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Objective:To investigate the effect of lncRNA HOTTIP on the radiosensitivity of four non-small cell lung cancer cell lines cultured in vitro by regulating the expression of miR-663a. Methods:Four non-small cell lung cancer cell lines (H838, H157, A549, and H1299) were irradiated with different radiation intensities (0, 2, 4, 6, and 8 Gy). Cell survival was detected by colony formation assay. The expression levels of HOTTIP and miR-663a were detected by qRT-PCR. A549 and H1299 cells were selected for the subsequent experiment. After silencing HOTTIP and/or over-expressing miR-663a, cell survival was detected by colony formation assay. Cell apoptosis was detected by flow cytometry. The expression levels of Cleaved caspase-3, Cleaved PARP andγ-H 2AX were quantitatively measured by Western blot. The targeting relationship between HOTTIP and miR-663a was vefiried by dual luciferase reporter assay and qRT-PCR. Results:The expression of HOTTIP was up-regulated, whereas that of miR-663a was down-regulated in the radiation-resistant H157, A549 and H1299 cells. Silencing HOTTIP or over-expressing miR-663a inhibited the survival of A549 and H1299 cells (radiosensitization ratios were 1.562 and 1.507, respectively), promoted the expression of Cleaved caspase-3, Cleaved PARP and γ-H 2AX, and accelerated cell apoptosis induced by radiation exposure. miR-663a was a target gene of HOTTIP, and HOTTIP negatively regulated the expression of miR-663a. The inhibition of miR-663a reversed the effect of silencing HOTTIP on the radiosensitivity of non-small cell lung cancer cells. Conclusion:Silencing HOTTIP can suppress the survival of non-small cell lung cancer cells and promotes cell apoptosis by up-regulating the expression of miR-663a, thereby enhancing the radiosensitivity of non-small cell lung cancer cell lines.
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Objective To clone the gene encoding protein of EspA and Stx2B from EHEC OI57:H7 by DNA recombinant technology, construct prokaryotic expression vector pET-28a ( + )-espAstx2B, express fusion protein of EspA-Stx2B and to analyze the biological and immunological characteristics of the fusion protein. Methods the sequence encoding the protein of EspA and Stx2B was amplified by PCR from the enterohemorrhagic Escherichia coli strain. The amplified products were connected with linker by recombinant technology and cloned into pET-28a( + ) vector. The vector was then transferred to the host cells E. Coli BL21 strain (DE3). Following, the protein expression was induced by IPTG. The expression quantities and style of fusion protein was then determined by SDS-PAGE. Its immunoreactivity was analyzed by Western blot. Finally, BALB/c mice were injected with the preliminarily purified recombination protein EspA-Stx2B, then oral challenged these mice with EHEC O157-SMR2 and counteracted toxic substances with O157 ultrasonic supernatant. Results The determination of the sequence encoding of the espA-stx2B fusion gene has 100% of consistency with the sequence from GenBank Sakai strain and contrivable linker. This fusion protein EspA-Stx2B was expressed as inclusion body formation and the percentage is approximately 40%. Western blot suggested the fusion protein has excellent immunoreactivity. Titer of antiserum of the mice to EspA-Stx2B increased evidently. EspA-Stx2B could not decrease bacterial number attached to the intestinal tract of mice based on fecal shedding of Oi57 in mice. In the test of death of BAI,B/c causing by conteracting toxic substances with O157 ultrasonic supernatant, immunoprotection of EspA-Stx2B rate was 66.7%. Conclusion A recombinant plasmid that has high performance on expression of EspA-Stx2B prorein was successfully constructed in present study, and the fusion protein has excellent immunoreactivity and immunogenicity. EspA-Stx2B could not decrease bacteria] number attached to the intestinal tract of mice based on fecal shedding of O157 in mice, but evidently decrease the mortality rate of the mice. The antiEspA and anti-Stx2B had immunoprotection effect by different means. These results may provide the foundation for the further development on EHEC O157:H7 double subunit vaccine.
RESUMEN
Objective To investigate immunoprophylactic potential of genetic engineering vaccines of enterohaemorrhagie Escherichia coli O157:H7 in BALB/c mice after immunization with these vaccines. Methods Sixty BALB/c mice (3 weeks old) were randomized averagely into 5 groups. Group 1-3 were im-munized respectively with IntiminC300, Stx2B and HIyAN436, group 4 with a combination of these three vaccines, and group 5 with PBS. Each mouse was immunized with vaccine(100 μg)and Al(OH)3 adjuvant (100 μg) for 3 times. After 7 d of the second and third immunization, serum of each mouse was collected and the different antibodies were detected. After 10 d of the last immunization, all mice were given drinking water containing streptomycin for 3 d before and following oral challenge with O157:H7 (109 CFU), and treated with clinical, microbiological and pathological examination. Results The three vaccines elicited high titer antiserum, and some mice were died after infection with O157. The livability of group 1-4 was re-spectively 73%, 64%, 36% and 91%. And these vaccines depressed fecal and colon shedding with O157. Condusion IntiminC300, Stx2B and HIyAN436 have certain protective efficacy for infection of O157, and combined immunization was more effective than single vaccine.