Mirzaei Mohammad Reza, Najafi Ali, Arababadi Mohammad Kazemi, Asadi Malek Hosein, Mowla Seyed Javad
Department of Molecular Genetics, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran.
Tumour Biol. 2014 Oct;35(10):9999-10009. doi: 10.1007/s13277-014-2238-9. Epub 2014 Jul 11.
OCT4B1 is a newly discovered spliced variant of OCT4 which is primarily expressed in pluripotent and tumor cells. Based on our previous studies, OCT4B1 is significantly overexpressed in tumors, where it endows an anti-apoptotic property to tumor cells. However, the mechanism by which OCT4B1 regulates the apoptotic pathway is not yet elucidated. Here, we investigated the effects of OCT4B1 suppression on the expression alteration of 84 genes involved in apoptotic pathway. The AGS (gastric adenocarcinoma), 5637 (bladder tumor), and U-87MG (brain tumor) cell lines were transfected with OCT4B1 or irrelevant siRNAs. The expression level of apoptotic genes was then quantified using a human apoptosis panel-PCR kit. Our data revealed an almost similar pattern of alteration in the expression profile of apoptotic genes in all three studied cell lines, following OCT4B1 suppression. In general, the expression of more than 54 apoptotic genes (64 % of arrayed genes) showed significant changes. Among these, some up-regulated (CIDEA, CIDEB, TNFRSF1A, TNFRSF21, TNFRSF11B, TNFRSF10B, and CASP7) and down-regulated (BCL2, BCL2L11, TP73, TP53, BAD, TRAF3, TRAF2, BRAF, BNIP3L, BFAR, and BAX) genes had on average more than tenfold gene expression alteration in all three examined cell lines. With some minor exceptions, suppression of OCT4B1 caused upregulation of pro-apoptotic and down-regulation of anti-apoptotic genes in transfected tumor cells. Uncovering OCT4B1 down-stream targets could further elucidate its part in tumorigenesis, and could lead to finding a new approach to combat cancer, based on targeting OCT4B1.
OCT4B1是新发现的OCT4剪接变体，主要在多能细胞和肿瘤细胞中表达。根据我们之前的研究，OCT4B1在肿瘤中显著过表达，赋予肿瘤细胞抗凋亡特性。然而，OCT4B1调节凋亡途径的机制尚未阐明。在此，我们研究了OCT4B1抑制对84个参与凋亡途径基因表达改变的影响。用OCT4B1或无关的小干扰RNA转染AGS（胃腺癌）、5637（膀胱肿瘤）和U - 87MG（脑肿瘤）细胞系。然后使用人凋亡检测板PCR试剂盒定量凋亡基因的表达水平。我们的数据显示，在所有三个研究的细胞系中，OCT4B1抑制后凋亡基因表达谱的改变模式几乎相似。总体而言，超过54个凋亡基因（占阵列基因的64%）的表达显示出显著变化。其中，一些上调基因（CIDEA、CIDEB、TNFRSF1A、TNFRSF21、TNFRSF11B、TNFRSF10B和CASP7）和下调基因（BCL2、BCL2L11、TP73、TP53、BAD、TRAF3、TRAF2、BRAF、BNIP3L、BFAR和BAX）在所有三个检测细胞系中的平均基因表达改变超过10倍。除了一些小的例外，OCT4B1的抑制导致转染肿瘤细胞中促凋亡基因上调和抗凋亡基因下调。揭示OCT4B1的下游靶点可能进一步阐明其在肿瘤发生中的作用，并可能导致基于靶向OCT4B1找到对抗癌症的新方法。
