Xiaofeng Jiang

Purpose: The objective of this study was to investigate the molecular characteristics and potential resistance mechanisms of linezolid-resistant (LZR) Staphylococcus capitis isolates from a tertiary hospital in China. Methods: S. capitis isolates were obtained from clinical patient specimens; three of the isolates came from blood cultures and one from the hydrothorax. The agar dilution and E-test methods were used to identify antibiotic resistance. The chloramphenicol-florfenicol resistance (cfr) gene carrier status of the strains was determined by PCR. Whole-genome sequencing (WGS) was used to identify point mutations and L3, L4, and L22 mutations and to study the genetic environment of the cfr gene and the relationships between strains. Results: The 4 isolates obtained in this study were all linezolid-resistant Staphylococcus strains. A similar of susceptibility profile pattern was observed in all four S. capitis strains, each of which exhibited a multidrug-resistant phenotype. A potentially novel mutation, C2128T, was identified, and the cfr genes of S. capitis strains were all positive. Additionally, the same mutations (C2128T and G2600T) were identified in all 23S rRNA sequences of the isolates, whereas mutations were lacking in the L3, L4, and L22 ribosomal proteins. The genetic environments surrounding cfr were identical in all four isolates. A schematic diagram of the phylogenetic tree showed that they were closely related to AYP1020, CR01, and TW2795, and a total of seven drug resistance genes were identified in these strains. Conclusions: The study indicated that the resistance of the Staphylococcus capitis strains to linezolid was caused by multiple mechanisms, and a potential novel mutation, C2128T, that may have an impact on bacterial resistance was identified.

Purpose: Linezolid is the first oral oxazolidinone antibiotic approved for clinical application. With the widespread use of the linezolid, there are increasing reports of the linezolid-resistant (LZR). The objective of this study was to investigate the molecular characteristics and the potential resistance mechanisms of the LZR Staphylococcus capitis isolates from a tertiary hospital in China.Methods: The agar dilution and E-test methods were used to detect antibiotic resistance. The carrying status of the chloramphenicol-florfenicol resistance (cfr) gene in the strains was detected by PCR. Whole-genome sequencing (WGS) was used to detect point mutations, L3, L4, and L22 mutations, and also to study the genetic environment of the cfr gene and the relationship between strains. Results: A similar pattern in susceptibility profiles were observed in all four S. capitis strains, each exhibiting a multidrug-resistant phenotype. A potential novel mutation, C2128T, was identified, and the cfr genes of S. capitis strains were all positive. Additionally, the same mutation (C2128T and G2600T) was identified in all 23S rRNA sequences of isolates, while the mutation was lacking in the L3, L4, and L22 ribosomal proteins. The genetic environments surrounding cfr were identical in all four isolates. A schematic diagram of the phylogenetic tree exhibited that they were closely related to AYP1020, CR01, and TW2795, and a total of seven drug-resistant genes were detected in these strains. Conclusions: The study indicated that the resistance of the Staphylococcus capitis strains to linezolid was caused by multiple mechanisms and a potential novel mutation C2128T was identified which may have an impact on bacterial resistance.

Multiple myeloma is an incurable refractory hematologic malignancy arising from plasma cells in the bone marrow. Here we investigated miR-26a function in multiple myeloma and tested single-wall carbon nanotube delivery of miR-26a in vitro and in vivo. miR-26a was downregulated in patients with multiple myeloma cells compared with plasma cells from healthy donors. miR-26a overexpression inhibited proliferation and migration and induced apoptosis in multiple myeloma cell lines. To identify the targets of miR-26a, RPMI8226-V-miR-26-GFP and RPMI8226-V-GFP cells were cultured using stable isotope labeling by amino acids in cell culture (SILAC) medium, followed by mass spectrometry analysis. In multiple myeloma cells overexpressing miR-26a, CD38 protein was downregulated and subsequently confirmed to be a direct target of miR-26a. Depletion of CD38 in multiple myeloma cells duplicated the multiple myeloma inhibition observed with exogenous expression of miR-26a, whereas restoration of CD38 overcame the inhibition of miR-26a in multiple myeloma cells. In a human multiple myeloma xenograft mouse model, overexpression of miR-26a inhibited CD38 expression, provoked cell apoptosis, and inhibited cell proliferation. Daratumumab is the first CD38 antibody drug for monotherapy and combination therapy for patients with multiple myeloma, but eventually resistance develops. In multiple myeloma cells, CD38 remained at low level during daratumumab treatment, but a high-quality response is sustained. In daratumumab-resistant multiple myeloma cells, CD38 expression was completely restored but failed to correlate with daratumumab-induced cell death. Therefore, a therapeutic strategy to confer selection pressure to maintain low CD38 expression in multiple myeloma cells may have clinical benefit. Significance: These results highlight the tumor suppressor function of miR-26a via its targeting of CD38 and suggest the therapeutic potential of miR-26a in patients with multiple myeloma.

As one of the isoprenoids and widely derived from many fruits and vegetables, β-ionone (BI) has a potent inhibitory proliferation of cancer cells in vitro and in vivo. However, its exact mechanism is still uncompleted understood and needs to be further verified. Cyclooxygenase-2 (COX-2), as a potential target of cancer chemoprevention, has been played pivotal roles in proliferation of tumor cells and carcinogenesis. Thus, the objective of present study was to determine that BI inhibited the activity of COX-2 in breast cancer and related to cancer cell models. Cell proliferation, DNA synthesis, the distribution of cell cycle, apoptosis induction and the expression of P38-MAPK protein were determined in MCF-7 cells by methylene blue, ³H-thymidine (TdR) incorporation, flow cytometry, TUNEL and Western blotting assays. Quinone reductase (QR) activity was determined in murine hepatoma Hepa1c1c7 cells by enzyme-linked immunosorbent assay (ELISA). The expression of COX-2 in a phorbol-12-myristate-13-acetate (PMA)-induced cell model and mammary tumor tissues was examined by Western blotting and immunohistochemistry. The results showed that BI significantly inhibited cell proliferation and DNA synthesis, arrested the distribution of cell cycle at the S phase or decreased proteins related to cell cycle such as cyclin D1 and CDK4, induced apoptosis and increased the expression of p-P38 in MCF-7 cells. BI at low doses (< 50 μmol/L) significantly increased QR activity, decreased the expression of COX-2 protein and prostaglandin E2 (PEG2) release in cell models. In addition, BI also significantly decreased the expression of COX-2 protein in rat mammary tumor tissues. Therefore, our findings indicate that BI possesses inhibitory proliferation of breast cancer cells through down-regulation of COX-2 activity.

To evaluate the susceptibility rates of aerobic and facultative Gram-negative bacterial isolates from Chinese intra-abdominal infections (IAI) and urinary tract infections (UTI) focusing on carbapenems and comparing their effectiveness between 2014 and 2015. A total of 2318 strains in 2015 (1483 from IAI and 835 from UTI) and 2374 strains in 2014 (1438 from IAI and 936 from UTI) were included in the analysis. Antimicrobial susceptibilities were determined at a central laboratory using CLSI broth microdilution and interpretive standards. Hospital acquired (HA) IAI and UTI were defined as isolates sampled > 48 h and community acquired (CA) as isolates sampled < 48 h after admission. The main species derived from IAI and UTI in 2015 were Escherichia coli (50.86%) and Klebsiella pneumoniae (19.20%). Susceptibilities of Escherichia coli IAI and UTI strains to imipenem (IPM) and ertapenem (ETP) were > 90% in 2014 and 2015, while the susceptibilities to IPM and ETP of Klebsiella pneumoniae IAI strains were > 80% in 2014 but dropped to ≤80% in 2015 for UTI strains. Susceptibilities of IAI Enterobacteriaceae strains to IPM and ETP in 2015 were lowest in the colon and abscesses, and Enterobacteriaceae susceptibilities of UTI and IAI isolates to IPM and ETP were lowest in medical, pediatric and surgery intensive care units (ICUs) in 2015. IPM and ETP were effective in vitro against Enterobacteriaceae isolated from IAIs and UTIs in 2014 and 2015, but susceptibility to carbapenems in UTIs markedly decreased in 2015.

Background/Aims: Cell surface morphology plays pivotal roles in malignant progression and epithelial-mesenchymal transition (EMT). Previous research demonstrated that microvilli play a key role in cell migration of non-small cell lung cancer (NSCLC). In this study, we report that Forkhead box class O1 (FOXO1) is downregulated in human NSCLC and that silencing of FOXO1 is associated with the invasive stage of tumor progression. Methods: The cell proliferation, migration, and invasion were characterized in vitro, and we tested the expression of the Epithelial-mesenchymal transition (EMT) marker by immunofluorescence staining and also identified the effect of FOXO1 on the microvilli by scanning electron microscopy (SEM). Results: Functional analyses revealed that silencing of FOXO1 resulted in an increase in NSCLC cell proliferation, migration, and invasion; whereas overexpression of FOXO1 significantly inhibited the migration and invasive capability of NSCLC cells in vitro. Furthermore, cell morphology imaging showed that FOXO1 maintained the characteristics of epithelial cells. Immunofluorescence staining and western blotting showed that the E-cadherin level was elevated and Vimentin was reduced by FOXO1 overexpression. Conversely, the E-cadherin level was reduced and Vimentin was elevated in cells silenced for FOXO1. Furthermore, scanning electron microscopy (SEM) showed that FOXO1 overexpression increased the length of the microvilli on the cell surface, whereas FOXO1 silencing significantly reduced their length. Conclusions: FOXO1 is involved in human lung carcinogenesis and may serve as a potential therapeutic target in the migration of human lung cancer.

An increase in serum homocysteine level has been associated with an increased risk of vascular disease; however, the biochemical mechanisms that underlie these effects remain largely unknown. The present study aimed to use high-performance liquid chromatography-mass spectrometry (HPLC‑MS) to demonstrate the effects of serum homocysteine on human blood metabolites. A total of 75 fasting serum samples were investigated in the present study. Using a threshold of 15 µmol/l serum homocysteine level, samples were divided into high‑ and low‑homocysteine groups, and the serum extracts were analyzed with an HPLC‑MS‑based method. A total of 269 features exhibited significant differences and correlation with serum homocysteine levels in the electrospray ionization‑positive [ESI(+)] mode, and 69 features were identified in the ESI(‑) mode between the two groups. The principal component analysis plot revealed a separation between the high‑ and the low‑homocysteine groups. Metabolite set enrichment analysis identified arachidonic acid metabolism and linoleic acid metabolism as the two pathways with significantly enriched differences. These results revealed that arachidonic acid and linoleic acid metabolism may be associated with serum homocysteine levels and may be involved in homocysteine-induced vascular disease.

Aims The frequency of X chromosome pericentric inversion is much less than that of autosome chromosome. We hereby characterise a pericentric inversion of X chromosome associated with severe factor VIII (FVIII) deficiency in a sporadic haemophilia A (HA) pedigree. Methods PCR primer walking and genome walking strategies were adopted to identify the exact breakpoints of the inversion. Copy number variations (CNVs) of the F8 and the whole chromosomes were detected by AccuCopy and Affymetrix CytoScan High Definition (HD) assays, respectively. A karyotype analysis was performed by cytogenetic G banding technique. Results We identified a previously undescribed type of pericentric inversion of the X chromosome [inv(X)(p11.21q28)] in the proband with FVIII:C F8, which disrupted the transcription of the F8, and the other located in the upstream of the PFKFB1 of the X chromosome. The inversion segment was approximately 64.4% of the total chromosomal length. The karyotype analysis of the X chromosome confirmed the pericentric inversion of the X chromosome in the proband and his mother. A haplotype analysis traced the inversion to his maternal grandfather, who was not a somatic mosaic of the inversion. This finding indicated that the causative mutation may originate from his germ cells or a rare possibility of germ-cell mosaicism. Conclusions The characterisation of pericentric inversion involving F8 extended the molecular mechanisms causing HA. The pericentric inversion rearrangement involves F8 by non-homologous end joining is responsible for pathogensis of severe HA.

Slightly increased pressure stimulates tumor cell adhesion and proliferation. In the present study, we aimed to evaluate the effects of high pressure on gene expression and the biological behavior of gastric cancer cells. After incubation for 30 min at 37˚C under ambient and increased pressure, one portion of SGC7901 cells was used for cell proliferation and apoptosis assays, cell cycle analysis, adhesion invasion or migration assays. The other portion of cells was harvested for detection of matrix metalloproteinase-2 (MMP-2), inhibitor of DNA binding-1 (ID1), sonic Hedgehog (SHH) and E-cadherin expression by western blotting or RT-PCR. In addition, we investigated the effects of high pressure on SGC7901 cell ultrastructure by transmission electron microscopy. We found that the adhesion fold under increased pressure of 760 and 1,520 mmHg was 2.39±1.05 (P<0.05) and 2.47±0.85 (P<0.01) as compared with the control, respectively. The invasion fold was 3.42±2.06 (P<0.05) and 5.13±2.49 (P<0.01) as compared with the control, respectively. The migration was 1.65±0.20 (P<0.001) and 2.53±0.50 (P<0.001) as compared with the control, respectively. At increased pressure, MMP-2 and ID1 expression increased significantly, while the expression of SHH decreased significantly. However, we did not find significant change in proliferation, apoptosis, cell cycle or ultrastructure of the SGC7901 cells under high pressure. In conclusion, high pressure promoted the adhesion, invasion and migration of SGC7901 cells. Moreover, the present study suggests that the pressure-augmented invasion and migration may be related to the increase in MMP-2 expression. Moreover, high pressure may suppress SGC7901 cell differentiation, which may result from the change in SHH and ID1 expression.

Esophageal squamous cell carcinoma (ESCC) is a leading cause of cancer-related deaths worldwide. The high mortality of ESCC is mainly due to late diagnosis. Current detection methods have their own weakness, including high costs and invasive procedures. MicroRNA assays are shown to have great potential to be accurate and noninvasive methods for ESCC screening. In this study, we selected 3 microRNAs, miR-10b, miR-29c, and miR-205, to assess their diagnostic value in ESCC screening. Fifty ESCC patients and 50 healthy controls are recruited in our study. Blood samples are collected from the total 100 participants. MicroRNAs were extracted from serum and quantified by qRT-PCR, which their relative expressions were normalized by internal control, U6 snRNA. Statistical analyses were conducted to compare microRNAs level as well as other clinical characteristics between 2 groups. The levels of serum miR-29c and miR-205 were significantly downregulated in ESCC patients compared with healthy volunteers. In contrast, ESCC patients appeared to have a higher level of miR-10b than healthy controls. ROC curve analyses revealed that the AUC value for miR-10b, miR-29c, and miR-205 were 0.85 (95% CI: 0.79-0.93; sensitivity = 76%; specificity = 84%), 0.72 (95% CI: 0.62-0.82; sensitivity = 68%; specificity = 68%), and 0.72 (95% CI: 0.62-0.83; sensitivity = 70%; specificity = 64%), respectively, suggesting that miR-10b, miR-29c, and miR-205 have great potential to be noninvasive screening tools for ESCC detection.