Project description:GD2 is a disialoganglioside that is highly expressed on the surface of neuroblastoma cells. Immunotherapy with anti-GD2 antibodies has revolutionized the treatment of children with high-risk neuroblastoma, but nearly half of patients relapse and little is known about mechanisms of resistance to anti-GD2. Neuroblastomas harbor intrinsic transcriptional plasticity by co-opting divergent lineage-specific developmental programs between adrenergic and mesenchymal cell states. We found that reduced GD2 expression was significantly correlated with the adrenergic cell state in neuroblastoma and that an Adrenergic-to-Mesenchymal Transition (AMT) conferred downregulation of GD2 and resistance to anti-GD2 antibody. Induced reprogramming of adrenergic cells with the master AMT regulator PRRX1 was sufficient to promote transcriptional rewiring in isogenic models and downregulate GD2 expression. Mechanistically, low-GD2 expressing cell lines demonstrate significantly reduced expression of the ganglioside synthesis enzyme ST8SIA1 (GD3 synthase), resulting in a bottlenecking of GD2 synthesis. Primary neuroblastoma tumors enriched for mesenchymal features show demonstrably lower GD3 synthase expression as compared to adrenergic tumors. Pharmacologic inhibition of EZH2 resulted in epigenetic rewiring of mesenchymal neuroblastoma cells and re-expression of ST8SIA1, restoring surface expression of GD2 and sensitivity to an anti-GD2 antibody. These data identify developmental lineage as a key determinant of sensitivity to anti-GD2 based immunotherapies and credential EZH2 inhibitors for clinical testing in combination with anti-GD2 antibody to enhance outcomes for children with neuroblastoma.
Project description:GD2 is a disialoganglioside that is highly expressed on the surface of neuroblastoma cells. Immunotherapy with anti-GD2 antibodies has revolutionized the treatment of children with high-risk neuroblastoma, but nearly half of patients relapse and little is known about mechanisms of resistance to anti-GD2. Neuroblastomas harbor intrinsic transcriptional plasticity by co-opting divergent lineage-specific developmental programs between adrenergic and mesenchymal cell states. We found that reduced GD2 expression was significantly correlated with the adrenergic cell state in neuroblastoma and that an Adrenergic-to-Mesenchymal Transition (AMT) conferred downregulation of GD2 and resistance to anti-GD2 antibody. Induced reprogramming of adrenergic cells with the master AMT regulator PRRX1 was sufficient to promote transcriptional rewiring in isogenic models and downregulate GD2 expression. Mechanistically, low-GD2 expressing cell lines demonstrate significantly reduced expression of the ganglioside synthesis enzyme ST8SIA1 (GD3 synthase), resulting in a bottlenecking of GD2 synthesis. Primary neuroblastoma tumors enriched for mesenchymal features show demonstrably lower GD3 synthase expression as compared to adrenergic tumors. Pharmacologic inhibition of EZH2 resulted in epigenetic rewiring of mesenchymal neuroblastoma cells and re-expression of ST8SIA1, restoring surface expression of GD2 and sensitivity to an anti-GD2 antibody. These data identify developmental lineage as a key determinant of sensitivity to anti-GD2 based immunotherapies and credential EZH2 inhibitors for clinical testing in combination with anti-GD2 antibody to enhance outcomes for children with neuroblastoma.
Project description:GD2 is a disialoganglioside that is highly expressed on the surface of neuroblastoma cells. Immunotherapy with anti-GD2 antibodies has revolutionized the treatment of children with high-risk neuroblastoma, but nearly half of patients relapse and little is known about mechanisms of resistance to anti-GD2. Neuroblastomas harbor intrinsic transcriptional plasticity by co-opting divergent lineage-specific developmental programs between adrenergic and mesenchymal cell states. We found that reduced GD2 expression was significantly correlated with the adrenergic cell state in neuroblastoma and that an Adrenergic-to-Mesenchymal Transition (AMT) conferred downregulation of GD2 and resistance to anti-GD2 antibody. Induced reprogramming of adrenergic cells with the master AMT regulator PRRX1 was sufficient to promote transcriptional rewiring in isogenic models and downregulate GD2 expression. Mechanistically, low-GD2 expressing cell lines demonstrate significantly reduced expression of the ganglioside synthesis enzyme ST8SIA1 (GD3 synthase), resulting in a bottlenecking of GD2 synthesis. Primary neuroblastoma tumors enriched for mesenchymal features show demonstrably lower GD3 synthase expression as compared to adrenergic tumors. Pharmacologic inhibition of EZH2 resulted in epigenetic rewiring of mesenchymal neuroblastoma cells and re-expression of ST8SIA1, restoring surface expression of GD2 and sensitivity to an anti-GD2 antibody. These data identify developmental lineage as a key determinant of sensitivity to anti-GD2 based immunotherapies and credential EZH2 inhibitors for clinical testing in combination with anti-GD2 antibody to enhance outcomes for children with neuroblastoma.
Project description:GD2 is a disialoganglioside that is highly expressed on the surface of neuroblastoma cells. Immunotherapy with anti-GD2 antibodies has revolutionized the treatment of children with high-risk neuroblastoma, but nearly half of patients relapse and little is known about mechanisms of resistance to anti-GD2. Neuroblastomas harbor intrinsic transcriptional plasticity by co-opting divergent lineage-specific developmental programs between adrenergic and mesenchymal cell states. We found that reduced GD2 expression was significantly correlated with the adrenergic cell state in neuroblastoma and that an Adrenergic-to-Mesenchymal Transition (AMT) conferred downregulation of GD2 and resistance to anti-GD2 antibody. Induced reprogramming of adrenergic cells with the master AMT regulator PRRX1 was sufficient to promote transcriptional rewiring in isogenic models and downregulate GD2 expression. Mechanistically, low-GD2 expressing cell lines demonstrate significantly reduced expression of the ganglioside synthesis enzyme ST8SIA1 (GD3 synthase), resulting in a bottlenecking of GD2 synthesis. Primary neuroblastoma tumors enriched for mesenchymal features show demonstrably lower GD3 synthase expression as compared to adrenergic tumors. Pharmacologic inhibition of EZH2 resulted in epigenetic rewiring of mesenchymal neuroblastoma cells and re-expression of ST8SIA1, restoring surface expression of GD2 and sensitivity to an anti-GD2 antibody. These data identify developmental lineage as a key determinant of sensitivity to anti-GD2 based immunotherapies and credential EZH2 inhibitors for clinical testing in combination with anti-GD2 antibody to enhance outcomes for children with neuroblastoma.
Project description:GD2 is a disialoganglioside that is highly expressed on the surface of neuroblastoma cells. Immunotherapy with anti-GD2 antibodies has revolutionized the treatment of children with high-risk neuroblastoma, but nearly half of patients relapse and little is known about mechanisms of resistance to anti-GD2. Neuroblastomas harbor intrinsic transcriptional plasticity by co-opting divergent lineage-specific developmental programs between adrenergic and mesenchymal cell states. We found that reduced GD2 expression was significantly correlated with the adrenergic cell state in neuroblastoma and that an Adrenergic-to-Mesenchymal Transition (AMT) conferred downregulation of GD2 and resistance to anti-GD2 antibody. Induced reprogramming of adrenergic cells with the master AMT regulator PRRX1 was sufficient to promote transcriptional rewiring in isogenic models and downregulate GD2 expression. Mechanistically, low-GD2 expressing cell lines demonstrate significantly reduced expression of the ganglioside synthesis enzyme ST8SIA1 (GD3 synthase), resulting in a bottlenecking of GD2 synthesis. Primary neuroblastoma tumors enriched for mesenchymal features show demonstrably lower GD3 synthase expression as compared to adrenergic tumors. Pharmacologic inhibition of EZH2 resulted in epigenetic rewiring of mesenchymal neuroblastoma cells and re-expression of ST8SIA1, restoring surface expression of GD2 and sensitivity to an anti-GD2 antibody. These data identify developmental lineage as a key determinant of sensitivity to anti-GD2 based immunotherapies and credential EZH2 inhibitors for clinical testing in combination with anti-GD2 antibody to enhance outcomes for children with neuroblastoma.
Project description:To identify genomic alterations contributing to the pathogenesis of high‑risk chronic lymphocytic leukemia (CLL) beyond the well‑established role of TP53 aberrations, we comprehensively analyzed 146 high‑risk CLL cases by single‑nucleotide polymorphism (SNP)‑arrays and targeted next‑generation sequencing including 75 relapsed/refractory and 71 treatment‑naïve high‑risk cases from prospective clinical trials. Increased genomic complexity was a hallmark of relapsed/refractory and treatment‑naïve high‑risk CLL, and was associated with TP53 and ATM dysfunction. In relapsed/refractory cases previously exposed to the selective pressure of chemo(immuno)therapy, gain(8)(q24.21) and del(9)(p21.3) were found particularly enriched. Both of these copy number alterations (CNAs) affected key regulators of cell cycle progression, namely c‑MYC and CDKN2A/B. Gains in 8q24.21 were either focal gains in a c‑MYC enhancer region or larger gains directly affecting the c‑MYC locus, but only the latter type was highly enriched in relapsed/refractory CLL (17%). Loss of CDKN2A/B was found frequently to co‑occur with gain of c‑MYC and in this combination it was likely associated with Richter transformation. In addition to a high frequency of NOTCH1 mutations (23%), we found recurrent genetic alterations in SPEN (4% mutated), RBPJ (8% deleted) and SNW1 (8% deleted), all affecting a protein complex that represses transcription of NOTCH1 target genes. We investigated the functional impact of these alterations on HES1, DTX1 and c‑MYC gene transcription and found de‑repression of these NOTCH1 target genes particularly with SPEN mutations. In summary, we provide new insights into the pathogenesis of high‑risk CLL by defining novel recurrent CNAs and identifying alterations that likely contribute to disease refractoriness.
Project description:Multiple myeloma (MM) is a devastating plasma cell malignancy characterized by the expansion of aberrant monoclonal plasma cells in the bone marrow, leading to severe clinical manifestations and poor prognosis, particularly in relapsed/refractory cases. Identifying novel therapeutic targets is crucial to improve treatment outcomes in these patients. In this study, we investigated the role of protein arginine methyltransferase 1 (PRMT1) in MM pathogenesis and explored its potential as a therapeutic target. We observed that PRMT1, responsible for majority of asymmetric di-methylation in cells, exhibited the highest expression among PRMT family members in MM cell lines and primary MM cells. Importantly, PRMT1 expression was significantly elevated in relapsed/refractory patients compared to newly diagnosed patients. High expression of PRMT1 expression was strongly associated with poor prognosis. We found that genetic or enzymatic inhibition of PRMT1 impaired MM cell growth, induced cell cycle arrest, and triggered cell death. Treatment with MS023, a potent PRMT type I inhibitor, demonstrated a robust inhibitory effect on viability of primary cells isolated from both newly diagnosed and proteasome inhibitor-relapsed/refractory patients in a dose-dependent manner. In vivo studies using a xenograft model revealed that targeting PRMT1 by either CRISPR/Cas9-mediated knockout or MS023 treatment significantly attenuated MM tumor growth and prolonged the survival of tumor-bearing mice. Histological analysis further confirmed increased apoptotic cell death in MS023-treated tumors. Collectively, our findings establish PRMT1 as an indispensable and novel therapeutic vulnerability in MM. The elevated expression of PRMT1 in relapsed/refractory patients underscores its potential as a target for overcoming treatment resistance. Moreover, our results highlight the efficacy of MS023 as a promising therapeutic agent against MM, offering new avenues for therapeutic approaches in relapsed/refractory MM.
Project description:The development of targeted therapies has provided new hope for an increasing number of cancer patients affected by previously incurable diseases. The clinical success of this approach, however, is limited by numerous challenges, including a better control of cell plasticity, particularly in refractory and metastatic patients. Here we addressed this question in Neuroblastoma (NB), an aggressive pediatric malignancy, which remains a clinical challenge for high-risk patients. NB originates from neural crest-derived progenitors through defective differentiation programs combined with oncogenic activity due to genetic and epigenetic alterations. In order to identify critical genes responsible for tumor aggressiveness we performed combined chromatin and transcriptome analyses on matched primary xenografts, spheroids and differentiated adherent cultures, which we derived from metastatic non-MYCN amplified (nMNA) NB patients. Our approach identified the kinase BMX among the most differentially regulated genes between patient-derived xenografts and spheroids versus adherent models. We further found that BMX expression is associated with high tumor stage and poor patient survival in multiple NB transcriptomic datasets and critical to maintain the self-renewal and tumorigenic potential of NB spheroids. Moreover, we uncovered a positive correlation between BMX expression and the mesenchymal tumor cell phenotype, which was previously associated with increased chemo-resistance. Finally, we show that BMX inhibitors can readily reverse this cellular state, increase the sensitivity of NB spheroids toward standard of care chemotherapy, and reduce tumor growth in preclinical NB models. Altogether, our study identifies BMX as a novel promising therapeutic target for high-risk patients with relapsed or refractory nMNA NB tumors.