Cucurbitacin IIA (CuIIa), a member of cucurbitacin family, is isolated from the root of Hemsleya amabilis which has been used as an ancient remedy for bacillary dysentery and gastroenteritis. The anti-inflammatory properties of Cucurbitacin IIA have long been recognized but the underlying mechanism is largely unknown. METHODS AND RESULTS: In this study, we investigated the anti-inflammatory effect of Cucurbitacin IIA on lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophage cells. The results showed that Cucurbitacin IIA inhibited the proliferation and migration of RAW 264.7 cells in a dose-dependent manner. Whereas Cucurbitacin IIA did not cause apoptosis in unstimulated RAW 264.7 cells, it did induce a significant apoptosis in LPS-stimulated cells, which was caspase-3-dependent and associated with downregulation of survivin. Furthermore, LPS induced autophagy in RAW 264.7 cells and this effect was further enhanced by Cucurbitacin IIA as evidenced by increased levels of LC3-II conjugates and formation of LC3 puncta. In addition, Cucurbitacin IIA disrupted actin cytoskeleton via inducing actin aggregation. However, neither the synthesis of tumor necrosis factor-α, nor the activation of the mitogen-activated protein kinases and NF-κB pathways in LPS-stimulated cells was suppressed by Cucurbitacin IIA treatment. CONCLUSIONS: Collectively, these results suggested that induction of apoptosis and enhancement of autophagy contributed to the anti-inflammatory activity of Cucurbitacin IIA against inflammation-related diseases. |