Development of Sequence-Controlled, Degradable, and Cytocompatible Oligomers with Explicit Fragmentation Pathways.

Sequence-defined and degradable polymers can mimic biopolymers, such as peptides and DNA, to undertake life-supporting functions in a chemical way. The design and development of well-structured oligomers/polymers is the most concern for the public, even to further uncover their degradation process illustrating the degraded products and their properties. However, seldom investigation has been reported on the aforementioned aspects. In this work, the alternating photo-reversible addition-fragmentation chain-transfer (photo-RAFT) single unit monomer insertion (SUMI) of different N-substituted maleimides and thermal radical ring-opening SUMI of a cyclic ketene acetal monomer (i.e., 5,6-benzo-2-methylene-1,3-dioxepane (BMDO)) is adopted, to produce two degradable pentamers owing to the conversion of the exo-methylene group of BMDO into ester bonds along the main chains of the prepared products. Moreover, the possible degraded approach of pentamers is studied by combining high-resolution mass spectrometry (HRMS) and liquid chromatography-mass spectrometry (LC-MS) for the first time. This work also sheds light on the precise structures and cytotoxicity of SUMI products and their degraded compounds, proposing a detailed and credible outlook for biomedical applications.

Iodine-Modified Ag NPs for Highly Sensitive SERS Detection of Deltamethrin Residues on Surfaces.

It is essential to estimate the indoor pesticides/insecticides exposure risk since reports show that 80% of human exposure to pesticides occurs indoors. As one of the three major contamination sources, surface collected pesticides contributed significantly to this risk. Here, a highly sensitive liquid freestanding membrane (FSM) SERS method based on iodide modified silver nanoparticles (Ag NPs) was developed for quantitative detection of insecticide deltamethrin (DM) residues in solution phase samples and on surfaces with good accuracy and high sensitivity. The DM SERS spectrum from 500 to 2500 cm-1 resembled the normal Raman counterpart of solid DM. Similar bands at 563, 1000, 1165, 1207, 1735, and 2253 cm-1 were observed as in the literature. For the quantitative analysis, the strongest peak at 1000 cm-1 that was assigned to the stretching mode of the benzene ring and the deformation mode of C-C was selected. The peak intensity at 1000 cm-1 and the concentration of DM showed excellent linearity from 39 to 5000 ppb with a regression equation I = 649.428 + 1.327 C (correlation coefficient R2 = 0.991). The limit of detection (LOD) of the DM was found to be as low as 11 ppb. Statistical comparison between the proposed and the HPLC methods for the analysis of insecticide deltamethrin (DM) residues in solution phase samples showed no significant difference. DM residue analysis on the surface was mimicked by dropping DM pesticide on the glass surface. It is found that DM exhibited high residue levels up to one week after exposure. This proposed SERS method could find application in the household pesticide residues analysis.

CCT5 induces epithelial-mesenchymal transition to promote gastric cancer lymph node metastasis by activating the Wnt/ß-catenin signalling pathway.

BACKGROUND: Lymph node (LN) metastasis confers gastric cancer (GC) progression, poor survival and cancer-related death. Aberrant activation of Wnt/ß-catenin promotes epithelial-mesenchymal transition (EMT) and LN metastasis, whereas the constitutive activation mutation of Wnt/ß-catenin is rare in GC, suggesting that the underlying mechanisms enhancing Wnt/ß-catenin activation need to be further investigated and understood. METHODS: Bioinformatics analyses and immunohistochemistry (IHC) were used to identify and detect LN metastasis-related genes in GC. Cellular functional assays and footpad inoculation mouse model illustrate the biological function of CCT5. Co-immunoprecipitation assays, western blot and qPCR elucidate the interaction between CCT5 and E-cadherin, and the regulation on ß-catenin activity. RESULTS: CCT5 is upregulated in LN metastatic GCs and correlates with poor prognosis. In vitro assays prove that CCT5 markedly promotes GC cell proliferation, anti-anoikis, invasion and lymphatic tube formation. Moreover, CCT5 enhances xenograft GC growth and popliteal lymph node metastasis in vivo. Furthermore, CCT5 binds the cytoplasmic domain of E-cadherin and abrogates the interaction between E-cadherin and ß-catenin, thereby releasing ß-catenin to the nucleus and enhancing Wnt/ß-catenin signalling activity and EMT. CONCLUSION: CCT5 promotes GC progression and LN metastasis by enhancing wnt/ß-catenin activation, suggesting a great potential of CCT5 as a biomarker for GC diagnosis and therapy.

Photoinduced free radical-releasing systems and their anticancer properties.

Cancer has been a serious threat and impact on the health and life of human. Phototherapy is considered as a promising therapeutic method to replace the traditional treatment in clinic owing to its noninvasive nature and high efficiency. Photoinitiators have long been used in the field of photopolymerization; however, few studies have been carried out on their potential as anticancer agents under light irradiation. In this study, the effect of a photoinitiator, diphenyl (2, 4, 6-trimethylbenzoyl) phosphine oxide (TPO), on breast cancer is investigated and the related mechanism is elucidated. It is found that TPO has low dark toxicity and significant phototoxicity. TPO can inhibit cell growth and development and promote cell apoptosis through a mitochondrial pathway under light irradiation. Further studies show that cell apoptosis is induced by free radicals produced from the photolysis of TPO to activate JNK phosphorylation. Overall, we identify the antitumor effects of TPO in vitro for the first time, and provides a proof of concept for its application as a novel photolatent therapeutic drug.

Recent advances in light-regulated non-radical polymerisations.

Light is one of the non-invasive stimuli which can be used in the spatiotemporal control of chemical reactions. Over the past decade, light has found wide applications in polymer science such as polymer synthesis, release of small molecules from polymers and polymeric photosensors etc. Reviews on light-regulated polymerisations have predominately focused on the free radical process. However, the marriage of light to non-radical polymerisations, e.g. ionic, ring-opening, metathesis, step-growth and supramolecular photopolymerisations, has also spurred tremendous research interest to develop materials. These kinds of non-radical photopolymerisations, compared to the free radical approach, are advantageous in overcoming oxygen inhibition, accessing novel polymer structures and fabricating degradable and dynamic polymers. The relevant light-regulation techniques involved in these polymerisations are usually based on photolinking reactions and photoactivation of latent species. These species produce initiators, catalysts or monomers upon light irradiation to manipulate polymer formation. These techniques have been successfully implemented to adapt conditional polymerisations under light, discover novel polymerisation methods and precisely control polymer structures. This review aims to highlight the recent progress in light-regulated non-radical polymerisations in the development of polymerisation techniques as well as the applications in materials science, emphasising the remaining challenges and promising perspective in the relevant fields.

Deltex-1 is indispensible for the IL-6 and TGF-ß treatment-triggered differentiation of Th17 cells.

CSL(CBF1, Su(H) and LAG-1)-dependent Hes-1 signaling plays an important part in regulating Th17 cell differentiation. However, little is known about influence of CSL-independent Deltex-1 signaling on this subset. The current focus is on roles of the Deltex-1 signaling in the Th17 cell differentiation. IL-17-producing CD4+ T cell subpopulation could be induced in vitro by treatment of both IL-6 and TGF-ß. This could be reversed by knockdown of the deltex-1 gene, following the attenuation of retinoic acid-related orphan receptor γt (RORγt) and its DNA-binding activity in nuclei. Subsequently, Th17-associated cytokines generated by the treated cells were also diminished by the inhibition of Deltex-1 signaling, but the production of IL-10 was enhanced. Contrary to the alteration of RORγt, both zinc-finger transcription factor-3 (GATA3) and transcription factor Forkhead box P3 (Foxp3) were augmented at their mRNA and protein levels as well as DNA-binding activities with the emerging phenotypes of the corresponding cellular subpopulation and T-bet (encoded by TBX21) was not changed. These results reveal for the first time that Deltex-1 is indispensible for the IL-6 and TGF-ß treatment-triggered differentiation of Th17 cells, indicating that CSL-independent Deltex-1 signaling favors naïve CD4+ T cells to deviate into Th17 cells via the enhancement of RORγt/IL-17A.

Peripheral RAFT Polymerization on a Covalent Organic Polymer with Enhanced Aqueous Compatibility for Controlled Generation of Singlet Oxygen.

A covalent organic polymer (COP) is prepared by crosslinking the photosensitizer 4,4',4'',4'''-(porphyrin-5,10,15,20-tetrayl)tetraaniline (TAPP) with 4,4'-(anthracene-9,10-diyl)dibenzoic acid (ADDA) via 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide/4-dimethylaminopyridine coupling. The COP is further modified with a hydrophilic polymer, poly(poly(ethylene glycol) methyl ether methacrylate) by grafting-from reversible-addition-fragmentation chain transfer (RAFT) polymerization to enhance its solubility in various solvents. The modified COP can bind singlet oxygen through the formation of endoperoxide by ADDA upon the exposure to red light irradiation. Singlet oxygen can be then released via the photodynamic mechanism or the cycloreversion by endoperoxide when heated at 110 °C. These results open new possibilities for simultaneous generation of singlet oxygen by the photodynamic route and singlet oxygen carriers, demonstrating promise for treating hypoxic tumors.

Antizyme inhibitor 1: a potential carcinogenic molecule.

Polyamines are multivalent and organic cations essential for cellular growth, proliferation, differentiation, and apoptosis. Increased levels of polyamines are closely associated with numerous forms of cancer. An autoregulatory circuit composed of ornithine decarboxylase (ODC), antizyme (AZ) and antizyme inhibitor (AZI) govern the intracellular level of polyamines. Antizyme binds with ODC to inhibit ODC activity and to promote the ubiquitin-independent degradation of ODC. Antizyme inhibitor binds to AZ with a higher affinity than ODC. Consequently, ODC is released from the ODC-AZ complex to rescue its activity. Antizyme inhibitor increases the ODC activity to accelerate the formation of intracellular polyamines, triggering gastric and breast carcinogenesis as well as hepatocellular carcinoma and esophageal squamous cell carcinoma development. Antizyme inhibitor 1 (AZIN1), a primary member of the AZI family, has aroused more attention because of its contribution to cancer. Even though its conformation is changed by adenosine-to-inosine (A→I) RNA editing, it plays an important role in tumorigenesis through regulating intracellular polyamines. Encouragingly, AZIN1 has been revealed to have an additional function outside the polyamine pathway so as to bypass the deficiency of targeting the polyamine biosynthetic pathway, promising to become a critical target for cancer therapy. Here, we review the latest research advances into AZIN1 and its potential contribution to carcinogenesis.

LncRNA HANR Promotes Tumorigenesis and Increase of Chemoresistance in Hepatocellular Carcinoma.

BACKGROUND/AIMS: Hepatocellular carcinoma (HCC) is the fifth most common cancer in the world and the third leading cause of cancer-related death. Critical roles for long non-coding RNAs (lncRNAs) have recently been demonstrated for a variety of cancers, including hepatocellular carcinoma. However, the effect and mechanism of lncRNAs in HCC tumorigenesis and chemoresistance have not been extensively characterized. METHODS: In the current study, we have identified a HCC-expressed lncRNA termed as HANR (HCC associated long non-coding RNA). We identified HANR by microarray analysis and validated its up-regulated expression by quantitative PCR. RNA pull-down and pathway analyses were conducted to evaluate physical and functional interactions with HANR. In vivo experiments were performed to assess tumorigenesis and increase of chemoresistance. In addition, the HANR expression in HCC specimens was detected by FISH. Xenograft and orthotopic mice model was constructed to observe the effect of HANR on tumorigenesis and chemoresistance in vivo. RESULTS: HANR was demonstrated to be up-regulated in HCC patients and HCC cell lines. Increased HANR expression in HCC predicted short survival of patients. Knock-down of HANR markedly retarded cell proliferation, suppressed HCC xenograft/orthotopic tumor growth, induced apoptosis and enhanced chemosensitivity to doxorubicin, while over-expression of HANR showed the opposite effects. It was found that HANR bind to GSKIP for regulating the phosphorylation of GSK3ß in HCC. CONCLUSION: Our results demonstrate that HANR contributes to the development of HCC and is a promising therapeutic target for chemosensitization of HCC cells to doxorubicin, which may represent a promising therapeutic target in the future.

Role of CSL-dependent and independent Notch signaling pathways in cell apoptosis.

Apoptosis is a normally biological phenomenon in various organisms, involving complexly molecular mechanisms with a series of signaling processes. Notch signaling is found evolutionarily conserved in many species, playing a critical role in embryonic development, normal tissue homeostasis, angiogenesis and immunoregulation. The focus of this review is on currently novel advances about roles of CSL-dependent and independent Notch signaling pathways in cell apoptosis. The CSL can bind Notch intracellular domain (NIC) to act as a switch in mediating transcriptional activation or inactivation of the Notch signaling pathway downstream genes in the nucleus. It shows that CSL-dependent signaling regulates the cell apoptosis through Hes-1-PTEN-AKT-mTOR signaling, but rather the CSL-independent signaling mediates the cell apoptosis possibly via NIC-mTORC2-AKT-mTOR signaling, providing a new insight into apoptotic mechanisms.

Bee's honey attenuates non-alcoholic steatohepatitis-induced hepatic injury through the regulation of thioredoxin-interacting protein-NLRP3 inflammasome pathway.

PURPOSE: We aim to examine whether honey ameliorates hepatic injury in non-alcoholic steatohepatitis (NASH) animal and cell line steatosis models. METHODS: NASH was induced in female Sprague-Dawley rat by 8-week feeding with a high-fat diet. During the experiment, 5 g/kg honey was intragastrically fed daily. Rat normal hepatocyte BRL-3A cell was treated with sodium palmitate (SP) to induce steatosis in the absence or presence of honey pre-treatment or specific siRNA/overexpress plasmid of thioredoxin-interacting protein (TXNIP) or antagonist/agonist of Nod-like receptor protein 3 (NLRP3). RESULTS: Honey significantly improved the high-fat-diet-induced hepatic injury, steatosis, fibrosis, oxidative stress, and inflammation in rats. Honey also inhibited the overexpression of TXNIP and the activation of NLRP3 inflammasome. These effects were replicated in BRL-3A cell line which showed that the down-regulation of TXNIP or inhibition of NLRP3 contributed to the suppression of NLRP3 inflammasome activation, inflammation, and re-balanced lipid metabolism. In contrast, overexpression of TXNIP or agonism of NLRP3 exacerbated the cellular damage induced by SP. CONCLUSION: Suppression of the TXNIP-NLRP3 inflammasome pathway may partly contribute to the amelioration of hepatic injury during the progression of NASH by honey. Targeting hepatic TXNIP-NLRP3 inflammasome pathway is a potential therapeutic way for the prevention and treatment of NASH.

p38α subtype is a potential target to inhibit eNOS activity and NO production in human endothelial cells.

Human endothelial nitric oxide synthase (eNOS) activity is important for maintaining blood pressure homeostasis and vascular integrity through nitric oxide (NO).The in vitro study aimed at investigating a role of p38α signaling in modulating NO production in human umbilical vein endothelial cell-12 (HUVEC-12). Consistent with the stimulation of lipopolysaccharide (LPS) or tumor necrosis factor (TNF)-α, the over-expression of p38α markedly down-regulated the eNOS promoter activity in HUVEC-12, which could be reversed by its negative mutant p38α (AF) or p38-specific inhibitor SB203580. Compared to the stimulation of LPS or TNF-α, p38α-targeting siRNA decreased the expressions of phosphorylated and non-phosphorylated p38α, and increased the promoter activity, an eNOS mRNA level and a phosphorylated eNOS protein expression with the enhancement of NO, which could be abrogated by the scrambled siRNA. The in situ eNOS protein expression in the cells treated by p38α-targeting siRNA was also higher than that of the control, following the corresponding attenuation of a p38 level, and mainly localized in the inner membrane and cytoplasm. These results indicate that the p38α subtype may be a potential target to down-regulate the eNOS activity and NO production in human endothelial cells.

Sp1 modification of human endothelial nitric oxide synthase promoter increases the hypoxia-stimulated activity.

Human endothelial nitric oxide synthase (eNOS) gene has a TATA-less weak promoter with a low activity. The aim of this study was to increase eNOS promoter activity by modification. Human eNOS promoter was modified by inserting a Sp1 element at a -74 bp site and function of the modified promoter was investigated via a hypoxia model induced by cobalt chloride in human umbilical vein endothelial cells. The results demonstrated that the Sp1-modified promoter resulted in a significant increase of normalized luciferase activity in the presence of hypoxia. There was a correlation between the transcriptional activity of the Sp1-modified promoter and the level of eNOS expression with enhancement of nitric oxide production. Together, these data indicate that human eNOS promoter activity is increased by inserting Sp1 binding site into the GC-rich region of the promoter in response to hypoxia, suggesting that this provides an approach to ameliorate microcirculation barrier of some cardiovascular disease and to study its mechanistic process.

Ionomycin inhibits Jurkat T cell behaviors in the presence of phorbol-12,13-dibutyrate.

Ionomycin in conjunction with phorbol-12,13-dibutyrate (PDBu) is conventionally used as a stimulator to activate cells, especially original T cells. But we accidently found it had an entirely opposite action on malignant tumor cells derived from T cells. Thus, influence of ionomycin on human leukemia Jurkat T cell behaviors and its preliminary mechanistic process were explored in the presence of PDBu. Ionomycin could remarkably inhibit colony formation of the cells, and inhibitory rate of the cell proliferation was increased with ionomycin treatment in a dose- or time-related relationship, following the reduction of ERK1/2 and phosphorylated-ERK1/2 levels. However, a high dose of ionomycin might moderately repress mid-stage activation of the cells. It also blocked the cell entry at S-phase and G2/M-phase with the attenuation of transforming growth factor-ß (TGF-ß) level in the cells, and promoted the cell apoptosis following the augment of caspase-3 and cleaved caspase-3 in the cells. The dramatic elevation of [Ca2(+)]i and intracellular pH (pHi) was simultaneously followed by the above alteration of the cell behaviors. These results indicate that ionomycin may strongly inhibit human acute T lymphocyte leukemia progress in the presence of PDBu through the inhibition of ERK1/2 signaling, the activation of caspase-3 and the attenuation of TGF-ß mediated by the [Ca2(+)]i and pHi enhancement, providing a novel insight into function and potential application of both ionomycin and PDBu.

Disulfidptosis: a new form of programmed cell death.

Disulfidptosis, a new form of cell death triggered by disulfide stress, is characterized by the collapse of cytoskeleton proteins and F-actin due to the intracellular accumulation of disulfides. This discovery will eventually aid in the development of therapeutic strategies against cancer.

Regulatory roles of an atypical ubiquitin ligase UBE2O in orphans of multiprotein complexes for degradation.

UBE2O as an atypical ubiquitin-conjugating enzyme possesses an E2-E3 hybrid enzyme activity. It can regulate substrate levels or transcriptional activities by cooperating with other E3 ubiquitin ligases or forming homomeric complexes displaying intrinsic E2 and E3 activities. UBE2O controls the quality of cell proteome including protein degradation, modification, transport and location. Recent studies reveal that UBE2O plays a vital role in intracellular protein ubiquitination processes by regulating BMP/SMAD, TRAF/NF-κB, mTOR/HIF1a and IL-1ß/IRAK4 signaling pathways, c-Maf stability and BAP1 subcellular location, which is proposed as a quality control supervisor of multiprotein complexes for degradation. Its abnormality leads to a variety of physical activity disorders and even occurrence of cancer. UBE2O is entirely distinct in molecular structure and functions from other E2 ubiquitin ligase. Exploring and elucidating regulatory mechanism of UBE2O may identify novel crucial molecular targets so as to pave therapeutic approaches for ubiquitination-associated metabolic disorders and diseases. Here, we particularly feature regulatory pathways of UBE2O in orphans of multiprotein complexes for degradation and its potential application.

Corrigendum to "Characteristics of a novel photoinitiator aceanthrenequinone-initiated polymerization and cytocompatibility of its triggered polymer" [Toxicol. Rep. 9 (2022) 191-203].

[This corrects the article DOI: 10.1016/j.toxrep.2022.01.008.].

Characteristics of a novel photoinitiator aceanthrenequinone-initiated polymerization and cytocompatibility of its triggered polymer.

A number of photoinitiators are available in chemical industry, but less of them in biomedicine or clinical therapy due to the limitation of their cytotoxicity and biocompatibility. Thus, it is urgently necessary to find non-toxic or low-toxic photoinitiators to meet clinical demands. Aceanthrenequinone (AATQ) is a novel photosensitizer with high-photoinitiating ability, but no reports contribute, to date, to its cytotoxicity and biocompatibility. Here, primary cells and various cell lines were exposed to different concentrations of AATQ with or without irradiation. AATQ had the similar photoinitiating conversion efficiency to the extensively used bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (BAPO) and higher one than 9,10-phenanthrenequinone (PANQ) with the similar extent of polymerization in depth within a certain range, but displayed much lower cytotoxicity than BAPO under non-irradiation or irradiation. The biocompatibility of BisGMA/TEGDMA polymer prepared by AATQ was superior to that of PANQ, but inferior to that of camphorquinone (CQ) although the far lower dose of AATQ is enough to initiate polymerization of monomer than that of CQ. Hence, AATQ offers a valuable alternative in applications of industrial or biomedical areas.

Long non-coding RNA VAL facilitates PKM2 enzymatic activity to promote glycolysis and malignancy of gastric cancer.

BACKGROUND: Gastric cancer (GC) is one of the most common types of cancer worldwide, which leads to more than 10% of cancer-related deaths. Metabolism reprogramming presents as a pivotal event in cancer initiation and progression through enhancing aerobic glycolysis and anabolic metabolism. However, the underlying regulatory mechanisms in GC remain unknown. METHODS: VAL was identified by bioinformatics analyses in GC. Cell-based assays and mouse model illustrate the role of VAL in GC. RNA pull-down, immunoprecipitation assay and Western blot elucidate the interaction between VAL and PKM2. Pyruvate kinase activity, ECAR and OCR were measured to validate aerobic glycolysis of GC cells. RESULTS: Long non-coding RNA (lncRNA) VAL is significantly upregulated in GCs and indicates poor prognosis. Functional assays showed that VAL promotes GC malignant progression. Mechanistically, VAL strengthens the enzymatic activity of PKM2 and aerobic glycolysis of GC cells through directly binding with PKM2 to abrogate the PKM2-Parkin interaction, and to suppress Parkin-induced polyubiquitination of PKM2. In addition, glucose starvation induces VAL expression to enhance this process. CONCLUSIONS: Our study provides an insight into an lncRNA-dependent regulation on the enzymatic activity of PKM2, and suggests a potential of targeting VAL or PKM2 as promising biomarkers in GC diagnosis and treatment.

Degradable Hydrogel Adhesives with Enhanced Tissue Adhesion, Superior Self-Healing, Cytocompatibility, and Antibacterial Property.

Degradable hydrogel adhesives with multifunctional advantages are promising to be candidates as hemostatic agents, surgical sutures, and wound dressings. In this study, hydrogel adhesives are constructed by catechol-conjugated gelatin from natural resource, iron ions (Fe3+ ), and a synthetic polymer. Specifically, the latter is prepared by the radical ring-opening copolymerization of a cyclic ketene acetal monomer 5,6-benzo-2-methylene-1,3-dioxepane and N-(2-ethyl p-toluenesulfonate) maleimide. By the incorporation of ester bonds in the backbone and the combination with quaternary ammonium salt pendants in the polymer, it exhibits excellent degradability and antibacterial property. Remarkably, doping the synthetic polymer into the 3,4-dihydroxyphenylacetic acid-modified gelatin network forms a semi-interpenetrating polymer network which can effectively improve the rigidity, tissue adhesion, and antibacterial property of fabricated hydrogel adhesives. Moreover, non-covalent bonds from coordination interaction between catechol and Fe3+ contribute to the fast self-healing of the developed hydrogel adhesives. These hydrogel adhesives with the multiple merits including the degradability, enhanced tissue adhesion, superior self-healing, good cytocompatibility, and antibacterial property show the great potential to be used as tissue adhesives in biomedical fields.