miR-128a对喉癌干细胞生长能力的影响及相关机制的研究

The research on the influences of miRNA on cancer stem cells has become the current frontier and hot topic. In other tumors, it has been identified that miR-128a targeted BMI1 gene, so as to have effects on cancer stem cells. However, till now there is no reports about the function of miR-128a on laryngeal cancer stem cells and its related mechanisms. Our research group found that miR-128a was significantly lower expressed in CD133+ laryngeal cancer stem cells and we was the first to prove that BMI1 maintained the proliferative capacity of CD133+ laryngeal cancer stem cells and influenced related signal pathways. This project will have further research on the influences of miR-128a on the growth capability of laryngeal cancer stem cells and deeply investigate, in laryngeal cancer stem cells,the target function of miR-128a on BMI-1 gene and the influences on related signal pathways. Besides, it has been confirmed that in other tumors, ROS was able to inhibite the growth of cancer stem cells and miR-128a promoted the increase of ROS in cancer cells. Therefore, in this project, we will also explore the influnces of miR-128a on the intracellular ROS of laryngeal cancer stem cells and related signal pathway, which will lay a solid fundation for further research on the cross talk of signal pathways. This project will further reveal the pathogenesis of laryngeal cancer, promote the improvement of clinical effects and the enhancement of prognosis, which makes radical cure of laryngeal cancer become possible.

miRNA对肿瘤干细胞的作用已经成为目前的前沿热点研究, miR-128a靶向BMI1基因作用于肿瘤干细胞已在其他肿瘤中证实，但是miR-128a对于喉癌干细胞的作用及其相关机制迄今尚未报道。本项目组发现miR-128a在CD133+喉癌干细胞中低表达，同时已率先证实BMI-1能够维持CD133+喉癌干细胞的增殖能力，并对相关信号通路产生影响。本项目将进一步研究miR-128a对喉癌干细胞生长能力的影响，并探讨喉癌干细胞中miR-128a对BMI-1基因的靶向作用以及相关信号通路的影响。此外，最新研究证实活性氧自由基（ROS）抑制肿瘤干细胞生长，miR-128a能够促进肿瘤细胞内ROS增加，因此本项目还将探索miR-128a对喉癌干细胞内ROS及相关信号通路的影响，为研究信号通路间的交叉对话奠定基础。该项目将进一步揭示喉癌发病机制，促进临床疗效的提高和预后的改善，使彻底根治喉癌成为可能。

喉癌是头颈部最常见恶性肿瘤之一，近年来发病率逐年上升，更重要的是其年龄段也呈现出年轻化的趋势。功能性微创手术、放射治疗、化学药物治疗及生物治疗等综合性治疗措施的共同应用，已使患者的5 年生存率及生活质量大大提高。但喉癌的复发、转移，对放疗不敏感及化疗药物耐受等问题，常使晚期喉癌的治疗效果欠佳，同时喉癌的预防与早期诊断也一直是传统方法无力解决的问题，这些迫切需要我们从新的视角来进行解释和研究，从而解决这些问题。针对miRNA的研究是肿瘤学的热点研究方向之一，miRNA 对肿瘤的增殖能力等生物学特性的影响已经在慢性淋巴细胞白血病、肺癌、肝癌、前列腺癌等诸多肿瘤中得以证实。因此，本项目对miRNA-128a对喉癌细胞增殖的作用和机制进行了研究。.我们收集了喉癌实体瘤组织和癌旁组织，发现miR-128a在喉癌肿瘤中的表达量显著低于癌旁组织。从喉癌Hep-2细胞系中分离出CD133+喉癌干细胞，证实了miR-128a在喉癌干细胞中的表达比非干细胞中也是明显降低。将miR-128a过表达后，通过体外细胞增殖实验、成球实验，发现过表达miR-128a能够抑制喉癌Hep2细胞增殖。同时，体外细胞凋亡实验结果表明过表达miR-128a能够促进喉癌Hep2细胞凋亡。NOD/SCID小鼠体内成瘤实验证实过表达miR-128a的喉癌细胞的成瘤能力明显下降。将喉癌Hep-2细胞系和AMC-HN8细胞系中的miR-128a均过表达后，通过化疗实验，发现过表达miR-128a能降低喉癌细胞对顺铂和紫杉醇的抑制性。放疗实验证实miR-128a能够促进喉癌细胞的放疗敏感性。更重要的是，miR-128a过表达细胞中的BMI1表达量显著降低，表明miR-128a可能是通过靶向BMI1来发挥这些作用的。这些研究成果将有助于喉癌分子诊断试剂的研发，以及喉癌特异性化疗药物的研发和改良，对喉癌和预防和提高治疗效果都起到促进作用。