3D extracellular matrix derived model of alveolar rhabdomyosarcoma

INTRODUCTION: Rhabdomyosarcoma is the most common soft tissue sarcoma in childhood, among the subtypes the Alveolar (ARMS) is the more aggressive with a higher tendency to metastasize [1]. Integrins are a class of transmembrane adhesion molecules that mediate survival, differentiation, migration and differentiation [2]. Here we investigate the role of integrins in ARMS metastatic migration in an engineered 3D scaffold. METHODS: ARMS xenografts are obtained from subcutaneous injection of RH30 cells in immunodeficient mice. Composition of the ECM is determined by proteomic analysis. The main components of the ECM are used to enrich a 3D collagen scaffold cultured in a perfusion bioreactor. Cells are analyzed by qPCR for the expression of a panel of integrins. Presence of the protein is confirmed by flow cytometry immunofluorescence. MMPs expression is evaluated by zymography. RESULTS: Verified the expression of human and ARMS marker and typical tumor morphology in xenografts, they are processed for proteomic analysis. Proteomic data analysis is currently under investigation. Preliminary data culturing RH30 cells in 3D bioreactor show upregulation of ITG5 and CXCR4 receptor compared to 2D condition. Localization and quantification at protein level will be assessed respectively by immunofluorescence and cytofluorimetry. Expression of MMP-9 and MMP-2 has been assessed by zymography comparing the expression of these MMPs in 2D vs 3D bioreactor and RH30 isolated from the xenograft. DISCUSSION & CONCLUSIONS: Preliminary data on ITG expression show that in 3D scaffold the expression of ITG5 and CXCR4 is upregulated. In parallel the active form of MMP-2 is more present in 3D models compared to 2D. Other groups reported a mechanical interaction between ITG5 and MMP-2 [3]. This interaction will be studied in a more representative engineered 3D scaffold to shed light on the complex interaction between ECM and metastatic progression

In Vitro Modeling of Tumor-Immune System Interaction.

Immunotherapy has emerged during the past two decades as an innovative and successful form of cancer treatment. However, frequently, mechanisms of actions are still unclear, predictive markers are insufficiently characterized, and preclinical assays for innovative treatments are poorly reliable. In this context, the analysis of tumor/immune system interaction plays key roles, but may be unreliably mirrored by in vivo experimental models and standard bidimensional culture systems. Tridimensional cultures of tumor cells have been developed to bridge the gap between in vitro and in vivo systems. Interestingly, defined aspects of the interaction of cells from adaptive and innate immune systems and tumor cells may also be mirrored by 3D cultures. Here we review in vitro models of cancer/immune cell interaction and we propose that updated technologies might help develop innovative treatments, identify biologicals of potential clinical relevance, and select patients eligible for immunotherapy treatments

Mechanically defined microenvironment promotes stabilization of microvasculature, which correlates with the enrichment of a novel Piezo-1+ population of circulating CD11b+/CD115+ monocytes

Vascularization is a critical step in the restoration of cellular homeostasis. Several strategies including localized growth factor delivery, endothelial progenitor cells, genetically engineered cells, gene therapy, and prevascularized implants have been explored to promote revascularization. But, long-term stabilization of newly induced vessels remains a challenge. It has been shown that fibroblasts and mesenchymal stem cells can stabilize newly induced vessels. However, whether an injected biomaterial alone can serve as an instructive environment for angiogenesis remains to be elucidated. It is reported here that appropriate vascular branching, and long-term stabilization can be promoted simply by implanting a hydrogel with stiffness matching that of fibrin clot. A unique subpopulation of circulating CD11b+ myeloid and CD11b+ /CD115+ monocytes that express the stretch activated cation channel Piezo-1, which is enriched prominently in the clot-like hydrogel, is identified. These findings offer evidence for a mechanobiology paradigm in angiogenesis involving an interplay between mechanosensitive circulating cells and mechanics of tissue microenvironment

Identification of TPM2 and CNN1 as Novel Prognostic Markers in Functionally Characterized Human Colon Cancer-Associated Stromal Cells

Stromal infiltration is associated with poor prognosis in human colon cancers. However, the high heterogeneity of human tumor-associated stromal cells (TASCs) hampers a clear identification of specific markers of prognostic relevance. To address these issues, we established short-term cultures of TASCs and matched healthy mucosa-associated stromal cells (MASCs) from human primary colon cancers and, upon characterization of their phenotypic and functional profiles in vitro and in vivo, we identified differentially expressed markers by proteomic analysis and evaluated their prognostic significance. TASCs were characterized by higher proliferation and differentiation potential, and enhanced expression of mesenchymal stem cell markers, as compared to MASCs. TASC triggered epithelial-mesenchymal transition (EMT) in tumor cells in vitro and promoted their metastatic spread in vivo, as assessed in an orthotopic mouse model. Proteomic analysis of matched TASCs and MASCs identified a panel of markers preferentially expressed in TASCs. The expression of genes encoding two of them, calponin 1 (CNN1) and tropomyosin beta chain isoform 2 (TPM2), was significantly associated with poor outcome in independent databases and outperformed the prognostic significance of currently proposed TASC markers. The newly identified markers may improve prognostication of primary colon cancers and identification of patients at risk

VEGF dose regulates vascular stabilization through Semaphorin3A and the Neuropilin-1+ monocyte/TGF-β1 paracrine axis

VEGF is widely investigated for therapeutic angiogenesis, but while short-term delivery is desirable for safety, it is insufficient for new vessel persistence, jeopardizing efficacy. Here, we investigated whether and how VEGF dose regulates nascent vessel stabilization, to identify novel therapeutic targets. Monoclonal populations of transduced myoblasts were used to homogeneously express specific VEGF doses in SCID mouse muscles. VEGF was abrogated after 10 and 17 days by Aflibercept treatment. Vascular stabilization was fastest with low VEGF, but delayed or prevented by higher doses, without affecting pericyte coverage. Rather, VEGF dose-dependently inhibited endothelial Semaphorin3A expression, thereby impairing recruitment of Neuropilin-1-expressing monocytes (NEM), TGF-β1 production and endothelial SMAD2/3 activation. TGF-β1 further initiated a feedback loop stimulating endothelial Semaphorin3A expression, thereby amplifying the stabilizing signals. Blocking experiments showed that NEM recruitment required endogenous Semaphorin3A and that TGF-β1 was necessary to start the Semaphorin3A/NEM axis. Conversely, Semaphorin3A treatment promoted NEM recruitment and vessel stabilization despite high VEGF doses or transient adenoviral delivery. Therefore, VEGF inhibits the endothelial Semaphorin3A/NEM/TGF-β1 paracrine axis and Semaphorin3A treatment accelerates stabilization of VEGF-induced angiogenesis

EphrinB2/EphB4 signaling regulates non-sprouting angiogenesis by VEGF

Vascular endothelial growth factor (VEGF) is the master regulator of angiogenesis, whose best-understood mechanism is sprouting. However, therapeutic VEGF delivery to ischemic muscle induces angiogenesis by the alternative process of intussusception, or vascular splitting, whose molecular regulation is essentially unknown. Here, we identify ephrinB2/EphB4 signaling as a key regulator of intussusceptive angiogenesis and its outcome under therapeutically relevant conditions. EphB4 signaling fine-tunes the degree of endothelial proliferation induced by specific VEGF doses during the initial stage of circumferential enlargement of vessels, thereby limiting their size and subsequently enabling successful splitting into normal capillary networks. Mechanistically, EphB4 neither inhibits VEGF-R2 activation by VEGF nor its internalization, but it modulates VEGF-R2 downstream signaling through phospho-ERK1/2.; In vivo; inhibitor experiments show that ERK1/2 activity is required for EphB4 regulation of VEGF-induced intussusceptive angiogenesis. Lastly, after clinically relevant VEGF gene delivery with adenoviral vectors, pharmacological stimulation of EphB4 normalizes dysfunctional vascular growth in both normoxic and ischemic muscle. These results identify EphB4 as a druggable target to modulate the outcome of VEGF gene delivery and support further investigation of its therapeutic potential

TIA-1 Cytotoxic Granule-Associated RNA Binding Protein Improves the Prognostic Performance of CD8 in Mismatch Repair-Proficient Colorectal Cancer

Evidence suggests a confounding effect of mismatch repair (MMR) status on immune response in colorectal cancer. The identification of innate and adaptive immune cells, that can complement the established prognostic effect of CD8 in MMR-proficient colorectal cancers patients, representing 85% of all cases, has not been performed

Functional validation of cancer stem cell markers in primary human colorectal cancer and established cell lines

In an increasing number of cancers, CSCs have been defined on the basis of the self-renewal and tumor initiation capacity by functional assays. It has been also suggested that CSC populations might be responsible for chemo- and radio-therapy resistance within tumors and ultimately for the post-therapeutic tumor recurrence. The identification of markers identifying CSC is fundamental for the validation of the CSC paradigm and for the development of new CSC-specific drugs and novel therapeutic approach. CD133, CD44 and CD166 have been proposed as putative CSC markers in CRC. These findings have opened the field for an extensive validation of the markers and their use for the development of specific anti-CSC therapy. In this work, I addressed a) the prognostic relevance of the expression of CSC surface markers in CRC clinical specimens, b) the “in vivo” tumorigenicity of primary CRC derived cells, as related to their expression of putative CSC surface markers, c) the possibility of using cells derived from established CRC cell lines expressing CSC surface markers as CSC cellular model, and finally d) the development of innovative culture models of potential relevance for the screening of anti CRC compounds. I have analyzed the surface markers expression in correlation with stem cell-like functional features, but no consistent results was found confirming stemness property associated with expression of those markers. These results obviously question the validity of putative surface CRC-SC markers. Taken together these data might suggest that their expression and CSC functional features might be associated with some degree of plasticity, potentially related to tumor microenvironmental characteristics being lost in conventionally cultured tumor cell lines and in primary tumor derived cell suspensions. Based on this background I have investigated the possibility to perform 3D culture of CRC cell lines to assess whether these systems might provide useful insights for the interpretation of our data. My findings clearly document the plasticity of gene expression profiles of cultured CRC cells depending on their three-dimensional architectures. Most importantly, I demonstrate that major gene expression modulation events only occur when culture in 3D spheroids is associated with ischemia and necrosis. I also showed that the gene expression of putative CSC markers increases with the occurrence of ischemia and necrosis in the core of a 3D spheroid