumor microenvironment in solid tumors, ultimately rendering solid tumor cells resistant to CAR T cell-mediated elimination. To investigate this, we established syngeneic models of IFN signaling-deficient tumors in the context of murine IL-13Ra2 targeted CAR T cell therapy. Our findings revealed that these models indeed manipulate the tumor microenvironment (TME), leading to a resistance to CAR T cell therapy. Notably, we observed variations in gene expression related to IFN signaling components and cytokines between IFN signaling-deficient tumor cells and wild type (WT) tumor cells following CAR T cell treatment. Moreover, employing techniques such as single-cell RNA sequencing and mass cytometry analysis, we scrutinized the immune cell infiltrates within tumors lacking IFN signaling in comparison to WT controls. This in-depth analysis identified key immune-mediated factors contributing to the resistance observed in tumors with disrupted Janus Kinase1 (JAK1/KO) signaling upon CAR T cell therapy. Specifically, CAR T cell-treated IFN signaling-deficient tumors exhibited reduced T-cell transcripts, characterized by a decline in the frequency of CD8-early active and CD8-native like T cells. Conversely, an increase in regulatory and follicular T cells, exhausted endogenous T cells, and even exhausted CAR T cells was observed in treated IFN signaling-deficient tumors when contrasted with treated WT tumors. Furthermore, our analyses underscored the enrichment of genes associated with fibroblasts, neutrophils, and myeloid cells within IFN signaling-deficient tumors in contrast to WT tumors. These findings collectively suggest that the immune suppressive communication within the IFN signaling-deficient tumor microenvironment could arise due to the differential enhancement of receptor-ligand interactions, such as SPP1+ tumor-associated macrophages (TAMs) and CD44+ cancer-associated fibroblasts (CAFs), along with interactions involving integrins on other cell lineages. To address the resistance observed in IFN-deficient tumors, we devised strategies aimed at enhancing the efficacy of CAR T cell therapy by promoting the recruitment of activated immune cells and reshaping the tumor microenvironment. We next conducted an analysis of immune signatures in 32 GBM patients who exhibited progressive disease following CAR T cell treatment, comparing them with patients who displayed relatively stable disease or showed signs of improvement. Our investigations revealed the presence of fibroblasts and SPP1+ APOE+ C1QA+ C1QC+ myeloid cells within the GBM signatures, which are associated with immune suppression and resistance to therapy. Notably, patients with GBM who displayed a relatively stable treatment response and enhanced T cell recruitment demonstrated distinct expression patterns of interferon regulatory factors (IRFs) compared to patients with less favorable treatment responses. These findings offer insights into the intricate interplay between tumor-intrinsic driver mutations, the composition of the tumor microenvironment, and the responsiveness of solid tumors to CAR T cell therapy. Importantly, our study provides potential avenues for addressing resistance in tumors that do not respond to interferon-based therapies.</p

Gastrointestinal Tuberculosis with Cecum Involvement in a 33-Year-Old Woman

Abdominal tuberculosis is one of the most prevalent forms ofextra-pulmonary tuberculosis. Various regions of gastrointestinaltract including cecum, terminal ileum, peritoneum, lymphaticsystem, and solid viscera can be affected by tuberculosis.Here we report a 33-year-old woman presented with fever,chills, and a history of abdominal discomfort. Lymphadenopathywas detected on physical examination. Contrast computedtomography of chest and abdomen showed patchy densitiesand thickening of the ileocecal wall respectively. Histologicalstudies of the biopsy samples documented the existence oftuberculosis

GD2-Targeted Immunotherapy and Potential Value of Circulating microRNAs in Neuroblastoma

Neuroblastoma (NB) with various clinical presentation is a known childhood malignancy. Despite significant progress in treatment of NB afflicted patients, high risk disease is usually associated with poor outcome, resulting in long-term survival of less that 50%. Known as a disease most commonly originated form the nerve roots, the variants involved in NB imitation and progression remain to be elucidated. The outcome of low to intermediate risk disease is favorable whereas the high risk NB disease with dismal prognosis, positing the necessity of novel approaches for early detection and prognostication of advanced disease. Tailored immunotherapy approaches have shown significant improvement in high-risk NB patients. It has found a link between Gangliosides and progression of NB. The vast majority of neuroblastoma tumors express elevated levels of GD2, opening new insight into using anti-GD2 drugs as potential treatments for NBs. Implication of anti-GD2 monoclonal antibodies for treatment of high risk NBs triggers further investigation to unearth novel biomarkers as prognostic and response biomarker to guide additional multimodal tailored treatment approaches. A growing body of evidence supports the usefulness of miRNAs to evaluate high risk NBs response to anti-GD2 drugs and further prevent drug-related toxicities in refractory or recurrent NBs. miRNAs and circulating proteins in body fluids (plasma, and serum) present as potential biomarkers in early detection of NBs. Here, we summarize various biomarkers involved in diagnosis, prognosis and response to treatment in patients with NB. We further attempted to overview prognostic biomarkers in response to treatment with anti-GD2 drugs