A MIR17HG-derived long noncoding RNA provides an essential chromatin scaffold for protein interaction and myeloma growth.

Long noncoding RNAs (lncRNAs) can drive tumorigenesis and are susceptible to therapeutic intervention. Here, we used a large-scale CRISPR interference viability screen to interrogate cell-growth dependency to lncRNA genes in multiple myeloma (MM) and identified a prominent role for the miR-17-92 cluster host gene (MIR17HG). We show that an MIR17HG-derived lncRNA, named lnc-17-92, is the main mediator of cell-growth dependency acting in a microRNA- and DROSHA-independent manner. Lnc-17-92 provides a chromatin scaffold for the functional interaction between c-MYC and WDR82, thus promoting the expression of ACACA, which encodes the rate-limiting enzyme of de novo lipogenesis acetyl-coA carboxylase 1. Targeting MIR17HG pre-RNA with clinically applicable antisense molecules disrupts the transcriptional and functional activities of lnc-17-92, causing potent antitumor effects both in vitro and in vivo in 3 preclinical animal models, including a clinically relevant patient-derived xenograft NSG mouse model. This study establishes a novel oncogenic function of MIR17HG and provides potent inhibitors for translation to clinical trials.

Targeting of mitochondrial fission through natural flavanones elicits anti-myeloma activity.

BACKGROUND: Mitochondrial alterations, often dependent on unbalanced mitochondrial dynamics, feature in the pathobiology of human cancers, including multiple myeloma (MM). Flavanones are natural flavonoids endowed with mitochondrial targeting activities. Herein, we investigated the capability of Hesperetin (Hes) and Naringenin (Nar), two aglycones of Hesperidin and Naringin flavanone glycosides, to selectively target Drp1, a pivotal regulator of mitochondrial dynamics, prompting anti-MM activity. METHODS: Molecular docking analyses were performed on the crystallographic structure of Dynamin-1-like protein (Drp1), using Hes and Nar molecular structures. Cell viability and apoptosis were assessed in MM cell lines, or in co-culture systems with primary bone marrow stromal cells, using Cell Titer Glo and Annexin V-7AAD staining, respectively; clonogenicity was determined using methylcellulose colony assays. Transcriptomic analyses were carried out using the Ion AmpliSeq™ platform; mRNA and protein expression levels were determined by quantitative RT-PCR and western blotting, respectively. Mitochondrial architecture was assessed by transmission electron microscopy. Real time measurement of oxygen consumption was performed by high resolution respirometry in living cells. In vivo anti-tumor activity was evaluated in NOD-SCID mice subcutaneously engrafted with MM cells. RESULTS: Hes and Nar were found to accommodate within the GTPase binding site of Drp1, and to inhibit Drp1 expression and activity, leading to hyperfused mitochondria with reduced OXPHOS. In vitro, Hes and Nar reduced MM clonogenicity and viability, even in the presence of patient-derived bone marrow stromal cells, triggering ER stress and apoptosis. Interestingly, Hes and Nar rewired MM cell metabolism through the down-regulation of master transcriptional activators (SREBF-1, c-MYC) of lipogenesis genes. An extract of Tacle, a Citrus variety rich in Hesperidin and Naringin, was capable to recapitulate the phenotypic and molecular perturbations of each flavanone, triggering anti-MM activity in vivo. CONCLUSION: Hes and Nar inhibit proliferation, rewire the metabolism and induce apoptosis of MM cells via antagonism of the mitochondrial fission driver Drp1. These results provide a framework for the development of natural anti-MM therapeutics targeting aberrant mitochondrial dependencies.

Combinatorial strategies targeting NEAT1 and AURKA as new potential therapeutic options for multiple myeloma.

Multiple myeloma (MM) is a dreadful disease, marked by the uncontrolled proliferation of clonal plasma cells (PCs) within the bone marrow (BM). MM is characterized by a highly heterogeneous clinical and molecular background, supported by severe genomic alterations. Important deregulation of long non-coding RNAs (lncRNAs) expression has been reported in MM patients, influencing progression and therapy resistance. NEAT1 is a lncRNA essential for nuclear paraspeckles and involved in gene expression regulation. We showed that NEAT1 supports MM proliferation making this lncRNA an attractive therapeutic candidate. Here, we used a combinatorial strategy integrating transcriptomic and computational approaches with functional high-throughput drug screening, to identify compounds that synergize with NEAT1 inhibition in restraining MM cells growth. AUKA inhibitors were identified as top-scoring drugs in these analyses. We showed that the combination of NEAT1 silencing and AURKA inhibitors in MM profoundly impairs microtubule organization and mitotic spindle assembly, finally leading to cell death. Analysis of the large publicly CoMMpass dataset showed that in MM patients AURKA expression is strongly associated with reduced progression-free (p < 0.0001) and overall survival probability (p < 0.0001) and patients displaying high expression levels of both NEAT1 and AURKA have a worse clinical outcome. Finally, using RNA-sequencing data from NEAT1 knockdown (KD) MM cells, we identified the AURKA allosteric regulator TPX2 as a new NEAT1 target in MM and as a mediator of the interplay between AURKA and NEAT1, therefore providing a possible explanation of the synergistic activity observed upon their combinatorial inhibition.

Mitochondrial dysfunction at the crossroad of cardiovascular diseases and cancer.

A large body of evidence indicates the existence of a complex pathophysiological relationship between cardiovascular diseases and cancer. Mitochondria are crucial organelles whose optimal activity is determined by quality control systems, which regulate critical cellular events, ranging from intermediary metabolism and calcium signaling to mitochondrial dynamics, cell death and mitophagy. Emerging data indicate that impaired mitochondrial quality control drives myocardial dysfunction occurring in several heart diseases, including cardiac hypertrophy, myocardial infarction, ischaemia/reperfusion damage and metabolic cardiomyopathies. On the other hand, diverse human cancers also dysregulate mitochondrial quality control to promote their initiation and progression, suggesting that modulating mitochondrial homeostasis may represent a promising therapeutic strategy both in cardiology and oncology. In this review, first we briefly introduce the physiological mechanisms underlying the mitochondrial quality control system, and then summarize the current understanding about the impact of dysregulated mitochondrial functions in cardiovascular diseases and cancer. We also discuss key mitochondrial mechanisms underlying the increased risk of cardiovascular complications secondary to the main current anticancer strategies, highlighting the potential of strategies aimed at alleviating mitochondrial impairment-related cardiac dysfunction and tumorigenesis. It is hoped that this summary can provide novel insights into precision medicine approaches to reduce cardiovascular and cancer morbidities and mortalities.

Activation of long non-coding RNA NEAT1 leads to survival advantage of multiple myeloma cells by supporting a positive regulatory loop with DNA repair proteins.

Long non-coding RNA NEAT1 is the core structural component of the nuclear paraspeckle (PS) organelles and it has been found to be deregulated in multiple myeloma (MM) patients. Experimental evidence indicated that NEAT1 silencing negatively impacts proliferation and viability of MM cells, both in vitro and in vivo, suggesting a role in DNA damage repair (DDR). In order to elucidate the biological and molecular relevance of NEAT1 upregulation in MM disease we exploited the CRISPR/Cas9 synergistic activation mediator genome editing system to engineer the AMO-1 MM cell line and generate two clones that para-physiologically transactivate NEAT1 at different levels. NEAT1 overexpression is associated with oncogenic and prosurvival advantages in MM cells exposed to nutrient starvation or a hypoxic microenvironment, which are stressful conditions often associated with more aggressive disease phases. Furthermore, we highlighted the NEAT1 involvement in virtually all DDR processes through, at least, two different mechanisms. On one side NEAT1 positively regulates the posttranslational stabilization of essential PS proteins, which are involved in almost all DDR systems, thus increasing their availability within cells. On the other hand, NEAT1 plays a crucial role as a major regulator of a molecular axis that includes ATM and the catalytic subunit of DNA-PK kinase proteins, and their direct targets pRPA32 and pCHK2. Overall, we provided novel important insightsthe role of NEAT1 in supporting MM cells adaptation to stressful conditions by improving the maintenance of DNA integrity. Taken together, our results suggest that NEAT1, and probably PS organelles, could represent a potential therapeutic target for MM treatment.

Natural Agents as Novel Potential Source of Proteasome Inhibitors with Anti-Tumor Activity: Focus on Multiple Myeloma.

Multiple myeloma (MM) is an aggressive and incurable disease for most patients, characterized by periods of treatment, remission and relapse. The introduction of new classes of drugs, such as proteasome inhibitors (PIs), has improved survival outcomes in these patient populations. The proteasome is the core of the ubiquitin-proteasome system (UPS), a complex and conserved pathway involved in the control of multiple cellular processes, including cell cycle control, transcription, DNA damage repair, protein quality control and antigen presentation. To date, PIs represent the gold standard for the treatment of MM. Bortezomib was the first PI approved by the FDA, followed by next generation of PIs, namely carfilzomib and ixazomib. Natural agents play an important role in anti-tumor drug discovery, and many of them have recently been reported to inhibit the proteasome, thus representing a new potential source of anti-MM drugs. Based on the pivotal biological role of the proteasome and on PIs' significance in the management of MM, in this review we aim to briefly summarize recent evidence on natural compounds capable of inhibiting the proteasome, thus triggering anti-MM activity.

Unraveling Mitochondrial Determinants of Tumor Response to Radiation Therapy.

Radiotherapy represents a highly targeted and efficient treatment choice in many cancer types, both with curative and palliative intents. Nevertheless, radioresistance, consisting in the adaptive response of the tumor to radiation-induced damage, represents a major clinical problem. A growing body of the literature suggests that mechanisms related to mitochondrial changes and metabolic remodeling might play a major role in radioresistance development. In this work, the main contributors to the acquired cellular radioresistance and their relation with mitochondrial changes in terms of reactive oxygen species, hypoxia, and epigenetic alterations have been discussed. We focused on recent findings pointing to a major role of mitochondria in response to radiotherapy, along with their implication in the mechanisms underlying radioresistance and radiosensitivity, and briefly summarized some of the recently proposed mitochondria-targeting strategies to overcome the radioresistant phenotype in cancer.

Exploiting MYC-induced PARPness to target genomic instability in multiple myeloma.

Multiple Myeloma (MM) is a hematologic malignancy strongly characterized by genomic instability, which promotes disease progression and drug resistance. Since we previously demonstrated that LIG3-dependent repair is involved in the genomic instability, drug resistance and survival of MM cells, we here investigated the biological relevance of PARP1, a driver component of Alternative-Non Homologous End Joining (Alt-NHEJ) pathway, in MM. We found a significant correlation between higher PARP1 mRNA expression and poor prognosis of MM patients. PARP1 knockdown or its pharmacological inhibition by Olaparib impaired MM cells viability in vitro and was effective against in vivo xenografts of human MM. Anti-proliferative effects induced by PARP1-inhibition were correlated to increase of DNA double-strand breaks, activation of DNA Damage Response (DDR) and finally apoptosis. Importantly, by comparing a gene expression signature of PARP inhibitors (PARPi) sensitivity to our plasma cell dyscrasia (PC) gene expression profiling (GEP), we identified a subset of MM patients which could benefit from PARP inhibitors. In particular, Gene Set Enrichment Analysis (GSEA) suggested that high MYC expression correlates to PARPi sensitivity in MM. Indeed, we identified MYC as promoter of PARP1-mediated repair in MM and, consistently, we demonstrate that cytotoxic effects induced by PARP inhibition are mostly detectable on MYC-proficient MM cells. Taken together, our findings indicate that MYC-driven MM cells are addicted to PARP1 Alt-NHEJ repair, which represents therefore a druggable target in this still incurable disease.

ZNF521 Enhances MLL-AF9-Dependent Hematopoietic Stem Cell Transformation in Acute Myeloid Leukemias by Altering the Gene Expression Landscape.

Leukemias derived from the MLL-AF9 rearrangement rely on dysfunctional transcriptional networks. ZNF521, a transcription co-factor implicated in the control of hematopoiesis, has been proposed to sustain leukemic transformation in collaboration with other oncogenes. Here, we demonstrate that ZNF521 mRNA levels correlate with specific genetic aberrations: in particular, the highest expression is observed in AMLs bearing MLL rearrangements, while the lowest is detected in AMLs with FLT3-ITD, NPM1, or CEBPα double mutations. In cord blood-derived CD34+ cells, enforced expression of ZNF521 provides a significant proliferative advantage and enhances MLL-AF9 effects on the induction of proliferation and the expansion of leukemic progenitor cells. Transcriptome analysis of primary CD34+ cultures displayed subsets of genes up-regulated by MLL-AF9 or ZNF521 single transgene overexpression as well as in MLL-AF9/ZNF521 combinations, at either the early or late time points of an in vitro leukemogenesis model. The silencing of ZNF521 in the MLL-AF9 + THP-1 cell line coherently results in an impairment of growth and clonogenicity, recapitulating the effects observed in primary cells. Taken together, these results underscore a role for ZNF521 in sustaining the self-renewal of the immature AML compartment, most likely through the perturbation of the gene expression landscape, which ultimately favors the expansion of MLL-AF9-transformed leukemic clones.

Oleil Hydroxytyrosol (HTOL) Exerts Anti-Myeloma Activity by Antagonizing Key Survival Pathways in Malignant Plasma Cells.

Polyphenols from olive oil are endowed with several biological activities. Chemical modifications have been recently applied to these compounds to improve their therapeutic activity in different pathological settings, including cancer. Herein, we describe the in vitro effects on multiple myeloma (MM) cells of oleil hydroxytyrosol (HTOL), a synthetic fatty ester of natural hydroxytyrosol with oleic acid. HTOL reduced the viability of various human MM cell lines (HMCLs), even when co-cultured with bone marrow stromal cells, triggering ER stress, UPR and apoptosis, while it was not cytotoxic against healthy peripheral blood mononuclear cells or B lymphocytes. Whole-transcriptome profiling of HTOL-treated MM cells, coupled with protein expression analyses, indicate that HTOL antagonizes key survival pathways for malignant plasma cells, including the undruggable IRF4-c-MYC oncogenic axis. Accordingly, c-MYC gain- and loss-of-function strategies demonstrate that HTOL anti-tumor activity was, at least in part, due to c-MYC targeting. Taken together, these findings underscore the anti-MM potential of HTOL, providing the molecular framework for further investigation of HTOL-based treatments as novel anti-cancer agents.

Therapeutic vulnerability of multiple myeloma to MIR17PTi, a first-in-class inhibitor of pri-miR-17-92.

The microRNA (miRNA) cluster miR-17-92 is oncogenic and represents a valuable therapeutic target in c-MYC (MYC)-driven malignancies. Here, we developed novel LNA gapmeR antisense oligonucleotides (ASOs) to induce ribonuclease H-mediated degradation of MIR17HG primary transcripts and consequently prevent biogenesis of miR-17-92 miRNAs (miR-17-92s). The leading LNA ASO, MIR17PTi, impaired proliferation of several cancer cell lines (n = 48) established from both solid and hematologic tumors by on-target antisense activity, more effectively as compared with miR-17-92 inhibitors. By focusing on multiple myeloma (MM), we found that MIR17PTi triggers apoptosis via impairment of homeostatic MYC/miR-17-92 feed-forward loops (FFLs) in patient-derived MM cells and induces MYC-dependent synthetic lethality. We show that alteration of a BIM-centered FFL is instrumental for MIR17PTi to induce cytotoxicity in MM cells. MIR17PTi exerts strong in vivo antitumor activity in nonobese diabetic severe combined immunodeficient mice bearing clinically relevant models of MM, with advantageous safety and pharmacokinetic profiles in nonhuman primates. Altogether, MIR17PTi is a novel pharmacological tool to be tested in early-phase clinical trials against MM and other MYC-driven malignancies.

Functional role and therapeutic targeting of p21-activated kinase 4 in multiple myeloma.

Dysregulated oncogenic serine/threonine kinases play a pathological role in diverse forms of malignancies, including multiple myeloma (MM), and thus represent potential therapeutic targets. Here, we evaluated the biological and functional role of p21-activated kinase 4 (PAK4) and its potential as a new target in MM for clinical applications. PAK4 promoted MM cell growth and survival via activation of MM survival signaling pathways, including the MEK-extracellular signal-regulated kinase pathway. Furthermore, treatment with orally bioavailable PAK4 allosteric modulator (KPT-9274) significantly impacted MM cell growth and survival in a large panel of MM cell lines and primary MM cells alone and in the presence of bone marrow microenvironment. Intriguingly, we have identified FGFR3 as a novel binding partner of PAK4 and observed significant activity of KPT-9274 against t(4;14)-positive MM cells. This set of data supports PAK4 as an oncogene in myeloma and provide the rationale for the clinical evaluation of PAK4 modulator in myeloma.

Turning Stem Cells Bad: Generation of Clinically Relevant Models of Human Acute Myeloid Leukemia through Gene Delivery- or Genome Editing-Based Approaches.

Acute myeloid leukemia (AML), the most common acute leukemia in the adult, is believed to arise as a consequence of multiple molecular events that confer on primitive hematopoietic progenitors unlimited self-renewal potential and cause defective differentiation. A number of genetic aberrations, among which a variety of gene fusions, have been implicated in the development of a transformed phenotype through the generation of dysfunctional molecules that disrupt key regulatory mechanisms controlling survival, proliferation, and differentiation in normal stem and progenitor cells. Such genetic aberrations can be recreated experimentally to a large extent, to render normal hematopoietic stem cells "bad", analogous to the leukemic stem cells. Here, we wish to provide a brief outline of the complementary experimental approaches, largely based on gene delivery and more recently on gene editing, employed over the last two decades to gain insights into the molecular mechanisms underlying AML development and progression and on the prospects that their applications offer for the discovery and validation of innovative therapies.

Protective Role of GPER Agonist G-1 on Cardiotoxicity Induced by Doxorubicin.

The use of Doxorubicin (Dox), a frontline drug for many cancers, is often complicated by dose-limiting cardiotoxicity in approximately 20% of patients. The G-protein estrogen receptor GPER/GPR30 mediates estrogen action as the cardioprotection under certain stressful conditions. For instance, GPER activation by the selective agonist G-1 reduced myocardial inflammation, improved immunosuppression, triggered pro-survival signaling cascades, improved myocardial mechanical performance, and reduced infarct size after ischemia/reperfusion (I/R) injury. Hence, we evaluated whether ligand-activated GPER may exert cardioprotection in male rats chronically treated with Dox. 1 week of G-1 (50 µg/kg/day) intraperitoneal administration mitigated Dox (3 mg/kg/day) adverse effects, as revealed by reduced TNF-α, IL-1ß, LDH, and ROS levels. Western blotting analysis of cardiac homogenates indicated that G-1 prevents the increase in p-c-jun, BAX, CTGF, iNOS, and COX2 expression induced by Dox. Moreover, the activation of GPER rescued the inhibitory action elicited by Dox on the expression of BCL2, pERK, and pAKT. TUNEL assay indicated that GPER activation may also attenuate the cardiomyocyte apoptosis upon Dox exposure. Using ex vivo Langendorff perfused heart technique, we also found an increased systolic recovery and a reduction of both infarct size and LDH levels in rats treated with G-1 in combination with Dox respect to animals treated with Dox alone. Accordingly, the beneficial effects induced by G-1 were abrogated in the presence of the GPER selective antagonist G15. These data suggest that GPER activation mitigates Dox-induced cardiotoxicity, thus proposing GPER as a novel pharmacological target to limit the detrimental cardiac effects of Dox treatment. J. Cell. Physiol. 232: 1640-1649, 2017. © 2016 Wiley Periodicals, Inc.

Ex-vivo characterization of circulating colon cancer cells distinguished in stem and differentiated subset provides useful biomarker for personalized metastatic risk assessment.

BACKGROUND: Circulating tumor cells (CTCs) represent one of the most interesting target in improving diagnosis, prognosis and treatment. Herein we evaluate the possibility of using an emo-cytometric approach on the evaluation of the heterogeneous population of CTCs to improve personalized metastatic risk assessment. We benchmarked ex vivo behavior of distinct subsets of circulating colon tumor cells with correspondent clinical behavior of patients from which we isolated CTCs. METHODS: Isolation and CTC expansion were performed by a gradient protocol. In vitro characterization was determined by flow cytometry, immunofluorescence, western blotting and proteomic profiling. Cell sorter was performed with immunomagnetic beads. Confocal microscopy was used to evaluate tissue sections. Kaplan Mayer curves was cared for through Medcalc program. RESULTS: We collected heterogeneous CTCs, derived from the whole blood of seven patients affected by colon cancer, expressing CD133(pos)CD45(neg) (5 ± 1) and (2 ± 1) and CK20(pos)CD45(neg) of (29 ± 3) (11 ± 1) cells/ml in Dukes D and A stage respectively. Proliferation rate of 57 ± 16 %, expression for CXCR4(pos) of 18 ± 7 % and detectable levels of IL-6, IL-8 and SDF-1 cytokines in conditioned culture medium characterized short-time expanded-CTCs (eCTCs). ECTCs organized in tumor sphere were CD45(neg)CD133(pos) while in adhesion were CXCR4(pos)CK20(pos). These two subsets were separately injected in mice. The first group of xenografts developed superficial lesions within 2 weeks. In the second group, in absence of growing tumour, the survival of injected eCTCs was monitored through SDF-1 serum levels detection. The detection of human cancer cells expressing CK20, in mice tissues sections, suggested a different biological behaviour of injected eCTC-subsets: tumorigenic for the first and disseminating for the second. The benchmarking of the experimental data with the clinical course highlights that patients with prevalence of circulating cancer stem cells (CD45(neg)CD133(pos)) have a lower overall survival. Conversely, patients with prevalence of circulating differentiated cells (CXCR4(pos)CK20(pos)) have a low disease-free survival. CONCLUSION: On the basis of the heterogeneous composition and despite the low number of CTCs, it was possible to distinguish two subgroups of CTCs, suggesting a different clinical outcome. CTC-subsets detailing is useful to better define the metastatic-risk personalized score thus improving disease management and reducing patient care cost.

MYD88-independent growth and survival effects of Sp1 transactivation in Waldenstrom macroglobulinemia.

Sp1 transcription factor controls a pleiotropic group of genes and its aberrant activation has been reported in a number of malignancies, including multiple myeloma. In this study, we investigate and report its aberrant activation in Waldenström macroglobulinemia (WM). Both loss of and gain of Sp1 function studies have highlighted a potential oncogenic role of Sp1 in WM. We have further investigated the effect of a small molecule inhibitor, terameprocol (TMP), targeting Sp1 activity in WM. Treatment with TMP inhibited the growth and survival and impaired nuclear factor-κB and signal transducer and activator of transcription activity in WM cells. We next investigated and observed that TMP treatment induced further inhibition of WM cells in MYD88 knockdown WM cells. Moreover, we observed that Bruton's tyrosine kinase, a downstream target of MYD88 signaling pathway, is transcriptionally regulated by Sp1 in WM cells. The combined use of TMP with Bruton's tyrosine kinase or interleukin-1 receptor-associated kinase 1 and 4 inhibitors resulted in a significant and synergistic dose-dependent antiproliferative effect in MYD88-L265P-expressing WM cells. In summary, these results demonstrate Sp1 as an important transcription factor that regulates proliferation and survival of WM cells independent of MYD88 pathway activation, and provide preclinical rationale for clinical development of TMP in WM alone or in combination with inhibitors of MYD88 pathway.

A p53-dependent tumor suppressor network is induced by selective miR-125a-5p inhibition in multiple myeloma cells.

The analysis of deregulated microRNAs (miRNAs) is emerging as a novel approach to disclose the regulation of tumor suppressor or tumor promoting pathways in tumor cells. Targeting aberrantly expressed miRNAs is therefore a promising strategy for cancer treatment. By miRNA profiling of primary plasma cells from multiple myeloma (MM) patients, we previously reported increased miR-125a-5p levels associated to specific molecular subgroups. On these premises, we aimed at investigating the biological effects triggered by miR-125a-5p modulation in MM cells. Expression of p53 pathway-related genes was down-regulated in MM cells transfected with miR-125a-5p mimics. Luciferase reporter assays confirmed specific p53 targeting at 3'UTR level by miR-125a-5p mimics. Interestingly, bone marrow stromal cells (BMSCs) affected the miR-125a-5p/p53 axis, since adhesion of MM cells to BMSCs strongly up-regulated miR-125a-5p levels, while reduced p53 expression. Moreover, ectopic miR-125a-5p reduced, while miR-125-5p inhibitors promoted, the expression of tumor suppressor miR-192 and miR-194, transcriptionally regulated by p53. Lentiviral-mediated stable inhibition of miR-125a-5p expression in wild-type p53 MM cells dampened cell growth, increased apoptosis and reduced cell migration. Importantly, inhibition of in vitro MM cell proliferation and migration was also achieved by synthetic miR-125a-5p inhibitors and was potentiated by the co-expression of miR-192 or miR-194. Taken together, our data indicate that miR-125a-5p antagonism results in the activation of p53 pathway in MM cells, underlying the crucial role of this miRNA in the biopathology of MM and providing the molecular rationale for the combinatory use of miR-125a inhibitors and miR-192 or miR-194 mimics for MM treatment.

Canonical and noncanonical Hedgehog pathway in the pathogenesis of multiple myeloma.

The Hedgehog (Hh) pathway is required for cell-fate determination during the embryonic life, as well as cell growth and differentiation in the adult organism, where the inappropriate activation has been implicated in several cancers. Here we demonstrate that Hh signaling plays a significant role in growth and survival of multiple myeloma (MM) cells. We observed that CD138(+) MM cells express Hh genes and confirmed Smoothened (Smo)-dependent Hh signaling in MM using a novel synthetic Smo inhibitor, NVP-LDE225 (Novartis), which decreased MM cell viability by inducing specific down-regulation of Gli1 and Ptch1, hallmarks of Hh activity. In addition, we detected a nuclear localization of Gli1 in MM cells, which is completely abrogated by Forskolin, a Gli1-modulating compound, confirming Smo-independent mechanisms leading to Hh activation in MM. Finally, we identified that bone marrow stromal cells are a source of the Shh ligand, although they are resistant to the Hh inhibitor because of defective Smo expression and Ptch1 up-regulation. Further in vitro as well as in vivo studies showed antitumor efficacy of NVP-LDE225 in combination with bortezomib. Altogether, our data demonstrate activation of both canonical and noncanonical Hh pathway in MM, thus providing the rationale for testing Hh inhibitors in clinical trials to improve MM patient outcome.

Circulating miRNAs as Novel Clinical Biomarkers in Temporal Lobe Epilepsy.

Temporal lobe epilepsy (TLE) represents the most common form of refractory focal epilepsy. The identification of innovative clinical biomarkers capable of categorizing patients with TLE, allowing for improved treatment and outcomes, still represents an unmet need. Circulating microRNAs (c-miRNAs) are short non-coding RNAs detectable in body fluids, which play crucial roles in the regulation of gene expression. Their characteristics, including extracellular stability, detectability through non-invasive methods, and responsiveness to pathological changes and/or therapeutic interventions, make them promising candidate biomarkers in various disease settings. Recent research has investigated c-miRNAs in various bodily fluids, including serum, plasma, and cerebrospinal fluid, of TLE patients. Despite some discrepancies in methodologies, cohort composition, and normalization strategies, a common dysregulated signature of c-miRNAs has emerged across different studies, providing the basis for using c-miRNAs as novel biomarkers for TLE patient management.