The analysis of genomic point mutations is one of the research strategies to explore the clonal evolution of tumor cells. At present, clonal evolution of tumor cells is mainly determined by bulk sampling and sequencing of different sections of the tumor. Since this approach analyzes a mixture of different cell types, it may not accurately represent the clonal evolution of specific tumor cell populations and likely miss low frequency mutations, especially when the sequencing depths are not sufficient. To address this issue, we have developed a strategy to analyze genomic point mutations from prostate basal cell carcinoma (BCC) tissues at single-cell resolution. Firstly, we optimized the single-cell whole genome amplification procedure with HepG2 cells. Then the single cells from BCC tissue were captured by a microfluidic chip of Fluidigm and processed for whole-genome amplification. Both SCUBE3 and MST1L genomic mutations were obtained by whole exome sequencing. Finally, we examined the genomic mutations through single-cell targeted amplification and Sanger sequencing. The established method successfully reconfirmed the mutations of SCUBE3 and MST1L in BCC at single cell level. The strategy established in this study could provide a useful tool for determining the clonal evolution of tumor cells based on genomic mutations at single-cell resolution.
分析基因碱基突变是探究肿瘤细胞克隆演化的研究方法之一。目前,常取组织不同区域的群体细胞测序,基于群体水平的基因碱基突变频率等信息绘制出肿瘤的克隆演化过程。但是,该方法易遗失低频突变,并且组织群体细胞类型不单一,不能代表特定细胞群体的克隆演化过程。本研究以前列腺基底细胞癌(prostate basal cell carcinoma, BCC)为例,建立了一种探究肿瘤单细胞的基因碱基突变方法,实现了基于单细胞基因碱基突变分析肿瘤细胞的克隆演化过程。首先通过HepG2细胞优化了单细胞全基因组扩增方法,其次用Fluidigm公司的微流控芯片捕获BCC单细胞进行全基因组扩增,然后通过外显子组测序获得SCUBE3和MST1L基因碱基突变信息。通过单细胞靶向扩增和Sanger测序,成功在BCC单细胞中检测到SCUBE3和MST1L基因碱基突变信息。本研究建立的方法为肿瘤细胞的克隆演化研究提供了一种可靠的技术方案。.
Keywords: clonal evolution; mutation; single-cell; tumor cell.