Loss of PERK function promotes ferroptosis by downregulating SLC7A11 (System Xc⁻) in colorectal cancer.

Ferroptosis, a genetically and biochemically distinct form of programmed cell death, is characterised by an iron-dependent accumulation of lipid peroxides. Therapy-resistant tumor cells display vulnerability toward ferroptosis. Endoplasmic Reticulum (ER) stress and Unfolded Protein Response (UPR) play a critical role in cancer cells to become therapy resistant. Tweaking the balance of UPR to make cancer cells susceptible to ferroptotic cell death could be an attractive therapeutic strategy. To decipher the emerging contribution of ER stress in the ferroptotic process, we observe that ferroptosis inducer RSL3 promotes UPR (PERK, ATF6, and IRE1α), along with overexpression of cystine-glutamate transporter SLC7A11 (System Xc-). Exploring the role of a particular UPR arm in modulating SLC7A11 expression and subsequent ferroptosis, we notice that PERK is selectively critical in inducing ferroptosis in colorectal carcinoma. PERK inhibition reduces ATF4 expression and recruitment to the promoter of SLC7A11 and results in its downregulation. Loss of PERK function not only primes cancer cells for increased lipid peroxidation but also limits in vivo colorectal tumor growth, demonstrating active signs of ferroptotic cell death in situ. Further, by performing TCGA data mining and using colorectal cancer patient samples, we demonstrate that the expression of PERK and SLC7A11 is positively correlated. Overall, our experimental data indicate that PERK is a negative regulator of ferroptosis and loss of PERK function sensitizes colorectal cancer cells to ferroptosis. Therefore, small molecule PERK inhibitors hold huge promise as novel therapeutics and their potential can be harnessed against the apoptosis-resistant condition.

Inhibition of p21 activates Akt kinase to trigger ROS-induced autophagy and impacts on tumor growth rate.

Owing to its ability to induce cellular senescence, inhibit PCNA, and arrest cell division cycle by negatively regulating CDKs as well as being a primary target of p53, p21 is traditionally considered a tumor suppressor. Nonetheless, several reports in recent years demonstrated its pro-oncogenic activities such as apoptosis inhibition by cytosolic p21, stimulation of cell motility, and promoting assembly of cyclin D-CDK4/6 complex. These opposing effects of p21 on cell proliferation, supported by the observations of its inconsistent expression in human cancers, led to the emergence of the concept of "antagonistic duality" of p21 in cancer progression. Here we demonstrate that p21 negatively regulates basal autophagy at physiological concentration. Akt activation, upon p21 attenuation, driven ROS accumulation appears to be the major underlying mechanism in p21-mediated modulation of autophagy. We also find p21, as a physiological inhibitor of autophagy, to have oncogenic activity during early events of tumor development while its inhibition favors survival and growth of cancer cells in the established tumor. Our data, thereby, reveal the potential role of autophagy in antagonistic functional duality of p21 in cancer.

MiR-539-3p impairs osteogenesis by suppressing Wnt interaction with LRP-6 co-receptor and subsequent inhibition of Akap-3 signaling pathway.

X-linked hypophosphatemia (XLH), an inheritable form of rickets is caused due to mutation in Phex gene. Several factors are linked to the disease's aetiology, including non-coding RNA molecules (miRNAs), which are key post-transcriptional regulators of gene expression and play a significant role in osteoblast functions. MicroRNAs sequence analysis showed differentially regulated miRNAs in phex silenced osteoblast cells. In this article, we report miR-539-3p, an unidentified novel miRNA, in the functional regulation of osteoblast. MiR-539-3p overexpression impaired osteoblast differentiation. Target prediction algorithm and experimental confirmation by luciferase 3' UTR reporter assay identified LRP-6 as a direct target of miR-539-3p. Over expression of miR-539-3p in osteoblasts down regulated Wnt/beta catenin signaling components and deteriorated trabecular microarchitecture leading to decreased bone formation in ovariectomized (Ovx) mice. Additionally, biochemical bone resorption markers like CTx and Trap-5b were elevated in serum samples of mimic treated group, while, reverse effect was observed in anti-miR treated animals along with increased bone formation marker P1NP. Moreover, transcriptome analysis with miR-539-3p identified a novel uncharacterized Akap-3 gene in osteoblast cells, knock down of which resulted in downregulation of osteoblast differentiation markers at both transcriptional and translational level. Overall, our study for the first time reported the role of miR-539-3p in osteoblast functions and its downstream Akap-3 signalling in regulation of osteoblastogenesis.

Do disease prevalence and severity drive COVID-19 vaccine demand?

Large scale vaccination of population is widely accepted to be the key to recovery from the devastating economic and public health impacts of the COVID-19 pandemic. However, low uptake of vaccine has challenged vaccination efforts in many parts of the world. The paper explores the determinants of demand for COVID-19 vaccination - specifically, the prevalence dependence hypothesis - that identifies infection prevalence and mortality as the key drivers of individual preventive behavior against infectious diseases. Using daily disease tracking and vaccination data from 47 European countries the paper finds strong evidence that COVID-19 infection rate and mortality rate drive future vaccination uptake. Specifically, results from fixed effects models suggest that while lagged infection prevalence induce vaccination uptake by 0.18 to 0.24 percent, while the effect of lagged mortality is significantly larger, ranging between 1.10 to 1.53 percent. The results highlight the critical role of behavioral response to epidemiological outcomes and are of critical significance for COVID-19 mitigation policies, especially as they relate to achieving vaccine-induced herd immunity and economic reopening.

Electrical Low-Frequency 1/fγ Noise Due to Surface Diffusion of Scatterers on an Ultra-low-Noise Graphene Platform.

Low-frequency 1/f γ noise is ubiquitous, even in high-end electronic devices. Recently, it was found that adsorbed O2 molecules provide the dominant contribution to flux noise in superconducting quantum interference devices. To clarify the basic principles of such adsorbate noise, we have investigated low-frequency noise, while the mobility of surface adsorbates is varied by temperature. We measured low-frequency current noise in suspended monolayer graphene Corbino samples under the influence of adsorbed Ne atoms. Owing to the extremely small intrinsic noise of suspended graphene, we could resolve a combination of 1/f γ and Lorentzian noise induced by the presence of Ne. We find that the 1/f γ noise is caused by surface diffusion of Ne atoms and by temporary formation of few-Ne-atom clusters. Our results support the idea that clustering dynamics of defects is relevant for understanding of 1/f noise in metallic systems.

Do parental preferences predict engagement in child health programs?

We evaluate the role of behavioral attributes in predicting engagement in an intervention program. Distinct from the previous studies, we investigate how parental preferences influence their engagement behavior in a health program when the targeted outcomes relate to the health of their children, as opposed to their own. We use an artifactual field experiment where the participants were former parent enrollees in a child health management program in Australia. Our findings suggest that parents' time preference and risk tolerance are robust predictors of engagement, measured by program attendance. Attendance is positively associated with patience and risk tolerance in the health domain, after controlling for a host of personality traits and socioeconomic factors. By improving our understanding of the behavioral risk factors for attrition, these findings offer important insights for enhancing participant engagement in intervention programs that are beset with the problem of high attrition.

Assessing mortality risk attributable to high ambient temperatures in Ahmedabad, 1987 to 2017.

BACKGROUND: Studies on high temperatures and mortality have not focused on underdeveloped tropical regions and have reported the associations of different temperature metrics without conducting model selection. METHODS: We collected daily mortality and meteorological data including ambient temperatures and humidity in Ahmedabad during summer, 1987-2017. We proposed two cross-validation (CV) approaches to compare semiparametric quasi-Poisson models with different temperature metrics and heat wave definitions. Using the fittest model, we estimated heat-mortality associations among general population and subpopulations. We also conducted separate analyses for 1987-2002 and 2003-2017 to evaluate temporal heterogeneity. FINDINGS: The model with maximum and minimum temperatures and without heat wave indicator gave the best performance. With this model, we found a substantial and significant increase in mortality rate starting from maximum temperature at 42 °C and from minimum temperature at 28 °C: 1 °C increase in maximum and minimum temperatures at lag 0 were associated with 9.56% (95% confidence interval [CI]: 6.64%, 12.56%) and 9.82% (95% CI: 6.33%, 13.42%) increase in mortality risk, respectively. People aged ≥65 years and lived in South residential zone where most slums were located, were more vulnerable. We observed flatter increases in mortality risk associated with high temperatures comparing the period of 2003-2017 to 1987-2002. INTERPRETATION: The analyses provided better understanding of the relationship of high temperatures with mortality in underdeveloped tropical regions and important implications in developing heat warning system for local government. The proposed CV approaches will benefit future scientific work.

CXCR4 intracellular protein promotes drug resistance and tumorigenic potential by inversely regulating the expression of Death Receptor 5.

Chemokine receptor CXCR4 overexpression in solid tumors has been strongly associated with poor prognosis and adverse clinical outcome. However, blockade of CXCL12-CXCR4 signaling axis by inhibitors like Nox-A12, FDA approved CXCR4 inhibitor drug AMD3100 have shown limited clinical success in cancer treatment. Therefore, exclusive contribution of CXCR4-CXCL12 signaling in pro-tumorigenic function is questionable. In our pursuit to understand the impact of chemokine signaling in carcinogenesis, we reveal that instead of CXCR4-CXCL12 signaling, presence of CXCR4 intracellular protein augments paclitaxel resistance and pro-tumorigenic functions. In search of pro-apoptotic mechanisms for CXCR4 mediated drug resistance; we discover that DR5 is a new selective target of CXCR4 in breast and colon cancer. Further, we detect that CXCR4 directs the differential recruitment of transcription factors p53 and YY1 to the promoter of DR5 in course of its transcriptional repression. Remarkably, inhibiting CXCR4-ligand-mediated signals completely fails to block the above phenotype. Overexpression of different mutant versions of CXCR4 lacking signal transduction capabilities also result in marked downregulation of DR5 expression in colon cancer indeed confirms the reverse relationship between DR5 and intracellular CXCR4 protein expression. Irrespective of CXCR4 surface expression, by utilizing stable gain and loss of function approaches, we observe that intracellular CXCR4 protein selectively resists and sensitizes colon cancer cells against paclitaxel therapy in vitro and in vivo. Finally, performing TCGA data mining and using human breast cancer patient samples, we demonstrate that expression of CXCR4 and DR5 are inversely regulated. Together, our data suggest that targeting CXCR4 intracellular protein may be critical to dampen the pro-tumorigenic functions of CXCR4.

Facile synthesis of rapamycin-peptide conjugates as mTOR and Akt inhibitors.

A simple and straightforward process for the synthesis of rapamycin peptide conjugates in a regio and chemoselective manner was developed. The methodology comprises the tagging of chemoselective functionalities to rapamycin and peptides which enables the conjugation of free peptides, without protecting the functionality of the side chain amino acids, in high yield and purity. From this methodology, we successfully conjugate free peptides containing up to 15 amino acids. Rapamycin is also conjugated to the peptides known for inhibiting the kinase activity of Akt protein. These conjugates act as dual target inhibitors and inhibit the kinase activity of both mTOR and Akt.

Salinomycin inhibits epigenetic modulator EZH2 to enhance death receptors in colon cancer stem cells.

Drug resistance is one of the trademark features of Cancer Stem Cells (CSCs). We and others have recently shown that paucity of functional death receptors (DR4/5) on the cell surface of tumour cells is one of the major reasons for drug resistance, but their involvement in the context of in CSCs is poorly understood. By harnessing CSC specific cytotoxic function of salinomycin, we discovered a critical role of epigenetic modulator EZH2 in regulating the expression of DRs in colon CSCs. Our unbiased proteome profiler array approach followed by ChIP analysis of salinomycin treated cells indicated that the expression of DRs, especially DR4 is epigenetically repressed in colon CSCs. Concurrently, EZH2 knockdown demonstrated increased expression of DR4/DR5, significant reduction of CSC phenotypes such as spheroid formation in-vitro and tumorigenic potential in-vivo in colon cancer. TCGA data analysis of human colon cancer clinical samples shows strong inverse correlation between EZH2 and DR4. Taken together, this study provides an insight about epigenetic regulation of DR4 in colon CSCs and advocates that drug-resistant colon cancer can be therapeutically targeted by combining TRAIL and small molecule EZH2 inhibitors.

Infectivity, virulence, pathogenicity, host-pathogen interactions of SARS and SARS-CoV-2 in experimental animals: a systematic review.

The outbreak of the SARS-CoV-2 in mainland China with subsequent human to human transmission worldwide had taken up the shape of a devastating pandemic. The ability of the virus to infect multiple species other than humans has currently been reported in experimental conditions. Non-human primates, felines, ferrets, rodents and host of other animals could previously be infected in experimental conditions with SARS-CoV and recently with SARS-CoV-2, both virus using Angiotensin-converting-enzyme 2 receptor for cellular entry. The variations in sequence homology of ACE2 receptor across species is identified as one of the factors determining virulence and pathogenicity in animals. The infection in experimental animals with SARS-CoV or SARS-CoV-2 on most occasions are asymptomatic, however, the virus could multiply within the respiratory tract and extra-pulmonary organs in most of the species. Here, we discuss about the pathogenicity, transmission, variations in angiotensin-converting-enzyme 2 receptor-binding across species and host pathogen interactions of SARS and SARS-CoV-2 in laboratory animals used in research.

Gedunin isolated from the mangrove plant Xylocarpus granatum exerts its anti-proliferative activity in ovarian cancer cells through G2/M-phase arrest and oxidative stress-mediated intrinsic apoptosis.

Gedunin is a natural tetranorterpenoid secondary metabolite found in plants of the Meliaceae family, which has been reported for its antiparasitic, antifungal and anticancer activities. Here, we describe the molecular mechanisms underlying the in vitro anti proliferative activity of gedunin (isolated from the mangrove plant Xylocarpus granatum) in human ovarian cancer cells. We observed that gedunin triggered severe ROS generation leading to DNA damage and cell cycle arrest in G2/M phase thus inhibiting cell proliferation. ROS upregulation also led to mitochondrial stress and membrane depolarization, which eventually resulted in mitochondria-mediated apoptosis following cytochrome C release, caspase 9, 3 activation, and PARP cleavage. Transmission electron microscopy of gedunin treated cells revealed sub-cellular features typical of apoptosis. Moreover, an upregulation in stress kinases like phospho-ERK 1/2, phospho-p38 and phospho-JNK was also observed in gedunin treated cells. Free radical scavenger N-Acetyl-L-Cysteine (NAC) reversed all these effects resulting in increased cell survival, abrogation of cell cycle arrest, rescue of mitochondrial membrane potential and suppression of apoptotic markers. Interestingly, gedunin is also an inhibitor of the evolutionarily conserved molecular chaperone Heat Shock Protein 90 (hsp90) responsible for maintaining cellular homeostasis. Targeting this chaperone could be an attractive strategy for developing cancer therapeutics since many oncogenic proteins are also client proteins of hsp90. Collectively, our findings provide insights into the molecular mechanism of action of gedunin, which may aid drug development efforts against ovarian cancer.

Microtubule disrupting agent-mediated inhibition of cancer cell growth is associated with blockade of autophagic flux and simultaneous induction of apoptosis.

OBJECTIVES: Given that autophagy inhibition is a feasible way to enhance sensitivity of cancer cells towards chemotherapeutic agents, identifying potent autophagy inhibitor has obvious clinical relevance. Here, we investigated ability of TN-16, a microtubule disrupting agent, on modulation of autophagic flux and its significance in promoting in vitro and in vivo cancer cell death. MATERIALS AND METHODS: The effect of TN-16 on cancer cell proliferation, cell division, autophagic process and apoptotic signalling was assessed by various biochemical (Western blot and SRB assay), morphological (TEM, SEM, confocal microscopy) and flowcytometric assays. In vivo anti-tumour efficacy of TN-16 was investigated in syngeneic mouse model of breast cancer. RESULTS: TN-16 inhibited cancer cell proliferation by impairing late-stage autophagy and induction of apoptosis. Inhibition of autophagic flux was demonstrated by accumulation of autophagy-specific substrate p62 and lack of additional LC3-II turnover in the presence of lysosomotropic agent. The effect was validated by confocal micrographs showing diminished autophagosome-lysosome fusion. Further studies revealed that TN-16-mediated inhibition of autophagic flux promotes apoptotic cell death. Consistent with in vitro data, results of our in vivo study revealed that TN-16-mediated tumour growth suppression is associated with blockade of autophagic flux and enhanced apoptosis. CONCLUSIONS: Our data signify that TN-16 is a potent autophagy flux inhibitor and might be suitable for (pre-) clinical use as standard inhibitor of autophagy with anti-cancer activity.

Occupational variation in the relationship between child health and family size.

Empirical evidence for quantity-quality trade-off is hardly ubiquitous, especially when quality is measured by child health outcomes. The paper offers a new explanation to this puzzle. It shows that the quantity-quality relationships are subject to occupational variation when quality is given by nutritional status, and occupations differ in their physical labor intensity. It embeds, in a simple household optimization model, a minimum consumption requirement that rises with physical work intensity of occupation. The occupational differences in subsistence consumption requirement generate variation in child nutritional status, and hence, in the shadow price of children. The nature of the quantity-quality relationship, therefore, varies with work intensity of occupations. The model yields an equilibrium relationship between the number and nutritional status of children that is positive for households in strenuous occupations and ambiguous for other households. These results help reconcile some inconsistent findings on quantity-quality trade-off, which may partly be explained by the omission of occupational variation in nutritional status.

3-Arylindanones and related compounds as antiproliferative agents against colorectal cancer.

Diverse benzylidene indanones and their derivatives were synthesized as anticancer agents. Two of the analogues, that is 7 and 22, exhibited significant antiproliferative activity against several human cancer cell lines. Both the compounds possessed antimitotic activity and induced apoptosis in DLD1 colorectal adenocarcinoma cells through activation of caspase pathways. In cell cycle analysis, both the compounds induced predominantly G2/M phase arrest in DLD1 cells. Molecular docking studies revealed that compound 7 occupies colchicine binding pocket of ß-tubulin. Both the compounds were safe in acute oral toxicity in rodents. Both the compounds are further being optimized for better efficacy.

7-hydroxyfrullanolide, isolated from Sphaeranthus indicus, inhibits colorectal cancer cell growth by p53-dependent and -independent mechanism.

Sphaeranthus indicus Linn. is commonly used in Indian traditional medicine for management of multiple pathological conditions. However, there are limited studies on anticancer activity of this plant and its underlying molecular mechanisms. Here, we isolated an active constituent, 7-hydroxyfrullanolide (7-HF), from the flowers of this plant, which showed promising chemotherapeutic potential. The compound was more effective in inhibiting in vitro proliferation of colon cancers cells through G2/M phase arrest than other cancer cell lines that were used in this study. Consistent with in vitro data, 7-HF caused substantial regression of tumour volume in a syngeneic mouse model of colon cancer. The molecule triggered extrinsic apoptotic pathway, which was evident as upregulation of DR4 and DR5 expression as well as induction of their downstream effector molecules (FADD, Caspase-8). Concurrent activation of intrinsic pathway was demonstrated with loss of ΔΨm to release pro-apoptotic cytochrome c from mitochondria and activation of downstream caspase cascades (Caspase -9, -3). Loss of p53 resulted in decreased sensitivity of cells towards pro-apoptotic effect of 7-HF with increased number of viable cells indicating p53-dependent arrest of cancer cell growth. This notion was further supported with 7-HF-mediated elevation of endogenous p53 level, decreased expression of MDM2 and transcriptional upregulation of p53 target genes in apoptotic pathway. However, 7-HF was equally effective in preventing progression of HCT116 p53+/+ and p53-/- cell derived xenografts in nude mice, which suggests that differences in p53 status may not influence its in vivo efficacy. Taken together, our results support 7-HF as a potential chemotherapeutic agent and provided a new mechanistic insight into its anticancer activity.

Building Resilience to Climate Change: Pilot Evaluation of the Impact of India's First Heat Action Plan on All-Cause Mortality.

Background: Ahmedabad implemented South Asia's first heat action plan (HAP) after a 2010 heatwave. This study evaluates the HAP's impact on all-cause mortality in 2014-2015 relative to a 2007-2010 baseline. Methods: We analyzed daily maximum temperature (T max)-mortality relationships before and after HAP. We estimated rate ratios (RRs) for daily mortality using distributed lag nonlinear models and mortality incidence rates (IRs) for HAP warning days, comparing pre- and post-HAP periods, and calculated incidence rate ratios (IRRs). We estimated the number of deaths avoided after HAP implementation using pre- and post-HAP IRs. Results: The maximum pre-HAP RR was 2.34 (95%CI 1.98-2.76) at 47°C (lag 0), and the maximum post-HAP RR was 1.25 (1.02-1.53) estimated at 47°C (lag 0). Post-to-pre-HAP nonlagged mortality IRR for T max over 40°C was 0.95 (0.73-1.22) and 0.73 (0.29-1.81) for T max over 45°C. An estimated 1,190 (95%CI 162-2,218) average annualized deaths were avoided in the post-HAP period. Conclusion: Extreme heat and HAP warnings after implementation were associated with decreased summertime all-cause mortality rates, with largest declines at highest temperatures. Ahmedabad's plan can serve as a guide for other cities attempting to increase resilience to extreme heat.

Antiproliferative efficacy of curcumin mimics through microtubule destabilization.

Curcumin possesses an attractive chemical structure with highly conjugated diferuloylmethane core. Curcumin mimics have been designed and prepared with an additional bridged phenyl ring in conjugation. Fourteen diverse analogues were evaluated against a panel of human cancer cell lines. The best analogue of the series i.e. compound 6a exhibited potent cytotoxicity against A431, epidermoid carcinoma cell line (IC50 = 1.5 µM) and DLD1, colorectal adenocarcinoma cell line (IC50 = 6.9 µM). In tubulin kinetics experiment, compound 6a destabilized polymerisation process (IC50 = 4.68 µM). In cell cycle analysis, compound 6a exerted G2/M phase arrest in A431 cells and induced apoptosis. In Ehrlich Ascites Carcinoma in Swiss-albino mice, compound 6a showed 78.6% tumour reduction at 80 mg/kg dose and 57% solid tumour reduction at 150 mg/kg dose. Further, in acute-oral toxicity experiment in rodent model, compound 6a was given in three different oral doses to Swiss albino mice. There were non-significant changes in various biochemical parameters and major body organs studied, including their absolute and relative weights. It was tolerable up to 300 mg/kg dose in Swiss-albino mice. The present study shows that the novel curcumin mimic 6a is a safe and efficacious anticancer compound. However, it needs to be optimized for better efficacy.

Ormeloxifene-induced unfolded protein response contributes to autophagy-associated apoptosis via disruption of Akt/mTOR and activation of JNK.

Autophagy, a regulated nutrient recycling program can affect both cell survival and cell death. Here, we show that Ormeloxifene (ORM), a selective estrogen receptor modulator approved for oral contraceptive use induces autophagic flux in ovarian cancer cells, which is activated by an ER stress response upstream of autophagy. The ER stress response is characterized by activation of IRE1α, PERK and ATF6 and is under regulation of JNK. Pharmacological inhibition of either autophagy or ER stress increased cell survival, as did silencing of autophagy proteins LC3 and Beclin 1, implying that ORM-induced autophagy is pro-death in nature. Ultrastructural observations of treated cells confirmed stages of autophagic maturation. Caspase-dependent apoptosis succeeded these events and was characterized by generation of reactive oxygen species and disruption of mitochondrial membrane potential. A concomitant inhibition of the Akt/mTOR axis was also observed with possible regulation of Akt by ORM. ORM inhibited tumor growth in ovarian xenograft model and displayed autophagic activity. In summary, in vitro and in vivo results reveal that ORM induces autophagy-associated cell death to attenuate proliferation of ovarian cancer cells. Our results demonstrate that using ORM in combination with ER stress and autophagy modulators could offer better therapeutic outcome in ovarian cancer.

Synthesis, SAR and biological studies of sugar amino acid-based almiramide analogues: N-methylation leads the way.

Leishmaniasis, caused by the protozoan parasites of the genus Leishmania, is one of the most neglected diseases endemic in many continents posing enormous global health threats and therefore the discovery of new antileishmanial compounds is of utmost urgency. The antileishmanial activities of a library of sugar amino acid-based linear lipopeptide analogues were examined with the aim to identify potential drug candidates to treat visceral leishmaniasis. It was found that among the synthesized analogues, most of the permethylated compounds exhibited more activity in in vitro studies against intra-macrophagic amastigotes than the non-methylated analogues. SAR and NMR studies revealed that introduction of the N-methyl groups inhibited the formation of any turn structure in these molecules, which led to their improved activities.