Natural killer cells activity against multiple myeloma cells is modulated by osteoblast-induced IL-6 and IL-10 production

Balancing the Scales: The Dual Role of Interleukins in Bone Metastatic Microenvironments

Bone metastases, a common and debilitating consequence of advanced cancers, involve a complex interplay between malignant cells and the bone microenvironment. Central to this interaction are interleukins (ILs), a group of cytokines with critical roles in immune modulation and inflammation. This review explores the dualistic nature of pro-inflammatory and anti-inflammatory interleukins in bone metastases, emphasizing their molecular mechanisms, pathological impacts, and therapeutic potential. Pro-inflammatory interleukins, such as IL-1, IL-6, and IL-8, have been identified as key drivers in promoting osteoclastogenesis, tumor proliferation, and angiogenesis. These cytokines create a favorable environment for cancer cell survival and bone degradation, contributing to the progression of metastatic lesions. Conversely, anti-inflammatory interleukins, including IL-4, IL-10, and IL-13, exhibit protective roles by modulating immune responses and inhibiting osteoclast activity. Understanding these opposing effects is crucial for developing targeted therapies aimed at disrupting the pathological processes in bone metastases. Key signaling pathways, including NF-κB, JAK/STAT, and MAPK, mediate the actions of these interleukins, influencing tumor cell survival, immune cell recruitment, and bone remodeling. Targeting these pathways presents promising therapeutic avenues. Current treatment strategies, such as the use of denosumab, tocilizumab, and emerging agents like bimekizumab and ANV419, highlight the potential of interleukin-targeted therapies in mitigating bone metastases. However, challenges such as therapeutic resistance, side effects, and long-term efficacy remain significant hurdles. This review also addresses the potential of interleukins as diagnostic and prognostic biomarkers, offering insights into patient stratification and personalized treatment approaches. Interleukins have multifaceted roles that depend on the context, including the environment, cell types, and cellular interactions. Despite substantial progress, gaps in research persist, particularly regarding the precise mechanisms by which interleukins influence the bone metastatic niche and their broader clinical implications. While not exhaustive, this overview underscores the critical roles of interleukins in bone metastases and highlights the need for continued research to fully elucidate their complex interactions and therapeutic potential. Addressing these gaps will be essential for advancing our understanding and treatment of bone metastases in cancer patients.

Natural killer cells affect the natural course, drug resistance, and prognosis of multiple myeloma

Multiple myeloma (MM), a stage-developed plasma cell malignancy, evolves from monoclonal gammopathy of undetermined significance (MGUS) or smoldering MM (SMM). Emerging therapies including immunomodulatory drugs, proteasome inhibitors, monoclonal antibodies, chimeric antigen-T/natural killer (NK) cells, bispecific T-cell engagers, selective inhibitors of nuclear export, and small-molecule targeted therapy have considerably improved patient survival. However, MM remains incurable owing to inevitable drug resistance and post-relapse rapid progression. NK cells with germline-encoded receptors are involved in the natural evolution of MGUS/SMM to active MM. NK cells actively recognize aberrant plasma cells undergoing malignant transformation but are yet to proliferate during the elimination phase, a process that has not been revealed in the immune editing theory. They are potential effector cells that have been neglected in the therapeutic process. Herein, we characterized changes in NK cells regarding disease evolution and elucidated its role in the early clinical monitoring of MM. Additionally, we systematically explored dynamic changes in NK cells from treated patients who are in remission or relapse to explore future combination therapy strategies to overcome drug resistance.

GSK-3β/β-catenin pathway plays crucial roles in the regulation of NK cell cytotoxicity against myeloma cells

The plasma cell malignancy, multiple myeloma (MM), has significantly improved by the application of new drugs and autologous hematopoietic stem cell transplantation. However, MM remains incurable. A number of studies have revealed an anti-MM effect of natural killer (NK) cells; however, their clinical efficacy is limited. Furthermore, glycogen synthase kinase (GSK)-3β inhibitors show an antitumor function. In this study, we aimed to evaluate the potential roles of a GSK-3β inhibitor (TWS119) in the regulation of NK cell cytotoxicity against MM. Our results showed that, in the presence of TWS119, the NK cell line, NK-92, and in vitro-expanded primary NK cells exhibited a significantly higher degranulation activity, expression of activating receptors, cellular cytotoxicity, and cytokine secretion when they were exposed to MM cells. Mechanistic studies indicated that TWS119 treatment markedly upregulated RAB27A expression, a key molecule for NK cell degranulation, and induced the colocalization of β-catenin with NF-κB in the nucleus of NK cells. More importantly, GSK-3β inhibition combined with the adoptive transfer of TWS119-treated NK-92 cells significantly reduced tumor volume and prolonged the survival time of myeloma-bearing mice. In summary, our novel findings suggest that targeting GSK-3β through the activation of β-catenin/NF-κB pathway may be an important approach to improve therapeutic efficacy of NK cell transfusion for MM.