Therapeutic Targeting of miR-29b/HDAC4 Epigenetic Loop in Multiple Myeloma

Comprehensive analysis of microRNAs modulated by histone deacetylase inhibitors identifies microRNA-7-5p with anti-myeloma effect

Basic research to expand treatment options for multiple myeloma is greatly needed due to the refractory nature of the disease. Histone deacetylase (HDAC) inhibitors, which are epigenetic regulators, are attractive but have limited applications. MicroRNAs (miRNAs), which are also epigenetic regulators, are important molecules that may lead to future therapeutic breakthroughs. In this study, we comprehensively searched for miRNAs that are altered by HDAC inhibitors in myeloma cells. We identified miR-7-5p (miR-7) as a miRNA downregulated by HDAC inhibitors. Transfection of myeloma cell lines with miR-7 suppressed cell proliferation, induced apoptosis, and enhanced the effects of the HDAC inhibitor panobinostat. Expression of miR-7 was downregulated by c-Myc inhibition, but upregulated by bortezomib. Comprehensive examination of miR-7 targets revealed four candidates: SLC6A9, LRRC59, EXOSC2, and PSME3. Among these, we focused on PSME3, an oncogene involved in proteasome capacity in myeloma cells. PSME3 knockdown increases myeloma cell death and panobinostat sensitivity. In conclusion, miR-7, which is downregulated by HDAC inhibitors, is a tumor suppressor that targets PSME3. This miR-7 downregulation may be involved in HDAC inhibitor resistance. In addition, combinations of anti-myeloma drugs that complement changes in miRNA expression should be considered.

Non-coding RNAs and their potential exploitation in cancer therapy-related cardiotoxicity

Life expectancy in cancer patients has been extended in recent years, thanks to major breakthroughs in therapeutic developments. However, this also unmasked an increased incidence of cardiovascular diseases in cancer survivors, which is in part attributable to cancer therapy-related cardiovascular toxicity. Non-coding RNAs (ncRNAs) have received much appreciation due to their impact on gene expression. NcRNAs, which include microRNAs, long ncRNAs and circular RNAs, are non-protein-coding transcripts that are involved in the regulation of various biological processes, hence shaping cell identity and behaviour. They have also been implicated in disease development, including cardiovascular diseases, cancer and, more recently, cancer therapy-associated cardiotoxicity. This review outlines key features of cancer therapy-associated cardiotoxicity, what is known about the roles of ncRNAs in these processes and how ncRNAs could be exploited as therapeutic targets for cardioprotection.

Beneficial Effect of Olive Oil and Its Derivates: Focus on Hematological Neoplasm

Olive oil (Olea europaea) is one of the major components of the Mediterranean diet and is composed of a greater percentage of monounsaturated fatty acids, such as oleic acid; polyunsaturated fatty acids, such as linoleic acid; and minor compounds, such as phenolic compounds, and particularly hydroxytyrosol. The latter, in fact, are of greater interest since they have found widespread use in popular medicine. In recent years, it has been documented that phenolic acids and in particular hydroxytyrosol have anti-inflammatory, antioxidant, and antiproliferative action and therefore interest in their possible use in clinical practice and in particular in neoplasms, both solid and hematological, has arisen. This work aims to summarize and analyze the studies present in the literature, both in vitro and in vivo, on the possible use of minor components of olive oil in some hematological neoplasms. In recent years, in fact, interest in nutraceutical science has expanded as a possible adjuvant in the treatment of neoplastic pathologies. Although it is worth underlining that, regarding the object of our study, there are still few preclinical and clinical studies, it is, however, possible to document a role of possible interest in clinical practice.

iPSC-based modeling of preeclampsia identifies epigenetic defects in extravillous trophoblast differentiation

Preeclampsia (PE) is a hypertensive pregnancy disorder with increased risk of maternal and fetal morbidity and mortality. Abnormal extravillous trophoblast (EVT) development and function is considered to be the underlying cause of PE, but has not been previously modeled in vitro. We previously derived induced pluripotent stem cells (iPSCs) from placentas of PE patients and characterized abnormalities in formation of syncytiotrophoblast and responses to changes in oxygen tension. In this study, we converted these primed iPSC to naïve iPSC, and then derived trophoblast stem cells (TSCs) and EVT to evaluate molecular mechanisms underlying PE. We found that primed (but not naïve) iPSC-derived PE-EVT have reduced surface HLA-G, blunted invasive capacity, and altered EVT-specific gene expression. These abnormalities correlated with promoter hypermethylation of genes associated with the epithelial-mesenchymal transition pathway, specifically in primed-iPSC derived PE-EVT. Our findings indicate that abnormal epigenetic regulation might play a role in PE pathogenesis.

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.

MicroRNA-Mediated Regulation of Histone-Modifying Enzymes in Cancer: Mechanisms and Therapeutic Implications

In the past decade, significant advances in molecular research have provided a deeper understanding of the intricate regulatory mechanisms involved in carcinogenesis. MicroRNAs, short non-coding RNA sequences, exert substantial influence on gene expression by repressing translation or inducing mRNA degradation. In the context of cancer, miRNA dysregulation is prevalent and closely associated with various stages of carcinogenesis, including initiation, progression, and metastasis. One crucial aspect of the cancer phenotype is the activity of histone-modifying enzymes that govern chromatin accessibility for transcription factors, thus impacting gene expression. Recent studies have revealed that miRNAs play a significant role in modulating these histone-modifying enzymes, leading to significant implications for genes related to proliferation, differentiation, and apoptosis in cancer cells. This article provides an overview of current research on the mechanisms by which miRNAs regulate the activity of histone-modifying enzymes in the context of cancer. Both direct and indirect mechanisms through which miRNAs influence enzyme expression are discussed. Additionally, potential therapeutic implications arising from miRNA manipulation to selectively impact histone-modifying enzyme activity are presented. The insights from this analysis hold significant therapeutic promise, suggesting the utility of miRNAs as tools for the precise regulation of chromatin-related processes and gene expression. A contemporary focus on molecular regulatory mechanisms opens therapeutic pathways that can effectively influence the control of tumor cell growth and dissemination.

Hsa_circ_0000106 Acts as a Tumor Promoter in Pancreatic Cancer by Targeting the MiR-455-3p/HDAC4

Circular RNAs (circRNAs) frequently participate in pancreatic cancer (PC) progression. This study focuses on circ_0000106, a novel circRNA, and its potential function in PC development. Circ_00001106, miR-455-3p, and HDAC4 expression levels in PC were determined using qRT-PCR and immunoblotting. RNA immunoprecipitation and dual-luciferase reporter assays were performed to verify their binding interactions. Loss-of-function assays, including CCK-8, colony formation, and transwell assays, were used to estimate the proliferative and migratory properties of PC cells. A nude mouse model was constructed to assess the influence of circ_0000106 on tumor formation in vivo. A pronounced elevation of circ_0000106 and HDAC4 and a reduction of miR-455-3p in PC were observed. Circ_0000106 was prone to binding to miR-455-3p, and miR-455-3p further targeted HDAC4. Functionally, the proliferative and migratory properties of PC cells were dampened by the loss of circ_0000106 or HDAC4 and could be potentiated by miR-455-3p inhibition. Moreover, the knockdown of circ_0000106 delayed tumor growth in vivo. Additionally, the downregulation of miR-455-3p attenuated the repressive effects of circ_0000106 deficiency on PC cell migration and proliferation. Loss of HDAC4 exerted similar mitigative effects on miR-455-3p downregulation-stimulated PC cells. In conclusion, circ_0000106 promotes tumor migration and growth in PC by targeting the miR-455-3p/HDAC4 axis. These results suggest that the circ_0000106/miR-455-3p/HDAC4 network could be regarded as a latent target for PC treatment.

Identification of HDAC4 as a potential therapeutic target and prognostic biomarker for ZFTA-fused ependymomas

Members of the HDAC family are predictive biomarkers and regulate the tumorigenesis in several cancers. However, the role of these genes in the biology of intracranial ependymomas (EPNs) remains unexplored. Here, an analysis of eighteen HDACs genes in an EPN transcriptomic dataset, revealed significantly higher levels of HDAC4 in supratentorial ZFTA fusion (ST-ZFTA) compared with ST-YAP1 fusion and posterior fossa EPNs, while HDAC7 and SIRT2 were downregulated in ST-ZFTA. HDAC4 was also overexpressed in ST-ZFTA as measured by single-cell RNA-Seq, quantitative real time-polymerase chain reaction, and immunohistochemistry. Survival analyses showed a significantly worse outcome for EPNs with higher HDAC4 and SIRT1 mRNA levels. Ontology enrichment analysis showed an HDAC4-high signature consistent with viral processes while collagen-containing extracellular matrix and cell-cell junction were enriched in those with an HDAC4-low signature. Immune gene analysis demonstrated a correlation between HDAC4 expression and low levels of NK resting cells. Several small molecules compounds targeting HDAC4 and ABCG2, were predicted by in silico analysis to be effective against HDAC4-high ZFTA. Our results provide novel insights into the biology of the HDAC family in intracranial ependymomas and reveal HDAC4 as a prognostic marker and potential therapeutic target in ST-ZFTA.

Regulation of miRNA expression by α4β1 integrin-dependent multiple myeloma cell adhesion

The α4β1 integrin regulates the trafficking of multiple myeloma (MM) cells and contributes to MM disease progression. MicroRNAs (miRNAs) can have both tumor suppressor and oncogenic roles and thus are key controllers of tumor evolution, and have been associated with different phases of MM pathogenesis. Using small RNAseq analysis, we show here that α4β1-dependent MM cell adhesion regulates the expression of forty different miRNAs, therefore expanding our current view of the α4β1 involvement in MM cell biology. Specific upregulation of miR-324-5p and miR-331-3p in cells attached to α4β1 ligands was confirmed upon silencing the α4 integrin subunit, and their increased levels found to be dependent on Erk1/2- and PI3K-Akt-, but not Src-dependent signaling. Enhanced miR-324-5p expression upon α4β1-mediated MM cell adhesion aimed the hedgehog (Hh) component SMO, revealing that the miR-324-5p-SMO module represents a α4β1-regulated pathway that could control Hh-dependent cellular responses in myeloma. Our results open new therapy research avenues around the α4β1 contribution to MM progression that deserve to be investigated.

Decoding the role of miRNAs in multiple myeloma pathogenesis: A focus on signaling pathways

Multiple myeloma (MM) is a cancer of plasma cells that has been extensively studied in recent years, with researchers increasingly focusing on the role of microRNAs (miRNAs) in regulating gene expression in MM. Several non-coding RNAs have been demonstrated to regulate MM pathogenesis signaling pathways. These pathways might regulate MM development, apoptosis, progression, and therapeutic outcomes. They are Wnt/β-catenin, PI3K/Akt/mTOR, P53 and KRAS. This review highlights the impending role of miRNAs in MM signaling and their relationship with MM therapeutic interventions.

Exosomal miRNAs in the Tumor Microenvironment of Multiple Myeloma

Multiple myeloma (MM) is a malignancy of plasma cells in the bone marrow and is characterized by the clonal proliferation of B-cells producing defective monoclonal immunoglobulins. Despite the latest developments in treatment, drug resistance remains one of the major challenges in the therapy of MM. The crosstalk between MM cells and other components within the bone marrow microenvironment (BME) is the major determinant of disease phenotypes. Exosomes have emerged as the critical drivers of this crosstalk by allowing the delivery of informational cargo comprising multiple components from miniature peptides to nucleic acids. Such material transfers have now been shown to perpetuate drug-resistance development and disease progression in MM. MicroRNAs(miRNAs) specifically play a crucial role in this communication considering their small size that allows them to be readily packed within the exosomes and widespread potency that impacts the developmental trajectory of the disease inside the tumor microenvironment (TME). In this review, we aim to provide an overview of the current understanding of the role of exosomal miRNAs in the epigenetic modifications inside the TME and its pathogenic influence on the developmental phenotypes and prognosis of MM.

Thymoquinone, piperine, and sorafenib combinations attenuate liver and breast cancers progression: epigenetic and molecular docking approaches

BACKGROUND

Traditional herbal medicine has been used for centuries to cure many pathological disorders, including cancer. Thymoquinone (TQ) and piperine (PIP) are major bioactive constituents of the black seed (Nigella sativa) and black pepper (Piper nigrum), respectively. The current study aimed to explore the potential chemo-modulatory effects, mechanisms of action, molecular targets, and binding interactions after TQ and PIP treatments and their combination with sorafenib (SOR) against human triple-negative breast cancer (MDA-MB-231) and liver cancer (HepG2) cells.

METHODS

We determined drug cytotoxicity by MTT assay, cell cycle, and death mechanism by flow cytometry. Besides, the potential effect of TQ, PIP, and SOR treatment on genome methylation and acetylation by determination of DNA methyltransferase (DNMT3B), histone deacetylase (HDAC3) and miRNA-29c expression levels. Finally, a molecular docking study was performed to propose potential mechanisms of action and binding affinity of TQ, PIP, and SOR with DNMT3B and HDAC3.

RESULTS

Collectively, our data show that combinations of TQ and/or PIP with SOR have significantly enhanced the SOR anti-proliferative and cytotoxic effects depending on the dose and cell line by enhancing G2/M phase arrest, inducing apoptosis, downregulation of DNMT3B and HDAC3 expression and upregulation of the tumor suppressor, miRNA-29c. Finally, the molecular docking study has identified strong interactions between SOR, PIP, and TQ with DNMT3B and HDAC3, inhibiting their normal oncogenic activities and leading to growth arrest and cell death.

CONCLUSION

This study reported TQ and PIP as enhancers of the antiproliferative and cytotoxic effects of SOR and addressed the mechanisms, and identified molecular targets involved in their action.

HDAC4 in cancer: A multitasking platform to drive not only epigenetic modifications

Controlling access to genomic information and maintaining its stability are key aspects of cell life. Histone acetylation is a reversible epigenetic modification that allows access to DNA and the assembly of protein complexes that regulate mainly transcription but also other activities. Enzymes known as histone deacetylases (HDACs) are involved in the removal of the acetyl-group or in some cases of small hydrophobic moieties from histones but also from the non-histone substrate. The main achievement of HDACs on histones is to repress transcription and promote the formation of more compact chromatin. There are 18 different HDACs encoded in the human genome. Here we will discuss HDAC4, a member of the class IIa family, and its possible contribution to cancer development.

miRNAs and Multiple Myeloma: Focus on the Pathogenesis, Prognosis, and Drug Resistance

Multiple myeloma (MM) produces clonal plasma cells and aberrant monoclonal antibody accumulation in patients' bone marrow (BM). Around 1% of all cancers and 13% of hematological malignancies are caused by MM, making it one of the most common types of cancer. Diagnostic and therapeutic methods for managing MM are currently undergoing extensive research. MicroRNAs (miRNAs) are short noncoding RNAs that reduce or inhibit the translation of their target mRNA after transcription. Because miRNAs play an influential role in how myeloma develops, resources, and becomes resistant to drugs, miRNA signatures may be used to diagnose, do prognosis, and treat the myeloma response. Consequently, researchers have investigated the levels of miRNA in plasma cells from MM patients and developed tools to test whether they directly impacted tumor growth. This review discusses the latest discoveries in miRNA science and their role in the development of MM. We also emphasize the potential applications of miRNAs to diagnose, prognosticate, and treat MM in the future.

Potential epigenetic molecular regulatory networks in ocular neovascularization

Neovascularization is one of the many manifestations of ocular diseases, including corneal injury and vascular diseases of the retina and choroid. Although anti-VEGF drugs have been used to effectively treat neovascularization, long-term use of anti-angiogenic factors can cause a variety of neurological and developmental side effects. As a result, better drugs to treat ocular neovascularization are urgently required. There is mounting evidence that epigenetic regulation is important in ocular neovascularization. DNA methylation and histone modification, non-coding RNA, and mRNA modification are all examples of epigenetic mechanisms. In order to shed new light on epigenetic therapeutics in ocular neovascularization, this review focuses on recent advances in the epigenetic control of ocular neovascularization as well as discusses these new mechanisms.

The Role of miR-29s in Human Cancers—An Update

MicroRNAs (miRNAs) are small non-coding RNAs that directly bind to the 3’ untranslated region (3’-UTR) of the target mRNAs to inhibit their expression. The miRNA-29s (miR-29s) are suggested to be either tumor suppressors or oncogenic miRNAs that are strongly dysregulated in various types of cancer. Their dysregulation alters the expression of their target genes, thereby exerting influence on different cellular pathways including cell proliferation, apoptosis, migration, and invasion, thereby contributing to carcinogenesis. In the present review, we aimed to provide an overview of the current knowledge on the miR-29s biological network and its functions in cancer, as well as its current and potential applications as a diagnostic and prognostic biomarker and/or a therapeutic target in major types of human cancer.

Role of microRNAs in B-Cell Compartment: Development, Proliferation and Hematological Diseases

B-cell development is a very orchestrated pathway that involves several molecules, such as transcription factors, cytokines, microRNAs, and also different cells. All these components maintain the ideal microenvironment and control B-cell differentiation. MicroRNAs are small non-coding RNAs that bind to target mRNA to control gene expression. These molecules could circulate in the body in a free form, protein-bounded, or encapsulated into extracellular vesicles, such as exosomes. The comprehension of the role of microRNAs in the B-cell development was possible based on microRNA profile of each B-cell stage and functional studies. Herein, we report the knowledge about microRNAs in the B-cell the differentiation, proliferation, and also in hematological malignancies.

Deacetylation of Glutaminase by HDAC4 contributes to Lung Cancer Tumorigenesis

Inhibiting cancer metabolism via glutaminase (GAC) is a promising strategy to disrupt tumor progression. However, mechanism regarding GAC acetylation remains mostly unknown. In this study, we demonstrate that lysine acetylation is a vital post-translational modification that inhibits GAC activity in non-small cell lung cancer (NSCLC). We identify that Lys311 is the key acetylation site on GAC, which is deacetylated by HDAC4, a class II deacetylase. Lys311 acetylation stimulates the interaction between GAC and TRIM21, an E3 ubiquitin ligase of the tripartite motif (TRIM) family, therefore promoting GAC K63-linked ubiquitination and inhibiting GAC activity. Furthermore, GAC^K311Q mutation in A549 cells decreases cell proliferation and alleviates tumor malignancy. Our findings reveal a novel mechanism of GAC regulation by acetylation and ubiquitination that participates in non-small cell lung cancer tumorigenesis.

Pharmacological and Genetic Inhibition of HDAC4 Alleviates Renal Injury and Fibrosis in Mice

Histone deacetylase 4 (HDAC4) has been shown to be involved in cell proliferation, differentiation, and migration and is associated with a variety of cancers. However, the role of HDAC4 in renal fibrogenesis and its mechanisms are unclear. We assessed the role of HDAC4 and possible mechanisms of fibrosis in a murine model of kidney injury induced by unilateral ureteral obstruction (UUO) using tasquinimod, a highly selective HDAC4 inhibitor, and knockout mice with depletion of HDAC4 in renal tubular cells. UUO injury resulted in increased expression of HDAC4 and fibrotic proteins fibronectin and α-smooth muscle actin, while treatment with tasquinimod or knockout of HDAC4 significantly reduced their expression. Pharmacological and genetic inhibition of HDAC4 also decreased tubular epithelial cell arrest in the G2/M phase of the cell cycle, expression of transforming growth factor-β1 and phosphorylation of Smad3, signal transducer and activator of transcription 3, and extracellular signal-regulated kinase 1/2 in the injured kidney. Moreover, tasquinimod treatment or HDAC4 deletion inhibited UUO-induced renal tubular cell injury and apoptosis as indicated by reduced expression of neutrophil gelatinase-associated lipocalin, Bax, and inhibition of caspase-3. Finally, administration of tasquinimod or knockdown of HDAC4 prevented injury-related repression of Klotho, a renoprotective protein. Our results indicate that HDAC4 is critically involved in renal tubular injury and fibrosis and suggest that HDAC4 is a potential therapeutic target for treatment of chronic fibrotic kidney disease.

The Multiple Myeloma Landscape: Epigenetics and Non-Coding RNAs

Simple Summary

Recent findings in multiple myeloma have led to therapies which have improved patient life quality and expectancy. However, frequent relapse and drug resistance emphasize the need for more efficient therapeutic approaches. The discovery of non-coding RNAs as key actors in multiple myeloma has broadened the molecular landscape of this disease, together with classical epigenetic factors such as methylation and acetylation. microRNAs and long non-coding RNAs comprise the majority of the described non-coding RNAs dysregulated in multiple myeloma, while circular RNAs are recently emerging as promising molecular targets. This review provides a comprehensive overview of the most recent knowledge on this topic and suggests new therapeutic strategies.

Abstract

Despite advances in available treatments, multiple myeloma (MM) remains an incurable disease and represents a challenge in oncohematology. New insights into epigenetic factors contributing to MM development and progression have improved the knowledge surrounding its molecular basis. Beyond classical epigenetic factors, including methylation and acetylation, recent genome analyses have unveiled the importance of non-coding RNAs in MM pathogenesis. Non-coding RNAs have become of interest, as their dysregulation opens the door to new therapeutic approaches. The discovery, in the past years, of molecular techniques, such as CRISPR-Cas, has led to innovative therapies with potential benefits to achieve a better outcome for MM patients. This review summarizes the current knowledge on epigenetics and non-coding RNAs in MM pathogenesis.

CircRIMKLB promotes myoblast proliferation and inhibits differentiation by sponging miR-29c to release KCNJ12

Muscle development is a complex process that was regulated by many factors, among which non-coding RNAs (ncRNAs) play a vital role in regulating multiple life activities of muscle cells. Circular RNA (circRNA), a type of non-coding RNA with closed-loop structure, has been reported to affect multiple life processes. However, the roles of circRNAs on muscle development have not been fully elucidated. The present study aimed to determine whether and how circRIMKLB affects muscle development. Our study revealed that circRIMKLB promoted myoblast proliferation and inhibited differentiation. Besides, miR-29c was proved as a downstream target of circRIMKLB using dual-luciferase reporter assay and RNA-binding protein immunoprecipitation (RIP) assay. Also, potassium inwardly rectifying channel subfamily J member 12 (KCNJ12) was identified as a novel target of miR-29c via dual-luciferase reporter assay, quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR), and western blot. CircRIMKLB and KCNJ12 were both proved to regulate cell cycle on muscle regeneration after injury in vivo. In conclusion, we demonstrated that circRIMKLB sponged miR-29c, releasing KCNJ12 to regulate myoblast proliferation and differentiation and regulating cell cycle during muscle regeneration after injury in vivo.

HDAC7 promotes NSCLC proliferation and metastasis via stabilization by deubiquitinase USP10 and activation of β-catenin-FGF18 pathway

Background

Histone deacetylases (HDACs) play crucial roles in cancers, but the role and mechanism of HDAC7 in NSCLC have not been fully understood.

Methods

A total of 319 patients with non-small cell lung cancer (NSCLC) who underwent surgery were enrolled in this study. Immunohistochemistry and Kaplan–Meier survival analysis were performed to investigate the relationship between HDAC7, fibroblast growth factor 18 (FGF18) expression, and clinicopathologic characteristics. Cell functional experiments were implemented both in vivo and in vitro to investigate the effects on NSCLC cell proliferation and metastasis. Recombinant lentivirus–meditated in vivo gene overexpression or knockdown, real-time polymerase chain reaction (PCR), western blotting, and coimmunoprecipitation assays were applied to clarify the underlying molecular mechanism of HDAC7 in promoting NSCLC progression.

Results

The elevated expression of HDAC7 or FGF18 was positively correlated with poor prognosis, tumor–node–metastasis (TNM) stage, and tumor differentiation of NSCLC patients. NSCLC patients with co-expressed HDAC7 and FGF18 suffered the worst prognosis. HDAC7 overexpression promoted NSCLC proliferation and metastasis by upregulating FGF18. Conversely, overexpression of FGF18 reversed the attenuated ability in tumor growth and metastasis mediated by downregulating HDAC7. In terms of mechanism, our results suggested that the interaction of HDAC7 with β-catenin caused decreased β-catenin acetylation level at Lys49 and decreased phosphorylation level at Ser45. As a consequence, the HDAC7-mediated posttranslational modification of β-catenin facilitated nuclear transfer and activated FGF18 expression via binding to TCF4. Furthermore, deubiquitinase USP10 interacted with and stabilized HDAC7. The suppression of USP10 significantly accelerated the degradation of HDAC7 and weakened NSCLC growth and migration.

Conclusions

Our findings reveal that HDAC7 promotes NSCLC progression through being stabilized by USP10 and activating the β-catenin-FGF18 pathway. Targeting this novel pathway may be a promising strategy for further developments in NSCLC therapy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-022-02266-9.

Vorinostat triggers miR-769-5p/3p-mediated suppression of proliferation and induces apoptosis via the STAT3-IGF1R-HDAC3 complex in human gastric cancer

Previous reports have shown that histone deacetylase inhibitors (HDACi) can alter miRNA expression in a range of cancers. Both the 5p-arm and 3p-arm of mature miRNAs can be expressed from the same precursor and involved in cancer progress. Nevertheless, the detailed mechanism by which vorinostat (SAHA), a HDACi, triggers miR-769-5p/miR-769-3p-mediated suppression of proliferation and induces apoptosis in gastric cancer (GC) cells remains elusive. Here, we showed that the miRNA-seq analysis of GC cells treated with SAHA identified seven differentially expressed miRNAs with both strands of the miRNA duplex. miR-769-5p/miR-769-3p expression was downregulated in GC tissues compared with normal tissues. Functionally, high expression of miR-769-5p/miR-769-3p blocked the malignant abilities of GC cells. Mechanistically, miR-769-5p/miR-769-3p targeted IGF1R and IGF1R overexpression rescued the effects of miR-769-5p/miR-769-3p on GC cells growth and metastasis. Moreover, STAT3 bound to the promoter of miR-769. Furthermore, miR-769-5p/miR-769-3p expression was negatively regulated by the STAT3-IGF1R-HDAC3 complex. Besides, miR-769-5p/miR-769-3p synergized with SAHA to promote GC cells apoptosis. Our studies suggest that miR-769-5p/miR-769-3p acts as a tumor suppressor by the STAT3-IGF1R-HDAC3 complex. Moreover, SAHA triggers miR-769-5p/miR-769-3p-mediated inhibition of proliferation and induces apoptosis in GC cells.

lncRNA MSTRG.29039.1 Promotes Proliferation by Sponging hsa-miR-12119 via JAK2/STAT3 Pathway in Multiple Myeloma

Noncoding RNA (ncRNA) is involved in the occurrence, development, metastasis, and drug resistance of tumors and involves a variety of biological functions. In addition, miRNA can regulate proliferation and migration and even regulate epigenetics to promote the development of multiple myeloma (MM). However, the mechanism of ncRNA involved in MM is still unclear, and there are many unknown ncRNAs to be explored. This research is aimed at discovering the unknown lncRNA in MM through high-throughput sequencing and to study the mechanism and role of competitive endogenous RNA (ceRNA) involved in the pathogenesis of MM for the development of novel molecular markers and potential new targeted drugs. We screened out 262 new lncRNAs with statistical differences by RNA sequencing and selected the lncRNA MSTRG.29039.1 according to the expression and function of lncRNAs and their target genes in MM. We verified that MSTRG.29039.1 and its target gene OSMR were highly expressed in MM. After knockdown of MSTRG.29039.1 in MM cell lines, the expression of OSMR was decreased, and the expression of hsa-miR-12119 was upregulated which can also promote cell apoptosis and inhibit proliferation. Then, we knocked down hsa-miR-12119 and MSTRG.29039.1, we found that apoptosis of MM cells was reduced, and cell proliferation was increased compared with just knocking down hsa-miR-12119. We further verified the direct binding relationship between MSTRG.29039.1 and OSMR by the dual-luciferase reporter assay system. Thus, MSTRG.29039.1 can competitively bind with miRNA to counteract the inhibitory effect of miRNA on OSMR, which regulates cell proliferation and apoptosis through the JAK2/STAT3 pathway. In a conclusion, lncRNA MSTRG.29039.1 could promote proliferation by sponging hsa-miR-12119 via the JAK2/STAT3 pathway in multiple myeloma. This may be a molecular marker and a potential therapeutic target for MM.

miR-17-3p promotes the proliferation of multiple myeloma cells by downregulating P21 expression through LMLN inhibition

Multiple myeloma (MM), a hematological malignancy, has a poor prognosis and requires an invasive procedure. Reports have implicated miRNAs in the diagnosis, treatment and prognosis of hematological malignancies. In our study, we evaluated the expression profiles of miR-17-3p in plasma and bone marrow mononuclear cells of monoclonal gammopathy of undetermined significance (MGUS) and MM patients and healthy subjects. The results showed that the plasma and mononuclear cell expression levels of miR-17-3p in MM patients were higher than those in MGUS patients and normal controls. In addition, the expression of miR-17-3p was positively correlated with diagnostic indexes, such as marrow plasma cell abundance and serum M protein level, and positively correlated with the International Staging System stage of the disease. Receiver operating characteristic curve analysis suggested that miR-17-3p might be a diagnostic index of MM. Moreover, miR-17-3p regulated cell proliferation, apoptosis and the cell cycle through P21 in MM cell lines and promoted MM tumor growth in vivo. Furthermore, we predicted and verified LMLN as a functional downstream target gene of miR-17-3p. Negatively regulated by miR-17-3p, LMLN inhibits MM cell growth, exerting a tumor suppressive function through P21. Taken together, our data identify miR-17-3p as a promising diagnostic biomarker for MM in the clinic and unveil a new miR-17-3p-LMLN-P21 axis in MM progression.

Genomic Instability in Multiple Myeloma: A "Non-Coding RNA" Perspective

Simple Summary

Genomic instability (GI) plays an important role in the pathobiology of multiple myeloma (MM) by promoting the acquisition of several tumor hallmarks. Molecular determinants of GI in MM are continuously emerging and will be herein discussed, with specific regard to non-coding RNAs. Targeting non-coding RNA molecules known to be involved in GI indeed provides novel routes to dampen such oncogenic mechanisms in MM.

Abstract

Multiple myeloma (MM) is a complex hematological malignancy characterized by abnormal proliferation of malignant plasma cells (PCs) within a permissive bone marrow microenvironment. The pathogenesis of MM is unequivocally linked to the acquisition of genomic instability (GI), which indicates the tendency of tumor cells to accumulate a wide repertoire of genetic alterations. Such alterations can even be detected at the premalignant stages of monoclonal gammopathy of undetermined significance (MGUS) and smoldering multiple myeloma (SMM) and, overall, contribute to the acquisition of the malignant traits underlying disease progression. The molecular basis of GI remains unclear, with replication stress and deregulation of DNA damage repair pathways representing the most documented mechanisms. The discovery that non-coding RNA molecules are deeply dysregulated in MM and can target pivotal components of GI pathways has introduced a further layer of complexity to the GI scenario in this disease. In this review, we will summarize available information on the molecular determinants of GI in MM, focusing on the role of non-coding RNAs as novel means to tackle GI for therapeutic intervention.

Epigenetic Regulation of MicroRNA Clusters and Families during Tumor Development

MicroRNAs are small non-coding single-stranded RNA molecules regulating gene expression on a post-transcriptional level based on the seed sequence similarity. They are frequently clustered; thus, they are either simultaneously transcribed into a single polycistronic transcript or they may be transcribed independently. Importantly, microRNA families that contain the same seed region and thus target related signaling proteins, may be localized in one or more clusters, which are in a close relationship. MicroRNAs are involved in basic physiological processes, and their deregulation is associated with the origin of various pathologies, including solid tumors or hematologic malignancies. Recently, the interplay between the expression of microRNA clusters and families and epigenetic machinery was described, indicating aberrant DNA methylation or histone modifications as major mechanisms responsible for microRNA deregulation during cancerogenesis. In this review, the most studied microRNA clusters and families affected by hyper- or hypomethylation as well as by histone modifications are presented with the focus on particular mechanisms. Finally, the diagnostic and prognostic potential of microRNA clusters and families is discussed together with technologies currently used for epigenetic-based cancer therapies.

HDAC4 promotes nasopharyngeal carcinoma progression and serves as a therapeutic target

Histone deacetylases (HDACs) are involved in tumor progression, and some have been successfully targeted for cancer therapy. The expression of histone deacetylase 4 (HDAC4), a class IIa HDAC, was upregulated in our previous microarray screen. However, the role of HDAC4 dysregulation and mechanisms underlying tumor growth and metastasis in nasopharyngeal carcinoma (NPC) remain elusive. Here, we first confirmed that the HDAC4 levels in primary and metastatic NPC tissues were significantly increased compared with those in normal nasopharyngeal epithelial tissues and found that high HDAC4 expression predicted a poor overall survival (OS) and progression-free survival (PFS). Functionally, HDAC4 accelerated cell cycle G1/S transition and induced the epithelial-to-mesenchymal transition to promote NPC cell proliferation, migration, and invasion in vitro, as well as tumor growth and lung metastasis in vivo. Intriguingly, knockdown of N-CoR abolished the effects of HDAC4 on the invasion and migration abilities of NPC cells. Mechanistically, HDAC3/4 binds to the E-cadherin promoter to repress E-cadherin transcription. We also showed that the HDAC4 inhibitor tasquinimod suppresses tumor growth in NPC. Thus, HDAC4 may be a potential diagnostic marker and therapeutic target in patients with NPC.

Lnc NEAT1/miR-29b-3p/Sp1 form a positive feedback loop and modulate bortezomib resistance in human multiple myeloma cells

The overall survival of multiple myeloma (MM) patients significantly improved with the use of proteasome inhibitor such as bortezomib. However, resistance to sorafenib limits its use. Bortezomib-resistant MM cells were generated and their bortezomib-resistant properties were confirmed by cell viability and apoptosis assays. To explore functions and underlying mechanisms of long non-coding RNA nuclear paraspeckle assembly transcript 1 (NEAT1) on bortezomib resistance in MM, MTT assays, flow cytometry analyses, dual luciferase report gene assays, RNA pulldown assays and chromatin immunoprecipitation assays were carried out. NEAT1 and specific protein 1 (Sp1) was upregulated while miR-29b-3p was down regulated in bortezomib-resistant MM cells. NEAT1 promoted Sp1 expression by sponging miR-29b-3p and then enhanced the tolerance of MM cells to bortezomib. Sp1 targeted to NEAT1 promoter region promoting NEAT1 transcription and formed a positive feedback loop. NEAT1 and Sp1 levels were higher and miR-29b-3p was levels were lower in bortezomib-resistant MM patients. NEAT1/miR-29b-3p/Sp1 feedback loop enhanced the tolerance of MM cells to bortezomib. These results indicate potentially valuable targets for overcoming bortezomib resistance for MM.

Epigenetic Aberrations in Multiple Myeloma

Simple Summary

Multiple Myeloma (MM) is a blood cancer characterized by an uncontrolled growth of cells named plasma cells, within the bone marrow. Patients with MM may present with anemia, bone lesions and kidney impairment. Several studies have been performed in order to provide an explanation to how this tumor may develop. Among them, the so called “epigenetic modifications” certainly represent important players that have been shown to support MM development and disease progression. The present article aims to summarize the current knowledge in the specific are of “epigenetics” in MM.

Abstract

Multiple myeloma (MM) is a plasma cell dyscrasia characterized by proliferation of clonal plasma cells within the bone marrow. Several advances in defining key processes responsible for MM pathogenesis and disease progression have been made; and dysregulation of epigenetics, including DNA methylation and histone modification, has emerged as a crucial regulator of MM pathogenesis. In the present review article, we will focus on the role of epigenetic modifications within the specific context of MM.

Role of microRNAs in Diagnosis, Prognosis and Management of Multiple Myeloma

Multiple myeloma (MM) is a cancerous bone disease characterized by malignant transformation of plasma cells in the bone marrow. MM is considered to be the second most common blood malignancy, with 20,000 new cases reported every year in the USA. Extensive research is currently enduring to validate diagnostic and therapeutic means to manage MM. microRNAs (miRNAs) were shown to be dysregulated in MM cases and to have a potential role in either progression or suppression of MM. Therefore, researchers investigated miRNAs levels in MM plasma cells and created tools to test their impact on tumor growth. In the present review, we discuss the most recently discovered miRNAs and their regulation in MM. Furthermore, we emphasized utilizing miRNAs as potential targets in the diagnosis, prognosis and treatment of MM, which can be useful for future clinical management.

Multiple myeloma: the (r)evolution of current therapy and a glance into future

Over the past 20 years, the regulatory approval of several novel agents to treat multiple myeloma (MM) has prolonged median patient survival from 3 to 8-10 years. Increased understanding of MM biology has translated to advances in diagnosis, prognosis, and response assessment, as well as informed the development of targeted and immune agents. Here we provide an overview of the recent progress in MM, and highlight research areas of greatest promise to further improve patient outcome in the future.

Non-Coding RNAs in Multiple Myeloma Bone Disease Pathophysiology

Bone remodeling is uncoupled in the multiple myeloma (MM) bone marrow niche, resulting in enhanced osteoclastogenesis responsible of MM-related bone disease (MMBD). Several studies have disclosed the mechanisms underlying increased osteoclast formation and activity triggered by the various cellular components of the MM bone marrow microenvironment, leading to the identification of novel targets for therapeutic intervention. In this regard, recent attention has been given to non-coding RNA (ncRNA) molecules, that finely tune gene expression programs involved in bone homeostasis both in physiological and pathological settings. In this review, we will analyze major signaling pathways involved in MMBD pathophysiology, and report emerging evidence of their regulation by different classes of ncRNAs.

HDAC4 Knockdown Induces Preeclampsia Cell Autophagy and Apoptosis by miR-29b

Preeclampsia (PE) is one of the main causes of maternal death and perinatal morbidity and mortality. Considering that histone deacetylase 4 (HDAC4) activity could relate to trophoblast cell motility and be antagonized by miR-29b, the aim of the present study was to investigate the ability of HDAC4 to regulate placental trophoblast cells by miR-29b. We assessed the cytological changes of PE patients, and the expression and cellular localization of HDAC4 and LC3 by histological analysis, immunohistochemistry, western blot assay, and immunofluorescence staining assay. We observed the effect of hypoxia on HDAC4, the correction of HDAC4/miR-29b, and the effects of HDAC4/miR-29b on HTR8 cells by dual-luciferase, quantitative real-time PCR, western blot assay, and flow cytometry assay. Here, we first found that HDAC4 was lowly expressed in PE tissues, while LC3 was highly expressed. In addition, the expression of HDAC4 was inhibited by hypoxia in HTR8 cells. Furthermore, our data showed that HDAC4 activity could be antagonized by miR-29b. We highlighted that miR-29b specifically targeted HDAC4 in trophoblast cells and both molecules were involved in a functional loop. Altogether, our findings demonstrated that silencing of HDAC4 could trigger cell autophagy and apoptosis directly by miR-29b in placental trophoblast cells of PE.

Identification of MicroRNAs With In Vivo Efficacy in Multiple Myeloma-related Xenograft Models

BACKGROUND/AIM

Multiple myeloma is a B-cell neoplasm, which can spread within the marrow of the bones forming many small tumors. In advanced disease, multiple myeloma can spread to the blood as plasma cell leukemia. In some cases, a localized tumor known as plasmacytoma is found within a single bone. Despite the approval of several agents such as melphalan, corticosteroids, proteasome inhibitors, thalidomide-based immuno-modulatory agents, histone deacetylase inhibitors, a nuclear export inhibitor and monoclonal antibodies daratuzumab and elatuzumab, the disease presently remains uncurable.

MATERIALS AND METHODS

In order to define new targets and treatment modalities we searched the literature for microRNAs, which increase or inhibit in vivo efficacy in multiple-myeloma-related xenograft models.

RESULTS AND CONCLUSION

We identified six up-regulated and twelve down-regulated miRs, which deserve further preclinical validation.

MicroRNAs-Based Nano-Strategies as New Therapeutic Approach in Multiple Myeloma to Overcome Disease Progression and Drug Resistance

MicroRNAs (miRNAs, or miRs) are single-strand short non-coding RNAs with a pivotal role in the regulation of physiological- or disease-associated cellular processes. They bind to target miRs modulating gene expression at post-transcriptional levels. Here, we present an overview of miRs deregulation in the pathogenesis of multiple myeloma (MM), and discuss the potential use of miRs/nanocarriers association in clinic. Since miRs can act as oncogenes or tumor suppressors, strategies based on their inhibition and/or replacement represent the new opportunities in cancer therapy. The miRs delivery systems include liposomes, polymers, and exosomes that increase their physical stability and prevent nuclease degradation. Phase I/II clinical trials support the importance of miRs as an innovative therapeutic approach in nanomedicine to prevent cancer progression and drug resistance. Results in clinical practice are promising.

Roles of noncoding RNAs in drug resistance in multiple myeloma

Despite the administration of new effective drugs in recent years, relapse and drug resistance are still the main obstacles in multiple myeloma (MM) treatment, making MM an incurable disease. To overcome drug resistance in MM, it is critical to understand the underlying mechanisms of malfunctioning gene expression and develop novel targeted therapies. During the past few decades, with the discovery and characterization of noncoding RNAs (ncRNAs), the landscape of dysregulated ncRNAs of cancers as well as their biological and pathobiological functions in tumorigenesis and drug resistance have been recognized. Studies about ncRNAs improved the understanding of variations of drug response among individuals at a level distinguished from genetic polymorphism, and provided with new orientations for targeted therapies. In this review, we will summarize the emerging impact and underlying molecular mechanisms of the most relevant classes of ncRNAs in drug resistance of MM, and discuss the potential as well as strategies of treating ncRNAs as therapeutic targets.

MIR145-3p promotes autophagy and enhances bortezomib sensitivity in multiple myeloma by targeting HDAC4

Multiple myeloma (MM) is an incurable plasma cell malignancy with poor survival. Autophagy, a stress-responsive catabolic process mediated by lysosomal activity, plays a crucial role in the pathophysiology of MM. Growing evidence has indicated that dysregulated microRNAs (miRNAs) are associated with the aberrant autophagy in various human cancers. However, to date, few miRNAs have been reported to directly modulate autophagy in the pathobiology of MM. In this study, we investigated the role of MIR145-3p (microRNA 145-3p) in MM, with focus on cellular processes autophagy and cell death. Our results provided evidence that downregulation of MIR145-3p expression was associated with disease progression in human MM. MIR145-3p triggered autophagic flux through direct targeting of HDAC4 (histone deacetylase 4) in MM cells, leading to enhanced apoptosis. Silencing HDAC4 recapitulated the effects of MIR145-3p, whereas enforced expression of HDAC4 abrogated the effects of MIR145-3p. Furthermore, we showed that suppression of HDAC4 by MIR145-3p resulted in upregulation of the pro-apoptotic protein BCL2L11 and caused MTORC1 inactivation, which in turn led to enhanced autophagy and cell death. Importantly, we demonstrated that MIR145-3p mimic could potentiate the anti-MM activity of bortezomib in both in vitro and in vivo experiments. Overall, our findings indicate that MIR145-3p exerted a tumor suppression function in MM by inducing autophagic cell death and suggest that MIR145-3p-based targeted therapy would represent a novel strategy for MM treatment.Abbreviations: 3-MA: 3-methyladenine; 3'-UTR: 3'-untranslated region; 7-AAD: 7-aminoactinomycin D; ACTB: actin beta; ANXA5: annexin A5; ATG5: autophagy related 5; ATG7: autophagy related 7; B2M: beta-2-microglobulin; BAF: bafilomycin A1; BCL2L11: BCL2 like 11; Bort: bortezomib; CASP3: caspase 3; CCK-8: Cell Counting Kit-8; CQ: chloroquine; Ct: threshold cycle; ctrl: control; DAPI: 4',6-diamidino-2-phenylindole; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; GFP: green fluorescent protein; HDAC4: histone deacetylase 4; ISS: International Staging System; MAP1LC3B: microtubule associated protein 1 light chain 3 beta; miRNAs: microRNAs; MIR145-3p: microRNA 145-3p; MM: multiple myeloma; mRNA: messenger RNA; MTOR: mechanistic target of rapamycin kinase; MTORC1: mechanistic target of rapamycin kinase complex 1; PCs: plasma cells; PFS: progression-free survival; qRT-PCR: quantitative reverse transcription PCR; RPS6KB1: ribosomal protein S6 kinase B1; SD: standard deviation; siRNA: small interfering RNA; SQSTM1: sequestosome 1; STV: starvation; TUBB: tubulin beta class I.

Impact of Natural Dietary Agents on Multiple Myeloma Prevention and Treatment: Molecular Insights and Potential for Clinical Translation

Chemoprevention is based on the use of non-toxic, pharmacologically active agents to prevent tumor progression. In this regard, natural dietary agents have been described by the most recent literature as promising tools for controlling onset and progression of malignancies. Extensive research has been so far performed to shed light on the effects of natural products on tumor growth and survival, disclosing the most relevant signal transduction pathways targeted by such compounds. Overall, anti-inflammatory, anti-oxidant and cytotoxic effects of dietary agents on tumor cells are supported either by results from epidemiological or animal studies and even by clinical trials. Multiple myeloma is a hematologic malignancy characterized by abnormal proliferation of bone marrow plasma cells and subsequent hypercalcemia, renal dysfunction, anemia, or bone disease, which remains incurable despite novel emerging therapeutic strategies. Notably, increasing evidence supports the capability of dietary natural compounds to antagonize multiple myeloma growth in preclinical models of the disease, underscoring their potential as candidate anti-cancer agents. In this review, we aim at summarizing findings on the anti-tumor activity of dietary natural products, focusing on their molecular mechanisms, which include inhibition of oncogenic signal transduction pathways and/or epigenetic modulating effects, along with their potential clinical applications against multiple myeloma and its related bone disease.

The Non-Coding RNA Landscape of Plasma Cell Dyscrasias

Despite substantial advancements have been done in the understanding of the pathogenesis of plasma cell (PC) disorders, these malignancies remain hard-to-treat. The discovery and subsequent characterization of non-coding transcripts, which include several members with diverse length and mode of action, has unraveled novel mechanisms of gene expression regulation often malfunctioning in cancer. Increasing evidence indicates that such non-coding molecules also feature in the pathobiology of PC dyscrasias, where they are endowed with strong therapeutic and/or prognostic potential. In this review, we aim to summarize the most relevant findings on the biological and clinical features of the non-coding RNA landscape of malignant PCs, with major focus on multiple myeloma. The most relevant classes of non-coding RNAs will be examined, along with the mechanisms accounting for their dysregulation and the recent strategies used for their targeting in PC dyscrasias. It is hoped these insights may lead to clinical applications of non-coding RNA molecules as biomarkers or therapeutic targets/agents in the near future.

MicroRNAs as major regulators of the autophagy pathway

Autophagy is a cellular stress response mechanism activation of which leads to degradation of cellular components, including proteins as well as damaged organelles in lysosomes. Defects in autophagy mechanisms were associated with several pathologies (e.g. cancer, neurodegenerative diseases, and rare genetic diseases). Therefore, autophagy regulation is under strict control. Transcriptional and post-translational mechanisms that control autophagy in cells and organisms studied in detail. Recent studies introduced non-coding small RNAs, and especially microRNAs (miRNAs) in the post-translational orchestration of the autophagic activity. In this review article, we analyzed in detail the current status of autophagy-miRNA connections. Comprehensive documentation of miRNAs that were directly involved in autophagy regulation resulted in the emergence of common themes and concepts governing these complex and intricate interactions. Hence, a better and systematic understanding of these interactions reveals a central role for miRNAs in the regulation of autophagy.

Epigenetic Control of Autophagy in Cancer Cells: A Key Process for Cancer-Related Phenotypes

Although autophagy is a well-known and extensively described cell pathway, numerous studies have been recently interested in studying the importance of its regulation at different molecular levels, including the translational and post-translational levels. Therefore, this review focuses on the links between autophagy and epigenetics in cancer and summarizes the. following: (i) how ATG genes are regulated by epigenetics, including DNA methylation and post-translational histone modifications; (ii) how epidrugs are able to modulate autophagy in cancer and to alter cancer-related phenotypes (proliferation, migration, invasion, tumorigenesis, etc.) and; (iii) how epigenetic enzymes can also regulate autophagy at the protein level. One noteable observation was that researchers most often reported conclusions about the regulation of the autophagy flux, following the use of epidrugs, based only on the analysis of LC3B-II form in treated cells. However, it is now widely accepted that an increase in LC3B-II form could be the consequence of an induction of the autophagy flux, as well as a block in the autophagosome-lysosome fusion. Therefore, in our review, all the published results describing a link between epidrugs and autophagy were systematically reanalyzed to determine whether autophagy flux was indeed increased, or inhibited, following the use of these potentially new interesting treatments targeting the autophagy process. Altogether, these recent data strongly support the idea that the determination of autophagy status could be crucial for future anticancer therapies. Indeed, the use of a combination of epidrugs and autophagy inhibitors could be beneficial for some cancer patients, whereas, in other cases, an increase of autophagy, which is frequently observed following the use of epidrugs, could lead to increased autophagy cell death.

miR-29b attenuates histone deacetylase-4 mediated podocyte dysfunction and renal fibrosis in diabetic nephropathy

Purpose

As epigenetic modifications like chromatin histone modifications have been suggested to play a role in the pathophysiology of Diabetic Nephropathy (DN) and are also found to be regulated by microRNAs. Our main purpose was to explore the role of microRNA in histone modulations associated with DN. There is downregulation of miR-29b due to advanced glycation end products in diabetes. Histone Deacetylase-4 (HDAC4) is amongst the histone modulators which promotes podocytes' impairment and upregulates transforming growth factor-1 (TGF-β1) leading to renal fibrosis. Moreover, macrophage infiltration causes podocytes' apoptosis and IL-6 mediated inflammation. As miR-29b is downregulated in diabetes and HDAC4, TGF-β1 and IL-6 could be the possible therapeutic targets in DN, our study was focussed on unveiling the role of miR-29b in modulation of HDAC4 and hence, in podocyte dysfunction and renal fibrosis in DN.

Methods

In silico analysis and luciferase assay were done to study the interaction between miR-29b and HDAC4. In-vitro DN model was developed in podocytes and miR-29b mimics were transfected. Also, podocytes were co-cultured with macrophage and miR-29b mimics were transfected. At the end, in-vivo DN model was generated in C57BL/6 J male mice and the effect of miR-29b mimics was reconfirmed.

Results

It was found that miR-29b targets the 3' untranslated region of HDAC4. In both in-vitro and in-vivo DN model, downregulation of miR-29b and subsequent increase in HDAC4 expression was observed. The miR-29b mimics suppressed podocytes' inflammation mediated through macrophages and attenuated HDAC4 expression, glomerular damage and renal fibrosis.

Conclusion

This study concludes that miR-29b regulates the expression of HDAC4 which plays a role in controlling renal fibrosis and podocytes' impairment in DN.

MicroRNAs and exosomes: Small molecules with big actions in multiple myeloma pathogenesis

Multiple myeloma (MM), an incurable hematologic malignancy of plasma cells increasing in the bone marrow (BM), has a complex microenvironment made to support proliferation, survival, and drug resistance of tumor cells. MicroRNAs (miRNAs), short non-coding RNAs regulating genes expression at posttranscriptional level, have been indicated to be functionally deregulated or abnormally expressed in MM cells. Moreover, by means of miRNAs, tumor microenvironment also modulates the function of MM cells. Consistently, it has been demonstrated that miRNA levels regulation impairs their interaction with the microenvironment of BM as well as create considerable antitumor feature even capable of overcoming the protective BM milieu. Communication between cancer stromal cells and cancer cells is a key factor in tumor progression. Finding out this interaction is important to develop effective approaches that reverse bone diseases. Exosomes, nano-vehicles having crucial roles in cell-to-cell communication, through targeting their cargos (i.e., miRNAs, mRNAs, DNAs, and proteins), are implicated in MM pathogenesis.

Novel miR-29b target regulation patterns are revealed in two different cell lines

MicroRNAs (miRNAs) are a class of small non-coding RNAs that regulate gene or protein expression by targeting mRNAs and triggering either translational repression or mRNA degradation. Distinct expression levels of miRNAs, including miR-29b, have been detected in various biological fluids and tissues from a large variety of disease models. However, how miRNAs "react" and function in different cellular environments is still largely unknown. In this study, the regulation patterns of miR-29b between human and mouse cell lines were compared for the first time. CRISPR/Cas9 gene editing was used to stably knockdown miR-29b in human cancer HeLa cells and mouse fibroblast NIH/3T3 cells with minimum off-targets. Genome editing revealed mir-29b-1, other than mir-29b-2, to be the main source of generating mature miR-29b. The editing of miR-29b decreased expression levels of its family members miR-29a/c via changing the tertiary structures of surrounding nucleotides. Comparing transcriptome profiles of human and mouse cell lines, miR-29b displayed common regulation pathways involving distinct downstream targets in macromolecular complex assembly, cell cycle regulation, and Wnt and PI3K-Akt signalling pathways; miR-29b also demonstrated specific functions reflecting cell characteristics, including fibrosis and neuronal regulations in NIH/3T3 cells and tumorigenesis and cellular senescence in HeLa cells.

HDAC4 Levels Control Sensibility toward Cisplatin in Gastric Cancer via the p53-p73/BIK Pathway

Gastric cancer (GC) remains a health issue due to the low efficiency of therapies, such as cisplatin. This unsatisfactory situation highlights the necessity of finding factors impacting GC sensibility to therapies. We analyzed the cisplatin pangenomic response in cancer cells and found HDAC4 as a major epigenetic regulator being inhibited. HDAC4 mRNA repression was partly mediated by the cisplatin-induced expression of miR-140. At a functional level, HDAC4 inhibition favored cisplatin cytotoxicity and reduced tumor growth. Inversely, overexpression of HDAC4 inhibits cisplatin cytotoxicity. Importantly, HDAC4 expression was found to be elevated in gastric tumors compared to healthy tissues, and in particular in specific molecular subgroups. Furthermore, mutations in HDAC4 correlate with good prognosis. Pathway analysis of genes whose expression in patients correlated strongly with HDAC4 highlighted DNA damage, p53 stabilization, and apoptosis as processes downregulated by HDAC4. This was further confirmed by silencing of HDAC4, which favored cisplatin-induced apoptosis characterized by cleavage of caspase 3 and induction of proapoptotic genes, such as BIK, in part via a p53-dependent mechanism. Altogether, these results reveal HDAC4 as a resistance factor for cisplatin in GC cells that impacts on patients' survival.

The Role and Function of microRNA in the Pathogenesis of Multiple Myeloma

Recently, attention has been drawn to the role of non-coding regions of the genome in cancer pathogenesis. MicroRNAs (miRNAs) are small non-coding RNAs with 19–25 bases of length that control gene expression by destroying messenger RNA or inhibiting its translation. In multiple myeloma (MM), the expression of several miRNAs, such as miR-15a and miR-16, is markedly decreased and their target genes upregulated, suggesting their role as tumor-suppressing miRNAs. In contrast, miRNAs such as miR-21 and miR-221 are highly expressed and function as oncogenes (oncomiRs). In addition, several miRNAs, such as those belonging to the miR-34 family, are transcriptional targets of p53 and mediate its tumor-suppressive functions. Many miRNAs are associated with drug resistance, and the modulation of their expression or activity might be explored to reverse it. Moreover, miRNA expression patterns in either MM cells or serum exosomes have been shown to be good prognostic markers. miRNA regulation mechanisms have not been fully elucidated. Many miRNAs are epigenetically controlled by DNA methylation and histone modification, and others regulate the expression of epigenetic modifiers, indicating that miRNA and other epigenetic effectors are part of a network. In this review, we outlined the roles of miRNAs in MM and their potential to predict MM prognosis and develop novel therapies.

Ectopic expression of BIRC5-targeting miR-101-3p overcomes bone marrow stroma-mediated drug resistance in multiple myeloma cells

Background

Multiple myeloma (MM) cells gain protection against drugs through interaction with bone marrow stromal cells (BMSCs). This form of resistance largely accounts for resistance to therapy in MM patients which warrants further exploration to identify more potential therapeutic targets.

Methods

We performed miRNA/mRNA qPCR arrays and western blotting to analyze transcriptional and translational changes in MM cells co-cultured with BMSCs. Drug cytotoxicity and apoptosis in MM^GFP-BMSC co-cultures were measured using fluorescence plate reader and flowcytometry, respectively. miRNA was overexpressed in MM cell lines using Lentiviral transduction, miRNA-3’UTR binding was examined using luciferase assay.

Results

We found that BMSCs downregulated miR-101-3p and upregulated survivin (BIRC5) in MM cells. Survivin was downregulated by miR-101-3p overexpression and found to be a direct target of miR-101-3p using 3’UTR luciferase assay. Overexpression of survivin increased viability of MM cells in the presence of anti-myeloma drugs, and miR-101-3p inhibition by anti-miR against miR-101-3p upregulated survivin. Furthermore, overexpression of miR-101-3p or silencing of survivin triggered apoptosis in MM cells and sensitized them to anti-myeloma drugs in the presence of BMSCs overcoming the stroma-induced drug resistance.

Conclusions

Our study demonstrates that BMSC-induced resistance to drugs is associated with survivin upregulation which is a direct target of miR-101-3p. This study also identifies miR-101-3p-survivin interaction as a druggable target involved in stroma-mediated drug resistance in MM and suggests it for developing more efficient therapeutic strategies.

Proteasome inhibitor induced SIRT1 deacetylates GLI2 to enhance hedgehog signaling activity and drug resistance in multiple myeloma

Multiple myeloma (MM) is still incurable despite the successful application of proteasome inhibitors in clinic. Bortezomib represents the most common chemotherapy for MM, whereas acquired drug resistance and eventually developed relapse remain the major obstruction. In the current study, we established bortezomib-resistant myeloma cell lines and screened gene expression profiles using single cell RNA-sequencing. Resistant MM cells exhibited increased clonogenic potential, specific metabolic, and epigenetic signatures, along with the self-renewal signaling characteristic of MM stem-like cells. Aberrant activation of hedgehog (Hh) signaling was correlated with drug resistance and stem cell-like transcriptional program. The key transcriptional factor GLI2 of the Hh pathway was restricted in the high acetylation and low ubiquitination states in bortezomib-resistant myeloma cells. Further investigation revealed that SIRT1 deacetylates and stabilizes GLI2 protein at lysine 757 and consequentially activates the Hh signaling, and itself serves as a direct target of Hh signaling to format a positive regulating loop. Using combination screening with an epigenetic compound library, we identified the SIRT1 specific inhibitor S1541 and S2804 had very obvious synergetic antimyeloma effect. Sirt1 inhibition could partially impeded the Hh pathway and conferred bortezomib sensitivity in vitro and in vivo. Notably, elevated SIRT1 level was also a prominent hallmark for the resistant myeloma cells, and this expression pattern was confirmed in myeloma patients, but independent of RAS/RAF mutations. Clinically, SIRT1 expression in patients with complete response was suppressed but elevated in relapsed patients, and retrospective analysis showed patients with higher SIRT1 expression had poorer outcomes. In conclusion, the cooperation of SIRT1 and Hh is an important mechanism of drug resistance in myeloma, and therapeutics combining SIRT1 inhibitors will sensitize myeloma cells to proteasome inhibitors.