OTUB2对EIF4A3的去泛素化和稳定有助于TPI1介导的糖酵解和TNBC进展

摘要(中文译文)

背景：肿瘤细胞依赖增强的糖酵解能力来促进细胞生长和进展。然而，调控三阴性乳腺癌（TNBC）糖酵解的分子机制在很大程度上仍不清楚。在本研究中，我们阐明了OTUB2在调控TNBC糖酵解中的作用，并深入探讨其机制。方法：我们利用癌症基因组图谱（TCGA）数据集分析OTUB2、EIF4A3和TPI1在乳腺癌组织及三阴性乳腺癌（TNBC）组织中的表达。采用qPCR和western blot实验证实OTUB2、EIF4A3和TPI1在TNBC组织和细胞系中的蛋白表达。随后，进行过表达和敲低实验以及细胞功能实验，以阐明OTUB2对EIF4A3/TPI1介导的TNBC恶性进展的影响及相关分子机制。最后，建立异种移植小鼠模型以验证OTUB2在体内的作用。结果：TCGA数据库显示OTUB2、EIF4A3和TPI1在乳腺癌组织和TNBC组织中高表达。与此一致，与癌旁组织和MCF10A细胞相比，TNBC组织和细胞系中OTUB2、EIF4A3和TPI1的mRNA和蛋白表达均升高。敲低OTUB2可抑制细胞增殖、迁移和侵袭，并降低葡萄糖摄取、ATP水平、乳酸生成和ECAR，而过表达OTUB2则呈现相反趋势。进一步的数据表明，OTUB2通过去泛素化稳定EIF4A3蛋白，且EIF4A3与TPI1相互作用以稳定其mRNA。过表达EIF4A3加剧了TNBC恶性活动及糖酵解，而沉默TPI1可逆转这些效应。在体内，敲低OTUB2可显著抑制异种移植小鼠模型中的肿瘤生长。结论：我们得出结论，OTUB2通过去泛素化并稳定EIF4A3，经TPI1介导的肿瘤细胞糖酵解促进TNBC进展。

Abstract

BACKGROUND: Tumor cells rely on enhanced glycolytic capacity to facilitate cell growth and progression. However, the molecular mechanisms governing glycolysis in triple-negative breast cancer (TNBC) remain largely elusive. In this study, we elucidate the role of OTUB2 in regulating glycolysis in TNBC and delve into the mechanisms. METHODS: We utilized The Cancer Genome Atlas (TCGA) dataset to analyze the expressions of OTUB2, EIF4A3, and TPI1 in breast cancer tissues and specifically in triple-negative breast cancer (TNBC) tissues. qPCR and western blot experiments were performed to confirm the protein expressions of OTUB2, EIF4A3, and TPI1 in TNBC tissues and cell lines. Subsequently, overexpression and knockdown experiments followed by cell functional assays were conducted to elucidate the impact of OTUB2 on EIF4A3/TPI1-mediated TNBC malignant progression and related molecular mechanisms. Finally, a xenograft mouse model was established to verify the effect of OTUB2 in vivo. RESULTS: TCGA database indicated highly expressions of OTUB2, EIF4A3, and TPI1 in breast cancer tissues and TNBC tissues. Consistently, the mRNA and protein expressions of OTUB2, EIF4A3, and TPI1 were increased in TNBC tissues and cell lines, as compared to para-carcinoma tissues and MCF10A cells. OTUB2 knockdown inhibited cell proliferation, migration and invasion, and decreased glucose uptake, ATP level, lactate production, and ECAR, while the OTUB2 overexpression exhibited the opposite trends. Further data elucidated that OTUB2 stabilized the EIF4A3 protein via deubiquitination, and EIF4A3 interacted with TPI1 to stabilize its mRNA. Overexpression of EIF4A3 exacerbated TNBC malignant activities and glycolysis, while silencing TPI1 reversed these effects. In vivo, the knockdown of OTUB2 significantly inhibited tumor growth in a xenograft mouse model. CONCLUSIONS: We conclude that OTUB2 deubiquitinates and stabilizes EIF4A3 to promote TNBC progression via TPI1-mediated glycolysis of tumor cells.

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