Lo Lok Man, Raghunath Michael, Lee Kenneth K H
MOE Key Laboratory for Regenerative Medicine, School of Biomedical Sciences, Chinese University of Hong Kong.
Joint Chinese University of Hong Kong - University of Southampton Laboratory for Stem Cell and Regenerative Medicine, School of Biomedical Sciences, Chinese University of Hong Kong.
Adv Biosyst. 2019 Oct;3(10):e1900094. doi: 10.1002/adbi.201900094. Epub 2019 Aug 29.
Suspension spheroid cultures of anchorage-dependent cell types have been widely used in cancer and stem cell research, as well as for producing organoids. It is believed that the 3-dimensional spheroid presents cells with a more physiological microenvironment to grow so that they behave more like cells in vivo, which is lacking in conventional 2-dimensional monolayer cultures. Recently, it has been reported that cancer cells grown as spheroids could express stem cell-associated genes. Hence, it is investigated whether normal mouse and human fibroblasts cultured as spheroids could also be induced to express stem cell-associated genes. The transcriptomes of human fibroblasts cultured as a monolayer and spheroids are compared and analyzed using real-time RT-qPCR, RNA-sequencing, and bioinformatics. The results reveal that the spheroid transcriptome resemble somatic cells being reprogramed into stem cells, including the induced expression of stemness-associated genes, increased expression of mesenchymal-to-epithelial transition-associated genes, and decreased expression of epithelial-to-mesenchymal transition-associated genes. In this context, it is hypothesized that during the process of spheroid formation, matrix-cell signaling is lost in favor of cell-cell contact signaling and that this subsequently increases the activity of the PI3K/Akt pathway that then upregulates Tbdx3 and stemness-associated genes.
依赖贴壁的细胞类型的悬浮球体培养已广泛应用于癌症和干细胞研究以及类器官的生成。人们认为，三维球体为细胞提供了更接近生理状态的生长微环境，使它们的行为更像体内的细胞，而传统的二维单层培养则缺乏这种环境。最近，有报道称，以球体形式生长的癌细胞能够表达与干细胞相关的基因。因此，研究了作为球体培养的正常小鼠和人成纤维细胞是否也能被诱导表达与干细胞相关的基因。使用实时RT-qPCR、RNA测序和生物信息学对作为单层和球体培养的人成纤维细胞的转录组进行了比较和分析。结果表明，球体转录组类似于被重编程为干细胞的体细胞，包括干性相关基因的诱导表达、间充质向上皮转化相关基因的表达增加以及上皮向间充质转化相关基因的表达降低。在这种情况下，推测在球体形成过程中，基质-细胞信号传导丧失，转而有利于细胞-细胞接触信号传导，随后这增加了PI3K/Akt途径的活性，进而上调Tbdx3和干性相关基因。
