BACKGROUND Loss of monoubiquitination of histone H2B (H2Bub1) was found to be associated with poor differentiation, cancer stemness, and enhanced malignancy of non-small cell lung cancer (NSCLC). Herein, we investigated the biological significance and therapeutic implications of ubiquitin-specific protease 22 (USP22), an H2Bub1 deubiquitinase, in non-small cell lung cancer (NSCLC). METHODS USP22 expression and its clinical relevance were assessed in NSCLC patients. The effects of USP22 knockout on sensitivity to cisplatin and irradiation, and growth, metastasis of NSCLC xenografts, and survival of cancer-bearing mice were investigated. The underlying mechanisms of targeting USP22 were explored. RESULTS Overexpression of USP22 was observed in 49.0% (99/202) of NSCLC tissues; higher USP22 immunostaining was found to be associated with enhanced angiogenesis and recurrence of NSCLC. Notably, USP22 knockout dramatically suppressed in vitro proliferation, colony formation; and angiogenesis, growth, metastasis of A549 and H1299 in mouse xenograft model, and significantly prolonged survival of metastatic cancer-bearing mice. Furthermore, USP22 knockout significantly impaired non-homologous DNA damage repair capacity, enhanced cisplatin and irradiation-induced apoptosis in these cells. In terms of underlying mechanisms, RNA sequencing and gene ontology enrichment analysis demonstrated that USP22 knockout significantly suppressed angiogenesis, proliferation, EMT, RAS, c-Myc pathways, concurrently enhanced oxidative phosphorylation and tight junction pathways in A549 and H1299 NSCLC cells. Immunoblot analysis confirmed that USP22 knockout upregulated E-cadherin, p16; reduced ALDH1A3, Cyclin E1, c-Myc, and attenuated activation of AKT and ERK pathways in these cells. CONCLUSIONS Our findings suggest USP22 plays critical roles in the malignancy and progression of NSCLC and provide rationales for targeting USP22, which induces broad anti-cancer activities, as a novel therapeutic strategy for NSCLC patient.

中文翻译：

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泛素特异性蛋白酶 22 对非小细胞肺癌的体内血管生成、生长和转移至关重要。

背景研究发现组蛋白 H2B (H2Bub1) 单泛素化缺失与非小细胞肺癌 (NSCLC) 的分化差、癌症干性和恶性程度增强有关。在此，我们研究了泛素特异性蛋白酶 22 (USP22)（一种 H2Bub1 去泛素化酶）在非小细胞肺癌 (NSCLC) 中的生物学意义和治疗意义。方法 在 NSCLC 患者中评估 USP22 表达及其临床相关性。研究了 USP22 敲除对顺铂和放疗的敏感性以及 NSCLC 异种移植物的生长、转移和荷癌小鼠存活率的影响。探讨了靶向 USP22 的潜在机制。结果 在 49.0% (99/202) 的 NSCLC 组织中观察到 USP22 过表达；发现较高的 USP22 免疫染色与 NSCLC 的血管生成增强和复发有关。值得注意的是，USP22 敲除显着抑制了体外增殖、集落形成；A549 和 H1299 在小鼠异种移植模型中的血管生成、生长、转移，并显着延长了转移性荷癌小鼠的生存期。此外，USP22 敲除显着削弱了这些细胞中的非同源 DNA 损伤修复能力，增强了顺铂和辐射诱导的细胞凋亡。在潜在机制方面，RNA测序和基因本体富集分析表明，USP22敲除显着抑制了A549和H1299 NSCLC细胞的血管生成、增殖、EMT、RAS、c-Myc通路，同时增强了氧化磷酸化和紧密连接通路。免疫印迹分析证实 USP22 敲除上调了 E-cadherin，p16；减少 ALDH1A3、细胞周期蛋白 E1、c-Myc，并减弱这些细胞中 AKT 和 ERK 通路的激活。结论我们的研究结果表明，USP22 在 NSCLC 的恶性和进展中起着关键作用，并为靶向 USP22 作为 NSCLC 患者的新治疗策略提供理论依据，USP22 诱导广泛的抗癌活性。