RESUMO
The Coronavirus disease-2019 (COVID-19) pandemic caused by the Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2), has become a dire global health concern. The development of vaccines with high immunogenicity and safety is crucial for control of the global COVID-19 pandemic and prevention of further illness and fatalities. Here, we report development of SARS-CoV-2 vaccine candidate, Nanocovax, based on recombinant protein production of the extracellular (soluble) portion of the S protein of SARS-CoV-2. The results showed that Nanocovax induced high levels of S protein-specific IgG, as well neutralizing antibody in three animal models including Balb/C mice, Syrian hamsters, and non-human primate (Macaca leonina). In addition, the viral challenge study using the hamster model showed that Nanocovax protected the upper respiratory tract from SARS-CoV-2 infection. No adverse effects were induced by Nanocovax in swiss mice (Musmusculus var. Albino), Rats (Rattus norvegicus), and New Zealand rabbits. These pre-clinical results indicated that Nanocovax is safe and effective.
RESUMO
OBJECTIVE: Hepatocellular carcinoma (HCC), one of the most common cancers worldwide, is resistant to anticancer drugs. Angiogenesis is a major cause of tumor resistance to chemotherapy, and vascular endothelial growth factor (VEGF) is a key regulator of angiogenesis. The purpose of this study is to investigate the impact of small-interfering RNA targeting VEGF gene (VEGF-siRNA) on chemosensitivity of HCC cells in vitro. MATERIALS AND METHODS: In this experimental study, transfection was performed on Hep3B cells. After transfection with siRNAs, VEGF mRNA and protein levels were examined. Cell proliferation, apoptosis and anti-apoptotic gene expression were also analyzed after treatment with VEGF-siRNA in combination with doxorubicin in Hep3B cells. RESULTS: Transfection of VEGF-siRNA into Hep3B cells significantly reduced the expression of VEGF at both mRNA and protein levels. Combination therapy with VEGF-siRNA and doxorubicin more effectively suppressed cell proliferation and induced apoptosis than the respective monotherapies. This could be explained by the significant downregulation of B-cell lymphoma 2 (BCL-2) and SURVIVIN. CONCLUSION: VEGF-siRNA enhanced the chemosensitivity of doxorubicin in Hep3B cells at least in part by suppressing the expression of anti-apoptotic genes. Therefore, the downregulation of VEGF by siRNA combined with doxorubicin treatment has been shown to yield promising results for eradicating HCC cells.
RESUMO
We have constructed two vector systems (pDMS5, pSAB2) containing the promoter regions of the human CYP1A1 gene including xenobiotic response elements or the promoter region of the Xenopus laevis vitellogenin A2 gene including estrogen response elements, respectively, and the genes for green fluorescent protein and firefly luciferase. These vectors were transfected into CHO-K1 cells. Transiently transfected cells consistently responded to 1 nmol/l TCDD (dioxin) or 10 nmol/l 17ss-estradiol, respectively, with a 3-5 fold increase in luciferase activity. Permanent cell lines were selected by culturing transiently transfected cells under continued presence of antibiotics and dilution cloning. Cells which had stably integrated the vector-DNA into the genomic DNA were selected. SiF6 cells responded to treatment with TCDD, PCB126, benzo(a)pyrene or indirubin-3'-monoxime in the concentration range between 0 and 1 micromol/l. SiG12 cells responded to treatment with bisphenol A, 4-MBC and DDT in the concentration range between 0 and 10 micromol/l. Compared with the controls, luciferase mRNA-abundance (semi-quantitative RT-PCR) and luciferase activity (luminescence assay) were elevated up to 3-fold. Resveratrol or tamoxifen, respectively, worked as full antagonists. Luciferase expression was increased upon treatment of cells with extracts of spiked soil samples indicating that our systems are suited for screening of environmental samples.
