NRF2-GPX4/SOD2 axis imparts resistance to EGFR-tyrosine kinase inhibitors in non-small-cell lung cancer cells

Epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) have achieved satisfactory clinical effects in the therapy of non-small cell lung cancer (NSCLC), but acquired resistance limits their clinical application. NRF2 has been shown to enhance the resistance to apoptosis induced by radiotherapy and some chemotherapy. In this study, we investigated the role of NRF2 in resistance to EGFR-TKIs. We showed that NRF2 protein levels were markedly increased in a panel of EGFR-TKI-resistant NSCLC cell lines due to slow degradation of NRF2 protein. NRF2 knockdown overcame the resistance to EGFR-TKIs in HCC827ER and HCC827GR cells. Furthermore, we demonstrated that NRF2 imparted EGFR-TKIs resistance in HCC827 cells via upregulation of GPX4 and SOD2, and suppression of GPX4 and SOD2 reversed resistance to EGFR-TKIs. Thus, we conclude that targeting NRF2-GPX4/SOD2 pathway is a potential strategy for overcoming resistance to EGFR-TKIs.

Nucleobase-functionalized acrylic ABA triblock copolymers and supramolecular blends

The supramolecular blend of complementary nucleobase-functionalized ABA triblock copolymers self-assemble into a microphase-separated morphology with enhanced mechanical performance and thermal responsiveness.

Self-assembly of polycyclic supramolecules using linear metal-organic ligands

Coordination-driven self-assembly as a bottom-up approach has witnessed a rapid growth in building giant structures in the past few decades. Challenges still remain, however, within the construction of giant architectures in terms of high efficiency and complexity from simple building blocks. Inspired by the features of DNA and protein, which both have specific sequences, we herein design a series of linear building blocks with specific sequences through the coordination between terpyridine ligands and Ru(II). Different generations of polycyclic supramolecules (C1 to C5) with increasing complexity are obtained through the self-assembly with Cd(II), Fe(II) or Zn(II). The assembled structures are characterized via multi-dimensional mass spectrometry analysis as well as multi-dimensional and multinuclear NMR (1H, COSY, NOESY) analysis. Moreover, the largest two cycles C4 and C5 hierarchically assemble into ordered nanoscale structures on a graphite based on their precisely-controlled shapes and sizes with high shape-persistence.

Self-Assembly of Supramolecular Fractals from Generation 1 to 5

In the seeking of molecular expression of fractal geometry, chemists have endeavored in the construction of molecules and supramolecules during the past few years, while only a few examples were reported, especially for the discrete architectures. We herein designed and constructed five generations of supramolecular fractals (G1-G5) based on the coordination-driven self-assembly of terpyridine ligands. All the ligands were synthesized from triphenylamine motif, which played a central role in geometry control. Different approaches based on direct Sonogashira coupling and/or ⟨tpy-Ru(II)-tpy⟩ connectivity were employed to prepare complex Ru(II)-organic building blocks. Fractals G1-G5 were obtained in high yields by precise coordination of organic or Ru(II)-organic building blocks with Zn(II) ions. Characterization of those architectures were accomplished by 1D and 2D NMR spectroscopy, electrospray ionization mass spectrometry (ESI-MS), traveling-wave ion mobility mass spectrometry (TWIM-MS), and transmission electron microscopy (TEM). Furthermore, the two largest fractals also hierarchically self-assemble into ordered supramolecular nanostructures either at solid/liquid interface or in solution on the basis of their well-defined scaffolds.

Nucleobase-functionalized ABC triblock copolymers: self-assembly of supramolecular architectures

RAFT polymerization afforded acrylic ABC triblock copolymers with self-complementary nucleobase-functionalized external blocks and a low-Tg soft central block. ABC triblock copolymers self-assembled into well-defined lamellar microphase-separated morphologies for potential applications as thermoplastic elastomers. Complementary hydrogen bonding within the hard phase facilitated self-assembly and enhanced mechanical performance.

Quantitative analysis of sacral parasympathetic nucleus innervating the rectum in rats with anorectal malformation

BACKGROUND/PURPOSE

The purpose of this experiment was to identify the neurons in the lumbosacral spinal cord involved in colon-rectal function and to compare normal and anorectal malformation of fetal rats.

METHODS

The authors quantified the sacral parasympathetic nucleus (SPN) innervation of the rectum by Fluorogold (FG) (Fluorochrome, Englewood, CO) retrograde tracing experiment in fetal rats with normal and anorectal malformation. Anorectal malformation was induced in rat fetuses by ethylenethiourea (ETU). The number of FG-labeled SPNs was scored and compared between male fetuses with or without malformation in the ETU-fed group and control groups.

RESULTS

The number of FG-labeled SPNs in the fetuses without a defect, with ETU injected but without any defects of the anorectum or neural tube, with low-type deformity, and with high-type deformity were (mean +/- SEM) 47.3 +/- 2.9, 45.6 +/- 3.2, 24.2 +/- 3.8, and 8.5 +/- 2.5, respectively. Fluorogold-labeled SPNs in the fetuses with high-type deformity were significantly fewer than those in fetuses without defects (P<.05) and in controls (P < .05).

CONCLUSIONS

These findings suggest that defective SPN innervation to the rectum is a primary anomaly that coexists with the alimentary tract anomaly in anorectal malformation during fetal development. The intrinsic neural deficiency is an important factor likely to contribute to poor postoperative anorectal function despite surgical correction of the malformation.

Styrenic DABCO salt-containing monomers for the synthesis of novel charged polymers

Styrenic DABCO salt monomers enabled synthesis of microphase-separated ionomers with doubly-charged pendant groups.

Ureido cytosine and cytosine-containing acrylic copolymers

Ureido-cytosine pendant groups contributed to random acrylic copolymers with enhanced thermomechanical performance, well-defined morphologies, and reduced water uptake.

Proteomic profiling and genome-wide mapping of O-GlcNAc chromatin-associated proteins reveal an O-GlcNAc-regulated genotoxic stress response

O-GlcNAc modification plays critical roles in regulating the stress response program and cellular homeostasis. However, systematic and multi-omics studies on the O-GlcNAc regulated mechanism have been limited. Here, comprehensive data are obtained by a chemical reporter-based method to survey O-GlcNAc function in human breast cancer cells stimulated with the genotoxic agent adriamycin. We identify 875 genotoxic stress-induced O-GlcNAc chromatin-associated proteins (OCPs), including 88 O-GlcNAc chromatin-associated transcription factors and cofactors (OCTFs), subsequently map their genomic loci, and construct a comprehensive transcriptional reprogramming network. Notably, genotoxicity-induced O-GlcNAc enhances the genome-wide interactions of OCPs with chromatin. The dynamic binding switch of hundreds of OCPs from enhancers to promoters is identified as a crucial feature in the specific transcriptional activation of genes involved in the adaptation of cancer cells to genotoxic stress. The OCTF nuclear respiratory factor 1 (NRF1) is found to be a key response regulator in O-GlcNAc-modulated cellular homeostasis. These results provide a valuable clue suggesting that OCPs act as stress sensors by regulating the expression of various genes to protect cancer cells from genotoxic stress.

Protein O-GlcNAcylation is involved in regulating gene expression and maintaining cellular homeostasis. Here, the authors develop a chemical reporter-based strategy for the proteomic profiling and genome-wide mapping of genotoxic stress-induced O-GlcNAcylated chromatin-associated proteins.

High-Resolution Metabolomic Assessment of Pesticide Exposure in Central Valley, California

Pesticides are widely used in the agricultural Central Valley region of California. Historically, this has included organophosphates (OPs), organochlorines (OCs), and pyrethroids (PYRs). This study aimed to identify perturbations of the serum metabolome in response to each class of pesticide and mutual associations between groups of metabolites and multiple pesticides. We conducted high-resolution metabolomic profiling of serum samples from 176 older adults living in the California Central Valley using liquid chromatography with high-resolution mass spectrometry. We estimated chronic pesticide exposure (from 1974 to year of blood draw) to OPs, OCs, and PYRs from ambient sources at homes and workplaces with a geographic information system (GIS)-based model. Based on partial least-squares regression and pathway enrichment analysis, we identified metabolites and metabolic pathways associated with one or multiple pesticide classes, including mitochondrial energy metabolism, fatty acid and lipid metabolism, and amino acid metabolism. Utilizing an integrative network approach, we found that the fatty acid β-oxidation pathway is a common pathway shared across all three pesticide classes. The disruptions of the serum metabolome suggested that chronic pesticide exposure might result in oxidative stress, inflammatory reactions, and mitochondrial dysfunction, all of which have been previously implicated in a wide variety of diseases. Overall, our findings provided a comprehensive view of the molecular mechanisms of chronic pesticide toxicity, and, for the first time, our approach informs exposome research by moving from macrolevel population exposures to microlevel biologic responses.

MicroRNA-215 functions as a tumor suppressor and directly targets ZEB2 in human pancreatic cancer

It has been shown that microRNA-215 (miR-215) is dysregulated in several human malignancies, and this correlates with tumor progression. However, its expression and function in pancreatic cancer is still unclear. The aim of this study was to explore the effects of miR-215 on pancreatic cancer formation and progression. Using quantitative RT-PCR, we detected miR-215 expression in pancreatic cancer cell lines and primary tumor tissues. The association of miR-215 expression with clinicopathological factors and prognosis was also analyzed. We then observed the effects of miR-215 on the biological behavior of pancreatic cancer cells. Lastly, the potential regulatory function of miR-215 on ZEB2 expression was investigated. miR-215 expression levels were significantly downregulated in pancreatic cancer samples and cell lines. Decreased miR-215 expression was significantly associated with large tumor size, advanced TNM stage, lymph node metastasis, vessel invasion, and lower overall survival. Multivariate regression analysis corroborated that downregulation of miR-215 was an independent unfavorable prognostic factor. Overexpression of miR-215 inhibited pancreatic cancer cell proliferation, invasion, and migration; promoted cell apoptosis in vitro; and suppressed tumorigenicity in vivo. Further, ZEB2 was confirmed as a direct target of miR-215 by using a luciferase reporter assay. These findings indicate that miR-215 may act as a tumor suppressor in pancreatic cancer cells, and could serve as a novel therapeutic target for miR-based therapy.

Influence of nucleobase stoichiometry on the self-assembly of ABC triblock copolymers

ABC triblock copolymers bearing adenine- and thymine-functionalized external blocks self-assembled into long-range, ordered lamellar microphase-separated morphologies on non-patterned substrates. Intermolecular hydrogen bonding formed thymine-adenine triplets and promoted self-assembly into well-defined lamellae consisting of poly(n-butyl acrylate) soft domains and complementary nucleobase hard domains, while thymine-adenine duplets contributed to superior mechanical properties.

5-IP7 is a GPCR messenger mediating neural control of synaptotagmin-dependent insulin exocytosis and glucose homeostasis

5-diphosphoinositol pentakisphosphate (5-IP₇) is a signalling metabolite linked to various cellular processes. How extracellular stimuli elicit 5-IP₇ signalling remains unclear. Here we show that 5-IP₇ in β cells mediates parasympathetic stimulation of synaptotagmin-7 (Syt7)-dependent insulin release. Mechanistically, vagal stimulation and activation of muscarinic acetylcholine receptors triggers G_αq-PLC-PKC-PKD-dependent signalling and activates IP6K1, the 5-IP₇ synthase. Whereas both 5-IP₇ and its precursor IP₆ compete with PIP₂ for binding to Syt7, Ca²⁺ selectively binds 5-IP₇ with high affinity, freeing Syt7 to enable fusion of insulin-containing vesicles with the cell membrane. β-cell-specific IP6K1 deletion diminishes insulin secretion and glucose clearance elicited by muscarinic stimulation, whereas mice carrying a phosphorylation-mimicking, hyperactive IP6K1 mutant display augmented insulin release, congenital hyperinsulinaemia and obesity. These phenotypes are absent in mice lacking Syt7. Our study proposes a new conceptual framework for inositol pyrophosphate physiology in which 5-IP₇ acts as a GPCR second messenger at the interface between peripheral nervous system and metabolic organs, transmitting G_q-coupled GPCR stimulation to unclamp Syt7-dependent, and perhaps other, exocytotic events.

LIN28B gene polymorphisms modify hepatoblastoma susceptibility in Chinese children

Hepatoblastoma is one of the malignant liver tumors in children. However, genetic mechanisms underpinning the initiation of hepatoblastoma remain largely unclear. The previous study showed that lin-28 homolog B (LIN28B) might play a role in the development of hepatoblastoma. To detect the association between LIN28B gene polymorphisms and hepatoblastoma risk in Chinese children, we conducted a five-center case-control study of 275 hepatoblastoma patients and 1018 cancer-free controls. Four potentially functional polymorphisms were genotyped using the Taqman method. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to evaluate the strength of the associations. We found that the rs314276 C>A polymorphism (AA vs. CC: adjusted OR=2.05, 95% CI=1.36-3.10, P=0.0006; AA vs. CA/CC: adjusted OR=2.11, 95% CI=1.43-3.12, P=0.0002) and rs9404590 T>G (GG vs. TT: adjusted OR=1.89, 95% CI=1.20-3.00, P=0.007; GG vs. TT/TG: adjusted OR=1.87, 95% CI=1.20-2.92, P=0.006) were associated with increased hepatoblastoma risk. Combination analysis of risk genotypes showed that patients with four risk genotypes had a higher chance of developing hepatoblastoma than carriers of 1 to 3 risk genotypes. Stratification analysis showed the significant association between the rs314276 AA genotype and hepatoblastoma risk in both age and sex groups, as well as clinical stages III+IV cases. The rs9404590 GG genotype was associated with hepatoblastoma risk in participants' ≥17 months, in females, and for those with clinical stages III+IV disease. Furthermore, four risk genotypes confer higher hepatoblastoma susceptibility in both age and sex groups, as well as groups with clinical stages III+IV disease. Genotype-based gene expression analysis confirmed that the rs9404590 T>G polymorphism was significantly associated with altered LIN28B gene expression. We further validated our findings using false-positive probability analysis. This finding suggested that LIN28B gene polymorphisms may be associated with an increased predisposition to hepatoblastoma.

O-GlcNAc modification regulates MTA1 transcriptional activity during breast cancer cell genotoxic adaptation

BACKGROUND

Chromatin modifier metastasis-associated protein 1 (MTA1), closely associated with tumor angiogenesis in breast cancer, plays an important role in gene expression and cancer cell behavior. Recently, an association between O-GlcNAc transferase (OGT) and MTA1 was identified by mass spectroscopy. However, the potential relationship between MTA1 and O-GlcNAc modification has not yet explored.

METHODS

In the current study, the role of MTA1 and its O-GlcNAc modification in breast cancer cell genotoxic adaptation was investigated through quantitative proteomics, chromatin immunoprecipitation followed by sequencing (ChIP-seq), transcriptome analysis, and loss- and gain-of-function experiments.

RESULTS

We demonstrate that the O-GlcNAc modification promotes MTA1 to interaction with chromatin and thus changes the expression of target genes, contributing to breast cancer cell genotoxic adaptation. MTA1 is modified with O-GlcNAc residues at serine (S) residues S237/S241/S246 in adriamycin-adaptive breast cancer cells, and this modification improves the genome-wide interactions of MTA1 with gene promotor regions by enhancing its association with nucleosome remodeling and histone deacetylation (NuRD) complex. Further, O-GlcNAc modification modulates MTA1 chromatin binding, influencing the specific transcriptional regulation of genes involved in the adaptation of breast cancer cells to genotoxic stress.

CONCLUSIONS

Our findings reveal a previously unrecognized role for O-GlcNAc-modified MTA1 in transcriptional regulation and suggest that the O-GlcNAc modification is a key to the molecular regulation of chemoresistance in breast cancers.

ppGalNAc-T4-catalyzed O-Glycosylation of TGF-β type Ⅱ receptor regulates breast cancer cells metastasis potential

GalNAc-type O-glycosylation, initially catalyzed by polypeptide N-acetylgalactosaminyltransferases (ppGalNAc-Ts), is one of the most abundant and complex posttranslational modifications of proteins. Emerging evidence has proven that aberrant ppGalNAc-Ts are involved in malignant tumor transformation. However, the exact molecular functions of ppGalNAc-Ts are still unclear. Here, the role of one isoform, ppGalNAc-T4, in breast cancer cell lines was investigated. The expression of ppGalNAc-T4 was found to be negatively associated with migration of breast cancer cells. Loss-of-function studies revealed that ppGalNAc-T4 attenuated the migration and invasion of breast cancer cells by inhibiting the epithelial-mesenchymal transition (EMT) process. Correspondingly, transforming growth factor beta (TGF-β) signaling, which is the upstream pathway of EMT, was impaired by ppGalNAc-T4 expression. ppGalNAc-T4 knockout decreased O-GalNAc modification of TGF-β type Ⅰ and Ⅱ receptor (TβR Ⅰ and Ⅱ) and led to the elevation of TGF-β receptor dimerization and activity. Importantly, a peptide from TβR Ⅱ was identified as a naked peptide substrate of ppGalNAc-T4 with a higher affinity than ppGalNAc-T2. Further, Ser31, corresponding to the extracellular domain of TβR Ⅱ, was identified as the O-GalNAcylation site upon in vitro glycosylation by ppGalNAc-T4. The O-GalNAc-deficient S31 A mutation enhanced TGF-β signaling activity and EMT in breast cancer cells. Together, these results identified a novel mechanism of ppGalNAc-T4-catalyzed TGF-β receptors O-GalNAcylation that suppresses breast cancer cell migration and invasion via the EMT process. Targeting ppGalNAc-T4 may be a potential therapeutic strategy for breast cancer treatment.

Proximity to residential and workplace pesticides application and the risk of progression of Parkinson's diseases in Central California

BACKGROUND

Pesticide exposure has consistently been associated with Parkinson's disease (PD) onset. Yet, fewer epidemiologic studies have examined whether pesticides influence PD motor and non-motor symptom progression.

OBJECTIVES

Using a geographic information system tool that integrates agricultural pesticide use reports and land use records to derive ambient exposures at residences and workplaces, we assessed associations between specific pesticides previously related to PD onset with PD symptom progression in two PD patient cohorts living in agricultural regions of California.

METHODS

We calculated the pounds of pesticide applied agriculturally near each participant's residential or occupational addresses from 1974 to the year of PD diagnosis, using a geographic information system tool that links the California Pesticide Use Reports database to land use data. We examined 53 pesticides selected a priori as they have previously been associated with PD onset. We longitudinally followed two PD patient cohorts (PEG1 N = 242, PEG2 N = 259) for an average of 5.0 years (SD ± 3.5) and 2.7 years (SD ± 1.6) respectively and assessed PD symptoms using the movement disorder specialist-administered Unified Parkinson's disease Rating Scale part III (UPDRS), Mini-Mental State Examination (MMSE), and Geriatric Depression Scale (GDS). Weighted time-to-event regression models were implemented to estimate effects.

RESULTS

Ten agricultural pesticides, including copper sulfate (pentahydrate), 2-methyl-4-chlorophenoxyacetic acid (MCPA) dimethylamine salt, tribufos, sodium cacodylate, methamidophos, ethephon, propargite, bromoxynil octanoate, monosodium methanearsonate (MSMA), and dicamba, were associated with faster symptom progression. Among these pesticides, residential or workplace proximity to higher amounts of copper sulfate (pentahydrate) and MCPA (dimethylamine salt) was associated with all three progression endpoints (copper sulfate: HRs = 1.22-1.36, 95 % CIs = 1.03-1.73; MCPA: HRs = 1.27-1.35, 95 % CIs = 1.02-1.70).

CONCLUSIONS

Our findings suggest that pesticide exposure may not only be relevant for PD onset but also PD progression phenotypes. We have implicated ten specific pesticide active ingredients in faster PD motor and non-motor decline.

Immunosuppressive effects of dihydroetorphine, a potent narcotic analgesic, in dihydroetorphine-dependent mice

The immunomodulatory effects of dihydroetorphine were systematically investigated in subchronically treated mice. In a dose-dependent fashion, dihydroetorphine (total doses at 444.5, 889 and 1778 microg/kg) lowered the increase of body weight, decreased the weight of the spleen and thymus, weakened the delayed-type hypersensitivity, reduced the generation of antibody-forming cells, inhibited splenic lymphocyte proliferation induced by concanavalin A and lipopolysaccharide, suppressed the production of interleukin-2 in the supernatant of splenocytes induced by concanavalin A, and depleted the ratio of CD4+ and CD8+ subpopulations. Moreover, the physical dependence on dihydroetorphine was also evaluated to confirm that the immunosuppression was concomitant with the addiction to the drug. These results demonstrate that subchronic treatment with dihydroetorphine dose dependently suppresses both humoral and cell-mediated immune function, and that the immunosuppressive effects of dihydroetorphine are much more potent than those of morphine.

Caffeic acid phenethyl ester (CAPE) revisited: Covalent modulation of XPO1/CRM1 activities and implication for its mechanism of action

Caffeic acid phenethyl ester (CAPE) is the bioactive constituent of propolis from honeybee hives and is well known for its anti-inflammatory, anticarcinogenic, antioxidant, and immunomodulatory properties. Herein, we revisited the cellular mechanism underlying the diverse biological effects of CAPE. We demonstrated that XPO1/CRM1, a major nuclear export receptor, is a cellular target of CAPE. Through nuclear export functional assay, we observed a clear shift of XPO1 cargo proteins from a cytoplasmic localization to nucleus when treated with CAPE. In particular, we showed that CAPE could specifically target the non-catalytic and conserved Cys528 of XPO1 through the means of mass spectrometric analysis. In addition, we demonstrated that the mutation of Cys528 residue in XPO1 could rescue the nuclear export defects caused by CAPE. Furthermore, we performed position-restraint molecular dynamics simulation to show that the Michael acceptor moiety of CAPE is the warhead to enable covalent binding with Cys528 residue of XPO1. The covalent modulation of nuclear export by CAPE may explain its diverse biological effects. Our findings may have general implications for further investigation of CAPE and its structural analogs.