Discovery of NKCC1 as a potential therapeutic target to inhibit hepatocellular carcinoma cell growth and metastasis.

Metastasis is the essential cause for the high mortality of hepatocellular carcinoma (HCC). In order to investigate the mechanism of metastasis, and to discover therapeutic targets for HCC, the quantitative proteomic technique was applied to characterize the plasma membrane proteins of two HCC cell lines with low (MHCC97L) or high (MHCC97H) metastatic potentials. One of the plasma membrane proteins, sodium-potassium-chloride cotransporter 1 (NKCC1), was upregulated in MHCC97H cell line. Immunohistochemistry result in HCC patients showed that NKCC1 expression was associated with poor differentiation and microvascular invasion. Knockdown of NKCC1 via RNA interference reduced HCC cell proliferation and invasion abilities in vitro and in vivo, whereas over-expression of NKCC1 significantly increased HCC cell proliferation and invasion abilities in vitro and in vivo. Additionally, blocking NKCC1 activity with bumetanide attenuated the proliferation and invasion abilities of HCC cells in vitro and limited the HCC growth in vivo. Further results suggested that NKCC1 promotes the invasion ability via MMP-2 activity, and that the WNK1/OSR1/NKCC1 signal pathway might play roles in HCC metastasis. For the first time, our study demonstrated that NKCC1 plays a role in HCC metastasis, and could be served as a potential target to inhibit HCC cell growth and metastasis.

Differential Diagnosis of Candida Species With Real-Time Polymerase Chain Reaction and Melting Temperature Analyses (RTPCR-MTA).

Genus Candida covers more than 50 species, half of which can cause infections in humans. Some of the Candida species exhibit drug resistance; therefore, there is an urgent need for rapid and accurate differentiation for rendering appropriate and effective management. Here, we report a new methodology employing real-time polymerase chain reaction (RTPCR) and melting temperature analyses (MTA) procedures. Fungal ribosomal internal transcribed spacer 2 (ITS2) has been confirmed with variable nucleotide sequences, which makes it possible to differentiate one species from another by checking their melting temperature following PCR amplification. The universal primers (panFg) covering entire ITS2 region, from 5.8S to 28S rRNA genes, were designed to differentially identify most Candida species with RTPCR-MTA procedure. Nucleic acids from five genomes of closely related Candida species, which were experimentally spiked into human blood, were extracted and amplified. PCR amplicons were called for melting temperature of Candida albicans (87.49°C), C. glabrata (86.85°C), C. krusei (90.24°C), C. parapsilosis (86.22°C), and C. tropicalis (86.08°C). The melting temperature of each amplicon was consistent and reproducible in three replicate experiments (SD ± 0.04-0.32). The new RTPCR-MTA methodology showed promise in differential diagnosis of closely related Candida species from environmental and clinical samples.

Pseudomonas aeruginosa induces pigment production and enhances virulence in a white phenotypic variant of Staphylococcus aureus.

Staphyloxanthin is a virulence factor which protects Staphylococcus aureus in stress conditions. We isolated two pigment variants of S. aureus and one strain of Pseudomonas aeruginosa from a single wound infection. S. aureus variants displayed white and yellow colony phenotypes. The sequence of the operons for staphyloxanthin synthesis indicated that coding and promoter regions were identical between the two pigment variants. Quorum sensing controls pigment synthesis in some bacteria. It is also shown that P. aeruginosa quorum-sensing molecules affect S. aureus transcription. We explored whether the co-infecting P. aeruginosa can affect pigment production in the white S. aureus variant. In co-culture experiments between the white variants and a selected number of Gram-positive and Gram-negative bacteria, only P. aeruginosa induced pigment production in the white variant. Gene expression analysis of the white variant did not indicate upregulation of the crtM and other genes known to be involved in pigment production (sigB, sarA, farnesyl pyrophosphate synthase gene [FPP-synthase], hfq). In contrast, transcription of the catalase gene was significantly upregulated after co-culture. P. aeruginosa-induced pigment synthesis and catalase upregulation correlated with increased resistance to polymyxin B, hydrogen peroxide, and the intracellular environment of macrophages. Our data indicate the presence of silent but functional staphyloxanthin synthesis machinery in a white phenotypic variant of S. aureus which is activated by a co-infecting P. aeruginosa via inter-species communication. Another S. aureus virulence factor, catalase is also induced by this co-infecting bacterium. The resulting phenotypic changes are directly correlated with resistance of the white variant to stressful conditions.

Splenic manifestations of chronic autoimmune disorder: a report of five cases with histiocytic necrotizing change in four cases.

AIMS: Autoimmune diseases (AD) are associated with lymphadenopathy and splenomegaly. Changes in the spleen have not been characterized completely in AD; we describe splenectomy specimens from five patients with chronic AD, highlighting the presence of necrotizing histiocytosis. METHODS AND RESULTS: Of the patients (three males and two females; mean 40 years), four had systemic lupus erythematosus; one had rheumatoid arthritis. All had moderate splenomegaly (213-803 g, mean 421 g). Four cases exhibited necrosis with apoptosis and karyorrhectic debris occurring in the white pulp and minimal acute inflammation; one showed florid follicular hyperplasia. Splenic involvement ranged from focal to extensive. Plasma cells were negative for IgG4. Haematoxylin bodies were not identified. Stains for infectious organisms were negative. Immunohistochemical studies showed that lymphocytes surrounding the necrosis were a mixture of CD4(+) and CD8(+) T cells; CD123-positive plasmacytoid dendritic cells were not present, and staining for kappa and lambda light chains showed no clonality. 16S rDNA PCR was performed; no amplification was seen in three of four cases tested for bacteria specific rDNA. Epstein-Barr virus-encoded RNA (EBER) in situ hybridization studies highlighted rare positive cells in four cases. CONCLUSIONS: Splenomegaly in AD is thought to be hyperplasic, but we present four cases showing histiocytic necrosis, a finding which should be considered part of the spectrum of AD in the spleen.

Sequential real-time PCR assays applied to identification of genomic signatures in formalin-fixed paraffin-embedded tissues: a case report about brucella-induced osteomyelitis.

Brucellosis is a zoonotic infection transmitted from animals to human by ingestion of infected food products, direct contact with an infected animal, or inhalation of aerosols. Brucella infection-induced osteomyelitis may present only with nonspecific clinical and radiographic findings, mild elevations in serum inflammatory markers, as well as nonspecific histological changes. We studied a case of an Iraqi war veteran with multifocal vertebral body and left iliac bone lesions on radio nucleotide scans and magnetic resonance imaging, clinically suspected osteomyelitis possibly because of Brucella. Although histomorphological findings were nonspecific, consisting of chronic inflammatory cell infiltrate and reactive fibrosis, tissue gram and silver impregnation stains of bone biopsies were informative, revealing gram-negative coccobacilli consistent in size with Brucella species. Total nucleic acids were extracted from formalin-fixed paraffin-embedded tissues and amplified by sequential real-time polymerase chain reaction, targeting genes coding (1) outer membrane protein (omp-31) of Brucella species and (2) insertion sequence (IS711) of Brucella abortus (b-abt). Polymerase chain reaction results confirmed B. abortus as the causative pathogens for presumed diagnosis of Brucella osteomyelitis.

Development of hydrolysis probe-based real-time PCR for identification of virulent gene targets of Burkholderia pseudomallei and B. mallei--a retrospective study on archival cases of service members with melioidosis and glanders.

Burkholderia pseudomallei and B. mallei are two highly pathogenic bacteria responsible for melioidosis and glanders, respectively. Our laboratory developed hydrolysis probe-based real-time polymerase chain reaction assays targeting type three secretion system (TTS) and transposase family protein (TFP) of B. pseudomallei and B. malli, respectively. The assays were validated for target specificity, amplification sensitivity, and reproducibility. A bacterial DNA panel, composed of B. pseudomallei (13 strains), B. mallei (11 strains), Burkholderia species close neighbors (5 strains), and other bacterial species (17 strains), was prepared for specificity testing. Reference DNAs from B. pseudomallei and B. mallei bacterial cultures were used as controls for amplification, limit of detection, and reproducibility testing. The two TaqMan assays, Bp-TTS 1 and Bm-TFP, were optimized and applied in a retrospective study of archived cases from the Armed Forces Institute of Pathology. We tested 10 formalin-fixed paraffin-embedded blocks originally from autopsy specimens of patients who died of melioidosis or glanders during or after overseas tours in 1960s. Polymerase chain reaction results confirmed that DNA samples from formalin-fixed paraffin-embedded blocks of eight patients with melioidosis were positive for Bp-TTS 1 target and two patients with glanders were positive for Bm-TFP target.

Medulloblastoma and Brucellosis - Molecular Evidence of Brucella sp in Association with Central Nervous System Cancer.

Neurobrucellosis has been reported to cause lesions in a number of different locations in the central nervous system. Histologically or radiologically, these lesions were consistent with an infection. In response to parents who believed their child's brain tumor, histologically typical of medulloblastoma, was in reality neurobrucellosis, formalin-fixed paraffin-embedded tumor tissue from the medulloblastoma was sectioned, DNA extracted, and tested by polymerase chain reaction (PCR). Specific primer/probe sets, designed in our laboratory to target Brucella species, B. melitensis, B. abortus and B. suis, and designated OMP31, B-m, B-a and B-s, respectively, were used in TaqMan real-time PCR to amplify those gene targets in two separate blocks of the child's tumor. Sections from two blocks were positive only for Brucella species. Although the patient grew up in a European country known to harbor brucella in foods, such as unpasturized milk and cheese, the patient was seronegative for B. mellitensis, B. suis, and B. abortus. In an effort to test whether a relationship existed between the presence of brucella and medulloblastoma, 20 medulloblastomas were retrieved from the tissue repository of the AFIP. The above four primer/probe sets were again used to amplify brucella DNA. Five of 20 tumors (25%) contained Brucella species DNA by the OMP31 primer/probe set. None of the 20 medulloblastomas had specific sequences for B. mellitensis, B. suis, or B. abortus. Is chronic brucellosis similar to other infectious agents such as helicobacter that is associated with tumor formation?