Identification of an active site of EMMPRIN for the augmentation of matrix metalloproteinase-1 and -3 expression in a co-culture of human uterine cervical carcinoma cells and fibroblasts.

OBJECTIVE: Extracellular matrix metalloproteinase inducer (EMMPRIN) is highly expressed on malignant tumor cell surface and accelerates tumor invasion. We previously reported that human uterine cervical carcinoma SKG-II cells exhibit the progression of in-vitro invasiveness by utilizing the enhanced production of matrix metalloproteinase (MMP) in human uterine cervical fibroblasts (HUCF) under an in-vitro co-culture model (Sato T et al., Gynecol Oncol 2004; 92:47-56). The aim of this study was to clarify the active site of EMMPRIN in the augmentation of MMP production in the co-culture of SKG-II cells and HUCF.
METHODS: Western and Northern blot analyses were used to examine EMMPRIN and MMP expression in a co-culture of SKG-II cells or EMMPRIN-transfected COS-7 cells and HUCF. A systematic peptide screening method using nine synthetic EMMPRIN peptides was used to identify active site(s) of EMMPRIN for MMP induction.
RESULTS: SKG-II cells constitutively expressed 53-kDa EMMPRIN on the cell surface and EMMPRIN production was enhanced under the co-culture. The concomitant augmentation of proMMP-3 production was diminished by adding an EMMPRIN antibody. EMMPRIN-transfected COS-7 cells stimulated HUCF to predominantly augment proMMP-1 and -3 expressions. A systematic peptide screening method revealed that (42)SLNDSATEVTGHRWLK(57) in the first loop domain of EMMPRIN participated in the augmentation of proMMP-1 production.
CONCLUSIONS: These results provide a novel mechanism of malignancy of uterine cervical carcinoma, in that the augmentation of EMMPRIN expression by tumor-stromal cell interaction progresses tumor invasion along with the increase of MMP expression via an active site of EMMPRIN, (42)SLNDSATEVTGHRWLK(57).