OBJECTIVETo investigate the dual role of daphnetin in suppressing high mobility group box-1 protein (HMGB1) release and blocking HMGB1-induced inflammatory response.

METHODSMurine macrophage RAW264.7 cells were cultured in the presence of daphnetin, lipopolysaccharide (LPS), or both. HMGB1 release from the cells was determined using ELISA, and phosphorylations of JAK1/2 and of STAT1 were detected by Western blotting. Human monocytic THP-1 cells exposed to daphnetin, rhHMGB1, or both were examined for NO production using a NO detection kit, for the release of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and prostaglandin E2 (PGE2) using ELISA, and for expressions of iNOS, COX-2 and phosphorylated p38, ERK, and JNK with Western blotting.

RESULTSDaphnetin dose-dependently reduced the release of HMGB1 in RAW264.7 cells and suppressed rhHMGB1-induced iNOS and COX-2 expressions and release of TNF-α, IL-6, PGE2, and NO in THP-1 cells. Western blotting revealed that daphnetin significantly down-regulated the phosphorylations of JAK-STAT1 pathway in LPS-stimulated RAW264.7 cells but did not suppress the phosphorylations of MAPKs signaling pathway induced by rhHMGB1 in THP-1 cells.

CONCLUSIONDaphnetin can reduce the release of HMGB1 and suppress HMGB1-induced inflammatory response. In RAW264.7 cells, daphnetin inhibited LPS induced HMGB1 release is at least partly mediated by suppressing JAK-STAT1 signaling pathway activation.

Animals ; Cell Line ; Cyclooxygenase 2 ; metabolism ; Dinoprostone ; metabolism ; HMGB1 Protein ; metabolism ; Humans ; Inflammation ; metabolism ; Interleukin-6 ; metabolism ; Janus Kinase 1 ; metabolism ; Lipopolysaccharides ; Macrophages ; drug effects ; Mice ; Monocytes ; drug effects ; Nitric Oxide ; metabolism ; Nitric Oxide Synthase Type II ; metabolism ; RAW 264.7 Cells ; STAT1 Transcription Factor ; metabolism ; Signal Transduction ; drug effects ; Tumor Necrosis Factor-alpha ; metabolism ; Umbelliferones ; pharmacology

[Abstract] Objective:To explore the targeting relationship between long-chain noncoding RNA HOXA-AS2 (lncRNA HOXA-AS2) and microRNA-520a-3p (miR-520a-3p) and their effects on the proliferation, migration and invasion of ovarian cancer SKOV3 cells. Methods： ：qPCR was used to detect the expression levels of lncRNA HOXA-AS2 and miR-520a-3p in various ovarian cancer cell lines (SKOV3, HO8910, OVCAR3 cells) and normal ovarian epithelial cell line HOSE. Bioinformatics methods were used to predict the targeting relationship between HOXA-AS2 and miR-520a-3p, which was then verified by Dual luciferase reporter gene assay. si-HOXA-AS2, miR-520a-3p mimic, anti-miR-520a-3p and corresponding control fragments were transfected into SKOV3 cells separately or in combination. MTT, Transwell and Western blotting were used to detect the proliferation, migration, invasion and expressions of related proteins (CyclinD1, p21, p27, MMP-2, MMP-9, MMP-14) of SKOV3 cells in each group. Results: Compared with HOSE cells, HOXA-AS2 was over-expressed while miR-520a-3p was under-expressed in ovarian cancer cell lines (all P<0.05). HOXA-AS2 could targetedly down-regulate the expression of miR-520a-3p. Compared with the NC group, the proliferation, migration and invasion of SKOV3 cells in the si-HOXA-AS2 and miR-520a-3p mimics groups were significantly reduced (all P<0.01), and the protein expressions of p21 and p27 were significantly increased, while protein expressions of CyclinD1, MMP-2, MMP-9, MMP-14 were significantly reduced (all P<0.01). The proliferation, migration and invasion of SKOV3 cells in the si-HOXA-AS2+antimiR-520a-3p group were significantly enhanced compared with those in si-HOXA-AS2 and si-HOXA-AS2+anti-miR-NC groups (all P<0.05). Conclusion: lncRNA HOXA-AS2 enhances the proliferation, migration and invasion of ovarian cancer SKOV3 cells by targetedly inhibiting the expression of miR-520a-3p.