Publications by authors named "Nicolo Riggi"

Article Synopsis
  • The study investigates the role of a master regulator gene in the development of excitatory neurons, specifically focusing on its function in cerebellar granule neuron progenitors (GNPs).
  • Researchers found that dysfunction of this gene in GNPs reduced their proliferation and led to various cerebellar abnormalities, including hypoplasia and imbalances in neuron ratios.
  • The findings suggest that deletion of this gene during early development can cause autism-like behaviors in mice and highlight uncharacterized gene variants associated with autism spectrum disorder in humans.
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EWS fusion oncoproteins underlie several human malignancies including Desmoplastic Small Round Cell Tumor (DSRCT), an aggressive cancer driven by EWS-WT1 fusion proteins. Here we combine chromatin occupancy and 3D profiles to identify EWS-WT1-dependent gene regulation networks and target genes. We show that EWS-WT1 is a powerful chromatin activator controlling an oncogenic gene expression program that characterizes primary tumors.

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The development of targeted therapies offers new hope for patients affected by incurable cancer. However, multiple challenges persist, notably in controlling tumor cell plasticity in patients with refractory and metastatic illness. Neuroblastoma (NB) is an aggressive pediatric malignancy originating from defective differentiation of neural crest-derived progenitors with oncogenic activity due to genetic and epigenetic alterations and remains a clinical challenge for high-risk patients.

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CIC-DUX4-rearranged sarcoma (CDS) is a rare and aggressive soft tissue tumor that occurs most frequently in young adults. The key oncogenic driver of this disease is the expression of the CIC-DUX4 fusion protein as a result of chromosomal rearrangements. CIC-DUX4 displays chromatin binding properties, and is therefore believed to function as an aberrant transcription factor.

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Article Synopsis
  • Amplification of MDM2 on extra chromosomes is a frequent way tumors inactivate the P53 protein, which is crucial for controlling cell growth and preventing cancer.
  • In dedifferentiated liposarcoma, MDM2 overexpression affects gene regulation and cell characteristics through three main regulatory circuits and interacts with other transcription factors.
  • There is significant variability in MDM2 levels within tumor cells, and while most liposarcoma cells respond to MDM2 inhibitors combined with pro-apoptotic drugs, those with high MDM2 levels tend to resist these treatments, leading to poor clinical outcomes.
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Intrinsically disordered regions (IDRs) in DNA-associated proteins are known to influence gene regulation, but their distribution and cooperative functions in genome-wide regulatory programs remain poorly understood. Here we describe DisP-seq (disordered protein precipitation followed by DNA sequencing), an antibody-independent chemical precipitation assay that can simultaneously map endogenous DNA-associated disordered proteins genome-wide through a combination of biotinylated isoxazole precipitation and next-generation sequencing. DisP-seq profiles are composed of thousands of peaks that are associated with diverse chromatin states, are enriched for disordered transcription factors (TFs) and are often arranged in large lineage-specific clusters with high local concentrations of disordered proteins and different combinations of histone modifications linked to regulatory potential.

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Article Synopsis
  • Scientists studied how cells change during early development and wanted to see if similar changes happen in cancer cells, specifically in a type of pediatric cancer called Ewing sarcoma.
  • They found that a protein called EWS-FLI1 creates special connections in the cell’s DNA that help the cancer cells grow.
  • When they took away EWS-FLI1, the DNA connections changed back to a more normal state, which might allow the cells to behave more like healthy stem cells.
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Introduction: Clear cell sarcoma (CCS) is an ultrarare soft tissue sarcoma (STS) with a poor prognosis due to its propensity to metastasize and its low chemosensitivity. The standard treatment of localized CCS consists of wide surgical excision with or without additive radiotherapy. However, unresectable CCS is generally treated with conventional systemic therapies available for treatment of STS despite the weak scientific evidence to support its use.

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Oncogenic fusion proteins generated by chromosomal translocations play major roles in cancer. Among them, fusions between EWSR1 and transcription factors generate oncogenes with powerful chromatin regulatory activities, capable of establishing complex gene expression programs in permissive precursor cells. Here we define the epigenetic and 3D connectivity landscape of Clear Cell Sarcoma, an aggressive cancer driven by the EWSR1-ATF1 fusion gene.

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Recent evidence suggests that numerous similarities exist between the genomic landscapes of both conjunctival and cutaneous melanoma. Since alterations of several components of the MAP kinases, PI3K/mTOR, and cell cycle pathways have been reported in conjunctival melanoma, we decided to assess the sensitivity of conjunctival melanoma to targeted inhibition mostly of kinase inhibitors. A high content drug screening assay based on automated fluorescence microscopy was performed in three conjunctival melanoma cell lines with different genomic backgrounds with 489 kinase inhibitors and 53 other inhibitors.

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Article Synopsis
  • The transcription factors TWIST1/2 are often overexpressed in cancer, and this study focuses on their roles in neuroblastoma (NB), a childhood cancer with varying outcomes.
  • TWIST1 is linked to worse survival rates and increased metastasis in NB, while TWIST2 is associated with better prognosis.
  • By using CRISPR/Cas9 to suppress TWIST1, researchers found reduced tumor growth and a less aggressive tumor structure, suggesting TWIST1 could be a potential target for new NB therapies.
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Malignant tumors commonly display necrosis, which invariably triggers an inflammatory response that supports tumor growth. However, the effect on tumor cells of necrotic debris, or damage-associated molecular patterns (DAMPs) released by dying cells is unknown. Here, we addressed the effect of DAMPs on primary Ewing sarcoma (EwS) cells and cell lines grown in 3D (spheroids) and 2D culture.

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Targeting of the most aggressive tumor cell subpopulations is key for effective management of most solid malignancies. However, the metastable nature of tumor heterogeneity, which allows cells to transition between strong and weak tumorigenic phenotypes, and the lack of reliable markers of tumor-promoting properties hamper identification of the most relevant cells. To overcome these obstacles, we designed a functional microRNA (miR)-based live-cell reporter assay to identify highly tumorigenic cells in xenotransplants of primary Ewing sarcoma (EwS) 3D cultures.

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Aims: Conjunctival and cutaneous melanoma partially share similar clinical and molecular backgrounds. As 5-hydroxymethylcytosine (5-hmC) loss has been demonstrated in cutaneous melanoma, we decided to assess if similar changes were occurring in conjunctival melanoma.

Methods: 5-methylcytosine (5-mC), 5-hmC and TET2 were respectively identified by immunohistochemistry and RNA ISH in 40 conjunctival nevi and 37 conjunctival melanomas.

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Cancer evolution determines molecular and morphologic intratumor heterogeneity and challenges the design of effective treatments. In lung adenocarcinoma, disease progression and prognosis are associated with the appearance of morphologically diverse tumor regions, termed histologic patterns. However, the link between molecular and histologic features remains elusive.

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Article Synopsis
  • Synovial sarcoma (SyS) is an aggressive cancer driven by the SS18-SSX fusion, showing low levels of T cell infiltration, which indicates immune evasion.
  • Researchers used single-cell RNA sequencing to analyze 16,872 cells from human SyS tumors, identifying a key malignant subpopulation linked to poorer clinical outcomes and immune-deprived areas.
  • The study found that the malignant cell state is influenced by the SS18-SSX fusion and can be targeted with a combination of HDAC and CDK4/CDK6 inhibitors, boosting T cell responses and enhancing treatment effectiveness.
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Conjunctival melanoma (CJM) is a rare but potentially lethal and highly-recurrent cancer of the eye. Similar to cutaneous melanoma (CM), it originates from melanocytes. Unlike CM, however, CJM is relatively poorly characterized from a genomic point of view.

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Article Synopsis
  • Synovial sarcoma (SyS) is a type of aggressive cancer caused by a specific genetic mutation that fuses the SS18 gene with one of the SSX genes, leading to abnormal gene regulation.
  • Researchers developed organoid models of SyS and conducted extensive genome profiling to uncover how this cancer alters chromatin structure and influences gene expression.
  • Findings revealed that the SS18-SSX fusion disrupts normal cellular processes by changing the way chromatin is remodeled, making SyS cells reliant on specific regulators, and these changes can be reversed if the SS18-SSX fusion is removed.
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Ewing sarcoma (EwS) is associated with poor prognosis despite current multimodal therapy. Targeting of EWS-FLI1, the fusion protein responsible for its pathogenesis, and its principal downstream targets has not yet produced satisfactory therapeutic options, fueling the search for alternative approaches. Here, we show that the oncofetal RNA-binding protein LIN28B regulates the stability of EWS-FLI1 mRNA in ~10% of EwSs.

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Purpose: Endosialin/tumor endothelial marker-1 (TEM1) is an attractive theranostic target expressed by the microenvironment of a wide range of tumors, as well as by sarcoma and neuroblastoma cells. We report on the radiolabeling and preclinical evaluation of the scFv78-Fc, a fully human TEM1-targeting antibody fragment cross-reactive with mouse TEM1.

Procedures: The scFv78-Fc was conjugated with the chelator p-SCN-Bn-CHX-A"-DTPA, followed by labeling with indium-111.

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