ABSTRACT
Abstract This study evaluated the effect of a cyclopentenone-type PG, 15-Deoxy-Δ12,14-PG J2 (15d-PGJ2), and lectin (ScLL) on the viability of human gingival fibroblasts (HGFs), and on IL-6 and TGFβ-1 release by these fibroblasts, stimulated with lipopolysaccharide (LPS). HGFs were stimulated with LPS 10 μg/ml and treated with 15d-PGJ2 1 and 2 μg/ml, and ScLL 2 and 5 μg/ml, for 1 and 3h, and then evaluated for viability by MTT assay. Supernatant was collected to detect IL-6 and TGFβ-1 release, by ELISA. Positive control was cells kept in Dulbecco's Modified Eagle's Medium, and negative control was those kept in LPS. Data were analyzed by ANOVA and Dunnett's test (α = 0.05). No significant difference was found in viability among experimental groups at 1h (p > 0.05). Percentage of ScLL 5 µg/ml viable cells was similar to that of positive control at evaluated periods (p > 0.05), whereas the other groups had lower levels than the positive control (p < 0.05). IL-6 release was statistically higher for ScLL 5 μg/ml and 15d-PGJ2 2 µg/ml at 1h, compared with the other treated groups and positive control (p < 0.05). No significant differences were found among the groups at 3h (p > 0.05), except for ScLL 2 µg/ml and 15d-PGJ2 1 µg/ml, which showed lower IL-6 release compared with that of negative control (p < 0.05). No significant difference was found among the groups for TGFβ-1 release (p > 0.05). Results indicated that ScLL 5 μg/ml did not interfere in viability, and ScLL 2 µg/ml and 15d-PGJ2 1 µg/ml demonstrated reduced IL-6 release. Tested substances had no effect on TGFβ-1 release.
Subject(s)
Humans , Prostaglandin D2/analogs & derivatives , Lipopolysaccharides/pharmacology , Interleukin-6/metabolism , Plant Lectins/pharmacology , Transforming Growth Factor beta1/metabolism , Fibroblasts/drug effects , Fibroblasts/metabolism , Reference Values , Time Factors , Enzyme-Linked Immunosorbent Assay , Prostaglandin D2/pharmacology , Cell Survival/drug effects , Cells, Cultured , Analysis of Variance , Statistics, Nonparametric , Transforming Growth Factor beta1/drug effects , Gingiva/cytologyABSTRACT
delta12-Prostaglandin (PG) J2 is known to elicit an anti-neoplastic effects via apoptosis induction. Previous study showed delta12-PGJ2-induced apoptosis utilized caspase cascade through cytochrome c-dependent pathways in HeLa cells. In this study, the cellular mechanism of delta12-PGJ2- induced apoptosis in HeLa cells, specifically, the role of two mitochondrial factors; bcl-2 and apoptosis-inducing factor (AIF) was investigated. Bcl-2 attenuated delta12-PGJ2-induced caspase activation, loss of mitochondrial transmembrane potential (delta psi m), nuclear fragmentation, DNA laddering, and growth curve inhibition for approximately 24 h, but not for longer time. AIF was not released from mitochondria, even if the delta psi m was dissipated. One of the earliest events observed in delta12-PGJ2-induced apoptotic events was dissipation of delta psi m, the process known to be inhibited by bcl-2. Pre-treatment of z-VAD- fmk, the pan-caspase inhibitor, resulted in the attenuation of delta psi m depolarization in delta12-PGJ2- induced apoptosis. Up-regulation of Sox-4 protein by delta12-PGJ2 was observed in HeLa and bcl-2 overexpressing HeLa B4 cell lines. Bcl-2 overexpression did not attenuate the expression of Sox-4 and its expression coincided with other apoptotic events. These results suggest that delta12-PGJ2 induced Sox-4 expression may activate another upstream caspases excluding the caspase 9-caspase 3 cascade of mitochondrial pathway. These and previous findings together suggest that delta12-PGJ2-induced apoptosis in HeLa cells is caspase-dependent, AIF-independent events which may be affected by Sox-4 protein expression up-regulated by delta12-PGJ2.