Hao Shuai, Sun Suozhu, Xiao Xueyuan, He Dacheng, Liu Liyun
Beijing Engineering and Technology Research Center of Food Additives, Beijing Technology and Business University, Beijing, 100048, People's Republic of China.
Department of Pathology, General Hospital of the Second Artillery, Beijing, 100878, People's Republic of China.
J Mol Histol. 2016 Jun;47(3):239-47. doi: 10.1007/s10735-016-9666-3. Epub 2016 Mar 4.
Transthyretin (TTR) is expressed primarily in liver, choroid plexus of brain and pancreatic islet A and B cells. It is also synthesized in some endocrine tumors. In the present study, the protein expression of TTR in lung cancer tissues and cell lines was investigated by western blot. The mRNA expression of TTR in 24 pairs of frozen lung cancer tissues was examined by RT-PCR. The specific expression and cellular distribution of TTR were also evaluated in 104 paraffin-embedded lung cancer samples and 3 normal lung tissues by immunohistochemistry. Similarly, the subcellular localization and expression of TTR were further analyzed in lung cancer cell lines. With the exception of mucinous adenocarcinoma, the expression of TTR protein was observed in all tested subtypes of lung carcinoma. Adenocarcinoma displayed the highest positive expression rate of TTR, accounting for 84.4 %, and the positive expression rate of TTR was up to 85.7 % at stages III and IV. The secretory bubbles with strong TTR staining were observed in luminal cells of lung cancer. Furthermore, the localization of TTR in the cytoplasm of lung cancer cells and the secretion of TTR into extracellular milieu were also confirmed. Taken together, TTR is selectively synthesized in lung cancer cells and can be secreted extracellularly.
转甲状腺素蛋白(TTR)主要在肝脏、脑脉络丛以及胰岛A细胞和B细胞中表达。它也在一些内分泌肿瘤中合成。在本研究中,通过蛋白质免疫印迹法检测了肺癌组织和细胞系中TTR的蛋白表达。通过逆转录聚合酶链反应(RT-PCR)检测了24对冻存肺癌组织中TTR的mRNA表达。还通过免疫组织化学法评估了104例石蜡包埋肺癌样本和3例正常肺组织中TTR的特异性表达和细胞分布。同样,在肺癌细胞系中进一步分析了TTR的亚细胞定位和表达。除黏液腺癌外,在所有检测的肺癌亚型中均观察到TTR蛋白的表达。腺癌显示TTR的阳性表达率最高,占84.4%,在III期和IV期TTR的阳性表达率高达85.7%。在肺癌的管腔细胞中观察到有强TTR染色的分泌泡。此外,还证实了TTR在肺癌细胞胞质中的定位以及TTR分泌到细胞外环境中。综上所述,TTR在肺癌细胞中选择性合成并可分泌到细胞外。