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Perego P.,Molecular Pharmacology Unit | Robert J.,French Institute of Health and Medical Research
Cancer Chemotherapy and Pharmacology | Year: 2016

Oxaliplatin is a third-generation platinum compound approved for clinical use relatively recently as compared to other drugs of the same class. Its main cellular target is DNA, where similarly to cisplatin and carboplatin it forms cross-links. However, due to a unique indication for colorectal cancer, synergistic interaction with fluoropyrimidines and peculiar toxicity profile, oxaliplatin is different from those compounds. Multiple lines of evidence indicate differences in transport and metabolism, consequences of DNA platination, as well as DNA repair and transduction of DNA damage. Here, we explore the preclinical features that may explain the unique properties of oxaliplatin in the clinics. Among them, the capability to accumulate in tumor cells via organic cation transporters, to kill KRAS mutant cells and to activate immunogenic cell death appears helpful to explain in part its clinical behavior. The continuous investigation of the molecular pharmacology of oxaliplatin is expected to provide clues to the definitions of predictors of drug activity and toxicity to translate to the clinical setting. © 2015 Springer-Verlag Berlin Heidelberg. Source

Caccia D.,Proteomics Laboratory | Micciche F.,Proteomics Laboratory | Cassinelli G.,Molecular Pharmacology Unit | Mondellini P.,Proteomics Laboratory | And 2 more authors.
Molecular Cancer | Year: 2010

Background: TPC-1 is a papillary thyroid carcinoma (PTC)-derived cell line that spontaneously expresses the oncogene RET/PTC1. TPC-1 treated with the RET/PTC1 inhibitor RPI-1 displayed a cytostatic and reversible inhibition of cell proliferation and a strong activation of focal adhesion kinase (FAK). As dasatinib inhibition of Src results in reduction of FAK activation, we evaluated the effects of TPC-1 treatment with dasatinib in combination with RPI-1.Results: Dasatinib (100 nM) strongly reduced TPC-1 proliferation and induced marked changes in TPC-1 morphology. Cells appeared smaller and more contracted, with decreased cell spreading, due to the inhibition of phosphorylation of important cytoskeletal proteins (p130CAS, Crk, and paxillin) by dasatinib. The combination of RPI-1 with dasatinib demonstrated enhanced effects on cell proliferation (more than 80% reduction) and on the phosphotyrosine protein profile. In particular, RPI-1 reduced the phosphorylation of RET, MET, DCDB2, CTND1, and PLCγ, while dasatinib acted on the phosphorylation of EGFR, EPHA2, and DOK1. Moreover, dasatinib completely abrogated the phosphorylation of FAK at all tyrosine sites (Y576, Y577, Y861, Y925) with the exception of the autoactivation site (Y397). Notably, the pharmacological treatments induced an overexpression of integrin β1 (ITB1) that was correlated with a mild enhancement in phosphorylation of ERK1/2 and STAT3, known for their roles in prevention of apoptosis and in increase of proliferation and survival. A reduction in Akt, p38 and JNK1/2 activation was observed.Conclusions: All data demonstrate that the combination of the two drugs effectively reduced cell proliferation (by more than 80%), significantly decreased Tyr phosphorylation of almost all phosphorylable proteins, and altered the morphology of the cells, supporting high cytostatic effects. Following the combined treatment, cell survival pathways appeared to be mediated by STAT3 and ERK activities resulting from integrin clustering and FAK autophosphorylation. EphA2 may also contribute, at least in part, to integrin and FAK activation. In conclusion, these data implicate ITB1 and EphA2 as promising therapeutic targets in PTC. © 2010 Caccia et al; licensee BioMed Central Ltd. Source

Faversani A.,Fondazione IRCCS Ca Granda ospedale Maggiore Policlinico | Vaira V.,Fondazione IRCCS Ca Granda ospedale Maggiore Policlinico | Moro G.P.,Breast Unit | Tosi D.,University of Milan | And 6 more authors.
Breast Cancer Research | Year: 2014

Introduction: The molecular determinants of breast cancer resistance to first-line anthracycline-containing chemotherapy are unknown.Methods: We examined the response to doxorubicin of organotypic cultures of primary human breast tumors ex vivo with respect to cell proliferation, DNA damage and modulation of apoptosis. Samples were analyzed for genome-wide modulation of cell death pathways, differential activation of p53, and the role of survivin family molecules in drug resistance. Rational drug combination regimens were explored by high-throughput screening, and validated in model breast cancer cell types.Results: Doxorubicin treatment segregated organotypic human breast tumors into distinct Responder or Non Responder groups, characterized by differential proliferative index, stabilization of p53, and induction of apoptosis. Conversely, tumor histotype, hormone receptor or human epidermal growth factor receptor-2 (HER2) status did not influence chemotherapy sensitivity. Global analysis of cell death pathways identified survivin and its alternatively spliced form, survivin-ΔEx3 as uniquely overexpressed in Non Responder breast tumors. Forced expression of survivin-ΔEx3 preserved cell viability and prevented doxorubicin-induced apoptosis in breast cancer cell types. High-throughput pharmacologic targeting of survivin family proteins with a small-molecule survivin suppressant currently in the clinic (YM155) selectively potentiated the effect of doxorubicin, but not other chemotherapeutics in breast cancer cell types, and induced tumor cell apoptosis.Conclusions: Survivin family proteins are novel effectors of doxorubicin resistance in chemotherapy-naive breast cancer. The incorporation of survivin antagonist(s) in anthracycline-containing regimens may have improved clinical activity in these patients. © 2014 Faversani et al.; licensee BioMed Central Ltd. Source

Arrighetti N.,Molecular Pharmacology Unit | Corno C.,Molecular Pharmacology Unit | Gatti L.,Molecular Pharmacology Unit
Critical Reviews in Oncogenesis | Year: 2015

The treatment of tumor cells with HDAC inhibitors (HDACi) induces a range of effects including apoptosis, cell cycle arrest, differentiation and senescence, modulation of immune response, and altered angiogenesis. The single-agent activities of several HDACi have been tested in preclinical and clinical studies and are currently the subject of ongoing clinical trials. Although HDACi have been shown to be effective as a single agent against a defined subset of hematological tumors, less convincing results have been found in the treatment of solid tumors. Since current clinical trials of single-agent HDACi showed limited efficacy, in this review we focus on drug combinations including HDACi with conventional chemotherapeutic agents and novel targeted agents. Particular emphasis has been devoted to combinations effective in solid tumors and to combinations between HDACi and immunotherapies. An outline of novel combination strategies, including a new generation of more potent and specific HDACi (e.g., compounds with adamantine and noradamantane as scaffolds) as well as chemical hybrid molecules, has been provided. The paradoxical role of HDACs as tumor suppressors in developing tumors and as therapeutic targets in established neoplasms has also been considered. © 2015 by Begell House, Inc. Source

Pennati M.,Molecular Pharmacology Unit | Lopergolo A.,Molecular Pharmacology Unit | Profumo V.,Molecular Pharmacology Unit | De Cesare M.,Molecular Pharmacology Unit | And 5 more authors.
Biochemical Pharmacology | Year: 2014

Compelling evidence suggests that epithelial-to-mesenchymal transition is involved in the resistance of human cancer cells to chemotherapy. We previously reported that the expression of miR-205, a miRNA down-regulated in prostate cancer, is further repressed in prostate cancer cells undergoing epithelial-to-mesenchymal transition, suggesting a possible involvement of the miRNA in the acquisition of the chemoresistant phenotype. In the present study, we show that miR-205 replacement in castration-resistant mesenchymal prostate cancer cells caused an enhancement of cisplatin cytotoxic activity in vitro and in vivo, as a consequence of autophagy impairment. Specifically, the constraints on the autophagic flux were associated to the miRNA-dependent down-regulation of the lysosome-associated proteins RAB27A and LAMP3. These findings suggest that miR-205-mediated impairment of the autophagic pathway may interfere with the detoxifying capabilities of prostate cancer cells in their attempt to cope with cisplatin-induced detrimental effects. Overall, our data indicate that (i) loss of miR-205 may indeed contribute to acquire mesenchymal tracts and concomitantly establish a permissive autophagic milieu that confers a chemotherapy resistant phenotype to prostate cancer cells, and (ii) strategies aimed at restoring miR-205 expression levels may represent a successful approach to overcome resistance of prostate cancer to platinum compounds. © 2013 Elsevier Inc. Source

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