Regulação da ativação epigenética do gene MMP2 diante da sinalização da fibronectina em linhagens tumorais de mama

Orientadora : Profª Drª Giseli KlassenCo-orientadora : Profª Drª Edneia A. S. R. CavalieriDissertação (mestrado) - Universidade Federal do Paraná, Setor de Ciências Biológicas, Programa de Pós-Graduação em Microbiologia, Parasitologia e Patologia. Defesa: Curitiba, 02/12/2014Inclui referênciasÁrea de concentraçãoResumo: O câncer de mama é o tipo de câncer mais frequente entre as mulheres em todo o mundo. A enzima MMP-2 é uma metaloprotease capaz de degradar o colágeno tipo IV, um dos principais constituintes da matriz extracelular (MEC). Sua função é amplamente descrita por atuar no mecanismo de metástases em diversos tipos de câncer. Estudos recentes demonstraram que a linhagem tumoral de mama MCF7 possui o gene MMP2 regulado por metilação do DNA. Além disso, alguns estudos têm demonstrado que a fibronectina, uma importante proteína constituinte da MEC, é capaz de promover a expressão de MMP-2 em linhagens tumorais de mama. Resultados recentes do nosso grupo mostraram que a linhagem tumoral MCF7 quando tratada com fibronectina por 5 horas sofre 30% de desmetilação da região promotora do gene MMP2. Entretanto, observou-se também que tal processo foi transitório, porque houve a remetilação parcial do promotor quando o estímulo foi retirado. Ainda, a fibronectina induziu o aumento de uma marca de histona no promotor de MMP2 que sinaliza para a ativação da transcrição gênica. Diante disso, o objetivo deste trabalho foi dar continuidade a esse estudo, avaliando a regulação epigenética do gene MMP2 em linhagens tumorais de mama após o cultivo com fibronectina em diferentes tempos. Para isso, células da linhagem MCF7 submetidas ao tratamento com fibronectina por 8, 12 e 24 horas, e da linhagem MDA-MB-436 por 24 horas, tiveram seus níveis de expressão de MMP2, metilação do DNA e modificações de histonas do promotor do gene avaliados. Na linhagem MCF7, o tratamento por 8, 12 e 24 horas foi capaz de promover o aumento da expressão de MMP2 em 7, 25 e 9 vezes, respectivamente, comparado com o controle, assim como a redução da metilação do promotor de 90% (controle) para 70%, 40% e 52%, respectivamente. O tratamento por 24h também promoveu o aumento da marca de ativação gênica H3K4me3. Ainda, após 12h de cultivo com fibronectina, a linhagem MCF7 aumentou sua capacidade migratória. A fim de verificar se o efeito observado não era exclusivo da linhagem MCF7, foi incluída no estudo a linhagem MDA-MB-436 que foi submetida ao tratamento por 24h, e apresentou aumento na expressão gênica de MMP2 (4 vezes) e redução da metilação do promotor (de 90% para 22%). Por fim, as células tratadas foram mantidas em cultivo sem a fibronectina para avaliar a estabilidade das modificações. Essas células, chamadas de recultivo, apresentaram uma redução na expressão gênica e aumento na metilação do promotor quando comparadas com as células logo após os tratamentos, confirmando o efeito transitório da fibronectina nos eventos epigenéticos, que já tinha sido observado após 5 horas de tratamento. Esses dados corroboram e complementam os mecanismos observados pelo nosso grupo de pesquisa e contribuem para a compreensão dos mecanismos epigenéticos que regulam a expressão de um importante gene associado às metástases tumorais. Palavras-chave: Câncer de mama, MMP-2, epigenética, metilação do DNA.Abstract: Breast cancer is the most common cancer worldwide among women. The MMP- 2 enzyme is a metalloprotease capable of degrading type IV collagen, a major constituent of the extracellular matrix (ECM). Its function is widely described by acting in the mechanism of metastasis in various cancers. Recent data has shown that the MCF7 breast tumor cell line has the MMP2 gene regulated by DNA methylation. In addition, some studies have shown that fibronectin, an important constituent of the extracellular matrix, is capable of promoting MMP-2 expression in breast tumor cell lines. Recent results from our group showed that fibronectin was able to induce MMP2 expression by a 30% decrease in its promoter methylation in MCF7 tumor cell line. However, it was also noted that this process was transient, because a partial promoter remethylation was observed when the stimulus was removed. Moreover, a histone marker for an open chromatin conformation was significantly increased. Therefore, the aim of this work was to continue evaluating the epigenetic regulation of the MMP2 gene after cultivation of breast tumor cell lines with fibronectin at different times. To this reason, MCF7 cells subjected to treatment with fibronectin for 8, 12 and 24 hours and MDA-MB-436 cells subjected to treatment for 24 hours, were evaluated by the levels of MMP2 expression, gene promoter DNA methylation and histone modifications. In the MCF7 cell line, treatments for 8, 12 and 24 hours were able to promote 7, 9 and 25-fold increase in MMP2 expression, respectively, compared with the mock. In addition, promoter methylation was reduced from 90% (control) to 70%, 40% and 52%, respectively. Treatment for 24h also promoted an increase of the histone open chromatin conformation marker H3K4me3. Moreover, the migratory capacity of MCF7 cells treated for 12h was increased. In order to confirm the fibronectin effect, the MDA-MB-436 cell line was subjected to 24h fibronectin treatment, which showed an increase in MMP2 gene expression (4-fold) and a reduction of promoter methylation (from 90% to 22%). Finally, the treated cells were kept in culture without fibronectin to evaluate the modifications stability. These cells (recultivation) showed a gene expression reduction and promoter methylation increased when compared to the cells after treatments, confirming the fibronectin transient effect observed after the 5h treatment. These data support and complement the mechanisms observed by our research group and contribute to understand the epigenetic mechanisms that regulate the expression of an important gene associated with tumor metastasis. Keywords: Breast cancer, MMP-2, epigenetics, DNA methylation

Factors associated with oxidative stress in virologically suppressed people living with HIV on long-term antiretroviral therapy

Background: Oxidative stress (OS) is the imbalance between oxidant and antioxidant molecules, in favour of oxidants, that has been associated with an increased risk of morbidity and mortality in ART-treated people living with HIV (PLWH). We aimed to assess factors associated with OS in virologically suppressed PLWH on long-term modern ART. Method: In this cross-sectional study we evaluated OS by measuring both the levels of derivatives-reactive oxygen metabolites (d-ROMs) and the biological antioxidant potential (BAP). We also calculated the BAP/d-ROMs ratio, (OS index, OSi); a cut-off value < 7.3 indicated OS. Factors associated with OS markers were explored by linear regression model. Results: We enrolled 299 experienced PLWH with virological suppression (HIV-RNA < 50cps/mL). The mean of the d-ROMs levels was 409 UCARR (95%CI 394–422), whereas the mean of the BAP levels was 1.809 μmol/L (95%CI 1706–1851). The OSi mean value was 4.84, and 91.6% of the participants were below the cut-off value. By regression analysis, higher production of oxidants was associated with female sex (p < 0.001), current exposition to PIs (p = 0.030) and HCV co-infection (p = 0.006). Higher antioxidant capacity was correlated with higher HDL levels (p = 0.001). A lower OSi was associated with female sex (p = 0.003) and the current use of triple vs. dual regimen (p = 0.036). The OSi correlated negatively with cholesterol levels (p = 0.002) and positively with HDL (p < 0.001). Conclusions: Virologically suppressed PLWH on long-term ART showed a marked OS. Female sex, the exposure to PIs, and HCV co-infection were associated with higher oxidants, while higher HDL levels were linked to better antioxidant capacity. Interestingly, dual therapy, especially INSTI-based regimens, was associated with lower oxidative stress compared to triple therapy

Urinary tract infections caused by Gram-negative bacteria in elderly hospitalized patients: epidemiology, clinical features and outcomes in the era of antimicrobial resistance

Objectives: Urinary tract infections (UTI) are among the most common infections in elderly hospitalized patients, often caused by multi-drug resistant (MDR) organisms and characterised by poor clinical outcomes. This study aimed to evaluate the clinical characteristics, microbiology, treatment patterns, and predictors of mortality in elderly hospitalized patients with UTI, with a focus on infections caused by MDR Gram-negative bacteria (MDR-GNB). Methods: A retrospective analysis was conducted on 171 patients. Data on demographics, comorbidities, infection characteristics, antimicrobial resistance, treatments, and outcomes were collected. Risk factors for MDR-GNB UTI and predictors of 14-day mortality were identified through univariable and multivariable analyses. Results: Of 171 patients (median age: 82 years), 106 (62.0%) had a catheter-associated UTI (CAUTI), and 105 (61.4%) had a healthcare-associated UTI. MDR-GNB were isolated in 68.4% of cases. Common pathogens included Escherichia coli (74/171, 43.3%), Klebsiella spp. (39/171, 22.8%) and Pseudomonas aeruginosa (33/171, 19.3%). Among Enterobacterales 35.1% were Extended-spectrum β-lactamases (ESBL)-producers, 3.7% carried Klebsiella pneumoniae carbapenemase (KPC), and 3.0% metallo-β -lactamases (MBL). Overall, the 14-day mortality rate was 12.9%. Predictors of 14-day mortality included septic shock, infections caused by Providencia stuartii, infections caused by New Delhi metallo-β-lactamase (NDM)-producing Klebsiella pneumoniae, and inappropriate empirical antibiotic therapy. Conclusions: UTI significantly affect hospital length of stay and mortality in elderly patients. In the current context, resistance mechanisms including KPC and MBL production, must be considered when managing these infections. Prompt recognition of risk factors for infections caused by MDR organisms and optimized antimicrobial strategies are essential to improve outcomes in this vulnerable population

Comparative determination of HIV-1 co-receptor tropism by Enhanced Sensitivity Trofile, gp120 V3-loop RNA and DNA genotyping

BACKGROUND: Trofile is the prospectively validated HIV-1 tropism assay. Its use is limited by high costs, long turn-around time, and inability to test patients with very low or undetectable viremia. We aimed at assessing the efficiency of population genotypic assays based on gp120 V3-loop sequencing for the determination of tropism in plasma viral RNA and in whole-blood viral DNA. Contemporary and follow-up plasma and whole-blood samples from patients undergoing tropism testing via the enhanced sensitivity Trofile (ESTA) were collected. Clinical and clonal geno2pheno[coreceptor] (G2P) models at 10% and at optimised 5.7% false positive rate cutoff were evaluated using viral DNA and RNA samples, compared against each other and ESTA, using Cohen's kappa, phylogenetic analysis, and area under the receiver operating characteristic (AUROC). RESULTS: Both clinical and clonal G2P (with different false positive rates) showed good performances in predicting the ESTA outcome (for V3 RNA-based clinical G2P at 10% false positive rate AUROC = 0.83, sensitivity = 90%, specificity = 75%). The rate of agreement between DNA- and RNA-based clinical G2P was fair (kappa = 0.74, p < 0.0001), and DNA-based clinical G2P accurately predicted the plasma ESTA (AUROC = 0.86). Significant differences in the viral populations were detected when comparing inter/intra patient diversity of viral DNA with RNA sequences. CONCLUSIONS: Plasma HIV RNA or whole-blood HIV DNA V3-loop sequencing interpreted with clinical G2P is cheap and can be a good surrogate for ESTA. Although there may be differences among viral RNA and DNA populations in the same host, DNA-based G2P may be used as an indication of viral tropism in patients with undetectable plasma viremia

Trajectory of Spike-Specific B Cells Elicited by Two Doses of BNT162b2 mRNA Vaccine

: The mRNA vaccines for SARS-CoV-2 have demonstrated efficacy and immunogenicity in the real-world setting. However, most of the research on vaccine immunogenicity has been centered on characterizing the antibody response, with limited exploration into the persistence of spike-specific memory B cells. Here we monitored the durability of the memory B cell response up to 9 months post-vaccination, and characterized the trajectory of spike-specific B cell phenotypes in healthy individuals who received two doses of the BNT162b2 vaccine. To profile the spike-specific B cell response, we applied the tSNE and Cytotree automated approaches. Spike-specific IgA+ and IgG+ plasmablasts and IgA+ activated cells were observed 7 days after the second dose and disappeared 3 months later, while subsets of spike-specific IgG+ resting memory B cells became predominant 9 months after vaccination, and they were capable of differentiating into spike-specific IgG secreting cells when restimulated in vitro. Other subsets of spike-specific B cells, such as IgM+ or unswitched IgM+IgD+ or IgG+ double negative/atypical cells, were also elicited by the BNT162b2 vaccine and persisted up to month 9. The analysis of circulating spike-specific IgG, IgA, and IgM was in line with the plasmablasts observed. The longitudinal analysis of the antigen-specific B cell response elicited by mRNA-based vaccines provides valuable insights into our understanding of the immunogenicity of this novel vaccine platform destined for future widespread use, and it can help in guiding future decisions and vaccination schedules

B cell response after SARS-CoV-2 mRNA vaccination in people living with HIV

Background: Limited longitudinal data are available on immune response to mRNA SARS-CoV-2 vaccination in people living with HIV (PLWHIV); therefore, new evidence on induction and persistence of spike-specific antibodies and B cells is needed. Methods: In this pilot study we investigated the spike-specific humoral and B cell responses up to six months after vaccination with two doses of mRNA vaccines in 84 PLWHIV under antiretroviral therapy compared to 79 healthy controls (HCs). Results: Spike-specific IgG persisted six months in PLWHIV with no significant differences compared to HCs, even though a significantly lower IgG response was observed in patients with CD4+ T cells &lt; 350/mmc. The frequency of subjects with antibodies capable of inhibiting ACE2/RBD binding was comparable between PLWHIV and HCs a month after the second vaccine dose, then a higher drop was observed in PLWHIV. A comparable percentage of spike-specific memory B cells was observed at month six in PLWHIV and HCs. However, PLWHIV showed a higher frequency of spike-specific IgD- CD27- double-negative memory B cells and a significantly lower rate of IgD- CD27+ Ig-switched memory B cells compared to HCs, suggesting a reduced functionality of the antigen-specific memory B population. Conclusions: The mRNA vaccination against SARS-CoV-2 elicits humoral and B cell responses quantitatively similar between PLWHIV and HCs, but there are important differences in terms of antibody functionality and phenotypes of memory B cells, reinforcing the notion that tailored vaccination policies should be considered for these patients

TRAIL receptors are expressed in both malignant and stromal cells in pancreatic ductal adenocarcinoma

: This study assesses the expression of all TNF-related apoptosis-inducing ligand (TRAIL) receptors in pancreatic ductal adenocarcinoma (PDAC) tumor tissue. We aimed to include TRAIL receptor expression as an inclusion parameter in a future clinical study using a TRAIL-based therapy approach for PDAC patients. Considering the emerging influence of PDAC desmoplastic stroma on the efficacy of anti-PDAC therapies, this analysis was extended to tumor stromal cells. Additionally, we performed PDAC stroma characterization. Our retrospective cohort study (N=50) included patients with histologically confirmed PDAC who underwent surgery. The expression of TRAIL receptors (DR4, DR5, DcR1, DcR2, and OPG) in tumor and stromal cells was evaluated by immunohistochemistry (IHC). The amount of tumor stroma was assessed by anti-vimentin IHC and Mallory's trichrome staining. The prognostic impact was determined by the univariate Cox proportional hazards regression model. An extensive expression of functional receptors DR4 and DR5 and a variable expression of decoy receptors were detected in PDAC tumor and stromal cells. Functional receptors were detected also in metastatic tumor and stromal cells. A poor prognosis was associated with low or absent expression of decoy receptors in tumor cells of primary PDAC. After assessing that almost 80% of tumor mass was composed of stroma, we correlated a cellular-dense stroma in primary PDAC with reduced relapse-free survival. We demonstrated that TRAIL functional receptors are widely expressed in PDAC, representing a promising target for TRAIL-based therapies. Further, we demonstrated that a low expression of DcR1 and the absence of OPG in tumor cells, as well as a cellular-dense tumor stroma, could negatively impact the prognosis of PDAC patients

Results from a European multi-cohort study

Publisher Copyright: © 2021 The Author(s) 2021. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved.Background: INSTIs have become a pillar of first-line ART. Real-world data are needed to assess their effectiveness in routine care. Objectives: We analysed ART-naive patients who started INSTI-based regimens in 2012-19 whose data were collected by INTEGRATE, a European collaborative study including seven national cohorts. Methods: Kaplan-Meier analyses assessed time to virological failure (VF), defined as one viral load (VL) ≥1000 copies/mL, two consecutive VLs ≥50 copies/mL, or one VL ≥50 copies/mL followed by treatment change after ≥24 weeks of follow-up, and time to INSTIs discontinuation (INSTI-DC) for any reason. Factors associated with VF and INSTI-DC were explored by logistic regression analysis. Results: Of 2976 regimens started, 1901 (63.9%) contained dolutegravir, 631 (21.2%) elvitegravir and 444 (14.9%) raltegravir. The 1 year estimated probabilities of VF and INSTI-DC were 5.6% (95% CI 4.5-6.7) and 16.2% (95% CI 14.9-17.6), respectively, and were higher for raltegravir versus both elvitegravir and dolutegravir. A baseline VL ≥100 000 copies/mL [adjusted HR (aHR) 2.17, 95% CI 1.55-3.04, P 3 drugs versus 3 drugs (aHR 2.73, 95% CI 1.55-4.79, P < 0.001) and starting ART following availability of dolutegravir (aHR 0.64, 95% CI 0.48-0.83, P = 0.001). Major INSTI mutations indicative of transmitted drug resistance occurred in 2/1114 (0.2%) individuals. Conclusions: This large multi-cohort study indicates high effectiveness of elvitegravir- or dolutegravir-based first-line ART in routine practice across Europe.publishersversionpublishe

Inhibition of ERK1/2 signaling prevents bone marrow fibrosis by reducing osteopontin plasma levels in a myelofibrosis mouse model

Clonal myeloproliferation and development of bone marrow (BM) fibrosis are the major pathogenetic events in myelofibrosis (MF). The identification of novel antifibrotic strategies is of utmost importance since the effectiveness of current therapies in reverting BM fibrosis is debated. We previously demonstrated that osteopontin (OPN) has a profibrotic role in MF by promoting mesenchymal stromal cells proliferation and collagen production. Moreover, increased plasma OPN correlated with higher BM fibrosis grade and inferior overall survival in MF patients. To understand whether OPN is a druggable target in MF, we assessed putative inhibitors of OPN expression in vitro and identified ERK1/2 as a major regulator of OPN production. Increased OPN plasma levels were associated with BM fibrosis development in the Romiplostim-induced MF mouse model. Moreover, ERK1/2 inhibition led to a remarkable reduction of OPN production and BM fibrosis in Romiplostim-treated mice. Strikingly, the antifibrotic effect of ERK1/2 inhibition can be mainly ascribed to the reduced OPN production since it could be recapitulated through the administration of anti-OPN neutralizing antibody. Our results demonstrate that OPN is a novel druggable target in MF and pave the way to antifibrotic therapies based on the inhibition of ERK1/2-driven OPN production or the neutralization of OPN activity

Evolution of Self-reported Neuropsychiatric Symptoms After Switching from Dolutegravir/Abacavir/Lamivudine to Bictegravir/Emtricitabine/Tenofovir Alafenamide: Results from the Randomized DOBINeuro Trial

Introduction: Central nervous system adverse events (AE) have been a cause of discontinuation of dolutegravir-containing therapy, especially in combination with abacavir. The main aim of the study was to evaluate whether the switch to bictegravir/emtricitabine/tenofovir alafenamide (BIC/FTC/TAF) was associated with a reduction in severity and incidence of neuropsychiatric symptoms compared to continued dolutegravir/abacavir/lamivudine (DTG/ABC/3TC). Methods: DOBINeuro is a randomized trial enrolling people living with HIV (PLWH) treated with DTG/ABC/3TC for &gt; 6&nbsp;months and with HIV-RNA &lt; 50 cps/ml for &gt; 12&nbsp;months. At baseline, PLWH are randomized to continue DTG/ABC/3TC or switch to BIC/FTC/TAF. The original sample size was 50 PLWH per arm, but the enrollment was prematurely stopped due to a delayed recruitment process. Neuropsychiatric symptoms were evaluated by the self-report Symptom Checklist (SCL)-90-R and the Mini-International Neuropsychiatric Interview Plus. Results: A total of 41 PLWH were enrolled and underwent randomization: 20 were randomized to continue DTG/ABC/3TC and 21 to switch to BIC/FTC/TAF. At baseline, clinical and laboratory characteristics were homogeneous in the two arms. Switching from DTG/ABC/3TC to BIC/FTC/TAF in virologically suppressed PLWH was associated with an improvement in sleep disorders but not in any other neuropsychiatric symptom. Conclusions: Although limited by a low sample size, this study suggests neuropsychiatric tolerability may improve when switching virologically suppressed PLWH from DTG to BIC-based strategies