The innate sensor ZBP1-IRF3 axis regulates cell proliferation in multiple myeloma

Multiple myeloma is a malignancy of plasma cells (PC) initiated and driven by primary and secondary genetic events. Nevertheless, myeloma PC survival and proliferation might be sustained by non-genetic drivers. Z-DNA-binding protein 1 (ZBP1; also known as DAI) is an interferon-inducible, Z-nucleic acid sensor that triggers RIPK3-MLKL-mediated necroptosis in mice. ZBP1 also interacts with TBK1 and the transcription factor IRF3 but the function of this interaction is unclear, and the role of ZBP1-IRF3 axis in cancer is not known. Here we show that ZBP1 is selectively expressed in late B cell development in both human and mouse cells and it is required for optimal T-cell-dependent humoral immune responses. In myeloma PC, interaction of constitutively expressed ZBP1 with TBK1 and IRF3 results in IRF3 phosphorylation. IRF3 directly binds and activates cell cycle genes, in part through co-operation with the PC lineage-defining transcription factor IRF4, and thereby promoting myeloma cell proliferation. This generates a novel, potentially therapeutically targetable and relatively selective myeloma cell addiction to the ZBP1-IRF3 axis. Our data also show a non-canonical function of constitutive ZBP1 in human cells and expand our knowledge of the role of cellular immune sensors in cancer biology

A wolf in sheep's clothing: enteropathy associated T‐cell lymphoma involving a nasal polyp masquerading as primary mucosal CD30 ‐positive T‐cell lymphoproliferative disorder

Publication status: PublishedFunder: BBSRC DTP PhD studentshipFunder: NIHR Biomedical Research Centre, Royal Marsden NHS Foundation Trust/Institute of Cancer Research; doi: http://dx.doi.org/10.13039/100014461Funder: Cancer Research UK; doi: http://dx.doi.org/10.13039/501100000289Funder: Blood Cancer UK; doi: http://dx.doi.org/10.13039/50110001557

A wolf in sheep's clothing: enteropathy associated T-cell lymphoma involving a nasal polyp masquerading as primary mucosal CD30-positive T-cell lymphoproliferative disorder.

CASE SUMMARY An 81-year-old woman presented with nose bleeds and a left anterior nasal septal polyp. Excision biopsy revealed a mucosal lymphoid infiltrate with features of anaplastic large cell lymphoma (ALCL) (Figure 1A). The neoplastic cells were positive for CD45, CD30, EMA (focal), CD3 (variable), CD2, CD25, pSTAT3, TIA1 (focal) and granzyme-B (focal), but negative for ALK, CD5, CD7, CD4, CD8, TCR, CD103 and B-cell markers. Ki67 proliferation approached 100%. EBV encoded small RNA was negative by in situ hybridisation. Fluorescent in situ hybridisation analysis did not detect DUSP22 or TP63 rearrangements. In view of the clinically localised disease, the proffered diagnosis was mucosal CD30+ T-cell lymphoproliferative disorder (T-LPD) akin to primary cutaneous CD30+ T-LPD, with the caveat imaging should confirm localised disease, excluding systemic ALK-negative ALCL

The innate sensor ZBP1-IRF3 axis regulates cell proliferation in multiple myeloma

Multiple myeloma is a malignancy of plasma cells initiated and driven by primary and secondary genetic events. However, myeloma plasma cell survival and proliferation might be sustained by non-genetic drivers. Z-DNA-binding protein 1 (ZBP1; also known as DAI) is an interferon-inducible, Z-nucleic acid sensor that triggers RIPK3-MLKL-mediated necroptosis in mice. ZBP1 also interacts with TBK1 and the transcription factor IRF3 but the function of this interaction is unclear, and the role of the ZBP1-IRF3 axis in cancer is not known. Here we show that ZBP1 is selectively expressed in late B-cell development in both human and murine cells and it is required for optimal T-cell-dependent humoral immune responses. In myeloma plasma cells, the interaction of constitutively expressed ZBP1 with TBK1 and IRF3 results in IRF3 phosphorylation. IRF3 directly binds and activates cell cycle genes, in part through co-operation with the plasma cell lineage-defining transcription factor IRF4, thereby promoting myeloma cell proliferation. This generates a novel, potentially therapeutically targetable and relatively selective myeloma cell addiction to the ZBP1-IRF3 axis. Our data also show a non-canonical function of constitutive ZBP1 in human cells and expand our knowledge of the role of cellular immune sensors in cancer biology. © 2022 Ferrata Storti Foundation

Non-IG::MYC in diffuse large B-cell lymphoma confers variable genomic configurations and MYC transactivation potential

MYC translocation occurs in 8–14% of diffuse large B-cell lymphoma (DLBCL), and may concur with BCL2 and/or BCL6 translocation, known as double-hit (DH) or triple-hit (TH). DLBCL-MYC/BCL2-DH/TH are largely germinal centre B-cell like subtype, but show variable clinical outcome, with IG::MYC fusion significantly associated with inferior survival. While DLBCL-MYC/BCL6-DH are variable in their cell-of-origin subtypes and clinical outcome. Intriguingly, only 40-50% of DLBCL with MYC translocation show high MYC protein expression (>70%). We studied 186 DLBCLs with MYC translocation including 32 MYC/BCL2/BCL6-TH, 75 MYC/BCL2-DH and 26 MYC/BCL6-DH. FISH revealed a MYC/BCL6 fusion in 59% of DLBCL-MYC/BCL2/BCL6-TH and 27% of DLBCL-MYC/BCL6-DH. Targeted NGS showed a similar mutation profile and LymphGen genetic subtype between DLBCL-MYC/BCL2/BCL6-TH and DLBCL-MYC/BCL2-DH, but variable LymphGen subtypes among DLBCL-MYC/BCL6-DH. MYC protein expression is uniformly high in DLBCL with IG::MYC, but variable in those with non-IG::MYC including MYC/BCL6-fusion. Translocation breakpoint analyses of 8 cases by TLC-based NGS showed no obvious genomic configuration that enables MYC transactivation in 3 of the 4 cases with non-IG::MYC, while a typical promoter substitution or IGH super enhancer juxtaposition in the remaining cases. The findings potentially explain variable MYC expression in DLBCL with MYC translocation, and also bear practical implications in its routine assessment