INTRODUCTION:The CAN.HEAL consortium, comprising 47 cancer centers and academic institutions across 17 EU countries, has developed a set of recommendations for Molecular Tumor Boards (MTBs) to address the lack of standardized guidelines in personalized cancer medicine. METHODS:Over the past 2 years, through extensive collaboration and seven dedicated online meetings, CAN.HEAL experts developed consensus-based recommendations across 10 critical domains. RESULTS:The consortium agreed that MTBs' primary role is to perform molecular and clinical assessments for patients requiring care beyond standard treatment. Core MTB composition should include medical oncologists, molecular biologists, pathologists, and bioinformaticians. Patient eligibility criteria should prioritize performance status, with flexibility for rare cases. Shared informed consent is crucial for sample collection, data use, and research. A two-tiered IT workflow, with minimal and maximal datasets, is recommended, along with a comprehensive decision support tool. These recommendations focus on genomic testing, acknowledging diversity of NGS assays and proposing general guidelines. MTB reports should be concise, with technical details provided in the molecular diagnostic report. Innovative approaches like the Drug Rediscovery Protocol support access to off-label therapies. Harmonized training for MTB members is essential to bridging knowledge gaps in this evolving field. Indicators are needed to assess MTB effectiveness over time. Expanding MTB benefits to underserved populations depends on creating a shared European MTB database. CONCLUSION:Standardizing MTB practices represents a key step toward equitable access to personalized medicine and improved cancer care across Europe. Sustainable implementation requires coordinated EU efforts, and dynamic MTBs that continuously refine genomic-driven decisions within real-world contexts.

ABR-238901 treatment reduced IL-10 expression in MM cells in vivo.

PDF file - 116 KB, Combination index analysis of TH-302 combined with bortezomib at a non-constant ratio in MMS1 cells.

Supplementary data and figure legends

Primer sequences of genes evaluated by qRT-PCR.

ABR-238901 did not reduce viability of MDSC.

BACKGROUND: The aggressive B-cell non-Hodgkin lymphomas diffuse large B-cell lymphoma (DLBCL) and mantle cell lymphoma (MCL) are characterised by a high proliferation rate. The anaphase-promoting complex/cyclosome (APC/C) and its co-activators Cdc20 and Cdh1 represent an important checkpoint in mitosis. Here, the role of the APC/C and its co-activators is examined in DLBCL and MCL. METHODS: The expression and prognostic value of Cdc20 and Cdh1 was investigated using GEP data and immunohistochemistry. Moreover, the therapeutic potential of APC/C targeting was evaluated using the small-molecule inhibitor proTAME and the underlying mechanisms of action were investigated by western blot. RESULTS: We demonstrated that Cdc20 is highly expressed in DLBCL and aggressive MCL, correlating with a poor prognosis in DLBCL. ProTAME induced a prolonged metaphase, resulting in accumulation of the APC/C-Cdc20 substrate cyclin B1, inactivation/degradation of Bcl-2 and Bcl-xL and caspase-dependent apoptosis. In addition, proTAME strongly enhanced the anti-lymphoma effect of the clinically relevant agents doxorubicin and venetoclax. CONCLUSION: We identified for the first time APC/C as a new, promising target in DLBCL and MCL. Moreover, we provide evidence that Cdc20 might be a novel, independent prognostic factor in DLBCL and MCL.

Multiple Myeloma (MM) is an incurable malignancy of terminally differentiated plasma cells, which are predominantly localized in the bone marrow. Myeloid-derived suppressor cells (MDSC) are described to promote MM progression by immunosuppression and induction of angiogenesis. However, their direct role in drug resistance and tumor survival is still unknown. In this study, we performed co-culture experiments of myeloma cells with 5TMM derived MDSC in vitro, leading to increased survival and proliferation of MM cells. Co-culture experiments resulted in MDSC-induced AMPK phosphorylation in MM cells, which was associated with an increase in the anti-apoptotic factors MCL-1 and BCL-2, and the autophagy-marker LC3II. In addition, 5TMM cells inoculated in mice showed a clear upregulation of AMPK phosphorylation in vivo. Targeting the AMPK pathway by Compound C resulted in apoptosis of human myeloma cell lines, primary MM cells and 5TMM cells. Importantly, we observed that the tumor-promoting effect of MDSC was partially mediated by AMPK activation. In conclusion, our data clearly demonstrate that MDSC directly increase the survival of MM cells, partially through AMPK activation, identifying this pathway as a new target in the treatment of MM patients.

Despite current therapy improvements for mantle cell lymphoma (MCL) and diffuse large B cell lymphoma (DLBCL), most MCL patients and ± 40% of the DLBCL patients experience relapses. Both MCL and DLBCL are aggressive B cell lymphomas, characterized with a higher proliferation rate. The anaphase promoting complex/cyclosome (APC/C) is an important checkpoint in mitosis, regulating the onset of the anaphase and cell cycle. This E3 ubiquitin ligase becomes activated upon interaction with the co-factor CDC20. CDC20 is frequently overexpressed in different human cancers (prostate cancer, breast cancer, multiple myeloma, ...). This overexpression is associated with an aggressive course of the disease and a shorter overall survival. So far little is known about CDC20 in B cell lymphomas. Here, we investigated the inhibition of APC/C-CDC20 in MCL and DLBCL.

Abstract Dysregulated expression of S100 protein family members is associated with cancer proliferation, invasion, angiogenesis, and inflammation. S100A9 induces myeloid-derived suppressor cell (MDSC) accumulation and activity. MDSCs, immunosuppressive cells that contribute to tumor immune escape, are the main producers of S100A9. In this study, we evaluated the role of extracellular S100A9 and the therapeutic relevance of S100A9 inhibition in multiple myeloma (MM), using the immunocompetent murine 5T33MM model. We demonstrated the presence of S100A9 and its receptor TLR4 in both monocytic and granulocytic MDSCs in human and mouse samples. We showed that S100A9 acted as a chemoattractant for MM cells and induced MDSCs to express and secrete inflammatory and pro-myeloma cytokines, including TNFα, IL6, and IL10. Blocking S100A9 interactions in vivo with the small molecule ABR-238901 did not directly affect MDSC accumulation but did reduce IL6 and IL10 cytokine expression by MDSC. ABR-238901 treatment in vivo reduced angiogenesis but had only minor effects on tumor load as single agent (6% reduction). However, ABR-238901 treatment in combination with bortezomib resulted in an increased reduction in tumor load compared with single treatments (50% relative reduction compared with bortezomib alone). Our data suggest that extracellular S100A9 promotes MM and that inhibition of S100A9 may have therapeutic benefit. Cancer Immunol Res; 5(10); 839–46. ©2017 AACR.

Overcoming drug resistance is one of the greatest challenges in the treatment of multiple myeloma (MM). The interaction of myeloma cells with the bone marrow (BM) microenvironment is a major factor contributing to drug resistance. Tumour‐associated macrophages (TAMs) with different polarization states constitute an important component of this microenvironment. Previous studies have revealed a role of TAMs in MM cell survival and drug resistance; however, the impact of macrophage polarization (anti‐tumoural ‘M1’ versus pro‐tumoural ‘M2’‐like phenotype) in this process has not yet been described. Here, the presence of TAMs was confirmed in BM sections from MM patients, both at diagnosis and relapse, with two M2 markers, CD163 and CD206. By following different TAM subpopulations during disease progression in the syngeneic murine 5T33MM model, we demonstrated a decrease in the number of inflammatory monocytes and an increase in the number of M2‐oriented TAMs in BM. Co‐culture experiments demonstrated that macrophages provide a survival benefit to myeloma cells that is maintained after treatment with several classes of anti‐myeloma agent (melphalan and bortezomib); the greatest effect was observed with M2‐polarized macrophages. The pro‐survival effect was associated with activation of the STAT3 pathway in 5T33MM cells, less cleavage of caspase‐3, and thus less apoptosis. AZD1480, an ATP‐competitive JAK2 inhibitor, abrogated the observed TAM‐mediated MM cell survival, and partially inhibited resistance to bortezomib. Despite having only a small quantitative impact on myeloid cells in vivo, AZD1480 treatment alone and in combination with bortezomib significantly reduced tumour load. In conclusion, M2 TAMs are present in the MM microenvironment, and contribute to MM cell survival and protection from drug‐induced apoptosis. As a result of TAM‐induced activation of the STAT3 pathway, 5T33MM cells are sensitized to AZD1480 treatment. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

S100A9 belongs to a family of low-molecular-weight calcium-binding proteins and is involved in many biological processes including inflammation, cell migration and angiogenesis. It has been reported that S100A9 knockdown reduced myeloid-derived suppressor cell (MDSC) accumulation and Multiple Myeloma (MM) cell growth in MM models. MDSC are a heterogeneous population of immature myeloid cells and contribute to MM disease by immunosuppression, induction of angiogenesis and secretion of cytokines and growth factors. S100A9 is therefore proposed as an attractive drug target and compounds inhibiting the interaction of S100A9 with its receptors RAGE and TLR4 have been developed. In this study we evaluated the therapeutic relevance of S100A9 inhibition in MM using the preclinical immunocompetent murine 5T33MM model and two different small molecule inhibitors for S100A9 interactions (Active Biotech AB, Sweden). The presence of S100A9 was investigated in different cell populations. S100A9 is expressed in monocytic and granulocytic MDSC in murine and MM patient derived bone marrow (BM) samples, as demonstrated by western blot analysis and flow cytometry. S100A9 levels were higher in granulocytic MDSC compared to monocytic MDSC. Human MM cell lines and patient derived MM cells demonstrated low S100A9 expression, while no expression could be observed in 5T33MM cells. Treatment of 5T33MM mice with 30 mg/kg/day ABR-215757 (paquinimod) (quinoline-3-carboxamide analog) or ABR-238901 (N-(heteroaryl)-sulfonamide derivate) significantly diminished tumor cell percentages in the BM with ABR-238901 being the most potent one (27% relative reduction, p In conclusion, according to our study S100A9 is not involved in direct MDSC accumulation and activity; however it influences the expression of IL6 and IL10 by MDSC and act as a chemoattractant for MM cells. Interestingly, blocking S100A9 interactions in vivo affects angiogenesis and reduces tumor load especially in combination with bortezomib. Disclosures No relevant conflicts of interest to declare.

Multiple myeloma (MM) is a highly heterogeneous plasma cell malignancy. The MM cells reside in the bone marrow (BM), where reciprocal interactions with the BM niche foster MM cell survival, proliferation, and drug resistance. As in most cancers, the insulin-like growth factor (IGF) system has been demonstrated to play a key role in the pathogenesis of MM. The IGF system consists of IGF ligands, IGF receptors, IGF binding proteins (IGFBPs), and IGFBP proteases and contributes not only to the survival, proliferation, and homing of MM cells, but also MM-associated angiogenesis and osteolysis. Furthermore, increased IGF-I receptor (IGF-IR) expression on MM cells correlates with a poor prognosis in MM patients. Despite the prominent role of the IGF system in MM, strategies targeting the IGF-IR using blocking antibodies or small molecule inhibitors have failed to translate into the clinic. However, increasing preclinical evidence indicates that IGF-I is also involved in the development of drug resistance against current standard-of-care agents against MM, including proteasome inhibitors, immunomodulatory agents, and corticoids. IGF-IR targeting has been able to overcome or revert this drug resistance in animal models, enhancing the efficacy of standard-of-care agents. This finding has generated renewed interest in the therapeutic potential of IGF-I targeting in MM. The present review provides an update of the impact of the different IGF system components in MM and discusses the diagnostic and therapeutic potentials.

Multiple myeloma (MM) is a plasma cell malignancy characterized by the accumulation of tumor cells in the bone marrow (BM) and is associated with immunosuppression, angiogenesis and osteolysis. Myeloid-derived suppressor cells (MDSCs) represent a heterogeneous population of immature, immunosuppressive myeloid cells that promote tumor progression through different mechanisms.In this work, we studied the contribution of MDSC subsets to different disease-promoting aspects in MM. We observed an expansion of polymorphonuclear/granulocytic (PMN-)MDSCs in two immunocompetent murine MM models, while this was not observed for monocytic (MO-)MDSCs. Both MDSC subpopulations from MM-bearing mice were immunosuppressive, but PMN-MDSCs displayed a higher suppressive potential. Soluble factors secreted by MM cells increased the viability of MDSCs, whereas the presence of MDSCs did not affect the proliferation of MM cells in vitro or in vivo. Interestingly, we observed a pro-angiogenic effect of PMN-MDSCs in the context of MM using the chick chorioallantoic membrane assay. Consistently, MM-derived PMN-MDSCs showed an up-regulation of angiogenesis-related factors and reduced PMN-MDSC levels were associated with less angiogenesis in vivo. Finally, we identified MO-MDSCs as osteoclast precursors.These results suggest that MDSC subpopulations play diverging roles in MM. We show for the first time that PMN-MDSCs exert a pro-angiogenic role in MM.

Multiple myeloma (MM) is a hematological malignancy characterized by the accumulation of plasma cells in the bone marrow (BM). The success of the proteasome inhibitor bortezomib in the treatment of MM highlights the importance of the ubiquitin proteasome system (UPS) in this particular cancer. Despite the prolonged survival of MM patients, a significant amount of patients relapse or become resistant to therapy. This underlines the importance of the development and investigation of novel targets to improve MM therapy. The UPS plays an important role in different cellular processes by targeted destruction of proteins. The ubiquitination process consists of enzymes that transfer ubiquitin to proteins targeting them for proteasomal degradation. An emerging and promising approach is to target more disease specific components of the UPS to reduce side effects and overcome resistance. In this review, we will focus on different components of the UPS such as the ubiquitin activating enzyme E1, the ubiquitin conjugating enzyme E2, the E3 ubiquitin ligases, the deubiquitinating enzymes (DUBs) and the proteasome. We will discuss their role in MM and the implications in drug discovery for the treatment of MM.

The bone marrow (BM) represents a complex microenvironment containing stromal cells, immune cells, osteoclasts, osteoblasts, and hematopoietic cells, which are crucial for the immune response, bone formation, and hematopoiesis. Apart from soluble factors and direct cell-cell contact, extracellular vesicles (EVs), including exosomes, were recently identified as a third mediator for cell communication. Solid evidence has already demonstrated the involvement of various BM-derived cells and soluble factors in the regulation of multiple biological processes whereas the EV-mediated message delivery system from the BM has just been explored in recent decades. These EVs not only perform physiological functions but can also play a role in cancer development, including in Multiple Myeloma (MM) which is a plasma cell malignancy predominantly localized in the BM. This review will therefore focus on the multiple functions of EVs derived from BM cells, the manipulation of the BM by cancer-derived EVs, and the role of BM EVs in MM progression.

Mutual communication between multiple myeloma (MM) cells and mesenchymal stromal cells (MSC) plays a pivotal role in supporting MM progression. In MM, MSC exhibit a different genomic profile and dysregulated cytokine secretion compared to normal MSC, however the mechanisms involved in these changes are not fully understood. Here, we examined the miRNA changes in human MSC after culture with conditioned medium of MM cells and found 19 dysregulated miRNAs, including upregulated miR-146a. Moreover, exosomes derived from MM cells contained miR-146a and could be transferred into MSC. After overexpressing miR-146a in MSC, secretion of several cytokines and chemokines including CXCL1, IL6, IL-8, IP-10, MCP-1, and CCL-5 was elevated, resulting in the enhancement of MM cell viability and migration. DAPT, an inhibitor of the endogenous Notch pathway, was able to abrogate the miR-146a-induced increase of cytokines in MSC, suggesting the involvement of the Notch pathway. Taken together, our results demonstrate a positive feedback loop between MM cells and MSC: MM cells promote the increase of miR146a in MSC which leads to more cytokine secretion, which in turn favors MM cell growth and migration.

The anaphase promoting complex/cyclosome (APC/C) is an ubiquitin ligase involved in cell cycle. During the metaphase-anaphase transition the APC/C is activated by Cdc20. The aim of this study is to elucidate the importance and therapeutic potential of APC/C and its co-activator Cdc20 in multiple myeloma (MM). Gene expression analysis revealed that Cdc20 was expressed at higher levels in gene expression-based high-risk MM patients. Moreover, high Cdc20 expression correlated with poor prognosis. Treatment of human myeloma cell lines with proTAME, an APC/C inhibitor, resulted in an accumulation of APC/CCdc20 substrate cyclin B1 and an accumulation of cells in metaphase. Moreover we observed a significant dose-dependent decrease in viability and increase in apoptosis in MM cells upon proTAME treatment. The induction of apoptosis was accompanied with caspase 3, 8, 9 and PARP cleavage. A similar metaphase arrest and induction of apoptosis were obtained with specific knockdown of Cdc20. In addition, we demonstrated the accumulation of Bim was partially responsible for the observed cell death. Combining proTAME with another APC/C inhibitor apcin or the alkylating agent melphalan resulted in enhanced anti-MM activity. This study suggests that the APC/C and its co-activator Cdc20 could be a new and promising target especially in high-risk MM patients.