Publications by authors named "Giovanni Fagá"

9 Publications

  • Page 1 of 1

High-throughput screening identifies histone deacetylase inhibitors that modulate GTF2I expression in 7q11.23 microduplication autism spectrum disorder patient-derived cortical neurons.

Mol Autism 2020 11 19;11(1):88. Epub 2020 Nov 19.

High Definition Disease Modelling Lab: Stem Cell and Organoid Epigenetics, IEO, European Institute of Oncology IRCCS, Via Adamello 16, 20139, Milan, Italy.

Background: Autism spectrum disorder (ASD) is a highly prevalent neurodevelopmental condition affecting almost 1% of children, and represents a major unmet medical need with no effective drug treatment available. Duplication at 7q11.23 (7Dup), encompassing 26-28 genes, is one of the best characterized ASD-causing copy number variations and offers unique translational opportunities, because the hemideletion of the same interval causes Williams-Beuren syndrome (WBS), a condition defined by hypersociability and language strengths, thereby providing a unique reference to validate treatments for the ASD symptoms. In the above-indicated interval at 7q11.23, defined as WBS critical region, several genes, such as GTF2I, BAZ1B, CLIP2 and EIF4H, emerged as critical for their role in the pathogenesis of WBS and 7Dup both from mouse models and human studies.

Methods: We performed a high-throughput screening of 1478 compounds, including central nervous system agents, epigenetic modulators and experimental substances, on patient-derived cortical glutamatergic neurons differentiated from our cohort of induced pluripotent stem cell lines (iPSCs), monitoring the transcriptional modulation of WBS interval genes, with a special focus on GTF2I, in light of its overriding pathogenic role. The hits identified were validated by measuring gene expression by qRT-PCR and the results were confirmed by western blotting.

Results: We identified and selected three histone deacetylase inhibitors (HDACi) that decreased the abnormal expression level of GTF2I in 7Dup cortical glutamatergic neurons differentiated from four genetically different iPSC lines. We confirmed this effect also at the protein level.

Limitations: In this study, we did not address the molecular mechanisms whereby HDAC inhibitors act on GTF2I. The lead compounds identified will now need to be advanced to further testing in additional models, including patient-derived brain organoids and mouse models recapitulating the gene imbalances of the 7q11.23 microduplication, in order to validate their efficacy in rescuing phenotypes across multiple functional layers within a translational pipeline towards clinical use.

Conclusions: These results represent a unique opportunity for the development of a specific class of compounds for treating 7Dup and other forms of intellectual disability and autism.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s13229-020-00387-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7677843PMC
November 2020

Discovery of Reversible Inhibitors of KDM1A Efficacious in Acute Myeloid Leukemia Models.

ACS Med Chem Lett 2020 May 13;11(5):754-759. Epub 2020 Feb 13.

Department of Experimental Oncology, Academic Drug Discovery, European Institute of Oncology IRCCS, Via Adamello 16, 20139 Milan, Italy.

Lysine-specific demethylase 1 (LSD1 or KDM1A) is a FAD-dependent enzyme that acts as a transcription corepressor or coactivator by regulating the methylation status of histone H3 lysines K4 and K9, respectively. KDM1A represents an attractive target for cancer therapy. While, in the past, the main medicinal chemistry strategy toward KDM1A inhibition was based on the optimization of ligands that irreversibly bind the FAD cofactor within the enzyme catalytic site, we and others have also identified reversible inhibitors. Herein we reported the discovery of 5-imidazolylthieno[3,2-]pyrroles, a new series of KDM1A inhibitors endowed with picomolar inhibitory potency, active in cells and efficacious after oral administration in murine leukemia models.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acsmedchemlett.9b00604DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7236255PMC
May 2020

ATR expands embryonic stem cell fate potential in response to replication stress.

Elife 2020 03 12;9. Epub 2020 Mar 12.

IFOM-The FIRC Institute of Molecular Oncology, Milan, Italy.

Unrepaired DNA damage during embryonic development can be potentially inherited by a large population of cells. However, the quality control mechanisms that minimize the contribution of damaged cells to developing embryos remain poorly understood. Here, we uncovered an ATR- and CHK1-mediated transcriptional response to replication stress (RS) in mouse embryonic stem cells (ESCs) that induces genes expressed in totipotent two-cell (2C) stage embryos and 2C-like cells. This response is mediated by , a multicopy retrogene defining the cleavage-specific transcriptional program in placental mammals. In response to RS, DUX triggers the transcription of 2C-like markers such as murine endogenous retrovirus-like elements (MERVL) and . This response can also be elicited by ETAA1-mediated ATR activation in the absence of RS. ATR-mediated activation of DUX requires GRSF1-dependent post-transcriptional regulation of mRNA. Strikingly, activation of ATR expands ESCs fate potential by extending their contribution to both embryonic and extra-embryonic tissues. These findings define a novel ATR dependent pathway involved in maintaining genome stability in developing embryos by controlling ESCs fate in response to RS.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.7554/eLife.54756DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7067586PMC
March 2020

Thieno[3,2-b]pyrrole-5-carboxamides as New Reversible Inhibitors of Histone Lysine Demethylase KDM1A/LSD1. Part 2: Structure-Based Drug Design and Structure-Activity Relationship.

J Med Chem 2017 03 27;60(5):1693-1715. Epub 2017 Feb 27.

Department of Experimental Oncology, Academic Drug Discovery, European Institute of Oncology , Via Adamello 16, 20139 Milano, Italy.

The balance of methylation levels at histone H3 lysine 4 (H3K4) is regulated by KDM1A (LSD1). KDM1A is overexpressed in several tumor types, thus representing an emerging target for the development of novel cancer therapeutics. We have previously described ( Part 1, DOI 10.1021.acs.jmedchem.6b01018 ) the identification of thieno[3,2-b]pyrrole-5-carboxamides as novel reversible inhibitors of KDM1A, whose preliminary exploration resulted in compound 2 with biochemical IC = 160 nM. We now report the structure-guided optimization of this chemical series based on multiple ligand/KDM1A-CoRest cocrystal structures, which led to several extremely potent inhibitors. In particular, compounds 46, 49, and 50 showed single-digit nanomolar IC values for in vitro inhibition of KDM1A, with high selectivity in secondary assays. In THP-1 cells, these compounds transcriptionally affected the expression of genes regulated by KDM1A such as CD14, CD11b, and CD86. Moreover, 49 and 50 showed a remarkable anticlonogenic cell growth effect on MLL-AF9 human leukemia cells.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.jmedchem.6b01019DOI Listing
March 2017

Thieno[3,2-b]pyrrole-5-carboxamides as New Reversible Inhibitors of Histone Lysine Demethylase KDM1A/LSD1. Part 1: High-Throughput Screening and Preliminary Exploration.

J Med Chem 2017 03 27;60(5):1673-1692. Epub 2017 Feb 27.

Department of Experimental Oncology, Academic Drug Discovery, European Institute of Oncology , Via Adamello 16, 20139 Milano, Italy.

Lysine specific demethylase 1 KDM1A (LSD1) regulates histone methylation and it is increasingly recognized as a potential therapeutic target in oncology. We report on a high-throughput screening campaign performed on KDM1A/CoREST, using a time-resolved fluorescence resonance energy transfer (TR-FRET) technology, to identify reversible inhibitors. The screening led to 115 hits for which we determined biochemical IC, thus identifying four chemical series. After data analysis, we have prioritized the chemical series of N-phenyl-4H-thieno[3, 2-b]pyrrole-5-carboxamide for which we obtained X-ray structures of the most potent hit (compound 19, IC = 2.9 μM) in complex with the enzyme. Initial expansion of this chemical class, both modifying core structure and decorating benzamide moiety, was directed toward the definition of the moieties responsible for the interaction with the enzyme. Preliminary optimization led to compound 90, which inhibited the enzyme with a submicromolar IC (0.162 μM), capable of inhibiting the target in cells.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.jmedchem.6b01018DOI Listing
March 2017

Selective transcriptional regulation by Myc in cellular growth control and lymphomagenesis.

Nature 2014 Jul 9;511(7510):488-492. Epub 2014 Jul 9.

Center for Genomic Science of IIT@SEMM, Fondazione Istituto Italiano di Tecnologia (IIT), Via Adamello 16, 20139 Milan, Italy.

The c-myc proto-oncogene product, Myc, is a transcription factor that binds thousands of genomic loci. Recent work suggested that rather than up- and downregulating selected groups of genes, Myc targets all active promoters and enhancers in the genome (a phenomenon termed 'invasion') and acts as a general amplifier of transcription. However, the available data did not readily discriminate between direct and indirect effects of Myc on RNA biogenesis. We addressed this issue with genome-wide chromatin immunoprecipitation and RNA expression profiles during B-cell lymphomagenesis in mice, in cultured B cells and fibroblasts. Consistent with long-standing observations, we detected general increases in total RNA or messenger RNA copies per cell (hereby termed 'amplification') when comparing actively proliferating cells with control quiescent cells: this was true whether cells were stimulated by mitogens (requiring endogenous Myc for a proliferative response) or by deregulated, oncogenic Myc activity. RNA amplification and promoter/enhancer invasion by Myc were separable phenomena that could occur without one another. Moreover, whether or not associated with RNA amplification, Myc drove the differential expression of distinct subsets of target genes. Hence, although having the potential to interact with all active or poised regulatory elements in the genome, Myc does not directly act as a global transcriptional amplifier. Instead, our results indicate that Myc activates and represses transcription of discrete gene sets, leading to changes in cellular state that can in turn feed back on global RNA production and turnover.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/nature13537DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4110711PMC
July 2014

TGFβ-dependent gene expression shows that senescence correlates with abortive differentiation along several lineages in Myc-induced lymphomas.

Cell Cycle 2010 Dec;9(23):4622-6

Theodor Boveri Institute, Biocenter, University of Würzburg, Würzburg, Germany.

Deregulated expression of Myc under the control of an immunoglobulin enhancer induces lymphoma formation in mice. The development of lymphomas is limited by TGFβ-dependent senescence and high levels of Myc expression are continuously required to antagonize senescence. The biological processes underlying senescence are not fully resolved. We report here a comprehensive analysis of TGFβ-dependent alterations in gene expression when the Myc transgene is switched off. Our data show that Myc-induced target genes are downregulated in a TGFβ-independent manner. In contrast, TGFβ is required to upregulate a broad spectrum of genes that are characteristic of different T-cell lineages when Myc is turned off. The analysis reveals a significant overlap between these Myc-repressed genes with genes that are targets of polycomb repressive complexes in embryonic stem cells. Therefore, TGFβ-dependent senescence is associated with gene expression patterns indicative of abortive cellular differentiation along several lineages.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.4161/cc.9.23.14211DOI Listing
December 2010

Myc, Cdk2 and cellular senescence: Old players, new game.

Cell Cycle 2010 Sep 15;9(18):3655-61. Epub 2010 Sep 15.

Department of Experimental Oncology, European Institute of Oncology (IEO), IFOM-IEO Campus, Milan, Italy.

The aberrant activation of oncogenic pathways promotes tumor progression, but concomitantly elicits compensatory tumor-suppressive responses, such as apoptosis or senescence. For example, Ras induces senescence, while Myc generally triggers apoptosis. Myc is in fact viewed as an anti-senescence oncogene, as it is a potent inducer of cell proliferation and immortalization, bypasses growth-inhibitory signals, and cooperates with Ras in cellular transformation. Recent reports prompt re-evaluation of Myc-induced senescence and of its role in tumor progression and therapy. We have shown that the cyclin-dependent kinase Cdk2, although redundant for cell cycle progression, has a unique role in suppressing a Myc-induced senescence program: Myc activation elicited expression of p16(INK4a) and p21(Cip1), and caused senescence in cells lacking Cdk2, but not in Cdk2-proficient cells. We show here that suppression of Myc-induced senescence by Cdk2 does not occur through phosphorylation of its purported substrate residue in Myc (Ser 62). Additional cellular activities have been identified that suppress Myc-induced senescence, including the Wrn helicase, Telomerase and Miz1. These senescencesuppressing activities were critical for tumor progression, as deficiency in either Cdk2, telomerase or Miz1 reduced the onset of Myc-induced lymphoma in transgenic mice. Other gene products like p53, SUV39H1 or TGFβ promoted senescence, which together with apoptosis contributed to tumor suppression. Paradoxically, Myc directly counteracted the very same senescence program that it potentially elicited, since it positively regulated Wrn, Telomerase and Cdk2 activity. Furthermore, Cdk2 inhibition re-activated the latent senescence program in Myc expressing cells. Hence, while these molecules are instrumental to the oncogenic action of Myc, they may simultaneously constitute its Achille's heel for therapeutic development.
View Article and Find Full Text PDF

Download full-text PDF

Source
September 2010

Pathogenic effects of human herpesvirus 6 in human lymphoid tissue ex vivo.

J Virol 2003 Aug;77(15):8280-9

Laboratory of Cellular and Molecular Biophysics, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA.

Human herpesvirus 6 (HHV-6) is a potentially immunosuppressive agent that has been suggested to act as a cofactor in the progression of human immunodeficiency virus disease. However, the lack of suitable experimental models has hampered the elucidation of the mechanisms of HHV-6-mediated immune suppression. Here, we used ex vivo lymphoid tissue to investigate the cellular tropism and pathogenic mechanisms of HHV-6. Viral strains belonging to both HHV-6 subgroups (A and B) were able to productively infect human tonsil tissue fragments in the absence of exogenous stimulation. The majority of viral antigen-expressing cells were CD4(+) T lymphocytes expressing a nonnaive phenotype, while CD8(+) T cells were efficiently infected only with HHV-6A. Accordingly, HHV-6A infection resulted in the depletion of both CD4(+) and CD8(+) T cells, whereas in HHV-6B-infected tissue CD4(+) T cells were predominantly depleted. The expression of different cellular antigens was dramatically altered in HHV-6-infected tissues: whereas CD4 was upregulated, both CD46, which serves as a cellular receptor for HHV-6, and CD3 were downmodulated. However, CD3 downmodulation was restricted to infected cells, while the loss of CD46 expression was generalized. Moreover, HHV-6 infection markedly enhanced the production of the CC chemokine RANTES, whereas other cytokines and chemokines were only marginally affected. These results provide the first evidence, in a physiologically relevant study model, that HHV-6 can severely affect the physiology of secondary lymphoid organs through direct infection of T lymphocytes and modulation of key membrane receptors and chemokines.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC165251PMC
http://dx.doi.org/10.1128/jvi.77.15.8280-8289.2003DOI Listing
August 2003