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As a novel halogenated hydroxyl ether-inhaled general anesthetic, sevoflurane has been reported to affect the progression of diverse human cancers. In the present study, we aimed to explore the functions and underlying mechanisms of sevoflurane in colon cancer. MTT assay, flow cytometric analysis and Transwell assay were conducted to evaluate cell viability, apoptosis and invasion, respectively. Western blot analysis was performed to determine the protein level of sphingosine-1-phosphate phosphatase 1 (SGPP1). The morphology and size of exosomes were analyzed by TEM and NTA. The levels of circular RNA 3-hydroxy-3-methylglutaryl-CoA synthase 1 (circ-HMGCS1), microRNA (miR)-34a-5p and SGPP1 mRNA were examined by RT-qPCR. Dual-luciferase reporter and RNA RIP assays were utilized to explore the interaction between miR-34a-5p and circ-HMGCS1 or SGPP1. A murine xenograft model was established to investigate the effect of circ-HMGCS1 in vivo . As a result, it was determined that sevoflurane suppressed cell viability and invasion and induced apoptosis in colon cancer in a dose-dependent way. Exosomal circ-HMGCS1 was increased in the serums and cells of colon cancer patients. Circ-HMGCS1 was downregulated by sevoflurane treatment in colon cancer cells and circ-HMGCS1 overexpression could restore the effect of sevoflurane on colon cancer cell development. miR-34a-5p was a target of circ-HMGCS1 and miR-34a-5p inhibition reversed the effect of circ-HMGCS1 silencing on colon cancer cell progression. Moreover, circ-HMGCS1 knockdown suppressed SGPP1 expression via sponging miR-34a-5p. Knockdown of circ-HMGCS1 blocked tumor growth in vivo . In conclusion, sevoflurane inhibited colon cancer progression by modulating the exosome-transmitted circ-HMGCS1/miR-34a-5p/SGPP1 axis.

Fluoroquinolones are frequently used to treat infectious disease that is caused by Escherichia coli in dairy cattle. However, fluoroquinolone resistance occurs and is due either to chromosomal mutations in the bacterial topoisomerase genes and/or to plasmid-mediated resistance genes. The purpose of this study was to determine the prevalence and molecular characteristics of fluoroquinolone resistance determinants in E. coli strains (n=148) isolated from dairy cattle with bovine endometritis in Inner Mongolia (China). Analysis of the mutations in the quinolone resistance-determining regions of resistant E. coli isolates confirmed previously reported substitutions in the GyrA and ParE. However, we identified additional substitutions in the ParC and GyrB that have not been reported earlier. No plasmid-mediated quinolone resistance genes in any of the isolates were found. The number of point mutations found per isolate correlated with an increase in the minimum inhibitory concentration of ciprofloxacin. Overall, 45.5% of the isolates were positive for the class I integrase gene along with four gene cassettes that were responsible for resistance to trimethoprim (dfr1 and dfrA17) and aminoglycosides (aadA1 and aadA5), respectively. The prevalence of extended-spectrum β-lactamases (ESBLs) was 100%, and the blaTEM gene was predominant in all of the isolates. In conclusion, our results identify the mechanism of quinolone resistance for the first time and reveal the prevalence of integron and ESBLs in E. coli isolates from dairy cattle with bovine endometritis in China after 20 years of quinolone usage in cattle.