ABSTRACT
Abstract Glioblastoma is the most common malignant brain tumor representing with poor prognosis, therapy resistance and high metastasis rate. Increased expression and activity of matrix metalloproteinase-2, a member of matrix metalloproteinase family proteins, has been reported in many cancers including glioblastoma. Inhibition of matrix metalloproteinase-2 expression has resulted in reduced aggression of glioblastoma tumors in several reports. In the present study, we evaluated effect of bee venom on expression and activity of matrix metalloproteinase-2 as well as potential toxicity and apoptogenic properties of bee venom on glioblastoma cells. Human A172 glioblastoma cells were treated with increasing concentrations of bee venom. Then, cell viability, apoptosis, matrix metalloproteinase-2 expression, and matrix metalloproteinase-2 activity were measured using MMT assay, propidium iodide staining, real time-PCR, and zymography, respectively. The IC50 value of bee venom was 28.5 µg/ml in which it leads to decrease of cell viability and induction of apoptosis. Incubation with bee venom also decreased the expression of matrix metalloproteinase-2 in this cell line (p < 0.05). In zymography, there was a reverse correlation between bee venom concentration and total matrix metalloproteinase-2 activity. Induction of apoptosis as well as inhibition of matrix metalloproteinase-2 activity and expression can be suggested as molecular mechanisms involved in cytotoxic and antimetastatic effects of bee venom against glioblastoma cells.
ABSTRACT
Antioxidant properties of ghrelin have been recently reported in animal models and cell culture experiments. This study was set to examine the possible in vitro and in vivo anti-oxidative effects of ghrelin in rat and HepG2 cell culture. In this study, thirty six male Wistar Rats were randomly allocated into six experimental groups of six; Intraperitoneally, group 1 (Control) received 1 ml PBS, group 2 received 0.1 mM/kg tert-Butylhydroperoxide (t- BOOH), groups 3 and 4 received 0.1 mM/kg t-BOOH and then received 10 and 50 μg/kg ghrelin, respectively. Groups 5 and 6 received 10 and 50 μg/kg ghrelin, respectively. Rats were anesthetized 24 h after last injection and blood samples were taken by cardiac puncture. Carbonylated proteins, nitric oxide (NO) and total antioxidant capacity (TAC) levels were measured in sera. HepG2 cells were plateaued at a density of 1.5 x 105 per well in eight plates. After treatment with ghrelin (0, 10, 25 and 50 nM) for 30 min, cells were treated with TBOOH (100 or 200 μM) for 24 h to analyze cell proliferation by MTT assay at 570 nm. Evidence of oxidative stress including increased carbonylated proteins and NO levels and decreased TAC level were observed after t- BOOH injection. In rats with oxidative stress, subsequent treatment with ghrelin decreased NO and carbonylated proteins level and increased TAC level. The cell viability was decreased after t-BOOH treatment in dose dependent manner; in contrast, ghrelin in all used concentrations caused an elevation in cell viability after 24 h incubation time. These data taken together indicate that ghrelin reduces oxidative stress, but its exact mechanism is yet to be investigated.