Zhai Shicong, Liu Cui, Zhang Lichen, Zhu Jian, Guo Jiqiang, Zhang Jinghang, Chen Zhijun, Zhou Wenping, Chang Tingmin, Xu Siguang, Qi Yijun, Zhuang Ting, Yu Na, Wang Weilong, Wang Hui, Yu Sifan, Li Xiumin
Center for Cancer Research, Xinxiang Medical University, Xinxiang, Henan, China; Department of Gastroenterology, the Third Affiliated Hospital of Xinxiang Medical University, Xinxiang, Henan, China.
School of Nursing, Xinxiang Medical University, Henan, China.
Neoplasia. 2017 Mar;19(3):154-164. doi: 10.1016/j.neo.2016.12.007. Epub 2017 Jan 29.
Esophageal cancer is among the most deadly malignant diseases. However, the genetic factors contributing to its occurrence are poorly understood. Multiple studies with large clinic-based cohorts revealed that variations of the phospholipase C epsilon (PLCE1) gene were associated with esophageal cancer susceptibility. However, the causative role of PLCE1 in esophageal cancer is not clear. We inactivated the functional alleles of PLCE1 by CRISPR/Cas9 genome editing technology. The resultant PLCE1 inactivated cells were analyzed both in vitro and in vivo. Our results showed that loss of PLCE1 dramatically decreased the invasion and proliferation capacity of esophageal carcinoma cells in vitro. Moreover, such PLCE1 inactivated tumor grafts exhibited significantly decreased tumor size in mice. We found that PLCE1 was required to maintain protein level of snail a key transcription factor responsible for invasion. Our further transcriptomic data revealed that deficient cells were significantly decreased in expression of genes enriched as targets of Snail. Strikingly, recovery of Snail protein at least partially rescued the invasion and proliferation capacity in PLCE1 inactivated cells. In ESCC clinical specimens, PLCE1 was correlated with tumor stage (P<.0001). Interestingly, PLCE1 expression was positively correlated Snail by immunohistochemistry in such specimens (P<.0001). Therefore, our functional experiments showed the essential roles of PLCE1 in esophageal carcinoma cells and provided evidences that targeting PLCE1 and its downstream molecules could be effective therapies for esophageal cancer.
食管癌是最致命的恶性疾病之一。然而，导致其发生的遗传因素却知之甚少。多项基于大型临床队列的研究表明，磷脂酶Cε（PLCE1）基因的变异与食管癌易感性相关。然而，PLCE1在食管癌中的致病作用尚不清楚。我们通过CRISPR/Cas9基因组编辑技术使PLCE1的功能等位基因失活。对由此产生的PLCE1失活细胞进行了体外和体内分析。我们的结果表明，PLCE1的缺失显著降低了食管癌细胞在体外的侵袭和增殖能力。此外，这种PLCE1失活的肿瘤移植物在小鼠体内的肿瘤大小显著减小。我们发现，维持蜗牛蛋白（一种负责侵袭的关键转录因子）的蛋白水平需要PLCE1。我们进一步的转录组数据显示，缺陷细胞中作为蜗牛靶标的基因表达显著降低。引人注目的是，蜗牛蛋白的恢复至少部分挽救了PLCE1失活细胞的侵袭和增殖能力。在食管癌临床标本中，PLCE1与肿瘤分期相关（P<0.0001）。有趣的是，在此类标本中，通过免疫组织化学检测，PLCE1表达与蜗牛蛋白呈正相关（P<0.0001）。因此，我们的功能实验表明了PLCE1在食管癌细胞中的重要作用，并提供了证据表明靶向PLCE1及其下游分子可能是治疗食管癌的有效方法。
