Therapeutic potential of PRL-3 targeting and clinical significance of PRL-3 genomic amplification in gastric cancer

<p>Abstract</p> <p>Background</p> <p>Phosphatase of regenerating liver-3 (PRL-3) has deserved attention as a crucial molecule in the multiple steps of metastasis. In the present study, we examined the mechanisms regulating PRL-3 expression, and assessed the clinical potential of PRL-3-targeted therapy in gastric cancer.</p> <p>Methods</p> <p>PRL-3 genomic amplification was analyzed using quantitative-polymerase chain reaction and/or fluorescence in situ hybridization in 77 primary gastric tumors. The anticancer activity of PRL-3 inhibitor (1-4-bromo-2-benzylidene rhodanine) treatment was evaluated against cancer cells with different genetic and expression status.</p> <p>Results</p> <p>PRL-3 genomic amplification was closely concordant with high level of its protein expression in cell lines, and was found in 20% (8/40) among human primary tumors with its expression, which were all stage III/IV disease (40%, 8/20), but in none (0/37) among those without expression. Additionally, PRL-3 genomic amplification was associated with metastatic lymph node status, leading to advanced stage and thereby poor outcomes in patients with lymph node metastasis (<it>P </it>= 0.021). PRL-3 small interfering RNA robustly repressed metastatic properties, including cell proliferation, invasion, and anchorage-independent colony formation. Although neither PRL-3 genomic amplification nor expression level was responsible for the sensitivity to PRL-3 inhibitor treatment, the inhibitor showed dose-dependent anticancer efficacy, and remarkably induced apoptosis on all the tested cell lines with PRL-3 expression.</p> <p>Conclusions</p> <p>We have for the first time, demonstrated that PRL-3 genomic amplification is one of the predominant mechanisms inducing its expression, especially in more advanced stage, and that PRL-3-targeted therapy may have a great potential against gastric cancer with its expression.</p

Genomic dissection of the Vibrio cholerae O-serogroup global reference strains: reassessing our view of diversity and plasticity between two chromosomes

Approximately 200 O-serogroups of Vibrio cholerae have already been identified; however, only 2 serogroups, O1 and O139, are strongly related to pandemic cholera. The study of non-O1 and non-O139 strains has hitherto been limited. Nevertheless, there are other clinically and epidemiologically important serogroups causing outbreaks with cholera-like disease. Here, we report a comprehensive genome analysis of the whole set of V. cholerae O-serogroup reference strains to provide an overview of this important bacterial pathogen. It revealed structural diversity of the O-antigen biosynthesis gene clusters located at specific loci on chromosome 1 and 16 pairs of strains with almost identical O-antigen biosynthetic gene clusters but differing in serological patterns. This might be due to the presence of O-antigen biosynthesis-related genes at secondary loci on chromosome 2

Enhancement of Murine Tumor Cell Lysability by Interleukin-2 Activated Killer Cells After Treatment with Mitomycin C

The cytotoxicity of interleukin-2 activated killer cells with antitumor drug, mitomycin C (MMC) against murine tumor cell lines with acquired drug resis-tance was evaluated in vitro by a 51Cr release cytotoxicity assay. Tumor cell lines, a mouse fibrosarcoma cells (MCA-F) and its individual metastatic lung clones (MCA-F-M1, 2, 3, and 4) have been established in vitro. Furthermore, using a soft agar cloning technique, MMC resistant clones (MCA-F-M2-1, 2, 4, 8, and 10) and sensitive clones (MCA-F-M1-3, MCA-F-M3-8, 9, MCA-F-M4-9, and 10) were established and their lysability was examined with or without MMC against lymphokine-activated killer (LAK) cells, demonstrating that LAK cells showed high % cytotoxicity against 2 resistant clones (MCA-F-M2-1 and 8) by the 7 day-exposure of 1.0 pg/ml MMC concentration in culture but with a low % cytotoxicity in the case of only 3 day-MMC exposure. The other resis-tant clones showed high % cytotoxicity at 3 day-MMC exposure. On the other hand, all the sensitive clones showed high % cytotoxicity against LAK cells with the only 1 day-exposure of MMC. Thus, the combination of LAK cells and MMC treatment had a synergistic effect on MMC resistant clones as well as sensitive clones and these results suggested that the lysability of MMC resistant clones might be due to the altered susceptibility to LAK cells by use of MMC time-dependently

Antitumor Activity of Activated Lymphocytes and Macrophages by Liposome-borne Tumor-specific Transplantation Antigens on Postsurgical Tumor Recurrence in Murine

Liposome-borne tumor-specific transplantation antigens (TSTA) potentiated the antitumor activity of cytotoxic lymphocytes and macrophages (Mφ) much more efficiently than empty liposomes in murine. Mφ obtained from peritoneum and lung as well as cytotoxic T-lymphocytes (CTL) such as lymphokine-activat-ed killer (LAIC) cells and tumor infiltrating lymphocytes (TIL) showed higher inhibitory activity on metastatic tumor cell growth in lung. Among the effector lymphocytes in vivo, TIL showed desiable antitumor activity by way of intra-venous injection, while peritoneal Mφ showed high cytotoxicity by intraper-itoneal injection and intraveneously alveolar Mφ also showed high cytotoxic activity. These results suggest that the suitable administrations of liposome-borne TSTA may be useful in potentiating the tumoricidal effect of effector cells in vivo, especially TIL, CTL, and Mφ, and possibly may aid in overcoming tumor metastases

Detection of p53 Gene Mutations and Their Protein Overexpression in Fine-needle Biopsy Specimens with False-negative Diagnoses in Breast Cancer

To achieve a more accurate diagnosis in the first aspiration biopsy from breast tumor, p53 gene mutations were detected by PCR-SSCP analysis in aspira-tion biopsy specimens taken from 26 patients with breast tumors. Of 26 aspirat-ed cell specimens from breast tumors that were all initially diagnosed as being cytologically benign, 2 point mutations of the p53 gene were detected and were subsequently proved to be cancer cells. Further, the p53 protein expression was also examined in the initial aspirated specimens and in the resected tumors that were rediagnosed as being malignant as a result of the second biopsy. Conse-quently, these p53 gene mutations did not appear to correlate with their protein overexpression in the aspiration biopsy specimens (all cases were negative), how-ever, the specimens from 2 resected tumors that showed p53 gene mutations were positive. In addition, a positive ER level and DNA aneuploidy status were also found only in these two p53 gene mutation cases. Therefore, detection of p53 mutations in aspiration biopsy specimens may prove to be a useful method for detecting breast cancers

Protein kinase C (Pkc)-δ mediates arginine-induced glucagon secretion in pancreatic α-cells

The pathophysiology of type 2 diabetes involves insulin and glucagon. Protein kinase C (Pkc)-δ, a serine-threonine kinase, is ubiquitously expressed and involved in regulating cell death and proliferation. However, the role of Pkcδ in regulating glucagon secretion in pancreatic α-cells remains unclear. Therefore, this study aimed to elucidate the physiological role of Pkcδ in glucagon secretion from pancreatic α-cells. Glucagon secretions were investigated in Pkcδ-knockdown InR1G9 cells and pancreatic α-cell-specific Pkcδ-knockout (αPkcδKO) mice. Knockdown of Pkcδ in the glucagon-secreting cell line InR1G9 cells reduced glucagon secretion. The basic amino acid arginine enhances glucagon secretion via voltage-dependent calcium channels (VDCC). Furthermore, we showed that arginine increased Pkcδ phosphorylation at Th

Biology and genome of a newly discovered sibling species of Caenorhabditis elegans

A ‘sibling’ species of the model organism Caenorhabditis elegans has long been sought for use in comparative analyses that would enable deep evolutionary interpretations of biological phenomena. Here, we describe the first sibling species of C. elegans, C. inopinata n. sp., isolated from fig syconia in Okinawa, Japan. We investigate the morphology, developmental processes and behaviour of C. inopinata, which differ significantly from those of C. elegans. The 123-Mb C. inopinata genome was sequenced and assembled into six nuclear chromosomes, allowing delineation of Caenorhabditis genome evolution and revealing unique characteristics, such as highly expanded transposable elements that might have contributed to the genome evolution of C. inopinata. In addition, C. inopinata exhibits massive gene losses in chemoreceptor gene families, which could be correlated with its limited habitat area. We have developed genetic and molecular techniques for C. inopinata; thus C. inopinata provides an exciting new platform for comparative evolutionary studies