Biology subjects

Kumar, S.

Publications and source records attributed to Kumar, S..

At least 361 records · Page 20Linked to original sources

bioRxiv2023

Multi-omic screening of invasive GBM cells in engineered biomaterials and patient biopsies reveals targetable transsulfuration pathway alterations

While the poor prognosis of glioblastoma arises from the invasion of a subset of tumor cells, little is known of the metabolic alterations within these cells that fuel invasion. We integrated spatially addressable hydrogel biomaterial platforms, patient site-directed biopsies, and multi-omics analyses to define metabolic drivers of invasive glioblastoma cells. Metabolomics and lipidomics revealed elevations in the redox buffers cystathionine, hexosylceramides, and glucosyl ceramides in the invasive front of both hydrogel-cultured tumors and patient site-directed biopsies, with immunofluorescence indicating elevated reactive oxygen species (ROS) markers in invasive cells. Transcriptomics confirmed upregulation of ROS-producing and response genes at the invasive front in both hydrogel models and patient tumors. Amongst oncologic ROS, hydrogen peroxide specifically promoted glioblastoma invasion in 3D hydrogel spheroid cultures. A CRISPR metabolic gene screen revealed cystathionine gamma lyase (CTH), which converts cystathionine to the non-essential amino acid cysteine in the transsulfuration pathway, to be essential for glioblastoma invasion. Correspondingly, supplementing CTH knockdown cells with exogenous cysteine rescued invasion. Pharmacologic CTH inhibition suppressed glioblastoma invasion, while CTH knockdown slowed glioblastoma invasion in vivo. Our studies highlight the importance of ROS metabolism in invasive glioblastoma cells and support further exploration of the transsulfuration pathway as a mechanistic and therapeutic target.

cancer biology↗

bioRxiv2023

Determination of oligomeric organization of membrane proteins from native membranes at nanoscale-spatial and single-molecule resolution

The oligomeric organization of membrane proteins in native cell membranes is a critical regulator of their function. High-resolution quantitative measurements of oligomeric assemblies and how they change under different conditions are indispensable to the understanding of membrane protein biology. We report a single-molecule imaging technique (Native-nanoBleach) to determine the oligomeric distribution of membrane proteins directly from native membranes at an effective spatial resolution of [~]10 nm. We achieved this by capturing target membrane proteins in "native nanodiscs" with their proximal native membrane environment using amphipathic copolymers. We established this method using structurally and functionally diverse membrane proteins with well-established stoichiometries. We then applied Native-nanoBleach to quantify the oligomerization status of a receptor tyrosine kinase (TrkA) and a small GTPase (KRas) under conditions of growth-factor binding or oncogenic mutations, respectively. Native-nanoBleach provides a sensitive, single-molecule platform to quantify membrane protein oligomeric distributions in native membranes at an unprecedented spatial resolution.

biophysics↗

bioRxiv2023

Exploiting heterogeneity in coupled, two plasmid systems for dynamic population adaptation

In synthetic multi-plasmid systems, it is standard to use only plasmids with orthogonal replication mechanisms to avoid phenotypic heterogeneity and ensure plasmid stability. In nature, however, microbial populations actively exploit heterogeneity to survive in fluctuating environments. Here we show that the intentional use of distinct plasmids with identical origins of replication (oris) can help an engineered bacterial population adapt to its environment. We find that copy number coupling between distinct plasmids in such systems allows for copy number buffering of an essential, but high-burden construct through the action of a stably maintained, nonessential plasmid. Plasmid coupling also generates population state memory without additional layers of regulatory control. This work reimagines how we design synthetic populations to survive and adapt by strategically giving control back to the cells.

synthetic biology↗

bioRxiv2023

Artificial Intelligence uncovers Evolutionarily Conserved Intracellular Allosteric Modulators of GPCR-Gα interface.

Endogenous intracellular allosteric modulators of GPCRs remain largely unexplored, with limited binding and phenotype data available. This gap arises from the lack of robust computational methods for unbiased cavity identification, cavity-specific ligand design, synthesis, and validation across GPCR topology. Here, we developed Gcoupler, an AI-driven generalized computational toolkit that leverages an integrative approach combining de novo ligand design, statistical methods, Graph Neural Networks, and Bioactivity-based ligand prioritization for rationally predicting high-affinity ligands. Using Gcoupler, we interrogated intracellular metabolites that target and regulate the GPCR-G interface (Ste2p-Gpa1p), affecting pheromone-induced programmed cell death in yeast. Our computational analysis, complemented by experimental validations, including genetic screening, multi-omics, site-directed mutagenesis, biochemical assays, and physiological readouts, identified endogenous hydrophobic metabolites, notably sterols, as direct intracellular allosteric modulators of Ste2p. Molecular simulations coupled with biochemical signaling assessment in site-directed Ste2p mutants further confirmed that metabolites binding to GPCR-G obstruct downstream signaling, possibly via a cohesive effect. Finally, by utilizing isoproterenol-induced, GPCR-mediated human and neonatal rat cardiac hypertrophy models, we observed that elevated metabolite levels attenuate hypertrophic response, reinforcing the evolutionary relevance of this mechanism.

bioinformatics↗

bioRxiv2023

Mass spectrometric analysis and biostimulatory effects of boar seminal gel, saliva and semen in pigs

The present study aimed to identify novel biostimulatory compounds in boar seminal gel (SG), saliva and semen using Gas chromatography-mass spectrometry (GC-MS). SG alone and its combined application with saliva (SG+saliva) and semen (SG+semen) also studied to train young boars. SG alone and SG+Saliva investigated for estrus induction in gilts and sows. Distilled water (DW) exposure was kept as control. SG, saliva and semen screened for total 105, 96 and 89 compounds. The highest concentration was of alkanes followed by sugar alcohols, then hydrocarbons, amino acids and fatty acids. Elaidic acid is the novel compound identified in pigs. Other compounds were tridecenol, undecane, hexadecone, eicosane, tetracosane etc. Further, young males (64.86%) were able to get trained. Significant higher (p<0.05) number of males got trained in exposure to SG (80%), SG+saliva (75%) and SG+semen (75%) than control. The time (hrs) taken by young boars to get trained on exposure to combination of SG+saliva (244{+/-}22.19) and SG+semen (216{+/-}13.14) was lesser (p<0.05) than SG (356{+/-}61.85) alone. Interval (hrs) for exhibition of different sexual behaviour by males on exposure to SG, saliva and semen was lesser (p<0.05) than control. Estrus was induced in 61.25% of females. Significant (p<0.05) higher number of females showed estrus response to exposure of SG (72.72%) and SG+saliva (69.23%) than control. Interval taken to exhibit estrus was lesser (p<0.05) in females exposed to SG+saliva (201.88{+/-}12.66) than SG (262.14{+/-}20.06) alone. Interval (hrs) for exhibition of different sexual behaviour by females on exposure to SG+saliva was lesser (p<0.05) than control. In conclusion, novel compounds with biostimulatory properties have been identified in boar SG, saliva and semen. The combined exposure of SG with saliva and semen have more intense biostimulation effect than SG alone. Such compounds and biostimulatory effects can be exploited for augmenting reproductive efficiency in pigs.

animal behavior and cognition↗

bioRxiv2023

Omega 3 fish oil suppress radiation induced hepato and renal toxicity in mice through modulation in Wnt canonical pathway combined with NHEJ and Intrinsic Apoptotic pathway

Radiation is associated with inflammation and oxidative stress, the latter of which contributes to activation of DNA damage and apoptosis. Omega 3 polyunsaturated fatty acids (PUFAs) have been reported to limit oxidative stress and DNA damage. The aim of this study was to evaluate the effect of the Omega 3 PUFA on antioxidant defence in male physiology on mice model. Liver and kidney tissues were obtained from whole body irradiated mice divided under 9 groups (Weight-10mg, 6-8 months old, n=5) and age-matched male controls (6-8 months old, n=5). 6 groups have been orally intubated with (50, 100 and 150) mg/kg BW with Omega 3 fish oil 1hr prior to the radiation exposure. Liver and kidney were surgically obtained after 24 hours and 30 days of radiation exposure. Omega 3 fish oil supplementation increased the level of mRNA expression of Lef1, Axin2, Survivin, Ku70, SOD1, SOD2, Cat, iNOS and decresed the level of Bax and Bcl2 in irradiated with omega 3 fish oil supplementation compare to irradiated alone. Omega 3 fish oil increased SOD scavenging, Catalase, Nitric oxide scavenging activity, Total antioxidant capacity and decrease the lipid peroxidation. The improvements in mRNA level of candidate genes of Wnt canonical pathway, NHEJ pathway, oxidative stress status serve as a stimulus for further investigation of Omega 3 fish oil as supplementation for patients undergo radiation therapy.

pharmacology and toxicology↗

bioRxiv2023

Hormonal Interventions for optimizing reproductive efficiency in pigs at Farmers field

ObjectiveOptimizing reproductive efficiency in terms of estrus induction and production performance using simplified hormonal intervention using GnRH, gonadotropins and progesterone at farmers field conditions to bred animals with superior quality semen and also to reduce the maintenance cost. MethodThe present study was planned for optimizing reproductive efficiency using four different easily available hormonal agents with simplified protocols at farmers field. A total of 126 females were used in the study. Hormonal protocols I, II, III and IV using GnRH + (PMSG+ hCG), (PMSG+ hCG), PMSG alone and prepared progesterone gel respectively were used for estrus induction in gilts and sows. ResultsThe estrus induction/rate was (77.77%, 81.36%, 78.57% and 50% respectively. The corresponding figures for interval (hrs) of heat exhibition from hormonal administration (121.33{+/-}4.93, 121.54{+/-}3.60, 78.52{+/-}4.52 and 192{+/-}24), conception rate (%) (72.22%, 81.25%, 68.18% and 33.33%) farrowing rate (55.55%, 68.29%, 68.18% and 33.33 %), total litter size at birth (7.2{+/-}0.64, 7.90{+/-}0.47, 8.90{+/-}0.47 and 7.00{+/-}0) and hormonal cost (Rs.) per animal (570, 335, 280 and 250 Rs.) were respectively. The easier to use protocol was III followed by II, I and IV. ConclusionIt was found that protocol II and III are effective and easier so can be used for optimizing reproductive efficiency in pigs at farmers field.

physiology↗

bioRxiv2023

Metagenomic analysis of Pigs' faecal microbiome and its functional response associated with dietary fibre

Pig husbandry is the most valued and economically sustainable husbandry in the livestock farming system. The performance and productivity of the pig are chiefly dependent on the nutritional factor steered by gut beneficial bacteria. The swine gut microbiome has a direct relationship with feed efficiency. As a consequence, identifying microbial taxonomy and functional capacity is critical for proper nutrient digestion. In the present investigation, eighteen grower pigs aged 3 months and weighing 30{+/-}0.55 kg were allocated into three different groups using a randomized block layout and supplemented with QPM maize fodder of 0, 5, and 10% to the basal diet by substituting (wt/wt on DM) the maize grains, and named as T0, T1, and T2 to probe the increase in gut beneficial bacteria found in the faecal contents. For comparison with T0, T1, and T2, a random faecal sample designated R was collected from six grower pigs of the same age group and bodyweight fed a maize-soya bean-based diet. The experiment is being carried out to investigate the effect of various maize fodder levels on the metagenomic profiles of pig gut microbiota using the 16S rRNA gene. All of the experimental diets were iso-nitrogenous, with protein content ranging from 18.37 to 18.63 per cent. The data generated by 16S rRNA amplicon analysis was 68, 56, 61, and 39 Mb in R, T0, T1, and T2 samples, respectively. From taxonomic distribution, bacterial phyla namely Firmicutes, Bacteroidetes, Proteobacteria, and Spirochetes are found in descending order of relative abundance in the R, T0, and T1 groups, respectively, while Spirochaetes, Proteobacteria, Fibrobacteres, Bacteroidetes, and Firmicutesare found in descending order of relative abundance in the T2 group. The relative profusion of Fibrobacter succinogenes is 0.89% and 16.84% in the T1 and T2 groups. According to the findings, a higher level of maize fodder in the diet of grower pigs promotes the growth of fibre-degrading bacteria in the gut microbiota, particularly Fibrobacter succinogenes. Moreover, feeding green maize has decreased the population of methanobacteria in the gut of pigs, which in turn has limited the production of methane.

genomics↗

bioRxiv2023

Anteromedial Thalamus Gates the Selection & Stabilization of Long-Term Memories

Memories initially formed in hippocampus gradually stabilize to cortex, over weeks-to-months, for long-term storage. The mechanistic details of this brain re-organization process remain poorly understood. In this study, we developed a virtual-reality based behavioral task and observed neural activity patterns associated with memory reorganization and stabilization over weeks-long timescales. Initial photometry recordings in circuits that link hippocampus and cortex revealed a unique and prominent neural correlate of memory in anterior thalamus that emerged in training and persisted for several weeks. Inhibition of the anteromedial thalamus-to-anterior cingulate cortex projections during training resulted in substantial memory consolidation deficits, and gain amplification more strikingly, was sufficient to enhance consolidation of otherwise unconsolidated memories. To provide mechanistic insights, we developed a new behavioral task where mice form two memories, of which only the more salient memory is consolidated, and also a technology for simultaneous and longitudinal cellular resolution imaging of hippocampus, thalamus, and cortex throughout the consolidation window. We found that whereas hippocampus equally encodes multiple memories, the anteromedial thalamus forms preferential tuning to salient memories, and establishes inter-regional correlations with cortex, that are critical for synchronizing and stabilizing cortical representations at remote time. Indeed, inhibition of this thalamo-cortical circuit while imaging in cortex reveals loss of contextual tuning and ensemble synchrony in anterior cingulate, together with behavioral deficits in remote memory retrieval. We thus identify a thalamo-cortical circuit that gates memory consolidation and propose a mechanism suitable for the selection and stabilization of hippocampal memories into longer term cortical storage.

neuroscience↗

bioRxiv2023

Development and qualification of a high-yield recombinant human Erythropoietin biosimilar

Recombinant human erythropoietin (rhEPO) has been saving millions of lives worldwide as a potent and safe treatment for the lack of erythrocyte, which is caused by chronic kidney disease (CKD) and other issues. Several biosimilars of rhEPO have been approved since the expiry of the relevant patents to provide cost-effective options but the price of rhEPO is still high for the affordability of global community. Therefore, development of biosimilar of rhEPO at a lower price is highly necessary. Here we report the development and characterization of a biosimilar of rhEPO with high-yield satisfying regulatory requirements. The hEPO-expressing cDNA was stably expressed in CHO cells with successive transfection. The master cell bank (MCB) and working cell bank (WCB) were established from the best selected clone and characterized for 50 passages. The rhEPO was expressed from the WCB in single-use suspension culture system with a high-titer (1.24{+/-}0.16 g/L). To the best of our knowledge this is the highest reported rhEPO titer to date. The rhEPO was purified using a series of validated chromatography unit processes including virus inactivation and filtration. The purified EPO was formulated in serum-free buffer, sterile filtered, and analyzed as the biosimilar of reference product Eprex(R). Physicochemical analysis strongly suggested similarities between the developed rhEPO (GBPD002) and the reference. The in vitro and in vivo functional assays confirmed the similar biofunctionality of the GBPD002 and Eprex(R). GBPD002 could provide a less-expensive solution to the needful communities as an effective and safe biosimilar where rhEPO treatment is necessary.

bioengineering↗

bioRxiv2023

Cdc73 protects Notch-induced T-cell leukemia cells from DNA damage and mitochondrial stress

Activated Notch signaling is highly prevalent in T-cell acute lymphoblastic leukemia (T-ALL) but pan-Notch inhibitors were toxic in clinical trials. To find alternative ways to target Notch signals, we investigated Cell division cycle 73 (Cdc73), which is a Notch cofactor and component of transcriptional machinery, a potential target in T-ALL. While we confirmed previous work that CDC73 interacts with NOTCH1, we also found that the interaction in T-ALL was context-dependent and facilitated by the lymphoid transcription factor ETS1. Using mouse models, we showed that Cdc73 is important for Notch-induced T-cell development and T-ALL maintenance. Mechanistically, Cdc73, Ets1, and Notch intersect chromatin at promoters and enhancers to activate oncogenes and genes that are important for DNA repair and oxidative phosphorylation. Consistently, Cdc73 deletion in T-ALL cells induced DNA damage and impaired mitochondrial function. Our data suggests that Cdc73 might promote a gene expression program that was eventually intersected by Notch to mitigate the genotoxic and metabolic stresses of elevated Notch signaling. We also provide mechanistic support for testing inhibitors of DNA repair, oxidative phosphorylation, and transcriptional machinery. Inhibiting pathways like Cdc73 that intersect with Notch at chromatin might constitute a strategy to weaken Notch signals without directly targeting the Notch complex.

cancer biology↗

bioRxiv2023

Recognition determinants of broad and potent HIV-1 neutralization by an affinity matured antibody from a pediatric elite-neutralizer

The structural and characteristic features of HIV-1 broadly neutralizing antibodies (bnAbs) from chronically infected pediatric donors are currently unknown. Herein, we characterized a heavy chain matured HIV-1 bnAb 44m, identified from a pediatric elite-neutralizer. Interestingly, in comparison to its wild-type AIIMS-P01 bnAb, 44m exhibited moderately higher level of somatic hypermutations of 15.2%. The 44m neutralized 79% of HIV-1 heterologous viruses (n=58) tested, with a geometric mean IC50 titer of 0.36 {micro}g/ml. The cryo-EM structure of 44m Fab in complex with fully-cleaved glycosylated native-like BG505.SOSIP.664.T332N gp140 envelope trimer at 4.4[A] resolution revealed that 44m targets the V3-glycan N332-supersite and GDIR motif to neutralize HIV-1 with improved potency and breadth, plausibly attributed by a matured heavy chain as compared to that of wild-type AIIMS-P01. This study further improves our understanding on pediatric HIV-1 bnAbs and structural basis of broad HIV-1 neutralization by 44m may be useful blueprint for vaccine design in future.

immunology↗

bioRxiv2023

A dual MTOR/NAD+ acting gerotherapy

The geroscience hypothesis states that a therapy that prevents the underlying aging process should prevent multiple aging related diseases. The mTOR (mechanistic target of rapamycin)/insulin and NAD+ (nicotinamide adenine dinucleotide) pathways are two of the most validated aging pathways. Yet, its largely unclear how they might talk to each other in aging. In genome-wide CRISPRa screening with a novel class of N-O-Methyl-propanamide-containing compounds we named BIOIO-1001, we identified lipid metabolism centering on SIRT3 as a point of intersection of the mTOR/insulin and NAD+ pathways. In vivo testing indicated that BIOIO-1001 reduced high fat, high sugar diet-induced metabolic derangements, inflammation, and fibrosis, each being characteristic of non-alcoholic steatohepatitis (NASH). An unbiased screen of patient datasets suggested a potential link between the anti-inflammatory and anti-fibrotic effects of BIOIO-1001 in NASH models to those in amyotrophic lateral sclerosis (ALS). Directed experiments subsequently determined that BIOIO-1001 was protective in both sporadic and familial ALS models. Both NASH and ALS have no treatments and suffer from a lack of convenient biomarkers to monitor therapeutic efficacy. A potential strength in considering BIOIO-1001 as a therapy is that the blood biomarker that it modulates, namely plasma triglycerides, can be conveniently used to screen patients for responders. More conceptually, to our knowledge BIOIO-1001 is a first therapy that fits the geroscience hypothesis by acting on multiple core aging pathways and that can alleviate multiple conditions after they have set in. Brief SummaryThese studies characterize a novel gerotherapy, BIOIO-1001, that identifies lipid metabolism as an intersection of the mTOR and NAD+ pathways.

genomics↗

bioRxiv2023

A Cost-effective Purification Process for Erythropoietin Biosimilar through Downstream Process Engineering

Well-characterized and scalable downstream process for purification of biologics is extremely demanding for delivering quality therapeutics to patients at a reasonable price. Erythropoietin (EPO) is a blockbuster biologic with diverse clinical applications but its application is limited to financially well-off societies due to high price. The high price of EPO is associated with the technical difficulties related to the purification challenge to obtain qualified product with a cost-effective defined process. Though there are reports for purification of EPO but there is no report of well-characterized downstream process with critical process parameters (CPPs) that can deliver EPO consistently satisfying the quality target product profile (QTPP), which is a critical regulatory requirement. To advance the field, we applied quality by design (QbD) principle and design of experiment (DoE) protocol to establish an effective process, which is scalable up to 100x batch size satisfying QTPP. We have successfully transformed the process from static mode to dynamic mode and validated. Insignificant variation (p> 0.05) within and between 1x, 10x and 100x batches showed that the process is reproducible and seamlessly scalable. The biochemical analysis along with the biofunctionality data ensures that the products from different-scale batches were indifferent and comparable to a reference product. Our study thereby established a robust and scalable downstream process of EPO biosimilar satisfying QTPP. The technological scheme presented here can speed-up the production of not only EPO but many other life-saving biologics and make them available to mass population at a reduced cost.

bioengineering↗

bioRxiv2023

SUMO protease FUG1, histone reader AL3 and the PRC1 Complex are integral to repeat-expansion induced epigenetic silencing in Arabidopsis thaliana

Epigenetic gene silencing induced by expanded repeats can cause diverse phenotypes ranging from severe growth defects in plants to genetic diseases such as Friedreichs ataxia in humans1. The molecular mechanisms underlying repeat expansion-induced epigenetic silencing remain largely unknown2,3. Using a plant model, we have previously shown that expanded repeats can induce smallRNAs which in turn can lead to epigenetic silencing through the RNA-dependent DNA methylation pathway4,5. Here, using a genetic suppressor screen, we confirm a key role for the RdDM pathway and identify novel components required for epigenetic silencing caused by expanded repeats. We show that FOURTH ULP LIKE GENE CLASS 1 (FUG1) - a SUMO protease, ALFIN-LIKE 3 - a histone reader and LIKE HETEROCHROMATIN 1 (LHP1) - a component of the PRC1 complex are required for repeat expansion-induced epigenetic silencing. Loss of any of these components suppress repeat expansion-associated phenotypes. SUMO protease FUG1 physically interacts with AL3 and perturbing its potential SUMOylation site disrupts its nuclear localisation. AL3 physically interacts with LHP1 of the PRC1 complex and the FUG1-AL3-LHP1 module is essential to confer repeat expansion-associated epigenetic silencing. Our findings highlight the importance post-translational modifiers and histone readers in epigenetic silencing caused by repeat expansions.

genetics↗

bioRxiv2023

Zinc nano-fertilization enhances wheat productivity and biofortification

Zinc (Zn) malnutrition has emerged as one of the major health challenges in developing nations across the globe. Development of Zn management protocols in staple food crops using modern scientific tools to enhance Zn concentration in grains along with augmented crop yields became utmost necessary. In this context a 2-year experiment was carried out to assess the effects of zinc oxide nanoparticles (ZnO-NPs) vis-a-vis bulk zinc sulfate (ZnSO4) on wheat growth, yield and Zn concentration in plant parts. Four levels of application of ZnO-NPs (0, 20, 25 and 30 mg kg-1) were compared with ZnSO4 (equal to Zinc concentration in ZnO-NPs). Results revealed that seed vigor was significantly (p <0.05) higher under 25 and 30 mg kg-1 soil ZnO-NPs treatments over ZnSO4. Among the crop yield parameters such as tillers (plant-1), grain weight (plant-1), biomass (plant-1) and grain yield were significantly (p <0.05) higher under ZnO-NPs 25 mg kg-1 treated soil as compared to any other treatment. Zinc concentration in grains increased with dose of ZnO-NPs and it was significantly more than ZnSO4 treated soil at each treatment level. ZnO-NPs and ZnSO4 treatments did not affect photosynthetic rate and chlorophyll (SPAD) content significantly. In conclusion, 25 mg kg-1 ZnO-NPs application could be recommended in wheat cultivation to improve growth, yield and grain Zn biofortification.

plant biology↗

bioRxiv2022

Folic acid-loaded chitosan nanoparticles: Cytotoxicity, acute and sub-acute oral toxicity and bioavailability in Wistar rats

The study aims to develop folic acid-loaded chitosan nanoparticles (FA-Chi-NPs) as the vitamin is sensitive to heat and light and to investigate the safety of FA-Chi-NPs in vitro and in vivo. The prepared formulation showed an average diameter of 191.7 {+/-} 2 nm with a zeta potential of + 52 {+/-} 4 mV and PDI of 0.195 {+/-} 0.03. The encapsulation efficiency was found to be 80%. In vitro cytotoxicity assays revealed that FA-Chi-NPs had no cytotoxic effect on Caco-2 cells. Acute-toxicity and subacute-toxicity of FA-Chi-NPs (0.4, 2, and 4 mg/kg body weight) revealed no mortality, and no gross morphological abnormalities were noticed. There were no dose-dependent toxic effects of free folic acid (FA) and FA-Chi-NPs in haematological, histological, plasma biochemical indices, oxidative stress enzymes, or other parameters when compared to the control group(s). The plasma and tissue levels of FA from FA-Chi-NPs were significantly higher. Results demonstrated enhanced bioavailability of FA from FA-Chi-NPs with no toxicity. Practical applicationsIn the current study, nanoencapsulation is used as a potential approach to enhance folic acid bioavailability. The results showed that encapsulating folic acid in chitosan improved bioavailability with no apparent adverse effects, and thus chitosan could be a promising polymer for safe folic acid delivery.

pharmacology and toxicology↗

bioRxiv2022

ATR inhibition augments the efficacy of lurbinectedin in small cell lung cancer

Abstract/SummarySmall cell lung cancer (SCLC) is the most lethal type of lung cancer. Specifically, MYC-driven non-neuroendocrine SCLC are particularly resistant to standard therapies. Lurbinectedin was recently approved for the treatment of relapsed SCLC, but combinatorial approaches are needed to increase the depth and duration of responses to lurbinectedin. Using high-throughput screens, we found inhibitors of ataxia telangiectasia-mutated and rad3-related (ATR) as the most effective agents for augmenting lurbinectedin efficacy. First-in-class ATR inhibitor berzosertib synergized with lurbinectedin in multiple SCLC cell lines, organoid and in-vivo models. Mechanistically, ATR inhibition abrogated S-phase arrest induced by lurbinectedin and forced cell-cycle progression causing mitotic catastrophe and cell death. High CDKN1A/p21 expression was associated with decreased synergy due to G1 arrest, while increased levels of ERCC5/XPG were predictive of increased combination efficacy. Importantly, MYC-driven non-neuroendocrine tumors which were resistant to first-line therapies displayed decreased CDKN1A/p21 expression and increased ERCC5/XPG indicating they were primed for response to lurbinectedin-berzosertib combination. The combination is being assessed in a clinical trial NCT04802174. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=198 SRC="FIGDIR/small/520783v1_ufig1.gif" ALT="Figure 1"> View larger version (63K): org.highwire.dtl.DTLVardef@19acf72org.highwire.dtl.DTLVardef@a9703forg.highwire.dtl.DTLVardef@86592org.highwire.dtl.DTLVardef@1448372_HPS_FORMAT_FIGEXP M_FIG C_FIG

cancer biology↗