miR-191通过BASP1/WT1调控EMT和肿瘤干细胞特性获得在砷所致肺癌和肝癌中作用

Arsenic is an environmental carcinogen that causes the serious hazard to human health and the carcinogenesis of lung and liver, etc, yet its molecular mechanisms remain unclear. Epithelial-mesenchymal transition (EMT) and the acquisition of cancer stem cell-like properties are involved in tumorigenesis, however, their roles and mechanisms in carcinogenesis induced by environmental carcinogens remain largely investigated. Based on our preliminary results that arsenic induced the malignant transformation, EMT, and the acquisition of cancer stem cell-like properties of human bronchial epithelial (HBE) cells and human liver epithelial (THLE-3) cells, we are going to investigate the roles of brain acid soluble protein 1 (BASP1)/ the Wilms' tumor （WT1）-regulated EMT and cancer stem cell-like properties induced by miR-191 in arsenic-induced carcinogenesis of lung and liver, to evaluate the effect of methylation on them, and to identify miR-191 and BASP1 as emerging molecular markers and therapeutic targets by using the following three models. (i) Cell model, treatememt of HBE cells and THLE-3 cells by arsenic in the presence or absence of S-adenosylmethionine (SAM), methyl donor, anti-miR-191 and miR-191 mimic, or Tet-off system to regulate the level of BASP1, respectively; (ii) The nude mice model of transformed cells-induced tumor; (iii) The CD1 mice model of tumorigenesis induced by arsenic in the presence or absence of hypermethyl food. Our results will be helpful to understand the molecular mechanisms underlying arsenic-induced carcinogenesis of lung and liver, which will provide new clues to find the early biomarkers and the new measures of preventing and treating arseniasis.

砷是一种严重危害人类健康的环境致癌物，其可引起肺癌和肝癌等肿瘤，其分子机制尚不清楚。上皮间质转化（EMT）和肿瘤干细胞特性获得参与了肿瘤发生发展，而其在环境致癌物所致肿瘤中的作用及机制研究报道甚少。本项目在已发现亚砷酸钠诱导肺HBE和肝THLE-3细胞恶性转化过程中产生EMT和肿瘤干细胞特性获得的研究基础上，分别通过亚砷酸钠单独或联合应用甲基供体SAM、正义和反义miR-191、Tet-off系统调控BASP1水平处理肺HBE和肝THLE-3细胞、在裸鼠致瘤模型及砷联合摄入高甲基膳食处理CD1小鼠后，从正向和反向探讨miR-191通过BASP1/WT1调控EMT和肿瘤干细胞特性获得在砷所致肺癌和肝癌中作用及甲基化对其影响、miR-191和BASP1作为砷致癌作用新兴分子标志及治疗靶标的意义，以揭示砷引起肺癌和肝癌的部分分子机制，为寻找砷所致危害的早期生物标志和发现新的防治措施提供新线索。

砷是一种严重危害人类健康的环境毒物，其可以引起肺和肝等组织损害及肿瘤，但砷所致损害和致癌作用的分子机制尚不清楚。本项目利用已建立亚砷酸钠（NaAsO2）慢性处理人支气管上皮（HBE）细胞和肝上皮L-02细胞发生上皮间质转化（EMT）、肿瘤干细胞（CSCs）特性获得及恶性转化细胞模型；不同程度砷暴露人群血清；饮用不同浓度亚砷酸钠饮水所致亚慢性砷中毒及采用“经胎盘染毒+终生染毒”方式构建亚砷酸钠诱导肺和肝组织损害和肿瘤的小鼠动物模型后。运用多种分子生物学和毒理学方法开展系列研究，结果发现：①miR-191通过BASP1/WT1介导EMT和CSCs特性获得在亚砷酸钠所致肺和肝细胞恶性转化过程中具有重要作用；②HIF-2α介导的炎症反应和miR-191参与亚砷酸钠所致肺细胞血管生成及侵袭转移能力增强；③炎症调控的miR-21通过靶基因PDCD4而激活Twist1参与亚砷酸钠所致肺细胞EMT及侵袭转移；④miR-21通过靶基因PTEN激活ERK参与亚砷酸钠所致肝细胞自噬过程；⑤MALAT1与HIF-2α反馈调控在亚砷酸钠所致肝细胞EMT和CSCs特性获得及恶性转化中具有重要作用；⑥砷暴露人群血清乳酸和IL-6/8及长链非编码RNAs水平与暴露水平呈正相关；⑦亚砷酸钠亚慢性处理和生命早期（亲代和宫内）暴露及终生染毒可引起肺和肝组织炎症反应和严重损害及肿瘤发生率升高，其可能与HIFs和IL-6水平升高有关。获得的研究结果揭示了砷暴露所致肺和肝组织损害及肿瘤发生发展的部分分子机制，并为寻找砷中毒的早期生物标志和发现新的防治措施提供新线索。本项目已发表论文10篇（均标注该项目），其中SCI论文8篇，获得后续国家自然科学基金1项，培养博士/硕士研究生12名及青年教师2名。本项目的研究结果不仅对于地方性砷中毒而且对于环境砷暴露所致机体损害的防控具有重要科学意义和一定应用价值。