Expression of Functional Anti-p24 scFv 183-H12-5C in HEK293T and Jurkat T Cells

Purpose: More than half of the diagnostic and therapeutic recombinant protein production depends on mammalian-based expression system. However, the generation of recombinant antibodies remains a challenge in mammalian cells due to the disulfide bond formation and reducing cytoplasm. Therefore, the production of functional recombinant antibodies in target cell line is necessary to be evaluated before used in therapeutic application such intrabodies against HIV-1. Methods: The work was to test expression of a single-chain variable fragment (scFv) antibody against HIV-1 Capsid p24 protein in a human mammalian-based expression system using HEK293T and Jurkat T cells as a model. Three expression plasmid vectors expressing scFv 183-H12-5C were generated and introduced into HEK293T. Expression of the scFv was analyzed, while ELISA and immunoblotting analysis verified its binding. The evaluation of the recombinant antibody was confirmed by HIV-1 replication and MAGI infectivity assay in Jurkat T cells. Results: Three plasmid vectors expressing scFv 183-H12-5C was successfully engineered in this study. Recombinant antibodies scFv (~29 kDa) and scFv-Fc (~52 kDa) in the cytoplasm of HEK293T were effectively obtained by transfected the cells with engineered pCDNA3.3-mu-IgGk-scFv 183-H12-5C and pCMX2.5-scFv 183-H12-5C-hIgG1-Fc plasmid vectors respectively. scFv and scFv-Fc are specifically bound recombinant p24, and HIV-1 derived p24 (gag) evaluated by ELISA and Western blot. Jurkat T cells transfected by pCDNA3.3-scFv 183-H12-5C inhibit the replication-competent NL4-3 viral infectivity up to 60%. Conclusion: Anti-p24 scFv 183-H12-5C antibody generated is suitable to be acted as intrabodies and may serve as a valuable tool for the development of antibody-based biotherapeutics against HIV-1

Detection of human parvovirus B19 in papillary thyroid carcinoma

To evaluate whether parvovirus B19, a common human pathogen, was also involved in papillary thyroid carcinoma (PTC), 112 paraffin-embedded thyroid specimens of benign nodules, papillary, medullary and follicular carcinomas, and normal controls were examined for B19 DNA and capsid protein by nested PCR, in situ hybridisation (ISH) and immunohistochemistry (IHC). The expression of the nuclear factor-κB (NF-κB) was investigated by IHC. The results showed B19 DNA commonly exists in human thyroid tissues; however, there were significant differences between PTC group and normal controls, and between PTC and nonneoplastic adjacent tissues (P<0.001). The presence of viral DNA in PTC neoplastic epithelium was confirmed by laser-capture microdissection and sequencing of nested PCR products. B19 capsid protein in PTC group was significantly higher than that of all the control groups and nonneoplastic adjacent tissues (P⩽0.001). Compared with control groups, the activation of NF-κB in PTC group was significantly increased (P⩽0.02), except for medullary carcinomas, and the activation of NF-κB was correlated with the viral protein presence (P=0.002). Moreover, NF-κB was colocalised with B19 DNA in the neoplastic epithelium of PTC by double staining of IHC and ISH. These results indicate for the first time a possible role of B19 in pathogenesis of PTC

Nuclear Factor 90(NF90) targeted to TAR RNA inhibits transcriptional activation of HIV-1

<p>Abstract</p> <p>Background</p> <p>Examination of host cell-based inhibitors of HIV-1 transcription may be important for attenuating viral replication. We describe properties of a cellular double-stranded RNA binding protein with intrinsic affinity for HIV-1 TAR RNA that interferes with Tat/TAR interaction and inhibits viral gene expression.</p> <p>Results</p> <p>Utilizing TAR affinity fractionation, North-Western blotting, and mobility-shift assays, we show that the C-terminal variant of nuclear factor 90 (NF90ctv) with strong affinity for the TAR RNA, competes with Tat/TAR interaction <it>in vitro</it>. Analysis of the effect of NF90ctv-TAR RNA interaction <it>in vivo </it>showed significant inhibition of Tat-transactivation of HIV-1 LTR in cells expressing NF90ctv, as well as changes in histone H3 lysine-4 and lysine-9 methylation of HIV chromatin that are consistent with the epigenetic changes in transcriptionally repressed gene.</p> <p>Conclusion</p> <p>Structural integrity of the TAR element is crucial in HIV-1 gene expression. Our results show that perturbation Tat/TAR RNA interaction by the dsRNA binding protein is sufficient to inhibit transcriptional activation of HIV-1.</p

IL-24 Inhibits lung cancer cell migration and invasion by disrupting the SDF-1/CXCR4 signaling axis

© 2015 Panneerselvam et al. Background The stromal cell derived factor (SDF)-1/chemokine receptor (CXCR)-4 signaling pathway plays a key role in lung cancer metastasis and is molecular target for therapy. In the present study we investigated whether interleukin (IL)-24 can inhibit the SDF-1/CXCR4 axis and suppress lung cancer cell migration and invasion in vitro. Further, the efficacy of IL-24 in combination with CXCR4 antagonists was investigated. Methods Human H1299, A549, H460 and HCC827 lung cancer cell lines were used in the present study. The H1299 lung cancer cell line was stably transfected with doxycycline-inducible plasmid expression vector carrying the human IL-24 cDNA and used in the present study to determine the inhibitory effects of IL-24 on SDF-1/CXCR4 axis. H1299 and A549 cell lines w ere used in transient transfection studies. The inhibitory effects of IL-24 on SDF1/CXCR4 and its downstream targets were analyzed by quantitative RT-PCR, western blot, luciferase reporter assay, flow cytometry and immunocytochemistry. Functional studies included cell migration and invasion assays. Principal Findings Endogenous CXCR4 protein expression levels varied among the four human lung cancer cell lines. Doxycycline-induced IL-24 expression in the H1299-IL24 cell line resulted in reduced CXCR4 mRNA and protein expression. IL-24 post-transcriptionally regulated CXCR4 mRNA expression by decreasing the half-life of CXCR4 mRNA ( > 40%). Functional studies showed IL-24 inhibited tumor cell migration and invasion concomitant with reduction in CXCR4 and its downstream targets (pAKTS 473 , pmTORS 2448 , pPRAS40 T246 and HIF-1α). Additionally, IL-24 inhibited tumor cell migration both in the presence and absence of the CXCR4 agonist, SDF-1. Finally, IL-24 when combined with CXCR4 inhibitors (AMD3100, SJA5) or with CXCR4 siRNA demonstrated enhanced inhibitory activity on tumor cell migration. Conclusions IL-24 disrupts the SDF-1/CXCR4 signaling pathway and inhibits lung tumor cell migration and invasion. Additionally, IL-24, when combined with CXCR4 inhibitors exhibited enhanced anti-metastatic activity and is an attractive therapeutic strategy for lung metastasi

Key signaling nodes in mammary gland development and cancer: β-catenin

β-Catenin plays important roles in mammary development and tumorigenesis through its functions in cell adhesion, signal transduction and regulation of cell-context-specific gene expression. Studies in mice have highlighted the critical role of β-catenin signaling for stem cell biology at multiple stages of mammary development. Deregulated β-catenin signaling disturbs stem and progenitor cell dynamics and induces mammary tumors in mice. Recent data showing deregulated β-catenin signaling in metaplastic and basal-type tumors suggest a similar link to reactivated developmental pathways and human breast cancer. The present review will discuss β-catenin as a central transducer of numerous signaling pathways and its role in mammary development and breast cancer