Salvianolic acid B acts against non‑small cell lung cancer A549 cells via inactivation of the MAPK and Smad2/3 signaling pathways

Salvianolic acid B (Sal B) is a potential cytotoxic polyphenol against cancer. In the present study the effect of Sal B and its molecular mechanism were investigated in the non‑small cell lung cancer (NSCLC) A549 cell line. The TGF‑β/MAPK/Smad signaling axis was explored. A549 cells were co‑cultured with and without different concentrations of Sal B (25, 50 and 100 µM respectively) and TGF‑β1 (9 pM) for 24 h. Cell epithelial‑mesenchymal transition (EMT), cell migration, cell cycle distribution, autophagy and apoptosis were assessed by western blotting (WB), wound healing assay and flow cytometry, respectively. Moreover, activation of MAPK, Smad2/3 and the downstream target, plasminogen activator inhibitor 1 (PAI‑1), were assessed by WB. The results demonstrated that Sal B inhibited TGF‑β1‑induced EMT and migration of A549 cells, hampered cell cycle progression and induced cell autophagy and apoptosis. Furthermore, Sal B inactivated MAPK signaling pathways and the phosphorylation of Smad2/3, especially the phosphorylation of Smad3 at the linker region, which resulted in decreased protein expression levels of PAI‑1 in TGF‑β1‑stimulated A549 cells. Overall, these results demonstrated that Sal B may have a potential therapeutic effect against NSCLC in vitro. The results of the present study indicated that the underlying active mechanism of Sal B in NSCLC may be closely related to the impeded activation of the MAPK and Smad2/3 signaling pathways. Therefore, Sal B may be a potential candidate NSCLC therapeutic agent.

Salvianolic acid B inhibits myofibroblast differentiation and extracellular matrix accumulation in nasal polyp fibroblasts via the TGF-β1 signaling pathway

In the process of nasal tissue remodeling, nasal fibroblasts serve an important role via myofibroblast differentiation and the production of extracellular matrix (ECM). Nasal fibroblast abnormalities can lead to conditions such as chronic rhinosinusitis. Salvianolic acid B (Sal B), a water-soluble active pharmaceutical compound extract from the root of the traditional Chinese medicine Salvia miltiorrhiza, displays antioxidative, antiproliferative and antifibrosis properties. The present study aimed to investigate the mechanism underlying the effects of Sal B on nasal polyp fibroblast (NPF) myofibroblast differentiation and ECM accumulation. Primary NPFs were obtained from nasal polyps of patients with chronic sinusitis. The proliferative and cytotoxic effects of Sal B on NPFs were evaluated by performing the Cell Counting Kit-8 assay. The Transwell assay was conducted to assess cell migration. α-smooth muscle actin (α-SMA), TGF-β1 receptor (TβR)-I, TβR-II, Smad2/3 mRNA and protein expression levels and (p)-Smad2/3 phosphorylation levels were measured via reverse transcription-quantitative PCR and western blotting, respectively. Type III collagen and fibronectin levels were analyzed by ELISA. The results indicated that Sal B significantly downregulated TGF-β1-induced α-SMA, fibronectin and collagen III expression levels in NPFs. Similarly, Sal B significantly decreased TGF-β1-induced TβR-I, TβR-II, p-Smad2/3, MMP-2 and MMP-9 mRNA and protein expression levels in NPFs. Furthermore, Sal B significantly decreased TGF-β1-induced NPF migration. Therefore, the present study indicated that Sal B inhibited myofibroblast differentiation and ECM accumulation in nasal fibroblasts, suggesting that Sal B may inhibit nasal polyp formation via certain mechanisms.