DNA-PKcs通过增强肿瘤干性介导局部晚期喉癌放疗抵抗的机制研究

Radioresistance severely affects the overall efficacy of locally advanced laryngeal cancer, which is related to the cancer stem cell and cell repair, but the specific mechanism is unclear. DNA-PKcs is the DNA damage repair enzymes, which proved to be involved in the repair of radiation damage. Our preliminary experimental results showed that DNA-PKcs was highly expressed in laryngeal cancer tissue, and CD133+ laryngeal cancer cells were significantly increased in laryngeal cancer tissues which resistant to radiotherapy. The expression of DNA-PKcs in CD133+ laryngeal cancer stem cell was significantly increased after radiotherapy, while knockdown of DNA-PKcs could reduce the ability of proliferation, invasion and spheroidization rate. These results suggested that DNA-PKcs participated in radioresistance by regulating the cancer stem cell properties, he results were also verified by in vivo experiments. In addition, the mechanism study revealed that DNA-PKcs had bound to the promoter of β-catenin, to activate β-catenin-dependent transcription and subsequently cancer stem cell-like properties. .These results suggest that DNA-PKcs-Wnt/β-catenin signaling pathway is involved in radioresistance of laryngeal cancer by regulating cancer stem cell-like properties and cell damage repair. This project is going to verify the binding site, analyze and validate the above scientific hypotheses through in vivo, vitro functional experiments and mechanism explorations. In order to provide a new strategy to overcome the radioresistance of locally advanced laryngeal cancer.

放疗抵抗严重影响局部晚期喉癌整体疗效，其与肿瘤细胞干性增强和修复相关，但具体机制不明。DNA-PKcs是DNA损伤修复酶，它与干细胞被证明参与放疗的损伤修复，我们预实验研究结果显示：DNA-PKcs在喉癌中高表达，放疗抵抗喉癌组织中CD133+喉癌细胞明显增多。CD133+放疗抵抗喉癌干细胞中DNA-PKcs表达显著升高；而敲低DNA-PKcs后则可降低放疗抵抗细胞的增殖、侵袭以及成球能力。提示DNA-PKcs通过调控喉癌干细胞特性参与放疗抵抗，并在体内实验得到验证。此外机制研究显示：DNA-PKcs通过与β-catenin启动子区域结合，促进其转录和表达，并与干性相关。以上结果提示DNA-PKcs-Wnt/β-catenin通路通过调控干性参与喉癌放疗抵抗。本项目拟通过体内、体外功能实验及机制研究，明确其结合域，深入分析并验证上述科学假设。以期为克服局部晚期喉癌放疗抵抗提供新策略。

放疗抵抗严重影响局部晚期喉癌整体疗效，其与肿瘤细胞干性增强和修复相关，但具体机制不明。DNA-PKcs是DNA损伤修复酶，它与干细胞被证明参与放疗的损伤修复，我们预实验研究结果显示：DNA-PKcs在喉癌中高表达，放疗抵抗喉癌组织中CD133+喉癌细胞明显增多。CD133+放疗抵抗喉癌干细胞中DNA-PKcs表达显著升高；而敲低DNA-PKcs后则可降低放疗抵抗细胞的增殖、侵袭以及成球能力。提示DNA-PKcs通过调控喉癌干细胞特性参与放疗抵抗，并在体内实验得到验证。此外机制研究显示：DNA-PKcs通过与β-catenin启动子区域结合，促进其转录和表达，并与干性相关。以上结果提示DNA-PKcs-Wnt/β-catenin通路通过调控干性参与喉癌放疗抵抗。本项目通过上调/沉默喉癌细胞株DNA-PKcs表达水平，在细胞水平验证DNA-PKcs表达对肿瘤细胞迁移、侵袭、干性及放疗敏感性的作用。分子水平探索DNA-PKcs与β-catenin启动子区域的结合域及其靶向调控的下游信号通路。临床水平收集局部晚期喉癌组织、病理标本和临床资料，检测DNA-PKcs的表达水平。目前结果发现DNA-PKcs表达增高促进肿瘤细胞的迁移、侵袭及干性，降低放疗敏感性。DNA-PKcs与β-catenin启动子区域的结合域及其靶向调控的下游信号通路探索中。临床标本正在收集中。