Preparation and p-phenylenediamine detection mechanism of a dialdehyde cellulose and a 7-amino-4-methylcoumarin-based fluorescent probe.

A novel fluorescent probe, fluorescent dialdehyde cellulose (FDAC), was prepared to detect p-phenylenediamine (PPD) in water samples conveniently and quickly. This was achieved by grafting 7-amino-4-methylcoumarin (AMC) onto dialdehyde cellulose (DAC) via an aldol-amine condensation reaction. This method is greener, more economical, and simpler than existing methods for preparing fluorescent probes. The probe was found to be more effective for PPD detection in polar solvents, with less interference from pH and other compounds present in the sample matrix. The photoluminescence of FDAC at λex/λem = 340/430 nm was statically quenched by PPD, allowing for accurate detection within the range of 10-100 µmol/L under optimal conditions, with a detection limit of 3.2 µmol/L (3 σ/s). Meanwhile, the Schiff base (-C=N- group) generated by the condensation of DAC and AMC increased the reaction activity of the fluorescent moiety and changed the AMC conjugated structure, making FDAC more susceptible to aminolysis with PPD than AMC. This study presents a promising solution for fluorescence detection of aniline compounds, with significant potential for application in fields such as environmental analysis.

BTN3A1 promotes tumor progression and radiation resistance in esophageal squamous cell carcinoma by regulating ULK1-mediated autophagy.

Radiotherapy is one of the most effective treatments for esophageal squamous cell carcinoma (ESCC); however, radioresistance is a clinical problem that must urgently be solved. Here, we found that butyrophilin subfamily 3 member A1 (BTN3A1) is upregulated in ESCC tumor tissues compared with nontumor tissues. We also evaluated BTN3A1 expression in patients with ESCC receiving adjuvant radiotherapy. The results demonstrated that BTN3A1 upregulation predicts a poor prognosis for ESCC patients. BTN3A1 overexpression promotes ESCC cell proliferation in vitro and in vivo. Moreover, BTN3A1 knockdown sensitized ESCC cells to radiation. We further explored the mode of death involved in BTN3A1-mediated radioresistance. Previous studies have shown that apoptosis, autophagy, necrosis, pyroptosis and ferroptosis are important for the survival of ESCC cells. We performed an RT-PCR array and western blotting (WB) to identify the mode of death and revealed for the first time that BTN3A1 promotes cell radioresistance by activating autophagy. In addition, by performing immunoprecipitation and mass spectrometry analyses, we found that BTN3A1 regulated the expression of UNC-51-like autophagy activating kinase 1(ULK1) and promoted its phosphorylation to subsequently initiate autophagy. Chromatin immunoprecipitation (ChIP) and luciferase reporter assay results indicated that BTN3A1 is a novel direct target of hypoxia inducible factor-1α (HIF-1α). HIF-1α, a transcription factor, promotes BTN3A1 transcription upon irradiation. Overall, the present study is the first to show that BTN3A1 plays a key role in radioresistance and that targeting BTN3A1 might be a promising strategy to improve radiotherapy efficacy in patients with ESCC.

Ferric ion detection mechanism of a dicarboxylic cellulose nanocrystal and a 7-amino-4-methylcoumarin based fluorescent chemosensor.

As one of Earth's most widely distributed and abundant elements, iron impacts the natural environment and biological systems. Therefore, developing a simple, rapid, and accurate Fe3+ detection method is vital. Fluorescent dicarboxylic cellulose nanocrystals (FDCN) with selective quenching of Fe3+ were synthesized using 7-amino-4-methylcoumarin (AMC), and dicarboxylic cellulose nanocrystals (DCN) prepared by sequential periodate-chlorite oxidation. The sensing characteristics and detection mechanism of FDCN for Fe3+ were studied by fluorescence spectrophotometry, Fourier-transform infrared spectroscopy (FTIR), the Stern-Volmer equation, Job's plot method, and the Benesi-Hildebrand equation. The results showed that FDCN was highly selective for Fe3+, and other metal ions did not reduce the selectivity. High sensitivity with a detection limit of 0.26 µM and a Stern-Volmer quenching constant of 0.1229 were also achieved. The coordination between Fe3+ and the carboxylic, hydroxyl, and amide groups on the surface of FDCN and the carbonyl of coumarin lactones to form FDCN/Fe3+ complexes prevented the intramolecular charge transfer (ICT) process and led to the fluorescence quenching of FDCN. EDTA restored the fluorescence emission of quenched FDCN. The complexation stoichiometry of Fe3+ to FDCN was 1 : 1, and the association constant was 3.23 × 104 M-1. The high hydrophilicity, sensitivity, and selectivity of FDCN for Fe3+ make the chemosensor suitable for Fe3+ trace detection in drinking water and biology.

SPP1 promotes radiation resistance through JAK2/STAT3 pathway in esophageal carcinoma.

BACKGROUND: Therapeutic resistance to radiotherapy is one of the major obstacles in clinical practice that significantly affect the therapeutic efficiency and prognosis of human esophageal carcinoma (ESCA). Thus, it is critical to understand the molecular mechanisms of radiation resistance in ESCA. Secreted phosphoprotein 1 (SPP1) plays an essential role in various human cancers, but its role in radiation resistance remains unclear. METHOD: Cell culture and transfection; Cell Counting Kit-8 (CCK-8) assays; EdU incorporation assays; Patient sample collection and medical records review; Transwell assays; Colony formation assays; Wound healing assays; Western blot; Immunofluorescence; Immunohistochemistry; Irradiation; Flow cytometry; Animal studies; Human Apoptosis Array Kit; Bioinformatics. RESULT: In the current study, we reported the novel phenomenon that radiation-treated human ESCA cells upregulated SPP1 expression, which in turn contributed to the ESCA resistance to radiotherapy. We also reported the tumor-promoting effect of SPP1 in ESCA systematically and comprehensively. Furthermore, subsequent studies by knocking down or overexpressing SPP1 in human ESCA cells showed that SPP1 could facilitate the repair of DNA damage and the survival of tumor cells post-radiation in ESCA, which might contribute to the development of radiation resistance during the radiotherapy process. More detailed investigations on the downstream molecular pathway suggested that radiation could increase the phosphorylation level of JAK2 and STAT3 by increasing SPP1 expression. Further in vivo validation using a mouse ESCA xenograft model showed that SPP1 overexpression significantly increased tumor volume while either SPP1 knockdown or pharmacological inhibition of the JAK2-STAT3 pathway reduced tumor volume in a synergistic manner with radiotherapy. CONCLUSION: Collectively, these findings suggested that the SPP1/JAK2/STAT3 axis is a critical player in ESCA progression and radiation resistance, which is a potential therapeutic target for combined therapy with the standard radiotherapy regimen to improve curative effect and increase patients' survival with ESCA.

Hafnium-Based Metal-Organic Framework Nanoparticles as a Radiosensitizer to Improve Radiotherapy Efficacy in Esophageal Cancer.

Radiotherapy is one of the most widely used clinical treatments for tumors, but it faces limitations, such as poor X-ray retention at the tumor site. The use of radiosensitizers containing high Z elements is an effective way to enhance X-ray absorption. Here, we demonstrate a simple one-step method for the synthesis of UiO-66-NH2(Hf) metal-organic framework nanoparticles for use as radiosensitizers in radiotherapy. The UiO-66-NH2(Hf) nanoparticles had a diameter of less than 100 nm and were stable in the physiological environment. UiO-66-NH2(Hf) induced apoptosis by enhancing X-ray absorption, as confirmed by in vitro and in vivo experiments. These characteristics make UiO-66-NH2(Hf) a promising radiosensitizer for esophageal cancer radiotherapy.

RAD001 targeted HUVECs reverses 12-lipoxygenase-induced angiogenesis in oesophageal squamous cell carcinoma.

12-LOX plays an important role in the progression of various malignancies. However, the underlying mechanisms of the action of 12-LOX and tumour treatment strategies remain not fully defined. In this study, we investigated the possible roles of 12-LOX in ESCC and explored the new therapeutic target. Approximately 73% of ESCC tissues showed marked up-regulation of 12-LOX, which was associated with poor prognosis. 12-LOX overexpression was positively correlated with the malignant progression of ESCC as demonstrated both in vitro and in vivo. Up-regulation of 12-LOX significantly increased the proliferation of ESCC cells and the xenograft volume. Moreover, 12-LOX up-regulation promoted tube formation of HUVECs and tumour angiogenesis in xenografts. Mechanism investigation indicated that 12-LOX overexpression led to activation of the PI3K/AKT/mTOR pathway and the up-regulation of VEGF in ESCC cells. Subsequent analysis indicated that the RAD001 could reverse the 12-LOX-induced promoting effect on ESCC. Specifically, the application of RAD001 inhibited the proliferation of ESCC cells and the tube-forming ability of HUVECs. In the drug group, the xenografts exhibited significant volume reduction and angiogenesis inhibition. We demonstrated that RAD001 could inhibit HUVEC migration. These findings presented the evidence that RAD001 had distinct roles on HUVECs and could exert anti-tumour effects by targeting not only the PI3K/AKT/mTOR pathway but the angiogenesis in ESCC.

Syntaphilin downregulation facilitates radioresistance via mediating mitochondria distribution in esophageal squamous cell carcinoma.

Syntaphilin (SNPH) halts mitochondrial movements and regulates proliferation-motility phenotype switching of cancer cells. We sought to investigate the significance of SNPH-mediated mitochondria distribution in radioresistant (RR) phenotype switching in esophageal squamous cell carcinoma (ESCC). RR ESCC cells were established by long-term exposure to radiation. Effects of SNPH on proliferation, migration, mitochondrial distribution, radiation-induced oxidative damage and radiosensitivity were investigated by overexpressing or silencing SNPH. The mechanisms regulating SNPH expression and the potential molecules mediating the SNPH-re-expression-induced radiosensitization were explored. SNPH expression in specimens from 156 patients was analyzed to evaluate its clinical significance. We found that RR ESCC cells had a sparse mitochondrial network and lower SNPH level. SNPH reconstitution in RR ESCC cells inhibited migration, induced proliferation and mitochondrial aggregation, exacerbated the radiation-induced oxidative damage and ultimately promoted radiosensitization. Mechanistically, ubiquitin-proteasomal degradation and histone modification contributed to SNPH downregulation in RR ESCC cells. Subsequently, we found that CREB dephosphorylation facilitated the SNPH re-expression-induced radiosensitization. Furthermore, SNPH expression was correlated with the radiotherapeutic efficacy and served as an independent prognostic factor for survival of ESCC patients. Our study revealed that low SNPH expression was a novel indicator for radioresistance, and targeting SNPH could be a promising regimen to improve the radiotherapeutic efficiency in ESCC patients.

KIF4A enhanced cell proliferation and migration via Hippo signaling and predicted a poor prognosis in esophageal squamous cell carcinoma.

BACKGROUND: In this study, we aimed to explore and clarify the function of KIF4A in esophageal squamous cell carcinoma (ESCC). METHODS: The microarray data were extracted from the Gene Expression Omnibus (GEO) database. We then used the database for Annotation, Visualization, and Integrated Discovery (DAVID) to perform the gene ontology function (GO) and KEGG Orthology-Based Annotation System (KOBAS) to perform Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis of differentially expressed genes (DEGs). The six core candidate genes were identified using protein-protein interaction (PPI) network analysis and Cytoscape software. Among them, the expression of KIF4A were validated by UALCAN database from the Cancer Genome Atlas (TCGA) (P < 0.05). Western blotting, qRT-PCR and IHC were used to detect the expression of KIF4A in tissues. Cell experiments (transwell migration assays, wound healing assay, CCK8 assay, and clone formation experiment) were utilized to verify the roles of KIF4A on the ESCC cells. Western blotting was used to explore the mechanism of KIF4A in ESCC. RESULTS: The expression level of KIF4A was upregulated in ESCC samples compared to those in paracancerous tissues. Transwell migration and wound healing assay showed overexpression of KIF4A significantly promoted the migration of ESCC cells. CCK8 assay and clone formation experiment analysis showed that overexpression of KIF4A promoted proliferation of ESCC cells. Western blot detection found that KIF4A could affect the phosphorylation level of Hippo signaling pathway related proteins. CONCLUSIONS: In summary, KIF4A promotes ESCC cell proliferation and migration by regulating the biological function of ESCC cells through the Hippo signaling pathway. KEY POINTS: SIGNIFICANT FINDINGS OF THE STUDY: We found that high KIF4A expression was associated with poor overall survival in esophageal squamous cell carcinoma. KIF4A expression also promoted the proliferation and migration of ESCC cells in vitro. WHAT THIS STUDY ADDS: Our experimental results explain the role of KIF4A in ESCC, and provide a new biomolecular target for the treatment of ESCC.

Fluorescent labeling and characterization of dicarboxylic cellulose nanocrystals prepared by sequential periodate-chlorite oxidation.

High-performance fluorescent composites are key to the development and improvement of fluorescent molecular probe technology. In this study, cellulose nanocrystals (CNC) with high carboxyl concentrations were prepared via sequential periodate-chlorite oxidation. Then, fluorescent cellulose nanocrystals (FCNC) were prepared by attaching 7-amino-4-methylcoumarin (AMC) onto CNC under 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride (DMTMM) catalysis. The morphology and fluorescence properties of FCNC were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, transmission electron microscopy, elemental analysis, ultraviolet-visible absorbance, fluorescence spectrophotometry, and fluorescence spectroscopy. The results showed that AMC was grafted onto the CNC surface by an amidation reaction, and the absorption and emission maxima for FCNC were blue-shifted from 350 nm and 445 nm of AMC to 335 nm and 440 nm, respectively. FCNC retained the crystallinity and nano-topography size of the CNC. The fluorescence intensity, quantum yield, and fluorescence lifetime of FCNC showed the same change law; it first increased and then decreased with an increase in the graft density of AMC from 0.201 to 0.453 AMC molecules per nm2. The FCNC prepared in this study have good optical properties and can be used in the fields of fluorescent molecular probes and biological imaging.

Pulmonary toxicity and RNA sequencing analyses of mouse in response to exposure to cellulose nanofibrils.

OBJECTIVE: The growing applications of nanocelluloses in the fields of advanced nanocomposites, electronics, and medical devices necessitate investigation of their potential adverse effects on human health. The lungs are the primary and the most important route for the entry of nanocelluloses into the human body in occupational settings. However, data on the pulmonary toxicity of cellulose nanofibrils (CNFs) and its molecular mechanism are limited. This study investigated the pulmonary toxicity of CNFs and its genomic expression using the RNA sequencing approach. MATERIALS AND METHODS: Female C57BL/6 mice were administered CNFs at 50 µg/mouse by oropharyngeal aspiration. Samples were collected at 3 and 14 days after exposure to CNFs (DAEC). RESULTS: At three DAEC, the microscopic sections of lungs revealed a significant inflammatory response. In terms of gene expression alterations, 94 genes were up-regulated, and 107 genes were down-regulated. Most of these differentially expressed genes were involved in the inflammatory and immune responses, including chemokines, NK cells, killer cell lectin-like receptors, CD antigens, T cell-specific GTPases, immunity-related GTPase family M members, and interferon-induced proteins encoding genes. However, only 9 and 26 genes at 14 DAEC were significantly up- and down-regulated, respectively. CONCLUSIONS: The pathological analysis of lung sections and the analysis of sequencing data suggested that the homeostasis of mice lungs was restored at 14 DAEC. The findings of this study provide insights into the pulmonary toxicity, and underlying toxicological mechanisms, caused by exposure to CNFs, and are useful for the assessment of the potential toxicity of nanocelluloses.

Isocitrate dehydrogenase 2 contributes to radiation resistance of oesophageal squamous cell carcinoma via regulating mitochondrial function and ROS/pAKT signalling.

BACKGROUND: Antioxidase alleviates the accumulation of radiation-induced reactive oxygen species (ROS) and therefore has strong connections with radioresistance. Isocitrate dehydrogenase 2 (IDH2) facilitates the turnover of antioxidase, but its role in radiotherapeutic efficiency in oesophageal squamous cell carcinoma (ESCC) still remains elusive. METHODS: The involvement of IDH2 in radiotherapeutic efficacy in ESCC was investigated in vitro and vivo by IDH2 knockdown. IDH2 expression in biopsy specimens of 141 patients was identified to evaluate its clinical significance. RESULTS: We found that Kyse510 and Kyse140 cells were more radioresistant and had higher IDH2 expression. In these two cell lines, IDH2 knockdown intensified the radiation-induced ROS overload and oxidative damage on lipid, protein, and nucleic acids. In addition, IDH2 silencing aggravated the radiation-induced mitochondrial dysfunction and cell apoptosis and ultimately promoted radiosensitisation via inhibiting AKT phosphorylation in a ROS-dependent manner. Furthermore, IDH2 depletion facilitated the radiation-induced growth inhibition and cell apoptosis in murine xenografts. Finally, IDH2 expression was correlated with definite chemoradiotherapy (dCRT) efficacy and served as an independent prognostic factor for survival of ESCC patients. CONCLUSIONS: IDH2 plays a key role in the radioresistance of ESCC. Targeting IDH2 could be a promising regimen to improve radiotherapeutic efficiency in ESCC patients.