Song Xingchao, Li Wenjin, Tian Chunyan, Ma Xiao, Yang Weibin, Zhou Jiahua
Hepatobiliopancreatic Center, The Affiliated Zhongda Hospital, School of Medicine, Southeast University, Nanjing, China; Department of Hepatobiliopancreatic Surgery, Xuzhou First People's Hospital, Xuzhou, China.
Department of Hepatobiliopancreatic Surgery, Xuzhou First People's Hospital, Xuzhou, China.
Biomol Biomed. 2024 Dec 11;25(1):144-154. doi: 10.17305/bb.2024.10962.
The novel deubiquitinase enzyme, motif interacting with ubiquitin-containing novel DUB family-1 (MINDY1), is highly expressed in liver cancer tissues and plays a crucial role in maintaining the stemness of liver cancer cells. Programmed death ligand-1 (PD-L1) is an immunosuppressive molecule overexpressed by tumour cells. The potential role of MINDY1 in inhibiting the stemness of liver cancer cells by deubiquitinating PD-L1 has not yet been reported. To investigate the mechanism by which MINDY1 mediates immune escape in liver cancer through the regulation of PD-L1 ubiquitination, we examined the expression levels of MINDY1 and PD-L1 in liver cancer and adjacent tissues from 50 hepatocellular carcinoma (HCC) patients using protein imprinting and immunohistochemistry. We analyzed the relationship between the expression levels of MINDY1 and PD-L1 in liver cancer tissues and their correlation with the 5-year tumor-free survival rates of patients. Subsequently, MINDY1 expression was knocked down in Huh7 cells using small interfering RNA (siRNA) interference or upregulated through transfection with a MINDY1 overexpression plasmid. The effects of MINDY1 knockdown or overexpression on the proliferation, apoptosis, migration, and invasion of HCC cells, as well as the regulation of PD-L1 binding and ubiquitination, were assessed. The 5-year tumor-free survival rates were significantly lower in both the high MINDY1 expression group and the high PD-L1 expression group (χ2 = 4.919 and 13.158, respectively). A significant difference in survival was observed between the high and low MINDY1 expression groups (χ2= 27.415). MINDY1 was found to directly interact with PD-L1, with MINDY1 gene knockdown promoting PD-L1 ubiquitination and MINDY1 overexpression inhibiting PD-L1 ubiquitination. All comparisons yielded statistically significant results (P < 0.05). In conclusion, MINDY1 inhibits the malignant progression of liver cancer by inhibiting PD-L1 ubiquitination and mediating immune escape.
新型去泛素化酶，即与含泛素的新型去泛素酶家族-1相互作用的基序（MINDY1），在肝癌组织中高表达，并在维持肝癌细胞的干性方面发挥关键作用。程序性死亡配体-1（PD-L1）是一种由肿瘤细胞过度表达的免疫抑制分子。MINDY1通过去泛素化PD-L1抑制肝癌细胞干性的潜在作用尚未见报道。为了研究MINDY1通过调节PD-L1泛素化介导肝癌免疫逃逸的机制，我们采用蛋白质印迹法和免疫组织化学法检测了50例肝细胞癌（HCC）患者肝癌组织及癌旁组织中MINDY1和PD-L1的表达水平。我们分析了肝癌组织中MINDY1和PD-L1的表达水平之间的关系及其与患者5年无瘤生存率的相关性。随后，使用小干扰RNA（siRNA）干扰在Huh7细胞中敲低MINDY1表达，或通过转染MINDY1过表达质粒上调其表达。评估了MINDY1敲低或过表达对肝癌细胞增殖、凋亡、迁移和侵袭的影响，以及对PD-L1结合和泛素化的调节。高MINDY1表达组和高PD-L1表达组的5年无瘤生存率均显著较低（分别为χ2 = 4.919和13.158）。在高MINDY1表达组和低MINDY1表达组之间观察到生存存在显著差异（χ2 = 27.415）。发现MINDY1与PD-L1直接相互作用，MINDY1基因敲低促进PD-L1泛素化，MINDY1过表达抑制PD-L1泛素化。所有比较均产生统计学显著结果（P < 0.05）。总之，MINDY1通过抑制PD-L1泛素化和介导免疫逃逸来抑制肝癌的恶性进展。
