Deubiquitinating enzyme MINDY1 is an independent risk factor for the maintenance of stemness and poor prognosis in liver cancer cells / 中华肝脏病杂志

Objective: To explore the key deubiquitinating enzymes that maintain the stemness of liver cancer stem cells and provide new ideas for targeted liver cancer therapy. Methods: The high-throughput CRISPR screening technology was used to screen the deubiquitinating enzymes that maintain the stemness of liver cancer stem cells. RT-qPCR and Western blot were used to analyze gene expression levels. Stemness of liver cancer cells was detected by spheroid-formation and soft agar colony formation assays. Tumor growth in nude mice was detected by subcutaneous tumor-bearing experiments. Bioinformatics and clinical samples were examined for the clinical significance of target genes. Results: MINDY1 was highly expressed in liver cancer stem cells. The expression of stem markers, the self-renewal ability of cells, and the growth of transplanted tumors were significantly reduced and inhibited after knocking out MINDY1, and its mechanism of action may be related to the regulation of the Wnt signaling pathway. The expression level of MINDY1 was higher in liver cancer tissues than that in adjacent tumors, which was closely related to tumor progression, and its high expression was an independent risk factor for a poor prognosis of liver cancer. Conclusion: The deubiquitinating enzyme MINDY1 promotes stemness in liver cancer cells and is one of the independent predictors of poor prognosis in liver cancer.

Deubiquitinase MYSM1 Regulates Differentiation of Human B Cells to Plasma Cells / 中国实验血液学杂志

OBJECTIVE@#To study the regulatory effect of deubiquitinase MYSM1 on differentiation of B cells to plasma cells.@*METHODS@#The interfering and overexpression plasmids of MYSM1 were constructed and then the corresponding lentiviruses were packaged. Human CD19 B cells were isolated from human peripheral blood with Miltenyi B cell isolation kit. Purified CD19 B cells were transduced with lentiviruses and then treated with LPS, the CD138 expression was detected by flow cytometry. The expression of transcription factor was determined by quantitative PCR.@*RESULTS@#The differentiation of B cells to plasma cells was enhanced after interfering in MYSM1 expression. Quantitative PCR showed that mRNA levels of Pax5 and Bach2 in cells with interfering in MYSM1 were much lower than their counterpart (P＜0.01), and mRNA levels of Prdm1 and Xbp1 in cells with interfering in MYSM1 were much higher than their counterpart (P＜0.01). On the contrary, the differentiation of B cells to plasma cells was inhibited after the overexpression of MYSM1. Quantitative PCR showed that mRNA levels of Pax5 and Bach2 in cells with MYSM1 overexpression were higher than those in control cells (P＜0.01), and mRNA levels of Prdm1 and Xbp1 in cells with MYSM1 overexpression were much lower than those in their counterpart (P＜0.01).@*CONCLUSION@#MYSM1 negatively regulates differentiation of human B cells to plasma cells.

Deubiquitinases as pivotal regulators of T cell functions / 医学前沿

T cells efficiently respond to foreign antigens to mediate immune responses against infections but are tolerant to self-tissues. Defect in T cell activation is associated with severe immune deficiencies, whereas aberrant T cell activation contributes to the pathogenesis of diverse autoimmune and inflammatory diseases. An emerging mechanism that regulates T cell activation and tolerance is ubiquitination, a reversible process of protein modification that is counter-regulated by ubiquitinating enzymes and deubiquitinases (DUBs). DUBs are isopeptidases that cleave polyubiquitin chains and remove ubiquitin from target proteins, thereby controlling the magnitude and duration of ubiquitin signaling. It is now well recognized that DUBs are crucial regulators of T cell responses and serve as potential therapeutic targets for manipulating immune responses in the treatment of immunological disorders and cancer. This review will discuss the recent progresses regarding the functions of DUBs in T cells.