Downregulation of CD24 inhibits invasive growth, facilitates apoptosis and enhances chemosensitivity in gastric cancer AGS cells.

BACKGROUND AND AIM The human CD24 antigen is a small heavily glycosylated cell surface protein, which is expressed in a large variety of solid tumors,including gastric cancer. Enriched on the surface of many tumor cells,CD24 promotes tumor growth,invasion and metastasis and confers resistance to some chemotherapeutic drugs.In this study, we investigated the possible effect of CD24 suppression on proliferation, apoptosis, migration, invasion and chemosensitivity of gastric cancer (GC) cells. MATERIALS AND METHODS We down-regulated CD24 expression by RNA interference and investigated the effects on proliferation, apoptosis, chemosensitivity to doxorubicin, malignant and metastatic potential of a human gastric cancer cell line, AGS, CD24-suppressed clones, AGS-CD24-siRNA-C2, AGS-CD24-siRNA-C4 and AGS-CD24-siRNA-C5 in vitro. We evaluated the effects of CD24 suppression in vivo on xenograft tumor growth and metastatic properties following tail iv AGS-CD24-siRNA-C2, AGS-CD24-siRNA-C4 and AGS-CD24-siRNA-C5 clones. We also investigated the effect of CD24-siRNA followed by doxorubicin administration treatment on the xenograft tumor growth. RESULTS CD24 suppressed showed significantly decreased proliferation, invasion and increased apoptosis as well as increased chemosensitivity to doxorubicin in vitro and in vivo. CONCLUSIONS CD24 involves in proliferation, invasion and chemosensitivity of human gastric cancer cell line AGS, and that down-regulation of CD24 protein expression decreases the metastatic potential and increases chemosensitivity of gastric cancer (GC) cells. Thus, CD24 may be a promising therapeutic target for gastric cancer.