CircPUM1 Knockdown Confers Radiosensitivity in Oral Squamous Cell Carcinoma by Regulating the miR-580/STAT3 Pathway.

Background: CircPUM1 acts as an oncogene in a variety of tumors, and there is no related research on oral squamous cell carcinoma. This study aimed to evaluate the clinical significance of CircPUM1 in oral squamous cell carcinoma radiotherapy. Methods: Radio-resistant cell lines were established by increasing the X-ray dose. Analysis of CircPUM1 expression in oral squamous cell carcinoma was carried out using bioinformatics tools. Cell proliferation was analyzed with CCK-8 and colony formation. Protein and gene expressions were detected by Western blotting and qPCR. RNA interference inhibits endogenous gene expression. A luciferase reporter system and immunoprecipitation were used to validate the target of CircPUM1. Result: CircPUM1 was highly expressed in OSCC. The higher the expression level of CircPUM1 in OSCC, the worse the clinical features and prognosis. Knockdown of CircPUM1 enhances the sensitivity of OSCC cells to X-rays, and expression of exogenous CircPUM1 makes OSCC cells acquire radiation resistance. The absence of CircPUM1 blocked the cells in the G0/G1 phase and triggered apoptosis. The prediction of mir-580-binding site, luciferase reporter system, and immunoprecipitation confirmed that mir-580 is the binding site of CircPUM1. In addition, STAT3 was predicted and confirmed as the binding site of mir-580. Overexpression of STAT3 partially attenuated the radiosensitivity of OSCC cells to knockdown of CircPUM1. Conclusion: CircPUM1 has the oncogene expression profile in oral squamous cell carcinoma; patients with high expression of CircPUM1 have less benefit from radiotherapy and need more frequent follow-up. In addition, CircPUM1 may be a potential therapeutic target for oral squamous cell carcinoma. The CircPUM1/mir-580/STAT3 axis has a certain effect on the radiosensitivity of OSCC. These results suggest that patients with low expression of CircPUM1 may gain more benefits.

The pursuit of a scalable nanofabrication platform for use in material and life science applications.

In this Account, we describe the use of perfluoropolyether (PFPE)-based materials that are able to accurately mold and replicate micro- and nanosized features using traditional techniques such as embossing as well as new techniques that we developed to exploit the exceptional surface characteristics of fluorinated substrates. Because of the unique partial wetting and nonwetting characteristics of PFPEs, we were able to go beyond the usual molding and imprint lithography approaches and have created a technique called PRINT (Particle [or Pattern] Replication In Nonwetting Templates). PRINT is a distinctive "top-down" fabrication technique capable of generating isolated particles, arrays of particles, and arrays of patterned features for a plethora of applications in both nanomedicine and materials science. A particular strength of the PRINT technology is the high-resolution molding of well-defined particles with precise control over size, shape, deformability, and surface chemistry. The level of replication obtained showcases some of the unique characteristics of PFPE molding materials. In particular, these materials arise from very low surface energy precursors with positive spreading coefficients, can be photocured at ambient temperature, and are minimally adhesive, nonswelling, and conformable. These distinctive features enable the molding of materials with unique attributes and nanometer resolution that have unprecedented scientific and technological value. For example, in nanomedicine, the use of PFPE materials with the PRINT technique allows us to design particles in which we can tailor key therapeutic parameters such as bioavailability, biodistribution, target-specific cell penetration, and controlled cargo release. Similarly, in materials science, we can fabricate optical films and lens arrays, replicate complex, naturally occurring objects such as adenovirus particles, and create 2D patterned arrays of inorganic oxides.

The Patterning of Sub-500 nm Inorganic Oxide Structures.

Elastomeric perfluoropolyether molds are applied to pattern arrays of sub-500 nm inorganic oxide features. This versatile soft-lithography technique can be used to pattern a wide range of materials; in this work inorganic oxides including TiO2 , SnO2 , ZnO, ITO, and BaTiO3 are patterned on a variety of substrates with different aspect ratios. An example of TiO2 posts is shown in the figure.

Superhydrophobic behavior of a perfluoropolyether lotus-leaf-like topography.

We demonstrate the fabrication of 2-D arrays of nanopillars made from perfluoropolyether derivatives using a porous anodic aluminum oxide membrane as a template. Pretexturing the aluminum prior to anodization enables one to engineer multiple morphological length scales and thereby synthesize a lotus-leaf-like topography. Both nanopillars on a flat surface and on a lotus-leaf-like topology exhibit superhydrophobicity, low contact angle hysteresis, and self-cleaning.

Molded, high surface area polymer electrolyte membranes from cured liquid precursors.

Polymer electrolyte membranes (PEMs) for fuel cells have been synthesized from easily processable, 100% curable, low molecular weight reactive liquid precursors that are photochemically cured into highly proton conductive solid membranes. The liquid precursors were directly cured into membranes of desired dimensions without the need for further processing steps such as melt extrusion or solvent casting. By employing chemical cross-linking, high proton conductivities can be achieved through the incorporation of significant levels of acidic groups without rendering the material water-soluble, which plagues commonly used non-cross-linked polymers. Fabrication of membrane electrode assemblies (MEAs) from these PEMs resulted in fuel cells that outperformed those based on commercial materials. Moreover, these liquid precursors enabled the formation of three-dimensional, patterned PEMs with high fidelity, micron-scale features by using soft lithographic/micromolding techniques. The patterned membranes provided a larger interfacial area between the membrane and catalyst layer than standard flat PEMs. MEAs composed of the patterned membranes demonstrated higher power densities over that of flat ones without an increase in the macroscopic area of the fuel cells. This can potentially miniaturize fuel cells and promote their application in portable devices.

Micellar shape change and internal segregation induced by chemical modification of a tryptych block copolymer surfactant.

We report the detailed characterization of micelles formed by two nonionic, amphiphilic ABC triblock copolymers. Poly(ethylene oxide)-b-poly(styrene)-b-1,2-poly(butadiene) (PEO-b-PS-b-PB) triblock copolymer "OSB" forms core-corona spherical micelles in aqueous solution, and the two hydrophobic blocks S and B are mixed homogeneously within the micelle core. PEO-b-PS-b-PB:C6F13I triblock copolymer "OSF" was prepared by selective fluorination of the B block in OSB with n-perfluorohexyl iodide. Fluorination of the B block induces internal segregation into an inner F core and an intermediate S shell. Furthermore, the strong incompatibility that results from fluorination drives a shape change into an oblate ellipsoid. These micellar morphologies are confirmed by combined light, neutron, and X-ray scattering measurements, as well as TEM imaging.