USP21 promotes cell proliferation by maintaining the EZH2 level in diffuse large B‐cell lymphoma

BACKGROUND: Diffuse large B‐cell lymphoma (DLBCL) is the most common category of non‐Hodgkin lymphoma (NHL). However, the underlying molecular mechanism of DLBCL remains unclear. METHODS: Real‐time PCR and Western blot analysis were performed to assess the expression of ubiquitin‐specific peptidase 21 (USP21) or enhancer of zeste 2 polycomb repressive complex 2 subunit (EZH2). CCK8 assay and cell death staining were carried out to examine the role of USP21 in cell proliferation and cell death, respectively. RESULTS: We found that the deubiquitinase USP21 was highly expressed in the DLBCL lymphoid tissue. The expression of USP21 promoted DLBCL cell proliferation, while it had no obvious effect on cell death. In addition, we found that USP21 regulated cell proliferation via cysteine 221, the catalytic site of USP21. Furthermore, we identified that USP21 could stabilize EZH2, a protein required for germinal center formation and lymphoma formation. CONCLUSION: The deubiquitinase USP21 promotes cell proliferation by maintaining the EZH2 protein level in DLBCL.