Analysis of transforming activity of human synovial sarcoma-associated chimeric protein SYT-SSX1 bound to chromatin remodeling factor hBRM/hSNF2 alpha.
Human synovial sarcoma has been shown to exclusively harbor the chromosomal translocation t(X;18) that produces the chimeric gene SYT-SSX. However, the role of SYT-SSX in cellular transformation remains unclear. In this study, we have established 3Y1 rat fibroblast cell lines that constitutively express SYT, SSX1, and SYT-SSX1 and found that SYT-SSX1 promoted growth rate in culture, anchorage-independent growth in soft agar, and tumor formation in nude mice. Deletion of the N-terminal 181 amino acids of SYT-SSX1 caused loss of its transforming activity. Furthermore, association of SYT-SSX1 with the chromatin remodeling factor hBRM/hSNF2 alpha, which regulates transcription, was demonstrated in both SYT-SSX1-expressing 3Y1 cells and in the human synovial sarcoma cell line HS-SY-II. The binding region between the two molecules was shown to reside within the N-terminal 181 amino acids stretch (aa 1--181) of SYT-SSX1 and 50 amino acids (aa 156--205) of hBRM/hSNF2 alpha and we found that the overexpression of this binding region of hBRM/hSNF2 alpha significantly suppressed the anchorage-independent growth of SYT-SSX1-expressing 3Y1 cells. To analyze the transcriptional regulation by SYT-SSX1, we established conditional expression system of SYT-SSX1 and examined the gene expression profiles. The down-regulation of potential tumor suppressor DCC was observed among 1,176 genes analyzed by microarray analysis, and semi-quantitative reverse transcription--PCR confirmed this finding. These data clearly demonstrate transforming activity of human oncogene SYT-SSX1 and also involvement of chromatin remodeling factor hBRM/hSNF2 alpha in human cancer.
Laboratory of Molecular and Cellular Pathology, Hokkaido University School of Medicine, N 15, W7, Kita-ku, Sapporo 060-8638, Japan.
M
M
Nagai
S
S
Tanaka
M
M
Tsuda
S
S
Endo
H
H
Kato
H
H
Sonobe
A
A
Minami
H
H
Hiraga
H
H
Nishihara
H
H
Sawa
K
K
Nagashima
D000362:Agar; D000818:Animals; D015815:Cell Adhesion Molecules / Q000235:genetics / Q000378:metabolism; D002460:Cell Line; D002843:Chromatin / Q000502:physiology; D000075389:DCC Receptor; D004265:DNA Helicases; D004252:DNA Mutational Analysis; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D015536:Down-Regulation; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D006801:Humans; D009687:Nuclear Proteins; D015514:Oncogene Proteins, Fusion / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D011956:Receptors, Cell Surface; D013584:Sarcoma, Synovial / Q000473:pathology; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014407:Tumor Cells, Cultured; D025521:Tumor Suppressor Proteins
D015815:Cell Adhesion Molecules; D002843:Chromatin; D000075389:DCC Receptor; C501909:DCC protein, human; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D015514:Oncogene Proteins, Fusion; D011956:Receptors, Cell Surface; C084011:SMARCA2 protein, human; C116512:SYT-SSX fusion protein; D014157:Transcription Factors; D025521:Tumor Suppressor Proteins; D000362:Agar; C084108:SMARCA4 protein, human; D004265:DNA Helicases