Smac-mimetics reduce numbers and viability of human osteoclasts

A Novel Necroptosis-Related Signature Can Predict Prognosis and Chemotherapy Sensitivity in Multiple Myeloma

BACKGROUND

Necroptosis is an inflammatory cell death mode, and its association with multiple myeloma (MM) remains unclear.

METHODS

This prospective study first analyzed the association between necroptosis-related signature as well as prognosis and chemotherapy sensitivity in MM using the necroptosis score. Consensus clustering was used to identify necroptosis-related molecular clusters. Least absolute shrinkage and selection operator analysis and multivariate Cox regression analysis were performed to establish the prognostic model of necroptosis-related genes (NRGs).

RESULTS

A high necroptosis score was associated with poor prognosis and abundant immune infiltration. Two molecular clusters (clusters A and B) significantly differed in terms of prognosis and tumor microenvironment. Cluster B had a worse prognosis and higher tumor marker pathway activity than cluster A. The risk score model based on four NRGs can accurately predict the prognosis of patients with MM, which was validated in two validation cohorts. Receiver operating characteristic curve analysis showed that the area under the curves of the risk score in predicting the 1-, 3-, and 5-year survival rates were 0.710, 0.758, and 0.834, respectively. Further, the activity of pathways related to proliferation and genetic regulation in the high-risk group significantly increased. The drug prediction results showed that the low-risk score group was more sensitive to bortezomib, cytarabine, and doxorubicin than the high-risk score group. Meanwhile, the high-risk score group was more sensitive to lenalidomide and vinblastine than the low-risk score group. Finally, the upregulation of model genes CHMP1A, FAS, JAK3, and HSP90AA1 in clinical samples collected from patients with MM was validated via real-time polymerase chain reaction.

CONCLUSION

A systematic analysis of NRGs can help identify potential necroptosis-related mechanisms and provide novel biomarkers for MM prognosis prediction, tumor microenvironment evaluation, and personalized treatment planning.

Transplantation of autologous bone marrow pre-loaded ex vivo with oncolytic myxoma virus is efficacious against drug-resistant Vk*MYC mouse myeloma

Multiple myeloma (MM) is a hematological malignancy of plasma cells that remains incurable despite significant progress with myeloablative regimens and autologous stem cell transplantation for eligible patients and, more recently with T cell redirected immunotherapy. Recently, we reported that ex vivo virotherapy with oncolytic myxoma virus (MYXV) improved MM-free survival in an autologous-transplant Balb/c mouse model. Here, we tested the Vk*MYC transplantable C57BL/6 mouse MM model that more closely recapitulates human disease. In vitro, the murine bortezomib-resistant Vk12598 cell line is fully susceptible to MYXV infection. In vivo results demonstrate: (i) autologous bone marrow (BM) leukocytes armed ex vivo with MYXV exhibit moderate therapeutic effects against MM cells pre-seeded into recipient mice; (ii) Cyclophosphamide in combination with BM/MYXV delays the onset of myeloma in mice seeded with Vk12598 cells; (iii) BM/MYXV synergizes with the Smac-mimetics LCL161 and with immune checkpoint inhibitor α-PD-1 to control the progression of established MM in vivo, resulting in significant improvement of survival rates and decreased of tumor burden; (iv) Survivor mice from (ii) and (iii), when re-challenged with fresh Vk12598 cells, developed acquired anti-MM immunity. These results highlight the utility of autologous BM grafts armed ex vivo with oncolytic MYXV alone or in combination with chemotherapy/immunotherapy to treat drug-resistant MM in vivo.

Cytoplasmic and Nuclear Functions of cIAP1

Cellular inhibitor of apoptosis 1 (cIAP1) is a cell signaling regulator of the IAP family. Through its E3-ubiquitine ligase activity, it has the ability to activate intracellular signaling pathways, modify signal transduction pathways by changing protein-protein interaction networks, and stop signal transduction by promoting the degradation of critical components of signaling pathways. Thus, cIAP1 appears to be a potent determinant of the response of cells, enabling their rapid adaptation to changing environmental conditions or intra- or extracellular stresses. It is expressed in almost all tissues, found in the cytoplasm, membrane and/or nucleus of cells. cIAP1 regulates innate immunity by controlling signaling pathways mediated by tumor necrosis factor receptor superfamily (TNFRs), some cytokine receptors and pattern recognition-receptors (PRRs). Although less documented, cIAP1 has also been involved in the regulation of cell migration and in the control of transcriptional programs.

Necroptosis: A new target for prevention of osteoporosis

Multiple causes may contribute to osteoporosis, characterized by a loss in bone mass and density as a consequence of the degradation of bone microstructure and a resultant rise in bone fragility. Recently, increasing attention has been paid to the role of necroptosis in the development of osteoporosis. Necroptosis is orchestrated by a set of proteins known as receptor-interacting protein kinase (RIPK)1, RIPK3, and mixed lineage kinase domain-like protein (MLKL). A necrosome is formed by MLKL, RIPK1, RIPK3, and RIPK3-RIPK3. A dissociated MLKL forms pores in the plasma membrane and eventually leads to necroptosis after translocating from the necrosome. In this review, we discuss a detailed understanding of necroptosis and its associated processes, a better understanding of its interactions with osteoclasts, osteoblasts, and osteocytes, and the associations between necroptosis and diabetic osteoporosis, steroid-induced osteoporosis, and postmenopausal osteoporosis. In addition, a variety of experimental medicines capable of modulating crucial necroptosis processes are highlighted. It's important to note that this is the first review paper to consolidate current data on the role of necroptosis in osteoporosis, and it offers fresh hope for the future treatment of this disease.

TAK1-inhibitors are cytotoxic for multiple myeloma cells alone and in combination with melphalan

Multiple myeloma (MM) is an incurable cancer caused by malignant transformation of plasma cells. Transforming growth factor-β activated kinase 1 (MAP3K7, TAK1) is a major regulator of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and mitogen-activated protein kinase (MAPK) signaling. Both NF-κB and MAPK control expression of genes with vital roles for drug resistance in MM. TAK1 is an attractive drug target as it switches these survival pathways to cell death. Our analysis showed that patients with high MAP3K7 expression in the tumor had shorter overall and progression free survival. The TAK1-inhibitors NG25 and 5Z-7-oxozeaenol (5Z-7) were cytotoxic to MM cell lines and patient cells. NG25 reduced expression of MYC and E2F controlled genes, involved in tumor cell growth, cell cycle progression and drug resilience. TAK1 can be activated by genotoxic stress. NG25 and 5Z-7 induced both synergistic and additive cytotoxicity in combination with the alkylating agent melphalan. Melphalan activated TAK1, NF-κB, and the MAPKs p38 and c-Jun N-terminal kinase (JNK), as well as a transcriptional UV-response. This was blocked by NG25, and instead apoptosis was activated. MM induce elevated bone-degradation resulting in myeloma bone disease (MBD), which is the main cause of disability and morbidity in MM patients. NG25 and 5Z-7 reduced differentiation and viability of human bone degrading osteoclasts, suggesting that TAK1-inhibition can have a double beneficial effect for patients. In sum, TAK1 is a promising drug target for MM treatment.