Objective: To provide the epidemiology, resistance pattern, and characterization of integrons in Shigella flexneri isolated between 2001 and 2011 in Jiangsu Province. Method: A total of 624 strains of S. flexneri were collected from both outpatients and inpatients in hospitals in Jiangsu Province from January 2001 to December 2011. The Kirby–Bauer disk diffusion method was used to perform the antimicrobial susceptibility test. Polymerase chain reaction (PCR) was used in the detection of integrons. Pulsed-field gel electrophoresis (PFGE) was applied in the homology studies. Result: Serotype 2a accounted for the largest proportion in S. flexneri, namely 26.4 %. Notably, an increasing trend was detected in the resistance to common antimicrobial agents during the period 2001–2011. In recent years, more than 80.0 % isolates of S. flexneri have proved to be resistant to ampicillin, nalidixic acid, and tetracycline. The positive rates of class 1, class 2, and the atypical class 1 integrons in S. flexneri are 69.3 %, 87.8 %, and 89.2 % respectively. Most integrons detected in our research carry genes encoding resistance to trimethoprim and streptomycin. Conclusion: Antimicrobial resistance in S. flexneri has demonstrated a continuous rising trend in Jiangsu Province. A high prevalence of integrons and gene cassettes play an important role in the transmission of drug resistance in S. flexneri. Effective measures are urgently needed to control the spread of multi-drug-resistant S. flexneri, and more continuing active surveillance of antimicrobial resistance should be established worldwide, especially in developing countries.

Patients with non-small-cell lung cancer (NSCLC) have immune defects that are poorly understood. Forkhead box protein P3 (Foxp3) is crucial for immunosuppression by CD4+ regulatory T cells (Tregs). It is not well known how NSCLC induces Foxp3 expression and causes immunosuppression in tumor-bearing patients. Our study found a higher percentage of CD4+ Tregs in the peripheral blood of NSCLC compared with healthy donors. NSCLC patients showed demethylation of eight CpG sites within the Foxp3 promoter with methylation ratios negatively correlated with CD4+CD25+Foxp3+ T levels. Foxp3 expression in CD4+ Tregs was directly regulated by Foxp3 promoter demethylation and was involved in immunosuppression by NSCLC. To verify the effect of tumor cells on the phenotype and function of CD4+ Tregs, we established a coculture system using NSCLC cell line and healthy CD4+ T cells and showed that SPC-A1 induced IL-10 and TGF-β1 secretion by affecting the function of CD4+ Tregs. The activity of DNA methyltransferases from CD4+ T was decreased during this process. Furthermore, eight CpG sites within the Foxp3 promoter also appeared to have undergone demethylation. Foxp3 is highly expressed in CD4+ T cells, and this may be caused by gene promoter demethylation. These induced Tregs are highly immunosuppressive and dramatically inhibit the proliferative activity of naïve CD4+ T cells. Our study provides one possible mechanism describing Foxp3 promoter demethylation changes by which NSCLC down-regulates immune responses and contributes to tumor progression. Foxp3 represents an important target for NSCLC anti-tumor immunotherapy.

Inflammation has been implicated in the initiation and progression of ovarian cancer (OC), the underlying mechanisms of which are still unclear. We hypothesized that the abnormal expression of Toll-like receptors (TLRs), which were potential activators of nuclear factor-kappa B p65 (NF-κB p65), could promote inflammation and tumorigenesis in OC. In this study, we characterized the expression of TLRs in peripheral blood mononuclear cells (PBMCs) and found TLR2 and TLR6 mRNAs levels to be higher in PBMCs from OC patients than in those from benign disease (BC) or healthy normal controls (NC). Flow cytometry analysis showed that TLR1, TLR2 and TLR6 were highly expressed in monocytes from OC patients, but not in those from control subjects. Consistently, inflammatory cytokines interleukin (IL)-1β and IL-6 were up-regulated in PBMCs from OC patients upon stimulation with Pam3CSK4 (TLR1 ligand) and HKLM (TLR2 ligand), compared with unstimulated PBMCs. Stimulation of PBMCs with TLR ligands led to activation of downstream signaling molecules in TLRs (MyD88, TRAF6, TANK, NF-κB p65 and p-NF-κB p65). We also discovered that SK-OV-3-secreted factors were potent PBMCs activators, leading to the production of IL-1β, IL-6 and IL-8 through activation of TLRs and downstream signaling molecules in PBMCs. Before coculturing with SK-OV-3, pretreatment of THP-1 cells or PBMCs with monoclonal antibodies against TLR1, TLR2 or TLR6 inhibited the production of IL-1β and IL-6 and activation of MyD88, TRAF6, TANK, NF-κB p65 and p-NF-κB p65. Our results provided new evidence that TLR1, TLR2 and TLR6 signaling was linked with inflammation in OC microenvironment.

MicroRNAs (miRNAs), a class of small non-coding RNAs, mediate gene expression by either cleaving target mRNAs or inhibiting their translation. They have key roles in the tumorigenesis of several cancers, including non-small cell lung cancer (NSCLC). The aim of this study was to investigate the clinical significance of miR-638 in the evaluation of NSCLC patient prognosis in response to chemotherapy. First, we detected miR-638 expression levels in vitro in the culture supernatants of the NSCLC cell line SPC-A1 treated with cisplatin, as well as the apoptosis rates of SPC-A1. Second, serum miR-638 expression levels were detected in vivo by using nude mice xenograft models bearing SPC-A1 with and without cisplatin treatment. In the clinic, the serum miR-638 levels of 200 cases of NSCLC patients before and after chemotherapy were determined by quantitative real-time PCR, and the associations of clinicopathological features with miR-638 expression patterns after chemotherapy were analyzed. Our data helped in demonstrating that cisplatin induced apoptosis of the SPC-A1 cells in a dose- and time-dependent manner accompanied by increased miR-638 expression levels in the culture supernatants. In vivo data further revealed that cisplatin induced miR-638 upregulation in the serum derived from mice xenograft models, and in NSCLC patient sera, miR-638 expression patterns after chemotherapy significantly correlated with lymph node metastasis. Moreover, survival analyses revealed that patients who had increased miR-638 levels after chemotherapy showed significantly longer survival time than those who had decreased miR-638 levels. Our findings suggest that serum miR-638 levels are associated with the survival of NSCLC patients and may be considered a potential independent predictor for NSCLC prognosis.

Integrons are gene capture and expression systems that are characterized by the presence of an integrase gene. This encodes an integrase, a recombined site, and a promoter. They are able to capture gene cassettes from the environment and incorporate them using site-specific recombination. The role of integrons and gene cassettes in the dissemination of multidrug resistance in Gram-negative bacteria is significant. In Shigella species, antimicrobial resistance is often associated with the presence of class 1 and class 2 integrons that contain resistance gene cassettes. Multiple and complex expression regulation mechanisms involving mobile genetic elements in integrons have been developed in the evolution of Shigella strains. Knowledge of the epidemiology and molecular mechanisms of antimicrobial resistance in this important pathogen is essential for the implementation of intervention strategies. This review was conducted to introduce the structures and functions of integrons in Shigella species and mechanisms that control integron-mediated events linked to antibiotic resistance.

DNA methylation plays an essential role in maintenance of cellular function. A growing number of human diseases have been found to be associated with aberrant DNA methylation, especially cancer. However, current technologies used in DNA methylation detection are complicated and time consuming. A promotor of the Adenomatous polyposis coli (APC) gene, a well-studied tumor suppressor gene, was used as the detection target DNA sequence. The double recognition mechanism was realized with oligonucleotide probe hybridization and specific protein binding. First, complementary target DNA was captured by the probe immobilized onto a surface plasmon resonance (SPR) sensor chip. Then, the recombinant methyl-CpG binding domain (MBD) protein was passed over the surface to recognize and bind to methylated CpG sites. Binding resulted in an increase in the refractive index, and a detectable optical signal was generated. Five picomoles of methylated APC promotor DNA could be easily detected with this method. The entire detection could be completed within 1 h. This work represents the first SPR based biosensor technology, which achieves simple and specific DNA methylation detection and avoids complicated bisulfite treatment and methylation-sensitive restriction digestion. It will improve our ability to detect DNA methylation specifically and rapidly, and promote our understanding of the role of DNA methylation in gene regulation and diseases.

Shigella is becoming an increasing public health problem due to development of multiple antimicrobial resistance, frequently resulting in treatment failure. A systematic review was conducted based on a literature search of computerised databases. Random or fixed-effects models were used, based on the P-value considering the possibility of heterogeneity between studies, for meta-analysis. Statistical analyses were performed using STATA 10.0. In the area of Asia–Africa, resistance rates to nalidixic acid and ciprofloxacin were 33.6% [95% confidence interval (CI) 21.8–46.6%] and 5.0% (95% CI 2.8–7.8%), respectively, 10.5 and 16.7 times those of Europe–America. Moreover, resistance to nalidixic acid and ciprofloxacin in Asia–Africa progressively increased each year, reaching 64.5% (95% CI 13.8–99.3%) and 29.1% (95% CI 0.9–74.8%), respectively, in 2007–2009, whilst isolates in Europe–America remained at low levels of resistance (<5.0% and <1.0%, respectively). All Shigella flexneri strains showed higher resistance than Shigella sonnei in Europe–America: overall, 3.5% (95% CI 1.4–6.4%) vs. 2.6% (95% CI 1.0–5.0%) resistant to nalidixic acid and 1.0% (95% CI 0.3–2.2%) vs. 0.1% (95% CI 0.0–0.3%) resistant to ciprofloxacin. In Asia–Africa, a similar trend was found for ciprofloxacin [3.0% (95% CI 1.4–5.3%) vs. 0.5% (95% CI 0.2–0.8%)], whereas the trend was reversed for nalidixic acid [32.6% (95% CI 14.5–53.9%) vs. 44.3% (95% CI 26.9–62.5%). In conclusion, quinolone resistance in Shigella has increased at an alarming speed, reinforcing the importance of continuous monitoring of antimicrobial resistance in Shigella.

One hundred and forty-two Enterobacteriaceae isolates randomly selected from four general hospitals in Nanjing region of China were investigated for antibiotic susceptibility, the presence of integrons and the characterisation of gene cassettes. Eighty-five (59.9%) Enterobacteriaceae strains contained class 1 integrons, and 17 (65.4%) of 26 Shigella contained class 2 integrons. Class 3 integrons were not detected in this study. Restriction fragment length polymorphism (RFLP) and DNA sequencing analysis revealed seven different cassette arrays of class 1 integrons; additionally, four cassette arrays identified in this study were reported for the first time in some species. The genes most commonly found in these class 1 integrons were those for aminoglycoside and trimethoprim resistance. In conclusion, class 1 and 2 integrons were widespread in Enterobacteriaceae and Shigella, respectively, in Nanjing area of China and it was likely that integrons played an important role in antibiotic resistance. Characterisation of cassette arrays of integrons could be a useful epidemiological tool to study the evolution of multidrug resistance and the dissemination of antibiotic resistance genes.