Publications by authors named "Franco Izzo"

13 Publications

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Canonical ErbB-2 isoform and ErbB-2 variant c located in the nucleus drive triple negative breast cancer growth.

Oncogene 2020 09 25;39(39):6245-6262. Epub 2020 Aug 25.

Laboratory of Molecular Mechanisms of Carcinogenesis and Molecular Endocrinology, Instituto de Biología y Medicina Experimental (IBYME), CONICET, Vuelta de Obligado 2490, C1428ADN, Buenos Aires, Argentina.

Triple negative breast cancer (TNBC) refers to tumors that do not express clinically significant levels of estrogen and progesterone receptors, and lack membrane overexpression or gene amplification of ErbB-2/HER2, a receptor tyrosine kinase. Transcriptome and proteome heterogeneity of TNBC poses a major challenge to precision medicine. Clinical biomarkers and targeted therapies for this disease remain elusive, so chemotherapy has been the standard of care for early and metastatic TNBC. Our present findings placed ErbB-2 in an unanticipated scenario: the nucleus of TNBC (NErbB-2). Our study on ErbB-2 alternative splicing events, using a PCR-sequencing approach combined with an RNA interference strategy, revealed that TNBC cells express either the canonical (wild-type) ErbB-2, encoded by transcript variant 1, or the non-canonical ErbB-2 isoform c, encoded by alternative variant 3 (RefSeq), or both. These ErbB-2 isoforms function in the nucleus as transcription factors. Evicting both from the nucleus or silencing isoform c only, blocks TN cell and tumor growth. This reveals not only NErbB-2 canonical and alternative isoforms role as targets of therapy in TNBC, but also isoform c dominant oncogenic potential. Furthermore, we validated our findings in the clinic and observed that NErbB-2 correlates with poor prognosis in primary TN tumors, disclosing NErbB-2 as a novel biomarker for TNBC. Our discoveries challenge the present scenario of drug development for personalized BC medicine that focuses on wild-type RefSeq proteins, which conserve the canonical domains and are located in their classical cellular compartments.
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http://dx.doi.org/10.1038/s41388-020-01430-9DOI Listing
September 2020

Nuclear PDCD4 Expression Defines a Subset of Luminal B-Like Breast Cancers with Good Prognosis.

Horm Cancer 2020 10 6;11(5-6):218-239. Epub 2020 Jul 6.

Laboratory of Molecular Mechanisms of Carcinogenesis and Molecular Endocrinology, Instituto de Biología y Medicina Experimental (IBYME), CONICET, Vuelta de Obligado 2490, C1428ADN, Buenos Aires, Argentina.

The hormone receptor-positive (estrogen and/or progesterone receptor (PR)-positive) and HER2-negative breast cancer (BC) subtype is a biologically heterogeneous entity that includes luminal A-like (LumA-like) and luminal B-like (LumB-like) subtypes. Decreased PR levels is a distinctive biological feature of LumB-like tumors. These tumors also show reduced sensitivity to endocrine therapies and poorer prognosis than LumA-like tumors. Identification of biomarkers to accurately predict disease relapse in these subtypes is crucial in order to select effective therapies. We identified the tumor suppressor PDCD4 (programmed cell death 4), located in the nucleus (NPDCD4), as an independent prognostic factor of good clinical outcome in LumA-like and LumB-like subtypes. NPDCD4-positive LumB-like tumors presented overall and disease-free survival rates comparable to those of NPDCD4-positive LumA-like tumors, indicating that NPDCD4 improves the outcome of LumB-like patients. In contrast, NPDCD4 loss increased the risk of disease recurrence and death in LumB-like compared with LumA-like tumors. This, along with our results showing that LumB-like tumors present lower NPDCD4 positivity than LumA-like tumors, suggests that NPDCD4 loss contributes to endocrine therapy resistance in LumB-like BCs. We also revealed that PR induces PDCD4 transcription in LumB-like BC, providing a mechanistic explanation to the low PDCD4 levels in LumB-like BCs lacking PR. Finally, PDCD4 silencing enhanced BC cell survival in a patient-derived explant model of LumB-like disease. Our discoveries highlight NPDCD4 as a novel biomarker in LumA- and LumB-like subtypes, which could be included in the panel of immunohistochemical markers used in the clinic to accurately predict the prognosis of LumB-like tumors.
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http://dx.doi.org/10.1007/s12672-020-00392-4DOI Listing
October 2020

Acute Myeloid Leukemia iPSCs Reveal a Role for RUNX1 in the Maintenance of Human Leukemia Stem Cells.

Cell Rep 2020 06;31(9):107688

Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Black Family Stem Cell Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA. Electronic address:

Leukemia stem cells (LSCs) are believed to have more distinct vulnerabilities than the bulk acute myeloid leukemia (AML) cells, but their rarity and the lack of universal markers for their prospective isolation hamper their study. We report that genetically clonal induced pluripotent stem cells (iPSCs) derived from an AML patient and characterized by exceptionally high engraftment potential give rise, upon hematopoietic differentiation, to a phenotypic hierarchy. Through fate-tracking experiments, xenotransplantation, and single-cell transcriptomics, we identify a cell fraction (iLSC) that can be isolated prospectively by means of adherent in vitro growth that resides on the apex of this hierarchy and fulfills the hallmark features of LSCs. Through integrative genomic studies of the iLSC transcriptome and chromatin landscape, we derive an LSC gene signature that predicts patient survival and uncovers a dependency of LSCs, across AML genotypes, on the RUNX1 transcription factor. These findings can empower efforts to therapeutically target AML LSCs.
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http://dx.doi.org/10.1016/j.celrep.2020.107688DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7786450PMC
June 2020

DNA methylation disruption reshapes the hematopoietic differentiation landscape.

Nat Genet 2020 04 23;52(4):378-387. Epub 2020 Mar 23.

New York Genome Center, New York, NY, USA.

Mutations in genes involved in DNA methylation (DNAme; for example, TET2 and DNMT3A) are frequently observed in hematological malignancies and clonal hematopoiesis. Applying single-cell sequencing to murine hematopoietic stem and progenitor cells, we observed that these mutations disrupt hematopoietic differentiation, causing opposite shifts in the frequencies of erythroid versus myelomonocytic progenitors following Tet2 or Dnmt3a loss. Notably, these shifts trace back to transcriptional priming skews in uncommitted hematopoietic stem cells. To reconcile genome-wide DNAme changes with specific erythroid versus myelomonocytic skews, we provide evidence in support of differential sensitivity of transcription factors due to biases in CpG enrichment in their binding motif. Single-cell transcriptomes with targeted genotyping showed similar skews in transcriptional priming of DNMT3A-mutated human clonal hematopoiesis bone marrow progenitors. These data show that DNAme shapes the topography of hematopoietic differentiation, and support a model in which genome-wide methylation changes are transduced to differentiation skews through biases in CpG enrichment of the transcription factor binding motif.
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http://dx.doi.org/10.1038/s41588-020-0595-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7216752PMC
April 2020

Inhibition of EZH2 Catalytic Activity Selectively Targets a Metastatic Subpopulation in Triple-Negative Breast Cancer.

Cell Rep 2020 01;30(3):755-770.e6

Department of Cardiothoracic Surgery, Weill Cornell Medicine, 525 East 68(th) Street, New York, NY 10065, USA; Meyer Cancer Center, Weill Cornell Medicine, 1300 York Avenue, New York, NY 10065, USA; Department of Cell and Developmental Biology, Weill Cornell Medicine, 1300 York Avenue, New York, NY 10065, USA. Electronic address:

Epigenetic changes are increasingly being appreciated as key events in breast cancer progression. However, breast cancer subtype-specific epigenetic regulation remains poorly investigated. Here we report that EZH2 is a leading candidate of epigenetic modulators associated with the TNBC subtype and that it predicts poor overall survival in TNBC patients. We demonstrate that specific pharmacological or genetic inhibition of EZH2 catalytic activity impairs distant metastasis. We further define a specific EZH2 population with enhanced invasion, mammosphere formation, and metastatic potential that exhibits marked sensitivity to EZH2 inhibition. Mechanistically, EZH2 inhibition differentiates EZH2 basal cells to a luminal-like phenotype by derepressing GATA3 and renders them sensitive to endocrine therapy. Furthermore, dissection of human TNBC heterogeneity shows that EZH2 basal-like 1 and mesenchymal subtypes have exquisite sensitivity to EZH2 inhibition compared with the EZH2 luminal androgen receptor subtype. These preclinical findings provide a rationale for clinical development of EZH2 as a targeted therapy against TNBC metastasis.
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http://dx.doi.org/10.1016/j.celrep.2019.12.056DOI Listing
January 2020

EpiMethylTag: simultaneous detection of ATAC-seq or ChIP-seq signals with DNA methylation.

Genome Biol 2019 11 21;20(1):248. Epub 2019 Nov 21.

New York University Langone Health, New York, NY, USA.

Activation of regulatory elements is thought to be inversely correlated with DNA methylation levels. However, it is difficult to determine whether DNA methylation is compatible with chromatin accessibility or transcription factor (TF) binding if assays are performed separately. We developed a fast, low-input, low sequencing depth method, EpiMethylTag, that combines ATAC-seq or ChIP-seq (M-ATAC or M-ChIP) with bisulfite conversion, to simultaneously examine accessibility/TF binding and methylation on the same DNA. Here we demonstrate that EpiMethylTag can be used to study the functional interplay between chromatin accessibility and TF binding (CTCF and KLF4) at methylated sites.
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http://dx.doi.org/10.1186/s13059-019-1853-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6868874PMC
November 2019

mA RNA Methylation Maintains Hematopoietic Stem Cell Identity and Symmetric Commitment.

Cell Rep 2019 08;28(7):1703-1716.e6

Molecular Pharmacology Program, Center for Cell Engineering, Center for Stem Cell Biology, Center for Experimental Therapeutics, Center for Hematologic Malignancies, Memorial Sloan Kettering Cancer Center, New York, NY, USA. Electronic address:

Stem cells balance cellular fates through asymmetric and symmetric divisions in order to self-renew or to generate downstream progenitors. Symmetric commitment divisions in stem cells are required for rapid regeneration during tissue damage and stress. The control of symmetric commitment remains poorly defined. Using single-cell RNA sequencing (scRNA-seq) in combination with transcriptomic profiling of HSPCs (hematopoietic stem and progenitor cells) from control and mA methyltransferase Mettl3 conditional knockout mice, we found that mA-deficient hematopoietic stem cells (HSCs) fail to symmetrically differentiate. Dividing HSCs are expanded and are blocked in an intermediate state that molecularly and functionally resembles multipotent progenitors. Mechanistically, RNA methylation controls Myc mRNA abundance in differentiating HSCs. We identified MYC as a marker for HSC asymmetric and symmetric commitment. Overall, our results indicate that RNA methylation controls symmetric commitment and cell identity of HSCs and may provide a general mechanism for how stem cells regulate differentiation fate choice.
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http://dx.doi.org/10.1016/j.celrep.2019.07.032DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6818972PMC
August 2019

Somatic mutations and cell identity linked by Genotyping of Transcriptomes.

Nature 2019 07 3;571(7765):355-360. Epub 2019 Jul 3.

New York Genome Center, New York, NY, USA.

Defining the transcriptomic identity of malignant cells is challenging in the absence of surface markers that distinguish cancer clones from one another, or from admixed non-neoplastic cells. To address this challenge, here we developed Genotyping of Transcriptomes (GoT), a method to integrate genotyping with high-throughput droplet-based single-cell RNA sequencing. We apply GoT to profile 38,290 CD34 cells from patients with CALR-mutated myeloproliferative neoplasms to study how somatic mutations corrupt the complex process of human haematopoiesis. High-resolution mapping of malignant versus normal haematopoietic progenitors revealed an increasing fitness advantage with myeloid differentiation of cells with mutated CALR. We identified the unfolded protein response as a predominant outcome of CALR mutations, with a considerable dependency on cell identity, as well as upregulation of the NF-κB pathway specifically in uncommitted stem cells. We further extended the GoT toolkit to genotype multiple targets and loci that are distant from transcript ends. Together, these findings reveal that the transcriptional output of somatic mutations in myeloproliferative neoplasms is dependent on the native cell identity.
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http://dx.doi.org/10.1038/s41586-019-1367-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6782071PMC
July 2019

Genetic and epigenetic determinants of B-cell lymphoma evolution.

Curr Opin Hematol 2016 07;23(4):392-401

aMeyer Cancer Center, Weill Cornell Medicine bNew York Genome Center, New York, New York, USA cInstituto de Biología y Medicina Experimental (IBYME), CONICET, Buenos Aires, Argentina.

Purpose Of Review: The success of targeted therapies fostered the development of increasingly specific and effective therapeutics for B-cell malignancies. However, cancer plasticity facilitates disease relapse, whereby intratumoral heterogeneity fuels tumor evolution into a more aggressive and resistant form. Understanding cancer heterogeneity and the evolutionary processes underlying disease relapse is key for overcoming this limitation of current treatment strategies. In the present review, we delineate the current understanding of cancer evolution and the advances in both genetic and epigenetic fields, with a focus on non-Hodgkin B-cell lymphomas.

Recent Findings: The use of massively parallel sequencing has provided insights into tumor heterogeneity, allowing determination of intratumoral genetic and epigenetic variability and identification of cancer driver mutations and (epi-)mutations. Increased heterogeneity prior to treatment results in faster disease relapse, and in many cases studying pretreatment clonal admixtures predicts the future evolutionary trajectory of relapsed disease.

Summary: Understanding the mechanisms underlying tumor heterogeneity and evolution provides valuable tools for the design of therapy within an evolutionary framework. This framework will ultimately aid in accurately predicting the evolutionary paths of B-cell malignancies, thereby guiding therapeutic strategies geared at directly anticipating and addressing cancer evolution.
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http://dx.doi.org/10.1097/MOH.0000000000000258DOI Listing
July 2016

Heregulin Co-opts PR Transcriptional Action Via Stat3 Role As a Coregulator to Drive Cancer Growth.

Mol Endocrinol 2015 Oct 4;29(10):1468-85. Epub 2015 Sep 4.

Instituto de Biología y Medicina Experimental (C.J.P., F.I., M.C.D.F., R.C.R., L.V., M.F.M., M.D.M., R.S., P.V.E.), National Council of Scientific Research, Buenos Aires, 1428 ADN Argentina; Departamento de Anatomía Patológica (Scientific and Technological Bioresource Nucleus) (V.P., S.M., P.G., J.C.R.), Universidad de La Frontera, Temuco, 8330024 Chile; Departamento de Anatomía Patológica (J.C.R.), Escuela de Medicina, Pontificia Universidad Católica de Chile, Santiago de Chile, 8330024 Chile; and Advanced Center for Chronic Diseases (J.C.R.), Pontificia Universidad Católica de Chile, Santiago de Chile, 8330024 Chile.

Accumulated findings have demonstrated the presence of bidirectional interactions between progesterone receptor (PR) and the ErbB family of receptor tyrosine kinases signaling pathways in breast cancer. We previously revealed signal transducer and activator of transcription 3 (Stat3) as a nodal convergence point between said signaling pathways proving that Stat3 is activated by one of the ErbBs' ligands, heregulin (HRG)β1 via ErbB2 and through the co-option of PR as a signaling molecule. Here, we found that HRGβ1 induced Stat3 recruitment to the promoters of the progestin-regulated cell cycle modulators Bcl-XL and p21(CIP1) and also stimulated Stat3 binding to the mouse mammary tumor virus promoter, which carries consensus progesterone response elements. Interestingly, HRGβ1-activated Stat3 displayed differential functions on PR activity depending on the promoter bound. Indeed, Stat3 was required for PR binding in bcl-X, p21(CIP1), and c-myc promoters while exerting a PR coactivator function on the mouse mammary tumor virus promoter. Stat3 also proved to be necessary for HRGβ1-induced in vivo tumor growth. Our results endow Stat3 a novel function as a coregulator of HRGβ1-activated PR to promote breast cancer growth. These findings underscore the importance of understanding the complex interactions between PR and other regulatory factors, such as Stat3, that contribute to determine the context-dependent transcriptional actions of PR.
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http://dx.doi.org/10.1210/me.2015-1170DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5414679PMC
October 2015

Progesterone receptor activation downregulates GATA3 by transcriptional repression and increased protein turnover promoting breast tumor growth.

Breast Cancer Res 2014 Dec 6;16(6):491. Epub 2014 Dec 6.

Instituto de Biología y Medicina Experimental (IBYME), CONICET, Vuelta de Obligado 2490, Buenos Aires, 1428 ADN, Argentina.

Introduction: The transcription factor GATA3 is involved in mammary gland development and is crucial for the maintenance of the differentiated status of luminal epithelial cells. The role of GATA3 in breast cancer as a tumor suppressor has been established, although insights into the mechanism of GATA3 expression loss are still required.

Methods: Chromatin immunoprecipitation assays were conducted to study progestin modulation of recruitment of transcription factors to GATA3 promoter. We performed western blot and reverse RT-qPCR experiments to explore progestin regulation of GATA3 protein and mRNA expression respectively. Confocal microscopy and in vitro phosphorylation studies were conducted to examine progestin capacity to induce GATA3 serine phosphorylation in its 308 residue. GATA3 participation in progestin-induced breast cancer growth was addressed in in vitro proliferation and in vivo tumor growth experiments.

Results: In this study, we demonstrate that progestin-activated progesterone receptor (PR) reduces GATA3 expression through regulation at the transcriptional and post-translational levels in breast cancer cells. In the former mechanism, the histone methyltransferase enhancer of zeste homolog 2 is co-recruited with activated PR to a putative progesterone response element in the GATA3 proximal promoter, increasing H3K27me3 levels and inducing chromatin compaction, resulting in decreased GATA3 mRNA levels. This transcriptional regulation is coupled with increased GATA3 protein turnover through progestin-induced GATA3 phosphorylation at serine 308 followed by 26S proteasome-mediated degradation. Both molecular mechanisms converge to accomplish decreased GATA3 expression levels in breast cancer cells upon PR activation. In addition, we demonstrated that decreased GATA3 levels are required for progestin-induced upregulation of cyclin A2, which mediates the G1 to S phase transition of the cell cycle and was reported to be associated with poor prognosis in breast cancer. Finally, we showed that downregulation of GATA3 is required for progestin stimulation of both in vitro cell proliferation and in vivo tumor growth.

Conclusions: In the present study, we reveal that progestin-induced PR activation leads to loss of GATA3 expression in breast cancer cells through transcriptional and post-translational regulation. Importantly, we demonstrate that GATA3 downregulation is required for progestin-induced upregulation of cyclin A2 and for progestin-induced in vitro and in vivo breast cancer cell growth.
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http://dx.doi.org/10.1186/s13058-014-0491-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4303201PMC
December 2014

Progestin drives breast cancer growth by inducing p21(CIP1) expression through the assembly of a transcriptional complex among Stat3, progesterone receptor and ErbB-2.

Steroids 2013 Jun 21;78(6):559-67. Epub 2012 Nov 21.

Instituto de Biología y Medicina Experimental (IBYME), CONICET, Vuelta de Obligado 2490, Buenos Aires C1428ADN, Argentina.

Cell cycle regulator p21(CIP1) has controversial biological effects in breast cancer since in spite of its role as cell cycle inhibitor and promoter of cellular senescence, it also induces cell proliferation and chemoteraphy resistance. We here explored the molecular mechanisms involved in progestin regulation of p21(CIP1) expression. We also investigated the biological effects of p21(CIP1) in breast cancer cells. We found that the synthetic progestin medroxyprogesterone acetate (MPA) upregulates p21(CIP1) protein expression via c-Src, signal transducer and activator of transcription 3 (Stat3) and ErbB-2 phosphorylation. Notably, we also found that ErbB-2 nuclear function plays a key role in MPA-induction of p21(CIP1) expression. Interestingly, we determined that progestin drives p21(CIP1) transcriptional activation via a novel nonclassical transcriptional mechanism in which progesterone receptor is recruited along with Stat3 and ErbB-2 to a Stat3 binding site at p21(CIP1) promoter. Our findings revealed that ErbB-2 functions as a coactivator of Stat3 in progestin induction of p21(CIP1) transcriptional activation. Furthermore, we demonstrated that blockage of p21(CIP1) expression strongly inhibited in vitro and in vivo progestin-induced breast cancer cell proliferation. These results further support the hypothesis that according to cell context and type of stimulus, p21(CIP1) is capable of inducing cell cycle progression. Moreover, we provided evidence that Stat3 and nuclear ErbB-2 are key players in progestin-induced p21(CIP1) regulation.
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http://dx.doi.org/10.1016/j.steroids.2012.11.003DOI Listing
June 2013

Influence of conformationally restricted pyrimidines on the activity of 10-23 DNAzymes.

Bioorg Med Chem 2012 Apr 28;20(8):2581-6. Epub 2012 Feb 28.

INGEBI (CONICET), Vuelta de Obligado 2490-(1428), Buenos Aires, Argentina.

The catalytic core of a 10-23 DNAzyme was modified introducing conformationally restricted nucleosides such as (2'R)-, (2'S)-2'-deoxy-2'-C-methyluridine, (2'R)-, (2'S)-2'-deoxy-2'-C-methylcytidine, 2,2'-anhydrouridine and LNA-C, in one, two or three positions. Catalytic activities under pseudo first order conditions were compared at different Mg(2+) concentrations using a short RNA substrate. At low Mg(2+) concentrations, triple modified DNAzymes with similar kinetic performance to that displayed by the non-modified control were identified. In the search for a partial explanation of the obtained results, in silico studies were carried out in order to explore the conformational behavior of 2'-deoxy-2'-C-methylpyrimidines in the context of a loop structure, suggesting that at least partial flexibility is needed for the maintenance of activity. Finally, the modified 2'-C-methyl DNAzyme activity was tested assessing the inhibition of Stat3 expression and the decrease in cell proliferation using the human breast cancer cell line T47D.
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http://dx.doi.org/10.1016/j.bmc.2012.02.047DOI Listing
April 2012