SHCBP1 promotes cisplatin resistance of ovarian cancer through AKT/mTOR/Autophagy pathway.

Ovarian cancer caused the highest cancer-related mortality among female reproductive system malignancies. Platinum-based chemotherapy is still the footstone of the chemotherapy for ovarian cancer. However, the molecular mechanisms underlying cisplatin insensitivity and resistance remain unclear. SHC SH2 domain-binding protein 1 (SHCBP1) plays critical roles in the progression and drug resistance of different types of cancer. However, the biological function of SHCBP1 in ovarian cancer progression and cisplatin resistance remains obscure. In this study, we found that SHCBP1 was upregulated in ovarian cancer and the upregulated SHCBP1 has growth-promoting effect on ovarian cancer cells. Furthermore, SHCBP1 silencing sensitize ovarian cancer cells to cisplatin (hereafter referred to as CDDP). Mechanism analysis revealed that SHCBP1 activated the Akt/mTOR pathway and further inhibited autophagy in ovarian cancer cells. Meanwhile, autophagy inhibitors combined with SHCBP1 knockdown enhances CDDP sensitivity. In addition, knockdown of SHCBP1 restricted the proliferation of tumors and increased the cisplatin sensitivity in vivo. These findings suggested that upregulated SHCBP1 promoted the proliferation and CDDP resistance of ovarian cancer. The combination of SHCBP1 inhibition and cisplatin treatment might lead to substantial progress in ovarian cancer targeted therapy.

A20 ameliorates Aspergillus fumigatus keratitis by promoting autophagy and inhibiting NF-κB signaling.

Fungal keratitis (FK) is a serious, potentially sight-threatening corneal infection, which is associated with poor prognosis. A20, also called TNFAIP3, plays significant roles in the negative regulation of inflammation and immunity. However, the function of A20 in Aspergillus fumigatus (A. fumigatus) keratitis remains obscure. Herein, we found that the level of A20 is increased in human corneal epithelial cells (HCECs) and in mouse corneas with A. fumigatus infection, and that nuclear factor-κB (NF-κB) signaling is required for A20 upregulation. A20 overexpression inhibits A. fumigatus-mediated inflammatory responses, while A20 knockdown results in opposite effect. Mechanically, we showed that A20 inhibits NF-κB signaling and activates autophagy in infected HCECs. We also showed that inhibition of NF-κB signaling reverses the increased inflammatory responses in infected HCECs with A20 knockdown. Furthermore, autophagy blockage impedes the anti-inflammatory effect of A20 in A. fumigatus infected HCECs. Moreover, A20 ameliorates the corneal damage and inflammation in A. fumigatus infected mouse corneas. In conclusion, this study reveals that A20 alleviates A. fumigatus keratitis by activating autophagy and inhibiting NF-κB signaling. This suggests that exogenous use of A20 protein may be a potentially promising therapeutic strategy for FK treatment.

HMGB3 promotes the malignant phenotypes and stemness of epithelial ovarian cancer through the MAPK/ERK signaling pathway.

BACKGROUND: Ovarian cancer, particularly epithelial ovarian cancer (EOC), is the leading cause of cancer-related mortality among women. Our previous study revealed that high HMGB3 levels are associated with poor prognosis and lymph node metastasis in patients with high-grade serous ovarian carcinoma; however, the role of HMGB3 in EOC proliferation and metastasis remains unknown. METHODS: MTT, clonogenic, and EdU assays were used to assess cell proliferation. Transwell assays were performed to detect cell migration and invasion. Signaling pathways involved in HMGB3 function were identified by RNA sequencing (RNA-seq). MAPK/ERK signaling pathway protein levels were evaluated by western blot. RESULTS: HMGB3 knockdown inhibited ovarian cancer cell proliferation and metastasis, whereas HMGB3 overexpression facilitated these processes. RNA-seq showed that HMGB3 participates in regulating stem cell pluripotency and the MAPK signaling pathway. We further proved that HMGB3 promotes ovarian cancer stemness, proliferation, and metastasis through activating the MAPK/ERK signaling pathway. In addition, we demonstrated that HMGB3 promotes tumor growth in a xenograft model via MAPK/ERK signaling. CONCLUSIONS: HMGB3 promotes ovarian cancer malignant phenotypes and stemness through the MAPK/ERK signaling pathway. Targeting HMGB3 is a promising strategy for ovarian cancer treatment that may improve the prognosis of women with this disease. Video Abstract.

MCPIP1 alleviates inflammatory response through inducing autophagy in Aspergillus fumigatus keratitis.

Fungal keratitis (FK) is a serious corneal infection caused by pathogenic fungi. Monocyte chemoattractant protein-induced protein 1 (MCPIP1) plays an important role in restricting the inflammatory response in various immune disorders. However, the function of MCPIP1 in Aspergillus fumigatus (A. fumigatus) keratitis is unclear. In the present study, we found that A. fumigatus infection promotes the expression of MCPIP1 in human corneal epithelial cells (HCECs) and in mouse corneas. Overexpression of MCPIP1 decreased the production of inflammatory cytokines, including TNF-α, IL-6, and IL-1ß, while knockdown of MCPIP1 increased the expression of these cytokines. MCPIP1 enhanced autophagy flux by inhibiting the mTOR signaling in HCECs with A. fumigatus infection. Further study showed that inhibition of autophagy using chloroquine reverses the anti-inflammatory effect of MCPIP1 in HCECs infected with A. fumigatus. Moreover, MCPIP1 alleviated the severity of keratitis and inhibited the expression of inflammatory cytokines by activating autophagy in an FK mouse model. In conclusion, our study demonstrated that MCPIP1 alleviates the severity of A. fumigatus keratitis by inducing mTOR-mediated autophagy in HCECs and in a mouse model. Exogenous use of MCPIP1 protein may have potential applications in FK clinical therapy.

Design of Faster R-CNN-Based Fault Detection Method for Subway Vehicles.

A substantial amount of maintenance and fault data is not properly utilized in the daily maintenance of pantographs in urban metro cars. Pantograph fault analysis can begin with three factors: the external environment, internal flaws, and joint behavior. Based on the analysis of pantograph fault types, corresponding measures are proposed in terms of pantograph fault handling and maintenance strategies, in order to provide safety guarantee for the safe and effective realization of rail transit vehicle speed-up and also provide reference for the maintenance and overhaul of pantographs. For the problem of planned maintenance no longer meeting current pantograph maintenance requirements, a defect diagnosis system based on a combination of faster R-CNN neural networks is presented. The pantograph image features are extracted by introducing an alternative to the original feature extraction module that can extract deep-level image features and achieve feature reuse, and the data transformation operations such as image rotation and enhancement are used to expand the sample set in the experiment to enhance the detection effect. The simulation results demonstrate that the diagnosis procedure is quick and accurate.

PBK drives PARP inhibitor resistance through the TRIM37/NFκB axis in ovarian cancer.

Resistance to PARP inhibitors (PARPi) remains a therapeutic challenge in ovarian cancer patients. PDZ-binding kinase (PBK) participates in the chemoresistance of many malignancies. However, the role of PBK in PARPi resistance of ovarian cancer is obscure. In the current study, we demonstrated that overexpression of PBK contributed to olaparib resistance in ovarian cancer cells. Knockdown of PBK sensitized olaparib-resistant SKOV3 cells to olaparib. Inhibition of PBK using a specific inhibitor enhanced the therapeutic efficiency of olaparib. Mechanically, PBK directly interacted with TRIM37 to promote its phosphorylation and nuclear translocation. which subsequently activates the NFκB pathway. Additionally, PBK enhanced olaparib resistance of ovarian cancer by regulating the NFκB/TRIM37 axis in vitro and in vivo. In conclusion, PBK confers ovarian cancer resistance to PARPi through activating the TRIM37-mediated NFκB pathway, and targeted inhibition of PBK provided the new therapy to improve PARPi treatment outcomes for ovarian cancer patients.

HMGB3 promotes PARP inhibitor resistance through interacting with PARP1 in ovarian cancer.

Poly (ADP-ribose) polymerase (PARP) inhibitor (PARPi) resistance remains a therapeutic challenge in ovarian cancer. High-mobility group box 3 (HMGB3) plays significant roles in the development of drug resistance of many cancers. However, the function of HMGB3 in PARPi resistance is poorly understood. In the current study, we clarified that HMGB3 was aberrantly overexpressed in high-grade serous ovarian carcinoma (HGSOC) tissues, and high HMGB3 levels indicated shorter overall survival and drug resistance in HGSOC. The overexpression of HMGB3 increased the insensitivity of ovarian cancer to PARPi, whereas HMGB3 knockdown reduced PARPi resistance. Mechanistically, PARP1 was identified as a novel interaction partner of HMGB3, which could be blocked using olaparib and was enhanced upon DNA damage conditions. We further showed that loss of HMGB3 induced PARP1 trapping at DNA lesions and inhibited the PARylation activity of PARP1, resulting in an increased DNA damage response and cell apoptosis. The PARPi-resistant role of HMGB3 was also verified in a xenograft mouse model. In conclusion, HMGB3 promoted PARPi resistance via interacting with PARP1, and the targeted inhibition of HMGB3 might overcome PARPi resistance in ovarian cancer therapy.

TTK inhibition increases cisplatin sensitivity in high-grade serous ovarian carcinoma through the mTOR/autophagy pathway.

High-grade serous ovarian cancer (HGSOC) is the most lethal gynecological malignancy. However, the molecular mechanisms underlying HGSOC development, progression, chemotherapy insensitivity and resistance remain unclear. Two independent GEO datasets, including the gene expression profile of primary ovarian carcinoma and normal controls, were analyzed to identify genes related to HGSOC development and progression. A KEGG pathway analysis of the differentially expressed genes (DEGs) revealed that the cell cycle pathway was the most enriched pathway, among which TTK protein kinase (TTK) was the only gene with a clinical-grade inhibitor that has been investigated in a clinical trial but had not been studied in HGSOC. TTK was also upregulated in cisplatin-resistant ovarian cancer cells from two other datasets. TTK is a regulator of spindle assembly checkpoint signaling, playing an important role in cell cycle control and tumorigenesis in various cancers. However, the function and regulatory mechanism of TTK in HGSOC remain to be determined. In this study, we observed TTK upregulation in patients with HGSOC. High TTK expression was related to a poor prognosis. Genetic and pharmacological inhibition of TTK impeded the proliferation of ovarian cancer cells by disturbing cell cycle progression and increasing apoptosis. TTK silencing increased cisplatin sensitivity by activating the mammalian target of rapamycin (mTOR) complex to further suppress cisplatin-induced autophagy in vitro. In addition, the enhanced sensitivity was partially diminished by rapamycin-mediated inhibition of mTOR in TTK knockdown cells. Furthermore, TTK knockdown increased the toxicity of cisplatin in vivo by decreasing autophagy. These findings suggest that the administration of TTK inhibitors in combination with cisplatin may lead to improved response rates to cisplatin in patients with HGSOC presenting high TTK expression. In summary, our study may provide a theoretical foundation for using the combination therapy of cisplatin and TTK inhibitors as a treatment for HGSOC in the future.

ALOX5AP Predicts Poor Prognosis by Enhancing M2 Macrophages Polarization and Immunosuppression in Serous Ovarian Cancer Microenvironment.

BACKGROUND: Serous ovarian cancer (SOC) is a highly lethal gynecological malignancy with poor prognosis. Given the importance of the immune-related tumor microenvironment (TME) in ovarian cancer, investigating tumor-immune interactions and identifying novel prognostic and therapeutic targets in SOC is a promising avenue of research. ALOX5AP (Arachidonate 5-Lipoxygenase Activating Protein) is a key enzyme in converting arachidonic acid to leukotriene: a crucial immune-modulating lipid mediator. However, the role of ALOX5AP in SOC has yet to be studied. METHODS: ALOX5AP expression patterns across ovarian cancer and their normal tissue counterparts were cross-checked using public microarray and RNA-seq analyses and then validated in clinical samples by qRT-PCR. Kaplan-Meier survival analysis was performed in multiple independent SOC patient cohorts. Univariate and multivariate Cox regression analysis were then employed to identify clinical risk parameters associated with survival, and a genomic-clinicopathologic nomogram was built. Gene enrichment, immune infiltration, and immunosuppressor correlation analyses were then evaluated. RESULTS: ALOX5AP mRNA levels in SOC tissues were significantly upregulated compared to normal tissues. Elevated ALOX5AP was markedly associated with poor overall survival and progression-free survival in multiple SOC patient cohorts as well as with adverse clinicopathological features, including lymphatic invasion, unsatisfactory cytoreductive surgery, rapid relapse after primary treatment, and platinum non-responsiveness. A predictive nomogram, which integrated ALOX5AP expression and two independent prognosis factors (primary therapy outcome and tumor residual), was conducted to predict the 3-year and 5-year survival rate of SOC patients. Mechanistically, functional and pathway enrichment analyses revealed that ALOX5AP was primarily involved in immune response and regulation. Further exploration demonstrated that ALOX5AP was highly expressed in the immunoreactive subtype of ovarian cancer and closely related to immunocyte infiltration, especially M2 macrophage polarization. Additionally, ALOX5AP was enriched in the C4 (lymphocyte depleted) immune subtype of SOC and associated with crucial immune-repressive receptors in the tumor microenvironment at the genomic level. CONCLUSIONS: ALOX5AP expression indicates a worse survival outcome and has the potential to be utilized as a prognostic predictor for SOC patients. Given the availability of well-studied ALOX5AP inhibitors, this study has immediate clinical implications for the exploitation of ALOX5AP as an immunotherapeutic target in SOC.

CDCA8, targeted by MYBL2, promotes malignant progression and olaparib insensitivity in ovarian cancer.

Ovarian cancer is the most lethal gynecologic malignancy. Poly (ADP-ribose) polymerase inhibitors (PARPi) are effective in treating ovarian cancer. However, cancer cell insensitivity and resistance remain challenges. Determination of the exact chemoresistance mechanisms and potential targeted therapies is urgent. CDCA8 (cell division cycle associated 8) participates in the tumorigenesis of various cancers; however, the exact biological function of CDCA8 in ovarian cancer remains obscure. Here, we found that CDCA8 was overexpressed in ovarian cancer and that high expression of CDCA8 promoted the proliferation of ovarian cancer cells in vitro and in vivo. Moreover, silencing of CDCA8 sensitized ovarian cancer cells to olaparib and cisplatin by inducing G2/M arrest, accelerating apoptosis, increasing DNA damage and interfering with RAD51 accumulation in vitro. In addition, MYBL2 (MYB proto-oncogene-like 2), identified as an upstream transcription factor of CDCA8, was positively correlated with the expression level of CDCA8 in ovarian cancer. Finally, MYBL2 enhanced the aggressive characteristics of ovarian cancer cells by regulating CDCA8. In conclusion, high CDCA8 expression was involved in the tumorigenesis, aggressiveness and chemoresistance of ovarian cancer. CDCA8 silencing combined with olaparib treatment might lead to substantial progress in ovarian cancer targeted therapy.

PBK promotes aggressive phenotypes of cervical cancer through ERK/c-Myc signaling pathway.

Cervical cancer is the fourth most frequent cancer in women worldwide. PDZ-binding kinase (PBK) is proven to promote the malignant behaviors of various carcinomas. However, its functional roles and oncogenic mechanisms in cervical cancer are poorly understood. In this study, we reported that PBK was highly expressed in cervical cancer tissues. PBK promoted the proliferation, metastasis, and cisplatin resistance of cervical cancer cells. OTS514, a specific PBK inhibitor, could significantly suppress proliferation and metastasis of cervical cancer cells in vitro and in a xenograft model. Besides, OTS514 could enhance cisplatin-based chemosensitivity in cervical cancer cells. Mechanistically, PBK promoted the expression and stabilization of c-Myc through phosphorylating ERK1/2. OTS514 suppressed the phosphorylation of ERK1/2 and the transcriptional activity of c-Myc. Furthermore, inhibition of the ERK signal pathway by U0126 reversed the increased proliferation and metastasis induced by overexpression of PBK. Exogenous expression of c-Myc counteracted the decreased proliferation and metastasis evoked by knockdown of PBK. In conclusion, PBK promoted the malignant progression of cervical cancer through ERK/c-Myc signal pathway. PBK might be a promising molecular target for cervical cancer treatment.

RECQL4, Negatively Regulated by miR-10a-5p, Facilitates Cell Proliferation and Invasion via MAFB in Ovarian Cancer.

The high frequency of somatic copy number alterations, as opposed to point mutations, is considered a unique feature of ovarian cancer. Amplification-dependent overexpression of RecQ protein-like 4 (RECQL4), which participates in DNA replication and repair, mediates the development of various cancers, but its pathobiological and clinical roles are poorly understood. Here, using bioinformatics analysis, RECQL4 amplification was found to occur in 27% of ovarian cancer samples in the TCGA cohort. RECQL4 was found to be upregulated and associated with a poor prognosis based on the immunohistochemistry staining of ovarian cancer. Functionally, RECQL4 overexpression increased proliferation and invasion of ovarian cancer cells. RECQL4 silencing had the opposite effects. In addition, RECQL4 knockdown enhanced the sensitivity of ovarian cancer cells to cisplatin and PARP inhibitor (PARPi). Further mechanistic investigations revealed that MAFB was a downstream target of RECQL4. The oncogenic effect of RECQL4 was attenuated after MAFB knockdown. Moreover, RECQL4 overexpression was negatively regulated by the tumor suppressor miR-10a-5p. Collectively, these findings indicate that genomic amplification and low expression of miR-10a-5p contribute to RECQL4 overexpression in ovarian cancer. This is the first study to reveal the oncogenic functions and clinical significance of RECQL4 in ovarian cancer.

FBLN5 is targeted by microRNA­27a­3p and suppresses tumorigenesis and progression in high­grade serous ovarian carcinoma.

High-grade serous ovarian carcinoma (HGSOC) is one of the most lethal gynecological malignancies; however, the precise molecular mechanisms have not been fully characterized. Fibulin­5 (FBLN­5) is an extracellular matrix (ECM) glycoprotein, and plays a crucial role in maintaining the stability of ECM structures, regulating cell proliferation and tumorigenesis. In the present study, the expression of FBLN­5, as determined by western blot analysis and immunohistochemistry, was significantly increased in normal fallopian tube (FT) samples compared with that in HGSOC samples, and decreased FBLN5 expression was associated with unfavorable prognosis of HGSOC. Functional characterization revealed that FBLN5 overexpression significantly inhibited migration, invasion and proliferation abilities of ovarian cancer cells in vitro. Furthermore, micro (mi)RNA­27a­3p (miR­27a­3p) was revealed to be increased in HGSOC, and dual­luciferase reporter assay indicated that miR­27a­3p was functioned as a negative regulator of FBLN5 by directly binding with its 3'­untranslated region. Collectively, FBLN5 expression was associated with prognosis, proliferation, and metastasis in HGSOC. We hypothesized that FBLN5 was targeted by miR­27a­3p and may serve as a biomarker and provide a new therapeutic approach for the treatment of HGSOC.

Correction to: Kallistatin inhibits tumour progression and platinum resistance in high-grade serous ovarian cancer.

The original article [1] contains errors in Fig. 3C, Results and Discussion.

Kallistatin inhibits tumour progression and platinum resistance in high-grade serous ovarian cancer.

Ovarian cancer is the most lethal gynaecologic malignancy. Although there are various subtypes of ovarian cancer, high-grade serous ovarian cancer (HGSOC) accounts for 70% of ovarian cancer deaths. Chemoresistance is the primary reason for the unfavourable prognosis of HGSOC. Kallistatin (KAL), also known as SERPINA4, is part of the serpin family. Kallistatin has been discovered to exert multiple effects on angiogenesis, inflammation and tumour progression. However, the roles and clinical significance of kallistatin in HGSOC remain unclear. Here, we showed that kallistatin was significantly downregulated in HGSOC compared to normal fallopian tube (FT) tissues. Low expression of kallistatin was associated with unfavourable prognosis and platinum resistance in HGSOC. Overexpression of kallistatin significantly inhibited proliferation and metastasis, and enhanced platinum sensitivity and apoptosis in ovarian cancer cells. Collectively, these findings demonstrate that kallistatin serves as a prognostic predictor and provide a potential therapeutic target for HGSOC.

Loss of HMBOX1 promotes LPS-induced apoptosis and inhibits LPS-induced autophagy of vascular endothelial cells in mouse.

Our previous study revealed that Homeobox containing 1 (HMBOX1), essential for the survival of vascular endothelial cells (VECs), was involved in the progression of atherosclerosis. Knockdown of HMBOX1 promoted apoptosis and inhibited autophagy through regulating intracellular free zinc level in cultured VECs. In current study, in order to investigate the roles of HMBOX1 in vivo and in endothelium, we generated a knockout (KO) mouse for HMBOX1 by using transcription activator-like effector nucleases (TALENs) technology. Herein, we reported that the protein level of HMBOX1 was gradually increased during mouse development. The HMBOX1 KO mouse was viable and fertile. There existed no differences in apoptosis and autophagy of aortic endothelial cells between wild type and KO mouse. Whereas, loss of HMBOX1 promoted apoptosis and inhibited autophagy of aortic endothelial cells under lipopolysaccharide (LPS) stimulation in mouse. We also demonstrated that HMBOX1 deletion had no influence on the secretion of inflammatory cytokines TNF-α and IL-6. Moreover, overexpression or knockdown of HMBOX1 failed to regulate multiple pro-apoptotic genes expression in vitro. In conclusion, HMBOX1 participated in the functional maintenance of mouse aortic endothelial cells, the aortic endothelial cells of HMBOX1 KO mouse showed increased apoptosis and decreased autophagy with LPS treatment.

A ratiometric fluorescence probe based on a novel recognition mechanism for monitoring endogenous hypochlorite in living cells.

A ratiometric fluorescence probe (named ZOC) for the fast detection of HClO/ClO- was constructed by coumarin (donor) and pyridinium (acceptor) based on Forster resonance energy transfer (FRET) and intramolecular charge transfer (ICT) platform. ZOC possessed red emission signal (610 nm), large Stocks shift (190 nm), high energy transfer efficiency (95.3%), high selectivity and sensitivity, low detection limit (25 nM), wider detection range (from 25 nM to 30 µM), rapid response (within 13 S), and good biocompatibility. It was very interesting that the recognition mechanism involved a new organic reaction in which olefin double bond reacted first with HClO/ClO- regioselectively, followed by cyclization. ZOC was successfully used to the real time detection of endogenous HClO/ClO- in RAW 264.7 cells.

PBK, targeted by EVI1, promotes metastasis and confers cisplatin resistance through inducing autophagy in high-grade serous ovarian carcinoma.

High-grade serous ovarian carcinoma (HGSOC) is the most lethal type of gynecologic malignancy. Chemoresistance is the main reason for the poor prognosis of HGSOC. PDZ-binding kinase (PBK) promotes the malignant progression of various carcinomas. However, the roles and clinical significance of PBK in HGSOC remain unclear. Here, we reported that PBK was overexpressed in HGSOC tissues and cell lines. High PBK expression was associated with a poor prognosis, metastasis, and cisplatin resistance of HGSOC. Overexpression of PBK promoted autophagy and enhanced cisplatin resistance via the ERK/mTOR signaling pathway. Further study showed that inhibition of autophagy by chloroquine or bafilomycin A1 reversed PBK-induced cisplatin resistance. Overexpression of PBK decreased ovarian cancer responsiveness to cisplatin treatment through inducing autophagy in vivo. We also demonstrated that the PBK inhibitor OTS514 augmented the growth inhibition effect of cisplatin in vitro and in vivo. Moreover, ecotropic viral integration site-1 (EVI1) could regulate PBK expression through directly targeting the PBK promoter region. In conclusion, high PBK expression was correlated with a poor prognosis, metastasis, and cisplatin resistance through promoting autophagy in HGSOC. PBK might be a promising target for the early diagnosis and individual treatment of ovarian cancer.

A novel lipid droplets-targeting ratiometric fluorescence probe for hypochlorous acid in living cells.

Lipid droplets were found to be involved in many organism activities. Here, a lipid droplets-targeted near-infrared fluorescence probe (named XHZ) for ratiometric detection of endogenous hypochlorous acid/hypochlorite (HClO/ClO-) in living cells was developed, which was constructed by a coumarin moiety and a malononitrile derivative. XHZ could detect HClO/ClO- with high selectivity and sensitivity in a ratiometric manner based on FRET (Förster Resonance Energy Transfer) mechanism. The two well-resolved emission (470/672 nm) bands could ensure accurate detection of HClO/ClO- in vitro as well as in vivo. XHZ was successfully used for ratiometric fluorescence imaging of exogenous and endogenous HClO/ClO- in RAW264.7 cells. A good linear relationship between the fluorescence intensity ratios of the two emissions and HClO/ClO- concentrations from 0 to 40 µM was obtained. Importantly, XHZ could localize mainly in lipid droplets of RAW264.7 cells. To the best of our knowledge, XHZ is the first lipid droplets-targeted ratiometric fluorescence probe for HClO/ClO-.

Preparation of Poly(bis(phenoxy)phosphazene) and 31P NMR Analysis of Its Structural Defects under Various Synthesis Conditions.

Poly(aryloxy)phosphazenes emerge as an important class of hybrid polymers for a whole range of potential applications. To date, however, little is known about the detailed reaction mechanisms during preparation. This draws a great deal of attention for developing well-defined and well-controllable synthesis methods. In this paper, poly(dichlorophosphazene) (PDCP) has been successfully synthesized, and subsequent reaction with sodium phenoxide or phenol in the presence of K2CO3 can produce poly(bis(phenoxy)phosphazene) (PBPP). To elucidate the issues of branching and cross-linking, focuses have been placed on the change of various reaction conditions, in terms of concentration, temperature, time, solvent, catalysis, etc. The product polymers were examined using the techniques of 31P and 13C NMR, GPC, XPS, and FT-IR, in order to characterize the structural defects, in particular, branching and unwanted substitutions, such as addition of water molecules or oxidation of the phosphorus atoms on the backbone of the polymers. This work sheds light on the tailor design of poly(aryloxy)phosphazenes and other polyphosphazenes with more uniform and controllable structures.