雄激素经AR/PI3K/AKT通路调控CA916798参与肺腺癌发生的作用及机制研究

CA916798 is a new cisplatin resistance related gene of lung cancer which was first discoverd,reported and validated by our preceding work and the research supported by National Natural Science Fund No.30470773,but its role in lung tumorigenesis and associated regulation machanism still remains largely unknown. Our previous work has confirmed that the gene was highly expressed in lung cancer, while low expressed in paracancerous tissues of lung cancer, normal lung epithelial cells , and it also has an anti-apoptotic function. According to all these discoveries, we speculate that CA916798 may be a new lung adenocarcinoma-associated gene. Our objects in this study are: establishing cell lines with CA916798 knockout or over-expressed, basing on lung adenocarcinoma A549 cells(with a high level expression of CA916798 and AR) and lung epithelial cells 16HBE(with a low level expression of CA916798 and AR), related nude mouse xenograft model as well;testing cell proliferation, cell cycle, cell transformation and tumorigenicity , PI3K/AKT pathway, c-myc、AR、SP1、expression of apoptosis-related gene and protein as well as the impact on animal growth and development in condition of CA916798 is knockout or over-expressed; detect its promoter and to investigate the regulatory mechanism ,in order to provide theoretical basis for further study of the function of this gene and clinical targeted therapy.

CA916798基因是我们在前期研究和No.30470773资助下首先发现、报告并证实的与肺癌顺铂耐药相关的新基因，但其在肺腺癌发生中的作用及其调控机制仍不清楚。前期我们已证实该基因在肺癌中高表达而在肺癌旁组织、肺正常上皮细胞中低表达，并有抗凋亡作用；雄激素刺激可导致CA916798基因表达明显增高，据此推测该基因可能是新的肺腺癌相关基因。本课题拟以高表达该基因和AR的肺腺癌细胞A549和低表达该基因和AR的肺上皮细胞16HBE为研究对象，建立基因敲除和持续高表达细胞系及相关裸鼠移植瘤模型，在敲除CA916798及抑制AR或持续高表达CA916798及AR的条件下，检测细胞增殖、细胞周期、细胞转化、成瘤能力、PI3K/AKT通路、c-myc、AR、SP1、凋亡相关基因及蛋白表达的变化；另外，检测其启动子，探讨其调控机制，为进一步明确该基因的功能并为临床靶向治疗奠定理论基础。

CA916798基因是我们在前期研究和No.30470773资助下首先发现、报告并证实的与肺癌顺铂耐药相关的新基因，我们已证实该基因在肺癌中高表达，受到PI3K/AKT通路的调控，并有抗凋亡作用。有文献报道，雄激素刺激可导致前列腺LNCap细胞CA916798基因表达明显增高。通过查询数据库,发现该基因有10个转录本，均编码同一个蛋白质,在多种肿瘤细胞和组织中高表达,同时该基因的表达水平与部分肿瘤的预后呈负相关，但我们对该基因的具体结构、功能、调控机制，以及在不同肿瘤中的作用等了解仍很少。我们构建了A549细胞的CA916798基因敲除的细胞模型，构建了CA916798基因和AR基因的过表达或敲低的慢病毒载体。研究了CA916798基因对肺腺癌A549细胞和前列腺癌LNCap细胞功能的影响，发现CA916798基因可促进两种细胞的增殖、迁移和侵袭。在前列腺癌LNCap细胞中，双氢睾酮刺激后CA916798基因明显升高，CHIP和双荧光素酶实验显示AR可以作为转录因子结合到CA916798基因的启动子区。但在肺腺癌A549细胞中，双氢睾酮刺激后CA916798基因无明确的升高趋势。我们研究还发现SHP2可以通过PI3K/AKT通路调控CA916798基因，从而参与小细胞肺癌的化疗耐药。根据这些研究结果，我们认为CA916798基因受到了不同信号通路或分子，包括PI3K/AKT、SHP2、雄激素-雄激素受体等的调控，在多种肿瘤中包括肺腺癌、小细胞肺癌、前列腺癌中均有作用。继续深入研究该基因的功能和调控机制，能够为肺癌和其他肿瘤的治疗提供新的候选靶点。