Analysis of RECK (a novel MMP inhibitor) Expression and its Roles as a Biomarker and Evaluation of RECK as a Potential Therapeutic Agent for Osteosarcoma

Kim, Kap Jung; Kim, Han Soo; Kang, Hyun Guy; Oh, Joo Han; Lee, Sang Hoon; Lee, Sang Ki; Lee, Mi Ra

Abstract

PURPOSE
The purpose of this study is to analyze the mechanism of RECK gene (a novel MMP inhibitor) in human osteosarcoma and evaluation of RECK as a prognostic factor and therapeutic target.
MATERIALS AND METHODS
Osteosarcoma cell lines were established from tumor samples of 23 patients who had been treated from March 2003 to April 2004 and 4 standard cell lines (HOS, MG-63, SaOS-2, U-2OS). We isolated the RNA from 27 cell lines and evaluated the expression level of RECK gene using quantitative real time-PCR method. MMP-2 and MMP-9 expression were evaluated by gelatin zymography. Five cell lines were selected which had a statistical significance between RECK gene up-regulation and MMP expression (p=0.01). Then 5 cell lines and 3 standard cell lines were transfected by RECK gene. We compared RECK gene expression with MMP down-regulation between transfected cell lines and non-transfected cell lines. Invasion of transfected cell lines were evaluated by invasion assay using matrigel.
RESULTS
RECK genes were expressed in all cell lines and 1 cell line showed especially high expression. In zymography, pro-MMP-2 was expressed in almost cell lines whereas pro-MMP-9 was rarely expressed. RECK gene expressions were increasingly high and MMP expressions were low in transfected cell lines via zymography. Transfected HOS cells decreased invasiveness in matrigel invasion assay and showed small number of migrated cells. It had a statistical significance (p<0.01).
CONCLUSION
It is expected that down-regulation of MMP by RECK gene expression can be used as a biologic marker. It can be a new therapeutic strategies and valuable prognostic factors in treating osteosarcoma.