The role of necroptosis as a possible therapeutic target in multiple myeloma: the emerging roles of necroptosis

1 Introduction

Multiple myeloma (MM) is a hematological malignancy resulting from terminally differentiated B cells and ranks as the second most diagnosed hematological cancer globally. MM is characterized by the clonal expansion of atypical plasma cells within the bone marrow (BM), leading to the excessive synthesis and secretion of monoclonal immunoglobulins or free light chains, collectively referred to as M protein (1). This pathological overproduction not only disrupts normal hematopoiesis but also contributes to systemic complications such as osteolytic bone disease, renal dysfunction, anemia, and hypercalcemia. The underlying molecular pathogenesis of MM involves complex genetic and epigenetic alterations, as well as interactions with the bone marrow microenvironment, and dysregulated signaling pathways that collectively drive the survival, proliferation, and immune evasion of malignant plasma cells (2). Epidemiological data indicate that over 230,000 MM cases have been diagnosed globally in the past five years, with a standardized incidence rate of approximately 1.5 per 100,000 individuals. The median age at diagnosis ranges from 66 to 70 years; however, a significant proportion (approximately 37%) of patients are younger than 65, reflecting a broader age distribution than previously recognized (3).

Historically, the Durie-Salmon staging system (1975) was used to stratify disease burden based on clinical and laboratory parameters. This was later refined into the International Staging System (ISS) in 2005, which remains the most widely used prognostic tool in current clinical practice due to its simplicity and prognostic reliability (2, 3). Therapeutic advancements over the past two decades have dramatically transformed the management and prognosis of MM. Frontline treatment modalities now include proteasome inhibitors (PIs), such as ixazomib, carfilzomib, and bortezomib, as well as immunomodulatory drugs (IMiDs), including pomalidomide, lenalidomide, and thalidomide. Despite these improvements, MM remains an incurable disease for most patients due to the frequent development of therapeutic resistance, disease relapse, and clonal evolution, underscoring the need for novel molecularly targeted strategies (4).

Modern therapeutic paradigms in MM have progressively evolved beyond the conventional reliance on apoptosis induction, encompassing a broader spectrum of regulated cell death (RCD) modalities, such as necroptosis, ferroptosis, and pyroptosis, to overcome intrinsic and acquired drug resistance. Apoptosis and autophagy-dependent cell death represent fundamental RCD subtypes that are essential for maintaining cellular homeostasis by selectively eliminating damaged or dysfunctional cells. Their controlled activation has historically served as a cornerstone of anticancer therapy (1, 2). However, accumulating evidence indicates that many malignancies, including MM, acquire resistance to apoptosis via complex molecular alterations that disrupt pro-apoptotic signaling and promote the expression of anti-apoptotic proteins. This dysregulation enables malignant plasma cells to evade programmed cell death, sustain uncontrolled proliferation, and develop resistance to conventional therapeutic regimens. Consequently, there is a growing emphasis on exploring non-apoptotic RCD pathways as alternative cytotoxic mechanisms to effectively target apoptosis-refractory myeloma cells and enhance therapeutic efficacy (3, 5).

Necroptosis, a caspase-independent and immunogenic form of regulated cell death, has emerged as a promising alternative mechanism to overcome apoptosis resistance in MM. Unlike apoptosis, necroptosis relies on the activation of receptor-interacting protein kinases (RIPK1 and RIPK3) and the effector protein MLKL, which can induce cell death even in contexts where apoptosis is resistant (6). Nonetheless, downregulation or epigenetic silencing of RIPK3 and MLKL in MM limits necroptotic activation, suggesting that restoring their expression could re-sensitize resistant cells to treatment. Significantly, necroptosis also enhances tumor immunogenicity by releasing damage-associated molecular patterns (DAMPs), stimulating inflammatory and immune responses that may counteract immune evasion (7). Several therapeutic agents, including SMAC mimetics, histone deacetylase (HDAC) inhibitors, and proteasome inhibitors such as bortezomib, have been shown to modulate necroptosis and synergize with standard therapies (8). Overall, targeting necroptotic signaling represents a promising strategy to bypass apoptosis resistance, enhance chemosensitivity, and improve therapeutic outcomes in multiple myeloma. Integrating non-apoptotic cell death mechanisms into MM treatment paradigms holds considerable potential to overcome current therapeutic limitations (Table 1) (1).

Table 1. Comparative characteristics of apoptosis and necroptosis based on the key molecular, morphological, and immunological features.

On the other hand, during necroptosis, tumor cells release DAMPs such as HMGB1, ATP, and nucleic acids, which act as potent immunogenic signals that activate dendritic cells (DCs), promote antigen cross-presentation, and stimulate cytotoxic CD8⁺ T-cell responses (9). This immunogenic nature of necroptosis can convert immunologically “cold” tumors into “hot” ones, enhancing their responsiveness to immune checkpoint blockade and other immunotherapies. However, the exact necroptotic mechanisms that drive antitumor immunity can, when chronically or aberrantly activated, foster a pro-tumorigenic inflammatory milieu. Persistent DAMP and cytokine release, particularly TNF-α, IL-6, and IL-1β, can recruit immunosuppressive myeloid-derived suppressor cells (MDSCs) and tumor-associated macrophages (TAMs), inhibit the function of cytotoxic T cells, and promote angiogenesis, extracellular matrix remodeling, and metastatic dissemination (9, 10).

Elucidating the molecular regulation of necroptosis within the context of MM holds significant potential for the development of synergistic therapeutic approaches, particularly for patients with relapsed or refractory disease. However, the overall impact of necroptosis on tumor progression therefore depends critically on contextual factors, including the intensity and duration of RIPK3–MLKL activation, the specific cell types undergoing necroptosis, and the composition of the tumor microenvironment (11). Consequently, therapeutic strategies aimed at harnessing necroptosis in cancer must be carefully regulated in both space and time, with biomarker-guided approaches to maximize immunogenic, anti-tumor effects while minimizing chronic inflammation and immune suppression. This review critically examines the emerging evidence regarding the role of necroptosis in MM pathobiology and its implications for novel treatment strategies. Continued research into the molecular regulation of necroptosis in the context of myeloma may lead to synergistic treatment regimens, especially for patients with relapsed or refractory disease (12).

2 Necroptosis in multiple myeloma

2.1 Mechanism of necroptosis

Necroptosis is a tightly regulated form of programmed necrosis that functions as an alternative cell death pathway and is primarily triggered by virus infection, infection, pathogens, stress, chemicals, and various cellular receptors, including death receptors (such as tumor necrosis factor receptor 1 (TNFR1), Fas), pattern-recognition receptors like Toll-like receptors (TLR3 and TLR4), interferon receptors (IFNR) and cytosolic sensors such as ZBP1 and STING (Figure 1) (13). Among the initiating pathways, TNFR1-mediated receptor-interacting protein kinase-1 (RIPK1) activation is the most extensively characterized. Upon tumor necrosis factor-alpha (TNF-α) stimulation, TNFR1 undergoes a conformational change that facilitates the recruitment of several adaptor proteins to form membrane-bound signaling complex I, consisting of TNFR1-associated death domain protein (TRADD), RIPK1, TNF receptor–associated factor 2 (TRAF2), and the cellular inhibitors of apoptosis (cIAP1/2) to form membrane-associated complex I (14).

Within Complex I, RIPK1 undergoes extensive polyubiquitination through both K63-linked and M1-linked ubiquitin chains, a modification catalyzed primarily by cIAP1/2 and the linear ubiquitin chain assembly complex (LUBAC). These ubiquitin modifications stabilize Complex I at the plasma membrane and create a scaffold for the recruitment of downstream signaling molecules, thereby promoting the activation of pro-survival NF-κB signaling cascades. Conversely, the removal of these ubiquitin chains by deubiquitinating enzymes, such as cylindromatosis (CYLD) or A20, disrupts the integrity of Complex I, leading to its disassembly and release from the membrane. The liberated components subsequently reassemble in the cytosol to form Complex II, which incorporates the adaptor protein Fas-associated death domain (FADD) and functions as a central platform for death signaling (14, 15).

Under normal conditions, complex II recruits and activates caspase-8, leading to apoptotic cell death. At this critical decision point, the activity of caspase-8 determines the cell’s fate. When active, caspase-8 cleaves RIPK1 and RIPK3, redirecting the pathway toward apoptosis. However, when caspase-8 activity is genetically ablated, pharmacologically inhibited (e.g., by zVAD-fmk), or otherwise impaired, apoptosis is inhibited (Table 1). Following that, RIPK1 interacts with RIPK3 via their RIP homotypic interaction motifs (RHIMs), driving the assembly of the high-molecular-weight amyloid-like necrosome (16). Within this signaling hub, RIPK3 phosphorylates its downstream effector MLKL on specific serine/threonine residues, triggering MLKL oligomerization and translocation to the plasma membrane. Membrane-associated MLKL disrupts integrity either by forming pore-like structures or by activating cation channels (e.g., TRPM7) that mediate Ca²⁺ and Na⁺ influx, leading to osmotic swelling, membrane rupture, and the release of damage-associated molecular patterns (DAMPs) that provoke robust inflammatory responses (17). Additionally, mitochondrial fragmentation mediated by the phosphatase PGAM5 and the GTPase DNM1L (also known as DRP1) may contribute to membrane rupture. These events culminate in the release of damage-associated molecular patterns (DAMPs), such as high-mobility group box 1 (HMGB1), adenosine triphosphate (ATP), and nuclear proteins, which elicit robust inflammatory responses (18, 19).

Notably, the necroptotic cascade can be effectively suppressed by MAP kinase-activated protein kinase 2 (MAPKAPK2)-mediated phosphorylation of RIPK1. This modification inhibits RIPK1 activation and disrupts its interaction with RIPK3, thereby preventing the formation of necrosomes. Consequently, MAPKAPK2 is a crucial cell survival checkpoint, modulating the balance between cell survival, apoptosis, and necroptosis. Recent studies have identified several novel molecules as critical mediators within the necroptotic signaling cascade. For instance, Dovey et al. demonstrated that inositol phosphate (IP) kinases encoded by IPMK and ITPK1 are essential for necroptosis (16, 17). In human cells, highly phosphorylated IPs bind to MLKL and displace its auto-inhibitory brace, thereby promoting MLKL oligomerization and subsequent translocation to the plasma membrane. Another regulatory checkpoint involves the cytoplasmic nuclear receptor RARγ; RARγ translocates from the nucleus to the cytosol during TNFα-induced necroptosis, where it facilitates the dissociation of RIPK1 from the TNF-R1–associated Complex I, enabling the assembly of cytosolic Complex II and initiation of death signaling (17).

Post-translational modifications of RIPK1 and RIPK3 serve as additional early checkpoints in TNFα-induced RCD. Degradative ubiquitination of RIPK3, mediated by E3 ligases such as the carboxyl terminus of Hsp70-interacting protein (CHIP) and Pellino E3 ubiquitin protein ligase 1 (PELI1), targets RIPK3 for proteasomal destruction, thereby inhibiting necroptosis (12). In contrast, non-degradative ubiquitination, particularly K63-linked ubiquitination of RIPK1, promotes necroptosis and is regulated by the deubiquitinase A20 and the ubiquitin-binding protein ABIN-1 (7). Similarly, ubiquitination of RIPK3 at lysine 5 supports necrosome formation and necroptosis, an effect that is antagonized by A20-mediated deubiquitination. Interestingly, PELI1, despite its role in targeting RIPK3 for degradation, has also been reported to enhance necroptosis by promoting K63-linked ubiquitination of RIPK1, indicating a context-dependent, dual regulatory role that remains to be fully elucidated. Phosphorylation events also critically modulate RIPK1 activity in the decision between apoptosis and necroptosis. RIPK1 can be phosphorylated by IKKα/β, TAK1, and the downstream mitogen-activated protein kinase–activated protein kinase (MK2), as well as the more recently identified kinases TBK1 and IKKϵ. Phosphorylation by these kinases has been shown to suppress RIPK1’s pro-death function and prevent TNFα-induced RCD, underscoring the importance of multi-layered post-translational regulation in controlling necroptotic signaling (7).

In conclusion, necroptosis is a programmed necrotic pathway that activates when apoptosis is blocked, typically through the TNF-α or related receptor signaling pathway. It relies on RIPK1–RIPK3 necrosome formation and MLKL-driven membrane rupture, releasing inflammatory molecules that alert the immune system. By serving as both a backup death mechanism and a trigger for inflammation, necroptosis represents a double-edged therapeutic target; its activation can eliminate resistant cancer cells, but uncontrolled signaling may promote tissue damage and chronic inflammation (9, 20).

2.2 The role of necroptosis in myeloma

Inducing apoptosis in cancer cells has long been a primary therapeutic strategy aimed at eradicating malignant cells. However, deregulation of apoptotic signaling pathways in cancer, such as the activation of anti-apoptotic mechanisms, enables tumor cells to evade programmed cell death, leading to uncontrolled proliferation and sustained tumor survival. Consequently, the induction of necroptosis, a caspase-independent form of regulated cell death, has emerged as a promising alternative for cancer therapy (21). Furthermore, necroptosis represents a promising therapeutic strategy in MM, particularly in overcoming apoptosis resistance, a common cause of chemoresistance in MM. Unlike apoptosis, necroptosis operates through caspase-independent pathways, making it effective against resistant cells. However, key necroptotic proteins, such as RIPK3 and MLKL, are often downregulated or epigenetically silenced in MM, thereby limiting necroptotic activation (22).

Thus, restoring their expression can resensitize cells to therapy. Moreover, necroptosis is immunogenic, triggering inflammation via DAMP release, which may help counteract immune evasion in MM (23). Agents such as SMAC mimetics, HDAC inhibitors, and proteasome inhibitors (e.g., bortezomib) can modulate necroptosis, and combination strategies with conventional therapies that induce stress pathways show promise (14, (13, 23). Here, we summarize current insights into the signaling mechanisms by which necroptosis contributes to the progression of multiple myeloma and therapeutic response (Table 2).

Table 2. Comprehensive overview of the molecular mechanisms, genetic determinants, and therapeutic relevance of necroptosis in the pathogenesis and treatment of multiple myeloma.

RIPK1, Receptor-Interacting Protein Kinase 1; RIPK3, Receptor-Interacting Protein Kinase 3; MLKL, Mixed Lineage Kinase Domain-Like protein; MM, Multiple Myeloma; DAMPs, Damage-Associated Molecular Patterns; MAPKAPK2, Mitogen-Activated Protein Kinase-Activated Protein Kinase 2; PUFAs, Polyunsaturated Fatty Acids; VEGF, Vascular Endothelial Growth Factor; IL-6, Interleukin-6; SMAC, Second Mitochondria-Derived Activator of Caspases; RHIM, RIP Homotypic Interaction Motif; ZBP1, Z-DNA Binding Protein.

2.2.1 Single nucleotide polymorphisms in necroptosis-associated genes as prognostic biomarkers

Single Nucleotide Polymorphism (SNPs) in key necroptosis-related genes (RIPK1, RIPK3, MAPKAPK2) may influence these processes and impact disease progression and treatment outcomes in MM (24). For instance, the RIPK1 rs9391981 CG variant was linked to reduced overall survival, and the rs2272990 AG variant was associated with a worse prognosis in lenalidomide-treated patients, indicating that RIPK1 variants may affect survival and response to immunomodulatory therapy (25). Similarly, the RIPK3 rs724165 GG genotype correlated with advanced disease stage and higher serum protein levels, while the rs3212243 GG genotype was associated with poor treatment outcomes (25). MAPKAPK2 variants also showed prognostic implications: the rs4073250 AA genotype was independently associated with shorter overall and progression-free survival, and the rs45514798 AA genotype was linked to an increased risk of thalidomide-induced polyneuropathy. Multivariate analysis confirmed that several genotypes (RIPK1 rs9391981 CG, RIPK3 rs724165 GG, RIPK3 rs3212243 GG, and MAPKAPK2 rs4073250 AA) independently predict poorer overall survival (25, 26). These associations underline the potential prognostic utility of necroptosis-related SNPs in MM. Despite being based on a cohort reflective of earlier treatment protocols, the findings are robust due to the treatment-independent nature of the necroptotic pathways. These genetic markers may aid in patient stratification and inform future research into targeted therapies that modulate necroptosis. Nonetheless, larger studies are warranted to validate these associations and clarify their clinical utility (25).

2.2.2 Anti-cancer agents trigger necroptosis in multiple myeloma

The bone marrow homing of myeloma cells is primarily mediated by the stromal cell–derived factor-1 (SDF-1, also known as CXCL12), along with key cell adhesion molecules such as CD44 and very late antigen-4 (VLA-4, also known as integrin α4β1) (27). Adhesion of myeloma cells mediated by VLA-4 or CD44 contributes to the development of drug resistance. Thus, experimental and clinical evidence increasingly support the development of therapeutic strategies to target pathways essential for bone marrow homing and myeloma cell survival (27, 28). The D-amino acid–containing peptide HYD1 (sequence: kikmviswkg), initially identified for its capacity to inhibit cell adhesion, was later shown to suppress autophagy and induce necrotic cell death in multiple myeloma (MM) cells through mechanisms involving reactive oxygen species (ROS) generation, ATP depletion, and disruption of mitochondrial membrane potential (29).

On the other hand, MTI-101 is a promising CD44-binding peptidomimetic (a cyclized peptidomimetic derivative of HYD1) that induces necroptosis in MM cells through mechanisms involving oxidative stress, mitochondrial dysfunction, and necroptosis-like signaling, demonstrating efficacy even within the bone marrow microenvironment (30). The interaction between MM cells and stromal cells within the bone marrow microenvironment plays a critical role in promoting MM cell survival and chemoresistance via secretion of vascular endothelial growth factor (VEGF), interleukin-6 (IL-6), and insulin-like growth factor-1 (IGF-1), which collectively activate the Ras/Raf/MEK/ERK signaling pathway, an axis recognized as essential for MM cell viability (31). Sorafenib induced necroptosis in MM cells, both in vitro and in vivo, in mouse xenograft models, and exerted synergistic activity with bortezomib in human myeloma cell lines (32).

Shikonin induces apoptosis in MM cells at lower concentrations (<5 µM). In contrast, at higher concentrations (10–20 µM), it triggers necroptosis, highlighting its potential as a therapeutic agent for targeting apoptosis-resistant MM cells (33). Lycorine is a natural alkaloid predominantly isolated from plants of the Amaryllidaceae family, particularly from Lycoris radiata. Luo et al. demonstrated that lycorine triggers programmed necrosis in the ARH-77 multiple myeloma cell line via G₁ arrest, mitochondrial dysfunction, ROS-mediated oxidative stress, ATP depletion, and DNA damage, offering a necroptosis-like mechanism to combat apoptosis-resistant MM cells (34). Elevated osteoclast activity drives bone degradation in MM, with pro-inflammatory cytokines like TNF promoting osteoclastogenesis. Smac-mimetics (SMs) inhibit RIPK1 ubiquitination, shifting its role toward apoptosis or necroptosis. Birinapant exhibited greater cytotoxicity in MM compared to LCL-161, predominantly inducing apoptosis with a partial contribution of necroptosis (8). Both compounds effectively inhibited osteoclastogenesis stimulated by bone marrow aspirates from MM patients. Given that LCL-161 is currently undergoing phase 2 clinical trials for MM, these findings suggest that SMs may offer additional clinical benefits by mitigating bone degradation in myeloma patients (8).

Another hallmark of MM is aberrant proteasome activity, against which the proteasome inhibitor bortezomib has markedly improved patient survival rates (35). Notably, chemosensitivity in MM is significantly enhanced when bortezomib is combined with omega-3 polyunsaturated fatty acids (PUFAs), such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). Treatment with PUFAs increased chemosensitivity by modulating the nuclear factor erythroid 2-related factor 2 (NRF2) signaling pathway, a key regulator of GSH degradation, and enhanced necroptosis (36). MG132 is a potent and reversible proteasome inhibitor commonly employed in experimental research to investigate protein degradation, apoptosis, and various cell signaling pathways, particularly those governed by the ubiquitin-proteasome system. Moriwaki et al. demonstrated that proteasome inhibition using MG132 promotes RIP homotypic interaction motif (RHIM)-dependent assembly of a RIPK1–RIPK3–FADD-containing ripoptosome independently of TNF signaling (37).

Furthermore, p62, also known as sequestosome-1 (SQSTM1), is a multifunctional adaptor protein essential for autophagy, cellular signaling, and protein degradation. Recent studies highlight the potential of targeting the ZZ domain of p62 using XRK3F2, a small-molecule inhibitor, to enhance the therapeutic efficacy of bortezomib in MM. This strategy amplifies anti-tumor effects and supports bone health, providing a more comprehensive treatment approach for MM patients, particularly those with bone-related complications (38).

2.2.3 Regulatory pathways, key molecules, and genetic regulation of necroptosis in multiple myeloma

Several studies underscore the potential of necroptosis-related gene signatures as informative biomarkers for both prognostic assessment and therapeutic stratification in MM. Among the key genes, CHMP1A is involved in endosomal sorting and membrane remodeling, processes closely linked to regulated cell death, including necroptosis (39). FAS, a classical death receptor, mediates extrinsic apoptotic signaling and can engage necroptotic pathways when caspase activity is inhibited, illustrating its dual role in cell fate determination (40). JAK3, a member of the Janus kinase family, participates in cytokine receptor signaling and is implicated in promoting survival and proliferation in hematologic malignancies, suggesting that necroptosis may be modulated by upstream inflammatory and growth factor signals (41). HSP90AA1, a molecular chaperone, stabilizes multiple client proteins, including key regulators of necroptosis, thereby influencing the sensitivity of cells to programmed necrotic death (10). In addition, VDAC1, located in the outer mitochondrial membrane, regulates metabolite flux and mitochondrial permeability, linking metabolic status to necroptotic activation and highlighting the role of mitochondrial dynamics in MM progression. STAT3, a transcription factor activated downstream of various cytokine and growth factor pathways, has been implicated in promoting survival, proliferation, and resistance to drugs. Its differential expression suggests that necroptotic signaling may intersect with oncogenic transcriptional programs. Collectively, these genes represent not only potential therapeutic targets for interventions aimed at modulating necroptotic pathways but also provide mechanistic insights into the interplay between regulated cell death, tumor progression, and treatment resistance in MM (9).

DJ-1, also known as Parkinson’s disease-associated protein, is highly expressed in MM cells. High DJ-1 levels correlate with poor clinical outcomes, shorter survival times, and chemoresistance in MM patients. siRNA-mediated knockdown of DJ-1 in MM cell lines triggered robust cell death with features consistent with necroptosis. KLF6 (Krüppel-like factor 6) is underexpressed in MM cells associated with bortezomib resistance. Knockdown of DJ-1 in these resistant cells restored sensitivity to bortezomib, concurrent with an increase in KLF6 levels (42). The KIAA1191 enzyme has been identified as an NADPH-dependent oxidoreductase involved in the production of ROS during oxidative reactions. Concurrently, receptor-interacting protein kinase 1 (RIP1), a core mediator of necroptosis, can promote the recruitment and activation of IκB kinase, thereby initiating the MAPK signaling cascade. Within this pathway, both MAPK1 and MAPK3 have also been reported to be activated by KIAA1191. These findings collectively suggest a potential mechanistic link between KIAA1191 and the necroptotic pathway. Overexpression of KIAA1191 reactivated the necroptotic signaling in MM cells, as evidenced by increased expression of RIP1, RIP3, and CYLD.

Furthermore, KIAA1191 overexpression synergized with bortezomib, significantly suppressing the proliferation of MM cells. These results imply that KIAA1191 may modulate necroptosis in MM and influence disease prognosis (43). The innate immune sensor ZBP1 (Z-DNA-binding protein 1) regulates cell proliferation in MM through its interaction with the IRF3 (interferon regulatory factor 3) signaling axis. ZBP1 is traditionally recognized for its role in detecting cytosolic DNA and initiating inflammatory responses. Understanding the role of the ZBP1-IRF3 axis in MM cell proliferation opens potential avenues for therapeutic intervention (44).

3 Necroptotic signaling in malignancy: friend, foe, or both?

Although necroptosis is widely regarded as an immunogenic and therapeutically exploitable form of regulated cell death, accumulating evidence indicates that its biological consequences in multiple myeloma are not uniformly beneficial. Instead, necroptotic signaling is tightly shaped by molecular checkpoints, cellular context, and microenvironmental cues, which collectively determine whether pathway activation results in tumor suppression or, paradoxically, supports disease progression. Accordingly, several key regulatory factors described above exhibit dual and opposing functions, emphasizing the need to consider necroptosis as a highly context-dependent process in MM (9, 22) (Table 3). Necroptotic tumor cells discharge a spectrum of DAMPs, including HMGB1, ATP, nucleic acids, and exposed ER/chaperone proteins, which act as “danger” signals for pattern PRRs on dendritic cells (DCs) and macrophages. Experimental models demonstrate that RIPK3/MLKL-dependent necroptosis enhances the release of extracellular ATP and HMGB1, and that deficiency in RIPK3 or MLKL diminishes the capacity of dying tumor cells to induce DC maturation and cross-presentation of tumor antigens to CD8⁺ T cells. These effects are central to the classification of necroptosis as an immunogenic cell death (ICD) modality (45). Lytic release of nuclear and mitochondrial DNA and RNA during necroptosis enables engagement of cytosolic nucleic acid sensors (e.g., cyclic GMP–AMP synthase (cGAS)–stimulator of interferon genes (STING) for DNA; RIG-I/MDA5 for RNA), with consequent induction of type I interferons (IFN-I) and interferon-stimulated genes. Type I IFNs produced in this context promote DC cross-priming, enhance antigen presentation, and recruit/activate effector lymphocytes. Recent preclinical work has established that necroptosis-dependent IFN signaling can be sufficient to generate protective antitumor immunity in murine models. However, as discussed below, sustained or dysregulated activation of these pathways can also promote immune suppression or exhaustion under certain conditions (46).

Table 3. Context-dependent factors influencing necroptosis outcomes in multiple myeloma.

The table summarizes molecular, cellular, and microenvironmental determinants that shift necroptosis toward anti-tumor (tumor cell death and immunogenicity) or pro-tumor (chronic inflammation and immune suppression) effects, including pathway activation intensity, cell type, post-translational regulation, genetic background, cytokine milieu, and therapeutic context, highlighting the need for biomarker-guided targeting of necroptosis in MM.

By promoting DC maturation and enhancing the cross-presentation of tumor antigens, necroptosis provides a potent stimulus for the priming of tumor-specific CD8⁺ T lymphocytes and the subsequent expansion of cytotoxic T-cell (CTL) effector responses. Activation of the RIPK3–MLKL axis results in membrane rupture and release of damage-associated molecular patterns (DAMPs), notably HMGB1, ATP, and nucleic acids, which engage pattern-recognition receptors on antigen-presenting cells, thereby driving costimulatory signaling and type I interferon production. Multiple transcriptomic and immunohistochemical studies have reported that elevated expression of core necroptosis regulators (RIPK3 and MLKL) or composite “necroptosis gene signatures” correlates with increased intratumorally CD8⁺ T-cell density and a T-cell-inflamed gene expression profile (20). In several tumor types, including melanoma, colorectal carcinoma, and hepatocellular carcinoma, such signatures are associated with favorable clinical outcomes and improved responsiveness to immune checkpoint blockade (ICB). These observations support the concept that therapeutically inducing necroptosis, through oncolytic viruses, radiotherapy, or pharmacologic RIPK3/MLKL activation, may convert otherwise immunologically “cold” tumors into “hot,” T-cell-inflamed lesions that are more amenable to ICB. Nonetheless, the context-dependent pro-inflammatory and potentially pro-tumorigenic consequences of sustained necroptosis warrant careful temporal and spatial control in clinical applications (47).

Necroptosis is recognized for its capacity to elicit robust anti-tumor immunity, and accumulating evidence indicates that the same pathway can drive a chronic inflammatory milieu that paradoxically promotes tumor progression. Persistent or spatially uncontrolled necroptotic activity sustains the release of damage-associated molecular patterns (DAMPs) and pro-inflammatory cytokines such as TNF-α, IL-6, and IL-1β. These mediators recruit and expand immunosuppressive myeloid populations, including myeloid-derived suppressor cells (MDSCs) and alternatively activated tumor-associated macrophages (TAMs), which inhibit cytotoxic T-cell responses and dampen antitumor immunity. In parallel, necroptosis-driven signaling can enhance angiogenesis through VEGF induction, promoting extracellular matrix remodeling and epithelial–mesenchymal transition, thereby facilitating local invasion and metastatic dissemination (48).

Both experimental models and integrative transcriptomic analyses highlight that the overall outcome of necroptosis, whether immunostimulatory or tumor-promoting, depends critically on the mechanistic context, including the magnitude and duration of RIPK3–MLKL activation, the cellular compartment in which necroptosis occurs (tumor cells versus stromal or immune cells), and the composition of the surrounding microenvironment. Consequently, therapeutic strategies aimed at harnessing necroptosis for cancer immunotherapy must incorporate precise temporal and spatial control, as well as biomarker-driven patient selection, to avoid tipping the balance toward chronic, tumor-supportive inflammation (48). Although necroptosis can initiate potent anti-tumor immune responses, the same pathway can drive a pro-tumorigenic inflammatory milieu when activation is excessive or poorly localized. Sustained or spatially diffuse necroptotic signaling results in the persistent release of damage-associated molecular patterns (DAMPs) and pro-inflammatory cytokines, including TNF-α, IL-6, and IL-1β. These mediators recruit and expand immunosuppressive myeloid populations, including myeloid-derived suppressor cells (MDSCs) and alternatively activated tumor-associated macrophages (TAMs), which collectively dampen cytotoxic T-cell activity and promote immune evasion (49).

Necroptosis-driven cytokine and growth factor signaling can potentiate angiogenesis, activate fibroblast-mediated extracellular matrix remodeling, and induce epithelial–mesenchymal transition, thereby facilitating local invasion and metastatic dissemination. Both experimental models and clinical transcriptomic analyses underscore that the immunologic outcome of necroptosis, whether antitumor or tumor-promoting, is highly context-dependent. Key determinants include the timing and magnitude of RIPK3–MLKL activation, the specific cellular compartment undergoing necroptosis (malignant, stromal, or immune), and the composition of the surrounding tumor microenvironment. Together, these factors determine whether necroptotic signaling leads to effective antitumor immunity or chronic inflammation that supports tumor progression (20, 48, 49).

As a summary, necroptosis is a context-dependent form of regulated cell death with dual potential to promote anti-tumor immunity or facilitate tumor progression. Activation of the RIPK3–MLKL axis induces the release of DAMPs, including HMGB1, ATP, and nucleic acids, enhancing dendritic cell maturation, tumor antigen presentation, and CD8⁺ T-cell priming. These effects can convert immunologically “cold” tumors into “hot” lesions, improving responsiveness to immunotherapy. Conversely, sustained or mislocalized necroptotic signaling can drive chronic inflammation, recruit immunosuppressive myeloid cells, and promote angiogenesis and metastasis. The net outcome depends on the magnitude, duration, and cellular context of necroptotic activation, as well as the tumor microenvironment. Therapeutic strategies that precisely control necroptosis, guided by biomarkers, offer a promising approach to enhance immunogenicity, overcome resistance, and improve clinical outcomes (50).

4 Conclusion

Therapeutic resistance in multiple myeloma remains a significant obstacle, mainly due to defects in apoptotic signaling. Necroptosis represents a promising alternative cell death pathway that can bypass resistance to apoptosis while enhancing tumor immunogenicity. Accumulating evidence links dysregulation of RIPK1, RIPK3, and MLKL to disease progression, treatment response, and patient prognosis, supporting their potential as both therapeutic targets and predictive biomarkers. Preclinical studies indicate that pharmacological activation of necroptosis can synergize with current anti-myeloma therapies, even within the protective bone marrow microenvironment. However, given the context-dependent immunological consequences of necroptosis, precise patient stratification and rational combination strategies will be essential. Targeting necroptotic pathways in a biomarker-guided manner may offer a viable strategy to overcome drug resistance and improve long-term outcomes in multiple myeloma.

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Footnotes

Edited by: Savita Rangarajan, University of Southampton, United Kingdom

Reviewed by: Venkatesh Pooladanda, Massachusetts General Hospital and Harvard Medical School, United States

Ruxandra Irimia, Emergency Hospital Prof. Dr. Agrippa Ionescu, Romania

Sreelakshmi Badavenkatappa Gari, Jawaharlal Nehru Technological University, India