SHIP2靶向调控AKT对喉鳞癌放射敏感性的影响及机制研究

Laryngeal cancer is one of the malignant tumor which is not sensitive to radiation, radiation resistance is the important cause of the failure of tumor local recurrence or radiation therapy, the key to increase the radiosensitivity of laryngeal cancer cells, especially the radioresistant ones is to seek feasible predictor. Previous we screening and first known SHIP2 high expression in laryngeal squamous radiation resist plant through the establishment of laryngeal cancer radiation resistance strain model by proteomic analysis. We hypothesized that SHIP2 associated with radioresistant of laryngeal cancer. This topic plans to build the high expression of SHIP2 and ShRNA slow virus expression vector transfected different radiosensitivity of laryngeal squamous cell lines, using in vivo and in vitro experiment to test its radiation sensitivity and cell biology behavior change, and further detect modification of expression of SHIP2 on Akt phosphorylation level and downstream target genes in laryngeal cancer cells. To learn more about laryngeal cancer molecular mechanism of radiation resistance, offers a new molecular markers and therapeutic targets for radiotherapy.

喉癌是对放射线不敏感的恶性肿瘤之一，其中放射抗拒是导致其局部复发或放疗失败的重要原因,寻求放射敏感性的可行预测指标，是增加喉癌细胞特别是辐射耐受细胞放射敏感性的关键。前期我们通过建立喉鳞癌放射抗拒株模型，通过蛋白组学技术筛选并首次发现SHIP2在喉鳞癌放射抗拒株中高表达。据此我们推测SHIP2和喉癌放疗抵抗相关。本课题拟构建SHIP2的高表达及ShRNA的慢病毒表达载体，分别转染不同放射敏感性的喉鳞癌细胞株，采用体内外试验检测其放射敏感性及生物学行为改变，分析SHIP2表达对喉癌细胞Akt磷酸化水平及下游靶基因的影响，进一步了解喉癌对放疗抵抗的内在分子机制,为放射治疗提供新的分子标记和治疗靶点。

喉癌是对放射线不敏感的恶性肿瘤之一，其中放射抗拒是导致其局部复发或放疗失败的重要原因,寻求放射敏感性的可行预测指标，是增加喉癌细胞特别是辐射耐受细胞放射敏感性的关键。前期我们通过建立喉鳞癌放射抗拒株模型，通过蛋白组学技术筛选并首次发现 SHIP2在喉鳞癌放射抗拒株中高表达。据此我们推测SHIP2和喉癌放疗抵抗相关。研究发现，PI3K/Akt信号通路在多种肿瘤（包括喉癌）中激活，活化的Akt通过PI3K/Akt信号转导通路介导细胞生长、凋亡、细胞周期调节，促进侵袭转移和血管生成，且SHIP2在恶性肿瘤中发挥重要调控作用与PI3K/Akt信号通路的活化相关，而PI3K/Akt通路活化与肿瘤的放射抵抗密切相关。虽已有研究发现在喉鳞状细胞癌组织中SHIP2高表达与其不良预后相关，但并未有相关报道探究在喉癌中SHIP2表达与放射敏感性的关联。因此，本课题旨在细胞水平上应用RNA干扰技术，初步探究在喉鳞癌Hep-2细胞中SHIP2表达对其生物学行为的影响以及对放疗增敏的可能机制。.本课题通过siRNA抑制喉鳞癌Hep-2R细胞中SHIP2表达可抑制细胞增殖和侵袭迁移能力，促进细胞凋亡；放射线可抑制喉癌Hep-2R细胞增殖，促进凋亡和细胞周期G2期阻滞，这可能与射线引起的喉癌Hep-2R细胞中SHIP2的表达降低相关；靶向抑制SHIP2可与放射治疗协同抑制喉鳞癌Hep-2R细胞的增殖，促进凋亡和细胞周期G2期阻滞，从而发挥放射增敏的作用。其可能机制：靶向抑制喉癌Hep-2R细胞中SHIP2表达联合放射治疗可通过显著下调PI3K/Akt信号通路活性，进而解除对下游促凋亡因子caspase3和周期阻滞因子p21和p27的抑制作用，从而促进细胞凋亡和细胞周期G2期阻滞而协同增强喉癌Hep-2R细胞的放射敏感性。