Enhancive effects of Lewis y antigen on CD44-mediated adhesion and spreading of human ovarian cancer cell line RMG-I

<jats:title>Abstract</jats:title> <jats:sec> <jats:title>Background</jats:title> <jats:p>This study aimed to investigate the molecular structural relationship between cell adhesive molecule CD44 and Lewis y antigen, and determine the effects of Lewis y antigen on CD44-mediated adhesion and spreading of ovarian cancer cell line RMG-I and the Lewis y antigen-overexpressed cell line RMG-I-H.</jats:p> </jats:sec> <jats:sec> <jats:title>Methods</jats:title> <jats:p>The expression of CD44 in RMG-I and RMG-I-H cells before and after treatment of Lewis y monoclonal antibody was detected by immunocytochemistry; the expression of Lewis y antigen and CD44 was detected by Western Blot. The structural relationship between Lewis y antigen and CD44 was determined by immunoprecipitation and confocal laser scanning microscopy. The adhesion and spreading of RMG-I and RMG-I-H cells on hyaluronic acid (HA) were observed. The expression of CD44 mRNA in RMG-I and RMG-I-H cells was detected by real-time RT-PCR.</jats:p> </jats:sec> <jats:sec> <jats:title>Results</jats:title> <jats:p>Immunocytochemistry revealed that the expression of CD44 was significantly higher in RMG-I-H cells than in RMG-I cells (<jats:italic>P</jats:italic> < 0.01), and its expression in both cell lines was significantly decreased after treatment of Lewis y monoclonal antibody (both <jats:italic>P</jats:italic> < 0.01). Western Blot confirmed that the content of CD44 in RMG-I-H cells was 1.46 times of that in RMG-I cells. The co-location of Lewis y antigen and CD44 was confirmed by co-immunoprecipitation. The co-expression of CD44 and Lewis y antigen in RMG-I-H cells was 2.24 times of that in RMG-I cells. The adhesion and spreading of RMG-I-H cells on HA were significantly enhanced as compared to those of RMG-I cells (<jats:italic>P</jats:italic> < 0.01), and this enhancement was inhibited by Lewis y monoclonal antibody (<jats:italic>P</jats:italic> < 0.01). The mRNA level of CD44 in both cell lines was similar (<jats:italic>P</jats:italic> > 0.05).</jats:p> </jats:sec> <jats:sec> <jats:title>Conclusion</jats:title> <jats:p>Lewis y antigen strengthens CD44-mediated adhesion and spreading of ovarian cancer cells.</jats:p> </jats:sec>