Satoh Hiroaki, Ishikawa Hiroichi, Kamma Hiroshi, Fujiwara Masachika, Homma Shinsuke, Kagohashi Katsunori, Ohtsuka Morio, Sekizawa Kiyohisa
Division of Respiratory Medicine, Institute of Clinical Medicine, University of Tsukuba, Tsukuba-city, Ibaraki 305-8575, Japan.
Int J Mol Med. 2004 Oct;14(4):605-8.
The overexpression of heterogeneous nuclear ribonucleoprotein (hnRNP) A2/B1, especially of B1 has been reported informative to detect pre-clinical lung cancer for early detection. However, relatively little work has been performed on the expression of hnRNP A2/B1 in non-malignant airway cells; such information is clearly required to investigate whether overexpression of this protein could be a specific marker for early lung cancer detection. In order to evaluate whether the expression of hnRNP A2/B1 is specific for cancer cells, we investigated the expression of the protein in human small airway epithelial (HSAE) cells. Using immunostaining and Western blotting with monoclonal antibodies, 4G8 (specifically reacts A2) and 2B2 (specific to B1), expression of hnRNP A2/B1 in HSAE cells was evaluated. Northern blotting and quantitative RT-PCR were also performed. In HSAE cells, hnRNP A2 as well as B1 were expressed primarily in the nucleus excluding the nucleolus, although the expression of A2 protein was weaker than that of B1 protein. Staining pattern of hnRNP A2/B1 in HSAE cells was similar to that observed in control cancer cells. Western blotting with 4G8 and 2B2 apparently demonstrated expression of A2 and B1 in HSAE cells. In Northern blotting, both hnRNP A2 mRNA and B1 mRNA were observed in HSAE cells as shown in control cancer cells. hnRNP A2/B1 was apparently expressed in HSAE cells, although the expression in HSAE cells was weaker than that of cancer cells. More quantitative determination of A2/B1 is required to elucidate their significance in early lung cancer detection.
据报道，异质性核核糖核蛋白（hnRNP）A2/B1的过表达，尤其是B1的过表达，对临床前肺癌的早期检测具有参考价值。然而，关于hnRNP A2/B1在非恶性气道细胞中的表达研究相对较少；显然需要此类信息来研究该蛋白的过表达是否可能是早期肺癌检测的特异性标志物。为了评估hnRNP A2/B1的表达是否对癌细胞具有特异性，我们研究了该蛋白在人小气道上皮（HSAE）细胞中的表达。使用单克隆抗体4G8（特异性识别A2）和2B2（特异性识别B1）进行免疫染色和蛋白质印迹分析，评估hnRNP A2/B1在HSAE细胞中的表达。同时进行了Northern印迹分析和定量逆转录聚合酶链反应（RT-PCR）。在HSAE细胞中，hnRNP A2和B1主要在细胞核中表达，但不包括核仁，尽管A2蛋白的表达弱于B1蛋白。HSAE细胞中hnRNP A2/B1的染色模式与对照癌细胞中观察到的相似。用4G8和2B2进行的蛋白质印迹分析明显显示HSAE细胞中存在A2和B1的表达。在Northern印迹分析中，与对照癌细胞一样，在HSAE细胞中观察到了hnRNP A2 mRNA和B1 mRNA。hnRNP A2/B1在HSAE细胞中明显表达，尽管其在HSAE细胞中的表达弱于癌细胞。需要对A2/B1进行更定量的测定，以阐明它们在早期肺癌检测中的意义。
