Ningning Wang

BACKGROUND: Accumulating evidences indicate that non-coding RNAs (ncRNAs) including long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) acting as crucial regulators in osteosarcoma (OS). Previously, we reported that Rho associated coiled-coil containing protein kinase 1 (ROCK1), a metastatic-related gene was negatively regulated by microRNA-335-5p (miR-335-5p) and work as an oncogene in osteosarcoma. Whether any long non-coding RNAs participate in the upstream of miR-335-5p/ROCK1 axial remains unclear. METHODS: Expression of differentiation antagonizing non-protein coding RNA (DANCR) and miR-335-5p/miR-1972 in osteosarcoma tissues were determined by a qRT-PCR assay and an ISH assay. Osteosarcoma cells' proliferation and migration/invasion ability changes were measured by a CCK-8/EDU assay and a transwell assay respectively. ROCK1 expression changes were checked by a qRT-PCR assay and a western blot assay. Targeted binding effects between miR-335-5p/miR-1972 and ROCK1 or DANCR were verified by a dual luciferase reporter assay and a RIP assay. In vivo experiments including a nude formation assay as well as a CT scan were applied to detect tumor growth and metastasis changes in animal level. RESULTS: In the present study, an elevated DNACR was found in osteosarcoma tissue specimens and in osteosarcoma cell lines, and the elevated DNACR was closely correlated with poor prognosis in clinical patients. Functional experiments illustrated that a depression of DANCR suppressed ROCK1-mediated proliferation and metastasis in osteosarcoma cells. The results of western blot assays and qRT-PCR assays revealed that DANCR regulated ROCK1 via crosstalk with miR-335-5p and miR-1972. Further cellular behavioral experiments demonstrated that DNACR promoted ROCK1-meidated proliferation and metastasis through decoying both miR-335-5p and miR-1972. Finally, the outcomes of in vivo animal models showed that DANCR promoted tumor growth and lung metastasis of osteosarcoma. CONCLUSIONS: LncRNA DANCR work as an oncogene and promoted ROCK1-mediated proliferation and metastasis through acting as a competing endogenous RNA (ceRNA) in osteosarcoma.

Endothelial cell (EC) proliferation and migration are important for reendothelialization and angiogenesis. We have demonstrated that reactive oxygen species (ROS) derived from the small GTPase Rac1-dependent NAD(P)H oxidase are involved in vascular endothelial growth factor (VEGF)-mediated endothelial responses mainly through the VEGF type2 receptor (VEGFR2). Little is known about the underlying molecular mechanisms. IQGAP1 is a scaffolding protein that controls cellular motility and morphogenesis by interacting directly with cytoskeletal, cell adhesion, and small G proteins, including Rac1. In this study, we show that IQGAP1 is robustly expressed in ECs and binds to the VEGFR2. A pulldown assay using purified proteins demonstrates that IQGAP1 directly interacts with active VEGFR2. In cultured ECs, VEGF stimulation rapidly promotes recruitment of Rac1 to IQGAP1, which inducibly binds to VEGFR2 and which, in turn, is associated with tyrosine phosphorylation of IQGAP1. Endogenous IQGAP1 knockdown by siRNA shows that IQGAP1 is involved in VEGF-stimulated ROS production, Akt phosphorylation, endothelial migration, and proliferation. Wound assays reveal that IQGAP1 and phosphorylated VEGFR2 accumulate and colocalize at the leading edge in actively migrating ECs. Moreover, we found that IQGAP1 expression is dramatically increased in the VEGFR2-positive regenerating EC layer in balloon-injured rat carotid artery. These results suggest that IQGAP1 functions as a VEGFR2-associated scaffold protein to organize ROS-dependent VEGF signaling, thereby promoting EC migration and proliferation, which may contribute to repair and maintenance of the functional integrity of established blood vessels.

The control of charge transfer between radical anions and cations is a promising way for decoding the emission mechanism in electrochemiluminescence (ECL) systems. Herein, a type of donor-acceptor (D-A) covalent organic framework (COF) with triphenylamine and triazine units is designed as a highly efficient ECL emitter with tunable intrareticular charge transfer (IRCT). The D-A COF demonstrates 123 folds enhancement in ECL intensity compared with its benzene-based COF with small D-A contrast. Further, the COF's crystallinity- and protonation-modulated ECL behaviors confirm ECL dependence on intrareticular charge transfer between donor and acceptor units, which is rationalized by density functional theory. Significantly, dual-peaked ECL patterns of COFs are achieved through an IRCT mediated competitive oxidation mechanism: the coreactant-mediated oxidation at lower potential and the direct oxidation at higher potential. This work provides a new fundamental and approach to improve the ECL efficiency for designing next-generation ECL devices.

This work presents a mixed-ligand metal–organic framework (m-MOF) integrated with two ligands, one as a luminophore and the other as a coreactant, on one metal node for self-enhanced electrochemiluminescence (ECL). Both 9,10-di(p-carboxyphenyl)anthracene (DPA) and 1,4-diazabicyclo[2.2.2]octane (D-H2) ligands can be oxidized, generating the cation radicals DPA+• and D-H2+•, respectively. The latter can be deprotonated to form the neutral radical (D-H•) and then react with DPA+• to produce excited DPA* for ECL emission without exogenous coreactants. As a result of the incorporation into the MOF framework and the intrareticular charge transfer between the two ligands, the ECL intensity of the m-MOF was increased 26.5-fold compared with that of the mixture of DPA and D-H2 in aqueous solution. Moreover, with the process of second oxidation of D-H2, stepwise ECL emission was observed as a result of local excitation in the DPA unit, which was identified through density functional theory calculations. Overall, the implementation of the mixed-ligand approach, which combines the luminophore and coreactant as linkers in reticular materials, enriches the fundamentals and applications of ECL systems.

Metal-organic frameworks (MOFs) have limited applications in electrochemistry owing to their poor conductivity. Now, an electroactive MOF (E-MOF) is designed as a highly crystallized electrochemiluminescence (ECL) emitter in aqueous medium. The E-MOF contains mixed ligands of hydroquinone and phenanthroline as oxidative and reductive couples, respectively. E-MOFs demonstrate excellent performance with surface state model in both co-reactant and annihilation ECL in aqueous medium. Compared with the individual components, E-MOFs significantly improve the ECL emission due to the framework structure. The self-enhanced ECL emission with high stability is realized by the accumulation of MOF cation radicals via pre-reduction electrolysis. The self-enhanced mechanism is theoretically identified by DFT. The mixed-ligand E-MOFs provide a proof of concept using molecular crystalline materials as new ECL emitters for fundamental mechanism studies.