Lowly expressed lncRNA PVT1 suppresses proliferation and advances apoptosis of glioma cells through up-regulating microRNA-128-1-5p and inhibiting PTBP1.

BACKGROUND: Glioma is a primary intracranial malignancy with poor prognosis, of which the pathogenesis remains to be elucidated. Therein, the aim of this study is to discuss the impacts of lncRNA plasmacytoma variant translocation 1 (PVT1)/microRNA-128-1-5p (miR-128-1-5p)/polypyrimidine tract-binding protein 1 (PTBP1) axis on the biological characteristics of glioma cells. METHODS: Glioma tissue samples (72 cases) and normal brain tissue samples (35 cases) were harvested. The expression of PVT1, miR-128-1-5p and PTBP1 in glioma tissues and cells was detected. Glioma cells were transfected with sh-PVT1, miR-128-1-5p mimics or miR-128-1-5p inhibitors to verify the impacts of PVT1 and miR-128-1-5p on DNA damage, cell colony formation, invasion, proliferation, migration and apoptosis of glioma U87 and U251 cells. The growth of transplanted tumor was tested by tumor xenograft in nude mice. The combination of PVT1 and miR-128-1-5p and the targeting relationship between miR-128-1-5p and PTBP1 were verified. RESULTS: PVT1 and PTBP1 expression was enhanced and miR-128-1-5p expression was degraded in glioma tissues and cells. Overexpressed miR-128-1-5p and lowly-expressed PVT1 promoted DNA damage, suppressed colony formation, invasion, proliferation and migration as well as boosted apoptosis of U251 and U87 cells. Up-regulating miR-128-1-5p and down-regulating PVT1 reduced transplanted tumor volume and weight of glioma in mice. Low expression miR-128-1-5p reversed the effect of low expression PVT1 on the biological characteristics of glioma cells. PVT1 specifically bound to miR-128-1-5p and PTBP1 was the target gene of miR-128-1-5p. CONCLUSION: This study suggests that down-regulated PVT1 or up-regulated miR-128-1-5p boosts apoptosis and attenuates proliferation of glioma cells by inhibiting PTBP1 expression. This study is essential for finding new therapeutic targets for glioma.

Fabrication of polycrystalline tubular ZnO via a modified ultrasonically assisted two-step polyol process and characterization of the nanotubes.

An ultrasonically assisted two-step polyol process was established to fabricate polycrystalline ZnO nanotubes. Thus one-dimensional (1D) precursors were prepared from an ethylene glycol (EG) solution containing 0.3 M of zinc acetate in the presence of ultrasonic irradiation. The ZnO nanotubes were obtained by calcination of the precursors at proper temperatures. The precursors and polycrystalline ZnO nanotubes obtained at various calcination temperatures were characterized by means of scanning electron microscopy (SEM), Fourier transformation infrared spectrometry (FTIR), x-ray diffraction (XRD, together with temperature-resolved XRD), and transmission electron microscopy (TEM). It was found that the precursors were extremely sensitive to atmospheric moisture and instantly transformed to layered hydroxide zinc acetate (LHS-Zn) after being exposed to air, accompanied by the erosion and deformation of the one-dimensional structure. After being calcined at proper temperatures, the precursors were completely transformed into polycrystalline tubular ZnO, and the sizes of the resulting ZnO nanocrystallites increased with increasing calcination temperature, implying that polycrystalline tubular ZnO of desired sizes could be fabricated using the present method by properly controlling the calcination temperature. However, the tubular structures were destroyed at a calcination temperature of 400 °C and above, owing to the growth of polycrystalline ZnO. Moreover, the present method could be used to synthesize other tubular metal oxides, and tubular ZnO might find promising applications in gas-sensitive sensors and catalysis as well.