BioFlag Ltd.

Cagliari, Italy

BioFlag Ltd.

Cagliari, Italy

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Corno D.,Neural Stem Cell Biology Unit | Pala M.,Bioflag Ltd | Cominelli M.,University of Brescia | Cipelletti B.,Neural Stem Cell Biology Unit | And 12 more authors.
Cancer Discovery | Year: 2012

Medulloblastoma arises from mutations occurring in stem/progenitor cells located in restricted hindbrain territories. Here we report that the mouse postnatal ventricular zone lining the IV ventricle also harbors bona fide stem cells that, remarkably, share the same molecular profile with cerebellar white matter-derived neural stem cells (NSC). To identify novel molecular mediators involved in medulloblastomagenesis, we compared these distinct postnatal hindbrain-derived NSC populations, which are potentially tumor initiating, with murine compound Ptch/p53 mutant medulloblastoma cancer stem cells (CSC) that faithfully phenocopy the different variants of human medulloblastoma in vivo. Transcriptome analysis of both hindbrain NSCs and medulloblastoma CSCs resulted in the generation of well-defined gene signatures, each reminiscent of a specific human medulloblastoma molecular subclass. Most interestingly, medulloblastoma CSCs upregulated developmentally related genes, such as Ebfs, that were shown to be highly expressed in human medulloblastomas and play a pivotal role in experimental medulloblastomagenesis. These data indicate that gene expression analysis of medulloblastoma CSCs holds great promise not only for understanding functional differences between distinct CSC populations but also for identifying meaningful signatures that might stratify medulloblastoma patients beyond histopathologic staging. SIGNIFICANCE: The functional and molecular comparison between the cell progenitor lineages from which medulloblastoma is thought to arise and medulloblastoma CSCs might lead to the identification of novel, potentially relevant mediators of medulloblastomagenesis. Our findings provide a rationale for the exploitation of mouse CSCs as a valuable preclinical model for human medulloblastoma, both for the definition of CSC-associated gene signatures with predictive mean and for the identification of therapeutically targetable genes. © 2012 American Association for Cancer Research.

Magri L.,San Raffaele Scientific Institute | Magri L.,Vita-Salute San Raffaele University | Cambiaghi M.,San Raffaele Scientific Institute | Cominelli M.,University of Brescia | And 11 more authors.
Cell Stem Cell | Year: 2011

Tuberous Sclerosis Complex (TSC) is a multisystem genetic disorder characterized by hamartomatous neurological lesions that exhibit abnormal cell proliferation and differentiation. Hyperactivation of mTOR pathway by mutations in either the Tsc1 or Tsc2 gene underlies TSC pathogenesis, but involvement of specific neural cell populations in the formation of TSC-associated neurological lesions remains unclear. We deleted Tsc1 in Emx1-expressing embryonic telencephalic neural stem cells (NSCs) and found that mutant mice faithfully recapitulated TSC neuropathological lesions, such as cortical lamination defects and subependymal nodules (SENs). These alterations were caused by enhanced generation of SVZ neural progeny, followed by their premature differentiation and impaired maturation during both embryonic and postnatal development. Notably, mTORC1-dependent Akt inhibition and STAT3 activation were involved in the reduced self-renewal and earlier neuronal and astroglial differentiation of mutant NSCs. Thus, finely tuned mTOR activation in embryonic NSCs may be critical to prevent development of TSC-associated brain lesions. © 2011 Elsevier Inc.

Mazzoleni S.,San Raffaele Scientific Institute | Mazzoleni S.,Vita-Salute San Raffaele University | Politi L.S.,San Raffaele Scientific Institute | Pala M.,Bio flag Ltd. | And 8 more authors.
Cancer Research | Year: 2010

Epidermal growth factor receptor (EGFR) is a known diagnostic and, although controversial, prognostic marker of human glioblastoma multiforme (GBM). However, its functional role and biological significance in GBM remain elusive. Here, we show that multiple GBM cell subpopulations could be purified from the specimens of patients with GBM and from cancer stem cell (CSC) lines based on the expression of EGFR and of other putative CSC markers. All these subpopulations are molecularly and functionally distinct, are tumorigenic, and need to express EGFR to promote experimental tumorigenesis. Among them, EGFRexpressing tumor-initiating cells (TIC) display the most malignant functional and molecular phenotype. Accordingly, modulation of EGFR expression by gain-of-function and loss-of-function strategies in GBM CSC lines enhances and reduces their tumorigenic ability, respectively, suggesting that EGFR plays a fundamental role in gliomagenesis. These findings open up the possibility of new therapeutically relevant scenarios, as the presence of functionally heterogeneous EGFRpos and EGFRneg TIC subpopulations within the same tumor might affect clinical response to treatment. ©2010 AACR.

Ranzani M.,San Raffaele Scientific Institute | Cesana D.,San Raffaele Scientific Institute | Bartholomae C.C.,National Center for Tumor Diseases | Sanvito F.,San Raffaele Scientific Institute | And 15 more authors.
Nature Methods | Year: 2013

Transposons and γ-retroviruses have been efficiently used as insertional mutagens in different tissues to identify molecular culprits of cancer. However, these systems are characterized by recurring integrations that accumulate in tumor cells and that hamper the identification of early cancer-driving events among bystander and progression-related events. We developed an insertional mutagenesis platform based on lentiviral vectors (LVVs) by which we could efficiently induce hepatocellular carcinoma (HCC) in three different mouse models. By virtue of the LVV's replication-deficient nature and broad genome-wide integration pattern, LVV-based insertional mutagenesis allowed identification of four previously unknown liver cancer-associated genes from a limited number of integrations. We validated the oncogenic potential of all the identified genes in vivo, with different levels of penetrance. The newly identified genes are likely to play a role in human cancer because they are upregulated, amplified and/or deleted in human HCCs and can predict clinical outcomes of patients. © 2013 Nature America, Inc. All rights reserved.

Mazzoleni S.,Neural Stem Cell Biology Unit | Jachetti E.,Gene Therapy and Biolmmunotherapy of Cancer | Jachetti E.,Cellular Immunology Unit | Morosini S.,Neural Stem Cell Biology Unit | And 9 more authors.
Stem Cells Translational Medicine | Year: 2013

The relevant social and economic impact of prostate adenocarcinoma, one of the leading causes of death in men, urges critical improvements in knowledge of the pathogenesis and cure of this disease. These can also be achieved by implementing in vitro and in vivo preclinical models by taking advantage of prostate cancer stem cells (PCSCs). The best-characterized mouse model of prostate cancer is the transgenic adenocarcinoma of the mouse prostate (TRAMP) model. TRAMP mice develop a progressive lesion called prostatic intraepithelial neoplasia that evolves into adenocarcinoma (AD) between 24 and 30 weeks of age. ADs often metastasize to lymph nodes, lung, bones, and kidneys. Eventually, approximately 5% of the mice develop an androgen-independent neuroendocrine adenocarcinoma. Here we report the establishment of long-term self-renewing PCSC lines from the different stages of TRAMP progression by application of the neurosphere assay. Stagespecific prostate cell lines were endowed with the critical features expected from malignant bona fide cancer stem cells, namely, self-renewal, multipotency, and tumorigenicity. Notably, transcriptome analysis of stage-specific PCSCs resulted in the generation of well-defined, meaningful gene signatures, which identify distinct stages of human tumor progression. As such, TRAMP-derived PCSCs represent a novel and valuable preclinical model for elucidating the pathogenetic mechanisms leading to prostate adenocarcinoma and for the identification of molecular mediators to be pursued as therapeutic targets. © AlphaMed Press 2013.

PubMed | University of Perugia, National Research Council Italy, Instituto Of Ricovero E Cura A Carattere Scientifico San Raffaele, BioFlag Ltd. and San Raffaele Telethon Institute for Gene Therapy
Type: | Journal: Stem cells translational medicine | Year: 2016

: Allogeneic fetal-derived human neural stem cells (hfNSCs) that are under clinical evaluation for several neurodegenerative diseases display a favorable safety profile, but require immunosuppression upon transplantation in patients. Neural progenitors derived from patient-specific induced pluripotent stem cells (iPSCs) may be relevant for autologous ex vivo gene-therapy applications to treat genetic diseases with unmet medical need. In this scenario, obtaining iPSC-derived neural stem cells (NSCs) showing a reliable NSC signature is mandatory. Here, we generated human iPSC (hiPSC) clones via reprogramming of skin fibroblasts derived from normal donors and patients affected by metachromatic leukodystrophy (MLD), a fatal neurodegenerative lysosomal storage disease caused by genetic defects of the arylsulfatase A (ARSA) enzyme. We differentiated hiPSCs into NSCs (hiPS-NSCs) sharing molecular, phenotypic, and functional identity with hfNSCs, which we used as a gold standard in a side-by-side comparison when validating the phenotype of hiPS-NSCs and predicting their performance after intracerebral transplantation. Using lentiviral vectors, we efficiently transduced MLD hiPSCs, achieving supraphysiological ARSA activity that further increased upon neural differentiation. Intracerebral transplantation of hiPS-NSCs into neonatal and adult immunodeficient MLD mice stably restored ARSA activity in the whole central nervous system. Importantly, we observed a significant decrease of sulfatide storage when ARSA-overexpressing cells were used, with a clear advantage in those mice receiving neonatal as compared with adult intervention. Thus, we generated a renewable source of ARSA-overexpressing iPSC-derived bona fide hNSCs with improved features compared with clinically approved hfNSCs. Patient-specific ARSA-overexpressing hiPS-NSCs may be used in autologous ex vivo gene therapy protocols to provide long-lasting enzymatic supply in MLD-affected brains.The development of effective and safe neural stem cell-based therapies will depend on procedures that yield well-characterized and expandable autologous cell lines suitable for transplantation that could meet stringent safety criteria and bypass ethical concerns. This study showed that bona fide neural stem cells generated via somatic cell reprogramming from fibroblasts of patients affected by a genetic demyelinating lysosomal storage disease can be safely and efficiently engineered and may serve as a stable source of therapeutic enzyme to ameliorate pathology upon intracerebral transplantation and oligodendroglial differentiation in a relevant animal model of the disease.

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