Molecular characteristics of Acinetobacter baumannii and the changes of efflux pump expression under tigecycline pressure / 医学研究生学报

Objective　Acinetobacter baumannii (A. baumannii) is a commonly infective bacterium in the hospital. This study aims to analyze its molecular epidemiological characteristics, detect the carrying rate of efflux pump and regulatory protein genes, and investigate the effects of tigecycline on the efflux pump and expression of regulatory protein genes.　Methods　A total of 183 A. baumannii strains were collected from inpatients of the affiliated hospital of Jiangsu University from May 2017 to March 2019. They were divided into an antimicrobial-resistant group (one or more antimicrobial-resistant strains, 139 strains) and a sensitive group (the drugs in the drug sensitivity test were all non-resistant strains, 44 strains). Repeated sequence PCR was used for homology analysis of the strains, and pulse-field gel electrophoresis (PFGE) was used as the gold standard for homology analysis to verify and compare some strains. PCR was used to detect the occurrence of drug resistance-related genes. Based on homology analysis, efflux pump carrying rate detection and antibiotics sensitivity test results, 6 clinical strains carrying all efflux pump genes but different resistance phenotypes were selected as experimental strains, including sensitive strains (SAB), the multidrug resistance strain (MDRAB) and the extensively drug-resistant strain (XDRAB). All strains were induced in vitro with the minimum inhibitory concentration (MIC) of tigecycline. The induced strains were categorized as induction group, and the same strains cultured in LB agar without tigecycline was used as a control group. MIC was used to analyze the tigecycline susceptibility, and RT-qPCR was used to detect the gene expression of efflux pumps, such as TetB, AbaQ and regulatory proteins (AdeS and BaeS), in drug-resistant strains.　Results　Homology analysis showed that there were 45 clonal groups in the detected clinical isolates, with no obvious outbreak of epidemic clonal groups. Efflux pumps and regulatory proteins were widely distributed in the clinical isolates, and the expression of AdeB, TetB, AbeS, AdeS in MDRAB and XDRAB is significantly higher than that insensitive group SAB. Continuous in vitro induction with tigecycline could increase the antimicrobial resistance of some clinical strains and even significantly increase the expression levels of efflux pumps and regulatory proteins.　Conclusion　A. baumannii is widely distributed in the clinic, and efflux pumps and regulatory proteins might play an important role in drug resistance process. The unreasonable use of tigecycline could enhance the tolerance of A. baumannii by up-regulating the expression of some bacterial efflux pumps.

Expression of TLR8 in human cervical cancer HeLa cells and the effect of TLR8 agonist on the cell proliferation and apoptosis / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To observe the expression of Toll-like receptor 8 (TLR8) in human cervical cancer cell-line HeLa cells, and the effects of TLR8 agonist CL075 on the survival and proliferation of HeLa cells.</p><p><b>METHODS</b>PCR and RT-PCR were used to detect the expression of TLR8 in 13 cancer cell lines, and the expression of COX-2, Bcl-2, VEGF mRNA in the HeLa cells stimulated by TLR8 agonist CL075 were also measured by RT-PCR. Immunofluorescence technique was used to determine the exact location of TLR8 in the cells. The percentage of viable cells was determined by trypan blue exclusion after the HeLa cells were stimulated with TLR8 agonist CL075 (0.1 µg/ml, 0.5 µg/ml, 1.0 µg/ml, 2.5 µg/ml), and cell cycle and apoptosis were analyzed by flow cytometry, and the proliferation was measured by MTT.</p><p><b>RESULTS</b>Compared with the other cancer cell lines, the expression of TLR8 in HeLa cells was the highest (703.7 ± 20.6). After stimulation by CL075, the cells had a remarkable increase of the percentage of cells in G(2)/M + S phases. In the control group, the percentage of cells in G(2)/M +S phases was (39.02 ± 2.33)%, whereas after stimulated with 1.0 µg/ml CL075, the percentage of cells in G(2)/M + S phases reached the highest ratio (57.67 ± 1.73)%, and the percentage of cells in G(2)/M + S phases had a less decrease after 2.5 µg/ml CL075 stimulation and the percentage was (56.14 ± 3.73)%. After the CL075 treatment, there was no significant changes of apoptosis compared with that of the control cells (P > 0.05), but after DDP treatment the apoptosis had a significant change (P < 0.01). After stimulation by 1.0 µg/ml CL075 for 24 h, no significant difference (P > 0.05) was found by MTT test, but a significant difference was found at 48 h and 72 h (P < 0.01). An increased expression of COX-2, Bcl-2 and VEGF mRNA was observed in HeLa cells after stimulation by TLR8 agonist CL075 for 24 h and 48 h (P < 0.05).</p><p><b>CONCLUSIONS</b>Expression of TLR8 is significantly increased in HeLa cells. The proportion of cells at different phases has a significant change after CL075 stimulation, which may up-regulate the proliferation of HeLa cells. These data suggested that TLR8 agonist may influence the tumor development and TLR8 may become a potential target in the treatment for cervical cancer.</p>

Detection and significance of transcription factors and cytokines of Th17/Treg cells in peripheral blood in the gastric cancer patients / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To detect the expression levels of transcription factors and associated cytokines of Th17 and Treg cells in peripheral blood mononuclear cells (PBMC) of patients with gastric cancer, and explore the possible pathological mechanism of these cells involved in the development of gastric cancer.</p><p><b>METHODS</b>The mRNA levels of RORgammat, FoxP3 in PBMC were determined by quantitative real-time PCR (QRT-PCR) from 57 patients with gastric cancer, 31 patients with benign gastric illness and 40 healthy people. The concentration of IL-17, IL-23, TGF-beta, IL-10 in plasma were detected by enzyme linked immunosorbent assay (ELISA).</p><p><b>RESULTS</b>Compared with healthy volunteers, patients with gastric cancer showed higher levels of RORgammat and FoxP3 in PBMC (P < 0.05). The ratio of FoxP3/RORgammat in gastric cancer group was higher than that in the volunteer group and benign gastric illness group (P < 0.05). The ratio of FoxP3/RORgammat was higher in advanced disease than early disease (P < 0.05). The expressions of IL-17, IL-23, TGF-beta and IL-10 were higher in patients with gastric cancer than that in healthy volunteers (P < 0.05). In addition, The expression of TGF-beta and IL-10 were significantly increased in the advanced disease group than that in the early group (P < 0.05), but IL-17 and IL-23 was not significantly changed between the two groups (P > 0.05).</p><p><b>CONCLUSION</b>There are higher levels of Th17 and Treg cells in gastric cancer patients, and it also shows a persistent predominant tendency of Treg cells and a reduced tendency of Th17 cells in advanced disease. Detecting the expression of Th17/Treg transcription factor and related cytokines would contribute to the diagnosis and prediction of the disease development and prognosis.</p>