MGMT genomic rearrangements contribute to chemotherapy resistance in gliomas.

Temozolomide (TMZ) is an oral alkylating agent used for the treatment of glioblastoma and is now becoming a chemotherapeutic option in patients diagnosed with high-risk low-grade gliomas. The O-6-methylguanine-DNA methyltransferase (MGMT) is responsible for the direct repair of the main TMZ-induced toxic DNA adduct, the O6-Methylguanine lesion. MGMT promoter hypermethylation is currently the only known biomarker for TMZ response in glioblastoma patients. Here we show that a subset of recurrent gliomas carries MGMT genomic rearrangements that lead to MGMT overexpression, independently from changes in its promoter methylation. By leveraging the CRISPR/Cas9 technology we generated some of these MGMT rearrangements in glioma cells and demonstrated that the MGMT genomic rearrangements contribute to TMZ resistance both in vitro and in vivo. Lastly, we showed that such fusions can be detected in tumor-derived exosomes and could potentially represent an early detection marker of tumor recurrence in a subset of patients treated with TMZ

Meta-Analysis of the Effects of Foods and Derived Products Containing Ellagitannins and Anthocyanins on Cardiometabolic Biomarkers: Analysis of Factors Influencing Variability of the Individual Responses

peer-reviewedUnderstanding interindividual variability in response to dietary polyphenols remains essential to elucidate their effects on cardiometabolic disease development. A meta-analysis of 128 randomized clinical trials was conducted to investigate the effects of berries and red grapes/wine as sources of anthocyanins and of nuts and pomegranate as sources of ellagitannins on a range of cardiometabolic risk biomarkers. The potential influence of various demographic and lifestyle factors on the variability in the response to these products were explored. Both anthocyanin- and ellagitannin-containing products reduced total-cholesterol with nuts and berries yielding more significant effects than pomegranate and grapes. Blood pressure was significantly reduced by the two main sources of anthocyanins, berries and red grapes/wine, whereas waist circumference, LDL-cholesterol, triglycerides, and glucose were most significantly lowered by the ellagitannin-products, particularly nuts. Additionally, we found an indication of a small increase in HDL-cholesterol most significant with nuts and, in flow-mediated dilation by nuts and berries. Most of these effects were detected in obese/overweight people but we found limited or non-evidence in normoweight individuals or of the influence of sex or smoking status. The effects of other factors, i.e., habitual diet, health status or country where the study was conducted, were inconsistent and require further investigation.This article is based upon work from COST Action FA1403—POSITIVe “Interindividual variation in response to consumption of plant food bioactives and determinants involved” supported by COST (European Cooperation in Science and Technology, http://www.cost.eu/). The authors thank the financial support of the COST Action FA1403 “POSITIVe” to conduct a short-term scientific mission to K.C. at CEBAS-CSIC (A.G.-S. and M.T.G.-C.) during which the data analysis was performed

The spatial and temporal scales of local dengue virus transmission in natural settings:a retrospective analysis

Background Dengue is a vector-borne disease caused by the dengue virus (DENV). Despite the crucial role of Aedes mosquitoes in DENV transmission, pure vector indices poorly correlate with human infections. Therefore there is great need for a better understanding of the spatial and temporal scales of DENV transmission between mosquitoes and humans. Here, we have systematically monitored the circulation of DENV in individual Aedes spp. mosquitoes and human patients from Caratinga, a dengue endemic city in the state of Minas Gerais, in Southeast Brazil. From these data, we have developed a novel stochastic point process pattern algorithm to identify the spatial and temporal association between DENV infected mosquitoes and human patients. Methods The algorithm comprises of: (i) parameterization of the variogram for the incidence of each DENV serotype in mosquitoes; (ii) identification of the spatial and temporal ranges and variances of DENV incidence in mosquitoes in the proximity of humans infected with dengue; and (iii) analysis of the association between a set of environmental variables and DENV incidence in mosquitoes in the proximity of humans infected with dengue using a spatio-temporal additive, geostatistical linear model. Results DENV serotypes 1 and 3 were the most common virus serotypes detected in both mosquitoes and humans. Using the data on each virus serotype separately, our spatio-temporal analyses indicated that infected humans were located in areas with the highest DENV incidence in mosquitoes, when incidence is calculated within 2.5–3 km and 50 days (credible interval 30–70 days) before onset of symptoms in humans. These measurements are in agreement with expected distances covered by mosquitoes and humans and the time for virus incubation. Finally, DENV incidence in mosquitoes found in the vicinity of infected humans correlated well with the low wind speed, higher air temperature and northerly winds that were more likely to favor vector survival and dispersal in Caratinga. Conclusions We have proposed a new way of modeling bivariate point pattern on the transmission of arthropod-borne pathogens between vector and host when the location of infection in the latter is known. This strategy avoids some of the strong and unrealistic assumptions made by other point-process models. Regarding virus transmission in Caratinga, our model showed a strong and significant association between high DENV incidence in mosquitoes and the onset of symptoms in humans at specific spatial and temporal windows. Together, our results indicate that vector surveillance must be a priority for dengue control. Nevertheless, localized vector control at distances lower than 2.5 km around premises with infected vectors in densely populated areas are not likely to be effective

Triplet energy management between two signaling units through cooperative rigid scaffolds

[EN] Through-bond triplet exciplex formation in donor-acceptor systems linked through a rigid bile acid scaffold has been demonstrated on the basis of kinetic evidence upon population of the triplet acceptors (naphthalene, or biphenyl) by through-bond triplet-triplet energy transfer from benzophenone.Financial support from the Spanish Government (Grants SEV-2012-0267, CTQ2012-38754-C03-03, CTQ2013-47872-C2-1-P and JCI-2011-09926), EU (PCIG12GA-2012-334257), Generalitat Valenciana (Prometeo Program), and Technical University of Valencia (VLC/Campus, ASIC-UPV for computational facilities and Predoctoral FPI fellowship for P. Miro) is gratefully acknowledged.Miró Richart, P.; Vayá Pérez, I.; Sastre Navarro, GI.; Jiménez Molero, MC.; Marín García, ML.; Miranda Alonso, MÁ. (2016). Triplet energy management between two signaling units through cooperative rigid scaffolds. Chemical Communications. 52(4):713-716. https://doi.org/10.1039/c5cc08102eS71371652

Importance of the IL-6 / STAT3 signalling pathway in prostate cancer stem cells

Prostate cancer is the most diagnosed cancer in men in the Western world. Currently, most treatments are directed towards an androgen receptor-expressing cell, which encompasses the majority of prostate tumours. Unfortunately, the tumour recurs in the majority of patients. This recurrence is thought to arise due to the presence of a rare population of prostate cancer stem cells. These cells are also hypothesized to be responsible for tumour initiation, maintenance, recurrence and metastasis. It is therefore important to develop novel therapies to target these tumour-initiating cells. Interleukin-6 (IL-6) is a pro-inflammatory cytokine, which is involved in the regulation of a multitude of cellular functions, including proliferation, apoptosis, and differentiation. IL-6 and the associated JAK-STAT signalling pathway have been implicated in the development and progression of a variety of tumours, including prostate cancer. In this study we have demonstrated that these stem-like cells, selected from primary prostate cancer cultures have elevated IL-6 levels and express the IL-6 receptor, suggesting that these cells are constitutively active. Targeting IL-6, and downstream activation of STAT3, resulted in a significant decrease in colony forming ability of these stem-like cells. Moreover, treatment with a small molecule inhibitor of STAT3 resulted in a modest inhibition of tumour growth, with a significant increase in the proportion of CD24+ luminal cells. Whilst the impact on established tumours was modest, LLL12 abolished tumour initiation, suggesting that activation of STAT3, through IL-6, is important for the maintenance of the undifferentiated stem-like cells within prostate tumours. Targeting the JAK-STAT signalling pathway in this cell population might result in a more durable response to current standard of care therapies

Dermal Delivery of Constructs Encoding Cre Recombinase to Induce Skin Tumors in PtenLoxP/LoxP;BrafCA/+ Mice

Current genetically-engineered mouse melanoma models are often based on Tyr::CreERT2-controlled MAPK pathway activation by the BRAFV600E mutation and PI3K pathway activation by loss of PTEN. The major drawback of these models is the occurrence of spontaneous tumors caused by leakiness of the Tyr::CreERT2 system, hampering long-term experiments. To address this problem, we investigated several approaches to optimally provide local delivery of Cre recombinase, including injection of lentiviral particles, DNA tattoo administration and particle-mediated gene transfer, to induce melanomas in PtenLoxP/LoxP;BrafCA/+ mice lacking the Tyr::CreERT2 allele. We found that dermal delivery of the Cre recombinase gene under the control of a non-specific CAG promoter induced the formation of melanomas, but also keratoacanthoma and squamous cell carcinomas. Delivery of Cre recombinase DNA under the control of melanocyte-specific promoters in PtenLoxP/LoxP;BrafCA/+ mice resulted in sole melanoma induction. The growth rate and histological features of the induced tumors were similar to 4-hydroxytamoxifen-induced tumors in Tyr::CreERT2;PtenLoxP/LoxP;BrafCA/+ mice, while the onset of spontaneous tumors was prevented completely. These novel induction methods will allow long-term experiments in mouse models of skin malignancies