Acta Biochim Biophys Sin (Shanghai). 2022 Feb 25;54(2):179-186. doi: 10.3724/abbs.2021027.
Hypoxia-induced epigenetic regulation calls for more effective therapeutic targets for esophageal cancer. We used GEPIA and UALCAN databases to screen survival-related and cancer stage-associated genes. Eca109 and KYSE450 esophageal cancer cell lines were cultured under normoxia, hypoxia, or CoCl-induced hypoxia conditions, which were further transfected with plasmids expressing RB binding protein 7 (RBBP7), hypoxia-inducible factor 1 (HIF1)-α, or RBBP7 shRNA. Colony formation and MTT assays were used to detect cell proliferation. Tumor sphere formation and stemness marker detection were applied to assess cell stemness. RT-PCR and western blot analysis were used to detect the relative mRNA level and protein expression, respectively. Luciferase assay was utilized to detect the direct interaction between HIF1α and RBBP7. Up-regulated RBBP7 was identified as one of the most prominent survival-related genes, which is negatively correlated with the overall survival (OS), disease recurrence-free survival (DFS), and tumor stages. Hypoxia-induced HIF1α up-regulates RBBP7 expression, which promotes esophagus cancer cell viability, proliferation, and stemness with increased cyclin-dependent kinase 4 (CDK4) expression. Luciferase reporter assay verified that HIF1α transcriptionally regulates the expression of RBBP7. We conclude that hypoxia induces high expression of RBBP7 which is at least partially mediated by HIF1α, up-regulates the expression of downstream CDK4, and thereby promotes tumor progression in esophageal cancer cells.
缺氧诱导的表观遗传调控呼吁寻找更有效的食管癌治疗靶点。我们使用 GEPIA 和 UALCAN 数据库筛选与生存相关和癌症分期相关的基因。在常氧、缺氧或 CoCl 诱导的缺氧条件下培养 Eca109 和 KYSE450 食管癌细胞系，并进一步用表达 RB 结合蛋白 7（RBBP7）、缺氧诱导因子 1（HIF1）-α或 RBBP7 shRNA 的质粒转染。通过集落形成和 MTT 分析检测细胞增殖。通过肿瘤球形成和干细胞标志物检测评估细胞干性。通过 RT-PCR 和 Western blot 分析分别检测相对 mRNA 水平和蛋白表达。利用荧光素酶测定检测 HIF1α 和 RBBP7 之间的直接相互作用。上调的 RBBP7 被鉴定为最显著的生存相关基因之一，与总生存（OS）、疾病无复发生存（DFS）和肿瘤分期呈负相关。缺氧诱导的 HIF1α 上调 RBBP7 的表达，从而促进食管癌细胞活力、增殖和干性，增加周期蛋白依赖性激酶 4（CDK4）的表达。荧光素酶报告测定验证了 HIF1α 转录调节 RBBP7 的表达。我们得出结论，缺氧诱导 RBBP7 的高表达，至少部分是由 HIF1α 介导的，上调下游 CDK4 的表达，从而促进食管癌细胞的肿瘤进展。
