The new and increasingly studied concept of immunogenic cell death (ICD) revealed a previously unknown perspective of the various regulated cell death (RCD) modalities, elucidating their immunogenic properties and rendering obsolete the notion that immune stimulation is solely the outcome of necrosis. A distinct characteristic of ICD is the release of danger-associated molecular patterns (DAMPs) by dying and/or dead cells. Thus, several members of the DAMP family, such as the well-characterized heat shock proteins (HSPs) HSP70 and HSP90, the high-mobility group box 1 protein and calreticulin, and the thymic polypeptide prothymosin α (proTα) and its immunoreactive fragment proTα(100–109), are being studied as potential diagnostic tools and/or possible therapeutic agents. Here, we present the basic aspects and mechanisms of both ICD and other immunogenic RCD forms; denote the role of DAMPs in ICD; and further exploit the relevance of human proTα and proTα(100–109) in ICD, highlighting their possible clinical applications. Furthermore, we present the preliminary results of our in vitro studies, which show a direct correlation between the concentration of proTα/proTα(100–109) and the levels of cancer cell apoptosis, induced by anticancer agents and γ-radiation.

The basic principle that deeper therapeutic responses lead to better clinical outcomes in cancer has emerged technologies capable of detecting rare residual tumor cells. The need for ultra-sensitive approaches for minimal residual disease (MRD) detection is particularly evident in Multiple Myeloma (MM), where patients will ultimately relapse despite the achievement of complete remission, which is commonplace due to remarkable therapeutic advances. Consequently, current response criteria on MM have been amended based on MRD status and MRD negativity is now considered the most dominant prognostic factor and the most valuable indicator for a subsequent relapse. However, there are particular limitations and several aspects for MRD assessment that remain open. This review summarizes current data on MRD in the clinical management of MM, highlights open issues and discusses the challenges and the endless opportunities arising for both patients and clinicians. Furthermore, it focuses on the current status of MRD in clinical trials, its dynamics in addressing debatable aspects in the clinical handling and its potential role as the prevailing factor for future MRD-driven tailored therapies.

Bortezomib and dexamethasone with cyclophosphamide (CyBorD) or melphalan (BMDex) are commonly used primary treatments for light-chain (AL) amyloidosis, but limited data exist on bortezomib with immunomodulatory drug combinations. We report our experience with primary therapy with a bortezomib, lenalidomide, and dexamethasone (VRD) “light” regimen in 34 consecutive patients with AL amyloidosis. The majority (79%) had cardiac involvement, 15% and 23% were Mayo stage 3A and 3B, respectively, and 54% had renal involvement. After the first VRD cycle, 71% of patients achieved a hematologic response (44% at least very good partial response [VGPR]). On intent to treat, 11 (32%) achieved a complete response (of whom 5 of 11 were minimal residual disease [MRD] negative at 10⁻⁵), 17 (50%) a VGPR, and 2 (7%) a partial response. The 12-month survival was 73%. Starting lenalidomide dose was 5 mg in 86% of patients. Hematologic toxicity was mild; nonhematologic toxicities included rash (grade 3/4 [16%]), infections (grade ≥3 [12%]), constipation (grade ≥3 [9%]), and peripheral neuropathy (grade 2 [20%]); 37.5% of patients required lenalidomide dose reduction, 27% discontinued lenalidomide, 38% required bortezomib dose reduction, and 12% discontinued bortezomib. We compared VRD to CyBorD in 68 patients matched for Mayo stage and baseline difference between involved minus uninvolved serum free light chain levels, and observed a trend for deeper response at 3 and 6 months with VRD. In conclusion, VRD can be an active regimen for newly diagnosed patients with AL amyloidosis able to induce very deep hematologic responses at the expense of increased toxicity.

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 noncanonical function of constitutive ZBP1 in human cells and expand our knowledge of the role of cellular immune sensors in cancer biology.