Navegando por Palavras-chave "HeLa cells"

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    Adesão de Escherichia coli a células hela: correlação com sorogrupos, sorotipos e biosorotipos, aspectos genéticos da adesão
    (Universidade Federal de São Paulo (UNIFESP), 1985) Scaletsky, Isabel Cristina Affonso [UNIFESP]; Trabulsi, Luiz Rachid [UNIFESP]
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    Candida albicans: The Ability to Invade Epithelial Cells and Survive under Oxidative Stress Is Unlinked to Hyphal Length
    (Frontiers Media Sa, 2017) Maza, Paloma K. [UNIFESP]; Bonfim-Melo, Alexis [UNIFESP]; Padovan, Ana C. B. [UNIFESP]; Mortara, Renato A. [UNIFESP]; Orikaza, Cristina M. [UNIFESP]; Damas Ramos, Lilian M.; Moura, Tauany R.; Soriani, Frederico M.; Almeida, Ricardo S.; Suzuki, Erika [UNIFESP]; Bahia, Diana [UNIFESP]
    In its hyphal form, Candida albicans invades epithelial and endothelial cells by two distinct mechanisms: active penetration and induced endocytosis. The latter is dependent on a reorganization of the host cytoskeleton (actin/cortactin recruitment), whilst active penetration does not rely on the host's cellular machinery. The first obstacle for the fungus to reach deep tissues is the epithelial barrier and this interaction is crucial for commensal growth, fungal pathogenicity and host defense. This study aimed to characterize in vitro epithelial HeLa cell invasion by four different isolates of C. albicans with distinct clinical backgrounds, including a C. albicans SC5314 reference strain. All isolates invaded HeLa cells, recruited actin and cortactin, and induced the phosphorylation of both Src-family kinases (SFK) and cortactin. Curiously, L3881 isolated from blood culture of a patient exhibited the highest resistance to oxidative stress, although this isolate showed reduced hyphal length and displayed the lowest cell damage and invasion rates. Collectively, these data suggest that the ability of C. albicans to invade HeLa cells, and to reach and adapt to the host's blood, including resistance to oxidative stress, may be independent of hyphal length.
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    Circadian variation and in vitro cytotoxic activity evaluation of volatile compounds from leaves of Piper regnellii (Miq) C. DC. var. regnellii (C. DC.) Yunck (Piperaceae)
    (Taylor & Francis Ltd, 2018) Anderson, Roseli R. [UNIFESP]; Girola, Natalia [UNIFESP]; Figueiredo, Carlos R. [UNIFESP]; Londero, Vinicius S. [UNIFESP]; Lago, Joao Henrique G.
    Aiming detection of circadian variation in the chemical composition of volatiles from Piper regnellii, the leaves were collected during four different periods (8, 12, 16 and 20 h) in the same day. After extraction by hydrodistillation and GC/MS analysis, no significant variation was observed for the main compounds: germacrene D (45.6 +/- 1.5-51.4 +/- 3.1%), alpha-chamigrene (8.9 +/- 1.3-11.3 +/- 2.7%) and beta-caryophyllene (8.2 +/- 0.9-9.5 +/- 0.3%). Evaluation of in vitro cytotoxicity against several cancer and non-tumourigenic cells indicated promising activity, especially to HeLa (human cervical carcinoma) with IC50 ranging from 11 +/- 3 to 17 +/- 3 mu g/mL. The obtained volatile oils were pooled and subjected to fractionation to afford pure beta-caryophyllene, alpha-chamigrene and germacrene D, being this last compound the more active against HeLa cells with IC50 of 7 +/- 1 mu g/mL (34 +/- 5 mu M). Therefore, the predominance of germacrene D in all analysed oils could justify, at least in part, the activity observed for the volatile compounds from P. regnellii leaves. [GRAPHICS] .
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    Pouterin, a novel potential cytotoxic lectin-like protein with apoptosis-inducing activity in tumorigenic mammalian cells
    (Elsevier B.V., 2008-06-15) Boleti, Ana Paula de A.; Ventura, Claudio A.; Justo, Giselle Z. [UNIFESP]; Silva, Rodrigo A.; Sousa, Ana Carolina T. de; Ferreira, Carmen V.; Yano, Tomomasa; Macedo, Maria Ligia R.; Univ Fed Mat Grosso Sul; Universidade Estadual de Campinas (UNICAMP); Universidade Federal de São Paulo (UNIFESP)
    In this study, the cytotoxicity of pouterin in tumorigenic and non-tumorigenic mammalian cell lines was investigated. We found that HeLa, Hep-2 and HT-29 tumor cells were highly sensitive to pouterin cytotoxicity in a dose-dependent manner, whereas non-tumorigenic Vero cells and human lymphocytes were relatively resistant to the protein. Among the tumor cell lines, HeLa cells showed the highest susceptibility to pouterin cytotoxicity, exhibiting a time-dependent increase in LDH leakage and an IC50 value of 5 mu g/mL. Morphological alterations such as rounding, cell shrinkage and chromatin condensation, consistent with apoptotic cell death were observed. Apoptosis induction was demonstrated by DNA fragmentation as detected by terminal dUTP nick-end labeling (TUNEL). Furthermore, HeLa cells incubated with pouterin showed disruption of the actin cytoskeleton. Western blot analysis revealed that pouterin caused increased expression of p21, thus indicating cell cycle arrest. Subsequent studies provided evidence that apoptosis may be partially explained in the activation of the tumor necrosis factor receptor 1 (TNFR1) signaling. Interestingly, a time-dependent decrease of the expression of p65 nuclear factor kappa B (NF kappa B) subunit, concomitant with a downregulation of the inhibitor of apoptosis protein 1 (IAP1) was observed, suggesting that TNFR-mediated apoptosis is the predominant pathway induced by pouterin in HeLa cells. (c) 2008 Elsevier B.V. All rights reserved.