Stefania Meschini - Academia.edu (original) (raw)

Papers by Stefania Meschini

Pharmacological Research, 1995

Cytotechnology, 1991

Morphological and ultrastructural modifications related to the cell injury and leading to cell de... more Morphological and ultrastructural modifications related to the cell injury and leading to cell death have been investigated by using different compounds. Data obtained by treating various cultured cells with a quinone (menadione), a polar solvent (NMF) and a bacterial protein toxin (toxin B fromClostridium difficile) are here reported Differences seem to exist between such injuries, but changes in plasma membrane structure, called surface blebbing phenomenon, represent a common feature which can be in any case detected. Our results also allow to hypothesize an important role of cytoskeleton in such a process.

International Journal of Cancer, 1998

The intracellular location of the MDR1 gene product, known as P-glycoprotein (P-gp), has been det... more The intracellular location of the MDR1 gene product, known as P-glycoprotein (P-gp), has been detected by flow cytometry in 3 stabilized human melanoma cell lines which had never undergone cytotoxic drug treatment and did not express P-gp on the plasma membrane. In addition, MDR1 mRNA expression was revealed by RT-PCR in the same cell lines. Immunofluorescence microscopy, performed by using the same 2 monoclonal antibodies (MM4.17 and MRK-16) as employed in the flow-cytometric analysis, revealed the presence of P-gp intracytoplasmically, in a well-defined perinuclear region. Double immunofluorescence labelling and immunoelectron microscopy strongly suggested the location of the transporter molecule in the Golgi apparatus. The same observations have been obtained on a primary culture from a metastasis of human melanoma. Analysis of the expression of another membrane transport protein, the multidrug-resistance-related protein (MRP1), showed that it was present in the cytoplasm of all the melanoma cell lines examined. MRP1 also showed Golgi-like localization. The study by laser scanning confocal microscopy on the intracellular localization of the anti-tumoral agent doxorubicin (DOX) during the drug-uptake and -efflux phases, indicated the Golgi apparatus as a preferential accumulation site for the anthracyclinic antibiotic. P-gp function modulators (verapamil and cyclosporin A) were able to modify DOX intracytoplasmic distribution and to increase drug intracellular concentration and cytotoxic effect in melanoma cells. On the contrary, MRP1 modulators (probenecid and genistein) did not significantly influence either DOX efflux and distribution or the sensitivity of melanoma cells to the cytotoxic drug.

Cancers

We investigated the chemosensitizing effect of electroporation (EP), which, using electrical puls... more We investigated the chemosensitizing effect of electroporation (EP), which, using electrical pulses, permeabilizes cancer cells to drugs. The study involved two human hypopharyngeal and tongue carcinoma cell lines. The surface and intracytoplasmic expression of P-gp were evaluated by flow cytometry, demonstrating that both lines were intrinsically resistant. After establishing the optimal dose of mitomycin C (MMC) to be used, in combination with EP, we showed, by both MTT assay and optical and electron scanning microscopy, the potentiating cytotoxic effect of EP with MMC compared to single treatments. Flow cytometry showed that the cytotoxicity of EP + MMC was due to the induction of apoptosis. In addition to verifying the release of cytochrome C in EP + MMC samples, we performed an expression analysis of caspase-3, caspase-9, Akt, pAkt, HMGB1, LC3I, LC3II, p62, Beclin1, and associated proteins with both apoptotic and autophagic phenomena. Our results were confirmed by two veterinar...

European Journal of Histochemistry

The conference aims to update participants on innovative microscopic equipment which, by correlat... more The conference aims to update participants on innovative microscopic equipment which, by correlating the various features of optical and electron microscopy, can maximize the potential applications of morphological and ultrastructural methods. The conference will address the limits of sample preparation, the optimization of image processing, and the critical analysis of experimental results with different materials.

Frontiers in Pharmacology

Journal of Experimental & Clinical Cancer Research

In the original publication of this article, [1] the affiliation for Katia Scotlandi needs to be ... more In the original publication of this article, [1] the affiliation for Katia Scotlandi needs to be revised, because the author prefers using its Italian name: Experimental Oncology Lab, Experimental Oncology Lab, CRS Development of Biomolecular Therapies, IRCCS Istituto Ortopedico Rizzoli. We apologize for any confusion this may have caused.

Chemistry and Physics of Lipids

Journal of experimental & clinical cancer research : CR, Jan 5, 2018

Presentation of the conference The 30 th Annual Conference of Italian Association of Cell Culture... more Presentation of the conference The 30 th Annual Conference of Italian Association of Cell Cultures (AICC) was held at Fondazione IRCCS Istituto Nazionale dei Tumori, in Milan, on November 27-28, 2017, with the Scientific Coordination of Claudia Chiodoni and Mario Paolo Colombo, from the same Institute. The conference was opened by Katia Scotlandi, President of the Italian Association of Cell Cultures. The main objective of the conference was to discuss the present knowledge on the role of immune cells in the tumor microenvironment, shaped by cells promoting tumor survival that could be reeducated to treat cancer. The meeting was organized in two days with 5 thematic sessions, an opening and a closing lecture, with national and international speakers. The organizers truly thank those who took part in the conference and made the Conference a success.

Oncotarget, 2014

Background: Cancer cells, including colorectal cancer ones (CRC), release high amounts of nanoves... more Background: Cancer cells, including colorectal cancer ones (CRC), release high amounts of nanovesicles (exosomes), delivering biochemical messages for paracrine or systemic crosstalk. Mesenchymal stromal cells (MSCs) have been shown to play contradicting roles in tumor progression. Results: CRC exosomes induce in cMSCs: i) atypical morphology, higher proliferation, migration and invasion; ii) formation of spheroids; iii) an acidic extracellular environment associated with iv) a plasma membrane redistribution of vacuolar H+-ATPase and increased expression of CEA. Colon cancer derived MSCs, which were isolated from tumor masses, produce umbilicated spheroids, a future frequently observed in the inner core of rapidly growing tumors and recapitulate the changes observed in normal colonic MSCs exposed to CRC exosomes. Materials and Methods: Tissue specific colonic (c)MSCs were exposed to primary or metastatic CRC exosomes and analysed by light and electron microscopy, proliferation in 2D and 3D cultures, migration and invasion assays, Western blot and confocal microscopy for vacuolar H+-ATPase expression. Conclusions: CRC exosomes are able to induce morphological and functional changes in colonic MSCs, which may favour tumor growth and its malignant progression. Our results suggest that exosomes are actively involved in cancer progression and that inhibiting tumor exosome release may represent a way to interfere with cancer.

Anticancer Research, 1992

Lonidamine (LND), a dichlorinated derivative of indazole-3-carboxylic acid, has proved to exert a... more Lonidamine (LND), a dichlorinated derivative of indazole-3-carboxylic acid, has proved to exert a powerful antiproliferative effect and to impair the energy metabolism of normal and neoplastic cells. A target effect of the drug on the cell membrane structure was hypothesized. Thus, in order to elucidate better the mechanism of action of LND, the drug effects on the cell surface as well as on main cytoskeletal elements, i.e. actin microfilaments, microtubules and intermediate filaments, were investigated. In particular, an immunocytochemical and ultrastructural study was performed using two different cell lines: epithelial squamous carcinoma (A431) and melanoma (M14) cells. Treatment with 0.8 mM LND for 8 hr induced a remarkable rearrangement of the F-actin molecules with the disappearance of the stress fibers. As far as microtubules are concerned, formation of perinuclear patches of tubulin were detected after LND treatment. Intermediate filaments appeared to be differently affected by LND in the two cell types. Such changes were detected as an early phenomenon and the extent of the effects observed was positively related to the cell surface alterations and to the loss of cell viability, suggesting that the cytoskeletal elements might represent an additional target in the mechanisms of cytotoxic action of LND.

European Journal of Cancer, Jan 9, 2012

Few articles in the literature have focused on electroporation as a strategy to reverse multidrug... more Few articles in the literature have focused on electroporation as a strategy to reverse multidrug resistance (MDR) of tumour cells and they are mostly limited to the improved efficacy of bleomycin. We tested the application of trains of biphasic pulses to cell suspensions and to murine xenografts as a strategy to increase the uptake of doxorubicin (DOX) and to enhance its cytotoxicity against chemoresistant cells. The human colon adenocarcinoma cell line LoVo DX, expressing MDR phenotype with high levels of P-glycoprotein (P-gp), has been used. The in vitro and in vivo studies gave the following results: (i) the application of the electric pulses to the cell suspension, immediately before DOX administration, induced a significant increase of drug retention; (ii) confocal microscopy observations showed a remarkable increase of intranuclear accumulation of DOX induced by electroporation; (iii) cell survival assay revealed a decrease of cell viability in the cultures treated with the combination of electroporation and doxorubicin; (iv) scanning electron microscopy observations revealed consistent morphological changes after the combined exposure to electroporation and doxorubicin; (v) in implanted mice the combined treatment induced an evident slowdown on the tumour growth when compared to treatment with DOX alone; (vi) histopathological analysis evidenced tumour destruction and its replacement by scar tissue in the tumours treated with the combination of doxorubicin and electroporation.

Oxidative Medicine and Cellular Longevity, 2016

Bioorganic Medicinal Chemistry, Feb 1, 2009

Preliminary in vitro cytotoxicity studies on a panel of meso diaryl-substituted tetrapyrrole deri... more Preliminary in vitro cytotoxicity studies on a panel of meso diaryl-substituted tetrapyrrole derivatives newly synthesized in our laboratory have shown that these compounds are photodynamically active on the human colon carcinoma cell line HCT116. In the present study, we investigate some mechanistic aspects of the photodynamic action of the most active compounds in the series, namely the 5-phenyl-15-(3-methoxyphenyl)porphyrin (1), the 5-phenyl-15-(3-hydroxyphenyl)porphyrin (2) and the 5,15-diphenylporphyrin (3). The results of the cytotoxicity studies indicate that the novel photosensitisers (PSs) are more potent in vitro than m-THPC (Foscan), a powerful PS already approved for clinical use in photodynamic therapy (PDT). A series of experiments were performed to elucidate a number of aspects in the mechanism of PS-induced phototoxicity, including, intracellular accumulation and subcellular localization of the PSs, induction of apoptosis, and generation of reactive oxygen species (ROS) and NO*. All the compounds tested exhibit similar singlet oxygen quantum yields; differential intracellular accumulation can contribute to the observed differences in phototoxicity. Flow cytometric studies indicate that all the tested compounds induce apoptosis; however, their cytotoxic effect does not seem to rely solely on this process. Generation of significant amounts of reactive oxygen species (ROS) and NO* were also observed; however, the contribution of this latter effect to the overall phototoxicity is unclear. Taken together, our observations suggest that the diaryl derivatives included in the present study could represent promising leads for the development of novel photosensitizing agents.

The Journal of Microbiology, Dec 1, 2009

The pathogenesis of Legionella pneumophila mainly resides in its ability to inhibit the phagosome... more The pathogenesis of Legionella pneumophila mainly resides in its ability to inhibit the phagosome-lysosome fusion, which normally prevents the killing of the host cells. In order to characterize the molecular alterations that occurred in a spontaneous avirulent mutant of Legionella pneumophila serogroup 6, named Vir-, we investigated the ability of the mutant to adhere to and multiply in the WI26VA4 alveolar epithelial cell line and in human macrophages, when compared to its parental strain, Vir+. We also determined the colocalization of bacteria with LAMP-1 to gain an insight into the phagosome-lysosome fusion process. Additionally, we determined the flagellin expression and dotA nucleotide sequencing. We observed a lack of expression of flagellin and an in-frame mutation in the dotA. gene. The data obtained strongly suggest the loss of virulence of the mutant could probably be due to the absence of flagellin and the dysfunctional type IV secretion System, resulting from the DotA protein being severely compromised.

Oncology Reports, Mar 1, 1994

The action of Lonidamine (LND), a dichlorinated derivative of indazole-3-carboxylic acid, on the ... more The action of Lonidamine (LND), a dichlorinated derivative of indazole-3-carboxylic acid, on the membrane and cytoskeleton of Ehrlich tumor cells was investigated. A remarkable alteration in the molecular organization of the plasma membrane was observed. In particular, changes of plasma membrane and mitochondrial membrane protein distribution were induced by the drug. These membrane alterations were positively related to a rearrangement of microfilaments. In particular, characteristic ring-like structures of actin filaments were observed after 8 h of LND treatment. Intracellular calcium imbalance appeared-to be necessary to produce such peculiar structures. In fact, the administration of a calcium ionophore prevented the actin modifications induced by LND treatment while the simultaneous exposure to the antineoplastic drug verapamil, also considered a calcium channel blocker, was ineffective. The results reported herein suggest that the cytoskeleton as well as cell membranes might be involved in the cytotoxic action of LND and that they could share a common mechanism related to the calcium homeostasis. Moreover, Ehrlich tumor cells display a specific, peculiar rearrangement of F-actin filaments which can be considered as a marker effect of LND.

The Histochemical journal, 2000

P-glycoprotein is a plasma membrane efflux pump which is responsible for multidrug resistance of ... more P-glycoprotein is a plasma membrane efflux pump which is responsible for multidrug resistance of many cancer cell lines. A number of studies have demonstrated the presence of P-glycoprotein molecules, besides on the plasma membrane, also in intracellular sites, such as the Golgi apparatus and the nucleus. In this study, the presence and function of P-glycoprotein in the nuclear membranes of human breast cancer cells (MCF-7 WT) and their multidrug resistant variants (MCF-7 DX) were investigated. Electron and confocal microscopy immunolabelling experiments demonstrated the presence of P-glycoprotein molecules in the nuclear membranes of MCF-7 DX cells. Moreover, the labelling pattern was strongly dependent on pH values of the incubation buffer. At physiological pH (7.2), a strong labelling was detected in the cytoplasm and the nuclear matrix in both sensitive and resistant MCF-7 cells. By raising the pH to 8.0, the P-glycoprotein molecules were easily detected in the cytoplasm (transp...

Toxicology and applied pharmacology, 2010

Engineered nanoparticles offer great promise in many industrial and biomedical applications, howe... more Engineered nanoparticles offer great promise in many industrial and biomedical applications, however little information is available about gastrointestinal toxicity. The purpose of this study was to assess the cytotoxicity, oxidative stress, apoptosis and proinflammatory mediator release induced by ZnO nanoparticles on human colon carcinoma LoVo cells. The biological activity of these particles was related to their physico-chemical characteristics. The physico-chemical characteristics were evaluated by analytical electron microscopy. The cytotoxicity was determined by growth curves and water-soluble tetrazolium assay. The reactive oxygen species production, cellular glutathione content, changes of mitochondrial membrane potential and apoptosis cell death were quantified by flow cytometry. The inflammatory cytokines were evaluated by enzyme-linked immunoadsorbent assay. Treatment with ZnO (5μg/cm(2) corresponding to 11.5μg/ml) for 24h induced on LoVo cells a significant decrease of c...

International journal of oncology, 2005

Multidrug resistance (MDR) in tumor cells is generally associated with increased efflux of the cy... more Multidrug resistance (MDR) in tumor cells is generally associated with increased efflux of the cytotoxic compounds, due to the activation of mechanisms of intracellular transport and to the overexpression of surface proteins, such as P-glycoprotein (Pgp), which act as ATP-dependent molecular pumps. In a previous study, voacamine, a bisindolic alkaloid from Peschiera fuchsiaefolia, was examined for its possible capability of enhancing the cytotoxic effect of doxorubicin (DOX) on resistant human osteosarcoma cells. The effects of voacamine on the cell survival and on accumulation of DOX were investigated on both the parental cell line, U-2 OS-WT, and its resistant counterpart, U-2 OS-R. A differential effect between sensitive and resistant cells on the intracellular DOX concentration and distribution was revealed. In particular, voacamine induced a significant increase of drug retention and intranuclear location in resistant cells. Moreover, the cell survival analysis and the electron...