O Messianismo na Legitimação Simbólica de D. João I (1383-85/1433)

A ascensão da Dinastia de Avis em Portugal colocou no poder o bastardo D. João I, vencedor da assim chamada Revolução de Avis. Após a sua morte, para consolidar a transmissão do poder a seus descendentes, era necessário elaborar uma cuidadosa justificativa de seu governo, tornando-o, no plano simbólico, legítimo. Tal tarefa coube ao cronista régio Fernão Lopes que, na Crónica de D. João I, utilizou-se da religiosidade medieval e da expectativa de final dos tempos para justificar o novo rei. Lopes apresenta no documento uma série de sinais e milagres, acolhendo-os como confirmação da escolha divina do novo monarca, e apresenta o combate entre D. João de Portugal e D. João de Castela como a luta entre o Messias de Lisboa e o Anticristo . &nbsp

Targeting ATR in vivo using the novel inhibitor VE-822 results in selective sensitization of pancreatic tumors to radiation.

Combined radiochemotherapy is the currently used therapy for locally advanced pancreatic ductal adenocarcinoma (PDAC), but normal tissue toxicity limits its application. Here we test the hypothesis that inhibition of ATR (ATM-Rad3-related) could increase the sensitivity of the cancer cells to radiation or chemotherapy without affecting normal cells. We tested VE-822, an ATR inhibitor, for in vitro and in vivo radiosensitization. Chk1 phosphorylation was used to indicate ATR activity, γH2AX and 53BP1 foci as evidence of DNA damage and Rad51 foci for homologous recombination activity. Sensitivity to radiation (XRT) and gemcitabine was measured with clonogenic assays in vitro and tumor growth delay in vivo. Murine intestinal damage was evaluated after abdominal XRT. VE-822 inhibited ATR in vitro and in vivo. VE-822 decreased maintenance of cell-cycle checkpoints, increased persistent DNA damage and decreased homologous recombination in irradiated cancer cells. VE-822 decreased survival of pancreatic cancer cells but not normal cells in response to XRT or gemcitabine. VE-822 markedly prolonged growth delay of pancreatic cancer xenografts after XRT and gemcitabine-based chemoradiation without augmenting normal cell or tissue toxicity. These findings support ATR inhibition as a promising new approach to improve the therapeutic ration of radiochemotherapy for patients with PDAC

External beam radiation therapy and enadenotucirev: inhibition of the DDR and mechanisms of radiation-mediated virus increase

Ionising radiation causes cell death through the induction of DNA damage, particularly double-stranded DNA (dsDNA) breaks. Evidence suggests that adenoviruses inhibit proteins involved in the DNA damage response (DDR) to prevent recognition of double-stranded viral DNA genomes as cellular dsDNA breaks. We hypothesise that combining adenovirus treatment with radiotherapy has the potential for enhancing tumour-specific cytotoxicity through inhibition of the DDR and augmentation of virus production. We show that EnAd, an Ad3/Ad11p chimeric oncolytic adenovirus currently being trialled in colorectal and other cancers, targets the DDR pathway at a number of junctures. Infection is associated with a decrease in irradiation-induced 53BP1 and Rad51 foci formation, and in total DNA ligase IV levels. We also demonstrate a radiation-associated increase in EnAd production in vitro and in a pilot in vivo experiment. Given the current limitations of in vitro techniques in assessing for synergy between these treatments, we adapted the plaque assay to allow monitoring of viral plaque size and growth and utilised the xCELLigence cell adhesion assay to measure cytotoxicity. Our study provides further evidence on the interaction between adenovirus and radiation in vitro and in vivo and suggests these have at least an additive, and possibly a synergistic, impact on cytotoxicity

APC loss affects DNA damage repair causing doxorubicin resistance in breast cancer cells

Chemoresistance is one of the leading causes of cancer-related deaths in the United States. Triple negative breast cancer (TNBC), a subtype lacking the known breast cancer receptors used for targeted therapy, is reliant on chemotherapy as the standard of care. The Adenomatous Polyposis Coli (APC) tumor suppressor is mutated or hypermethylated in 70% of sporadic breast cancers with APC-deficient tumors resembling the TNBC subtype. Using mammary tumor cells from the ApcMin/+ mouse model crossed to the Polyoma middle T antigen (PyMT) transgenic model, we previously showed that APC loss decreased sensitivity to doxorubicin (DOX). Understanding the molecular basis for chemoresistance is essential for the advancement of novel therapeutic approaches to ultimately improve patient outcomes. Resistance can be caused via different methods, but here we focus on the DNA repair response with DOX treatment. We show that MMTV-PyMT;ApcMin/+ cells have decreased DNA damage following 24 hour DOX treatment compared to MMTV-PyMT;Apc+/+ cells. This decreased damage is first observed 24 hours post-treatment and continues throughout 24 hours of drug recovery. Activation of DNA damage response pathways (ATM, Chk1, and Chk2) are decreased at 24 hours DOX-treatment in MMTV-PyMT;ApcMin/+ cells compared to control cells, but show activation at earlier time points. Using inhibitors that target DNA damage repair kinases (ATM, ATR, and DNA-PK), we showed that ATM and DNA-PK inhibition increased DOX-induced apoptosis in the MMTV-PyMT;ApcMin/+ cells. In the current work, we demonstrated that APC loss imparts resistance through decreased DNA damage response, which can be attenuated through DNA repair inhibition, suggesting the potential clinical use of DNA repair inhibitions as combination therapy

Small-molecule Polθ inhibitors provide safe and effective tumor radiosensitization in preclinical models

Purpose: DNA polymerase theta (Polθ, encoded by the POLQ gene) is a DNA repair enzyme critical for microhomology mediated end joining (MMEJ). Polθ has limited expression in normal tissues but is frequently overexpressed in cancer cells and, therefore, represents an ideal target for tumor-specific radiosensitization. In this study we evaluate whether targeting Polθ with novel small-molecule inhibitors is a feasible strategy to improve the efficacy of radiotherapy. Experimental Design: We characterized the response to Polθ inhibition in combination with ionizing radiation in different cancer cell models in vitro and in vivo. Results: Here, we show that ART558 and ART899, two novel and specific allosteric inhibitors of the Polθ DNA polymerase domain, potently radiosensitize tumor cells, particularly when combined with fractionated radiation. Importantly, noncancerous cells were not radiosensitized by Polθ inhibition. Mechanistically, we show that the radiosensitization caused by Polθ inhibition is most effective in replicating cells and is due to impaired DNA damage repair. We also show that radiosensitization is still effective under hypoxia, suggesting that these inhibitors may help overcome hypoxia-induced radioresistance. In addition, we describe for the first time ART899 and characterize it as a potent and specific Polθ inhibitor with improved metabolic stability. In vivo, the combination of Polθ inhibition using ART899 with fractionated radiation is well tolerated and results in a significant reduction in tumor growth compared with radiation alone. Conclusions: These results pave the way for future clinical trials of Polθ inhibitors in combination with radiotherapy

High density of peritumoral lymphatic vessels is a potential prognostic marker of endometrial carcinoma: a clinical immunohistochemical method study

<p>Abstract</p> <p>Background</p> <p>The lymphatic system is a major route for cancer cell dissemination and also a potential target for antitumor therapy. To investigate whether increased lymphatic vessel density (LVD) is a prognostic factor for nodal metastasis and survival, we studied peritumoral LVD (P-LVD) and intratumoral LVD (I-LVD) in samples from 102 patients with endometrial carcinoma;</p> <p>Methods</p> <p>Endometrial carcinoma tissues were analyzed for lymphatic vessels by immunohistochemical staining with an antibody against LYVE-1. Univariate analysis was performed with Kaplan-Meier life-table curves to estimate survival, and was compared using the log rank test. Prognostic models used multivariate Cox regression analysis for multivariate analyses of survival;</p> <p>Results</p> <p>Our study showed that P-LVD, but not I-LVD, was significantly correlated with lymph vascular space invasion (LVSI), lymph node metastasis, tumor stage, and CD44 expression in endometrial carcinoma. Moreover, P-LVD was an independent prognostic factor for progression-free survival and overall survival of endometrial carcinoma;</p> <p>Conclusions</p> <p>P-LVD may serve as a prognostic factor for endometrial carcinoma. The peritumoral lymphatics might play an important role in lymphatic vessel metastasis.</p

Towards screening Barrett’s Oesophagus: current guidelines, imaging modalities and future developments

Barrett’s oesophagus is the only known precursor to oesophageal adenocarcinoma (OAC). Although guidelines on the screening and surveillance exist in Barrett’s oesophagus, the current strategies are inadequate. Oesophagogastroduodenoscopy (OGD) is the gold standard method in screening for Barrett’s oesophagus. This invasive method is expensive with associated risks negating its use as a current screening tool for Barrett’s oesophagus. This review explores current definitions, epidemiology, biomarkers, surveillance, and screening in Barrett’s oesophagus. Imaging modalities applicable to this condition are discussed, in addition to future developments. There is an urgent need for an alternative non-invasive method of screening and/or surveillance which could be highly beneficial towards reducing waiting times, alleviating patient fears and reducing future costs in current healthcare services. Vibrational spectroscopy has been shown to be promising in categorising Barrett’s oesophagus through to high-grade dysplasia (HGD) and OAC. These techniques need further validation through multicentre trials