Abstract: OBJECTIVE To investigate the effect and mechanism of sinomenine on apoptosis of pancreatic cancer Capan-1 cells. METHODS CCK8 assay was used to detect cell viability. DAPI/TUNEL staining was used to detect cell apoptosis. Flow cytometry Annexin V-FITC/PI was used to detect cell apoptotic rate. Western blotting was used to detect the expression of cleaved caspase-3 and nuclear NF-kB protein. RESULTS Result of CCK8 assay showed that sinomenine can inhibit the proliferation of Capan-1 cells effectively in a dose and time dependent manner. Result of DAPI/TUNEL staining showed that the apoptosis of Capan-1 cells increased by treated with sinomenine. Flow cytometric analysis staining with Annexin V-FITC/PI showed that the apoptosis rates of Capan-1 cells increased by treated with sinomenine. Result of Western blotting analysis showed that the expression of cleaved caspase-3 increaed and the expression of nuclear NF-kB decreased in Capan-1 cells by treated with sinomenine. TNF-a could reversed the effect of sinomenine on the proliferation and apoptosis of Capan-1 cell. TNF-a could reversed the up-regulated effect of sinomenine on the expression of cleaved caspase-3 in Capan-1 cells. CONCLUSION Sinomenine inhibits proliferation and induces apoptosis of pancreatic cancer Capan-1 cells by regulating the NF-kB signaling pathway.