?1,4-Galactosyltransferase V Modulates Breast Cancer Stem Cells through Wnt/?-catenin Signaling Pathway.

ABSTRACT: PURPOSE:Breast cancer stem cells (BCSCs) contribute to the initiation, development, and recurrence of breast carcinomas. ?1,4-Galactosyltransferase V (B4GalT5), which catalyzes the addition of galactose to GlcNAc?1-4Man of N-glycans, is involved in embryogenesis. However, its role in the modulation of BCSCs remains unknown. Materials and Methods:The relationship between B4GalT5 and breast cancer stemness was investigated by online clinical databases and immunohistochemistry analysis. Mammosphere formation, fluorescence-activated cell sorting (FACS), and in-vivo assays were used to evaluate B4GalT5 expression in BCSCs and its effect on BCSCs. B4GalT5 regulation of Wnt/?-catenin signaling was examined by immunofluorescence and Ricinus communis agglutinin I pull-down assays. Cell surface biotinylation and FACS assays were performed to assess the association of cell surface B4GalT5 and BCSCs. RESULTS:B4GalT5, but not other B4GalTs, was highly correlated with BCSC markers and poor prognosis. B4GalT5 significantly increased the stem cell marker aldehyde dehydrogenase 1A1 (ALDH1A1) and promoted the production of CD44+CD24-/low cells and the formation of mammospheres. Furthermore, B4GalT5 overexpression resulted in dramatic tumor growth in vivo. Mechanistically, B4GalT5 modified and protected Frizzled-1 from degradation via the lysosomal pathway, promoting Wnt/?-catenin signaling which was hyperactivated in BCSCs. B4GalT5, located on the surface of a small subset of breast carcinoma cells, was not responsible for the stemness of BCSCs. CONCLUSION:B4GalT5 modulates the stemness of breast cancer through glycosylation modification to stabilize Frizzled-1 and activate Wnt/?-catenin signaling independent of its cell surface location. Our studies highlight a previously unknown role of B4GalT5 in regulating the stemness of breast cancer and provide a potential drug target for anticancer drug development.

SUBMITTER: Tang W 

PROVIDER: S-EPMC7577798 | biostudies-literature | 2020 Oct

REPOSITORIES: biostudies-literature