The Landscape of lncRNAs in Multiple Myeloma: Implications in the “Hallmarks of Cancer”, Clinical Perspectives and Therapeutic Opportunities

Long non-coding RNAs (lncRNAs) are transcripts longer than 200 nucleotides that are not translated into proteins. Nowadays, lncRNAs are gaining importance as key regulators of gene expression and, consequently, of several biological functions in physiological and pathological conditions, including cancer. Here, we point out the role of lncRNAs in the pathogenesis of multiple myeloma (MM). We focus on their ability to regulate the biological processes identified as “hallmarks of cancer” that enable malignant cell transformation, early tumor onset and progression. The aberrant expression of lncRNAs in MM suggests their potential use as clinical biomarkers for diagnosis, patient stratification, and clinical management. Moreover, they represent ideal candidates for therapeutic targeting

Role of extracellular vesicle-based cell-to-cell communication in multiple myeloma progression

Multiple myeloma (MM) progression closely depends on the bidirectional crosstalk between tumor cells and the surrounding microenvironment, which leads to the creation of a tumor supportive niche. Extracellular vesicles (EVs) have emerged as key players in the pathological interplay between the malignant clone and near/distal bone marrow (BM) cells through their biologically active cargo. Here, we describe the role of EVs derived from MM and BM cells in reprogramming the tumor microenvironment and in fostering bone disease, angiogenesis, immunosuppression, drug resistance, and, ultimately, tumor progression. We also examine the emerging role of EVs as new therapeutic agents for the treatment of MM, and their potential use as clinical biomarkers for early diagnosis, disease classification, and therapy monitoring

Targeting angiogenesis in multiple myeloma by the VEGF and HGF blocking DARPin® protein MP0250: a preclinical study

The investigational drug MP0250 is a multi-specific DARPin® molecule that simultaneously binds and neutralizes VEGF and HGF with high specificity and affinity. Here we studied the antiangiogenic effects of the MP0250 in multiple myeloma (MM). In endothelial cells (EC) isolated from bone marrow (BM) of MM patients (MMEC) MP0250 reduces VEGFR2 and cMet phosphorylation and affects their downstream signaling cascades. MP0250 influences the secretory profile of MMEC and inhibits their in vitro angiogenic activities (spontaneous and chemotactic migration, adhesion, spreading and capillarogenesis). Compared to anti-VEGF or anti-HGF neutralizing mAbs, MP0250 strongly reduces capillary network formation and vessel-sprouting in a Matrigel angiogenesis assay. MP0250 potentiates the effect of bortezomib in the same in vitro setting. It significantly reduces the number of newly formed vessels in the choriollantoic membrane assay (CAM) and the Matrigel plug assay. In the syngeneic 5T33MM tumor model, MP0250 decreases the microvessel density (MVD) and the combination MP0250/bortezomib lowers the percentage of idiotype positive cells and the serum levels of M-protein. Overall results define MP0250 as a strong antiangiogenic agent with potential as a novel combination drug for treatment of MM patients

Inhibition of Notch-mediated crosstalk between endothelial cells and plasmacells reduces angiogenesis in multiple myeloma patients.

Inhibition of Notch-mediated crosstalk between endothelial cells and plasmacells reduces angiogenesis in multiple myeloma patient

Notch-Jag axis in the interplay between multiple myeloma and endothelium

Multiple myeloma(MM) is an incurable plasma cells malignancy. MM is characterized by aberrant activation of Notch signaling pathway due to Jag1 and 2 ligands overexpression. Notch activation occurs through homotypic interaction among MM cells and through heterotypic interaction of MM with surrounding bone marrow(BM) cells. In BM microenvironment, stromal cells support MM through Jag-Notch interaction and endothelial cells (ECs) are involved in MM progression and dissemination, indeed MM patients display high level of angiogenesis. The aim of this project is to study if MM cells influences BM-ECs behavior through Jag-mediated activation of Notch signaling. Jag1 and 2 were silenced in MM cell line using lentiviral vector (RPMI8226shJAG1/2) were cultured with human pulmonary aortic endothelial cells (HPAECs) used as model of ECs. Angiogenesis was assessed by Matrigel assay at 24 h. To assess the exclusive effect of Jag ligands on angiogenesis, HPAEC were directly stimulated with soluble Jag1. Wound healing assay was set up to assess variation in the migration ability of HPAEC using conditioned media from RPMI8226SCR and RPMI8226shJAG1/2 cells. Moreover, a 3D organoid was set up to mimic BM niche to study the interplay between MM cells and ECs. Matrigel assays indicate that an active Jag-Notch axis directed by MM cells stimulates angiogenesis. Indeed, the absence of Jag ligands in MM cells reduces their angiogenic potential. Moreover, Jag1 alone is sufficient to promote EC angiogenic capability. Also ECs motility is modulated through Notch signaling, more specifically CM from silenced MM cells have a reduced ability to activate cell motility suggesting that MM cells release Notch dependent soluble factors that stimulate migration. Assays with 3D organoids show that MM cells support ECs survival. These data suggest that the Jag-Notch axis is necessary for MM-associated angiogenesis

Autophagy: A New Mechanism of Prosurvival and Drug Resistance in Multiple Myeloma

Autophagy is an intracellular self-degradative process that balances cell energy source and regulates tissue homeostasis. In physiological condition, autophagy funnels cytoplasmic constituents to autophagolysosomes for degradation and is an alternative way for cell-death behavior. Here, we inspected autophagy as a prosurvival mechanism essential for drug resistance in multiple myeloma (MM). Accordingly, autophagy inhibitors used in association to conventional anti-MM drugs might enforce the effect against resistant MM plasma cells and render autophagy a new therapeutic target

Multiple myeloma associated angiogenesis: the notch pathway in the interplay between myeloma and endothelium

Multiple myeloma(MM) is a still incurable cancer that strongly depends on interactions with bone marrow(BM) microenvironment. Patients display high level of angiogenesis due to endothelial cells(ECs) malignant behavior as compared to healthy counterpart(1). Moreover, MM cells show dysregulation in Notch signaling pathway due to Jag ligands overexpression. This condition brings to the formation of a sustaining loop between MM cells with surrounding cells including bone marrow stromal cells(BMSCs) and osteoclasts. Although the role of Notch in MM progression, it is not clear its involvement in MM-EC crosstalk. Thus, this project aims to investigate this aspect of MM. Notch ligands, Jag1 and 2, were silenced in RPMI8226 cell line using short hairpin RNAs (RPMI8226shJAG1/2). For ECs, Human pulmonary aortic endothelial cells (HPAEC) was used and for BMSCs, the GFP+HS5 cell line. Matrigel and Wound Healing assays were set up to study Notch involvement in modulating angiogenesis potential of MM cells co-cultured with HPAEC and ECs motility in response to MM-produced soluble factors. To mimic MM niche, we generated an organoid exploiting a decellularized extracellular matrix as scaffold. We evaluated apoptosis of MM cells alone or in co-culture with BMSCs and with ECs by flow cytometry. Matrigel assay of HPAEC cultured with RPMI8226scrb cells showed that direct contact increased angiogenic potential of ECs; this effect was reduced in absence of Jag ligands, indicating an active role of Notch in ECs stimulation. Wound Healing assay demonstrates that the silencing of Notch signaling also influences HPAEC motility. Concerning the organoid, our results indicate that the dECM is suitable for cells seeding and 3D structure generation. Moreover, apoptosis assays show that MM cells display and increased survival in presence of BMSCs, confirming their protective role; we do not obtain significant difference in MM apoptosis in presence, or not, of ECs. Surprising, we observe that MM cells protect ECs suggesting that myeloma can improve angiogenesis also by preventing ECs apoptosis. These results indicate a novel and active role of Notch in MM-EC crosstalk; 3D organoid can mimic microenvironment and it can be used as novel tool to study BM microenvironment beyond animal models