A20-mediated degradation of RNF138 restricts MYD88^L265P oncogenic activity. (A-B) Effects of A20 depletion on RNF138 expression and MYD88^L265P ubiquitination (A) and downstream signaling (B) in RPCI.WM1 cells. (C-D) Effects of A20 and/or RNF138 depletion in cell viability and colony formation. RPCI.WM1 cells were transfected with shRNAs targeting A20, RNF138, or both, before subjected to MTS (C) and CFU (D) assays. The bar represents 50 μm. ***P < .001. (E-G) Tumorigenesis of RPCI.WM1 cells with A20 and/or RNF138 knockdown. Cells were transfected with shRNAs targeting A20, RNF138, or both, and injected into NSG mice. The tumors were analyzed as described in panels H-J of Figure 2. Ki67 was stained with DAB as the chromogen (brown) (G). The bar in panel F represents 1 cm; panel G, 25 μm. *P < .05, ***P < .001. WCE, whole-cell extract.