Biology subjects

Palumbo, O.

Publications and source records attributed to Palumbo, O..

3 recordsLinked to original sources

bioRxiv2022

miRNome profiling of lung cancer metastases revealed a key role for miRNA-PD-L1 axis in the modulation of chemotherapy response

Locally-advanced non-small-cell lung cancer (NSCLC) is frequent at diagnosis and requires multimodal treatment approaches. Neoadjuvant chemotherapy (NACT) followed by surgery is the treatment of choice for operable locally-advanced NSCLC (Stage IIIA). However, the majority of patients are NACT-resistant and shows persistent lymph nodal metastases (LNmets) and an adverse outcome. Therefore, the identification of mechanisms and biomarkers of NACT resistance is paramount for ameliorating prognosis of patients with Stage IIIA NSCLC. Here, we investigated the miRNome and transcriptome of chemo naive LNmets collected from patients with Stage IIIA NSCLC (N=64). We found that a microRNA signature accurately predicts NACT response. Mechanistically, we discovered a miR-455-5p/PD-L1 regulatory axis which drives chemotherapy resistance, hallmarks metastases with active IFN-{gamma} response pathway (an inducer of PD-L1 expression), and impacts T cells viability and relative abundances in tumor-microenviroment (TME). Our data provides new biomarkers to predict NACT response and adds molecular insights relevant for improving the management of patients with locally-advanced NSCLC.

cancer biology↗

bioRxiv2022

Extracellular vesicle microRNAs contribute to Notch signaling pathway in T-Cell Acute Lymphoblastic Leukemia

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive T-cell malignancy characterized by genotypically-defined and phenotypically divergent cell populations, governed by adaptive landscapes. Clonal expansions are associated to genetic and epigenetic events, and modulation of external stimuli that affect the hierarchical structure of subclones and support the dynamics of leukemic subsets. Recently, small extracellular vesicles (sEV) such exosomes were also shown to play a role in leukemia. Here, by coupling miRNome, bulk and single cell transcriptome profiling, we found that T-ALL-secreted sEV contain NOTCH1-dependent microRNAs (EV-miRs), which control oncogenic pathways acting as autocrine stimuli and ultimately promoting the expansion/survival of highly proliferative cell subsets of human T-cell leukemias. Of interest, we found that NOTCH1-dependent EV-miRs mostly comprised members of miR-17-92a cluster and paralogues, which rescued in vitro the proliferation of T-ALL cells blocked by {gamma}-secretase inhibitors (GSI) and regulate network of genes characterizing patients with relapsed/refractory early T-cell progenitor (ETP) ALLs. All these findings suggest that NOTCH1 dependent EV-miRs may sustain the growth/survival of immunophenotypically defined cell populations, altering the cell heterogeneity and the dynamics of T-cell leukemias in response to conventional therapies.

cancer biology↗

bioRxiv2021

KMT2D haploinsufficiency in Kabuki Syndrome disrupts neuronal function through transcriptional and chromatin rewiring independent of H3K4-monomethylation

Kabuki syndrome (KS) is a rare multisystem disorder, characterized by intellectual disability, growth delay, and distinctive craniofacial features. It is mostly caused by de novo mutations of KMT2D, which is responsible for histone H3lysine 4 mono-methylation (H3K4me1) that marks active and poised enhancers. We assessed the impact of KMT2D mutations on chromatin and transcriptional regulation in a cohort of multiple KS1 tissues, including primary patient samples and disease-relevant lineages, namely cortical neurons (iN), neural crest stem cells (NCSC), and mesenchymal cells (MC). In parallel, we generated an isogenic line derived from human embryonic stem cells (hESC) for the stepwise characterization of neural precursors and mature neurons. We found that transcriptional dysregulation was particularly pronounced in cortical neurons and widely affected synapse activity pathways. This was consistent with highly specific alterations of spontaneous network-bursts patterns evidenced by Micro-electrode-array (MEA)-based neural network. Profiling of H3K4me1 unveiled the almost complete uncoupling between this chromatin mark and the effects on transcription, which is instead reflected by defects in H3K27ac. Finally, we identified the direct targets of KMT2D in mature cortical neurons, uncovering TEAD2 as the main mediator of KMT2D haploinsufficiency. Our results uncover the multi-tissue architecture of KS1 dysregulation and define a unique electrical phenotype and its molecular underpinnings for the cortical neuronal lineage.

genetics↗