Showing papers by "Mario Chiariello published in 2015"

Aptamer targeting EGFRvIII mutant hampers its constitutive autophosphorylation and affects migration, invasion and proliferation of glioblastoma cells

Abstract: Glioblastoma Multiforme (GBM) is the most common and aggressive human brain tumor, associated with very poor survival despite surgery, radiotherapy and chemotherapy.The epidermal growth factor receptor (EGFR) and the platelet-derived growth factor receptor β (PDGFRβ) are hallmarks in GBM with driving roles in tumor progression. In approximately half of the tumors with amplified EGFR, the EGFRvIII truncated extracellular mutant is detected. EGFRvIII does not bind ligands, is highly oncogenic and its expression confers resistance to EGFR tyrosine kinase inhibitors (TKIs). It has been demonstrated that EGFRvIII-dependent cancers may escape targeted therapy by developing dependence on PDGFRβ signaling, thus providing a strong rationale for combination therapy aimed at blocking both EGFRvIII and PDGFRβsignaling.We have recently generated two nuclease resistant RNA aptamers, CL4 and Gint4.T, as high affinity ligands and inhibitors of the human wild-type EGFR (EGFRwt) and PDGFRβ, respectively.Herein, by different approaches, we demonstrate that CL4 aptamer binds to the EGFRvIII mutant even though it lacks most of the extracellular domain. As a consequence of binding, the aptamer inhibits EGFRvIII autophosphorylation and downstream signaling pathways, thus affecting migration, invasion and proliferation of EGFRvIII-expressing GBM cell lines.Further, we show that targeting EGFRvIII by CL4, as well as by EGFR-TKIs, erlotinib and gefitinib, causes upregulation of PDGFRβ. Importantly, CL4 and gefitinib cooperate with the anti-PDGFRβ Gint4.T aptamer in inhibiting cell proliferation.The proposed aptamer-based strategy could have impact on targeted molecular cancer therapies and may result in progresses against GBMs.

FBXW7 and USP7 regulate CCDC6 turnover during the cell cycle and affect cancer drugs susceptibility in NSCLC

Abstract: // Francesco Morra 1,2,* , Chiara Luise 1,* , Francesco Merolla 1,3 , Ina Poser 4 , Roberta Visconti 1 , Gennaro Ilardi 3 , Simona Paladino 2 , Hiroyuki Inuzuka 5 , Gianluca Guggino 6 , Roberto Monaco 7 , David Colecchia 8 , Guglielmo Monaco 6 , Aniello Cerrato 1 , Mario Chiariello 8 , Krista Denning 9 , Pier Paolo Claudio 10 , Stefania Staibano 3 and Angela Celetti 1 1 Istituto per l’Endocrinologia e l’Oncologia Sperimentale “Gaetano Salvatore”, CNR, Napoli, Italy 2 Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Universita Federico II, Napoli, Italy 3 Dipartimento di Scienze Biomediche Avanzate, Universita Federico II, Napoli, Italy 4 Max Plank Institute, MPI-CBG Dresden, Germany 5 Harvard Medical School, Beth Israel Deaconess Medical Center, MA, USA 6 UOC Chirurgia Toracica, Azienda Ospedaliera di Rilievo Nazionale “A.Cardarelli”, Napoli, Italy 7 UOC Anatomia Patologica, Azienda Ospedaliera di Rilievo Nazionale “A.Cardarelli”, Napoli, Italy 8 Istituto Toscano Tumori, Core Research Laboratory, Siena, Italy 9 Department of Pathology, Joan C. Edwards Cancer Center, Huntington, WV, USA 10 Department of Biochemistry and Microbiology & Dept. of Surgery, Marshall University, Joan C. Edwards Cancer Center, Huntington, WV, USA * These authors have contributed equally to this work Correspondence to: Angela Celetti, email: // Keywords : CCDC6, FBXW7, USP7, mitotic kinases, cisplatinum Received : January 20, 2015 Accepted : March 03, 2015 Published : March 30, 2015 Abstract CCDC6 gene product is a pro-apoptotic protein substrate of ATM, whose loss or inactivation enhances tumour progression. In primary tumours, the impaired function of CCDC6 protein has been ascribed to CCDC6 rearrangements and to somatic mutations in several neoplasia. Recently, low levels of CCDC6 protein, in NSCLC, have been correlated with tumor prognosis. However, the mechanisms responsible for the variable levels of CCDC6 in primary tumors have not been described yet. We show that CCDC6 turnover is regulated in a cell cycle dependent manner. CCDC6 undergoes a cyclic variation in the phosphorylated status and in protein levels that peak at G2 and decrease in mitosis. The reduced stability of CCDC6 in the M phase is dependent on mitotic kinases and on degron motifs that are present in CCDC6 and direct the recruitment of CCDC6 to the FBXW7 E3 Ubl. The de-ubiquitinase enzyme USP7 appears responsible of the fine tuning of the CCDC6 stability, affecting cells behaviour and drug response. Thus, we propose that the amount of CCDC6 protein in primary tumors, as reported in lung, may depend on the impairment of the CCDC6 turnover due to altered protein-protein interaction and post-translational modifications and may be critical in optimizing personalized therapy.

MAPK15 mediates BCR-ABL1-induced autophagy and regulates oncogene-dependent cell proliferation and tumor formation

Abstract: A reciprocal translocation of the ABL1 gene to the BCR gene results in the expression of the oncogenic BCR-ABL1 fusion protein, which characterizes human chronic myeloid leukemia (CML), a myeloproliferative disorder considered invariably fatal until the introduction of the imatinib family of tyrosine kinase inhibitors (TKI). Nonetheless, insensitivity of CML stem cells to TKI treatment and intrinsic or acquired resistance are still frequent causes for disease persistence and blastic phase progression experienced in patients after initial successful therapies. Here, we investigated a possible role for the MAPK15/ERK8 kinase in BCR-ABL1-dependent autophagy, a key process for oncogene-induced leukemogenesis. In this context, we showed the ability of MAPK15 to physically recruit the oncogene to autophagic vesicles, confirming our hypothesis of a biologically relevant role for this MAP kinase in signal transduction by this oncogene. Indeed, by modeling BCR-ABL1 signaling in HeLa cells and taking advantage of a physiologically relevant model for human CML, i.e. K562 cells, we demonstrated that BCR-ABL1-induced autophagy is mediated by MAPK15 through its ability to interact with LC3-family proteins, in a LIR-dependent manner. Interestingly, we were also able to interfere with BCR-ABL1-induced autophagy by a pharmacological approach aimed at inhibiting MAPK15, opening the possibility of acting on this kinase to affect autophagy and diseases depending on this cellular function. Indeed, to support the feasibility of this approach, we demonstrated that depletion of endogenous MAPK15 expression inhibited BCR-ABL1-dependent cell proliferation, in vitro, and tumor formation, in vivo, therefore providing a novel "druggable" link between BCR-ABL1 and human CML.

Hybrid cholesterol-based nanocarriers containing phosphorescent Ir complexes: in vitro imaging on glioblastoma cell line

Abstract: Recently the use of phosphorescent heavy-metal complexes in bioimaging techniques has been a promising research field and has been attracted increasing interest. Among these, phosphorescent iridium(III) complexes have shown many photophysical characteristics that made them promising candidates for fluorescence probes. In this study an innovative copolymer consisting of cholesterol, a natural component of biological membranes, and the well-known biocompatible Polyethylene (PEG), has been synthesized. Cholesterol–PEG amphiphilic copolymer has been used to form novel nanocarriers characterized by the incorporation and/or linkage of the phosphorescent iridium(III) derivatives through covalent or non-covalent interactions. Finally the nanocarrier's surface has been functionalized with the peptide chlorotoxin (Cltx), a targeting agent selective for glioblastoma cells (U87MG). The so obtained targeted water soluble nanocarrier has been tested for in vitro imaging on the glioblastoma cell line and has shown no toxic effect on cells.