Pramoonjago P, Baras A S, Moskaluk C A
Department of Pathology and Biochemistry, University of Virginia, Charlottesville, VA 22908, USA.
Oncogene. 2006 Sep 14;25(41):5626-39. doi: 10.1038/sj.onc.1209566. Epub 2006 Apr 24.
Microarray RNA gene expression profiling analysis has shown that Sox4 (Sry-related high mobility group (HMG) box 4) is one of the most upregulated genes in adenoid cystic carcinoma (ACC), relative to non-neoplastic tissue of origin. Here, we show that Sox4 protein is similarly upregulated in ACC by immunohistochemistry of 28 primary cancers and 20 normal tissues. To elucidate the functional significance of these findings, RNA interference (RNAi)-mediated RNA silencing was used to downregulate Sox4 expression in the ACC-derived cell line, ACC3. With confirmed knockdown of Sox4 protein, cell viability was reduced by 51%, with a corresponding increase of apoptosis to 85% as compared to 12% in controls. Apoptosis was confirmed by cell morphology, DNA fragmentation and flow cytometry. Cells could be rescued from the proapoptotic effects of Sox4 RNAi by co-transfection with a construct expressing functional Sox4. Microarray gene expression profiling of RNAi knockdown experiments shows that downregulation of Sox4-modulated expression of critical genes involved in apoptosis and cell cycle control. Overall, our findings suggest that Sox4 contributes to the malignant phenotype of ACC cells by promoting cell survival.
微阵列RNA基因表达谱分析表明，相对于起源的非肿瘤组织，Sox4（性别决定区Y相关高迁移率族（HMG）盒4）是腺样囊性癌（ACC）中上调最为明显的基因之一。在此，我们通过对28例原发性癌症和20例正常组织进行免疫组织化学检测发现，Sox4蛋白在ACC中同样上调。为阐明这些发现的功能意义，我们利用RNA干扰（RNAi）介导的RNA沉默技术下调ACC来源的细胞系ACC3中Sox4的表达。在确认Sox4蛋白被敲低后，细胞活力降低了51%，与之相应的是，细胞凋亡率增至85%，而对照组的凋亡率为12%。通过细胞形态学、DNA片段化分析和流式细胞术证实了细胞凋亡。通过共转染表达功能性Sox4的构建体，可使细胞从Sox4 RNAi的促凋亡效应中得到挽救。RNAi敲低实验的微阵列基因表达谱显示，Sox4的下调可调节参与细胞凋亡和细胞周期调控的关键基因的表达。总体而言，我们的研究结果表明，Sox4通过促进细胞存活，促成了ACC细胞的恶性表型。
