Absence of OCT4 expression in somatic tumor cell lines
Absence of OCT4 expression in somatic tumor cell lines
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DOI：
10.1634/stemcells.2007-0657
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发表时间：
2008-01-01
期刊：
影响因子：
5.2
通讯作者：
Schoeler, Hans R.
中科院分区：
文献类型：
--
作者：
Cantz, Tobias;Key, Goeran;Schoeler, Hans R.
POU结构域转录因子OCT 4与包括植入前胚胎的内细胞团的细胞的多能状态相关，并且已知在维持胚胎干细胞的多能性中起关键作用。OCT 4表达的再激活被假定发生在已经经历致癌或肿瘤形成的分化细胞中。与早期的研究相反，最近的报道描述了OCT 4在几种人类肿瘤细胞系中的表达。为了解决早期和最近研究之间OCT 4表达的明显差异，我们通过免疫荧光、Western印迹和RT-PCR分析确定了OCT 4在宫颈癌细胞系HeLa和乳腺癌细胞系MCF 7中的表达，并与人畸胎瘤细胞系nTera进行了比较。我们无法检测染色的OCT 4转录因子在HeLa和MCF 7细胞的细胞核中的免疫荧光使用两种不同的单克隆抗体。在HeLa和MCF 7细胞中观察到微弱的细胞质染色;然而，通过Western印迹分析未检测到OCT 4信号。此外，我们无法检测到显着水平的OCT 4 mRNA在HeLa细胞和MCF 7细胞通过RT-PCR。此外，OCT 4启动子区在HeLa和MCF 7细胞中高度甲基化。我们认为，最近的报告中的OCT 4表达在这些和其他癌细胞系实际上可以归因于OCT 4假基因表达或误解的背景信号在免疫荧光实验。总之，我们强调，需要充分的控制，在调查中的OCT 4在体细胞系的表达，免疫荧光和RT-PCR。
The POU-domain transcription factor OCT4 is associated with the pluripotent state of cells comprising the inner cell mass of pre-implantation embryos and has been known to play a critical role in the maintenance of pluripotency of embryonic stem cells. Reactivation of OCT4 expression is postulated to occur in differentiated cells that have undergone carcinogenesis, or tumor formation. In contrast to earlier studies, recent reports describe OCT4 expression in several human tumor cell lines. To resolve the apparent discrepancy in OCT4 expression between earlier and recent studies, we determined OCT4 expression in the cervical carcinoma cell line HeLa and the breast cancer cell line MCF7 in comparison with the human teratoma cell line nTera by immunofluorescence, Western blot, and RT-PCR analyses. We were unable to detect staining of the OCT4 transcription factor in the nucleus of HeLa and MCF7 cells by immunofluorescence using two different monoclonal antibodies. Faint cytoplasmic staining in HeLa and MCF7 cells was observed; however, no OCT4 signal could be detected by Western blot analysis. In addition, we were unable to detect significant levels of OCT4 mRNA in HeLa and in MCF7 cells by RT-PCR. Furthermore, the OCT4 promoter region is highly methylated in HeLa and MCF7 cells. We argue that recent reports of OCT4 expression in these and other cancer cell lines could actually be attributed to OCT4 pseudogene expression or misinterpretation of background signals in immunofluorescence experiments. In conclusion, we emphasize the need for adequate controls in investigations of OCT4 expression in somatic cell lines by immunofluorescence and RT-PCR.