Effects of tumor derived exosomes on T cells markers expression / Efeitos de exossomos derivados de tumor na expressão de marcadores de células T

Exosomes are 30-120nm bio particles transferred from donor to recipient cells leading to modification in their regulatory mechanisms depending upon the coded message in the form of loaded biomolecule. Cancer cells derived exosomes the true representatives of the parent cells have been found to modify the tumor surrounding/distinct regions and participate in metastasis, angiogenesis and immune suppression. Tis study was aimed to study the effects of tumor mice derived exosomes on the normal mice spleen isolated T cells by using co-culture experiments and flow cytometer analysis. We mainly focused on some of the T cells population and cytokines including IFN-γ, FOXP3+ regulatory T (Treg) cells and KI67 (proliferation marker). Overall results indicated random changes in different set of experiments, where the cancer derived exosomes reduced the IFN-γ expression in both CD4 and CD8 T cells, similarly the Treg cells were also found decreased in the presence of cancer exosomes. No significant changes were observed on the Ki67 marker expression. Such studies are helpful in understanding the role of cancer exosomes in immune cells suppression in tumor microenvironment. Cancer exosomes will need to be validated in vivo and in vitro on a molecular scale in detail for clinical applications.

Os exossomos são biopartículas de 30-120 nm transferidas de células doadoras para células receptoras, levando à modificação em seus mecanismos reguladores, dependendo da mensagem codificada na forma de biomolécula carregada. Verificou-se que exossomos derivados de células cancerosas ­ os verdadeiros representantes das células-mãe ­ modificam as regiões circundantes / distintas do tumor e participam da metástase, angiogênese e imunossupressão. Este estudo teve como objetivo estudar os efeitos de exossomos derivados de camundongos com tumor nas células T isoladas de baço de camundongos normais, usando experimentos de cocultura e análise de citômetro de fluxo. Concentrou-se, principalmente, em algumas populações de células T e citocinas, incluindo IFN-γ, células T reguladoras FOXP3 + (Treg) e KI67 (marcador de proliferação). Os resultados gerais indicaram mudanças aleatórias em diferentes conjuntos de experimentos, em que os exossomos derivados de câncer reduziram a expressão de IFN-γ em células T CD4 e CD8, da mesma forma que as células Treg também foram encontradas diminuídas na presença de exossomos de câncer. Nenhuma mudança significativa foi observada na expressão do marcador Ki67. Esses dados são úteis para a compreensão do papel dos exossomos do câncer na supressão de células do sistema imunológico no microambiente tumoral. Exossomos de câncer precisarão ser validados in vivo e in vitro em escala molecular com detalhes para aplicações clínicas.

Effects of tumor derived exosomes on T cells markers expression

Abstract Exosomes are 30-120nm bio particles transferred from donor to recipient cells leading to modification in their regulatory mechanisms depending upon the coded message in the form of loaded biomolecule. Cancer cells derived exosomes the true representatives of the parent cells have been found to modify the tumor surrounding/distinct regions and participate in metastasis, angiogenesis and immune suppression. Tis study was aimed to study the effects of tumor mice derived exosomes on the normal mice spleen isolated T cells by using co-culture experiments and flow cytometer analysis. We mainly focused on some of the T cells population and cytokines including IFN-, FOXP3+ regulatory T (Treg) cells and KI67 (proliferation marker). Overall results indicated random changes in different set of experiments, where the cancer derived exosomes reduced the IFN- expression in both CD4 and CD8 T cells, similarly the Treg cells were also found decreased in the presence of cancer exosomes. No significant changes were observed on the Ki67 marker expression. Such studies are helpful in understanding the role of cancer exosomes in immune cells suppression in tumor microenvironment. Cancer exosomes will need to be validated in vivo and in vitro on a molecular scale in detail for clinical applications.

Resumo Os exossomos são biopartículas de 30-120 nm transferidas de células doadoras para células receptoras, levando à modificação em seus mecanismos reguladores, dependendo da mensagem codificada na forma de biomolécula carregada. Verificou-se que exossomos derivados de células cancerosas os verdadeiros representantes das células-mãe modificam as regiões circundantes / distintas do tumor e participam da metástase, angiogênese e imunossupressão. Este estudo teve como objetivo estudar os efeitos de exossomos derivados de camundongos com tumor nas células T isoladas de baço de camundongos normais, usando experimentos de cocultura e análise de citômetro de fluxo. Concentrou-se, principalmente, em algumas populações de células T e citocinas, incluindo IFN-, células T reguladoras FOXP3 + (Treg) e KI67 (marcador de proliferação). Os resultados gerais indicaram mudanças aleatórias em diferentes conjuntos de experimentos, em que os exossomos derivados de câncer reduziram a expressão de IFN- em células T CD4 e CD8, da mesma forma que as células Treg também foram encontradas diminuídas na presença de exossomos de câncer. Nenhuma mudança significativa foi observada na expressão do marcador Ki67. Esses dados são úteis para a compreensão do papel dos exossomos do câncer na supressão de células do sistema imunológico no microambiente tumoral. Exossomos de câncer precisarão ser validados in vivo e in vitro em escala molecular com detalhes para aplicações clínicas.

Effects of tumor derived exosomes on T cells markers expression.

Exosomes are 30-120nm bio particles transferred from donor to recipient cells leading to modification in their regulatory mechanisms depending upon the coded message in the form of loaded biomolecule. Cancer cells derived exosomes the true representatives of the parent cells have been found to modify the tumor surrounding/distinct regions and participate in metastasis, angiogenesis and immune suppression. Tis study was aimed to study the effects of tumor mice derived exosomes on the normal mice spleen isolated T cells by using co-culture experiments and flow cytometer analysis. We mainly focused on some of the T cells population and cytokines including IFN-γ, FOXP3+ regulatory T (Treg) cells and KI67 (proliferation marker). Overall results indicated random changes in different set of experiments, where the cancer derived exosomes reduced the IFN-γ expression in both CD4 and CD8 T cells, similarly the Treg cells were also found decreased in the presence of cancer exosomes. No significant changes were observed on the Ki67 marker expression. Such studies are helpful in understanding the role of cancer exosomes in immune cells suppression in tumor microenvironment. Cancer exosomes will need to be validated in vivo and in vitro on a molecular scale in detail for clinical applications.

Ag-enriched TiO2 nanocoating apposite for self-sanitizing/ self-sterilizing/ self-disinfecting of glass surfaces.

The excellent strategy to mitigate the spread of the COVID-19 pandemic is to inhibit the transmission of the SARS-CoV-2. Since fomites are one of the vital routes of coronaviral transmission, disinfecting of fomites play a pivotal role in curbing its survival on the contaminated surfaces. Available commercial disinfectants cannot keep the contaminated surfaces sanitized all the time. Self-disinfecting ability of Ag-enriched TiO2 nanocoating due to its superb photocatalytic efficiency can effectively reduce infections caused by spread of pathogens at public places. Anatase Ag-TiO2 nanocoatings synthesized by sol-gel process at 0.5, 1.5, and 2.5% enriching concentrations were casted on glass substrates by spin-coating technique and subsequently annealed at 650 °C. The morphological shape, crystallographic structure, light absorbance, photo-luminosity, vibrational modes, and functional groups of Ag-TiO2 nanocoating on glass surface were studied by FE-SEM, GIXRD, UV-Visible, Photoluminescence, Raman, and FTIR spectroscopy. The developed anatase Ag-TiO2 nanocoatings manifested to improve photocatalytic disinfecting performance due to the achieved small crystallite size of 10.5-19.2 nm, diminished band gap energy of 2.56-2.60 eV, elevated surface area of 0.802-1.470 ×105 cm2/g, and enhanced light absorbance. Among the enriched specimens, 0.5% Ag-TiO2 nanocoatings predicted an overall exalted functionality compared to pristine one.

Pyrazinamide-resistant mycobacterium tuberculosis isolates from Khyber Pakhtunkhwa and rpsA mutations.

Pyrazinamide (PZA) is a key first-line antibiotic used for the short-course treatment of drug-sensitive and multidrug-resistant (MDR) isolates of tuberculosis. PZA exhibits potent action against semi-dormant bacilli in acidic environments. However, mutations that occur in target genes may cause technical difficulties in the diagnosis of PZA resistance during drug susceptibility testing. The objective of the current study is to identify mutations in pncAWT rpsA and rpsAWT panD genes among PZA-resistant isolates of Mycobacterium tuberculosis (MTB) circulating in the Pashtun dominant region, Khyber Pakhtunkhwa, Pakistan. We selected 18 PZA-resistant pncAWT strains from the Provincial Tuberculosis Reference Laboratory (PTRL) Khyber Pakhtunkhwa to investigate mutations in the coding region of rpsA and panD genes. The experiments were repeated for drug susceptibility testing using MGIT 960 automated system. In addition, eighteen PZA-resistant rpsA genes along with 5 susceptible strains and one H37Rv strain were sequenced. All 18 isolates were PZA-resistant. The majority of these isolates exhibited multidrug resistance (MDR) (13/18). We identified 14 non-synonymous and one synonymous mutation in the coding region of rpsA in 11 strains. All mutations were scattered throughout the gene and not reported previously. Further, we did not identify any mutation in 7 rpsAWT panD genes. Mutations in rpsA but not in panD occur in PZA-resistant pncAWT MTB isolates circulating in Khyber Pakhtunkhwa, Pakistan.

Lack of association between GSTT1 polymorphism and endogenous or benzo[a]pyrene-induced sister chromatid exchanges as analyzed in metaphase or G2-phase lymphocytes.

The objectives of the present work are (1) to verify whether genetic polymorphism in the detoxification gene GSTT1 influences the endogenous sensitivity in terms of sister chromatid exchanges (SCEs)/cell in healthy donors and (2) to test whether in vitro exposure to B[a]P in terms of SCEs/cell can be associated with polymorphism of GSTT1 gene. The presence or absence of the homozygous deletion in GSTT1 gene was determined in peripheral blood cells using multiplex-PCR. For SCEs quantitation, the cytogenetic method used thus far is based on the analysis in metaphase chromosomes. Consequently, G2-arrested cells are not included in the analysis. To overcome this shortcoming of the conventional method, we applied here SCE analysis in G2-phase prematurely condensed chromosomes (G2-PCCs) induced by calyculin-A, using a modified fluorescence-plus-Giemsa staining protocol. Compared to metaphase, a statistically significant increase in the yield of SCEs was notified in the G2-phase analysis after 48 h exposure of peripheral blood lymphocytes to 0.01-1 mM B[a]P, in both GSTT1-positive and -null donors. Therefore, the analysis of SCEs in the G2-phase using calyculin-A induced PCC methodology was shown to be more sensitive compared to the analysis at the metaphase level. Nevertheless, the results obtained do not show an association between the GSTT1 polymorphism with increased endogenous and/or B[a]P-induced SCE-frequencies in peripheral blood lymphocyte chromosomes in vitro. These results highlight not only the effect of B[a]P on cell cycle kinetics but also they demonstrate that conventional cytogenetic analysis at metaphase underestimates the cytogenetic effects of chemicals that delay cell cycle progression in G2-phase.

SCE analysis in G2 lymphocyte prematurely condensed chromosomes after exposure to atrazine: the non-dose-dependent increase in homologous recombinational events does not support its genotoxic mode of action.

Several studies have been carried out to evaluate the mutagenic and carcinogenic potential of atrazine, the most prevalent of triazine herbicides classified as a "possible human carcinogen". The majority of these studies have been negative but positive responses have been also reported including mammary tumors in female Sprague-Dawley rats. Sister chromatid exchanges (SCEs) caused by the presence of DNA lesions at the moment of DNA replication have been extensively used for genotoxicity testing, but for non-cytotoxic exposures to atrazine controversial results have been reported. Even though exposures to higher concentrations of atrazine could provide clear evidence for its genotoxicity, conventional SCE analysis at metaphase cells cannot be used because affected cells are delayed in G2-phase and do not proceed to mitosis. As a result, the genotoxic potential of atrazine may have been underestimated. Since clear evidence has been recently reported relating SCEs to homologous recombinational events, we are testing here the hypothesis that high concentrations of atrazine will cause a dose-dependent increase in homologous recombinational events as quantified by the frequency of SCEs analyzed in G2-phase. Towards this goal, a new cytogenetic approach is applied for the analysis of SCEs directly in G2-phase prematurely condensed chromosomes (PCCs). The methodology enables the visualization of SCEs in G2-blocked cells and is based on drug-induced PCCs in cultured lymphocytes. The results obtained for high concentrations of atrazine do not demonstrate a dose-dependent increase in homologous recombinational events. They do not support, therefore, a genotoxic mode of action. However, they suggest that an important part in the variation of SCE frequency reported by different laboratories when conventional SCE analysis is applied after exposure to a certain concentration of atrazine, is due to differences in cell cycle kinetics of cultured lymphocytes, rather than to a true biological variation in the cytogenetic end point used.

Radioprotective effect of amifostine on cells from cancer prone patients and healthy individuals studied by the G2 and PCC assays.

PURPOSE: To investigate whether amifostine is effective at reducing the yield of chromatid breaks when present during G(2)-phase irradiation of human normal cells and cells from cancer prone patients, as well as to study the mechanisms underlying the radioprotective effect of amifostine. MATERIALS AND METHODS: G(2) chromosomal radiosensitivity in the presence or absence of amifostine was studied in healthy donors, cancer patients, ataxia-telangietasia (A-T) patients and five human lymphoblastoid cell lines with genes predisposing to cancer. The yield of chromatid breaks following gamma-irradiation in G(2) phase was obtained at the subsequent metaphase using the G(2) assay. For scoring chromatid damage directly in G(2) or G(0) phase, premature chromosome condensation was used. RESULTS: When amifostine was present during irradiation, the mean yield of radiation-induced chromatid breaks as visualized by the G(2) assay was significantly reduced in healthy donors (t-test, p=0.001), in cells from cancer patients (p=0.001) and in cell lines from patients with genes predisposing to cancer (p=0.01) except ATM(-/-) (0.1

A new cytogenetic approach for the evaluation of mutagenic potential of chemicals that induce cell cycle arrest in the G2 phase.

The aim of the present study was to develop and standardize a cytogenetic approach for evaluation of the mutagenic potential of chemicals that induce cell cycle arrest in the G2 phase. Even though cytogenetic end-points such as sister chromatid exchange (SCE) have been extensively used to indirectly assess the DNA-damaging potential of various chemicals, they are based on metaphase chromosome analysis. Cells delayed in G2 phase after chemical exposure are not included in conventional SCE analysis. The yield of SCEs obtained, therefore, can be biased, since predominantly undamaged cells proceed to metaphase without delay. To overcome this shortcoming of conventional SCE analysis, the use of a new cytogenetic approach for genotoxic studies is presented that enables the analysis of SCEs directly in G2 phase using drug-induced premature chromosome condensation in cultured peripheral blood lymphocytes. By means of this method, firstly, the possibility that SCE analysis in metaphase chromosomes underestimates the mutagenic potential of various chemicals was tested. Secondly, whether the genotoxic potential of suspected carcinogens could be evaluated using SCE analysis in G2 phase, even at exposures that arrest cells in G2 phase, was examined. Thirdly, whether an important part of the background variation in SCE frequency among individuals is due to the delay of affected cells in G2 phase, rather than to a true biological variation in the cytogenetic end-point used, was tested. The results showed that a higher SCE frequency was scored in G2 phase than in metaphase. Subsequently, the mutagenic potential of chemicals that temporarily arrest cells in G2 phase could now be evaluated more accurately. In addition, it may be of interest to further examine the involvement of cell cycle kinetics in the baseline SCE variation among individuals since a lesser SCE variability was observed when the analysis was carried out in G2 phase rather than at metaphase.