Rationale: Peritoneal metastasis predicts poor prognosis of gastric cancer (GC) patients, and the underlying mechanisms are poorly understood./nMethods: The 2-DIGE, MALDI-TOF/TOF MS and single-cell transcriptome were used to detect differentially expressed proteins among normal gastric mucosa, primary GC and peritoneal metastatic tissues. Lentiviruses carrying shRNA and transcription activator-like effector nuclease technology were used to knock down myosin heavy chain 9 (MYH9) expression in GC cell lines. Immunofluorescence, immune transmission electron microscopy, chromatin fractionation, co-immunoprecipitation, and assays for chromatin immunoprecipitation, dual luciferase reporter, agarose-oligonucleotide pull-down, flow cytometry and cell anoikis were performed to uncover nuclear MYH9-induced β-catenin (CTNNB1) transcription in vitro. Nude mice and conditional transgenic mice were used to investigate the findings in vivo./nResults: We observed that MYH9 was upregulated in metastatic GC tissues and was associated with a poor prognosis of GC patients. Mechanistically, we confirmed that MYH9 was mainly localized in the GC cell nuclei by four potential nuclear localization signals. Nuclear MYH9 bound to the CTNNB1 promoter through its DNA-binding domain, and interacted with myosin light chain 9, β-actin and RNA polymerase II to promote CTNNB1 transcription, which conferred resistance to anoikis in GC cells in vitro and in vivo. Staurosporine reduced nuclear MYH9 S1943 phosphorylation to inhibit CTNNB1 transcription, Wnt/β-catenin signaling activation and GC progression in both orthotropic xenograft GC nude mouse and transgenic GC mouse models./nConclusion: This study identified that nuclear MYH9-induced CTNNB1 expression promotes GC metastasis, which could be inhibited by staurosporine, indicating a novel therapy for GC peritoneal metastasis.

中文翻译：

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星形孢菌素靶向核 MYH9 诱导的 CTNNB1 转录，促进胃癌细胞失巢凋亡抵抗和转移。

理由：腹膜转移预示胃癌（GC）患者预后不良，其潜在机制尚不清楚。/n方法：采用2-DIGE、MALDI-TOF/TOF MS和单细胞转录组检测差异表达蛋白正常胃粘膜、原发性胃癌和腹膜转移组织。携带 shRNA 和转录激活子样效应核酸酶技术的慢病毒被用来敲低 GC 细胞系中肌球蛋白重链 9 (MYH9) 的表达。进行免疫荧光、免疫透射电子显微镜、染色质分级分离、免疫共沉淀以及染色质免疫沉淀、双荧光素酶报告基因、琼脂糖寡核苷酸下拉、流式细胞术和细胞失巢凋亡分析来揭示核 MYH9 诱导的 β-连环蛋白 ( CTNNB1 )体外转录。使用裸鼠和条件转基因小鼠在体内研究结果。/n结果：我们观察到 MYH9 在转移性 GC 组织中表达上调，并且与 GC 患者的不良预后相关。从机制上讲，我们通过四个潜在的核定位信号证实了 MYH9 主要定位于 GC 细胞核中。核MYH9通过其DNA结合域与CTNNB1启动子结合，并与肌球蛋白轻链9、β-肌动蛋白和RNA聚合酶II相互作用，促进CTNNB1转录，从而在体外和体内赋予GC细胞对失巢凋亡的抵抗力。在正交异种移植 GC 裸鼠和转基因 GC 小鼠模型中，星形孢菌素可降低核 MYH9 S1943 磷酸化，从而抑制CTNNB1转录、Wnt/β-catenin 信号激活和 GC 进展。/n 结论：本研究发现核 MYH9 诱导的 CTNNB1 表达可促进 GC星形孢菌素可以抑制转移，这表明它是治疗GC腹膜转移的一种新疗法。