Abstract 1505: GATA3 expression is associated with poor differentiation of osteosarcoma cells

Abstract Objective: GATA3, a transcriptional factor promoting differentiation of Th2 cells, was expressed in breast cancer cells or bladder cancer cells. We reported that Gata3 expression in soft tissue sarcoma is an independent factor for poor prognosis. However, the role of GATA3 in osteosarcoma is unknown. We investigated whether GATA3 expression is associated with cell differentiation or clinical prognosis of osteosarcoma. Methods: We examined whether decreased GATA3 expression in MG63 osteosarcoma cells by induction of siRNA GATA3 using electroporation affects cell differentiation. We also evaluated GATA3 expression in biopsy samples of 31 osteosarcoma cases using immunohistochemical analysis, and statistically compared clinicopathological characteristics of GATA3-positive and GATA3-negative cases. In particular, the correlation between osteoid formation and GATA3 expression was examined. Result: GATA3 expression was observed in MG63 cells by Western blotting and real-time PCR. Decreased GATA3 expression caused by induction of siRNA promoted the expression of the osteoblast differentiation markers; osteopontin, osteocalcin and RUNX2; in MG63 cells, while ALP and DMP-1, pre-osteocyte markers, had not increased. The expression of p21, one of the differentiation markers of osteosarcoma, is also elevated by decreased GATA3 expression. GATA3 significantly expressed in osteosarcoma cases with less osteoid formation (P<0.001), although no significant correlation between GATA3 expression and clinical prognosis was observed. Conclusion: These data indicated that GATA3 expression might be associated with poor differentiation of osteosarcoma cells. GATA3 may be a target to treat for osteosarcoma through promotion of cell differentiation. Citation Format: Koji Hiraoka. GATA3 expression is associated with poor differentiation of osteosarcoma cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1505.