Giovanna Nappo

University of Naples Federico II, Napoli, Campania, Italy

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Publications (6)27.36 Total impact

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    ABSTRACT: Metastasis, also called secondary neoplastic disease, is a tumour newly formed in a site different from that of origin, as a consequence of cancer progression and dissemination largely through blood and lymphatic vessels. The ability to form metastases is the main property that distinguishes malignant from benign tumours. Treatments for metastatic cancer are similar in practice to those for primary tumours, but such treatments are mostly palliative; indeed, almost all deaths caused by solid tumours occur in the metastatic phase. Increasing evidence supports the concept that therapies for primary tumours are inadequate to treat metastasis and can even promote formation of metastases, while exerting local growth control. Furthermore, recurrent tumours, which are denoted by increased aggressiveness and therapy resistance in comparison with the primary tumour, have an increased metastatic potential. Genetic modifications occurring during tumour progression lead to substantial differences between the primary and metastatic tumours. This emphasises the importance of designing novel therapies for metastasis. In the last decade, a number of studies have contributed to the understanding of the genetic rearrangements underlying the conversion of cancer cells into the metastasis founder cells. The present article aims at reviewing recent advances in metastasis research and attempts to discuss the reasons for which the therapeutic strategies against primary tumours may not satisfactorily address their metastatic counterparts.
    Current Medicinal Chemistry 08/2013; · 3.72 Impact Factor
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    ABSTRACT: Melanoma is resistant to most standard chemotherapeutics. We analysed the combined effect of doxorubicin and enzastaurin on cell death of four melanoma cell lines, namely G361, SK-MEL3, A375 and SAN. Enzastaurin IC50 was calculated by measure of growth inhibition with MTS assay and corresponded to 2 μM; the half maximal cytotoxicity of doxorubicin was obtained at 3μM dose. Evaluation of combination index showed synergism (CI>1) or additive effect (CI=1) with all melanoma cell lines, with enzastaurin doses >0.6 μM and doxorubicin doses > 1μM. Combination of the two drugs resulted in increase in caspase 3 and 8 activation, in comparison with activation by single agents. Caspase 8 activation was impaired by TNFR-1 blocking. Our results show doxorubicin stimulated production of TNFα, whereas enzastaurin stimulated TNFR-1 expression on plasmamembrane. The effect on TNFR-1 appeared to be mediated by PKCζ inhibition. Taken together, our findings suggest enzastaurin increases doxorubicin-induced apoptosis of melanoma by a mechanism involving, at least in part, activation of the TNF-α signal. This article is protected by copyright. All rights reserved.
    Pigment Cell & Melanoma Research 07/2013; · 5.84 Impact Factor
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    ABSTRACT: Melanoma is the most aggressive skin cancer; there is no cure in advanced stages. Identifying molecular participants in melanoma progression may provide useful diagnostic and therapeutic tools. FK506 binding protein 51 (FKBP51), an immunophilin with a relevant role in developmental stages, is highly expressed in melanoma and correlates with aggressiveness and therapy resistance. We hypothesized a role for FKBP51 in melanoma invasive behaviour. FKBP51 promoted activation of epithelial-to-mesenchymal transition (EMT) genes and improved melanoma cell migration and invasion. In addition, FKBP51 induced some melanoma stem cell (MCSC) genes. Purified MCSCs expressed high EMT genes levels, suggesting that genetic programs of EMT and MCSCs overlap. Immunohistochemistry of samples from patients showed intense FKBP51 nuclear signal and cytoplasmic positivity for the stem cell marker nestin in extravasating melanoma cells and metastatic brains. In addition, FKBP51 targeting by small interfering RNA (siRNA) prevented the massive metastatic substitution of liver and lung in a mouse model of experimental metastasis. The present study provides evidence that the genetic programs of cancer stemness and invasiveness overlap in melanoma, and that FKBP51 plays a pivotal role in sustaining such a program.
    Cell Death & Disease 01/2013; 4:e578. · 6.04 Impact Factor
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    ABSTRACT: Objective. Stimuli activating vascular smooth muscle cell death can constrain the neointimal response to arterial damage and prevent vascular thickening. Conversely, endothelial cell death increases endothelial dysfunction and thrombosis risk. We investigated the combined effect of atorvastatin and TNF-α on vascular cell death. Methods and Results. Cell death was investigated in cultures of human aortic smooth muscle cells (VSMCs) and human umbilical vein endothelial cells (HUVECs). Atorvastatin downregulated NF-kB and enhanced JNK activity and cell death in VSMC cultured with TNF-α. In the absence of TNF-α, percentages (mean and StDev) of annexin V positive cells were 17.4±6.6%, 19.3±5.9%, 22.9±9.4% and 35.0±20.0 % with 0, 1, 3 and 10 µM atorvastatin, respectively. The cytotoxic effect of statin was significant at the highest dose of 10 µM (p=0.001). In the presence of TNF-α, percentages of annexin V positive cells were 27.1±10.6%, 34.2±8.5%, 37.4±14.6, and 54.1±20.0% with 0, 1, 3 and 10 µM atorvastatin, respectively. The cytotoxic effect of statin was significant at each dose used (p< 0.02 ), in the presence of TNF-α. The cell death sensitising effect of atorvastatin was apparently mediated by down modulation of PKCβ activity, because it was reproduced by the specific PKCβ inhibitor LY317615 and prevented by the PKC activator phorbol-12-myristate-13-acetate (PMA). This effect was cell context dependent because it was not observed in HUVECs. PKCβ was found to be constitutively active in VSMCs but not in HUVECs, thereby explaining the differential effect among the two cell types. Measurement of phosphoPKCβ protein levels in arterial specimens confirmed increased activation of this kinase in the smooth muscle layer, in comparison with endothelium. We show that PKCβ provides survival signals to vascular smooth muscle cells and not the endothelium. Conclusion. Our study suggests that atorvastatin enhances TNF-α - induced cell death in vascular smooth muscle-but not endothelial by a cell-context-dependent mechanism, involving PKCβ inhibition.
    Current pharmaceutical design 10/2012; · 4.41 Impact Factor
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    ABSTRACT: FK506 binding protein 51 (FKBP51) is an immunophilin physiologically expressed in lymphocytes. Very recently, aberrant expression of this protein was found in melanoma; FKBP51 expression correlates with melanoma aggressiveness and is maximal in metastatic lesions. FKBP51 promotes NF-κB activation and is involved in the resistance to genotoxic agents, including anthracyclines and ionizing radiation. FKBP51 is a cochaperone with peptidyl-prolyl isomerase activity that regulates several biological processes through protein-protein interaction. There is increasing evidence that FKBP51 hyperexpression is associated with cancer and this protein has a relevant role in sustaining cell growth, malignancy, and resistance to therapy. There is also evidence that FKBP ligands are potent anticancer agents, in addition to their immunosuppressant activity. In particular, rapamycin and its analogs have shown antitumor activity across a variety of human cancers in clinical trials. Although, classically, rapamycin actions are ascribed to inhibition of mTOR, recent studies indicate FKBP51 is also an important molecular determinant of the drug's anticancer activity. The aim of this article is to review the functions of FKBP51, especially in view of the recent findings that this protein is a potential oncogene when deregulated and a candidate target for signaling therapies against cancer.
    Current Medicinal Chemistry 11/2011; 18(35):5424-9. · 3.72 Impact Factor
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    ABSTRACT: Although considered promising for use in drug-eluting stents (DES), tacrolimus failed clinically. Tacrolimus inhibits growth factor production but can also act as a growth factor on vascular smooth muscle cells (VSMC). This unexpected proliferative stimulus could reverse the beneficial effects of the drug on restenosis. We hypothesized that tacrolimus' association with statins, which lower cholesterol and impair cell proliferation, could restore tacrolimus' beneficial effect by abrogating the aberrant proliferative stimulus. Additionally, since maintenance of endothelial function represents a challenge for new-generation DES, we investigated the combined effect of tacrolimus and atorvastatin on endothelial cells. Human VSMC and umbilical vein endothelial cells (HUVEC) were incubated with 100 nM tacrolimus and increasing doses of atorvastatin (0-3.0 μM). Atorvastatin plus tacrolimus dose-dependently inhibited VSMC proliferation. The percentage of cells incorporating 5-bromo-2'-deoxyuridine (BrdU) in their DNA was 49 ± 14% under basal conditions, 62 ± 15% (P = 0.01) with tacrolimus, 40 ± 22% with 3 μM atorvastatin, and 30 ± 7% (P < 0.05) with 3 μM atorvastatin plus tacrolimus. Atorvastatin downregulated β-catenin, Erk1 and Erk2, and cyclin B in tacrolimus-stimulated VSMC. In contrast, atorvastatin plus tacrolimus did not affect proliferation of endothelial cells. The percentage of HUVEC incorporating BrdU in their DNA was 47 ± 8% under basal conditions, 58 ± 6% (P = 0.01) with tacrolimus, 45 ± 4% with 3 μM atorvastatin, and 49 ± 1% with 3 μM atorvastatin plus tacrolimus. Both agents stimulated endoglin production by HUVEC. Taken together, these results suggest that, when combined with tacrolimus, atorvastatin exerts a dose-dependent antiproliferative effect on VSMC. In contrast, atorvastatin acts in concert with tacrolimus in HUVEC to stimulate production of endoglin, a factor that has an important role in endothelial repair. Our study supports the conclusion that prevention of postcoronary in-stent restenosis and late thrombosis may benefit of concomitant association of tacrolimus and high doses of atorvastatin.
    AJP Heart and Circulatory Physiology 11/2011; 302(1):H135-42. · 3.63 Impact Factor