First Report of Colletotrichum gloeosporioides Causing Leaf Blight on Cercis chinensis Bunge in China.

Cercis chinensis Bunge, commonly used as an ornamental plant, is native to southeastern China and extensively cultivated in gardens across major cities in the country. In August 2023, a new high-incidence disease was discovered at Huangshan University in Huangshan, Anhui Province, China. The symptoms initially began as small brown spots, which gradually expanded into large irregular brown spots with black-brown edges. The disease was investigated at both Jilingshan Park and Huangshan University, where C. chinensis Bunge was planted, revealing an average incidence rate of was 85 % at these sites. Seventy two leaf tissue samples (3 to 4 mm²) were collected from the margins of the lesion and subjected to surface sterilization with 75% ethanol for 30 seconds followed by 1% sodium hypochlorite for 90 seconds. Subsequently, the tissues were rinsed with sterile H2O, placed on potato dextrose agar (PDA) medium, and incubated at 25℃ for 5 days. The same fungus was isolated from 90% of the tissues, and pure cultures were obtained by monosporic isolation. Representative isolates ZJ 2-1, ZJ 2-2 and ZJ 2-3 were selected for morphological and molecular characterization. The colonies displayed a color range from white to gray, with white margins and aerial hyphae, while the reverse side of the colonies appeared gray to brown. Conidia were cylindrical, aseptate, with obtuse to slightly rounded ends, measuring 15.8±1.8×4.7±0.56 µm (n = 50). The morphological characteristics were generally consistent with those of Colletotrichum gloeosporioides species complex (Weir et al. 2012). Five conserved regions of isolates (ZJ 2-1, ZJ 2-2 and ZJ 2-3), including the internal transcribed spacer (ITS), glutamine synthase (GS), calmodulin (CAL), actin (ACT), and chitin synthase 1(CHS1) gene regions, were amplified using specific primers ITS1/ITS4 (Gardes et al. 1993), GSR1/GSF1 (Guerber et al. 2003), CL1C/CL2C (Li et al. 2018), ACT-512F/ACT-783R, and CHS-79F/CHS-345R (Zhu et al. 2019), respectively. Using the BLAST, ITS, GS, CAL, ACT and CHS1 gene sequences (GenBank accession nos. PP514751, PP448025, PP448026, PP448027 and PP448028, respectively) were 100% (594 out of 594 bp), 100% (864 out of 864 bp), 100% (299 out of 299 bp), 100% (732 out of 732 bp) and 100% (282 out of 282 bp) identical to C. gloeosporioides (GenBank accession nos. JX010152, JX010085, JX009818, JX009731 and JX009531, respectively). A Maximum Likelihood phylogenetic tree, constructed by combining all sequenced loci in MEGA7, showed that the isolates ZJ 2-1, ZJ 2-2 and ZJ 2-3 clustered within the C. gloeosporioides clade with 99% bootstrap support (Fig. S1). To fulfill Koch's postulates, five C. chinensis Bunge plants were tested for pathogenicity in the field with isolates ZJ 2-1, ZJ 2-2 and ZJ 2-3 at Huangshan University. Twelve leaves from each tree were wounded and inoculated with mycelial plugs (approximately 4 mm in diameter) and 10 µl of a spore suspension (1.0 × 106 conidia/ml) of C. gloeosporioides. Inoculation with sterile PDA plugs and pure water on leaves of each tree served as negative controls. Plastic bags were used to wrap the leaves, and sterile H2O was sprayed into the bags to maintain moisture conditions (Zhang et al.2020). The experiment was repeated two times, and within 5 days, all inoculated points displayed lesions similar to those observed in the field, whereas controls remained asymptomatic (Fig. S2). The same fungus was reisolated from these lesions with a frequency of 100%. Consequently, the pathogen responsible the disease in C. chinensis Bunge was identified as C. gloeosporioides. To the best of our knowledge, this is the first report of C. gloeosporioides causing leaf blight on C. chinensis Bunge in China. This study provides valuable insights for implementing targeted measures to control leaf blight on C. chinensis Bunge and lays a foundation for the prevention and treatment of the disease.

AXL antibody and AXL-ADC mediate antitumor efficacy via targeting AXL in tumor-intrinsic epithelial-mesenchymal transition and tumor-associated M2-like macrophage.

The receptor tyrosine kinase AXL is an emerging driver of cancer recurrence, while its molecular mechanism remains unclear. In this study we investigated how AXL regulated the disease progression and poor prognosis in non-small cell lung cancer (NSCLC) and triple negative breast cancer (TNBC). We performed AXL transcriptome analysis from TCGA datasets, and found that AXL expression was significantly elevated in NSCLC and TNBC correlating with poor prognosis, epithelial-mesenchymal transition (EMT) and immune-tolerant tumor microenvironment (TME). Knockdown of AXL or treatment with two independent AXL antibodies (named anti-AXL and AXL02) all diminished cell migration and EMT in AXL-high expressing NSCLC and TNBC cell lines. In a mouse model of 4T1 TNBC, administration of anti-AXL antibody substantially inhibited lung metastases formation and growth, accompanied by reduced downstream signaling activation, EMT and proliferation index, as well as an increased apoptosis and activated anti-tumor immunity. We found that AXL was abundantly activated in tumor nodule-infiltrated M2-macrophages. A specific anti-AXL antibody blocked bone marrow-derived macrophage (BMDM) M2-polarization in vitro. Targeting of AXL in M2-macrophage in addition to tumor cell substantially suppressed CSF-1 production and eliminated M2-macrophage in TME, leading to a coordinated enhancement in both the innate and adaptive immunity reflecting M1-like macrophages, mature dendritic cells, cytotoxic T cells and B cells. We generated a novel and humanized AXL-ADC (AXL02-MMAE) employing a site-specific conjugation platform. AXL02-MMAE exerted potent cytotoxicity against a panel of AXL-high expressing tumor cell lines (IC50 < 0.1 nmol/L) and suppressed in vivo growth of multiple NSCLC and glioma tumors (a minimum efficacy dose<1 mg/kg). Compared to chemotherapy, AXL02-MMAE achieved a superior efficacy in regressing large sized tumors, eliminated AXL-H tumor cell-dependent M2-macrophage infiltration with a robust accumulation of inflammatory macrophages and mature dendritic cells. Our results support AXL-targeted therapy for treatment of advanced NSCLC and TNBC.

[Medication rules of Chinese herbal compound prescriptions for treating angina in national patent database based on multiple data mining].

This study explored the medication rules of Chinese herbal compound prescriptions for the treatment of angina based on the Chinese herbal compound patents in the patent database of the China National Intellectual Property Administration. The data of eligible Chinese herbal compound patents for the treatment of angina were collected from the patent database of the China National Intellectual Property Administration from database inception to November 10, 2022, and subjected to data modeling, analysis of main syndromes, medication frequency analysis, cluster analysis, association rule analysis, and data visualization by using Excel 2021, IBM SPSS Statistics 26.0, IBM SPSS Modeler 18.0, Cytoscape 3.9.1, and Rstudio R 4.2.2.2 to explore the medication rules for angina. The study included 636 pieces of patent data for angina that met the inclusion criteria, involving 815 drugs, with a total frequency of 6 586. The most common main syndromes were blood stasis obstructing the heart syndrome(222, 34.91%) and Qi deficiency and blood stasis syndrome(112, 17.61%). The top 10 most frequently used drugs were Salviae Miltiorrhizae Radix et Rhizoma, Chuanxiong Rhizoma, Notoginseng Radix et Rhizoma, Astragali Radix, Angelicae Sinensis Radix, Carthami Flos, Glycyrrhizae Radix et Rhizoma, Ginseng Radix et Rhizoma, Borneolum Syntheticum, and Corydalis Rhizoma. High-frequency drugs included blood-activating and stasis-resolving drugs(1 197, 18.17%) and deficiency-tonifying drugs(809, 12.28%). Cluster analysis identified eight drug combinations, including five new prescriptions suitable for clinical use and new drug development, and three drug pairs. The core drug combination of Salviae Miltiorrhizae Radix et Rhizoma-Chuanxiong Rhizoma-Carthami Flos was identified through the complex co-occurrence network analysis of Chinese medicines. Association rule analysis yielded a total of 17 rules, including 13 drug pairs and 4 tripartite combinations. Common drug pairs included Salviae Miltiorrhizae Radix et Rhizoma-Chuanxiong Rhizoma(support degree 25.79%, confidence coefficient 69.49%, lift 1.30) and Salviae Miltiorrhizae Radix et Rhizoma-Notoginseng Radix et Rhizoma(support degree 22.01%, confidence coefficient 61.95%, lift 1.16). Common tripartite combinations included Salviae Miltiorrhizae Radix et Rhizoma-Chuanxiong Rhizoma-Astragali Radix(support degree 10.85%, confidence coefficient 73.40%, lift 1.37) and Salviae Miltiorrhizae Radix et Rhizoma-Chuanxiong Rhizoma-Notoginseng Radix et Rhizoma(support degree 10.69%, confidence coefficient 79.07%, lift 1.48). The results showed that the underlying pathogenesis of angina involved blood stasis obstructing the heart and Qi deficiency and blood stasis. The overall nature of the disease was characterized as asthenia in origin and sthenia in superficiality. In the prescription formulation, blood-activating and stasis-resolving drugs, such as Salviae Miltiorrhizae Radix et Rhizoma, Chuanxiong Rhizoma, and Carthami Flos were often used to resolve the excess manifestation, which were combined with tonifying drugs such as Astragali Radix, Angelicae Sinensis Radix, Glycyrrhizae Radix et Rhizoma, and Ginseng Radix et Rhizoma to reinforce the deficiency. The syndrome, pathogenesis, disease nature, and medication were consistent with clinical practice. Additionally, the new compound prescriptions and drug combinations derived from the multiple data mining in this study could provide references and insights for the clinical diagnosis and treatment of angina and the development of new drugs.

Gold Nanoparticle-Based Photo-Cross-Linking Strategy for Cellular Target Identification of Supercomplex Molecular Systems.

Cellular target identification plays an essential role in innovative drug development and pharmacological mechanism elucidation. However, very few practical experimental methodologies have been developed for identifying target proteins for supercomplex molecular systems such as biologically active phytochemicals or pharmaceutical compositions. To overcome this limitation, we synthesized gold nanoparticles (AuNPs) as solid scaffolds, which were bound with 4,4'-dihydroxybenzophenone (DHBP) as a photo-cross-linking group on the surface. Then, DHBP-modified AuNPs cross-linked various organic compounds from phytochemicals under ultraviolet radiation via carbene reactions, H-C bond insertion, for catalytic C-C bond formation. We next used the phytochemical-cross-linked AuNPs (phytoAuNPs) to pull down potential binding proteins from brain tissue lysate and identified 13 neuroprotective targets by mass spectrometry analysis. As an exemplary study, we selected Hsp60 as a crucial cellular target to further screen 14 target-binding compounds from phytochemicals through surface plasmon resonance (SPR) analysis, followed by Hsp60 activity detection and neuroprotective effect assay in cells. Collectively, this gold nanoparticle-based photo-cross-linking strategy can serve as a useful platform for discovering novel cellular targets for supercomplex molecular systems and help to explore pharmacological mechanisms and active substances.

An effective method to reduce lymphatic drainage post-lateral cervical lymph node dissection of differentiated thyroid cancer: a retrospective analysis.

BACKGROUND: Lymph or chyle leak (LL/CL) is severe complications after lateral cervical lymph node dissection (LLND), mainly due to iatrogenic injury of the lymphatic duct. Efficient and well-operated methods to reduce postoperative drainage are still lacking. This was a feasibility study to evaluate a new method of preventing LL/CL compared to conventional treatment. METHOD: We retrospectively analyzed 20 consecutive patients who used the "pedicled omohyoid flap covering (POFC)" method during LLND from January 2019 to December 2021 in our center as an observation group. Another 20 consecutive patients used the conventional method during LLND in this period as a control group. The clinical and pathological features of the two groups were compared, and the related factors that affected postoperative lymphatic drainage were analyzed with Cox proportional hazards models. RESULTS: The drainage volume per 24 h and the incidence of LL/CL in the control group were both higher than that in the observation group (all P < 0.05), and the number of lymph nodes dissected in the IV region > 10 and the use of the POFC method were the independent risk factors that significantly affected the incidence of LL/CL post LLND (all P < 0.05). CONCLUSIONS: POFC is a safe and useful method for reducing drainage and preventing LL/CL post-LLND, especially for patients with heavy metastasis of the lymph nodes in the IV region.

Discovery of MTR-106 as a highly potent G-quadruplex stabilizer for treating BRCA-deficient cancers.

G-quadruplexes (G4s) are DNA or RNA structures formed by guanine-rich repeating sequences. Recently, G4s have become a highly attractive therapeutic target for BRCA-deficient cancers. Here, we show that a substituted quinolone amide compound, MTR-106, stabilizes DNA G-quadruplexes in vitro. MTR-106 displayed significant antiproliferative activity in homologous recombination repair (HR)-deficient and PARP inhibitor (PARPi)-resistant cancer cells. Moreover, MTR-106 increased DNA damage and promoted cell cycle arrest and apoptosis to inhibit cell growth. Importantly, its oral and i.v. administration significantly impaired tumor growth in BRCA-deficient xenograft mouse models. However, MTR-106 showed modest activity against talazoparib-resistant xenograft models. In rats, the drug rapidly distributes to tissues within 5 min, and its average concentrations were 12-fold higher in the tissues than in the plasma. Overall, we identified MTR-106 as a novel G-quadruplex stabilizer with high tissue distribution, and it may serve as a potential anticancer agent.

A new BET inhibitor, 171, inhibits tumor growth through cell proliferation inhibition more than apoptosis induction.

The bromodomain and extra-terminal domain (BET) family of proteins, especially bromodomain-containing protein 4 (BRD4), has emerged as exciting anti-tumor targets due to their important roles in epigenetic regulation. Therefore, the discovery of BET inhibitors with promising anti-tumor efficacy will provide a novel approach to epigenetic anticancer therapy. Recently, we discovered the new BET inhibitor compound 171, which is derived from a polo-like kinase 1 (PLK1)-BRD4 dual inhibitor based on our previous research. Compound 171 was found to maintain BET inhibition ability without PLK1 inhibition, and there was no selectivity among BET family members. The in vitro and in vivo results both indicated that the overall anti-tumor activity of compound 171 was improved compared with the (+)-JQ-1 or OTX-015 BET inhibitors. Furthermore, we found that compound 171 could regulate the expression of cell cycle-regulating proteins including c-Myc and p21 and induce cell cycle arrest in the G0/G1 phase. However, compound 171 only has a quite limited effect on apoptosis, in considering that apoptosis was only observed at doses greater than 50 µM. To determine the mechanisms underlying cell death, proliferation activity assay was conducted. The results showed that compound 171 induced clear anti-proliferative effects at doses that no obvious apoptosis was induced, which indicated that the cell cycle arresting effect contributed mostly to its anti-tumor activity. The result of this study revealed the anti-tumor mechanism of compound 171, and laid a foundation for the combination therapy in clinical practice, if compound 171 or its series compounds become drug candidates in the future.

Author Correction: Targeting Hsp90 with FS-108 circumvents gefitinib resistance in EGFR mutant non-small cell lung cancer cells.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

[Neuroprotective effects and mechanism of ethanol extract of Cistanche tubulosa against oxygen-glucose deprivation/reperfusion].

To investigate the inhibitory effects and mechanism of Cistanche tubulosa ethanol extract( CTEE) against oxygen-glucose deprivation/reperfusion( OGD/R)-induced PC12 cells neuronal injury. In this study,OGD/R-induced PC12 cells were used to explore the neuroprotective effects of CTEE( 12. 5,25,50 mg·L-1) by detecting cell viability with MTT assay,apoptosis with AO/EB and Hoechst 33258,mitochondrial membrane potential changes with JC-1 staining,mitochondrial oxidative stress with MitoSOX staining,as well as the apoptosis-related protein expression( PARP,cleaved PARP,caspase-3,cleaved caspase-3,Bax,Bcl-2) with Western blot. RESULTS:: showed that CTEE effectively protected OGD/R-induced neuronal injury and increased the survival rate of PC12 cells.AO/EB and Hoechst 33258 staining showed that CTEE could effectively inhibit apoptosis. Moreover,JC-1 and MitoSOX staining results showed that CTEE decreased mitochondrial stress and mitochondrial membrane potential imbalance in PC12 cells in a concentration-dependent manner. Meanwhile,CTEE could obviously suppress the activation of key proteins in mitochondrial apoptosis pathway such as caspase-3 and PARP,and significantly inhibit the rise of Bax and down-regulation of Bcl-2. In conclusion,CTEE has obvious protective effects on OGD/R-induced PC12 cells neuronal injury,potentially via inhibiting mitochondrial oxidative stress and apoptosis-related signaling pathway.

TINCR facilitates non-small cell lung cancer progression through BRAF-activated MAPK pathway.

Long non-coding RNAs are critically involved in oncogenesis in various cancer types. Here we reported a novel lncRNA signature correlated with progression of non-small cell lung cancer (NSCLC). In particular, we identified elevated expression of terminal differentiation-induced noncoding RNA (TINCR) in human NSCLC samples, which were associated with enhanced migration, viability in NSCLC cells in vitro. Higher TINCR level was also correlated with poor survival. Furthermore, TINCR increased xenograft tumor growth in vivo mouse models. Mechanistic study demonstrated that TINCR can interact with BRAF to facilitate its kinase activity, thereby leading to activation of oncogenic mitogen-activated protein kinase (MAPK) pathway. These results suggested that TINCR upregulation may signal through the MAPK pathway to promote NSCLC tumorigenesis. Therefore, TINCR may serve as a potential prognostic marker and therapeutic target for NSCLC patients.

Association between body mass index and health-related quality of life among Chinese elderly-evidence from a community-based study.

BACKGROUND: This study aimed to explore the effects of (body mass index) BMI on health related quality of life (HRQoL) among the elderly in Jiangsu, China. METHODS: A total of 10,257 community dwelling elderly (≥60 years old) were enrolled in a cross-sectional study. HRQoL was measured via the Eq-5d-3 L. Chi-square tests and one-way ANOVA analyses were used to compare the frequencies and scores of Eq-5d responses among different BMI groups (defined as "underweight", "normal weight", "overweight" and "obese"). Logistic regression analyses were conducted to examine the associations between BMI and HRQoL. RESULTS: Among the subjects, the proportion of "normal weight", "underweight", "overweight" and "obese" were 66.0, 8.3, 23.1, and 2.6%, respectively. The score of the Eq-5d index among total participants was 0.8036 and the Visual Analog Scale (VAS) score was 75.47. For both the responses frequency and scores of Eq-5d-3 L, there were significant differences among BMI groups (P < 0.001). The Logistic regression model showed that both in men and women, underweight elderly were more likely to suffer low HRQoL. The adjusted odds ratio (OR) with a 95% confidence interval (CI) for Eq-5d index/VAS was 2.03 (1.48, 2.79)/1.83 (1.34, 2.50) in men and 1.47(1.09,1.98)/1.52(1.20,1.91) in women. Overweight women more likely to have a low Eq-5d index, while overweight men were less likely to have a low Eq-5d VAS. CONCLUSION: This study shows that underweight is an explicit risk factor of low HRQoL in both the male and female elderly, while the effect of overweight on low HRQoL varies slightly by gender.

Palladium-Catalyzed Synthesis of α-Iminonitriles from Aryl Halides via Isocyanide Double Insertion Reaction.

An efficient one-pot synthesis of α-iminonitriles from readily available aryl halides via palladium-catalyzed double isocyanide insertion and elimination has been developed, without using various hypertoxic cyanides and excess oxidants. Furthermore, the utility of this reaction was demonstrated by the rapid total synthesis of quinoxaline and the reaction of functional groups exchanged with aryl halides.

NMR-based platform for fragment-based lead discovery used in screening BRD4-targeted compounds.

AIM: Fragment-based lead discovery (FBLD) is a complementary approach in drug research and development. In this study, we established an NMR-based FBLD platform that was used to screen novel scaffolds targeting human bromodomain of BRD4, and investigated the binding interactions between hit compounds and the target protein. METHODS: 1D NMR techniques were primarily used to generate the fragment library and to screen compounds. The inhibitory activity of hits on the first bromodomain of BRD4 [BRD4(I)] was examined using fluorescence anisotropy binding assay. 2D NMR and X-ray crystallography were applied to characterize the binding interactions between hit compounds and the target protein. RESULTS: An NMR-based fragment library containing 539 compounds was established, which were clustered into 56 groups (8-10 compounds in each group). Eight hits with new scaffolds were found to inhibit BRD4(I). Four out of the 8 hits (compounds 1, 2, 8 and 9) had IC50 values of 100-260 µmol/L, demonstrating their potential for further BRD4-targeted hit-to-lead optimization. Analysis of the binding interactions revealed that compounds 1 and 2 shared a common quinazolin core structure and bound to BRD4(I) in a non-acetylated lysine mimetic mode. CONCLUSION: An NMR-based platform for FBLD was established and used in discovery of BRD4-targeted compounds. Four potential hit-to-lead optimization candidates have been found, two of them bound to BRD4(I) in a non-acetylated lysine mimetic mode, being selective BRD4(I) inhibitors.

Targeting Hsp90 with FS-108 circumvents gefitinib resistance in EGFR mutant non-small cell lung cancer cells.

AIM: Inhibition of heat shock protein (Hsp90) has been proven to be effective in overriding primary and acquired resistance of kinase inhibitors. In this study, we investigated the role of FS-108, a newly developed Hsp90 inhibitor, to overcome gefitinib resistance in EGFR mutant non-small cell lung cancer cells. METHODS: Cell proliferation was assessed using the SRB assay. Cell cycle distribution and apoptosis were analyzed by flow cytometry. Protein expression was examined by Western blotting. The in vivo effectiveness of FS-108 was determined in an NCI-H1975 subcutaneous xenograft model. RESULTS: FS-108 triggered obvious growth inhibition in gefitinib-resistant HCC827/GR6, NCI-H1650 and NCI-H1975 cells through inducing G2/M phase arrest and apoptosis. FS-108 treatment resulted in a remarkable degradation of key client proteins involved in gefitinib resistance and further abrogated their downstream signaling pathways. Interestingly, FS-108 alone exerted an identical or superior effect on circumventing gefitinib resistance compared to combined kinase inhibition. Finally, the ability of FS-108 to overcome gefitinib resistance in vivo was validated in an NCI-H1975 xenograft model. CONCLUSION: FS-108 is a powerful agent that impacts the survival of gefitinib-resistant cells in vitro and in vivo through targeting Hsp90.

Discovery of a new series of imidazo[1,2-a]pyridine compounds as selective c-Met inhibitors.

AIM: Aberrant c-Met activation plays a critical role in cancer formation, progression and dissemination, as well as in development of resistance to anticancer drugs. Therefore, c-Met has emerged as an attractive target for cancer therapy. The aim of this study was to develop new c-Met inhibitors and elaborate the structure-activity relationships of identified inhibitors. METHODS: Based on the predicted binding modes of Compounds 5 and 14 in docking studies, a new series of c-Met inhibitor-harboring 3-((1H-pyrrolo[3,2-c]pyridin-1-yl)sulfonyl)imidazo[1,2-a]pyridine scaffolds was discovered. Potent inhibitors were identified through extensive optimizations combined with enzymatic and cellular assays. A promising compound was further investigated in regard to its selectivity, its effects on c-Met signaling, cell proliferation and cell scattering in vitro. RESULTS: The most potent Compound 31 inhibited c-Met kinase activity with an IC50 value of 12.8 nmol/L, which was >78-fold higher than those of a panel of 16 different tyrosine kinases. Compound 31 (8, 40, 200 nmol/L) dose-dependently inhibited the phosphorylation of c-Met and its key downstream Akt and ERK signaling cascades in c-Met aberrant human EBC-1 cancer cells. In 12 human cancer cell lines harboring different background levels of c-Met expression/activation, Compound 31 potently inhibited c-Met-driven cell proliferation. Furthermore, Compound 31 dose-dependently impaired c-Met-mediated cell scattering of MDCK cells. CONCLUSION: This series of c-Met inhibitors is a promising lead for development of novel anticancer drugs.

[Progress in the study of small molecule inhibitors of HSP90].

HSP90, which is the biomarker of cell stress and endogenous protective protein, functions as a molecular chaperone. Many client proteins of HSP90, including EGFR, Met, Raf-1, IKK and p53, play important roles in the occurrence and development of tumor. Binding of HSP90 inhibitors triggers the deactivation of HSP90, resulting in client protein degradation, and hence inhibits the tumor growth by blocking multiple targets involved in signaling of tumor proliferation. This review summarizes recent development of small molecule inhibitors bound to N-terminal of HSP90.

ER membrane remodeling by targeting RTN4 induces pyroptosis to facilitate antitumor immune.

Pyroptosis is an identified programmed cell death that has been highly linked to endoplasmic reticulum (ER) dynamics. However, the crucial proteins for modulating dynamic ER membrane curvature change that trigger pyroptosis are currently not well understood. In this study, a biotin-labeled chemical probe of potent pyroptosis inducer α-mangostin (α-MG) was synthesized. Through protein microarray analysis, reticulon-4 (RTN4/Nogo), a crucial regulator of ER membrane curvature, was identified as a target of α-MG. We observed that chemically induced proteasome degradation of RTN4 by α-MG through recruiting E3 ligase UBR5 significantly enhances the pyroptosis phenotype in cancer cells. Interestingly, the downregulation of RTN4 expression significantly facilitated a dynamic remodeling of ER membrane curvature through a transition from tubules to sheets, consequently leading to rapid fusion of the ER with the cell plasma membrane. In particular, the ER-to-plasma membrane fusion process is supported by the observed translocation of several crucial ER markers to the "bubble" structures of pyroptotic cells. Furthermore, α-MG-induced RTN4 knockdown leads to PKM2-dependent conventional caspase-3/GSDME cleavages for pyroptosis progression. In vivo, we observed that chemical or genetic RTN4 knockdown significantly inhibited cancer cells growth, which further exhibited an antitumor immune response with anti-PD-1. In translational research, RTN4 high expression was closely correlated with the tumor metastasis and death of patients. Taken together, RTN4 plays a fundamental role in inducing pyroptosis through the modulation of ER membrane curvature remodeling, thus representing a prospective druggable target for anticancer immunotherapy.

Growth inhibitory effects and molecular mechanisms of crotoxin treatment in esophageal Eca-109 cells and transplanted tumors in nude mice.

AIM: To investigate the antitumor actions of the Crotalus durissus neurotoxin (crotoxin) on human esophageal carcinoma (Eca-109) cells in vitro and transplanted esophageal Eca-109 tumors in nude mice. METHODS: The growth-inhibitory effect was analyzed in Eca-109 cells using MTT assay. Cell morphology changes in nuclei were observed using Hoechst 33342 staining, while apoptosis and cell cycle distribution were examined by flow cytometry. RT-PCR was used to measure the Bcl-2, p15, and caspase-3 p17 gene expression levels. A tumor transplantation model was established by inoculation of Eca-109 cells were into female Balb/c nude mice. Crotoxin (25, 50, and 100 mg/kg) was subcutaneously injected into the transplanted tumors every 2 d for a total of 10 injections. Tumor size and weight were measured. Bcl-2, p15, and caspase-3 p17 protein expression in transplanted tumors was analyzed using Western blotting. RESULTS: Crotoxin (25, 50, and 100 µg/mL) inhibited the growth of Eca-109 cells in a dose-dependent manner with inhibition rates of 22.9%, 35.8%, and 57.2%, respectively. Hoechst 33342 staining revealed apoptotic cells with pyknotic nuclear chromatin after crotoxin treatment. In Eca-109 cells, crotoxin induced apoptosis and G1 block, significantly upregulated the expression of p15 and caspase-3 p17 genes and downregulated the expression of Bcl-2 gene. Furthermore, crotoxin inhibited the growth of Eca-109 tumors in nude mice in a dose-dependent manner. Western blotting showed that crotoxin increased p15 and caspase-3 p17 protein levels and reduced Bcl-2 protein level in tumor specimens. CONCLUSION: Crotoxin inhibits the growth of Eca-109 cells in vitro via apoptosis induction and G1 block. Local administration of crotoxin inhibits the growth of subcutaneously transplanted Eca-109 cells in nude mice, possibly via increasing p15 and caspase-3 p17 protein expression and reducing Bcl-2 protein expression.

Design, synthesis and biological evaluation of bivalent ligands against A(1)-D(1) receptor heteromers.

AIM: To design and synthesize bivalent ligands for adenosine A1-dopamine D1 receptor heteromers (A1-D1R), and evaluate their pharmacological activities. METHODS: Bivalent ligands and their corresponding A1R monovalent ligands were designed and synthesized. The affinities of the bivalent ligands for A1R and D1R in rat brain membrane preparation were examined using radiolabeled binding assays. To demonstrate the formation of A1-D1R, fluorescence resonance energy transfer (FRET) was conducted in HEK293 cells transfected with D1-CFP and A1-YFP. Molecular modeling was used to analyze the possible mode of protein-protein and protein-ligand interactions. RESULTS: Two bivalent ligands for A1R and D1R (20a, 20b), as well as the corresponding A1R monovalent ligands (21a, 21b) were synthesized. In radiolabeled binding assays, the bivalent ligands showed affinities for A1R 10-100 times higher than those of the corresponding monovalent ligands. In FRET experiments, the bivalent ligands significantly increased the heterodimerization of A1R and D1R compared with the corresponding monovalent ligands. A heterodimer model with the interface of helixes 3, 4, 5 of A1R and helixes 1, 6, 7 from D1R was established with molecular modeling. The distance between the two ligand binding sites in the heterodimer model was approximately 48.4 Å, which was shorter than the length of the bivalent ligands. CONCLUSION: This study demonstrates the existence of A1-D1R in situ and a simultaneous interaction of bivalent ligands with both the receptors.

Synthesis and bioassay of ß-(1,4)-D-mannans as potential agents against Alzheimer's disease.

AIM: Oligomannurarate 971 derived from a marine plant has shown neuroprotective effects. In this study we synthesized a series of truncated derivatives of the oligosaccharide, and investigated the effect of these derivatives against Aß peptide toxicity in vitro. METHODS: The sulfoxide method was applied to synthesize the derivatives. SH-SY5Y human neuroblastoma cells were treated with Aß1-40 (2 µmol/L), and the cell viability was detected using a CCK8 assay. RESULTS: A series of ß-(1,4)-D-mannosyl oligosaccharide, ranging from the disaccharide to the hexasaccharide, were synthesized. Addition of 10 µmol/L ß-(1,4)-D-mannobiose 6, ß-(1,4)-D-mannotriose 9 or ß-(1,4)-D-mannotetraose 12 in SH-SY5Y cells significantly attenuated Aß1-40-induced toxicity. The efficacies were similar to those caused by 10 µmol/L oligomannurarate 971 or alzhemed. Other oligosaccharides including oligomaltoses and oligocelluloses were less active. CONCLUSION: Synthetic homogeneous short chain ß-(1,4)-D-mannans shows neuroprotective effect against Aß peptide toxicity similar to that of heterogeneous oligomannurarate 971 and alzhemed.