Sato Mitsuo, Shay Jerry W, Minna John D
Dept. of Pathophysiological Laboratory Sciences Nagoya University Graduate School of Medicine, 1-1-20 Daiko-minami, Higashi-ku, Nagoya, 461-8673, Japan.
Dept. of Cell Biology, University of Texas Southwestern Medical Center, Dallas, 5323 Harry Hines Blvd, Dallas, TX 75390, USA.
Respir Investig. 2020 Sep;58(5):344-354. doi: 10.1016/j.resinv.2020.04.005. Epub 2020 Jun 22.
Primary cultures of human lung epithelial cells are ideal representatives of normal lung epithelial cells, and while there are certain novel approaches for the long-term culture of lung epithelial cells, the cells eventually undergo irreversible growth arrest, limiting their experimental utility, particularly the ability to widely distribute these cultures and their clonal derivatives to the broader research community. Therefore, the establishment of immortalized normal human lung epithelial cell strains has garnered considerable attention. The number and type of oncogenic changes necessary for the tumorigenic transformation of normal cells could be determined using "normal" cell lines immortalized with the simian virus 40 (SV40) large T antigen (LT). A primary report suggested that LT, human telomerase reverse transcriptase (hTERT), and oncogenic RAS transformed normal lung epithelial cells into tumorigenic cells. Since LT inactivates the tumor suppressors p53 and RB, at least four alterations would be necessary. However, the SV40 small T antigen (ST), a different oncoprotein, was also introduced simultaneously with LT in the above-mentioned study. Furthermore, the possible uncharacterized functions of LT remained largely obscure. Therefore, no definitive conclusion could be arrived in these studies. Subsequent studies used methods that did not involve the use of oncoproteins and revealed that at least five genetic changes were necessary for full tumorigenic transformation. hTERT-immortalized normal human lung epithelial cell lines established without using viral oncoproteins were also used for investigating several aspects of lung cancer, such as epithelial to mesenchymal transition and the cancer stem cell theory. The use of immortalized normal lung epithelial cell models has improved our understanding of lung cancer pathogenesis and these models can serve as valuable research tools.
人肺上皮细胞的原代培养是正常肺上皮细胞的理想代表，虽然存在某些用于肺上皮细胞长期培养的新方法，但这些细胞最终会经历不可逆的生长停滞，限制了它们的实验效用，特别是将这些培养物及其克隆衍生物广泛分发给更广泛研究群体的能力。因此，永生化正常人肺上皮细胞系的建立引起了相当大的关注。使用用猴病毒40（SV40）大T抗原（LT）永生化的“正常”细胞系，可以确定正常细胞致瘤转化所需的致癌变化的数量和类型。一份初步报告表明，LT、人端粒酶逆转录酶（hTERT）和致癌性RAS可将正常肺上皮细胞转化为致瘤细胞。由于LT会使肿瘤抑制因子p53和RB失活，因此至少需要四种改变。然而，在上述研究中，SV40小T抗原（ST），一种不同的癌蛋白，也与LT同时被引入。此外，LT可能未被表征的功能在很大程度上仍然不清楚。因此，这些研究无法得出明确的结论。随后的研究使用了不涉及癌蛋白的方法，并表明完全致瘤转化至少需要五种基因变化。未使用病毒癌蛋白建立的hTERT永生化正常人肺上皮细胞系也被用于研究肺癌的几个方面，如上皮-间质转化和癌症干细胞理论。永生化正常肺上皮细胞模型的使用增进了我们对肺癌发病机制的理解，这些模型可作为有价值的研究工具。
