Abstract 160: Role of EMMPRIN in osteosarcoma metastases
Authors: Han Ilkyu , Kim Ha Jung , Kim Han-Soo 
Published: August 2019

Abstract
Introduction: Although the survival rate of localized osteosarcoma patients has increased, patients with metastasis carry a poor prognosis. Thus, identification of factors contributing to metastatic progression is required. Extracellular matrix metalloproteinase inducer (EMMPRIN) is a cell-surface glycoprotein which plays multiple roles in physiologic and pathologic conditions. EMMPRIN stimulates adjacent stromal cells or tumor cells to produce matrix metalloproteinase (MMP) and is highly expressed in multiple cancer types. EMMPRIN also stimulates expression of vascular endothelial growth factor (VEGF) which leads to angiogenesis. However, the expression and role of EMMRPIN in osteosarcoma have never been studied. This study was performed 1) to investigate the expression of EMMPRIN in osteosarcoma and 2) to examine if EMMPRIN, via tumor-stroma interaction, is associated with metastatic potential in osteosarcoma. Methods: Level of EMMPRIN mRNA expression was evaluated by RT-PCR in 6 tumor-derived osteosarcoma cell lines and by immunohistochemistry prechemotherapy biopsies from 52 patients. Clinical data of these patients were reviewed to examine the association of EMMPRIN expression and clinical outcome. Transfection of EMMPRIN-targeting siRNA in SaOS-2 cell line was performed to examine the role of EMMPRIN in osteosarcoma progression. To study the role of EMMPRIN in tumor-stromal interaction, co-culture of SaOS-2 with osteoblast (hFOB) was experimented. Functional in vitro assays that reflect metastatic potential of osteosarcoma cells were performed. MMP production, VEGF production, cell invasion and proliferation were studied by gelatin zymography, VEGF ELISA, Matrigel invasion assay and WST-1 assay, respectively. Results: EMMPRIN was expressed in 90% by immunohistochemistry with strong accentuation along the cell membrane. Level of EMMRIN mRNA expression was significantly higher in 5 of 6 tumor-derived cell lines compared to MG63. Patients with high EMMPRIN expression had significantly worse metastasis-free survival. EMMPRIN mRNA levels was significantly down-regulated by siRNA transfection compared to control-siRNA transfected cell. Co-culture of osteoblast and SaOS-2 enhanced stimulation of pro-MMP2. This stimulation was reversed by transfection of SaOS-2 with EMMPRIN-targeting siRNA. Number of cells crossing the chamber was statistically lower in EMMPRIN-siRNA transfected cells. When osteoblast and SaOS-2 were co-cultured, VEGF expression was increased compared to SaOS-2 only culture. EMMPRIN-targeting siRNA transfection resulted in decrease of VEGF expression. SaOS-2 cells transfected with EMMPRIN-siRNA showed decreased proliferation potential compared to control-siRNA transfected cells. Conclusion: Our data suggest that highly expressed EMMPRIN plays an important role in metastatic progression of osteosarcoma. EMMPRIN could serve as a potential therapeutic target in osteosarcoma.
Citation Format: Ilkyu Han, Ha Jung Kim, Han-Soo Kim. Role of EMMPRIN in osteosarcoma metastases [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 160.