甲基转移酶样蛋白7B调控USP28/HIF-1α通路促进甲状腺乳头状癌细胞糖酵解及恶性进展OA
Methyltransferase-like protein 7B promotes glycolysis and malignant progression in papillary thyroid carcinoma cells via the USP28/HIF-1α axis
目的:探讨甲基转移酶样蛋白7B(METTL7B)在甲状腺乳头状癌(PTC)中的表达及其在肿瘤代谢重编程及恶性进展中的作用和分子机制.方法:基于基因表达综合数据库(GEO)和癌症基因组图谱(TCGA)分析METTL7B在PTC组织中的表达水平及其与临床特征的关系.采用免疫组织化学染色验证METTL7B在临床组织芯片样本中的表达差异;构建METTL7B稳定敲减细胞株,并通过定量逆转录聚合酶链反应(qRT-PCR)和蛋白质印迹法检测敲减效率.进一步采用MTT法检测细胞增殖能力,克隆形成实验评估克隆形成能力.通过转录组测序分析METTL7B过表达后的差异基因并进行通路富集分析,结合蛋白质印迹法和qRT-PCR验证其对低氧诱导因子1α(HIF-1α)的调控作用.采用放线菌酮处理和泛素化检测评估METTL7B对HIF-1α蛋白稳定性的影响,并进一步探讨泛素特异性蛋白酶28(USP28)在其中的作用.乳酸生成及葡萄糖吸收实验分析METTL7B及HIF-1α对PTC糖酵解的调控.结果:METTL7B在PTC组织中高表达(P<0.05),并与淋巴结转移呈正相关(P<0.05).敲减METTL7B显著抑制PTC细胞增殖及克隆形成能力(均P<0.05),并可显著减缓PTC异种移植瘤的生长速度,其肿瘤体积小于对照组(P<0.05).METTL7B与HIF-1α信号通路密切相关,敲减METTL7B可降低HIF-1α蛋白水平但不影响其mRNA水平.METTL7B可抑制HIF-1α泛素化降解并维持其蛋白稳定性,而去泛素化酶USP28可介导该过程.METTL7B调控USP28/HIF-1α通路上调糖酵解关键基因表达,增强细胞糖酵解活性并促进其恶性生物学行为.结论:METTL7B通过USP28介导的去泛素化作用稳定HIF-1α,从而促进PTC细胞糖酵解和恶性进展.
Objective:To investigate the expression of methyltransferase-like protein 7B(METTL7B)in papillary thyroid carcinoma(PTC)and elucidate its role and molecular mechanisms in tumor metabolic reprogramming and malignant progression.Methods:Public datasets from Gene Expression Omnibus(GEO)and The Cancer Genome Atlas(TCGA)were used to analyze METTL7B expression in PTC and its association with clinicopathological features.Immunohistochemistry on tissue microarrays was performed to validate METTL7B protein expression in clinical samples.Stable METTL7B-knockdown PTC cell lines were constructed,and knockdown efficiency was confirmed by quantitative real-time PCR(qRT-PCR)and Western blotting.Cell proliferation and clonogenic potential were evaluated using MTT and colony formation assays.Transcrip-tome sequencing was conducted in METTL7B-overexpressing cells to identify differentially expressed genes and enriched pathways,followed by qRT-PCR and Western blotting validation of METTL7B-mediated regulation of hypoxia-inducible factor 1α(HIF-1α).Cycloheximide chase and ubiquitination assays were used to assess the effect of METTL7B on HIF-1α protein stability,and the involvement of ubiquitin-specific protease 28(USP28)was further examined.Lactate production and glucose uptake assays were performed to assess the impact of METTL7B and HIF-1α on glycolytic activity.Results:METTL7B was significantly upregulated in PTC tissues(P<0.05)and positively correlated with lymph node metastasis(P<0.05).METTL7B knockdown markedly suppressed PTC cell proliferation and colony formation(all P<0.05),and markedly reduced the growth rate of PTC xenograft tumors in nude mice,with tumor volumes smaller than those in the control group(P<0.05).Bioinformatics analysis suggested a strong association between METTL7B and the HIF-1α signaling pathway.METTL7B knockdown reduced HIF-1α protein levels without affecting its mRNA expression.Mechanistically,METTL7B inhibited the ubiquitination and degradation of HIF-1α,thereby maintaining its protein stability,and this process was mediated by USP28.Functional assays demonstrated that METTL7B enhanced glycolytic activity and malignant phenotypes of PTC cells by upregulating glycolysis-related genes through the USP28/HIF-1α axis.Conclusion:METTL7B promotes glycolysis and malignant progression in PTC cells by stabilizing HIF-1α through USP28-mediated deubiquitination.
徐逢雨;谢秋萍
浙江大学医学院附属第二医院甲状腺外科,浙江 杭州 310009浙江大学医学院附属第二医院甲状腺外科,浙江 杭州 310009
医药卫生
甲状腺乳头状癌甲基转移酶样蛋白7B低氧诱导因子1α泛素特异性蛋白酶28糖酵解裸鼠
Papillary thyroid carcinomaMethyltransferase-like protein 7BHypoxia-inducible factor-1αUbiquitin-specific protease 28GlycolysisNude mice
《浙江大学学报（医学版）》 2026 (6)
528-539,12
国家自然科学基金(82303597)The study was supported by National Natural Science Foundation of China(82303597)
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