Calpain/SHP-1 Interaction by Honokiol Dampening Peritoneal Dissemination of Gastric Cancer in nu/nu Mice

Background: Honokiol, a small-molecular weight natural product, has previously been reported to activate apoptosis and inhibit gastric tumorigenesis. Whether honokiol inhibits the angiogenesis and metastasis of gastric cancer cells remains unknown. Methodology/Principal Findings: We tested the effects of honokiol on angiogenic activity and peritoneal dissemination using in vivo, ex vivo and in vitro assay systems. The signaling responses in human gastric cancer cells, human umbilical vascular endothelial cells (HUVECs), and isolated tumors were detected and analyzed. In a xenograft gastric tumor mouse model, honokiol significantly inhibited the peritoneal dissemination detected by PET/CT technique. Honokiol also effectively attenuated the angiogenesis detected by chick chorioallantoic membrane assay, mouse matrigel plug assay, rat aortic ring endothelial cell sprouting assay, and endothelial cell tube formation assay. Furthermore, honokiol effectively enhanced signal transducer and activator of transcription (STAT-3) dephosphorylation and inhibited STAT-3 DNA binding activity in human gastric cancer cells and HUVECs, which was correlated with the up-regulation of the activity and protein expressio