Cumulative effects of electrode and dielectric surface modifications on pentacene-based transistors

Surface modifications of the dielectric and the metal of pentacene-based field effect transistors using self-assembled monolayer (SAM) were studied. First, a low interfacial trap density and pentacene 2D-growth were favored by the nonpolar and low surface energy of octadecyltrichlorosilane-based SAM. This treatment leaded to increased mobility up to 0.4 cm2 V−1 s−1 and no observable hysteresis on transfer curves. Second, reduced hole injection barrier and contact resistance were achieved by fluorinated thiols deposited on gold contacts resulting in an increased mobility up to 0.6 cm2 V−1 s−1. Finally, a high mobility of 2.6 cm2 V−1 s−1 was achieved by cumulative effects of both treatments

1693P Incidence of NTRK genes fusion in adult brain tumours: A prospective cohort of 140 patients with cerebral gliomas and brain metastases

International audienceBackground: ImmTAC molecules are TCR-anti-CD3 bispecific fusion proteins that can redirect polyclonal T cell activation against cancer cells. Tebentafusp, a gp100-directed ImmTAC, has demonstrated survival benefit in metastatic uveal melanoma 1. Here, patient-derived tumour organoids (TO) 2 and 3-dimensional multicellular melanospheres were evaluated as tumour models to study ImmTAC activity. Methods: 3D melanospheres were generated by low adherence culture of melanoma cell lines (MEL202, MEL624, 92.1, MP-41, A375, IGR-1, Mewo) and their melanin synthesis genes were quantified by qPCR. The capacity of ImmTAC to redirect T cells against melanospheres was assessed in vitro using IFNg and granzyme B Elispots in the presence or absence of commercially sourced IFNa2 or IFNb. Patient derived TO were generated by Tempus 2 and screened for HLA-A*02:01 and antigen positivity. ImmTAC-mediated killing of relevant TO was assessed by 3D high content imaging. Results: Melanospheres formed from all melanoma cell lines tested, and upregulated melanin synthesis genes including PMEL, MITF, and MLANA. This translated into visible but heterogenous melanin expression. ImmTAC were capable of redirecting T cells against cells from melanospheres to produce IFNg (EC 50 23 pM-4.8 nM) and granzyme B (EC 50 130 pM-1.4 nM). Treatment of 3D cultures with IFNa2 or IFNb for 48 hours augmented ImmTAC-mediated redirection of IFNg secretion by a mean of 4.42-fold. To further assess ImmTAC-mediated T cell redirection against more complex in vitro cultures, TO were derived from patient tumours and co-cultured with PBMC for 96 hours. In these settings, clinically relevant doses of ImmTAC redirected T cells to induce cell lysis of antigen positive TO (EC 50 29.3 pM). Conclusions: 3D melanospheres and TO may provide useful models to study tumour biology, heterogeneity, and ImmTAC activity. ImmTAC were capable of redirecting T cells against these in vitro tumour models, which will allow for better understanding of mechanism of action. 1

Silanization Strategies for Tailoring Peptide Functionalization on Silicon Surfaces: Implications for Enhancing Stem Cell Adhesion

International audienceBiomaterial surface engineering and the integration of cell-adhesive ligands are crucial in biological research and biotechnological applications. The interplay between cells and their microenvironment, influenced by chemical and physical cues, impacts cellular behavior. Surface modification of biomaterials profoundly affects cellular responses, especially at the cell-surface interface. This work focuses on enhancing cellular activities through material manipulation, emphasizing silanization for further functionalization with bioactive molecules such as RGD peptides to improve cell adhesion. The grafting of three distinct silanes onto silicon wafers using both spin coating and immersion methods was investigated. This study sheds light on the effects of different alkyl chain lengths and protecting groups on cellular behavior, providing valuable insights into optimizing silane-based self-assembled monolayers (SAMs) before peptide or protein grafting for the first time. Specifically, it challenges the common use of APTES molecules in this context. These findings advance our understanding of surface modification strategies, paving the way for tailoring biomaterial surfaces to modulate the cellular behavior for diverse biotechnological applications

Adrenomedullin Secreted by Melanoma Cells Promotes Melanoma Tumor Growth through Angiogenesis and Lymphangiogenesis

International audienceIntroduction: Metastatic melanoma is an aggressive tumor and can constitute a real therapeutic challenge despite the significant progress achieved with targeted therapies and immunotherapies, thus highlighting the need for the identification of new therapeutic targets. Adrenomedullin (AM) is a peptide with significant expression in multiple types of tumors and is multifunctional. AM impacts angiogenesis and tumor growth and binds to calcitonin receptor-like receptor/receptor activity-modifying protein 2 or 3 (CLR/RAMP2; CLR/RAMP3). Methods: In vitro and in vivo studies were performed to determine the functional role of AM in melanoma growth and tumor-associated angiogenesis and lymphangiogenesis. Results: In this study, AM and AM receptors were immunohistochemically localized in the tumoral compartment of melanoma tissue, suggesting that the AM system plays a role in melanoma growth. We used A375, SK-MEL-28, and MeWo cells, for which we demonstrate an expression of AM and its receptors; hypoxia induces the expression of AM in melanoma cells. The proliferation of A375 and SK-MEL-28 cells is decreased by anti-AM antibody (αAM) and anti-AMR antibodies (αAMR), supporting the fact that AM may function as a potent autocrine/paracrine growth factor for melanoma cells. Furthermore, migration and invasion of melanoma cells increased after treatment with AM and decreased after treatment with αAMR, thus indicating that melanoma cells are regulated by AM. Systemic administration of αAMR reduced neovascularization of in vivo Matrigel plugs containing melanoma cells, as demonstrated by reduced numbers of vessel structures, which suggests that AM is one of the melanoma cells-derived factors responsible for endothelial cell-like and pericyte recruitment in the construction of neovascularization. In vivo, αAMR therapy blocked angiogenesis and lymphangiogenesis and decreased proliferation in MeWo xenografts, thereby resulting in tumor regression. Histological examination of αAMR-treated tumors showed evidence of the disruption of tumor vascularity, with depletion of vascular endothelial cells and a significant decrease in lymphatic endothelial cells. Conclusions: The expression of AM by melanoma cells promotes tumor growth and neovascularization by supplying/amplifying signals for neoangiogenesis and lymphangiogenesis

Expression and Role of the Adrenomedullin System in Melanoma

International audienceThe present study performed a combination of In vitro and In vivo tests, examining the role of the AM system on the growth of melanoma cell lines and xenografts, respectively. Even though targeted medicines and immunotherapies have made tremendous progress, metastatic melanoma is an aggressive disease that can provide a serious therapeutic challenge. This underscores the necessity for the identification of new therapeutic targets. Adrenomedullin (AM) is a multifunctional peptide that is expressed significantly in many tumor types. By binding to calcitonin receptor-like receptor/receptor activity-modifying protein 2 or 3 (CLR/RAMP2; CLR/RAMP3), AM affects angiogenesis and tumor progression. In vitro and in vivo studies were performed to determine the functional role of AM in melanoma growth and tumor-associated angiogenesis and lymphangiogenesis. AM and AM receptors were immunohistochemically localized in the tumoral compartment of melanoma tissue, suggesting that the AM system plays a role in melanoma growth. We used A375, SK-MEL-28, and MeWo cells, for which we demonstrated an expression of AM and its receptors; hypoxia induces the expression of AM in melanoma cells. The proliferation of A375 and SK-MEL-28 cells is decreased by anti-AM antibody (aAM) and anti-AMR antibodies (AMR), supporting the fact that AM may function as a potent autocrine/paracrine growth factor for melanoma cells. Furthermore, migration and invasion of melanoma cells increased after treatment with AM and decreased after treatment with AMR, thus indicating that melanoma cells are regulated by AM. Reduced numbers of vessel structures showed that systemic administration of AMR decreased the neovascularization of in vivo Matrigel plugs containing melanoma cells. This suggests that AM is one of the factors derived from melanoma cells that is responsible for endothelial cell-like and pericyte recruitment in the construction of neovascularization. Tumor regression was achieved in vivo by AMR treatment, which inhibited angiogenesis and lymphangiogenesis and reduced proliferation in MeWo xenografts. Upon histological evaluation, tumors treated with AMR exhibited indications of disrupted tumor vascularity, including a notable reduction in lymphatic endothelial cells and a depletion of vascular endothelial cells. Finally, the representation of AM by melanoma cells promotes tumor growth and neovascularization by supplying/amplifying signals for neoangiogenesis and lymphangiogenesis

Role of the Tyrosine Phosphatase SHP-2 in Mediating Adrenomedullin Proangiogenic Activity in Solid Tumors

International audienceVE-cadherin is an essential adhesion molecule in endothelial adherens junctions, and the integrity of these complexes is thought to be regulated by VE-cadherin tyrosine phosphorylation. We have previously shown that adrenomedullin (AM) blockade correlates with elevated levels of phosphorylated VE-cadherin (pVE-cadherin Y731 ) in endothelial cells, associated with impaired barrier function and a persistent increase in vascular endothelial cell permeability. However, the mechanism underlying this effect is unknown. In this article, we demonstrate that the AM-mediated dephosphorylation of pVE-cadherin Y731 takes place through activation of the tyrosine phosphatase SHP-2, as judged by the rise of its active fraction phosphorylated at tyrosine 542 (pSHP-2 Y542 ) in HUVECs and glioblastoma-derived-endothelial cells. Both pre-incubation of HUVECs with SHP-2 inhibitors NSC-87877 and SHP099 and SHP-2 silencing hindered AM-induced dephosphorylation of pVE-cadherin Y731 in a dose dependent-manner, showing the role of SHP-2 in the regulation of endothelial cell contacts. Furthermore, SHP-2 inhibition impaired AM-induced HUVECs differentiation into cord-like structures in vitro and impeded AM-induced neovascularization in in vivo Matrigel plugs bioassays. Subcutaneously transplanted U87-glioma tumor xenograft mice treated with AM-receptors-blocking antibodies showed a decrease in pSHP-2 Y542 associated with VE-cadherin in nascent tumor vasculature when compared to control IgG-treated xenografts. Our findings show that AM acts on VE-cadherin dynamics through pSHP-2 Y542 to finally modulate cell-cell junctions in the angiogenesis process, thereby promoting a stable and functional tumor vasculature