Tanshinone IIA induces apoptosis in fibroblast-like synoviocytes in rheumatoid arthritis via blockade of the cell cycle in the G2/M phase and a mitochondrial pathway

Abstract

Tanshinone IIA (Tan IIA), a phytochemical derived from the roots of Salvia miltiorrhiza BUNGE, has been documented with anti-tumor, pro-apoptotic, and anti-inflammatory activities. Salvia miltiorrhiza has long been used to treat rheumatoid arthritis (RA). Apoptosis induction of RA-FLS was suggested to be a potential therapeutic approach for RA. The aim of this study was to investigate whether Tan IIA promotes apoptosis in RA-affected fibroblast-like synoviocytes (FLS). In this study, the viability of an immortalized FLS cell line derived from RA patients was assessed by MTS assay after Tan IIA treatment. Apoptosis was measured by terminal dUTP nick-end labeling (TUNEL) assay and flow cytometry. Cell cycle was evaluated by flow cytometry. The expressions of mitochondrial apoptosis-related molecules, including Bcl-2, Bax, mitochondrial cytochrome c(Cyt-c), cytosolic Cyt-c, apoptotic protease activating factor 1 (Apaf-1), procaspase-9, procaspase-3, caspase-9, and caspase-3 were determined by Western blotting. Our data demonstrate that Tan IIA induced apoptosis of RA-FLS, blocked the cell cycle in the G2/M phase, and regulated the protein expression of Bcl-2, Bax, and Apaf-1, the release of mitochondrial Cyt-c, and the activation of caspase-9 and caspase-3. The results support the conclusion Tan IIA treatment likely induces apoptosis of RA-FLS through blockade of the cell cycle in the G2/M phase and a mitochondrial pathway. These data suggest that Tan IIA may have therapeutic potential for RA.