ABSTRACT
This study was purpose to investigate the effects of CD147 on the invasiveness of leukemia cells U937. The experiments were divided into 4 groups: control group, LPS group, CD147mAb group and LPS+CD147 mAb group. Cells were treated by lipopolysaccharide (LPS) or anti-CD147 monoclonal antibody, and the expression of CD147 and MMP-2, -9, the invasive potential of the cells in vitro and ex vivo, as well as the invasion of the implanted tumors in SCID mice were analysed by RT-PCR, FCM, gel zymography and invasion test in vitro respectively. The results showed that the expression of CD147 was elevated by the induction of LPS, and the enhanced expression of CD147 on U937 cells increased the production and secretion of MMP-2 and MMP-9 as measured by reverse transcription-PCR and gel zymography. An increased number of LPS-induced cells invading through a reconstituted basement membrane were observed by invasion assays. These responses were down-regulated after blocking CD147 with anti-CD147 antibody. At 30 days after intravenous injection of LPS pretreated U937 cells to SCID mice human U937 cells were found in the bone marrow and lung of the mice, indicating the invasion of the tumor cells. And overexpressions of CD147, MMP-2 and MMP-9 were found in the lung tissue of the mice injected with LPS-treated but not anti-CD147 antibody treated tumor cells. It is concluded that overexpression of CD147 on U937 cells may increase the secretion and activation of MMP-2 and MMP-9 and thus promote the invasiveness of the tumor cells.