3958

LGALS3

BACKGROUND: Galectin-3 (Gal3) plays diverse roles in cancer initiation, progression, and drug resistance depending on tumor type characteristics that are also associated with cancer stem cells (CSCs). Recurrence of breast carcinomas may be attributed to the presence of breast CSCs (BCSCs). BCSCs exist in mesenchymal-like or epithelial-like states and the transition between these states endows BCSCs with the capacity for tumor progression. The discovery of a feedback loop with galectins during epithelial-to-mesenchymal transition (EMT) prompted us to investigate its role in breast cancer stemness. METHOD: To elucidate the role of Gal3 in BCSCs, we performed various in vitro and in vivo studies such as sphere-formation assays, Western blotting, flow cytometric apoptosis assays, and limited dilution xenotransplant models. Histological staining for Gal3 in tissue microarrays of breast cancer patients was performed to analyze the relationship of clinical outcome and Gal3 expression. RESULTS: Here, we show in a cohort of 87 node-positive breast cancer patients treated with doxorubicin-based chemotherapy that low Gal3 was associated with increased lymphovascular invasion and reduced overall survival. Analysis of in vitro BCSC models demonstrated that Gal3 knockdown by small hairpin RNA (shRNA) interference in epithelial-like mammary spheres leads to EMT, increased sphere-formation ability, drug-resistance, and heightened aldefluor activity. Furthermore, Gal3(negative) BCSCs were associated with enhanced tumorigenicity in orthotopic mouse models. CONCLUSIONS: Thus, in at least some breast cancers, loss of Gal3 might be associated with EMT and cancer stemness-associated traits, predicts poor response to chemotherapy, and poor prognosis.

Objective To explore the role of Galectin3 in transforming growth factor-beta(TGF-beta)-induced epithelial-mesenchymal transition (EMT) in A549 cells. Methods Galectin3 was over-expressed in an A549 cell line. EMT was induced in lung cancer A549 cells by adding TGF-beta. The expressions of Galectin3,E-cadherin,and vimentin were determined by Western blot. The protein expression of E-cadherin and the morphological changes of the cells were detected by immunofluorescence. Cellular proliferation was analyzed with cell counting kit-8,and the cellular migration and invasion was measured by scratches healing and Transwell assay,respectively.Results When only Galectin3 was over-expressed in A549 cell line,the expression levels of EMT-related proteins such as E-cadherin and vimentin were not changed,and the abilities of cellular proliferation,invasion,and migration were not changed either. When the EMT was induced by TGF-beta in A549 cells,the E-cadherin expression was down-regulated and the vimentin expression was up-regulated in A549 cells with Galectin3 over-expression. There was no significant change in cellular proliferation,whereas the abilities of cellular invasion and migration were enhanced.Conclusion The TGF-beta-induced EMT in A549 cells can be enhanced by Galectin3.