Lin Ta-Chin, Wang Kai-Hung, Chuang Kuo-Hsiang, Kao An-Pei, Kuo Tsung-Cheng
Department of Obstetrics and Gynecology, Kuo General Hospital, Tainan, Taiwan; Center for Reproductive Medicine, Kuo General Hospital, Tainan, Taiwan.
Department of Obstetrics and Gynecology, Kuo General Hospital, Tainan, Taiwan; Center for Reproductive Medicine, Kuo General Hospital, Tainan, Taiwan; Department of Laboratory Medicine, Kuo General Hospital, Tainan, Taiwan.
Taiwan J Obstet Gynecol. 2023 Jan;62(1):16-21. doi: 10.1016/j.tjog.2022.08.014.
Research has suggested that tumor-initiating tumor stem cells are derived from normal stem cells and that tumor cells undergo progressive de-differentiation to achieve a stem cell-like state. Tumor stem cells are characterized by high proliferation ability, high plasticity, expression of multi-drug resistance proteins, and the ability to seed new tumors. Octamer-binding transcription factor 4 (Oct-4) and its activation targets are overexpressed in the tumor stem cells of various types of tumors, and this expression is associated with the pathogenesis, development, and poor prognosis of tumors. The primary objective of this study was to test if a stably transfected with Oct-4 gene cell line, RL95-2/Oct-4, has the characteristics of tumor stem cells.
Human endometrial carcinoma cells (RL95-2) were transfected with a plasmid carrying genes for Oct-4 and green fluorescent protein (GFP). The stably transfected cells, RL95-2/Oct-4, were selected using G418 and observed to express the GFP reporter gene under the control of the Oct-4 promoter. GFP expression levels of RL95-2/Oct-4 cells were measured using flow cytometry. The proliferation potential of cells was determined according to cumulative population doubling and colony-formation efficiency. Gene expression was analyzed using reverse transcription-polymerase chain reaction.
RL95-2/Oct-4 cells not only exhibited increased expression of the three most important stem cell genes, Oct-4, Nanog, and Sox2, but also had increased expression of the endometrial tumor stem cell genes CD133 and ALDH1. Furthermore, enhanced expression of these genes in the RL95-2/Oct-4 cells was associated with higher colony-forming ability and growth rate than in parental RL95-2 cells. We also observed that cisplatin induced less cell death in RL95-2/Oct-4 cells than in RL95-2 cells, indicating that RL95-2/Oct-4 cells were more resistant to chemotherapeutic agents.
The study findings contribute to investigate the effects of Oct-4 on tumor stem cell origins.
研究表明，肿瘤起始肿瘤干细胞源自正常干细胞，肿瘤细胞经历渐进性去分化以达到干细胞样状态。肿瘤干细胞的特征在于高增殖能力、高可塑性、多药耐药蛋白的表达以及形成新肿瘤的能力。八聚体结合转录因子4（Oct-4）及其激活靶点在各种类型肿瘤的肿瘤干细胞中过表达，且这种表达与肿瘤的发病机制、发展及不良预后相关。本研究的主要目的是测试稳定转染Oct-4基因的细胞系RL95-2/Oct-4是否具有肿瘤干细胞的特征。
用人子宫内膜癌细胞（RL95-2）转染携带Oct-4和绿色荧光蛋白（GFP）基因的质粒。使用G418筛选稳定转染的细胞RL95-2/Oct-4，并观察其在Oct-4启动子控制下表达GFP报告基因。用流式细胞术测量RL95-2/Oct-4细胞的GFP表达水平。根据累积群体倍增和集落形成效率确定细胞的增殖潜能。用逆转录-聚合酶链反应分析基因表达。
RL95-2/Oct-4细胞不仅表现出三种最重要的干细胞基因Oct-4、Nanog和Sox2的表达增加，而且子宫内膜肿瘤干细胞基因CD133和ALDH1的表达也增加。此外，与亲本RL95-2细胞相比，RL95-2/Oct-4细胞中这些基因的表达增强与更高的集落形成能力和生长速率相关。我们还观察到，顺铂诱导RL95-2/Oct-4细胞死亡的程度低于RL95-2细胞，表明RL95-2/Oct-4细胞对化疗药物更具抗性。
该研究结果有助于探究Oct-4对肿瘤干细胞起源的影响。
