Homotypic and Heterotypic Activation of the Notch Pathway in Multiple Myeloma-Enhanced Angiogenesis: A Novel Therapeutic Target?

In vitro antineoplastic effects of MK0752 in HPV-positive head and neck squamous cell carcinoma

PURPOSE

Gamma-secretase inhibitor MK0752 has shown a high therapeutic potential in different solid malignant tumors. Up to now, its antineoplastic effects were not investigated in head and neck squamous cell carcinoma (HNSCC) and particularly in human-papillomavirus (HPV)-positive tumors.

METHODS

We conducted cytotoxic, migration, and clonogenic assays in two HPV-negative HNSCC cell lines (Cal27 and FaDu) and one HPV-positive cell line (SCC154). Furthermore, in order to assess the pro-apoptotic effects of MK0752, a Caspase 3/7 Glo assay was performed.

RESULTS

Our experiments revealed antineoplastic effects of MK0752 in all three cell lines. Strong cytotoxic and antimigratory potential was shown in all cell lines, with strongest effects observed in the HPV-positive cell line. Meanwhile, anticlonogenic effects were only shown in Cal27 and SCC154. Most importantly, MK0752 induced apoptosis solely in HPV-positive SCC154.

CONCLUSIONS

Our novel findings indicate a therapeutic potential of MK0752 in HPV-positive HNSCC. Indeed, further investigation is needed for validation of our results and for the assessment of the mechanistic background.

The Potential of JAG Ligands as Therapeutic Targets and Predictive Biomarkers in Multiple Myeloma

The NOTCH ligands JAG1 and JAG2 have been correlated in vitro with multiple myeloma (MM) cell proliferation, drug resistance, self-renewal and a pathological crosstalk with the tumor microenvironment resulting in angiogenesis and osteoclastogenesis. These findings suggest that a therapeutic approach targeting JAG ligands might be helpful for the care of MM patients and lead us to explore the role of JAG1 and JAG2 in a MM in vivo model and primary patient samples. JAG1 and JAG2 protein expression represents a common feature in MM cell lines; therefore, we assessed their function through JAG1/2 conditional silencing in a MM xenograft model. We observed that JAG1 and JAG2 showed potential as therapeutic targets in MM, as their silencing resulted in a reduction in the tumor burden. Moreover, JAG1 and JAG2 protein expression in MM patients was positively correlated with the presence of MM cells in patients' bone marrow biopsies. Finally, taking advantage of the Multiple Myeloma Research Foundation (MMRF) CoMMpass global dataset, we showed that JAG2 gene expression level was a predictive biomarker associated with patients' overall survival and progression-free survival, independently from other main molecular or clinical features. Overall, these results strengthened the rationale for the development of a JAG1/2-tailored approach and the use of JAG2 as a predictive biomarker in MM.

Anti-Angiogenic Activity of Drugs in Multiple Myeloma

Angiogenesis represents a pivotal hallmark of multiple myeloma (MM) that correlates to patients’ prognosis, overall survival, and drug resistance. Hence, several anti-angiogenic drugs that directly target angiogenic cytokines (i.e., monoclonal antibodies, recombinant molecules) or their cognate receptors (i.e., tyrosine kinase inhibitors) have been developed. Additionally, many standard antimyeloma drugs currently used in clinical practice (i.e., immunomodulatory drugs, bisphosphonates, proteasome inhibitors, alkylating agents, glucocorticoids) show anti-angiogenic effects further supporting the importance of inhibiting angiogenesis from potentiating the antimyeloma activity. Here, we review the most important anti-angiogenic therapies used for the management of MM patients with a particular focus on their pharmacological profile and on their anti-angiogenic effect in vitro and in vivo. Despite the promising perspective, the direct targeting of angiogenic cytokines/receptors did not show a great efficacy in MM patients, suggesting the need to a deeper knowledge of the BM angiogenic niche for the design of novel multi-targeting anti-angiogenic therapies.

NEPHROPROTECTIVE EFFECT OF GAMMA-SECRETASE INHIBITOR ON SEPSIS- INDUCED RENAL INJURY IN MOUSE MODEL OF CLP

OBJECTIVE

The aim: This study was set out to assess the potential protective impact of MK0752 (a gamma secretase inhibitor) on sepsis-induced renal injury through modulation of inflammatory and oxidative stress pathways.

PATIENTS AND METHODS

Materials and methods: Twenty-four Swiss-albino mice aged between eight and twelve week and weighted twenty to thirty-seven grams were randomly allocated into four groups (n=6 in each group). Sham group (laparotomy without cecal ligation and puncture (CLP), sepsis group (laparotomy with CLP), vehicle-treated group (equivalent volume of DMSO before the CLP), MK0752 treated group (5 mg/kg) single daily dose for three days before the CLP. Blood samples were used to assess the serum levels of urea and creatinine. The kidneys were used to assess tissue levels of the TNF-α, IL-10, IL-6, TNFR1, VEGF, notch1, jagged1 and tissue damage by histopathological analysis.

RESULTS

Results: The current study shows that pretreatment with MK0752 ameliorates the renal damage by significantly reducing the proinflammatory cytokines and notch1 signaling.

CONCLUSION

Conclusions: Taken together, these results suggest that MK0752 could be protective against the renal injury induced by sepsis through its ameliorative impact on renal architecture and modulating cytokines and Notch1 singling pathway. Further studies regarding the role of Notch signaling pathways would be worthwhile.

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

Simple Summary

Multiple myeloma (MM) is an aggressive hematological neoplasia caused by the uncontrolled proliferation of aberrant plasmacells. Neoplastic transformation and progression are driven by a number of biological processes, called ‘hallmarks of cancer’, which are regulated by different molecules, including long non-coding RNAs. A deeper understanding of the mechanisms that regulate MM development and progression will help to improve patients stratification and management, and promote the identification of new therapeutic targets.

Abstract

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.

Altered pathways and targeted therapy in double hit lymphoma

High-grade B-cell lymphoma with translocations involving MYC and BCL2 or BCL6, usually referred to as double hit lymphoma (DHL), is an aggressive hematological malignance with distinct genetic features and poor clinical prognosis. Current standard chemoimmunotherapy fails to confer satisfying outcomes and few targeted therapeutics are available for the treatment against DHL. Recently, the delineating of the genetic landscape in tumors has provided insight into both biology and targeted therapies. Therefore, it is essential to understand the altered signaling pathways of DHL to develop treatment strategies with better clinical benefits. Herein, we summarized the genetic alterations in the two DHL subtypes (DHL-BCL2 and DHL-BCL6). We further elucidate their implications on cellular processes, including anti-apoptosis, epigenetic regulations, B-cell receptor signaling, and immune escape. Ongoing and potential therapeutic strategies and targeted drugs steered by these alterations were reviewed accordingly. Based on these findings, we also discuss the therapeutic vulnerabilities that coincide with these genetic changes. We believe that the understanding of the DHL studies will provide insight into this disease and capacitate the finding of more effective treatment strategies.

A Novel Model of Tumor-Infiltrating B Lymphocyte Specific RNA-Binding Protein-Related Genes With Potential Prognostic Value and Therapeutic Targets in Multiple Myeloma

Background: RNA-binding proteins (RBPs) act as important regulators in the progression of tumors. However, their role in the tumorigenesis and prognostic assessment in multiple myeloma (MM), a B-cell hematological cancer, remains elusive. Thus, the current study was designed to explore a novel prognostic B-cell-specific RBP signature and the underlying molecular mechanisms.

Methods: Data used in the current study were obtained from the Gene Expression Omnibus (GEO) database. Significantly upregulated RBPs in B cells were defined as B cell-specific RBPs. The biological functions of B-cell-specific RBPs were analyzed by the cluster Profiler package. Univariate and multivariate regressions were performed to identify robust prognostic B-cell specific RBP signatures, followed by the construction of the risk classification model. Gene set enrichment analysis (GSEA)-identified pathways were enriched in stratified groups. The microenvironment of the low- and high-risk groups was analyzed by single-sample GSEA (ssGSEA). Moreover, the correlations among the risk score and differentially expressed immune checkpoints or differentially distributed immune cells were calculated. The drug sensitivity of the low- and high-risk groups was assessed via Genomics of Drug Sensitivity in Cancer by the pRRophetic algorithm. In addition, we utilized a GEO dataset involving patients with MM receiving bortezomib therapy to estimate the treatment response between different groups.

Results: A total of 56 B-cell-specific RBPs were identified, which were mainly enriched in ribonucleoprotein complex biogenesis and the ribosome pathway. ADAR, FASTKD1 and SNRPD3 were identified as prognostic B-cell specific RBP signatures in MM. The risk model was constructed based on ADAR, FASTKD1 and SNRPD3. Receiver operating characteristic (ROC) curves revealed the good predictive capacity of the risk model. A nomogram based on the risk score and other independent prognostic factors exhibited excellent performance in predicting the overall survival of MM patients. GSEA showed enrichment of the Notch signaling pathway and mRNA cis-splicing via spliceosomes in the high-risk group. Moreover, we found that the infiltration of diverse immune cell subtypes and the expression of CD274, CD276, CTLA4 and VTCN1 were significantly different between the two groups. In addition, the IC50 values of 11 drugs were higher in the low-risk group. Patients in the low-risk group exhibited a higher complete response rate to bortezomib therapy.

Conclusion: Our study identified novel prognostic B-cell-specific RBP biomarkers in MM and constructed a unique risk model for predicting MM outcomes. Moreover, we explored the immune-related mechanisms of B cell-specific RBPs in regulating MM. Our findings could pave the way for developing novel therapeutic strategies to improve the prognosis of MM patients.

[18F](2S,4R)-4-Fluoroglutamine as a New Positron Emission Tomography Tracer in Myeloma

The high glycolytic activity of multiple myeloma (MM) cells is the rationale for use of Positron Emission Tomography (PET) with ¹⁸F-fluorodeoxyglucose ([¹⁸F]FDG) to detect both bone marrow (BM) and extramedullary disease. However, new tracers are actively searched because [¹⁸F]FDG-PET has some limitations and there is a portion of MM patients who are negative. Glutamine (Gln) addiction has been recently described as a typical metabolic feature of MM cells. Yet, the possible exploitation of Gln as a PET tracer in MM has never been assessed so far and is investigated in this study in preclinical models. Firstly, we have synthesized enantiopure (2S,4R)-4-fluoroglutamine (4-FGln) and validated it as a Gln transport analogue in human MM cell lines, comparing its uptake with that of ³H-labelled Gln. We then radiosynthesized [¹⁸F]4-FGln, tested its uptake in two different in vivo murine MM models, and checked the effect of Bortezomib, a proteasome inhibitor currently used in the treatment of MM. Both [¹⁸F]4-FGln and [¹⁸F]FDG clearly identified the spleen as site of MM cell colonization in C57BL/6 mice, challenged with syngeneic Vk12598 cells and assessed by PET. NOD.SCID mice, subcutaneously injected with human MM JJN3 cells, showed high values of both [¹⁸F]4-FGln and [¹⁸F]FDG uptake. Bortezomib significantly reduced the uptake of both radiopharmaceuticals in comparison with vehicle at post treatment PET. However, a reduction of glutaminolytic, but not of glycolytic, tumor volume was evident in mice showing the highest response to Bortezomib. Our data indicate that [¹⁸F](2S,4R)-4-FGln is a new PET tracer in preclinical MM models, yielding a rationale to design studies in MM patients.

A mechanistic review of the anticancer potential of hesperidin, a natural flavonoid from citrus fruits

Hesperidin, a phytoactive compound, is an abundant and economical dietary bioflavonoid possessing numerous biological and medicinal benefits. Several studies have strongly proven the significant chemotherapeutic potential of hesperidin. Therefore, this review aims to bring together the existing studies demonstrating hesperidin as a potential anticancer agent with its mode of action reported in the therapeutic strategies for numerous cancer types. Hesperidin acts via modulating multiple pathways involving cell cycle arrest, apoptosis, antiangiogenic, antimetastatic and DNA repair in various cancer cells. Hesperidin has been reported to alter several molecular targets related to carcinogenesis, such as reactive nitrogen species, cellular kinases, transcription factors, reactive oxygen species, drug transporters, cell cycle mediators and inflammatory cytokines. Collectively, this review provides significant insights for the potential of hesperidin to be a strong and promising candidate for pharmaceuticals, functional foods, dietary supplements, nutraceuticals and geared toward the better management of carcinoma.

Targeting Notch Pathway in Cancer Diagnostics and Therapeutics: An Emerging Approach

The Notch signaling pathway is an evolutionarily conserved pathway usually present in multicellular organisms, which plays a pivotal role in cell fate determination and proliferation. Due to this property, it is highly oncogenic, especially in the dysregulated version of the Notch pathway, where apoptosis is inhibited, and abnormal cell growth is supported. Notch receptors and ligand proteins play an essential role in cancers, for instance, myeloid leukemia, T-cell lymphoblastic leukemia, and organ-specific, i.e., breast, colon, pancreas, and skin cancers. Any type of cancer generates as a result of genetic defects, including epigenetic alterations as well as mutations. These alterations can be used by the researchers to find a promising diagnostic as well as therapeutic tool for cancer. The successful inhibition of the Notch pathway with the help of specific biomarkers or suppression of gene expression represents a new remedy in the field of cancer research. This article focuses on the various remedies hidden within the Notch pathway's mechanism, primarily based on different patents published in recent years for assisting cancer diagnosis and succeeding treatment.

The multifunctional role of Notch signaling in multiple myeloma

Multiple myeloma (MM) is a hematologic cancer characterized by uncontrolled growth of malignant plasma cells in the bone marrow and currently is incurable. The bone marrow microenvironment plays a critical role in MM. MM cells reside in specialized niches where they interact with multiple marrow cell types, transforming the bone/bone marrow compartment into an ideal microenvironment for the migration, proliferation, and survival of MM cells. In addition, MM cells interact with bone cells to stimulate bone destruction and promote the development of bone lesions that rarely heal. In this review, we discuss how Notch signals facilitate the communication between adjacent MM cells and between MM cells and bone/bone marrow cells and shape the microenvironment to favor MM progression and bone disease. We also address the potential and therapeutic approaches used to target Notch signaling in MM.

Morphogens and growth factor signalling in the myeloma bone-lining niche

Multiple myeloma is a malignancy caused by the clonal expansion of abnormal plasma cells. Myeloma cells have proven to be incredibly successful at manipulating their microenvironment to promote growth and to evade modern therapies. They have evolved to utilise the integral signalling pathways of the bone and bone marrow to drive disease progression. The bone marrow is often described in the context of a single structure that fills the bone cavity and supports normal haematopoiesis. However, within that structure exists two anatomically different niches, the perivascular niche and the endosteal niche. These contain different cell types functioning to support normal immune and blood cell production as well as healthy bone. These cells secrete numerous signalling molecules that can influence myeloma cell biology and behaviour. The endosteal niche is home to specific bone cell lineages and plays a pivotal role in myeloma cell establishment and survival. This review will concentrate on some of the signalling pathways that are hijacked by myeloma cells to shape a favourable environment, and the different influences myeloma cells are exposed to depending on their spatial location within the bone marrow.

The immune contexture of primary central nervous system diffuse large B cell lymphoma associates with patient survival and specific cell signaling

Rationale: Primary central nervous system diffuse large B-cell lymphoma (PCNSL) is a rare and aggressive entity that resides in an immune-privileged site. The tumor microenvironment (TME) and the disruption of the immune surveillance influence lymphoma pathogenesis and immunotherapy resistance. Despite growing knowledge on heterogeneous therapeutic responses, no comprehensive description of the PCNSL TME is available. We hence investigated the immune subtypes of PCNSL and their association with molecular signaling and survival. Methods: Analysis of PCNSL transcriptomes (sequencing, n = 20; microarrays, n = 34). Integrated correlation analysis and signaling pathway topology enabled us to infer intercellular interactions. Immunohistopathology and digital imaging were used to validate bioinformatic results. Results: Transcriptomics revealed three immune subtypes: immune-rich, poor, and intermediate. The immune-rich subtype was associated to better survival and characterized by hyper-activation of STAT3 signaling and inflammatory signaling, e.g., IFNγ and TNF-α, resembling the hot subtype described in primary testicular lymphoma and solid cancer. WNT/β-catenin, HIPPO, and NOTCH signaling were hyper-activated in the immune-poor subtype. HLA down-modulation was clearly associated with a low or intermediate immune infiltration and the absence of T-cell activation. Moreover, HLA class I down-regulation was also correlated with worse survival with implications on immune-intermediate PCNSL that frequently feature reduced HLA expression. A ligand-receptor intercellular network revealed high expression of two immune checkpoints, i.e., CTLA-4/CD86 and TIM-3/LAGLS9. TIM-3 and galectin-9 proteins were clearly upregulated in PCNSL. Conclusion: Altogether, our study reveals that patient stratification according to immune subtypes, HLA status, and immune checkpoint molecule quantification should be considered prior to immune checkpoint inhibitor therapy. Moreover, TIM-3 protein should be considered an axis for future therapeutic development.

Osteocyte Vegf-a contributes to myeloma-associated angiogenesis and is regulated by Fgf23

Multiple Myeloma (MM) induces bone destruction, decreases bone formation, and increases marrow angiogenesis in patients. We reported that osteocytes (Ocys) directly interact with MM cells to increase tumor growth and expression of Ocy-derived factors that promote bone resorption and suppress bone formation. However, the contribution of Ocys to enhanced marrow vascularization in MM is unclear. Since the MM microenvironment is hypoxic, we assessed if hypoxia and/or interactions with MM cells increases pro-angiogenic signaling in Ocys. Hypoxia and/or co-culture with MM cells significantly increased Vegf-a expression in MLOA5-Ocys, and conditioned media (CM) from MLOA5s or MM-MLOA5 co-cultured in hypoxia, significantly increased endothelial tube length compared to normoxic CM. Further, Vegf-a knockdown in MLOA5s or primary Ocys co-cultured with MM cells or neutralizing Vegf-a in MM-Ocy co-culture CM completely blocked the increased endothelial activity. Importantly, Vegf-a-expressing Ocy numbers were significantly increased in MM-injected mouse bones, positively correlating with tumor vessel area. Finally, we demonstrate that direct contact with MM cells increases Ocy Fgf23, which enhanced Vegf-a expression in Ocys. Fgf23 deletion in Ocys blocked these changes. These results suggest hypoxia and MM cells induce a pro-angiogenic phenotype in Ocys via Fgf23 and Vegf-a signaling, which can promote MM-induced marrow vascularization.

Jagged Ligands Enhance the Pro-Angiogenic Activity of Multiple Myeloma Cells

Simple Summary

The Jagged family of ligands are aberrantly expressed during multiple myeloma progression and contributes to activate Notch signaling both in myeloma cells and in the nearby bone marrow cell populations activating several pro-tumor effects. This work elucidates, in vitro, in vivo as well as in patients’ bone marrow biopsies, different mechanisms by which tumor cell-derived Jagged1 and 2 contribute to myeloma-associated angiogenesis. These include the ability to induce myeloma and bone marrow stromal cell secretion of VEGF along with a direct activation of the pro-angiogenic Notch signaling pathway in endothelial cells. This research provides a rational for a Jagged-directed therapy in multiple myeloma.

Abstract

Multiple myeloma (MM) is an incurable plasma cell malignancy arising primarily within the bone marrow (BM). During MM progression, different modifications occur in the tumor cells and BM microenvironment, including the angiogenic shift characterized by the increased capability of endothelial cells to organize a network, migrate and express angiogenic factors, including vascular endothelial growth factor (VEGF). Here, we studied the functional outcome of the dysregulation of Notch ligands, Jagged1 and Jagged2, occurring during disease progression, on the angiogenic potential of MM cells and BM stromal cells (BMSCs). Jagged1–2 expression was modulated by RNA interference or soluble peptide administration, and the effects on the MM cell lines’ ability to induce human pulmonary artery cells (HPAECs) angiogenesis or to indirectly increase the BMSC angiogenic potential was analyzed in vitro; in vivo validation was performed on a zebrafish model and MM patients’ BM biopsies. Overall, our results indicate that the MM-derived Jagged ligands (1) increase the tumor cell angiogenic potential by directly triggering Notch activation in the HPAECs or stimulating the release of angiogenic factors, i.e., VEGF; and (2) stimulate the BMSCs to promote angiogenesis through VEGF secretion. The observed pro-angiogenic effect of Notch activation in the BM during MM progression provides further evidence of the potential of a therapy targeting the Jagged ligands.

MiR-375-3p regulates rat pulmonary microvascular endothelial cell activity by targeting Notch1 during hypoxia

Objective

Pulmonary microvascular endothelial cells (PMECs) exhibit specific responses in adaptation to hypoxia. However, the mechanisms regulating PMEC activities during hypoxia remain unclear. This study investigated the potential involvement of a microRNA, miR-375-3p, in the regulation of PMEC activities.

Methods

Primary PMECs were isolated from rats. The expression levels of miR-375-3p and Notch1 in the PMECs were detected by quantitative PCR and western blotting. Luciferase reporter assays were performed to explore the transcriptional regulation of Notch1 by miR-375-3p. The proliferation and chemotaxis of the PMECs were measured with the Cell Counting Kit-8 and Transwell invasion assays, respectively. Additionally, the capacity of hypoxia-treated PMECs for angiogenesis and inflammatory response was determined with tube formation assays and ELISA, respectively.

Results

The expression of miR-375-3p and Notch1 in the PMECs was significantly down-regulated and up-regulated during hypoxia, respectively. The results demonstrated that miR-375-3p directly targets Notch1 in PMECs, thereby suppressing the transcriptional expression of Notch1. It was further revealed that miR-375-3p regulates the proliferation, chemotaxis, angiogenesis, and inflammatory response of PMECs.

Conclusions

Our findings revealed the important role of miR-375-3p in the regulation of PMEC function and suggest the potential involvement of miR-375-3p in the development of lung diseases.

Endothelial Progenitors in the Tumor Microenvironment

Tumor vascularization refers to the formation of new blood vessels within a tumor and is considered one of the hallmarks of cancer. Tumor vessels supply the tumor with oxygen and nutrients, required to sustain tumor growth and progression, and provide a gateway for tumor metastasis through the blood or lymphatic vasculature. Blood vessels display an angiocrine capacity of supporting the survival and proliferation of tumor cells through the production of growth factors and cytokines. Although tumor vasculature plays an essential role in sustaining tumor growth, it represents at the same time an essential way to deliver drugs and immune cells to the tumor. However, tumor vasculature exhibits many morphological and functional abnormalities, thus resulting in the formation of hypoxic areas within tumors, believed to represent a mechanism to maintain tumor cells in an invasive state.Tumors are vascularized through a variety of modalities, mainly represented by angiogenesis, where VEGF and other members of the VEGF family play a key role. This has represented the basis for the development of anti-VEGF blocking agents and their use in cancer therapy: however, these agents failed to induce significant therapeutic effects.Much less is known about the cellular origin of vessel network in tumors. Various cell types may contribute to tumor vasculature in different tumors or in the same tumor, such as mature endothelial cells, endothelial progenitor cells (EPCs), or the same tumor cells through a process of transdifferentiation. Early studies have suggested a role for bone marrow-derived EPCs; these cells do not are true EPCs but myeloid progenitors differentiating into monocytic cells, exerting a proangiogenic effect through a paracrine mechanism. More recent studies have shown the existence of tissue-resident endothelial vascular progenitors (EVPs) present at the level of vessel endothelium and their possible involvement as cells of origin of tumor vasculature.

Notch receptors and ligands in inflammatory arthritis - a systematic review

BACKGROUND

Notch pathway is highly conserved across species and is involved in the regulation of cell differentiation and activity both in embryonic development and adult life. Notch signaling has an important role in the development of hematopoietic stem cells and their differentiation to committed lineages, as well as in the regulation of several non-hematopoietic cell lines.

OBJECTIVE

As Notch signaling has been implicated in various inflammatory and autoimmune diseases, it is of interest to elucidate what role do Notch receptors and ligands have in inflammatory arthritides.

METHODS

We performed a search on the role of Notch receptors (1-4) and Notch ligands Delta-like (DLL) 1, 3, 4 and Jagged (Jag) 1 and 2 in animal models of inflammatory arthritis and most common types of human inflammatory arthritis (rheumatoid arthritis, psoriatic arthritis or ankylosing spondylitis). The initial search identified 135 unique articles, of which 24 were ultimately deemed relevant and included in this systematic review.

RESULTS

Overall, identified articles describe roles for Notch ligands and receptors in inflammatory arthritis, with Notch activation resulting in enhanced Th1/17 polarization, osteoclast differentiation, macrophage activation and fibroblast-like synoviocyte proliferation. However, the inhibitory role of Notch signaling, especially by Jag1 is also described.

CONCLUSION

There is evidence that Notch pathway activation affects multiple cell lineages present within the arthritic environment, therefore potentially acting as one of the drivers of disease pathogenesis. Since cell lineage-selective transgenic mouse models and specific Notch receptor inhibitors are becoming increasingly available, it can be expected that future research will evaluate whether Notch signaling components initiate crucial pathogenic impulses and, therefore, present viable therapeutic targets in inflammatory arthritis.

Mechanisms of Resistance to Anti-CD38 Daratumumab in Multiple Myeloma

Daratumumab (Dara) is the first-in-class human-specific anti-CD38 mAb approved for the treatment of multiple myeloma (MM). Although recent data have demonstrated very promising results in clinical practice and trials, some patients do not achieve a partial response, and ultimately all patients undergo progression. Dara exerts anti-MM activity via antibody-dependent cell-mediated cytotoxicity (ADCC), antibody-dependent cellular phagocytosis (ADCP), complement-dependent cytotoxicity (CDC), and immunomodulatory effects. Deregulation of these pleiotropic mechanisms may cause development of Dara resistance. Knowledge of this resistance may improve the therapeutic management of MM patients.

The NOTCH1-HEY1 pathway regulates self-renewal and epithelial-mesenchymal transition of salivary adenoid cystic carcinoma cells

Our previous study demonstrated a close relationship between the NOTCH signaling pathway and salivary adenoid cystic carcinoma (SACC). Its receptor gene, NOTCH1, and its downstream gene, HES1, contribute to the proliferation, invasion and metastasis of SACC. Accumulating evidence supports HEY1 as another effector of the signaling pathway. The purpose of this study was to explore the effects of the NOTCH1-HEY1 pathway on the proliferation, invasion and metastasis of SACC cells. Our results verified that HEY1 is a specific molecular target of the NOTCH signaling pathway in SACC cells and that its expression in carcinoma is much higher than that in paracarcinoma tissues. The expression of NOTCH1 and HEY1 are positively correlated in the salivary adenoid cystic carcinoma tissues. NOTCH1 is significantly related to the activation of HEY1 in SACC, and that HEY1 reciprocally regulates NOTCH1 expression in SACC. HEY1 promotes cell proliferation and spheroid formation and inhibits cell apoptosis in vitro. In addition, HEY1 enhances the tumorigenicity of SACC in vivo. Furthermore, HEY1 increases cell invasion and metastasis by driving the expression of epithelial-mesenchymal transition (EMT)-related genes and MMPs. The results of this study indicate that the NOTCH1-HEY1 pathway is specifically upregulated in SACC and promotes cell proliferation, self-renewal, invasion, metastasis and the expression of EMT-related genes and MMPs. Our findings suggest that a NOTCH1-HEY1 pathway inhibitor might therefore have potential therapeutic applications in treating SACC patients by inhibiting cancer cell growth and metastasis.

Identification of Key Genes and Pathways in Myeloma side population cells by Bioinformatics Analysis

Background: Multiple myeloma (MM) is the second most common hematological malignancy, which is still incurable and relapses inevitably, highlighting further understanding of the possible mechanisms. Side population (SP) cells are a group of enriched progenitor cells showing stem-like phenotypes with a distinct low-staining pattern with Hoechst 33342. Compared to main population (MP) cells, the underlying molecular characteristics of SP cells remain largely unclear. This bioinformatics analysis aimed to identify key genes and pathways in myeloma SP cells to provide novel biomarkers, predict MM prognosis and advance potential therapeutic targets. Methods: The gene expression profile GSE109651 was obtained from Gene Expression Omnibus database, and then differentially expressed genes (DEGs) with P-value <0.05 and |log2 fold-change (FC)| > 2 were selected by the comparison of myeloma light-chain (LC) restricted SP (LC/SP) cells and MP CD138⁺ cells. Subsequently, gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) pathway enrichment analysis, protein-protein interaction (PPI) network analysis were performed to identify the functional enrichment analysis of the DEGs and screen hub genes. Cox proportional hazards regression was used to select the potential prognostic DEGs in training dataset (GSE2658). The prognostic value of the potential prognostic genes was evaluated by Kaplan-Meier curve and validated in another external dataset (MMRF-CoMMpass cohort from TCGA). Results: Altogether, 403 up-regulated and 393 down-regulated DEGs were identified. GO analysis showed that the up-regulated DEGs were significantly enriched in innate immune response, inflammatory response, plasma membrane and integral component of membrane, while the down-regulated DEGs were mainly involved in protoporphyrinogen IX and heme biosynthetic process, hemoglobin complex and erythrocyte differentiation. KEGG pathway analysis suggested that the DEGs were significantly enriched in osteoclast differentiation, porphyrin and chlorophyll metabolism and cytokine-cytokine receptor interaction. The top 10 hub genes, identified by the plug-in cytoHubba of the Cytoscape software using maximal clique centrality (MCC) algorithm, were ITGAM, MMP9, ITGB2, FPR2, C3AR1, CXCL1, CYBB, LILRB2, HP and FCER1G. Modules and corresponding GO enrichment analysis indicated that myeloma LC/SP cells were significantly associated with immune system, immune response and cell cycle. The predictive value of the prognostic model including TFF3, EPDR1, MACROD1, ARHGEF12, AMMECR1, NFATC2, HES6, PLEK2 and SNCA was identified, and validated in another external dataset (MMRF-CoMMpass cohort from TCGA). Conclusions: In conclusion, this study provides reliable molecular biomarkers for screening, prognosis, as well as novel therapeutic targets for myeloma LC/SP cells.

Insights into the Regulation of Tumor Angiogenesis by Micro-RNAs

One of the hallmarks of cancer is angiogenesis, a series of events leading to the formation of the abnormal vascular network required for tumor growth, development, progression, and metastasis. MicroRNAs (miRNAs) are short, single-stranded, non-coding RNAs whose functions include modulation of the expression of pro- and anti-angiogenic factors and regulation of the function of vascular endothelial cells. Vascular-associated microRNAs can be either pro- or anti-angiogenic. In cancer, miRNA expression levels are deregulated and typically vary during tumor progression. Experimental data indicate that the tumor phenotype can be modified by targeting miRNA expression. Based on these observations, miRNAs may be promising targets for the development of novel anti-angiogenic therapies. This review discusses the role of various miRNAs and their targets in tumor angiogenesis, describes the strategies and challenges of miRNA-based anti-angiogenic therapies and explores the potential use of miRNAs as biomarkers for anti-angiogenic therapy response.

Multiple myeloma exploits Jagged1 and Jagged2 to promote intrinsic and bone marrow-dependent drug resistance

Multiple myeloma is still incurable due to an intrinsic aggressiveness or, more frequently, to the interactions of malignant plasma cells with the bone marrow (BM) microenvironment. Myeloma cells educate BM cells to support neoplastic cell growth, survival, acquisition of drug resistance resulting in disease relapse. Myeloma microenvironment is characterized by Notch signaling hyperactivation due to the increased expression of Notch1 and 2 and the ligands Jagged1 and 2 in tumor cells. Notch activation influences myeloma cell biology and promotes the reprogramming of BM stromal cells. In this work we demonstrate, in vitro, ex vivo and by using a zebrafish multiple myeloma model, that Jagged inhibition causes a decrease in both myeloma-intrinsic and stromal cell-induced resistance to currently used drugs, i.e. bortezomib, lenalidomide and melphalan. The molecular mechanism of drug resistance involves the chemokine system CXCR4/SDF1α. Myeloma cell-derived Jagged ligands trigger Notch activity in BM stromal cells. These, in turn, secrete higher levels of SDF1α in the BM microenvironment increasing CXCR4 activation in myeloma cells, which is further potentiated by the concomitant increased expression of this receptor induced by Notch activation. Consistently with the augmented pharmacological resistance, SDF1α boosts the expression of BCL2, Survivin and ABCC1. These results indicate that a Jagged-tailored approach may contribute to disrupting the pharmacological resistance due to intrinsic myeloma cell features or to the pathological interplay with BM stromal cells and, conceivably, improve patients' response to standard-of-care therapies.

TRPM7, Magnesium, and Signaling

The transient receptor potential melastatin-subfamily member 7 (TRPM7) is a ubiquitously expressed chanzyme that possesses an ion channel permeable to the divalent cations Mg2+, Ca2+, and Zn2+, and an α-kinase that phosphorylates downstream substrates. TRPM7 and its homologue TRPM6 have been implicated in a variety of cellular functions and is critically associated with intracellular signaling, including receptor tyrosine kinase (RTK)-mediated pathways. Emerging evidence indicates that growth factors, such as EGF and VEGF, signal through their RTKs, which regulate activity of TRPM6 and TRPM7. TRPM6 is primarily an epithelial-associated channel, while TRPM7 is more ubiquitous. In this review we focus on TRPM7 and its association with growth factors, RTKs, and downstream kinase signaling. We also highlight how interplay between TRPM7, Mg2+ and signaling kinases influences cell function in physiological and pathological conditions, such as cancer and preeclampsia.