Papers by Monica Faronato
An important aspect of tumor progression is the ability of cancer cells to escape detection and c... more An important aspect of tumor progression is the ability of cancer cells to escape detection and clearance by the immune system. Recent studies suggest that several tumors express soluble factors interfering with the immune response. Here, we show that semaphorin-3A (Sema-3A), a secreted member of the semaphorin family involved in axonal guidance, organogenesis, and angiogenesis, is highly expressed in several tumor cells. Conditioned media of Sema-3A-transfected COS-7 cells or human recombinant Sema-3A inhibited primary human T-cell proliferation and cytokines production under anti-CD3 plus anti-CD28 stimulating conditions. Sema-3A also inhibited the activation of nonspecific cytotoxic activity in mixed lymphocyte culture (MLC), as measured against K-562 cells. In contrast, suppression of Sema-3A in tumor cells with a small interfering RNA (siRNA) augmented T-cell activation. The inhibitory effect of Sema-3A in T cells is mediated by blockade of Ras/mitogenactivated protein kinase (MAPK) signaling pathway. The presence of Sema-3A increased the activation of the Ras family small GTPase Rap1 and introduction of the dominant-negative mutant of Rap1 (Rap1N17) blunted the immunoinhibitory effects of Sema-3A. These results suggest that Sema-3A inhibits primary T-cell activation and imply that it can contribute to the T-cell dysfunction in the tumor microenvironment. (Blood. 2006;107: 3321-3329)
Nature communications, Jan 27, 2015
Endocrine therapies target the activation of the oestrogen receptor alpha (ERα) via distinct mech... more Endocrine therapies target the activation of the oestrogen receptor alpha (ERα) via distinct mechanisms, but it is not clear whether breast cancer cells can adapt to treatment using drug-specific mechanisms. Here we demonstrate that resistance emerges via drug-specific epigenetic reprogramming. Resistant cells display a spectrum of phenotypical changes with invasive phenotypes evolving in lines resistant to the aromatase inhibitor (AI). Orthogonal genomics analysis of reprogrammed regulatory regions identifies individual drug-induced epigenetic states involving large topologically associating domains (TADs) and the activation of super-enhancers. AI-resistant cells activate endogenous cholesterol biosynthesis (CB) through stable epigenetic activation in vitro and in vivo. Mechanistically, CB sparks the constitutive activation of oestrogen receptors alpha (ERα) in AI-resistant cells, partly via the biosynthesis of 27-hydroxycholesterol. By targeting CB using statins, ERα binding is re...
Atlas of Genetics and Cytogenetics in Oncology and Haematology, 2012
Note USP15 is a member of the ubiquitin-specific protease (USP) family; these cysteine proteases ... more Note USP15 is a member of the ubiquitin-specific protease (USP) family; these cysteine proteases comprise the largest sub-group of deubiquitinase enzymes (DUBs). USP15 cleaves the isopeptide bonds of polyubiquitin chains, and can cleave linear ubiquitin fusion proteins . The USP15 gene spans 145 kb of genomic DNA. Four transcripts of the human USP15 gene are described by Ensembl and are summarized in the accompanying diagram and table. According to Entrezgene, USP15 encodes a single reference sequence mRNA of 4611bp (NM_006313.1) composed of 21 exons, which corresponds to USP15-203. However, three other USP15 splice variants utilise several alternative-splicing sites between exon 5 and exon 7 of this reference sequence. USP15-201, a 4698 bp mRNA comprised of 22 exons, is expressed at similar levels to the reference sequence . Expression of the remaining variants, USP15-204 and the truncated USP15-202, is less well studied. Schematic illustrating four human USP15 transcripts. The USP15 reference sequence mRNA (USP15-203) and three alternative splice variants are illustrated. The approximate position and size of exons within the USP15 gene, according to Ensembl, is shown for each splice variant. USP15 (ubiquitin specific peptidase 15) Faronato M, et al.
Atlas of Genetics and Cytogenetics in Oncology and Haematology, 2011
The REST gene spans 24 kb of genomic DNA. It is composed of: three alternative 5' non-coding exon... more The REST gene spans 24 kb of genomic DNA. It is composed of: three alternative 5' non-coding exons associated with different gene promoters, three coding exons, an internal alternative exon that is spliced into some neural and disease associated transcripts. According to Entrezgene the REST gene encodes a single reference sequence mRNA of 3663 bp (NM_005612.3) that is composed of four exons. However, the literature indicates that at least six different splice variants of REST exist and are associated with neural gene expression and certain disease states. Schematic illustrating REST mRNA and alternative splice variants. The human REST gene is shown (top) illustrating the three main exons (dark blue), an alternative exon (light blue) and one of three alternative 5' non-coding exons (white). The approximate position of sequence encoding eight zinc fingers are illustrated by boxes, these are associated with DNA binding (white) or nuclear import (red). Six alternative mRNAs are illustrated below, the REST reference sequence (NM_005612.3) codes for the major isoform 1. Splice variants described in human *neuroblastoma or **SCLC are also shown. REST 1 and REST-5F∆ code for isoform 2 or isoform 4 respectively. The alternative exon in REST-N62, REST-N4 and sNRSF (N50) introduces a premature stop codon and all three transcripts encode isoform 3 (sNRSF/REST4).
Oncotarget, Jan 15, 2015
Over 30% of ERα breast cancer patients develop relapses and progress to metastatic disease despit... more Over 30% of ERα breast cancer patients develop relapses and progress to metastatic disease despite treatment with endocrine therapies. The pioneer factor PBX1 translates epigenetic cues and mediates estrogen induced ERα binding. Here we demonstrate that PBX1 plays a central role in regulating the ERα transcriptional response to epidermal growth factor (EGF) signaling. PBX1 regulates a subset of EGF-ERα genes highly expressed in aggressive breast tumours. Retrospective stratification of luminal patients using PBX1 protein levels in primary cancer further demonstrates that elevated PBX1 protein levels correlate with earlier metastatic progression. In agreement, PBX1 protein levels are significantly upregulated during metastatic progression in ERα-positive breast cancer patients. Finally we reveal that PBX1 upregulation in aggressive tumours is partly mediated by genomic amplification of the PBX1 locus. Correspondingly, ERα positive breast cancer patients carrying PBX1 amplification ar...
Oncotarget, Jan 4, 2015
The acquisition of endocrine therapy resistance in estrogen receptor α (ERα) breast cancer patien... more The acquisition of endocrine therapy resistance in estrogen receptor α (ERα) breast cancer patients represents a major clinical problem. Notch signalling has been extensively linked to breast cancer especially in patients who fail to respond to endocrine therapy. Following activation, Notch intracellular domain is released and enters the nucleus where activates transcription of target genes. The numerous steps that cascade after activation of the receptor complicate using Notch as biomarker. Hence, this warrants the development of reliable indicators of Notch activity. DMXL2 is a novel regulator of Notch signalling not yet investigated in breast cancer. Here, we demonstrate that DMXL2 is overexpressed in a subset of endocrine therapy resistant breast cancer cell lines where it promotes epithelial to mesenchymal transition through hyper-activation of Notch signalling via V-ATPase dependent acidification. Following DMXL2 depletion or treatment with Bafilomycin A1, both EMT targets and...
Breast Cancer Research and Treatment, 2014
Breast Cancer Research and Treatment, 2014
The goal of targeted cancer therapies is to specifically block oncogenic signalling, thus maximis... more The goal of targeted cancer therapies is to specifically block oncogenic signalling, thus maximising efficacy, while reducing side-effects to patients. The gamma-secretase (GS) complex is an attractive therapeutic target in haematological malignancies and solid tumours with major pharmaceutical activity to identify optimal inhibitors. Within GS, nicastrin (NCSTN) offers an opportunity for therapeutic intervention using blocking monoclonal antibodies (mAbs). Here we explore the role of anti-nicastrin monoclonal antibodies, which we have developed as specific, multi-faceted inhibitors of proliferation and invasive traits of triple-negative breast cancer cells. We use 3D in vitro proliferation and invasion assays as well as an orthotopic and tail vail injection triple-negative breast cancer in vivo xenograft model systems. RNAScope assessed nicastrin in patient samples. Anti-NCSTN mAb clone-2H6 demonstrated a superior anti-tumour efficacy than clone-10C11 and the RO4929097 small molecule GS inhibitor, acting by inhibiting GS enzymatic activity and Notch signalling in vitro and in vivo. Confirming clinical relevance of nicastrin as a target, we report evidence of increased NCSTN mRNA levels by RNA in situ hybridization (RNAScope) in a large cohort of oestrogen receptor negative breast cancers, conferring independent prognostic significance for disease-free survival, in multivariate analysis. We demonstrate here that targeting NCSTN using specific mAbs may represent a novel mode of treatment for invasive triple-negative breast cancer, for which there are few targeted therapeutic options. Furthermore, we propose that measuring NCSTN in patient samples using RNAScope technology may serve as companion diagnostic for anti-NCSTN therapy in the clinic.
Cell Cycle, 2013
Reversible ubiquitylation of proteins contributes to their integrity, abundance and activity. the... more Reversible ubiquitylation of proteins contributes to their integrity, abundance and activity. the Re1-silencing transcription factor (ReSt) plays key physiological roles and is dysregulated in a spectrum of disease. It is rapidly turned over and is phosphorylated, polyubiquitylated and degraded en masse during neuronal differentiation and cell cycle progression. through siRNA screening we identified the deubiquitylase USp15 as a key regulator of cellular ReSt. Both antagonism of ReSt polyubiquitylation and rescue of endogenous ReSt levels are dependent on the deubiquitylase activity of USp15. However, USp15 depletion does not destabilize pre-existing ReSt, but rather specifically impairs de novo ReSt synthesis. Indeed, we find that a small fraction of endogenous USp15 is associated with polysomes. In accordance with these findings, USp15 does not antagonize the degradation of phosphorylated ReSt at mitosis. Instead it is required for the rapid accumulation of newly synthesized ReSt on mitotic exit, thus playing a key role in its cell cycle oscillations. Importantly, this study reveals a novel role for a DUB in specifically promoting new protein synthesis.
Blood, 2006
An important aspect of tumor progression is the ability of cancer cells to escape detection and c... more An important aspect of tumor progression is the ability of cancer cells to escape detection and clearance by the immune system. Recent studies suggest that several tumors express soluble factors interfering with the immune response. Here, we show that semaphorin-3A (Sema-3A), a secreted member of the semaphorin family involved in axonal guidance, organogenesis, and angiogenesis, is highly expressed in several tumor cells. Conditioned media of Sema-3A-transfected COS-7 cells or human recombinant Sema-3A inhibited primary human T-cell proliferation and cytokines production under anti-CD3 plus anti-CD28 stimulating conditions. Sema-3A also inhibited the activation of nonspecific cytotoxic activity in mixed lymphocyte culture (MLC), as measured against K-562 cells. In contrast, suppression of Sema-3A in tumor cells with a small interfering RNA (siRNA) augmented T-cell activation. The inhibitory effect of Sema-3A in T cells is mediated by blockade of Ras/mitogen-activated protein kinase ...
Human neoplastic mesothelial cells express voltage-gated sodium channels involved in cell motility
The International Journal of Biochemistry & Cell Biology, 2006
Given the pivotal role of ion channels in neoplastic transformation, the aim of the present study... more Given the pivotal role of ion channels in neoplastic transformation, the aim of the present study has been to assess possible differences in the expression patterns of voltage-gated monovalent cationic (Na(+) and K(+)) currents between normal and neoplastic mesothelial cells (NM, MPM, respectively), and to evaluate the role of specific ion channels in mesothelioma cells proliferation, apoptosis, and motility. To achieve this aim, membrane currents expressed in NM and MPM cells derived from surgically-removed human specimens were investigated by means of patch-clamp electrophysiology. NM cells were found to express three main classes of K(+) currents, which were defined as K(IR), maxiK(Ca), and K(V) currents on the basis of their biophysical and pharmacological properties. Each of these K(+) currents was absent in MPM cells; by contrast, MPM cells revealed the novel appearance of tetrodotoxin (TTX)-sensitive voltage-gated Na(+) currents undetected in normal mesothelial cells. Reverse transcriptase-polymerase chain reaction (RT-PCR) and real-time PCR analysis of MPM cells transcripts showed significant expression of the mRNAs encoding for Na(V)1.2, and Na(V)1.6, and Na(V)1.7 (and less so for Na(V)1.3, Na(V)1.4, and Na(V)1.5) main voltage-gated sodium channel (VGSC) alpha-subunit(s). Interestingly, blockade of VGSCs with TTX decreased mesothelioma cell migration in in vitro motility assays; on the other hand, TTX failed to interfere with cell viability, proliferation, and apoptosis progression triggered by UV exposure. In summary, the results of the present study suggest that VGSCs expression in MPM cells may favor the increased motility of the neoplastic cells, a phenotypic feature often associated with the malignant phenotype.
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Papers by Monica Faronato