CagA+ H.pylori促进lncRNA RCAN1表达在胃癌细胞侵袭转移中的作用及其分子机制研究

Hp infection is closely related with metastasis of gastric cancer, but the mechanism is not clear. Our previous experiment found that expression of lncRNA RCAN1 is high in CagA+Hp infected gastric cancer cells through the lncRNA chip, which is closely related to the metastasis of gastric cancer; FISH indicated that lncRNA RCAN1 and RUNX1 pre-mRNA, its parent gene, are colocalized, interference of lncRNA RCAN1 can reduce the stability of RUNX1 pre-mRNA; Bioinformatics analysis, RIP and qRT-PCR also show that lncRNA RCAN1 can bind with PTBP1 protein, and promote the stability of RUNX1 pre-mRNA jointly. According to the literature and previous experiment, we put forward the hypothesis: " lncRNA RCAN1 is closely related to CagA+Hp infection, it can combine with PTBP1 to enhance stability of RUNX1 pre-mRNA, promote the expression of RUNX1, accelerate metastasis of gastric cancer". This hypothesis will be confirmed by RNA pull-down, Co-IP, mass spectrometry analysis,molecular biology, cell biology experiment in the further study. The confirmation of this hypothesis will provide a new theoretical basis and target for the eradication of Hp after surgery of gastric cancer.

Hp感染与胃癌侵袭转移密切相关,但机制尚不明确.我们前期通过lncRNA芯片筛选发现lncRNA RCAN1在CagA+Hp感染的胃癌细胞中高表达,与胃癌转移密切相关;FISH提示lncRNA RCAN1与其亲本基因RUNX1 pre-mRNA存在共定位,干扰lncRNA RCAN1可以降低RUNX1 pre-mRNA稳定性;通过生物信息学预测,RIP,qRT-PCR实验还发现lncRNA RCAN1可以与PTBP1蛋白结合,共同促进RUNX1 pre-mRNA的稳定性.根据文献和前期实验,我们提出"lncRNA RCAN1与CagA+Hp感染密切相关,通过结合PTBP1增强RUNX1 pre-mRNA稳定性,促进RUNX1表达,介导胃癌转移"的假说,并拟通过RNA pull-down,Co-IP,质谱分析,分子生物学,细胞生物学等加以证实,为胃癌术后根除Hp提供新的理论依据和作用靶点.

幽门螺杆菌（Helicobacter pylori，Hp）感染是已知最强的胃癌危险因素。在Hp感染期间，宿主细胞异常的表观遗传调控和表观遗传修饰可能是Hp感染诱导胃癌进展的重要原因，但机制尚不明确。课题组一方面通过lncRNA 芯片和细胞生物学实验阐明lncRNA TTC30B-1在CagA+Hp感染胃癌细胞中表达显著增高，且与胃癌患者不良预后密切相关；干扰和回复实验证实CagA+Hp上调lncRNA TTC30B-1促进细胞粘附信号通路是诱导胃癌细胞侵袭转移的关键机制。另一方面我们研究证实CagA+Hp感染显著降低胃癌细胞m6A水平，增强m6A去甲基化酶FTO的表达水平，进一步通过MeRIP-seq、MeRIP-PCR、RNA-seq等实验证实FTO以去甲基化酶依赖的方式诱导EMT相关基因表达，促进胃癌细胞发生EMT。因此，我们的研究揭示了CagA+Hp感染诱导胃癌细胞表观遗传调控异常，进而促进胃癌转移的分子机制，将为阻断及治疗Hp感染后胃癌进展提供新的靶点。