Hybridoma monoclonal antibody 15B7 targeting ESA-positive liver cancer stem cells inhibits cell invasion and cisplatin resistance in vitro

Objective: To study the in vitro function of a monoclonal antibody (McAb) 15B7 which is secreted by hybridoma cells and can recognize the epithelial specific antigen (ESA)-positive liver cancer stem cells, and to provide candidate antibody drug for cancer stem cells-targeted therapy of liver cancer.Methods: Cell culture in serum-free medium and PKH26 staining were used to determine the existence of cancer stem cells in human liver cancer Bel7402-V3 cell line. Flow cytometry and double color immunofluorescence were used to detect the coexpressions of ESA and recognized antigen of McAb 15B7. The effects of McAb 15B7 on self-renewal, cisplatin-resistance and invasive abilities of  Bel7402-V3 cells were examined by serum-free suspension culture, cell counting kit-8 (CCK-8) assay and Transwell assay, respectively.Results: The single PKH26 staining-positive cells were observed in spheroids after Bel7402-V3 cells had been cultured in serum-free medium for 11 days. The co-localization of McAb 15B7 recognized antigen and ESA was observed in Bel7402-V3 cells. McAb 15B7 significantly inhibited the sphere formation of Bel7402-V3 cells in serum-free medium (P < 0.05), with the inhibitory rate being 32.4%. McAb 15B7 also significantly suppressed the cisplatin-resistance of Bel7302-V3 cells (P < 0.05). The half maximal inhibitory concentrations were 0.14 μg/mL and 0.27 μg/mL in 15B7 treated group and 15B7 untreated control group, respectively. Meanwhile, McAb 15B7 could inhibit the invasive ability of Bel7402-V3 cells (P < 0.05), and the inhibitory rate was 30.7%.Conclusion: McAb 15B7 can inhibit self-renewal, invasive ability and drug-resistance of ESA-positive liver cancer stem cells, and it might become a worthy potential antibody-drug for liver cancer stem cells-targeted treatment. DOI:10.3781/j.issn.1000-7431.2015.11.048