Yuan Lu

Publications of Yuan Lu

• The profile of Th17 subset in glioma.

  Authors: Jinhui Hu, Ying Mao, Min Li, Yuan Lu

  International immunopharmacology. 04/2011; 11(9):1173-9.

  The Th17 cell subset is involved in many autoimmune and infectious pathologies. It is also associated with the tumorigenesis process and poor prognosis of certain tumors. However, its expression andThe Th17 cell subset is involved in many autoimmune and infectious pathologies. It is also associated with the tumorigenesis process and poor prognosis of certain tumors. However, its expression and function in glioma cases remain unclear. We measured the percentage of Th17 cells in peripheral blood mononuclear cells (PBMCs) and compared the concentrations of relevant cytokines in the serum of 35 glioma patients and 20 healthy donors. Protein, mRNA, and levels of Th17-relevant cytokines in 24 glioma tissues and 5 cerebral trauma tissues were also assessed. We evaluated whether Th17-relevant cytokines were associated with the clinical stages of glioma. The results showed that there were no significant differences in the volume of Th17 cells in PBMCs and serum concentrations of interferon (IFN)-γ, interleukin (IL)-17, IL-6, IL-23, and TGF-β between glioma patients and healthy donors nor did these differences exist in patients with different clinical stages of glioma. Different expression patterns of Th17-relevant cytokines were observed in glioma tissues when compared to trauma tissues. High mRNA-positive ratios of IL-17 (19/24) and retinoid-related orphan receptor (RORC) (18/24) were observed in glioma tissues, but not in trauma tissues. Positive ratios of transforming growth factor (TGF)-β were higher in trauma tissues and glioma grade II than in glioma grade IV. IL-6, IFN-γ, and IL-1β showed high positive ratios, but showed no significant differences between trauma tissues or grades of glioma. None of the glioma and trauma tissues was positive for IL-23. High positive ratios of IL-17 in glioma tissue were confirmed via analysis of immunohistochemical staining. The results demonstrated that IL-17 and other Th17-relevant cytokines could be expressed in glioma tissues. IL-17 expression, the hallmark of Th17 cell subset, may play an important role in glioma tumorigenesis and progression.

• Transcription of integron-harboured gene cassette impacts integration efficiency in class 1 integron.

  Authors: Quhao Wei, Xiaofei Jiang, Min Li, Xiaoyun Chen, Gang Li, Ru Li, Yuan Lu

  Molecular microbiology. 04/2011; 80(5):1326-36.

  Class 1 integrons play important roles in the dissemination of antibiotic resistance genes among bacteria. Generally, class 1 integron consists of an integrase gene (intI1), a recombination siteClass 1 integrons play important roles in the dissemination of antibiotic resistance genes among bacteria. Generally, class 1 integron consists of an integrase gene (intI1), a recombination site (attI1) and a promoter (Pc) that drives the transcription of the downstreamed gene cassettes. Occasionally, there is a second promoter P2 downstream of the Pc promoter. Several Pc variants and Pc-P2 combinations have been defined and they display different transcription strengths, but the influence of the transcription of integron-harboured gene cassette on the integration efficiency has never been comprehensively studied. In this study, the integration frequencies of gene cassettes into the attI1 sites that downstream of four different Pc variants as well as their combinations with P2 promoter were measured. The results showed that there was an inverse correlation between the strength of Pc promoter and the integration efficiency and, with the same Pc promoter, the integration efficiency was significantly decreased when a P2 promoter preceded the attI1 site. Our findings indicate there is a relationship between the transcription of integron-harboured gene cassette and the integration of exogenous gene cassettes. The interrelationship between these two relatively independent processes may throw a light on our understanding the regulation system of class 1 integron.

• Quantitative assessment of AKAP12 promoter methylation in human prostate cancer using methylation-sensitive high-resolution melting: correlation with Gleason score.

  Authors: Weiwei Liu, Jian Gong, Jinghui Hu, Tingting Hu, Yaofei Sun, Junhua Du, Chuanyu Sun, Ming Guan, Haowen Jiang, Yuan Lu

  Urology. 02/2011; 77(4):1006.e1-7.

  To quantitatively investigate the A kinase anchoring protein 12 (AKAP12) gene promoter methylation and its association with clinicopathologic variables in human prostate cancer (PCa). The AKAP12 geneTo quantitatively investigate the A kinase anchoring protein 12 (AKAP12) gene promoter methylation and its association with clinicopathologic variables in human prostate cancer (PCa). The AKAP12 gene has shown reduced expression and marked hypermethylation in a variety of cancers. The percentage levels of DNA methylation were measured in 78 PCa, 22 benign prostatic hyperplasia, and 22 normal adjacent tissue samples using an AKAP12 methylation-sensitive high-resolution melting assay. AKAP12 gene expression was also examined in 4 human prostate carcinoma cell lines, PC-3, DU145, LNCaP, and 22RV1, using quantitative reverse transcriptase-polymerase chain reaction and methylation-sensitive high-resolution melting analysis and after DNA methyltransferase inhibition with 5-aza-2'-deoxycytidine. Methylation (>1%) of the AKAP12 promoter region was present in 47 (60.2%) of the 78 PCa, 5 (22.7%) of the 22 benign prostatic hyperplasia, and 2 (9.1%) of the 22 adjacent normal tissue samples. AKAP12 methylation was significantly greater in the PCa than in the benign prostatic hyperplasia or adjacent tissue samples (P < .01). AKAP12 methylation was significantly greater in the PCa samples with higher Gleason scores (P = .03); however, no correlation was found with age, pT category, or serum prostate-specific antigen level. Reverse transcriptase-polymerase chain reaction demonstrated that PC-3 and DU-145 cells expressed AKAP12 RNA and LNCaP and 22RV1 did not. The AKAP12 locus was methylated in the LNCaP and 22RV1 cells. Treatment of LNCaP cells with 5-aza-2'-deoxycytidine markedly decreased the methylation levels and increased the expression of AKAP12. The results of the present study have demonstrated that AKAP12 promoter methylation is a frequent event in human PCa. AKAP12 methylation represents a potential molecular biomarker for predicting the malignancy of PCa.

• Generation of pluripotent cancer-initiating cells from transformed bone marrow-derived cells.

  Authors: Chunfang Liu, Songtao Xu, Zhan Ma, Yu Zeng, Zhihong Chen, Yuan Lu

  Cancer letters. 02/2011; 303(2):140-9.

  Our previous studies indicated that pluripotent cancer-initiating cells existed in chemical carcinogen-transformed mouse bone marrow-derived cells (BMDCs). In this report, we named them as boneOur previous studies indicated that pluripotent cancer-initiating cells existed in chemical carcinogen-transformed mouse bone marrow-derived cells (BMDCs). In this report, we named them as bone marrow-derived pluripotent cancer-initiating (bmPCI) cells. The bmPCI cells showed properties of embryonal carcinoma (EC) cells/embryonic stem (ES) cells in morphology and gene expression, differentiated into multiple somatic tumor cells, generated oocyte-like cells and later developed into blastocyst-like structures in vitro while causing teratocarcinomas in vivo. These findings demonstrate that pluripotent cancer-initiating cells can originate from BMDCs. It provides an accessible in vitro model for copying the "embryonal rest" phenomenon from adult cells.

• Re-expression of AKAP12 inhibits progression and metastasis potential of colorectal carcinoma in vivo and in vitro.

  Authors: Weiwei Liu, Ming Guan, Tingting Hu, Xiaoye Gu, Yuan Lu

  PloS one. 01/2011; 6(8):e24015.

  AKAP12/Gravin (A kinase anchor protein 12) is one of the A-kinase scaffold proteins and a potential tumor suppressor gene in human primary cancers. Our recent study demonstrated the highly recurrentAKAP12/Gravin (A kinase anchor protein 12) is one of the A-kinase scaffold proteins and a potential tumor suppressor gene in human primary cancers. Our recent study demonstrated the highly recurrent loss of AKAP12 in colorectal cancer and AKAP12 reexpression inhibited proliferation and anchorage-independent growth in colorectal cancer cells, implicating AKAP12 in colorectal cancer pathogenesis. To evaluate the effect of this gene on the progression and metastasis of colorectal cancer, we examined the impact of overexpressing AKAP12 in the AKAP12-negative human colorectal cancer cell line LoVo, the single clone (LoVo-AKAP12) compared to mock-transfected cells (LoVo-CON). pCMV6-AKAP12-mediated AKAP12 re-expression induced apoptosis (3% to 12.7%, p<0.01), migration (89.6±7.5 cells to 31.0±4.1 cells, p<0.01) and invasion (82.7±5.2 cells to 24.7±3.3 cells, p<0.01) of LoVo cells in vitro compared to control cells. Nude mice injected with LoVo-AKAP12 cells had both significantly reduced tumor volume (p<0.01) and increased apoptosis compared to mice given AKAP12-CON. The quantitative human-specific Alu PCR analysis showed overexpression of AKAP12 suppressed the number of intravasated cells in vivo (p<0.01). These results demonstrate that AKAP12 may play an important role in tumor growth suppression and the survival of human colorectal cancer.

• Frequent hyperphosphorylation of AS160 in breast cancer.

  Authors: Xiao-Hua Jiang, Jian-Wen Sun, Ming Xu, Xiao-Fei Jiang, Chun-Fang Liu, Yuan Lu

  Cancer biology & therapy. 08/2010; 10(4):362-7.

  Enhanced cellular glucose uptake is a frequent characteristic of malignant cells. The Akt substrate of 160 kDa (AS160) is a newly discovered substrate for the protein kinase AKT and phosphorylationEnhanced cellular glucose uptake is a frequent characteristic of malignant cells. The Akt substrate of 160 kDa (AS160) is a newly discovered substrate for the protein kinase AKT and phosphorylation of AS160 (p-AS160) was recently recognized to play an important role in glucose transport. However, studies on AS160 in cancer do not yet exist. The aim of the present study was to investigate the p-AS160 level and its correlation with clinicopathological parameters and various biological markers in breast cancer. Results showed that in breast cancer, phosphorylation of AS160 at the key residue T642 was significantly (p < 0.001) higher than that in normal adjacent tissues. P-AS160 staining was positive in 75 of 81 cases (92.6%), including 32 with weak-(score 1), 31 with moderate-(score 2) and 12 with strong immunoreactivity (score 3). P-AS160 was inversely correlated with patient age (p = 0.041) and positively correlated with tumor size (p = 0.013) and the cell proliferation marker Ki-67 (MIB-1) (p < 0.001). This is the first study of AS160 in cancer. Our results show that AS160 phosphorylation level is frequently increased in breast cancer. These results implicate a possible role of AS160 in human breast tumorigenesis and suggest that p-AS160 might be useful as a marker and a potential novel treatment target for breast cancer.

• Quantitative assessment of AKAP12 promoter methylation in colorectal cancer using methylation-sensitive high resolution melting: Correlation with Duke's stage.

  Authors: Weiwei Liu, Ming Guan, Bing Su, Chuanzhong Ye, Ji Li, Xinju Zhang, Chunfang Liu, Min Li, Yong Lin, Yuan Lu

  Cancer biology & therapy. 06/2010; 9(11):862-71.

  The expression of AKAP12 (A Kinase anchoring protein 12) is markedly reduced in a variety of cancers. The purpose of this study was to establish a methylation-sensitive high resolution meltingThe expression of AKAP12 (A Kinase anchoring protein 12) is markedly reduced in a variety of cancers. The purpose of this study was to establish a methylation-sensitive high resolution melting (MS-HRM) assay for the quantitative detection of AKAP12 promoter methylation and expression and the association with clinicopathological variables in human colorectal cancer. We also assessed the effect of AKAP12 re-expression on cell growth and colony formation. Downregulation or loss of AKAP12 mRNA expression was detected in 31 of 45 tissue samples (68.9%). No significant correlation was observed between the reduced expression levels and patient age, gender, Duke's stage or tumor differentiation. Methylation (>1%) of the AKAP12 promoter region was present in 35 of 45 (77.8%) carcinoma tissue samples and 6 of 45 (13.3%) adjacent tissue samples. AKAP12 methylation was significantly higher in the colorectal cancer tissues exhibiting advanced Duke's stages. Treatment of the three colorectal carcinoma cell lines (LoVo, COLO320 and SW480) with completely methylated AKAP12 with inhibitors of DNA methyltransferase (5-Aza-2'-deoxycytidine) markedly increased expression of AKAP12 and decreased methylation levels. Ectopic expression of AKAP12 in the LoVo cell line suppressed cell growth and inhibited colony formation. The AKAP12 gene was examined by quantitative RT-PCR, MS-HRM analysis and bisulfite sequencing in 45 paired tissue samples obtained from primary colorectal carcinomas and the corresponding adjacent tissues. In addition, five colorectal carcinoma cell lines (LoVo, COLO205, SW480, LS174T and COLO320) were investigated and western blot analysis was used to investigate changes in protein expression. A proliferation assay and soft agar assay were performed after overexpression of AKAP12. Our study demonstrated that MS-HRM is a robust, fast and sensitive method for AKAP12 methylation analysis. AKAP12 methylation represents a potential molecular biomarker for predicting the malignancy of this cancer.

• Evaluation of the Sysmex UF-1000i for the diagnosis of urinary tract infection.

  Authors: Jie Wang, Ying Zhang, DongWen Xu, Weijun Shao, Yuan Lu

  American journal of clinical pathology. 04/2010; 133(4):577-82.

  Diagnosis of urinary tract infection (UTI) is primarily done by microbiologic culture, which is time-consuming and can produce false-positives and false-negatives. Flow cytometry allows for rapidDiagnosis of urinary tract infection (UTI) is primarily done by microbiologic culture, which is time-consuming and can produce false-positives and false-negatives. Flow cytometry allows for rapid screening of many samples and eliminates culturing. We analyzed the Sysmex UF-1000i (TOA Medical Electronics, Kobe, Japan) for accuracy in identifying RBCs and WBCs, casts, bacteria, and epithelia. We also evaluated its precision, linear estimation of results, carryover contamination rate, and anti-interference. UF-1000i agreement with manual counting was approximately 95% for RBCs and WBCs, epithelia, and casts. Its coefficient of variation for bacteria ranged from 4.7% to 15.2%. UF-1000i screening for UTIs exhibited great sensitivity (97%), specificity (79%), positive predictive value (70%), negative predictive value (99%), and accuracy (85%). The negative predictive value remained high even with complex UTI samples. The Sysmex UF-1000i shows great promise in excluding more than 50% of true-negative samples, improving detection efficiency, and reducing laboratory costs.

• Rapid determination of AKAP12 promoter methylation levels in peripheral blood using methylation-sensitive high resolution melting (MS-HRM) analysis: application in colorectal cancer.

  Authors: Weiwei Liu, Ming Guan, Bing Su, Ji Li, Weizhe Ma, Chunfang Liu, Min Li, Yong Lin, Yuan Lu

  Clinica chimica acta; international journal of clinical chemistry. 03/2010; 411(13-14):940-6.

  Colorectal cancer is the third most common form of cancer and hypermethylation has been shown to increase the risk of developing this disease. DNA hypermethylation in the A kinase anchor protein 12Colorectal cancer is the third most common form of cancer and hypermethylation has been shown to increase the risk of developing this disease. DNA hypermethylation in the A kinase anchor protein 12 (AKAP12/Gravin) promoter region and the accompanied underexpression of it has been noted in a variety of human cancers. We applied methylation-specific high resolution melting (MS-HRM) technology to detect quantitatively A kinase anchor protein 12 (AKAP12/Gravin) methylation in peripheral blood from 100 colorectal cancer patients and 50 healthy volunteers and in 3 colorectal cancer cell lines. In this study 48 of the 100 colorectal cancer samples (48%) were found to be methylated at the AKAP12 promoter region. AKAP12 methylation was significantly higher in the colorectal cancer samples with differentiation (p=0.03). We also compared the results generated by MS-HRM with a traditional methylation-specific PCR (MSP) assay. We found that intra-assay variability ranged from 6.14 to 9.90% and inter-assay variability ranged from 14.5 to 17.2%. The AKAP12 MS-HRM assay was able to reproducibly detect 1% methylated DNA, whereas the MSP method was unable to detect less than 5% methylation. We demonstrate the utility of quantitative AKAP12 MS-HRM analysis of promoter methylation in peripheral blood samples. AKAP12 MS-HRM quantitative methods with excellent detection capabilities have many promising applications in the research and diagnosis of colorectal cancer.

• The pheV Phenylalanine tRNA Gene in Klebsiella pneumoniae Clinical Isolates Is an Integration Hotspot for Possible Niche-Adaptation Genomic Islands.

  Authors: Nan Chen, Hong-Yu Ou, Jon van Aartsen, Xiaofei Jiang, Min Li, Zehua Yang, Quhao Wei, Xiaoyun Chen, Xinyi He, Zixin Deng, Kumar Rajakumar, Yuan Lu

  Current microbiology. 11/2009;

  Horizontally acquired genomic islands may allow bacteria to conquer and colonize previously uncharted niches. Four Klebsiella pneumoniae tRNA gene insertion hotspots (arg6, asn34, met56, and pheV) inHorizontally acquired genomic islands may allow bacteria to conquer and colonize previously uncharted niches. Four Klebsiella pneumoniae tRNA gene insertion hotspots (arg6, asn34, met56, and pheV) in 101 clinical isolates derived from blood, sputum, wound, bile or urine specimens were screened by long-range PCR for the presence or absence of integrated islands. The pheV phenylalanine tRNA gene was the most frequently occupied site and harbored at least three entirely distinct types of islands: (1) KpGI-1, a 3.7 kb island coding for four proteins, three of which showed high similarity to two hypothetical proteins and a Gcn5-related N-acetyltransferase in Salmonella enterica, (2) KpGI-2, a 6.4 kb island coding for five proteins including a truncated phage-like integrase, two helicase-related proteins, and a homolog of the functionally elusive Fic protein, and (3) KpGI-3, a 12.6 kb island which carried seven fimbriae-related genes, first identified in MGH78578. Consistent with the niche-adaptation hypothesis, KpGI-1-like islands which coded for the putative acetyltransferase were significantly over-represented in sputum isolates as compared to urine (P < 0.001), blood (P < 0.05) or bile (P < 0.05) derived isolates. Despite the unique nature of KpGI-2, likely homologs of orf5_KpGI-2 that coded for Fic were also found at undefined locations in six other clinical isolates, though none possessed the other KpGI-2 genes. We propose that the pheV-associated islands described in this study may contribute to fine tuning and adaptation of K. pneumoniae strains toward preferred infection and/or colonization pathways.

• Molecular characterization of Staphylococcus epidermidis strains isolated from a teaching hospital in Shanghai, China.

  Authors: Min Li, Xing Wang, Qian Gao, Yuan Lu

  Journal of medical microbiology. 05/2009; 58(Pt 4):456-61.

  Staphylococcus epidermidis is a leading cause of hospital-acquired infections, mostly associated with the use of medical devices in seriously ill or immunocompromised patients. Currently, the clonalStaphylococcus epidermidis is a leading cause of hospital-acquired infections, mostly associated with the use of medical devices in seriously ill or immunocompromised patients. Currently, the clonal characteristics of S. epidermidis in the hospital environment in China are unknown; neither is it known why these sequence types are easily disseminated in the hospital setting. In this study, multilocus sequence typing (MLST) was employed for the clonal analysis of 80 S. epidermidis isolates collected from patients with S. epidermidis infections. MLST revealed a total of 16 different sequence types among these isolates. ST2, which contained exclusively ica-positive, IS256-positive and biofilm-forming isolates, represented the majority of clinical strains tested. Of the S. epidermidis strains circulating in the hospital environment in China, as many as 96.25 % are resistant to meticillin. Four staphylococcal chromosomal cassette mec (SCCmec) types were identified among the total 80 S. epidermidis isolates, none of the strains carried an SCCmec I cassette. All of the ST2 isolates carried the SCCmec type III cassette. Taken together, the combination of biofilm-forming ability and antibiotic resistance helps ST2 become successfully established within nosocomial environments, and promotes the device-related infection and bacteraemia.

• Overexpression of DLC-1 induces cell apoptosis and proliferation inhibition in the renal cell carcinoma.

  Authors: Tao Zhang, Jingcun Zheng, Ning Jiang, Guozeng Wang, Quan Shi, Chunfang Liu, Yuan Lu

  Cancer letters. 05/2009;

  The lack of effective anti-tumor therapy for renal cell carcinoma (RCC) has stimulated the search for novel target whose inhibition could block tumorigenesis. Recently, reduced DLC-1 has been shownThe lack of effective anti-tumor therapy for renal cell carcinoma (RCC) has stimulated the search for novel target whose inhibition could block tumorigenesis. Recently, reduced DLC-1 has been shown to be associated with aggressive and highly metastatic renal cell carcinoma. In this study, the biological role of DLC-1 on cell growth, migration and cell cycle progression in RCC cells was investigated. Over-expression of DLC-1 was associated with a marked inhibition of cell growth (P<0.01). The inhibitory effect was partly due to the induction of apoptosis and cell cycle arrest in G(0)/G(1) accompanied by up-regulation of the intracellular signal proteins of p27 and down-regulation of cyclin D1 and cyclin E. Furthermore, DLC-1 induced FAK dephosphorylation of focal adhesion proteins inhibited cell migration (P<0.05). Decreased DLC-1 expression strongly correlated with proliferative activity, as indicated by the elevated levels of Ki67. Restoration of DLC-1 expression in RCC cells led to Bcl-2 and caspase-3 mediated apoptosis as well as attenuated the ability of the cells to form RCC tumors in athymic nude mice (P<0.05). Taken together, these results suggest that DLC-1 plays a crucial role in signal transduction pathway regulating the cell proliferation, migration, and carcinogenesis of human RCC.

• cDNA microarray analysis of pigment epithelium-derived factor-regulated gene expression profile in prostate carcinoma cells.

  Authors: Weiwei Liu, Zhong Wu, Ming Guan, Yuan Lu

  International journal of urology : official journal of the Japanese Urological Association. 02/2009;

  Objectives: To clarify molecular mechanisms involved in the action of pigment epithelium-derived factor (PEDF) in hormone insensitive prostate cancer cells. Methods: Total ribonucleic acid fromObjectives: To clarify molecular mechanisms involved in the action of pigment epithelium-derived factor (PEDF) in hormone insensitive prostate cancer cells. Methods: Total ribonucleic acid from untreated and PEDF-treated cells was subjected to microarray analysis using BioStar 8464 microarray. Real-time polymerase chain reaction analysis was conducted to confirm the microarray data. Results: Twenty-seven out of 8464 genes were found altered in both cell lines. Common gene responses altered by PEDF were identified and included genes known to alter cell signaling as well as genes involved in catalytic activity, cell proliferation, angiogenesis and apoptosis. Real-time reverse transcription polymerase chain reaction, in accordance with the microarray analysis, indicated that PEDF treatment caused an upregulation in the mRNA expression level of stanniocalcin 2, brain-specific angiogenesis inhibitor 2 and growth arrest, DNA-damage-inducible, alpha, and downregulation in the messenger ribonucleic acid level of fibroblast growth factor 3, teratocarcinoma-derived growth factor, neuropilin1, and endothelial Per/ARNT/Sim domain protein1, respectively. Conclusions: These findings demonstrate that PEDF administration causes significant changes in the gene expression of the prostate, providing insights into the potential role of PEDF in the treatment of prostate cancer.

• Expression of DLC-1 in clear cell renal cell carcinoma: prognostic significance for progression and metastasis.

  Authors: Tao Zhang, Jingcun Zheng, Chunfang Liu, Yuan Lu

  Urologia internationalis. 01/2009; 82(4):380-7.

  INTRODUCTION: Metastatic renal cell carcinoma (RCC) remains the leading cause of mortality in patients with clear cell RCC. While deleted in liver cancer (DLC-1) is known to be closely associatedINTRODUCTION: Metastatic renal cell carcinoma (RCC) remains the leading cause of mortality in patients with clear cell RCC. While deleted in liver cancer (DLC-1) is known to be closely associated with tumor growth and metastasis in several kinds of human tumors, the function of DLC-1 in clear cell RCC is unclear. MATERIALS AND METHODS: We quantified DLC-1 mRNA expression in paired tumor and non-tumor samples from 62 patients in clear cell RCC using a real-time reverse transcription polymerase chain reaction (RT-PCR), and DLC-1 protein using Western blotting and immunohistochemistry. The association between DLC-1 and matrix metalloproteinase-2 were analyzed. RESULTS: A high level of DLC-1 mRNA and protein expression in approximately 90% of normal renal specimens, the expression levels of DLC-1 in the primary tumors with synchronous metastases were lower than in those without metastases (p < 0.01). Furthermore, DLC-1 expression inversely correlated with advanced histological grade and stage (p < 0.05). Moreover, it is likely that down-regulated DLC-1 increases matrix invasion abilities of RCC via enhancing matrix metalloproteinase-2 expression. CONCLUSION: Together, it seems that reduced DLC-1 is involved in tumor expansion phenomena associated with tumor progression, invasion and distant metastasis of RCC.

• dfrA27, a new integron-associated trimethoprim resistance gene from Escherichia coli.

  Authors: Quhao Wei, Xiaofei Jiang, Zehua Yang, Nan Chen, Xiaoyun Chen, Gang Li, Yuan Lu

  The Journal of antimicrobial chemotherapy. 12/2008;

• Frequent mutations and amplifications of the PIK3CA gene in pituitary tumors.

  Authors: Yong Lin, Xiaofei Jiang, Ye Shen, Min Li, Huili Ma, Michael Xing, Yuan Lu

  Endocrine-related cancer. 10/2008;

  Genetic alterations in the PIK3CA gene of the phosphoinositide 3-kinase (PI3K)/AKT pathway have been found in many human tumors, but they have not been explored in pituitary tumors. We undertook theGenetic alterations in the PIK3CA gene of the phosphoinositide 3-kinase (PI3K)/AKT pathway have been found in many human tumors, but they have not been explored in pituitary tumors. We undertook the present study to explore mutations and amplifications of the PIK3CA gene in pituitary tumors. DNA sequencing and real-time quantitative PCR were used to examine mutations and amplifications, respectively, on genomic DNA samples isolated from 353 cases of pituitary tumors, and immunohistostaining was used to assess PIK3CA expression. Eight of 91 (9%) invasive pituitary tumors vs. 0 of 262 (0%) non-invasive tumors were found to harbor somatic mutations in exons 9 and 20 of the PIK3CA gene (P<0.001), and the mutation was associated with increased disease recurrence. Genomic PIK3CA amplifications (defined as > 4 copies) were observed in both invasive and noninvasive tumors, with a prevalence of around 20-40% in various types of pituitary tumors. PIK3CA protein overexpression was observed in cases with high PIK3CA copy number. Ras mutations were also examined and found in 6 of 91 (7%) invasive tumors. PIK3CA amplifications were mutually exclusive with PIK3CA or Ras mutations (P<0.001). This study demonstrated for the first time relatively common PIK3CA mutations and amplifications as well as Ras mutations and their tendency of mutual exclusivity in pituitary tumors. The data provide strong genetic evidence supporting a role of the PI3K/AKT signaling pathway in the tumorigenesis of pituitary tumors, particularly the invasive types.

• A novel and rapid method for determining integration frequency catalyzed by integron integrase intI1.

  Authors: Zehua Yang, Xiaofei Jiang, Quhao Wei, Nan Chen, Yuan Lu

  Journal of microbiological methods. 10/2008;

  We developed a faster and more convenient method to determine integration frequency mediated by integron integrase intI1. This method based on real-time fluorescent quantitative PCR. By using thisWe developed a faster and more convenient method to determine integration frequency mediated by integron integrase intI1. This method based on real-time fluorescent quantitative PCR. By using this method, we revealed that the integration frequency of aadA2 gene cassette was 1.87x10(-4) when integrase intI1 was present, and the background frequency was less than 5.23x10(-8) without integrase intI1.

• Pigment epithelium-derived factor inhibits glioma cell growth in vitro and in vivo.

  Authors: Tao Zhang, Ming Guan, Chong Xu, Yuming Chen, Yuan Lu

  Life sciences. 10/2007; 81(16):1256-63.

  Glioblastoma multiforme is the most common malignant brain tumor in adults, and it is among the most lethal of all cancers. Recent studies have shown that pigment epithelium-derived factor (PEDF) canGlioblastoma multiforme is the most common malignant brain tumor in adults, and it is among the most lethal of all cancers. Recent studies have shown that pigment epithelium-derived factor (PEDF) can induce differentiation and inhibit angiogenesis of several tumors. This study was designed to determine whether gliomas angiogenesis and tumor growth could be inhibited by PEDF. We found that PEDF down-regulated expression levels of vascular endothelial growth factor and up-regulated the expression of thrombospondin-2 and augmented apoptosis in a dose-dependent manner in both A172 and U87 glioma cells lines after 48 h of treatment. Analysis of the cell cycle showed arrest in the G(1) phase and block in S phase of the cell cycle. Meanwhile PEDF induced apoptosis was associated with increases of p53 and Bax and inhibition of Bcl-2. Conditioned medium with PEDF showed a significantly reductive effect on migration in vitro accompanied with a significant reduction of matrix metalloproteinase-9 expression. PEDF suppressed glioma cell migration in vitro and tumor burden in athymic nude mice. These results demonstrate for the first time inhibitory effects of PEDF on the growth and migration of human gliomas via induction of apoptosis and blocking of migratory-related factors. PEDF activation can be a novel approach for future therapeutic purposes against gliomas.

• Adenovirus-mediated PEDF expression inhibits prostate cancer cell growth and results in augmented expression of PAI-2.

  Authors: Ming Guan, Haowen Jiang, Chong Xu, Rong Xu, Zhongqing Chen, Yuan Lu

  Cancer biology & therapy. 04/2007; 6(3):419-25.

  PEDF is one of the most potent inhibitor of angiogenesis. Loss of PEDF was found in human prostate tumors and associated with the progression toward a metastatic phenotype. To test the therapeuticPEDF is one of the most potent inhibitor of angiogenesis. Loss of PEDF was found in human prostate tumors and associated with the progression toward a metastatic phenotype. To test the therapeutic potential of PEDF, we constructed a replication-defective adenoviral vector capable of efficient transduction and expression of PEDF (Ad-PEDF) in PC-3 prostate carcinoma cells. As controls, we used adenoviruses expressing beta-galactosidase (Ad-LacZ). We showed that overexpression of PEDF inhibited proliferation of cells and augmented apoptosis in serum-starved cells, in comparison with Ad-LacZ. Furthermore, Ad-PEDF suppresses anchorage-independent growth cells in soft agar and tumor formation in athymic nude mice associated with decreased microvessel density. Microarray analysis showed that 56 out of 8464 genes were found to be upregulated and downregulated in the PC-3 infected with Ad-PEDF as compared with Ad-LacZ. The differentially expressed genes cover a broad range of functional activities including catalytic activity, protein binding, signal transduction activity and cell invasion. Among them, PAI-2 and DRHC were confirmed to be upregulated with real-time PCR and Western blot, suggesting a possible association with PEDF-induced signaling for cell motility and metastasis. These results can contribute to our understanding of the molecular mechanisms of treatment strategies of PEDF for prostate cancer.

• Detection of extended-spectrum beta-lactamases in clinical isolates of Pseudomonas aeruginosa.

  Authors: Xiaofei Jiang, Zhe Zhang, Min Li, Danqiu Zhou, Feiyi Ruan, Yuan Lu

  Antimicrobial agents and chemotherapy. 10/2006; 50(9):2990-5.

  With the occurrence of extended-spectrum beta-lactamases (ESBLs) in Pseudomonas aeruginosa being increasingly reported worldwide, there is a need for a reliable test to detect ESBLs in clinicalWith the occurrence of extended-spectrum beta-lactamases (ESBLs) in Pseudomonas aeruginosa being increasingly reported worldwide, there is a need for a reliable test to detect ESBLs in clinical isolates of P. aeruginosa. In our study, a total of 75 clinical isolates of P. aeruginosa were studied. Nitrocefin tests were performed to detect the beta-lactamase enzyme; isoelectric focusing electrophoresis, PCR, and PCR product sequencing were designed to further characterize the contained ESBLs. Various ESBL-screening methods were designed to compare the reliabilities of detecting ESBLs in clinical isolates of P. aeruginosa whose beta-lactamases were well characterized. Thirty-four of 36 multidrug-resistant P. aeruginosa clinical isolates were positive for ESBLs. bla(VEB-3) was the most prevalent ESBL gene in P. aeruginosa in our study. Among the total of 34 isolates that were considered ESBL producers, 20 strains were positive using conventional combined disk tests and 10 strains were positive using a conventional double-disk synergy test (DDST) with amoxicillin-clavulanate, expanded-spectrum cephalosporins, aztreonam, and cefepime. Modifications of the combined disk test and DDST, which consisted of shorter distances between disks (20 mm instead of 30 mm) and the use of three different plates that contained cloxacillin (200 microg/ml) alone, Phe-Arg beta-naphthylamide dihydrochloride (MC-207,110; 20 microg/ml) alone, and both cloxacillin (200 microg/ml) and MC-207,110 (20 microg/ml) increased the sensitivity of the tests to 78.8%, 91.18%, 85.29%, and 97.06%.