The effect of DNA-PKcs gene silencing on proliferation, migration, invasion and apoptosis, and in vivo tumorigenicity of human osteosarcoma MG-63 cells.

The purpose of this study was to explore the role by which the DNA-dependent protein kinase complex catalytic subunit (DNA-PKcs) influences osteosarcoma MG-63 cell apoptosis, proliferation, migration and invasion. Osteosarcoma tissues and adjacent normal tissues were obtained from 57 osteosarcoma patients. Human osteosarcoma MG-63 cells were assigned into designated groups including the blank, siRNA-negative control (NC) and siRNA-DNA-PKcs groups. RT-qPCR and Western blotting methods were employed to evaluate the mRNA and protein expressions of DNA-PKcs. A cell counting kit-8 (CCK-8) assay was performed to assess cell viability. The evaluation of cell migration and invasion were conducted by means of Scratch test and Transwell assay. Flow cytometry with PI and annexin V/PI double staining was applied for the analysis of the cell cycle and apoptosis. Twenty-Four Balb/c nude mice were recruited and randomly divided into the blank, siRNA-NC and siRNA-DNA-PKcs groups. Tumorigenicity of the Balb/c nude mice was conducted to evaluate the rate of tumor formation, as well as for the assessment of tumor size and weight, and confirm the number of lung metastatic nodules in the mice post transfection. Osteosarcoma tissues were found to possess greater expression of DNA-PKcs than that of the adjacent normal tissues. DNA-PKcs expression in osteosarcoma tissues were correlated with the clinical stage and metastasis. Compared with the blank and siRNA-NC groups, proliferation, miration, as well as the invasion abilities of the MG-63 cells increased. Furthermore, an increase in apoptosis and cells at the G1 stage in the MG-63 cells was observed, while there were reductions in the cells detected at the S stage. The mRNA and protein expressions of CyclinD1, PCNA, Bcl-2 decreased while those of Bax increased in the siRNA-DNA-PKcs group. The tumor formation rate, tumor diameter, weight and lung metastatic nodules among the nude mice in the siRNA-DNA-PKcs group were all lower than those in the blank and siRNA-NC groups. The observations and findings of the study suggested that the silencing of DNA-PKcs inhibits the proliferation, migration and invasion, while acting to promote cell apoptosis in MG-63 cells and osteosarcoma growth in nude mice.

[Degradation of m-Cresol with Fe-MCM-41 in Catalytic Ozonation].

Fe-MCM-41 was first used for the treatment of m-cresol in catalytic ozonation. The effect of the percentage of Fe dopping mass, catalyst dosage and the natural concentration of substrate on m-cresol conversion and TOC removal were studied. The structural property of Fe-MCM-41 was characterized by X-ray diffraction, temperature-programmed reduction, Mössbauer spectra and BET of catalysts. The results showed that Fe dopping mass had a great effect on the catalytic activity of Fe-MCM-41 in catalytic ozonation and the optimal percentage of dopping mass was 4.4% (wt). The results showed that with Fe dopping mass increase, the degree of crystallinity became weaker, the crystal surface distance reduced, as well as the specific surface area, pore volume and aperture. γ-Fe2O3 was the only form staying on the surface of MCM-41, and the catalyst had good ferromagnetism and stability. Ozonation played a role of both direct oxidation and indirect oxidation in the reaction, approximately the same ratio. Under the experimental condition of the natural pH of model wastewater,using 4.4% (wt) Fe-MCM-41 as catalyst, natural concentration of m-cresol 500 mg x L(-1), catalyst dosage 0.1 g x L(-1) and reaction time 30 min, m-cresol conversion and TOC removal were 100% and 26.8%, respectively.

Molecular variability of DR-1 and DR-2 within the pvpA gene in Mycoplasma gallisepticum isolates.

A total of 15 Mycoplasma gallisepticum (MG) isolates from Chinese poultry farms and three reference strains (S6, BG44T, and F36) were characterized by nested polymerase chain reaction and sequence analysis for two identical and directly repeated sequences, DR-1 and DR-2, within the putative cytadhesin pvpA gene. The molecular variation patterns of the pvpA genes among the 15 MG isolates were identical to the reference strains S6 and BG44T, that is, a 60 bp deletion in DR-1 and DR-2 and repetition of 1) a proline residue 33 times and 2) a tetrapeptide motif 10 times (Pro-Arg-Pro-X, where X is Met, Gly, Asn, or Gln for 6, 1, 1, or 2 times, respectively). However, the variation pattern is quite different from that of the vaccine strain F36, in which only the DR-1 region is retained, 24 of the 25 peptides comprising the linkage sequence between DR-1 and DR-2 are missing, and the entire DR-2 sequence is deleted. A comparison of the sequences within the DR-1 and DR-2 repeated regions among clinical isolates from different geographic sites suggested that > or = 30 proline residue repeats and 7-10 repeats of the tetrapeptide motif may exert an important role in the functionality of PvpA as an adhesin molecule. Size variation and differences in deletion patterns in the C-terminal coding region of the pvpA gene were observed among the field isolates and vaccine strain F, providing the basis for strain differentiation.