ABSTRACT
OBJECTIVE: Epidemiological studies suggest that selenium protects against the development of several cancers. Selenium (sodium selenite) has been reported to interfere with cell growth and proliferation, and to induce cell death. In this study, we tested whether selenium could have growth-inhibiting effect in ovarian cancer cells and an orthotopic animal model. METHODS: Cell growth in selenium-treated cells was determined in human ovarian cancer cells, A2780, HeyA8, and SKOV3ip1 using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide (MTT) assay. Animal experiment of selenium with paclitaxel was performed using SKOV3ip1 cells in nude mice to evaluate their inhibiting effect for tumor growth. In addition, another animal experiment of paclitaxel with or without selenium was performed to assess the effect of survival and food intake in mice. RESULTS: The in vitro growth of selenium-treated cells was significantly decreased dose-dependently in A2780, HeyA8, and SKOV3ip1 cells. Therapy experiment in mice was started 1 week after injection of the SKOV3ip1 cells. Treatment with selenium (1.5 mg/kg, 3 times/week) and paclitaxel injection showed no addictive effect of the inhibition of tumor growth. However, combination of selenium and paclitaxel showed the slightly increased food intake compared with paclitaxel alone. CONCLUSION: Although selenium has growth-inhibiting effect in ovarian carcinoma cells in vitro, there is no additive effect on tumor growth in mice treated with combination of paclitaxel and selenium. However, food intake is slightly higher in selenium-treated mice during chemotherapy.
Subject(s)
Animals , Humans , Mice , Animal Experimentation , Cell Death , Cell Survival , Eating , Mice, Nude , Ovarian Neoplasms , Paclitaxel , Selenium , Sodium SeleniteABSTRACT
Considerable effort has been directed at understanding the structure and function of HIV-1 envelope glycoproteins. It has been difficult to characterize HIV-1 envelope glycoproteins due to the limited availability of these proteins from virus particles or infected cells. To facilitate the structural and functional analysis of HIV-1 envelope glycoproteins, recombinant baculoviruses were generated to express wild type or mutant HIV-1 envelope glycoproteins. The gp160 precursor protein as well as the gp120 glycoprotein were detected in the cell infected with recombinant BacENVw.t containing wild type HIV-1 envelope gene. In the insect cells infected with recombinant BacENVc with mutations at the cleavage site of gp160, a precursor form of envelope glycoprotein was produced, but not secreted into the culture medium. However, the insect cells infected with recombinant BacENVc/t containing both mutations at the cleavage site and membrane spanning region produced mutant envelope glycoproteins that were efficiently secreted into the culture medium in the form of precursor. Therefore the recombinant HIV-1 envelope glycoproteins produced in this system would be useful as immunogens in the development of a vaccine against AIDS.
Subject(s)
Humans , Baculoviridae , Glycoproteins , HIV , HIV-1 , Insecta , Membranes , Staphylococcal Protein A , VirionABSTRACT
Human immunodeficiency virus type 1(HIV-1) envelope glycoprotein is synthesized as a 160KDa precursor, gp160, that is cleaved by a cellular protease to form the gp120 and gp41 subunits. Mammalian expression vectors were designed that are capabae of efficient expression of various mutant envelope glycoproteins derived from a molecular clone of HIV-1. To construct these vectors, one type of mutation was made at the gp120-gp41 cleavage site by oligonucleotide directed mutagenesis. And another mutation was made to change amino acids in the membrane spanning region of HIV-1 gp41 important for membrane anchorage. Next, these two mutations were combined to generate a vector to have double mutations in cleavage site and membrane spanning region. These mutants were transiently expressed in mammalian cells. The effect of these mutations on envelope glycoprotein synthesis, proteolytic processing and secretion was determined. In addition, cell surface expression and ability of the glycoprotein to induce syncytium formation were examined. This study provides a mammalian expression system that is capable of efficient expression and secretion of soluble gp160.