Analysis of transforming activity of human synovial sarcoma-associated chimeric protein SYT-SSX1 bound to chromatin remodeling factor hBRM/hSNF2α
Analysis of transforming activity of human synovial sarcoma-associated chimeric protein SYT-SSX1 bound to chromatin remodeling factor hBRM/hSNF2α
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DOI：
10.1073/pnas.061036798
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发表时间：
2001-03-27
影响因子：
11.1
通讯作者：
Nagashima, K
中科院分区：
文献类型：
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作者：
Nagai, M;Tanaka, S;Nagashima, K
人类滑膜肉瘤已被证明仅含有染色体易位t(X；18)，该易位产生嵌合基因SYT-SSX。然而，SYT-SSX在细胞转化中的作用尚不清楚。在本研究中，我们建立了组成表达SYT、SSX1和SYT-SSX1的3Y1大鼠成纤维细胞系，发现SYT-SSX1促进了培养中的生长速度、软琼脂中的贴壁非依赖性生长和裸鼠体内的肿瘤形成。SYT-SSX1 N端181个氨基酸缺失导致其转化活性丧失。此外，SYT-SSX1与调节转录的染色质重塑因子hBRM/hSNF2α在表达SYT-SSX1的3Y1细胞和人滑膜肉瘤细胞系HS-SY-II中都被证实存在关联。这两个分子之间的结合区位于SYT-SSX1的N端181个氨基酸(aA1-181)和hBRM/hSNF2α的50个氨基酸(a156-205)之间，我们发现hBRM/hSNF2α的这个结合区的过表达显著抑制了SYT-SSX1表达的3Y1细胞的非锚定生长。为了分析SYT-SSX1的转录调控，我们建立了SYT-SSX1的条件表达系统，并检测了其基因表达谱。在芯片分析的1,176个基因中观察到潜在的肿瘤抑制基因DCC的下调，半定量逆转录-聚合酶链式反应证实了这一发现。这些数据清楚地表明人类癌基因SYT-SSX1的转化活性以及染色质重塑因子hBRM/hSNF2α在人类癌症中的参与。
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.