TAK1 is a druggable kinase for diffuse large B-cell lymphoma

Combining structure-based pharmacophore modeling and machine learning for the identification of novel BTK inhibitors

Bruton's tyrosine kinase (BTK) is a critical enzyme which is involved in multiple signaling pathways that regulate cellular survival, activation, and proliferation, making it a major cancer therapeutic target. We applied the novel integrated structure-based pharmacophore modeling, machine learning, and other in silico studies to screen the Korean chemical database (KCB) to identify the potential BTK inhibitors (BTKi). Further evaluation of these inhibitors on three different human cancer cell lines showed significant cell growth inhibitory activity. Among the 13 compounds shortlisted, four demonstrated consistent cell inhibition activity among breast, gastric, and lung cancer cells (IC50 below 3 μM). The selected compounds also showed significant kinase inhibition activity (IC50 below 5 μM). The current study suggests the potential of these inhibitors for targeting BTK malignant tumors.

USP7 sustains an active epigenetic program via stabilizing MLL2 and WDR5 in diffuse large B-cell lymphoma

Activated B-cell-like (ABC)-diffuse large B-cell lymphoma (ABC-DLBCL) is a common subtype of non-Hodgkin's lymphoma with poor prognosis. The survival of ABC-DLBCL relies on constitutive activation of BCR signaling, but the underlying molecular mechanism is not fully addressed. By mining The Cancer Genome Atlas database, we found that the expression of ubiquitin-specific protease 7 (USP7) is significantly elevated in three cancer types including DLBCL. Interestingly, unlike germinal center B-cell-like (GCB)-DLBCL, ABC-DLBCL shows upregulated expression of USP7. Inhibiting the enzymatic activity of USP7 (P22077) has a drastic effect on ABC-DLBCL, but not GCB-DLBCL cells. Compared to GCB-DLBCL, ABC-DLBCL cells show transcriptional upregulation of multiple components of BCR-signaling. USP7 inhibition significantly reduces the expression of upregulated components of BCR signaling. Mechanistically, USP7 inhibition greatly reduces the methylation of histone 3 on lysine 4 (H3K4me2), which is an epigenetic marker for active enhancers. USP7 inhibition greatly reduces the protein level of WDR5 and MLL2, key components of lysine-specific methyltransferase complex (complex of proteins associated with Set1 [COMPASS]). In ABC-DLBCL cells, USP7 stabilizes WDR5 and MLL2. In patients, the expression of USP7 is significantly associated with components of BCR signaling (LYN, SYK, BTK, PLCG2, PRKCB, MALT1, BCL10, and CARD11) and targets of BCR signaling (MYC and IRF4). In summary, we demonstrated an essential role of USP7 in ABC-DLBCL by organizing an oncogenic epigenetic program via stabilization of WDR5 and MLL2. Targeting USP7 might be a novel and efficient approach to treat patients with ABC-DLBCL and it might be better than targeting individual components such as BTK in BCR signaling.