MedStar Georgetown Orthopaedic Institute, 110 Irving Street, NW C-2173, Washington, DC, 20010, USA,
Clin Orthop Relat Res. 2014 Mar;472(3):874-82. doi: 10.1007/s11999-013-3065-9.
Most synovial sarcomas contain a chromosomal translocation t(X;18), which results in the formation of an oncoprotein SS18-SSX critical to the viability of synovial sarcoma.
QUESTIONS/PURPOSES: We (1) established and characterized three novel synovial sarcoma cell lines and asked (2) whether inhibition of SS18-SSX1 decreases cell viability in these cell lines; and (3) whether reduction in viability after SS18-SSX1 knockdown is caused by apoptosis. After identifying a specific posttranscriptional splice variant in our cell lines, we asked (4) whether this provides a survival benefit in synovial sarcoma.
Cells lines were characterized. SS18-SSX1 knockdown was achieved using a shRNA system. Cell viability was assessed by WST-1 analysis and apoptosis examined by caspase-3 activity.
We confirmed the SS18-SSX1 translocation in all cell lines and identified a consistent splicing variant. We achieved successful knockdown of SS18-SSX1 and with this saw a significant reduction in cell viability. Decreased viability was a result of increased apoptosis. Reintroduction of the exon 8 sequence into cells reduced cell viability in all cell lines.
We confirmed the presence of the SS18-SSX1 translocation in our cell lines and its importance in the survival of synovial sarcoma. We have also demonstrated that reduction in cell viability is related to an increase in apoptosis. In addition, we have identified a potential mediator of SS18-SSX function in exon 8.
SS18-SSX represents a tumor-specific target in synovial sarcoma. Exploitation of SS18-SSX and its protein partners will allow us to develop potent tumor-specific therapeutic agents.
大多数滑膜肉瘤都包含一个染色体易位 t(X;18)，导致形成一个对滑膜肉瘤存活至关重要的癌蛋白 SS18-SSX。
问题/目的：我们（1）建立并鉴定了三个新型滑膜肉瘤细胞系，并询问（2）抑制 SS18-SSX1 是否会降低这些细胞系中的细胞活力；以及（3）在 SS18-SSX1 敲低后活力降低是否是由细胞凋亡引起的。在我们的细胞系中鉴定出一个特定的转录后剪接变体后，我们询问（4）这是否为滑膜肉瘤提供了生存优势。
对细胞系进行了鉴定。使用 shRNA 系统实现 SS18-SSX1 敲低。通过 WST-1 分析评估细胞活力，通过 caspase-3 活性检测凋亡。
我们在所有细胞系中均证实了 SS18-SSX1 易位，并鉴定出一个一致的剪接变体。我们成功地实现了 SS18-SSX1 的敲低，随之而来的是细胞活力的显著降低。活力降低是细胞凋亡增加的结果。将外显子 8 序列重新引入细胞后，所有细胞系的细胞活力均降低。
我们证实了我们的细胞系中存在 SS18-SSX1 易位及其在滑膜肉瘤存活中的重要性。我们还证明了细胞活力的降低与细胞凋亡的增加有关。此外，我们已经确定了外显子 8 中 SS18-SSX 功能的潜在介质。
SS18-SSX 是滑膜肉瘤的肿瘤特异性靶标。对 SS18-SSX 及其蛋白伴侣的利用将使我们能够开发出有效的肿瘤特异性治疗药物。
