Establishment and characterization of a new synovial sarcoma cell line, SN-SY-1: special reference to bcl-2 protein and SYT-SSX1 hybrid transcripts.

We established and characterized a new human synovial sarcoma cell line, SN-SY-1, derived from a monophasic fibrous synovial sarcoma excised from the abdominal wall of a 21-year-old man. We maintained the cell line for over 35 passages in vitro. The SN-SY-1 cells in vitro exhibit spindle and polygonal shapes and join to form an epithelial plaque. SN-SY-1 maintained a consistent karyotype: 46,t(X;18)(p11.2;q11.2), Y, t(6;8) (q13-15;q11-13), the same as that of the primary tumor specimen. RT-PCR assay for chimeric SYT-SSX transcripts followed by digestion with restriction enzymes revealed SYT-SSX1 fusion protein. An immunohistochemical study revealed expression of bcl-2 protein in the SN-SY-1 cell line, in vitro and in vivo. However, DNA analysis showed no rearrangement of the bcl-2 gene, and expression of bcl-2 mRNA was low. Why bcl-2 protein was expressed in this synovial sarcoma was not clarified.