Biology subjects

Adamo, A.

Publications and source records attributed to Adamo, A..

6 recordsLinked to original sources

bioRxiv2024

An iPSC-based model of Jacob Syndrome reveals a DNA methylation-independent transcriptional dysregulation shared with X aneuploid cells.

Male sex chromosome aneuploidies are frequent genetic aberrations in humans characterized by additional Y or X chromosome complements. Jacob (JS) and Klinefelter syndromes (KS), carrying 47,XYY and 47,XXY chromosomes, respectively, share several clinical features, including sterility, hormonal deficits, neurocognitive delay, and skeletal-muscle defects. Despite the high incidence, a complete understanding of the molecular mechanisms underlying the clinical manifestations in sex aneuploid patients is still elusive. In this study, we generated and characterized the inaugural cohort of 47,XYY human induced pluripotent stem cells (iPSCs). We performed a comprehensive transcriptional analysis, including JS primary fibroblasts, iPSCs, and neural stem cells (NSCs) alongside KS cells. Our study revealed a transcriptional feedback mechanism tuning non-PAR X chromosome genes (NPX) homologs in Y supernumerary cells, a phenomenon not detected in X aneuploid iPSCs. By ectopically modulating the expression of selected NPY genes, we demonstrated a direct transcriptional link between the UTY-UTX gene pair. Furthermore, our analyses identified a shared transcriptomic signature between JS and KS, discernible already at the iPSC stage, with a notable enrichment for processes related to neurological functions. This transcriptomic convergence underscores potential commonalities in the molecular pathways underpinning the pathophysiology of male sex chromosome aneuploidies. Finally, through genome-wide DNA methylation profiling of JS iPSCs, we demonstrated that a supernumerary Y chromosome only minimally impacts the methylation status of 47,XYY cells at the pluripotent stage. Our work reveals critical transcriptional feedback mechanisms and shared gene expression signatures in male sex chromosome aneuploidies, paving the way for a better understanding of their common phenotypic features.

cell biology↗

bioRxiv2023

Chromothripsis orchestrates leukemic transformation in blast phase MPN through targetable amplification of DYRK1A

Chromothripsis, the process of catastrophic shattering and haphazard repair of chromosomes, is a common event in cancer. Whether chromothripsis might constitute an actionable molecular event amenable to therapeutic targeting remains an open question. We describe recurrent chromothripsis of chromosome 21 in a subset of patients in blast phase of a myeloproliferative neoplasm (BP-MPN), which alongside other structural variants leads to amplification of a region of chromosome 21 in [~]25% of patients ( chr21amp). We report that chr21amp BP-MPN has a particularly aggressive and treatment-resistant phenotype. The chr21amp event is highly clonal and present throughout the hematopoietic hierarchy. DYRK1A, a serine threonine kinase and transcription factor, is the only gene in the 2.7Mb minimally amplified region which showed both increased expression and chromatin accessibility compared to non-chr21amp BP-MPN controls. We demonstrate that DYRK1A is a central node at the nexus of multiple cellular functions critical for BP-MPN development, including DNA repair, STAT signalling and BCL2 overexpression. DYRK1A is essential for BP-MPN cell proliferation in vitro and in vivo, and DYRK1A inhibition synergises with BCL2 targeting to induce BP-MPN cell apoptosis. Collectively, these findings define the chr21amp event as a prognostic biomarker in BP-MPN and link chromothripsis to a druggable target.

cancer biology↗

bioRxiv2023

Leukemic stem cells hijack lineage inappropriate signalling pathways to promote their growth

Acute Myeloid Leukemia (AML) is caused by multiple mutations which dysregulate growth and differentiation of myeloid cells. Cells adopt different gene regulatory networks specific to individual mutations, maintaining a rapidly proliferating blast cell population with fatal consequences for the patient if not treated. The most common treatment option is still chemotherapy which targets such cells. However, patients harbour a population of quiescent leukemic stem cells (LSCs) which can emerge from quiescence to trigger relapse after therapy. The processes that allow such cells to re- grow remain unknown. Here, we examined the well characterised t(8;21) AML sub-type as a model to address this question. Using a novel t(8;21) patient-derived xenograft model, we show that t(8;21) LSCs aberrantly activate the VEGF and IL-5 signalling pathways. Both pathways operate within a regulatory circuit consisting of the driver oncoprotein RUNX1::ETO and an AP-1/GATA2 axis allowing LSCs to re-enter the cell cycle while preserving self-renewal capacity.

cancer biology↗

bioRxiv2023

The axon guidance cue SEMA3A promotes the aggressive phenotype of basal-like PDAC

Pancreatic ductal adenocarcinoma (PDAC) is a lethal disease with few available therapeutic options. Two transcriptional cancer cell states have been consistently reported in PDAC, with the basal-like/squamous phenotype displaying a more aggressive biological behavior. Genetic and epigenetic dysregulation of the axon guidance pathway are common in PDAC, yet our understanding of its biological relevance is limited. Here, we investigated the functional role of the axon guidance cue SEMA3A in sustaining the progression of PDAC. We integrated available transcriptomic datasets of human PDAC with in situ hybridization analyses of patients tissues to find that SEMA3A is expressed by stromal cells and selectively enriched in epithelial cells of the basal-like/squamous subtype. We found that both cell-intrinsic and cell extrinsic factors instructing the basal-like/squamous subtype induce expression of SEMA3A in PDAC cells. In vitro, SEMA3A promoted cell migration as well as anoikis resistance. At molecular level, these phenotypes were associated with increased FAK signaling and enrichment of gene programs related to cytoskeleton remodeling. Accordingly, SEMA3A provided mouse PDAC cells with greater metastatic competence. In mouse orthotopic allografts, SEMA3A remodeled the TME by favoring infiltration of tumor-associated macrophages and exclusion of T cells. Mechanistically, SEMA3A functioned as chemoattractant for macrophages and favored their polarization towards an M2-like phenotype. In SEMA3Ahigh tumors, depletion of macrophages resulted in greater intratumor infiltration by CD8+ T cells and increased sensitivity of these tumors to chemotherapy. Overall, we show that SEMA3A contributes to the malignant phenotype of basal-like PDAC.

cancer biology↗

bioRxiv2022

Mammary Tissue-Derived Extracellular Matrix Hydrogels Reveal the Role of the Irradiated Microenvironment in Breast Cancer Recurrence

Radiation therapy (RT) is essential for triple negative breast cancer (TNBC) treatment. However, patients with TNBC continue to experience recurrence after RT. The role of the extracellular matrix (ECM) of irradiated breast tissue in tumor recurrence is still unknown. In this study, we evaluated the structure, molecular composition, and mechanical properties of irradiated murine mammary fat pads (MFPs) and developed ECM hydrogels from decellularized tissues (dECM) to assess the effects of RT-induced ECM changes on breast cancer cell behavior. Irradiated MFPs were characterized by increased ECM deposition and fiber density compared to unirradiated controls, which may provide a platform for cell invasion and proliferation. ECM component changes in collagens I, IV, and VI, and fibronectin were observed following irradiation in both MFPs and dECM hydrogels. Encapsulated TNBC cell proliferation and invasive capacity was enhanced in irradiated dECM hydrogels. In addition, TNBC cells co-cultured with macrophages in irradiated dECM hydrogels induced M2 macrophage polarization and exhibited further increases in proliferation. Our study establishes that the ECM in radiation-damaged sites promotes TNBC invasion and proliferation as well as an immunosuppressive microenvironment. This work represents an important step toward elucidating how changes in the ECM after RT contribute to breast cancer recurrence.

cancer biology↗

bioRxiv2017

The Caenorhabditis elegans RAD-51 isoform A is required for the induction of DNA-damage-dependent apoptosis

The rad-51 gene in Caenorhabditis elegans is transcribed into alternative mRNAs potentially coding three alternative protein isoforms. We have genetically modified this gene in order to investigate the potential roles of the longest isoform, namely isoform A, in genome stability. The RAD-51 isoform A appears to contribute to genome stability in late development, but is not implicated in meiosis or DNA repair in the germline. However, the RAD-51 isoform A has a pivotal role in DNA damage induced apoptosis, but not in DNA damage checkpoint activation or physiological cell death. This is a relevant new finding that improves our understanding of how DNA damage apoptosis is restricted to late pachytene stage preventing the inappropriate loss of nuclei undergoing the earlier stages of meiotic recombination, during which a large number of physiologically induced DSBs are present.

genetics↗