AIM: Increasing evidence suggests that carbohydrate-binding proteins play an essential role in tumor growth and metastasis. Galectin-3,a multifunctional protein of an expanding family of β-galactoside-binding animal lectins,is the major nonintegrin cellular laminin-binding protein,and is implicated in a variety of biologic events,such as inflammation and angiogenesis. Because galectin-3expression was shown to participate in mediating tumor angiogenesis and initiate signaling cascades in several diseases. We hypothesized that galectin-3 may promote pulmonary vascular endothelial neovascularization. METHODS: Hypoxic and MCT rat model of pulmonary artery remodeling was used. The m RNA and protein levels of galectin-3 in rats were measured by in situ hybrization and Western blot analysis. Endothelial cell( EC) proliferation,migration and tube formation were measured using MTT,cell scratch and Matrigel assays,respectively. Protein expression was quantitated by Western blot analysis. LC 3A / B staining was detected with cellular immunofluorescence staining. RESULTS: We found that galectin-3 was localized on the intima and adventitial wall. Galectin-3 was increased after rat hypoxia and MCT administration. Galectin-3 promoted EC proliferation,migration and tube formation,while its roles were reversed by RNA interference. Galectin-3 induced Atg 5,Beclin-1,LAMP-2,and LC 3A / B expression increases. Galectin-3 also increased LC 3A / B staining in ECs. Akt / m TOR and GSK-3β signaling pathways were activated after galectin-3 treated ECs using its specific phosphorylation antibodies,while blocked it with LY294002 inhibited cell autophagy and EC dynamic alterations induced by galectin-3. CONCLUSION: These findings demonstrate that galectin-3 can induce an Akt signaling cascade leading to cell autophagy,and then the differentiation and angiogenesis of pulmonary artery endothelial cells. AIM: Increasing evidence suggests that carbohydrate-binding proteins play an essential role in tumor growth and metastasis. Galectin-3, a multifunctional protein of an expanding family of β-galactoside-binding animal lectins, is the major nonintegrin cellular laminin-binding protein, and is implicated in a variety of biologic events, such as inflammation and angiogenesis. METHODS We show that both galectin-3 expression was shown to participate in mediating tumor angiogenesis and other signaling pathways in several diseases. We hypothesized that galectin-3 may promote pulmonary vascular endothelial neovascularization. METHODS : Hypoxic and MCT rat model of pulmonary artery remodeling was used. The m RNA and protein levels of galectin-3 in rats were measured by in situ hybrization and Western blot analysis. Endothelial cell (EC) proliferation, migration and tube formation were measured using MTT, cell scratch and Matrigel assays, respectively. Protein expression was quantitated by Western blot analysis. LC 3A RESULTS: We found that galectin-3 was localized on the intima and adventitial wall. Galectin-3 was increased after rat hypoxia and MCT administration. Galectin-3 promoted EC proliferation, migration and tube formation , while while their positions were reversed by RNA interference. Galectin-3 induced Atg 5, Beclin-1, LAMP-2, and LC 3A / B expression increases. Galectin-3 also increased LC 3A / B staining in ECs. Akt / m TOR and GSK-3β signaling pathways were activated after galectin-3 treated ECs using its specific phosphorylation antibodies, while blocked it with LY294002 inhibited cell autophagy and EC dynamic alterations induced by galectin-3. CONCLUSION: These findings demonstrate that galectin-3 can induce an Akt signaling cascade leading to cell autophagy, and then the differentiation and angiogenesis of pulmonary artery endothelial cells.