Han Rong-Fei, Ji Xiang, Dong Xing-Gao, Xiao Rui-Jing, Liu Yan-Ping, Xiong Jie, Zhang Qiu-Ping
Department of Immunology, Wuhan University School of Basic Medical Science, Wuhan, China E-mail :
Asian Pac J Cancer Prev. 2014;15(10):4271-4. doi: 10.7314/apjcp.2014.15.10.4271.
The epithelial to mesenchymal transition (EMT) is a key step during embryonic morphogenesis and plays an important role in drug resistance and metastasis in diverse solid tumors. We previously reported that 48 h treatment of anti-cancer drug doxorubicin could induce EMT in human gastric cancer BGC-823 cells. However, the long term effects of this transient drug treatment were unknown. In this study we found that after 48 h treatment with 0.1 μg/ml doxorubicin, most cells died during next week, while a minor population of cells survived and formed colonies. We propagated the surviving cells in drug free medium and found that these long term cultured drug survival cells (abbreviated as ltDSCs) retained a mesenchymal-like cell morphology, and expressed high levels of EMT-related molecules such as vimentin, twist and β-catenin. The expression of chromatin reprogramming factors, Oct4 and c-myc, were also higher in ltDSCs than parental cells. We further demonstrated that the protein level of p300 was upregulated in ltDSCs, and inhibition of p300 by siRNA suppressed the expression of vimentin. Moreover, the ltDSCs had higher colony forming ability and were more drug resistant when compared to parental cells. Our results suggested that an epigenetic mechanism is involved in the EMT of ltDSCs.
上皮-间质转化（EMT）是胚胎形态发生过程中的关键步骤，在多种实体瘤的耐药性和转移中发挥重要作用。我们之前报道过，抗癌药物阿霉素处理48小时可诱导人胃癌BGC-823细胞发生EMT。然而，这种短暂药物处理的长期影响尚不清楚。在本研究中，我们发现用0.1μg/ml阿霉素处理48小时后，大多数细胞在接下来的一周内死亡，而少数细胞存活并形成集落。我们在无药物培养基中培养存活细胞，发现这些长期培养的药物存活细胞（简称为ltDSCs）保留了间充质样细胞形态，并高表达EMT相关分子，如波形蛋白、Twist和β-连环蛋白。染色质重编程因子Oct4和c-myc在ltDSCs中的表达也高于亲本细胞。我们进一步证明，ltDSCs中p300的蛋白水平上调，用小干扰RNA抑制p300可抑制波形蛋白的表达。此外，与亲本细胞相比，ltDSCs具有更高的集落形成能力和更强的耐药性。我们的结果表明，一种表观遗传机制参与了ltDSCs的EMT过程。
