Activated B-cell-like diffuse large B-cell lymphoma (ABC-DLBCL) is driven by aberrant activation of the B-cell receptor (BCR) and the TLR/MyD88 signaling pathways. The heat-shock protein HSP110 is a candidate for their regulation as it stabilizes MyD88. However, its role in overall BCR signaling remains unknown. Here, we used first-in-class HSP110 inhibitors to address this question. HSP110 inhibitors decreased the survival of several ABC-DLBCL cell lines in vitro and in vivo, and reduced the phosphorylation of BCR signaling kinases, including BTK and SYK. We identified an interaction between HSP110 and SYK and demonstrated that HSP110 promotes SYK phosphorylation. Finally, the combination of the HSP110 inhibitor with the PI3K inhibitor copanlisib decreases SYK/BTK and AKT phosphorylation synergistically, leading to suppression of tumor growth in cell line xenografts and strong reduction in patient-derived xenografts. In conclusion, by regulating the BCR/TLR signaling pathway, HSP110 inhibitors are potential drug candidates for ABC-DLBCL patients.

• MeSH
• chinazoliny MeSH
• difúzní velkobuněčný B-lymfom * farmakoterapie   metabolismus   patologie   MeSH
• fosforylace účinky léků   MeSH
• kinasa Syk * antagonisté a inhibitory   metabolismus   MeSH
• lidé MeSH
• myši SCID MeSH
• myši MeSH
• nádorové buněčné linie MeSH
• nádorové buňky kultivované MeSH
• proteiny tepelného šoku HSP110 * metabolismus   MeSH
• pyrimidiny farmakologie   MeSH
• receptory antigenů B-buněk * metabolismus   MeSH
• signální transdukce * účinky léků   MeSH
• xenogenní modely - testy protinádorové aktivity * MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• chinazoliny MeSH
• copanlisib MeSH Prohlížeč
• kinasa Syk * MeSH
• proteiny tepelného šoku HSP110 * MeSH
• pyrimidiny MeSH
• receptory antigenů B-buněk * MeSH
• SYK protein, human MeSH Prohlížeč

Diffuse large B-cell lymphoma (DLBCL) is an aggressive disease that exhibits constitutive activation of phosphoinositide 3-kinase (PI3K) driven by chronic B-cell receptor signaling or PTEN deficiency. Since pan-PI3K inhibitors cause severe side effects, we investigated the anti-lymphoma efficacy of the specific PI3Kβ/δ inhibitor AZD8186. We identified a subset of DLBCL models within activated B-cell-like (ABC) and germinal center B-cell-like (GCB) DLBCL that were sensitive to AZD8186 treatment. On the molecular level, PI3Kβ/δ inhibition decreased the pro-survival NF-κB and AP-1 activity or led to downregulation of the oncogenic transcription factor MYC. In AZD8186-resistant models, we detected a feedback activation of the PI3K/AKT/mTOR pathway following PI3Kβ/δ inhibition, which limited AZD8186 efficacy. The combined treatment with AZD8186 and the mTOR inhibitor AZD2014 overcame resistance to PI3Kβ/δ inhibition and completely prevented outgrowth of lymphoma cells in vivo in cell line- and patient-derived xenograft mouse models. Collectively, our study reveals that subsets of DLBCLs are addicted to PI3Kβ/δ signaling and thus identifies a previously unappreciated role of the PI3Kβ isoform in DLBCL survival. Furthermore, our data demonstrate that combined targeting of PI3Kβ/δ and mTOR is effective in all major DLBCL subtypes supporting the evaluation of this strategy in a clinical trial setting.

• MeSH
• difúzní velkobuněčný B-lymfom * patologie   MeSH
• fosfatidylinositol-3-kinasy * metabolismus   MeSH
• lidé MeSH
• myši MeSH
• nádorové buněčné linie MeSH
• signální transdukce MeSH
• TOR serin-threoninkinasy metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• AZD8186 MeSH Prohlížeč
• fosfatidylinositol-3-kinasy * MeSH
• MTOR protein, human MeSH Prohlížeč
• TOR serin-threoninkinasy MeSH