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Interaction of Disialyl Gangliosides GD2/GD3 with Growth Factor Receptors Sustains the Stem Cell Phenotype of Breast Cancer
Author(s) -
LIANG YUHJIN
Publication year - 2015
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.29.1_supplement.890.11
Subject(s) - colocalization , microbiology and biotechnology , gene knockdown , chemistry , epidermal growth factor receptor , stem cell , receptor , immunoprecipitation , epidermal growth factor , growth factor , signal transduction , cancer research , biology , biochemistry , apoptosis , gene
Our previous studies demonstrated a causal relationship between GD2/GD3 gangliosides and maintenance of breast cancer stem cells (BCSCs) properties, based on reversal of stem cells properties following knockdown of GD2/GD3 synthases. Recently, we analyzed growth factor receptors (GFRs) associated with GD2/GD3 and their related signaling pathways to clarify how interactions with GD2/GD3 maintain stem cell properties and signaling in BCSCs. Immunofluorescence staining indicated that most GD3 is co‐localized with epidermal growth factor receptor (EGFR). In contrast, GD2 and cMet showed only partial colocalization in the ER‐Golgi intermediate compartment. Interactions between GD2/GD3 and GFRs were also detected by co‐immunoprecipitation of BCSC lysates with anti‐GD2 and anti‐GD3 antibodies. We observed that there was strong interaction between GD3 and EGFR but weak GD2/ cMet association. On the other hand, β1‐integrin, which modulates functions of various GFRs, was strongly associated with GD2. Immunogold labeling and transmission electron microscopy confirmed the localization of GD2/GD3 and GFRs in membrane microdomains. GD3 was clustered with EGFR in electron‐dense membrane patches, whereas GD2 and cMet showed little colocalization on BCSC membrane sheets. EGFR expression and ERK signaling were increased in BCSC populations showing high GD2/GD3 expression. Co‐immunoprecipitation with a chemical cross‐linker in living cells was used to identify protein complexes associated with GD2/GD3. A nano‐LC‐MS/MS showed there was a total of 143 GD2‐associated and 320 GD3‐associated proteins. Our findings provide an important basis for further studies of functional molecular interactions that maintain stem cell properties in BCSCs.