骨髓锌指1的表观调控在胃癌化疗敏感性中与金属硫蛋白2A相互作用机制

Gastric cancer (GC) is one of the most common cancers worldwide, currently ranking second in cancer-related mortality. Chemotherapy in addition to surgical removal is an important therapeutic modality for GC. Although considerable effort has been directed towards the improvement of chemotherapeutic intervention, the 5-year survival rate of GC patients remains poor partly due to the development of chemoresistance, raising an urgent need to seek more effective treatment. .Metallothionein 2A (MT2A) and NF-κB are involved in the carcinogenesis and cancer chemosensitivity. However, the primary role of MT2A in relation to NF-κB activation in tumorigenesis and chemoresistance differs depending on cell types and remains unclear in GC. We previously showed a decreased expression of MT2A and IκB-α in human GC in association with poor prognosis of patients. Our recent studies provide the first evidence for epigenetic upregulation of MT2A in GC by diallyl trisulfide (DATS), a garlic-derived compound, and uncover the molecular mechanisms of the anti-GC activity of DATS as well as its ability to sensitize GC cells to the chemotherapeutic reagent docetaxel (DOC) through an "MT2A-NF-κB pathway". However, the precise link between MT2A and NF-κB remains elusive. .We recently found that, myeloid zinc-finger 1 (MZF1), a member of the Kruppel family of zinc-finger proteins, which suppresses the cell proliferation and invasion, is epigenetic silenced in human GC cell lines and primary tumors. We also found an association of MZF1 with MT2A in GC cells. We therefore speculate that MZF1, as a tumor suppressor, may play a critical role in the MT2A-NF-κB pathway to enhance chemosensitivity of human GC cells. .In this study, we plan to systematically investigate the expression and epigenetic regulation of MZF1 in human GC cells and primary tumor tissues. We then will access the functional of MZF1 in GC tumorigenesis in relation to MT2A. In addition, we will explore the capacity of MZF1 to act as a key molecule in MT2A-NF-κB pathway to enhance the chemosensitivity of DATS to human GC cells in vitro and in vivo by generating MZF1 knock-out GC cell model using CRISPR/Cas9 technology. Furthermore, we will examine MT2A/MZF1 expression and epigenetic regulation in GC tumor tissues collected from patients before and after DOC treatment. .Our study will thus delineate a mechanistic basis of MT2A/MZF1-NF-κB signaling in GC, in which MZF1 may be a chemosensitivity predictor for GC patients’ progression and a target for more effective treatment by combination of DATS and DOC.

耐药是胃癌患者化疗常见现象，鉴别药物敏感与耐药的生物标志物具有重要的临床意义。金属硫蛋白2A（MT2A）和NF-κB均被认为是药物敏感相关分子。我们前期研究提出“MT2A-NF-κB”通路是大蒜素衍生物DATS联合化疗药多西他赛发挥抑癌增敏作用的重要途径；并发现骨髓锌指1(Myeloid Zinc-Finger 1, MZF1)在人胃癌组织细胞中呈现表观沉默，过表达或敲降实验结果显示，MZF1具有抑制胃癌细胞增殖与迁移的能力，且与MT2A相互作用调控NF-κB上游关键分子IκB-α的转录。我们推测MZF1在胃癌中发挥抑癌基因样作用，可能是DATS与化疗药发挥抑癌增敏效应的MT2A-NF-κB通路中一关键分子。本项目拟在胃癌组织细胞中系统分析MZF1表达与表观调控的基础上，重点探讨MZF1在增强胃癌化疗敏感性的MT2A-NF-κB通路中的分子作用机制。

我们前期的研究发现MT2A通过使NF-kB通路失活抑制胃癌细胞的增殖，促进肿瘤细胞对化疗药物的敏感性，但是MT2A调控NF-kB通路的机制并不明确。本研究发现MZF1在肿瘤细胞中低表达，具有抑制肿瘤细胞增殖和迁移的功能。机制研究发现MT2A可以和MZF1相互作用形成复合物，通过MZF1和NFKBIA的直接相互作用，调控NFKBIA的转录活性，从而抑制NF-kB通路的激活。重要的是，通过大样本验证，我们发现MZF1的表达受到表观遗传学调控，且该基因联合MT2A可作为胃癌患者的预后标志物。