Mechanism of the induction of endoplasmic reticulum stress by the anti-cancer agent, di-2-pyridylketone 4,4-dimethyl-3-thiosemicarbazone (Dp44mT): activation of PERK/eIF2α, IRE1α, ATF6 and calmodulin kinase

The endoplasmic reticulum (ER) plays a major role in the synthesis, maturation and folding of proteins and is a critical calcium (Ca2+) reservoir. Cellular stresses lead to an overwhelming accumulation of misfolded proteins in the ER, leading to ER stress and the activation of the unfolded protein response (UPR). In the stressful tumor microenvironment, the UPR maintains ER homeostasis and enables tumor survival. Thus, a novel strategy for cancer therapeutics is to overcome chronically activated ER stress by triggering pro-apoptotic pathways of the UPR. Considering this, the mechanisms by which the novel anti-cancer agent, Dp44mT, can target the ER stress response pathways were investigated in multiple cell-types. Our results demonstrate that the cytotoxic chelator, Dp44mT, which forms redox-active metal complexes, significantly: (1) increased ER stress-associated pro-apoptotic signaling molecules (i.e., p-eIF2α, ATF4, CHOP); (2) increased IRE1α phosphorylation (p-IRE1α) and XBP1 mRNA splicing; (3) reduced expression of ER stress-associated cell survival signaling molecules (e.g., XBP1s and p58IPK); (4) increased cleavage of the transcription factor, ATF6, which enhances expression of its downstream targets (i.e., CHOP and BiP); and (5) increased phosphorylation of CaMKII that induces apoptosis. In contrast to Dp44mT, the iron chelator, DFO, which forms redox-inactive iron complexes, did not affect BiP, p-IRE1α, XBP1 or p58IPK levels. This study highlights the ability of a novel cancer therapeutic (i.e., Dp44mT) to target the pro-apoptotic functions of the UPR via cellular metal sequestration and redox stress. Assessment of ER stress-mediated apoptosis is fundamental to the understanding of the pharmacology of chelation for cancer treatment

Molecular Typing of Methicillin Resistant Staphylococcus aureus using coa Gene Polymerase Chain Reaction-Restriction Fragment Length Polymorphism: A Cross-sectional Study

Introduction: The need for fast, precise diagnostic tests to identify active tuberculosis is essential, mainly in endemic nations such as India. An automated real-time Polymerase Chain Reaction (PCR) method for pulmonary tuberculosis (TB) detection known as the Cartridge Based Nucleic Acid Amplification Test (CBNAAT) or GeneXpert assay shows great promise as a complement to the TrueNat and conventional sputum microscopy techniques. Aim: To compare sensitivity, specificity, Positive Predictive Value (PPV), and Negative Predictive Value (NPV) of CBNAAT with TrueNat and smear microscopy in the detection of Mycobacterium tuberculosis. Materials and Methods: A cross-sectional comparative study on 175 patients with suspected pulmonary TB was conducted from June 2021 to November 2021 in a tertiary care hospital at Government Medical College, Doda District of Jammu and Kashmir, India. The sensitivity, specificity, PPV, NPV, and diagnostic accuracy for the diagnosis of tuberculosis were calculated for Acid Fast Bacilli (AFB) smear microscopy, TrueNat, and the GeneXpert and compared with each other. Statistical analysis of the data was conducted with Statistical Package for the Social Science (SPSS) version 20.0. Results: Out of the total 175, 168 (96%) patients were TB positive by CBNAAT, 162 (92.6%) by TrueNat, and 148 (84.6%) as per smear microscopy. Sensitivity, specificity, PPV, NPV, and accuracy of Ziehl-Neelsen (ZN) stain in the detection of pulmonary TB in sputum samples were 86.31%, 57.14%, 97.97%, 14.81%, and 85.14%, respectively. Whereas in the case of the TrueNat technique sensitivity, specificity, PPV, NPV, and accuracy were 94.05%, 42.86%, 97.53%, 23.08%, and 92.00%, respectively. In the case of CBNAAT sensitivity, specificity, PPV, NPV, and accuracy in the detection of pulmonary TB in sputum samples were 97.02%, 28.57%, 97.02%, 28.57%, and 94.29%, respectively. Conclusion: In respiratory samples, CBNAAT is more sensitive than ZN smear microscopy and TrueNat. Positive CBNAAT, but TrueNat and AFB microscopy negative results should be read cautiously and be well correlated with the clinical and treatment history of the patien

Deviation From \Lambda CDM With Cosmic Strings Networks

In this work, we consider a network of cosmic strings to explain possible deviation from \Lambda CDM behaviour. We use different observational data to constrain the model and show that a small but non zero contribution from the string network is allowed by the observational data which can result in a reasonable departure from \Lambda CDM evolution. But by calculating the Bayesian Evidence, we show that the present data still strongly favour the concordance \Lambda CDM model irrespective of the choice of the prior.Comment: 15 Pages, Latex Style, 4 eps figures, Revised Version, Accepted for publication in European Physical Journal

Redox cycling metals: Pedaling their roles in metabolism and their use in the development of novel therapeutics

Essential metals, such as iron and copper, play a critical role in a plethora of cellular processes including cell growth and proliferation. However, concomitantly, excess of these metal ions in the body can have deleterious effects due to their ability to generate cytotoxic reactive oxygen species (ROS). Thus, the human body has evolved a very well-orchestrated metabolic system that keeps tight control on the levels of these metal ions. Considering their very high proliferation rate, cancer cells require a high abundance of these metals compared to their normal counterparts. Interestingly, new anti-cancer agents that take advantage of the sensitivity of cancer cells to metal sequestration and their susceptibility to ROS have been developed. These ligands can avidly bind metal ions to form redox active metal complexes, which lead to generation of cytotoxic ROS. Furthermore, these agents also act as potent metastasis suppressors due to their ability to up-regulate the metastasis suppressor gene, N-myc downstream regulated gene 1. This review discusses the importance of iron and copper in the metabolism and progression of cancer, how they can be exploited to target tumors and the clinical translation of novel anti-cancer chemotherapeutics

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Dinitrosyl Iron Complexes and their Role in Patho-physiological Conditions

Nitric oxide (•NO) is a small free radical known to play an important role in cancer. Inside the cell, one of its primary interactions occurs with iron and thiols leading to the formation of dinitrosyl iron complexes (DNIC). Formation of these complexes renders iron inactive towards the various physiological functions it performs. Recently, N-myc downstream regulated gene 1 (NDRG1), a well known metastasis suppressor gene, was shown to be up-regulated by iron chelation and hypoxia inducible factor 1 alpha (HIF-1α) stabilization. We also observed HIF-1α stabilization in cancer cells on exposure to •NO. Given the similarities between NDRG1 regulation and the actions of •NO in cancer cells, we hypothesized that exposure of nitric oxide to cells results in NDRG1 upregulation, in an iron dependent manner. We observed time (0-24 hours) and dose (0-1mM) dependent increase in NDRG1 expression at both mRNA and protein level in cancer cells treated with •NO. NDRG1 protein, once expressed, was stable for a prolonged period of time (~48hours). As protein is a functional product of the gene, these results show that NDRG1 could be a clinically significant target for nitric oxide. We observed that, •NO-mediated NDRG1 up-regulation was an iron dependent process, possibly via formation of DNIC. In addition, we observed ~50% decrease in migration/invasion potential without affecting the viability of cancer cells on exposure to •NO. In another set of studies, we examined the role of DNIC in iron mediated oxidative stress. We observed that cells treated with •NO were partially protected against ROS mediated cytotoxicity (H2O2 exposure). Furthermore, pretreatment with •NO markedly decreases the oxidative stress (proportional to •OH generation) induced by peroxide treatment. Nitric oxide concentrations at which we observe cytoprotective effects correlated with the concentration-dependent increase in DNIC formation. We observed that iron supplemented cells showed increased oxidative stress and cytotoxicity on peroxide treatment, and higher doses of •NO-donors were required to circumvent this toxicity. These results support the hypothesis that •NO can act as an antioxidant by its ability to sequester cellular iron. In conclusion, these results show a novel mechanism for nitric oxide mediated effects in a biological system. It also signifies the importance of DNIC in the intracellular environment

Emerging Role of Autophagy in the Development and Progression of Oral Squamous Cell Carcinoma

Autophagy is a cellular catabolic process, which is characterized by degradation of damaged proteins and organelles needed to supply the cell with essential nutrients. At basal levels, autophagy is important to maintain cellular homeostasis and development. It is also a stress responsive process that allows the cells to survive when subjected to stressful conditions such as nutrient deprivation. Autophagy has been implicated in many pathologies including cancer. It is well established that autophagy plays a dual role in different cancer types. There is emerging role of autophagy in oral squamous cell carcinoma (OSCC) development and progression. This review will focus on the role played by autophagy in relation to different aspects of cancer progression and discuss recent studies exploring the role of autophagy in OSCC. It will further discuss potential therapeutic approaches to target autophagy in OSCC

Duodenal Cytochrome b (DCYTB) in Iron Metabolism: An Update on Function and Regulation

Iron and ascorbate are vital cellular constituents in mammalian systems. The bulk-requirement for iron is during erythropoiesis leading to the generation of hemoglobin-containing erythrocytes. Additionally; both iron and ascorbate are required as co-factors in numerous metabolic reactions. Iron homeostasis is controlled at the level of uptake; rather than excretion. Accumulating evidence strongly suggests that in addition to the known ability of dietary ascorbate to enhance non-heme iron absorption in the gut; ascorbate regulates iron homeostasis. The involvement of ascorbate in dietary iron absorption extends beyond the direct chemical reduction of non-heme iron by dietary ascorbate. Among other activities; intra-enterocyte ascorbate appears to be involved in the provision of electrons to a family of trans-membrane redox enzymes; namely those of the cytochrome b561 class. These hemoproteins oxidize a pool of ascorbate on one side of the membrane in order to reduce an electron acceptor (e.g., non-heme iron) on the opposite side of the membrane. One member of this family; duodenal cytochrome b (DCYTB); may play an important role in ascorbate-dependent reduction of non-heme iron in the gut prior to uptake by ferrous-iron transporters. This review discusses the emerging relationship between cellular iron homeostasis; the emergent “IRP1-HIF2α axis”; DCYTB and ascorbate in relation to iron metabolism