Downregulation of specific miRNAs in hyperdiploid multiple myeloma mimics the oncogenic effect of IgH translocations occurring in the non-hyperdiploid subtype

TACC3: a multi-functional protein promoting cancer cell survival and aggressiveness

TACC3 is the most oncogenic member of the transforming acidic coiled-coil domain-containing protein (TACC) family. It is one of the major recruitment factors of distinct multi-protein complexes. TACC3 is localized to spindles, centrosomes, and nucleus, and regulates key oncogenic processes, including cell proliferation, migration, invasion, and stemness. Recently, TACC3 inhibition has been identified as a vulnerability in highly aggressive cancers, such as cancers with centrosome amplification (CA). TACC3 has spatiotemporal functions throughout the cell cycle; therefore, targeting TACC3 causes cell death in mitosis and interphase in cancer cells with CA. In the clinics, TACC3 is highly expressed and associated with worse survival in multiple cancers. Furthermore, TACC3 is a part of one of the most common fusions of FGFR, FGFR3-TACC3 and is important for the oncogenicity of the fusion. A detailed understanding of the regulation of TACC3 expression, its key partners, and molecular functions in cancer cells is vital for uncovering the most vulnerable tumors and maximizing the therapeutic potential of targeting this highly oncogenic protein. In this review, we summarize the established and emerging interactors and spatiotemporal functions of TACC3 in cancer cells, discuss the potential of TACC3 as a biomarker in cancer, and therapeutic potential of its inhibition.

Biological research on the occurrence and development of multiple myeloma and its treatment

INTRODUCTION

To review the pathogenesis and treatment of multiple myeloma (MM). MM is a hematological malignancy with abnormal plasma cell proliferation in bone marrow. Due to the emergence of drug resistance, MM is still an incurable malignancy, which requires further exploration of pathogenesis and effective therapeutic targets.

METHODS

In this paper, the method of literature review is adopted to obtain the information about MM. Based on the literature, comprehensive and systematic review is made.

RESULTS

MM is a complex pathophysiological process with great heterogeneity, mainly reflected in genomic instability and bone marrow microenvironment. At present, the treatment of MM has made great progress, proteasome inhibitors and immunomodulatory drugs are widely used in clinic. Allogeneic stem cell transplantation may be the only promising cure for MM, and its high transplant-related mortality limits its clinical application.

CONCLUSIONS

The future of MM treatment lies in the development of more targeted therapies, novel immunotherapies, and a better understanding of the disease's molecular and genetic basis.

Regulatory Mechanisms of Epigenetic miRNA Relationships in Human Cancer and Potential as Therapeutic Targets

Simple Summary

By the virtue of targeting multiple genes, a microRNA (miRNA) can infer variable consequences on tumorigenesis by appearing as both a tumour suppressor and oncogene. miRNAs can regulate gene expression by modulating genome-wide epigenetic status of genes that are involved in various cancers. These miRNAs perform direct inhibition of key mediators of the epigenetic machinery, such as DNA methyltransferases (DNMTs) and histone deacetylases (HDACs) genes. Along with miRNAs gene expression, similar to other protein-coding genes, miRNAs are also controlled by epigenetic mechanisms. Overall, this reciprocal interaction between the miRNAs and the epigenetic architecture is significantly implicated in the aberrant expression of miRNAs detected in various human cancers. Comprehensive knowledge of the miRNA-epigenetic dynamics in cancer is essential for the discovery of novel anticancer therapeutics.

Abstract

Initiation and progression of cancer are under both genetic and epigenetic regulation. Epigenetic modifications including alterations in DNA methylation, RNA and histone modifications can lead to microRNA (miRNA) gene dysregulation and malignant cellular transformation and are hereditary and reversible. miRNAs are small non-coding RNAs which regulate the expression of specific target genes through degradation or inhibition of translation of the target mRNA. miRNAs can target epigenetic modifier enzymes involved in epigenetic modulation, establishing a trilateral regulatory “epi–miR–epi” feedback circuit. The intricate association between miRNAs and the epigenetic architecture is an important feature through which to monitor gene expression profiles in cancer. This review summarises the involvement of epigenetically regulated miRNAs and miRNA-mediated epigenetic modulations in various cancers. In addition, the application of bioinformatics tools to study these networks and the use of therapeutic miRNAs for the treatment of cancer are also reviewed. A comprehensive interpretation of these mechanisms and the interwoven bond between miRNAs and epigenetics is crucial for understanding how the human epigenome is maintained, how aberrant miRNA expression can contribute to tumorigenesis and how knowledge of these factors can be translated into diagnostic and therapeutic tool development.

LRP1B Polymorphisms Are Associated with Multiple Myeloma Risk in a Chinese Han Population

Multiple myeloma (MM) is an extremely complex plasma cell malignancy that is genetically heterogeneous. A recent Genome-wide association study (GWAS) indicated that variation at 2q22 (rs61070260) influences MM risk. This association has not been validated to date in a Chinese Han population. In this study, we evaluated the association between rs61070260 in LRP1B and MM risk in a Chinese Han population involving 739 MM patients and 592 healthy controls. Our results indicated that rs61070260 in LRP1B was significantly associated with MM susceptibility (P=3.937×10-37). Furthermore, the linkage disequilibrium (LD) analysis of rs61070260 revealed an LD block encompassing exons 26, 27 and 28 of the LRP1B gene, and a subsequent sequencing analysis identified three SNPs (rs762074421, rs756168629, rs113600691) in exons 26 and 28 of LRP1B. For the SNP rs756168629 in exon 26, a missense mutation which results in a transition from arginine to histidine at position 1661 of the LRP1B protein, has not been found in Chinese populations according to the Chinese Millionome Database and Genome Aggregation Database (EAS), and this mutation was predicted to be deleterious or damaging by SIFT and PolyPhen. These findings firmly establish the role of LRP1B in contributing to MM susceptibility. In addition, the identification of a rare coding mutation (p.R1661H) in LRP1B detected in MM individuals was suggested to be harmful to the encoded protein, which was characterized as a candidate tumour suppressor; thus, LRP1B is likely to be a disease-associated gene that is implicated in the development and progression of MM.

Transcription factor MafB contributes to the activation of spinal microglia underlying neuropathic pain development

Microglia, which are pathological effectors and amplifiers in the central nervous system, undergo various forms of activation. A well-studied microglial-induced pathological paradigm, spinal microglial activation following peripheral nerve injury (PNI), is a key event for the development of neuropathic pain but the transcription factors contributing to microglial activation are less understood. Herein, we demonstrate that MafB, a dominant transcriptional regulator of mature microglia, is involved in the pathology of a mouse model of neuropathic pain. PNI caused a rapid and marked increase of MafB expression selectively in spinal microglia but not in neurons. We also found that the microRNA mir-152 in the spinal cord which targets MafB expression decreased after PNI, and intrathecal administration of mir-152 mimic suppressed the development of neuropathic pain. Reduced MafB expression using heterozygous Mafb deficient mice and by intrathecal administration of siRNA alleviated the development of PNI-induced mechanical hypersensitivity. Furthermore, we found that intrathecal transfer of Mafb deficient microglia did not induce mechanical hypersensitivity and that conditional Mafb knockout mice did not develop neuropathic pain after PNI. We propose that MafB is a key mediator of the PNI-induced phenotypic alteration of spinal microglia and neuropathic pain development.

miR-24-3p/FGFR3 Signaling as a Novel Axis Is Involved in Epithelial-Mesenchymal Transition and Regulates Lung Adenocarcinoma Progression

Our previous studies showed that Fibroblast growth factor receptor 3 (FGFR3) contributed to cell growth in lung cancer. However, the correlation between FGFR3 and tumor progression, coupled with the underlying mechanisms, are not fully understood. The clinical significance of FGFR3 was determined in two cohorts of clinical samples (n = 22, n = 78). A panel of biochemical assays and functional experiments was utilized to elucidate the underlying mechanisms and effects of FGFR3 and miR-24-3p on lung adenocarcinoma progression. Upregulated FGFR3 expression indicated an adverse prognosis for lung adenocarcinoma individuals and promoted metastatic potential of lung adenocarcinoma cells. Owing to the direct regulation towards FGFR3, miR-24-3p could interfere with the potential of proliferation, migration, and invasion in lung adenocarcinoma, following variations of EMT-related protein expression. As a significant marker of EMT, E-cadherin was negatively correlated with FGFR3, of which ectopic overexpression could neutralize the antitumour effects of miR-24-3p and reverse its regulatory effects on EMT markers. Taken together, these findings define a novel insight into the miR-24-3p/FGFR3 signaling axis in regulating lung adenocarcinoma progression and suggest that targeting the miR-24-3p/FGFR3 axis could be an effective and efficient way to prevent tumor progression.

Expression of the miR-148/152 Family in Acute Myeloid Leukemia and its Clinical Significance

Background

MicroRNAs (miRNAs) play an important role in the development and progression of acute myeloid leukemia (AML). The miR-148/152 family has been reported to be express differently in various kinds of tumors. We investigated the expression level of the miR-148/152 family in AML patients and their clinical significance.

Material/Methods

Expression levels of the miR-148/152 family in 80 patients with newly diagnosed AML and 20 healthy participants were analyzed by qRT-PCR. We also evaluated the relationship between the expression levels of the miR-148/152 family and clinicopathological features of AML patients.

Results

Compared with healthy controls, we found a significant lower expression of downregulated miR-148/152 in AML patients (p<0.0001). The expression of miR148/152 family was associated with various AML clinicopathological risk parameters including FAB classifications, cytogenetics, and gene mutations. The number of patients with high expression levels of miR-148a/b was significantly increased in the low-risk group and significantly decreased in the high-risk group. (p=0.025, p=0.000, respectively). Patients with higher expression of miR-148b showed a higher complete remission (CR) rate (p=0.043). Importantly, higher expression of miR-148a/b was correlated with lower relapse rate (p=0.035, p=0.027, respectively) and showed a longer relapse-free survival (RFS) (p=0.0321, p=0.002, respectively). In the subgroup analysis, RFS was significantly affected by the expression of miR-148a/b in patients the high and the intermediate-risk groups (p=0.0499, p=0.0114, respectively).

Conclusions

The expression levels of the miR-148/152 family were lower in patients with AML compared to healthy controls, and were associated with various AML clinicopathological parameters and therapeutic effect. The miR-148/152 family may prove to be a new biomarker for AML.

MicroRNA‑494 inhibits nerve growth factor‑induced cell proliferation by targeting cyclin D1 in human corneal epithelial cells

Nerve growth factor (NGF) is expressed in the human corneal epithelium and stroma. It is an efficient therapy for human corneal ulcers caused by neurotropic disease. However, little is known about the molecular mechanism of NGF in healing human corneal epithelial diseases. Numerous microRNAs (miRNAs) are expressed in the cornea and miRNAs have important roles in regulating corneal development. In the present study, novel miRNA regulators were demonstrated to be involved in NGF‑induced human corneal epithelial cell (hCEC) proliferation. NGF treatment significantly downregulated the expression of miRNA‑494 in hCECs in vitro. Furthermore, miRNA‑494 increased G1 arrest in the immortalized human corneal epithelial cell (ihCEC) line and suppressed cell proliferation. Accordingly, bioinformatics programs and luciferase reporter assay demonstrated that miRNA‑494 directly targeted cyclin D1 by binding to a sequence in the 3'‑untranslated region. In addition, overexpression of miRNA‑494 decreased both basal and NGF‑induced cyclin D1 expression. NGF treatment partially suppressed miRNA‑494 expression and restored cyclin D1 expression. Furthermore, co‑transfection of miRNA‑494 with the cyclin D1 ORF clone partially restored cyclin D1 mRNA and protein expression. These findings indicate that miRNA‑494 and its target cyclin D1 may be a crucial axis for NGF in regulating the proliferation of hCEC. Specific modulation of miRNA‑494 in hCEC could represent an attractive approach for treating cornea epithelial diseases.

The therapeutic potential of cell cycle targeting in multiple myeloma

Proper cell cycle progression through the interphase and mitosis is regulated by coordinated activation of important cell cycle proteins (including cyclin-dependent kinases and mitotic kinases) and several checkpoint pathways. Aberrant activity of these cell cycle proteins and checkpoint pathways results in deregulation of cell cycle progression, which is one of the key hallmarks of cancer. Consequently, intensive research on targeting these cell cycle regulatory proteins identified several candidate small molecule inhibitors that are able to induce cell cycle arrest and even apoptosis in cancer cells. Importantly, several of these cell cycle regulatory proteins have also been proposed as therapeutic targets in the plasma cell malignancy multiple myeloma (MM). Despite the enormous progress in the treatment of MM the past 5 years, MM still remains most often incurable due to the development of drug resistance. Deregulated expression of the cyclins D is observed in virtually all myeloma patients, emphasizing the potential therapeutic interest of cyclin-dependent kinase inhibitors in MM. Furthermore, other targets have also been identified in MM, such as microtubules, kinesin motor proteins, aurora kinases, polo-like kinases and the anaphase promoting complex/cyclosome. This review will provide an overview of the cell cycle proteins and checkpoint pathways deregulated in MM and discuss the therapeutic potential of targeting proteins or protein complexes involved in cell cycle control in MM.

miR clusters target cellular functional complexes by defining their degree of regulatory freedom

Using the two paralog miR-23∼27∼24 clusters as an example and combining experimental and clinical data in a systematical approach to microRNA (miR) function and dysregulation, a complex picture of their roles in cancer is drawn. Various findings appear to be contradictory to a larger extent and cannot be fully explained by the classical regulatory network models and feedback loops that are mainly considered by one-to-one regulatory interactions of the involved molecules. Here, we propose an extended model of the regulatory role of miRs that, at least, supplements the usually considered single/oligo-target regulation of certain miRs. The cellular availability of the participating miR members in this model reflects an upper hierarchy level of intracellular and extracellular environmental influences, such as neighboring cells, soluble factors, hypoxia, chemotherapeutic drugs, and irradiation, among others. The novel model is based on the understanding of cellular functional complexes, such as for apoptosis, migration, and proliferation. These complexes consist of many regulatory components that can be targeted by miR cluster members to a different extent but may affect the functional complex in different ways. We propose that the final miR-related effect is a result of the possible degree of regulatory freedom provided by the miR effects on the whole functional complex structure. This degree of regulatory freedom defines to which extent the cellular functional complex can react in response to regulatory triggers, also understood as sensitization (more regulatory response options) or de-sensitization (less regulatory response options) of the system rather than single molecules.

Next-Generation Sequencing Informing Therapeutic Decisions and Personalized Approaches

Multiple myeloma is a heterogeneous disease featured by different molecular subtypes. In the last decade, new therapeutics including second- and third-generation proteasome inhibitors and immunomodulatory agents, monoclonal antibodies, and other novel targeted agents have completely transformed the outcome of the disease. The task ahead is to develop strategies to identify effective combinations and sequences of agents that can exploit the genetic make-up of myeloma cells to improve efficacy. Moreover, a subgroup of high-risk patients who experience early disease relapse and shorter survival also requires early identification and specific intervention. Next-generation sequencing (NGS) technologies now allow us to accomplish some of these goals. As described here, besides improving our understanding of the disease, it is beginning to influence our clinical decisions and therapeutic choices. In this article, we describe the current state-of-the-art role of NGS in myeloma from identifying high-risk disease, to drug selection, and, ultimately, to guide personalized therapy.

Polydatin protects the respiratory system from PM2.5 exposure

Atmospheric particle is one of the risk factors for respiratory disease; however, their injury mechanisms are poorly understood, and prevention methods are highly desirable. We constructed artificial PM_2.5 (aPM_2.5) particles according to the size and composition of actual PM_2.5 collected in Beijing. Using these artificial particles, we created an inhalation-injury animal model. These aPM_2.5 particles simulate the physical and chemical characteristics of the actual PM_2.5, and inhalation of the aPM_2.5 in rat results in a time-dependent change in lung suggesting a declined lung function, injury from oxidative stress and inflammation in lung. Thus, this aPM_2.5-caused injury animal model may mimic that of the pulmonary injury in human exposed to airborne particles. In addition, polydatin (PD), a resveratrol glucoside that is rich in grapes and red wine, was found to significantly decrease the oxidative potential (OP) of aPM_2.5in vitro. Treating the model rats with PD prevented the lung function decline caused by aPM_2.5, and reduced the level of oxidative damage in aPM_2.5-exposed rats. Moreover, PD inhibited aPM_2.5-induced inflammation response, as evidenced by downregulation of white blood cells in bronchoalveolar lavage fluid (BALF), inflammation-related lipids and proinflammation cytokines in lung. These results provide a practical means for self-protection against particulate air pollution.

Downregulation of MicroRNA-152 contributes to high expression of DKK1 in multiple myeloma

Multiple myeloma (MM) induced bone lesion is one of the most crippling characteristics, and the MM secreted Dickkopf-1 (DKK1) has been reported to play important role in this pathologic process. However, the underlying regulation mechanisms involved in DKK1 expression are still unclear. In this study, we validated the expression patterns of microRNA (miR) 15a, 34a, 152, and 223 in MM cells and identified that miR-152 was significantly downregulated in the MM group compared with the non-MM group, and that miR-152 level was negatively correlated with the expression of DKK1 in the MM cells. Mechanistic studies showed that manipulating miR-152 artificially in MM cells led to changes in DKK-1 expression, and miR-152 blocked DKK1 transcriptional activity by binding to the 3'UTR of DKK1 mRNA. Importantly, we revealed that MM cells stably expressing miR-152 improved the chemotherapy sensitivity, and counteracted the bone disruption in an intrabone-MM mouse model. Our study contributes better understanding of the regulation mechanism of DKK-1 in MM, and opens up the potential for developing newer therapeutic strategies in the MM treatment.

Multiple myeloma cells modify VEGF/IL-6 levels and osteogenic potential of bone marrow stromal cells via Notch/miR-223

Bone marrow mesenchymal stromal cells (BMMSCs) represent a crucial component of multiple myeloma (MM) microenvironment supporting its progression and proliferation. Recently, microRNAs have become an important point of interest for research on micro-environmental interactions in MM with some evidence of tumor supportive roles in MM. In this study, we examined the role of miR-223 for MM support in BMMSCs of 56 patients with MM (MM-BMMSCs). miR-223 expression in MM-BMMSCs was reduced by the presence of MM cells in vitro in a cell-contact dependent manner compared to mono-cultured MM-BMMSCs. Co-cultivation of MM cells and MM-BMMSCs induced activation of notch amongst others via jagged-2/notch-2 leading to increased expression of Hes1, Hey2, or Hes5 in both cell types. Cultivation of MM-BMMSCs with increasing levels of recombinant jagged-2 reduced miR-223 and increased Hes1 levels in a concentration-dependent manner. Transient reduction of miR-223 levels increased VEGF and IL-6 expression and secretion by MM-BMMSCs. In addition, reduction of miR-223 degraded the osteogenic differentiation potential of MM-BMMSCs. Inhibition of notch signaling induced apoptosis in both MM cells and MM-BMMSCs. Furthermore, it increased miR-223 levels and reduced expression of VEGF and IL-6 by both cell types. These data provide first evidence that miR-223 participates in different MM supporting pathways in MM-BMMSCs inlcuding regulation of cytokine secretion and expression as well as osteogenic differentiation of MM-BMMSCs. More insights on the role of miR-223 in MM-BMMSCs and in cellular interactions between MM cells and MM-BMMSCs could provide starting points for a more efficient anti-myeloma treatment by targeting of notch signaling. © 2015 Wiley Periodicals, Inc.

Genomic heterogeneity in multiple myeloma

Multiple myeloma (MM) is an incurable malignancy in majority of patients characterized by clonal proliferation of plasma cells. To date, treatment is established based on general conditions and age of patients. However, MM is a heterogeneous disease, featured by various subtypes and different outcomes. Thus, the understanding of MM biology is currently a major challenge to eventually cure the disease. During the last decade, karyotype studies and gene expression profiling have identified robust prognostic markers as well as a widespread genomic landscape. More recently, studies of epigenetic, transcriptional modifications and next generation sequencing have allowed characterization of critical genes and pathways, clonal heterogeneity and mutational profiles involved in myelomagenesis. Altogether, these findings constitute important tools to develop new targeted and personalized therapies in MM.

miRGate: a curated database of human, mouse and rat miRNA-mRNA targets

MicroRNAs (miRNAs) are small non-coding elements involved in the post-transcriptional down-regulation of gene expression through base pairing with messenger RNAs (mRNAs). Through this mechanism, several miRNA-mRNA pairs have been described as critical in the regulation of multiple cellular processes, including early embryonic development and pathological conditions. Many of these pairs (such as miR-15 b/BCL2 in apoptosis or BART-6/BCL6 in diffuse large B-cell lymphomas) were experimentally discovered and/or computationally predicted. Available tools for target prediction are usually based on sequence matching, thermodynamics and conservation, among other approaches. Nevertheless, the main issue on miRNA-mRNA pair prediction is the little overlapping results among different prediction methods, or even with experimentally validated pairs lists, despite the fact that all rely on similar principles. To circumvent this problem, we have developed miRGate, a database containing novel computational predicted miRNA-mRNA pairs that are calculated using well-established algorithms. In addition, it includes an updated and complete dataset of sequences for both miRNA and mRNAs 3'-Untranslated region from human (including human viruses), mouse and rat, as well as experimentally validated data from four well-known databases. The underlying methodology of miRGate has been successfully applied to independent datasets providing predictions that were convincingly validated by functional assays. miRGate is an open resource available at http://mirgate.bioinfo.cnio.es. For programmatic access, we have provided a representational state transfer web service application programming interface that allows accessing the database at http://mirgate.bioinfo.cnio.es/API/ Database URL: http://mirgate.bioinfo.cnio.es

Drug resistance in multiple myeloma: latest findings and new concepts on molecular mechanisms

In the era of new and mostly effective therapeutic protocols, multiple myeloma still tends to be a hard-to-treat hematologic cancer. This hallmark of the disease is in fact a sequel to drug resistant phenotypes persisting initially or emerging in the course of treatment. Furthermore, the heterogeneous nature of multiple myeloma makes treating patients with the same drug challenging because finding a drugable oncogenic process common to all patients is not yet feasible, while our current knowledge of genetic/epigenetic basis of multiple myeloma pathogenesis is outstanding. Nonetheless, bone marrow microenvironment components are well known as playing critical roles in myeloma tumor cell survival and environment-mediated drug resistance happening most possibly in all myeloma patients. Generally speaking, however; real mechanisms underlying drug resistance in multiple myeloma are not completely understood. The present review will discuss the latest findings and concepts in this regard. It reviews the association of important chromosomal translocations, oncogenes (e.g. TP53) mutations and deranged signaling pathways (e.g. NFκB) with drug response in clinical and experimental investigations. It will also highlight how bone marrow microenvironment signals (Wnt, Notch) and myeloma cancer stem cells could contribute to drug resistance in multiple myeloma.

Global epigenetic regulation of microRNAs in multiple myeloma

Epigenetic changes frequently occur during tumorigenesis and DNA hypermethylation may account for the inactivation of tumor suppressor genes in cancer cells. Studies in Multiple Myeloma (MM) have shown variable DNA methylation patterns with focal hypermethylation changes in clinically aggressive subtypes. We studied global methylation patterns in patients with relapsed/refractory MM and found that the majority of methylation peaks were located in the intronic and intragenic regions in MM samples. Therefore, we investigated the effect of methylation on miRNA regulation in MM. To date, the mechanism by which global miRNA suppression occurs in MM has not been fully described. In this study, we report hypermethylation of miRNAs in MM and perform confirmation in MM cell lines using bisulfite sequencing and methylation-specific PCR (MSP) in the presence or absence of the DNA demethylating agent 5-aza-2'-deoxycytidine. We further characterized the hypermethylation-dependent inhibition of miR-152, -10b-5p and -34c-3p which was shown to exert a putative tumor suppressive role in MM. These findings were corroborated by the demonstration that the same miRNAs were down-regulated in MM patients compared to healthy individuals, alongside enrichment of miR-152-, -10b-5p, and miR-34c-3p-predicted targets, as shown at the mRNA level in primary MM cells. Demethylation or gain of function studies of these specific miRNAs led to induction of apoptosis and inhibition of proliferation as well as down-regulation of putative oncogene targets of these miRNAs such as DNMT1, E2F3, BTRC and MYCBP. These findings provide the rationale for epigenetic therapeutic approaches in subgroups of MM.

Cardio-miRNAs and onco-miRNAs: circulating miRNA-based diagnostics for non-cancerous and cancerous diseases

Cardiovascular diseases and cancers are the leading causes of morbidity and mortality in the world. MicroRNAs (miRNAs) are short non-coding RNAs that primarily repress target mRNAs. Here, miR-24, miR-125b, miR-195, and miR-214 were selected as representative cardio-miRs that are upregulated in human heart failure. To bridge the gap between miRNA studies in cardiology and oncology, the targets and functions of these miRNAs in cardiovascular diseases and cancers will be reviewed. ACVR1B, BCL2, BIM, eNOS, FGFR3, JPH2, MEN1, MYC, p16, and ST7L are miR-24 targets that have been experimentally validated in human cells. ARID3B, BAK1, BCL2, BMPR1B, ERBB2, FGFR2, IL6R, MUC1, SITR7, Smoothened, STAT3, TET2, and TP53 are representative miR-125b targets. ACVR2A, BCL2, CCND1, E2F3, GLUT3, MYB, RAF1, VEGF, WEE1, and WNT7A are representative miR-195 targets. BCL2L2, ß-catenin, BIM, CADM1, EZH2, FGFR1, NRAS, PTEN, TP53, and TWIST1 are representative miR-214 targets. miR-125b is a good cardio-miR that protects cardiomyocytes; miR-195 is a bad cardio-miR that elicits cardiomyopathy and heart failure; miR-24 and miR-214 are bi-functional cardio-miRs. By contrast, miR-24, miR-125b, miR-195, and miR-214 function as oncogenic or tumor suppressor miRNAs in a cancer (sub)type-dependent manner. Circulating miR-24 is elevated in diabetes, breast cancer and lung cancer. Circulating miR-195 is elevated in acute myocardial infarction, breast cancer, prostate cancer and colorectal adenoma. Circulating miR-125b and miR-214 are elevated in some cancers. Cardio-miRs and onco-miRs bear some similarities in functions and circulation profiles. miRNAs regulate WNT, FGF, Hedgehog and other signaling cascades that are involved in orchestration of embryogenesis and homeostasis as well as pathogenesis of human diseases. Because circulating miRNA profiles are modulated by genetic and environmental factors and are dysregulated by genetic and epigenetic alterations in somatic cells, circulating miRNA association studies (CMASs) within several thousands of cases each for common non-cancerous diseases and major cancers are necessary for miRNA-based diagnostics.

Staging and prognostication of multiple myeloma

Multiple myeloma (MM) is a heterogeneous disease that, over the past 15 years, has seen an increased understanding of its biology and of novel therapeutic options. Distinctive subtypes of the disease have been described, each with different outcomes and clinic-pathological features. Even though a detailed classification of MM into at least seven or eight major subtypes is possible, a more practical clinical approach can classify the disease into high-risk and non-high-risk MM. Such classification has permitted a more personalized approach to the management of the disease. Additionally, risk stratification should be included in outcome discussions with patients, as survival differs significantly by high-risk status. Nowadays, test for risk stratification are widely available and can be routinely used in the clinic. A greater understanding of the genetic abnormalities underlying the biology of MM will allow for the development of novel targeted therapies and better prognostic markers of the disease.

Serum-based miRNAs in the prediction and detection of recurrence in melanoma patients

BACKGROUND

Identification of primary melanoma patients at the highest risk of recurrence remains a critical challenge, and monitoring for recurrent disease is limited to costly imaging studies. We recently reported our array-based discovery of prognostic serum miRNAs in melanoma. In the current study, we examined the clinical utility of these serum-based miRNAs for prognosis as well as detection of melanoma recurrence.

METHODS

Serum levels of 12 miRNAs were tested using qRT-PCR at diagnosis in 283 melanoma patients (training cohort, n = 201; independent validation, n = 82; median follow-up, 68.8 months). A refined miRNA signature was chosen and evaluated. We also tested the potential clinical utility of the miRNAs in early detection and monitoring of recurrence using multiple longitudinal samples (pre- and postrecurrence) in a subset of 82 patients (n = 225). In addition, we integrated our miRNA signature with publicly available Cancer Genome Atlas data to examine the relevance of these miRNAs to melanoma biology.

RESULTS

Four miRNAs (miR-150, miR-30d, miR-15b, and miR-425) in combination with stage separated patients by recurrence-free survival (RFS) and overall survival (OS) and improved prediction of recurrence over stage alone in both the training and validation cohorts (training RFS and OS, P < .001; validation RFS, P < .001; OS, P = .005). Serum miR-15b levels significantly increased over time in recurrent patients (P < .001), adjusting for endogenous controls as well as age, sex, and initial stage. In nonrecurrent patients, miR-15b levels were not significantly changed with time (P =.17).

CONCLUSIONS

Data demonstrate that serum miRNAs can improve melanoma patient stratification over stage and support further testing of miR-15b to guide patient surveillance.

MicroRNA: important player in the pathobiology of multiple myeloma

Recent studies have revealed a pivotal role played by a class of small, noncoding RNAs, microRNA (miRNA), in multiple myeloma (MM), a plasma cell (PC) malignancy causing significant morbidity and mortality. Deregulated miRNA expression in patient's PCs and plasma has been associated with tumor progression, molecular subtypes, clinical staging, prognosis, and drug response in MM. A number of important oncogenic and tumor suppressor miRNAs have been discovered to regulate important genes and pathways such as p53 and IL6-JAK-STAT signaling. miRNAs may also form complex regulatory circuitry with genetic and epigenetic machineries, the deregulation of which could lead to malignant transformation and progression. The translational potential of miRNAs in the clinic is being increasingly recognized that they could represent novel biomarkers and therapeutic targets. This review comprehensively summarizes current progress in delineating the roles of miRNAs in MM pathobiology and management.

Epigenetic regulation of thyroid hormone receptor beta in renal cancer

Thyroid hormone receptor beta (THRB) gene is commonly deregulated in cancers and, as strengthened by animal models, postulated to play a tumor-suppressive role. Our previous studies revealed downregulation of THRB in clear cell renal cell carcinoma (ccRCC), but the culpable mechanisms have not been fully elucidated. Since epigenetic regulation is a common mechanism influencing the expression of tumor suppressors, we hypothesized that downregulation of THRB in renal cancer results from epigenetic aberrances, including CpG methylation and microRNA-dependent silencing. Our study revealed that ccRCC tumors exhibited a 56% decrease in THRB and a 37% increase in DNA methyltransferase 1 (DNMT1) expression when compared with paired non-neoplastic control samples. However, THRB CpG methylation analysis performed using BSP, SNaPshot and MSP-PCR consistently revealed no changes in methylation patterns between matched tumor and control samples. In silico analysis resulted in identification of four microRNAs (miR-155, miR-425, miR-592, and miR-599) as potentially targeting THRB transcript. Luciferase assay showed direct binding of miR-155 and miR-425 to 3′UTR of THRB, and subsequent in vivo analyses revealed that transfection of UOK171 cell line with synthetic miR-155 or miR-425 resulted in decreased expression of endogenous TRHB by 22% and 64%, respectively. Finally, real-time PCR analysis showed significant upregulation of miR-155 (354%) and miR-425 (162%) in ccRCC when compared with matched controls. Moreover, microRNA levels were negatively correlated with the amount of THRB transcript in tissue samples. We conclude that CpG methylation is not the major mechanism contributing to decreased THRB expression in ccRCC. In contrast, THRB is targeted by microRNAs miR-155 and miR-425, whose increased expression may be responsible for downregulation of THRB in ccRCC tumors.

DNA repair pathways in human multiple myeloma: role in oncogenesis and potential targets for treatment

Every day, cells are faced with thousands of DNA lesions, which have to be repaired to preserve cell survival and function. DNA repair is more or less accurate and could result in genomic instability and cancer. We review here the current knowledge of the links between molecular features, treatment, and DNA repair in multiple myeloma (MM), a disease characterized by the accumulation of malignant plasma cells producing a monoclonal immunoglobulin. Genetic instability and abnormalities are two hallmarks of MM cells and aberrant DNA repair pathways are involved in disease onset, primary translocations in MM cells, and MM progression. Two major drugs currently used to treat MM, the alkylating agent Melphalan and the proteasome inhibitor Bortezomib act directly on DNA repair pathways, which are involved in response to treatment and resistance. A better knowledge of DNA repair pathways in MM could help to target them, thus improving disease treatment.

Gene expression-based prediction of myeloma cell sensitivity to histone deacetylase inhibitors

Background:

Multiple myeloma (MM) is still a fatal plasma cell cancer. Novel compounds are currently clinically tested as a single agent in relapsing patients, but in best cases with partial response of a fraction of patients, emphasising the need to design tools predicting drug efficacy. Histone deacetylase inhibitors (HDACi) are anticancer agents targeting epigenetic regulation of gene expression and are in clinical development in MM.

Methods:

To create a score predicting HDACi efficacy, five MM cell lines were treated with trichostatin A (TSA) and gene expression profiles were determined.

Results:

The expression of 95 genes was found to be upregulated by TSA, using paired supervised analysis with Significance Analysis of Microarrays software. Thirty-seven of these 95 genes had prognostic value for overall survival in a cohort of 206 newly diagnosed MM patients and their prognostic information was summed up in a histone acetylation score (HA Score); patients with the highest HA Score had the shorter overall survival. It is worth noting that MM cell lines or patients' primary MM cells with a high HA Score had a significant higher sensitivity to TSA, valproic acid, panobinostat or vorinostat.

Conclusion:

In conclusion, the HA Score allows identification of MM patients with poor survival, who could benefit from HDACi treatment.