MicroRNAs as regulators of death receptors signaling

Naringenin in combination with quercetin/fisetin shows synergistic anti-proliferative and migration reduction effects in breast cancer cell lines

INTRODUCTION & AIM

Breast cancer is one of the most common cancers with a high mortality rate among women worldwide. Quercetin/fisetin and naringenin, three well-known flavonoids, have been used to fight against various cancers. The aim of the present study was to investigate the possible synergism of quercetin/fisetin with naringenin on MCF7 and MDA-MB-231 breast cancer cell lines.

METHODS

In this study, cultured MCF7 and MDA-MB-231 cells were treated with different concentrations of quercetin/fisetin individually and in combination with naringenin. MTT assay and scratch assay was employed to determine cell viability and migration respectively. Real-time PCR was used to study the expression level of apoptosis genes and miR-1275 (tumor suppressor miRNA) and mir-27a-3p (oncogenic miRNA).

RESULTS

A synergism effect of quercetin/fisetin and naringenin (CI < 1) was observed for both cell lines. Combination therapies were significantly more effective in cell growth reduction, migration suppression and apoptosis induction than single therapies. Gene expression analysis revealed the upregulation of miR-1275 and downregulation miR-27a-3p.

CONCLUSION

Our results indicate that quercetin/fisetin enhances the anti-proliferative and anti-migratory activities in combination with naringenin in MCF7 and MDA-MB-231 human breast cancer cell lines. Therefore, the combination of Que/Fis and Nar can be proposed as a promising therapeutic strategy for further investigations.

MicroRNA-378 inhibits hepatocyte apoptosis during acute liver failure by targeting caspase-9 in mice

BACKGROUND

Acute liver failure (ALF) is a severe and potentially lethal clinical syndrome. It has been demonstrated that micro ribonucleic acids (miRNAs) are crucial mediators of nearly all pathological processes, including liver disease.

OBJECTIVE

The present study investigates the role of miR-378 in ALF. An ALF mouse model was induced using intraperitoneal injections of d-galactosamine/lipopolysaccharide (d-GalN/LPS). A hepatocyte cell line and miR-378 analogue were used in vitro to investigate the possible roles of miR-378 in ALF.

METHODS

The expressions of miR-378 and predicted target genes were measured via reverse transcription-quantitative polymerase chain reaction and western blotting, and cell apoptosis was assayed using flow cytometry.

RESULTS

Compared with mice in the control group, the mice challenged with d-GalN/LPS showed higher levels of alanine aminotransferase, aspartate aminotransferase, tumour necrosis factor-alpha and interleukin-6, more severe liver damage and increased numbers of apoptotic hepatocytes. Hepatic miR-378 was distinctly downregulated, while messenger RNA and protein levels of cysteinyl aspartate specific proteinase 9 (caspase-9) were upregulated in the ALF model. Furthermore, miR-378 was downregulated in d-GalN/TNF-induced hepatocyte cells, and miR-378 was found to inhibit hepatocyte apoptosis by targeting caspase-9.

CONCLUSION

Together, the present results indicate that miR-378 is a previously unrecognised post-ALF hepatocyte apoptosis regulator and may be a potential therapeutic target in the context of ALF.

50 years on and still very much alive: 'Apoptosis: a basic biological phenomenon with wide-ranging implications in tissue kinetics'

Cell death is part of the lifecycle of every multicellular organism. Nineteenth-century pathologists already recognised that organised forms of cell death must exist to explain the demise and turnover of cells during metamorphosis (of insects), embryogenesis and normal tissue homoeostasis [1]. Nevertheless, Kerr, Wyllie and Currie in their seminal paper of 1972, were the first to collate and define the distinct morphological features of controlled cell death in different contexts [2]. To describe the processes of cell deletion observed under both physiological and pathological conditions, they coined the term 'Apoptosis' (derived from the Greek word 'ἀπόπτωσις', meaning 'dropping off or falling off' of petals from flowers). Kerr, Wyllie and Currie defined apoptosis as a mechanism 'complementary to mitosis in the regulation of animal cell populations'. In addition, they already recognised the potential to use this programmed form of cell death for cancer therapy, but they also emphasised the occurrence of apoptosis during cancer development. In this article, some 50 years after its initial publication in The British Journal of Cancer, we revaluate and put the authors initial assumptions and general concepts about apoptosis into the context of modern-day biology.

miRNA Involvement in Cerebral Ischemia-Reperfusion Injury

Cerebral ischemia reperfusion injury is a debilitating medical condition, currently with only a limited amount of therapies aimed at protecting the cerebral parenchyma. Micro RNAs (miRNAs) are small, non-coding RNA molecules that via the RNA-induced silencing complex either degrade or prevent target messenger RNAs from being translated and thus, can modulate the synthesis of target proteins. In the neurological field, miRNAs have been evaluated as potential regulators in brain development processes and pathological events. Following ischemic hypoxic stress, the cellular and molecular events initiated dysregulate different miRNAs, responsible for long-terming progression and extension of neuronal damage. Because of their ability to regulate the synthesis of target proteins, miRNAs emerge as a possible therapeutic strategy in limiting the neuronal damage following a cerebral ischemic event. This review aims to summarize the recent literature evidence of the miRNAs involved in signaling and modulating cerebral ischemia-reperfusion injuries, thus pointing their potential in limiting neuronal damage and repair mechanisms. An in-depth overview of the molecular pathways involved in ischemia reperfusion injury and the involvement of specific miRNAs, could provide future perspectives in the development of neuroprotective agents targeting these specific miRNAs.

Proteus mirabilis Vesicles Induce Mitochondrial Apoptosis by Regulating miR96-5p/Abca1 to Inhibit Osteoclastogenesis and Bone Loss

Bone loss due to an increased osteoclast activity is common in osteoporosis and rheumatoid arthritis. For the first time, we observed an inhibition of osteoclast formation and bone resorption by outer-membrane vesicles (OMVs) from a Gram-negative, pathogenic bacterium, Proteus mirabilis (P.M). Gene ontogeny and KEGG enrichment analyses of miRNA and mRNA sequencing data demonstrated a significant effect of P.M OMVs on mitochondrial functions and apoptotic pathways. OMVs induced mitochondrial dysfunction through an increased level of intracellular ROS, collapse of mitochondrial membrane potential (ΔΨm), and modulation of Bax, Bcl-2, caspase-3, and cytochrome c expression. In addition, P.M OMVs strongly inhibited miR-96-5p expression, which caused an upregulation of ATP binding cassette subfamily A member 1 (Abca1) in osteoclasts leading to an increased level of mitochondria-dependent apoptosis. Moreover, treatment with P.M but not Escherichia coli OMVs attenuated bone loss in experimental osteoporosis and collagen-induced arthritis. Collectively, we demonstrated osteoprotective functions of OMVs from Proteus mirabilis, which downregulated miR-96-5p causing an increased Abca1 expression and mitochondria-dependent apoptosis.

The Role of Micro RNAs in Regulating PI3K/AKT Signaling Pathways in Glioblastoma

Glioblastoma is a type of brain cancer with aggressive and invasive nature. Such features result from increased proliferation and migration and also poor apoptosis of glioma cells leading to resistance to current treatments such as chemotherapy and radiotherapy. In recent studies, micro RNAs have been introduced as a novel target for treating glioblastoma via regulation of apoptotic signaling pathway, remarkably PI3K/AKT, which affect cellular functions and blockage or progression of the tumor. In this review, we focus on PI3K/AKT signaling pathway and other related apoptotic processes contributing to glioblastoma and investigate the role of micro RNAs interfering in apoptosis, invasion and proliferation of glioma through such apoptotic processes pathways. Databases NCBI, PubMed, and Web of Science were searched for published English articles using keywords such as 'miRNA OR microRNA', 'Glioblastoma', 'apoptotic pathways', 'PI3K and AKT', 'Caspase signaling Pathway' and 'Notch pathway'. Most articles were published from 7 May 2015 to 16 June 2020. This study focused on PI3K/AKT signaling pathway affecting glioma cells in separated subparts. Also, other related apoptotic pathways as the Caspase cycle and Notch have been also investigated. Nearly 40 miRNAs were found as tumor suppressors or onco-miRNA, and their targets, which regulated subcomponents participating in proliferation, invasion, and apoptosis of the tumoral cells. Our review reveals that miRNAs affect key molecules in signaling apoptotic pathways, partly PI3K/AKT, making them potential therapeutic targets to overcome the tumor. However, their utility as a novel treatment for glioblastoma requires further examination and investigation.

MicroRNA Expression Profiles in Autism Spectrum Disorder: Role for miR-181 in Immunomodulation

BACKGROUND

MicroRNAs (miRNAs) are important regulators of molecular pathways in psychiatric disease. Here, we examine differential miRNAs expression in lymphoblastoid cell lines (LCLs) derived from 10 individuals with autism spectrum disorder (ASD) and compare them to seven typically developing unrelated age- and gender-matched controls and 10 typically developing siblings. Small RNAseq analysis identified miRNAs, and selected miRNAs were validated using quantitative real-time polymerase reaction (qRT-PCR). KEGG analysis identified target pathways, and selected predicted mRNAs were validated using qRT-PCR.

RESULTS

Small RNAseq analysis identified that multiple miRNAs differentiated ASD from unrelated controls and ASD from typically developing siblings, with only one, hsa-miR-451a_R-1, being in common. Verification with qRT-PCR showed that miR-320a differentiated ASD from both sibling and unrelated controls and that several members of the miR-181 family differentiated ASD from unrelated controls. Differential expression of AKT2, AKT3, TNF α and CamKinase II predicted by KEGG analysis was verified by qRT-PCR. Expression of CamKinase II βwas found to be correlated with the severity of stereotyped behavior of the ASD participants.

CONCLUSIONS

This study provides insight into the mechanisms regulating molecular pathways in individuals with ASD and identifies differentiated regulated genes involved in both the central nervous system and the immune system.

β-Glucan: A dual regulator of apoptosis and cell proliferation

β-Glucans are polysaccharides generally obtained from the cell wall of bacteria, fungi, yeasts, and aleurone layer of cereals. β-Glucans are polymers, with β-1,3 glucose as core linear structure, but they differ in their main branch length, linkages and branching patterns, giving rise to high and low-molecular-weight β-glucans. They are well-known cell response modifiers with immune-modulating, nutraceutical and health beneficial effects, including anticancer and pro-apoptotic properties. β-Glucan extracts have shown positive responses in controlling tumor cell proliferation and activation of the immune system. The immunomodulatory action of β-glucans enhances the host's antitumor defense against cancer. In consonance with the above, many studies have shown that β-glucan treatment leads to the induction of apoptotic death of cancer cells. The ability of β-glucans to stimulate apoptotic pathways or the proteins involved in apoptosis prompting a new domain in cancer therapy. β-glucan can be a potential therapeutic agent for the treatment of cancer. However, there is a need to legitimize the β-glucan type, as most of the studies include β-glucan from different sources having different physicochemical properties. The body of literature presented here focuses on the effects of β-glucan on immunomodulation, proliferation, cell death and the possible mechanisms and pathways involved in these processes.

Resveratrol Activates Natural Killer Cells through Akt- and mTORC2-Mediated c-Myb Upregulation

Natural killer (NK) cells are suitable targets for cancer immunotherapy owing to their potent cytotoxic activity. To maximize the therapeutic efficacy of cancer immunotherapy, adjuvants need to be identified. Resveratrol is a well-studied polyphenol with various potential health benefits, including antitumor effects. We previously found that resveratrol is an NK cell booster, suggesting that it can serve as an adjuvant for cancer immunotherapy. However, the molecular mechanism underlying the activation of NK cells by resveratrol remains unclear. The present study aimed to determine this mechanism. To this end, we investigated relevant pathways in NK cells using Western blot, real-time polymerase chain reaction, pathway inhibitor, protein/DNA array, and cytotoxicity analyses. We confirmed the synergistic effects of resveratrol and interleukin (IL)-2 on enhancing the cytolytic activity of NK cells. Resveratrol activated Akt by regulating Mammalian Target of Rapamycin (mTOR) Complex 2 (mTORC2) via phosphatase and tensin homolog (PTEN) and ribosomal protein S6 kinase beta-1 (S6K1). Moreover, resveratrol-mediated NK cell activation was more dependent on the mTOR pathway than the Akt pathway. Importantly, resveratrol increased the expression of c-Myb, a downstream transcription factor of Akt and mTORC2. Moreover, c-Myb was essential for resveratrol-induced NK cell activation in combination with IL-2. Our results demonstrate that resveratrol activates NK cells through Akt- and mTORC2-mediated c-Myb upregulation.

Vincristine and prednisone regulates cellular and exosomal miR-181a expression differently within the first time diagnosed and the relapsed leukemia B cells

We explored the effect of vincristine and prednisone on cellular and exosomal miR-181a expression in first time diagnosed leukemia and relapsed leukemia. Vincristine and prednisone induced apoptosis/pro-apoptotic genes in first time diagnosed leukemia, and suppressed the cellular and exosomal miR-181a expression. In contrast, vincristine and prednisone could not induce apoptosis/pro-apoptotic genes in relapsed leukemia, and could not change the expression of cellular or exosomal miR-181a. In conclusion, the non-suppressive nature of miR-181a in relapsed leukemia might contribute to the chemo-resistance and this suggests a potential role of miR-181a-inhibitor along with the chemotherapy in the treatment of relapsed leukemia.

Silencing of Exosomal miR-181a Reverses Pediatric Acute Lymphocytic Leukemia Cell Proliferation

Exosomes are cell-generated nano-vesicles found in most biological fluids. Major components of their cargo are lipids, proteins, RNA, DNA, and non-coding RNAs. The miRNAs carried within exosomes reveal real-time information regarding disease status in leukemia and other cancers, and therefore exosomes have been studied as novel biomarkers for cancer. We investigated the impact of exosomes on cell proliferation in pediatric acute lymphocytic leukemia (PALL) and its reversal by silencing of exo-miR-181a. We isolated exosomes from the serum of PALL patients (Exo-PALL) and conditioned medium of leukemic cell lines (Exo-CM). We found that Exo-PALL promotes cell proliferation in leukemic B cell lines by gene regulation. This exosome-induced cell proliferation is a precise event with the up-regulation of proliferative (PCNA, Ki-67) and pro-survival genes (MCL-1, and BCL2) and suppression of pro-apoptotic genes (BAD, BAX). Exo-PALL and Exo-CM both show over expression of miR-181a compared to healthy donor control exosomes (Exo-HD). Specific silencing of exosomal miR-181a using a miR-181a inhibitor confirms that miR-181a inhibitor treatment reverses Exo-PALL/Exo-CM-induced leukemic cell proliferation in vitro. Altogether, this study suggests that exosomal miR-181a inhibition can be a novel target for growth suppression in pediatric lymphatic leukemia.

Role of the microRNA‑214/Bax axis in the progression of acute liver failure

Acute liver failure (ALF) is a fatal liver disease characterized by severe hepatocyte destruction. MicroRNAs (miRNAs/miRs) have been reported to serve a key role in a number of liver diseases. Therefore, the aim of the present study was to investigate the role and underlying mechanism of miR-214 in ALF. ALF murine and hepatocyte models were established using D-galactosamine (D-GalN) and lipopolysaccharide (LPS) or D-GalN + tumor necrosis factor (TNF)-α, respectively. The expression levels of miR-214 and Bax were detected by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and/or western blotting. Furthermore, an automatic biochemical analyzer was used to measure the levels of aspartate aminotransferase (AST) or alanine aminotransferase (ALT). The levels of TNF-α and interleukin (IL)-6 were detected by ELISA and RT-qPCR. In addition, TUNEL staining and flow cytometry were used to analyze cell apoptosis, and the protein expression of caspase-3 was determined by western blotting. It was identified that the levels of AST and ALT were increased and that hepatocyte apoptosis was enhanced in the D-GalN/LPS-stimulated group compared with the control. Furthermore, higher expression of caspase-3 was observed in the D-GalN/LPS-stimulated group. In addition, it was demonstrated that miR-214 was downregulated, while Bax was upregulated in D-GalN/LPS-stimulated mice and D-GalN/TNF-α-stimulated BNLCL2 cells. Moreover, in D-GalN/TNF-α-stimulated BNLCL2 cells, miR-214 overexpression suppressed apoptosis and decreased TNF-α and IL-6 levels, and these effects were reversed by the Bax plasmid. It was also identified that overexpression of miR-214 significantly decreased Bax mRNA and protein expression levels in vitro. Collectively, the present results suggested that miR-214 inhibited hepatocyte apoptosis during ALF development via targeting Bax, thus indicating that miR-214 may be a potential target for ALF treatment.

Circulating miRNAs as Potential Biomarkers in Myasthenia Gravis: Tools for Personalized Medicine

Myasthenia gravis (MG) is an autoimmune disease caused by antibodies which attack receptors at the neuromuscular junction. One of the main difficulties in predicting the clinical course of MG is the heterogeneity of the disease, where disease progression differs greatly depending on the subgroup that the patient is classified into. MG subgroups are classified according to: age of onset [early-onset MG (EOMG; onset ≤ 50 years) versus late-onset MG (LOMG; onset > 50 years]; the presence of a thymoma (thymoma-associated MG); antibody subtype [acetylcholine receptor antibody seropositive (AChR+) and muscle-specific tyrosine kinase antibody seropositive (MuSK+)]; as well as clinical subtypes (ocular versus generalized MG). The diagnostic tests for MG, such as antibody titers, neurophysiological tests, and objective clinical fatigue score, do not necessarily reflect disease progression. Hence, there is a great need for reliable objective biomarkers in MG to follow the disease course as well as the individualized response to therapy toward personalized medicine. In this regard, circulating microRNAs (miRNAs) have emerged as promising potential biomarkers due to their accessibility in body fluids and unique profiles in different diseases, including autoimmune disorders. Several studies on circulating miRNAs in MG subtypes have revealed specific miRNA profiles in patients’ sera. In generalized AChR+ EOMG, miR-150-5p and miR-21-5p are the most elevated miRNAs, with lower levels observed upon treatment with immunosuppression and thymectomy. In AChR+ generalized LOMG, the miR-150-5p, miR-21-5p, and miR-30e-5p levels are elevated and decrease in accordance with the clinical response after immunosuppression. In ocular MG, higher levels of miR-30e-5p discriminate patients who will later generalize from those remaining ocular. In contrast, in MuSK+ MG, the levels of the let-7 miRNA family members are elevated. Studies of circulating miRNA profiles in Lrp4 or agrin antibody-seropositive MG are still lacking. This review summarizes the present knowledge of circulating miRNAs in different subgroups of MG.

The Emerging Roles of miR-125b in Cancers

MicroRNAs (miRNAs) are endogenous, noncoding, single-stranded RNA molecules of 22 nucleotides in length. MiRNAs have both tumor-suppressive properties and oncogenic properties that can control critical processes in tumors. Mature miR-125b originates from miR-125b-1 and miR-125b-2 and leads to the degradation of target mRNAs or the inhibition of translation through binding to the 3′ untranslated regions (3′-UTR) of target mRNAs. Importantly, miR-125b is involved in regulating NF-κB, p53, PI3K/Akt/mTOR, ErbB2, Wnt, and another signaling pathways, thereby controlling cell proliferation, differentiation, metabolism, apoptosis, drug resistance and tumor immunity. This review aims to summarize the recent literature on the role of miR-125b in the regulation of tumorigenesis and to explore its potential clinical application in the diagnosis, prognosis and clinical treatment of tumors.

A Novel lncRNA HOXC-AS3 Acts as a miR-3922-5p Sponge to Promote Breast Cancer Metastasis

Purpose: The function of long noncoding RNAs (lncRNA) in breast cancer metastasis remains largely unknown. In this work, the role of HOXC-AS3 in breast cancer progression was investigated.Methods: By using Cancer Genome Atlas (TCGA) Database, we investigated the expression of HOXC-AS3 in breast cancer and explored the association between HOXC-AS3 expression and prognosis. Then, we studied the biological function of HOXC-AS3 in cell migration and invasion both in vitro and in vivo. Furthermore, the target miRNA of HOXC-AS3, and the target mRNA of miR-3922-5p were proved.Results: HOXC-AS3 is aberrantly overexpressed in breast cancers especially the HER2⁺ type. Moreover, high expression of HOXC-AS3 has a relationship with poor clinical outcomes of breast cancer. In addition, HOXC-AS3 regulates cell Invasion and migration both in vitro and in vivo. Our results demonstrated that miR-3922-5p was a direct target of HOXC-AS3, and PPP1R1A was a target of miR-3922-5p in breast cancer.Conclusions: The novel lncRNA HOXC-AS3 acts as a miR-3922-5p sponge to upregulate PPP1R1A protein expression, and thus results in promoting breast cancer metastasis. HOXC-AS3 could be a novel therapeutic target for breast cancer therapeutics.

miR-19a Is Involved In Progression And Malignancy Of Anaplastic Thyroid Cancer Cells

Background

MicroRNAs (miRNAs) are endogenous, single-stranded, non-coding RNAs acting as negative regulators of gene expression involved in a number of physiological processes. MiRNAs' expression is commonly dysregulated in many types of human tumor diseases and cancers, including thyroid cancers, and is often involved in tumor initiation and progression. miR-19a, a member of miR-17-92 cluster, has been demonstrated to promote cell growth in anaplastic thyroid cancer (ATC), the most advanced and aggressive thyroid cancer.

Purpose

In this work, we investigate the potential contribution of miR-19a in thyroid cancer cells poor prognosis and de-differentiation.

Methods

We directly modulated the expression of miR-19a in papillary (PTC) and anaplastic thyroid carcinoma cell lines through transfection of specific miR-19a mimic or inhibitor. Further, we performed gene expression analysis of specific genes to evaluate miR-19a association with cell cycle, differentiation, and poor prognosis.

Results

Our data indicate that miR-19a overexpression in PTC cells significantly promotes cell growth, decreases the expression of differentiation genes and activates poor prognosis genes. Its inhibition in ATC cells reduces cell proliferation and the expression of genes related to poor prognosis but does not affect differentiation.

Conclusion

Our findings reveal the existence of functional associations between miR-19a expression and thyroid cancer progression and malignancy suggesting miR-19a as a novel candidate therapeutic target for ATC.

MiR-122-5p and miR-326-3p: Potential novel biomarkers for early detection of cadmium exposure

Cadmium is a common environmental and occupational pollutant and can produce toxic effects in a range of organs, especially in kidneys, after long-term exposure. MicroRNAs are ideal candidate biomarkers for various types of disorders, including renal diseases. In this study, we profiled the global miRNA expressions in rat kidneys using miRNA microarrays and found a collection of differentially expressed miRNAs induced by cadmium exposure. Among all of the candidate miRNAs, we identified miR-122-5p and miR-326-3p as early biomarkers for cadmium-induced nephrotoxicity. The two-miRNA signature was validated by quantitative real-time PCR in HK-2 and NRK-52E cells, rat kidney, serum and urine samples, and serum of an occupational population. Our results indicate that miR-122-5p and miR-326-3p may be potential biomarkers for cadmium exposure.

MicroRNAs in cancer cell death pathways: Apoptosis and necroptosis

To protect tissues and the organism from disease, potentially harmful cells are removed through programmed cell death processes, including apoptosis and necroptosis. These types of cell death are critically controlled by microRNAs (miRNAs). MiRNAs are short RNA molecules that target and inhibit expression of many cellular regulators, including those controlling programmed cell death via the intrinsic (Bcl-2 and Mcl-1), extrinsic (TRAIL and Fas), p53-and endoplasmic reticulum (ER) stress-induced apoptotic pathways, as well as the necroptosis cell death pathway. In this review, we discuss the current knowledge of apoptosis and necroptosis pathways and how these are impaired in cancer cells. We focus on how miRNAs disrupt apoptosis and necroptosis, thereby critically contributing to malignancy. Understanding which and how miRNAs and their targets affect cell death pathways could open up novel therapeutic opportunities for cancer patients. Indeed, restoration of pro-apoptotic tumor suppressor miRNAs (apoptomiRs) or inhibition of oncogenic miRNAs (oncomiRs) represent strategies that are currently being trialed or are already applied as miRNA-based cancer therapies. Therefore, better understanding the cancer type-specific expression of apoptomiRs and oncomiRs and their underlying mechanisms in cell death pathways will not only advance our knowledge, but also continue to provide new opportunities to treat cancer.

Differential microRNA Profile in Operational Tolerance: A Potential Role in Favoring Cell Survival

Background: Operational tolerance (OT) is a state of graft functional stability that occurs after at least 1 year of immunosuppressant withdrawal. MicroRNAs (microRNA) are small non-coding RNAs that downregulate messenger RNA/protein expression of innumerous molecules and are critical for homeostasis. We investigated whether OT in kidney transplantation displays a differential microRNA profile, which would suggest that microRNAs participate in Operational Tolerance mechanisms, and may reveal potential molecular pathways.

Methods: We first compared serum microRNA in OT (n = 8) with chronic rejection (CR) (n = 5) and healthy individuals (HI) (n = 5), using a 768-microRNA qPCR-panel. We used the Thermo Fisher Cloud computing platform to compare the levels of microRNAs in the OT group in relation to the other study groups. We performed validation experiments for miR-885-5p, by q-PCR, in a larger number of study subjects (OT = 8, CR = 12, HI = 12), as individual samples.

Results: We detected a differential microRNA profile in OT vs. its opposing clinical outcome—CR—suggesting that microRNAs may integrate transplantation tolerance mechanisms. Some miRNAs were detected at higher levels in OT: miR-885-5p, miR-331-3p, miR-27a-5p vs. CR; others, we found at lower levels: miR-1233-3p, miR-572, miR-638, miR-1260a. Considering highly predicted/experimentally demonstrated targets of these miRNAs, bioinformatics analysis revealed that the granzyme B, and death receptor pathways are dominant, suggesting that cell death regulation integrates transplantation tolerance mechanisms. We confirmed higher miR-885-5p levels in OT vs. CR, and vs. HI, in a larger number of subjects.

Conclusions: We propose that epigenetics mechanisms involving microRNAs may integrate human transplantation tolerance mechanisms, and regulate key members of the cell death/survival signaling. miR-885-5p could favor cell survival in OT by diminishing the levels of CRADD/RAIDD and CASP3. Nonetheless, given the nature of any complex phenomenon in humans, only cumulative data will help to determine whether this microRNA differential profile may be related to the cause or consequence of operational tolerance.

Serum levels of miR-29, miR-122, miR-155 and miR-192 are elevated in patients with cholangiocarcinoma

Objectives

Cholangiocarcinoma (CCA) represents the second most common primary hepatic malignancy. Despite tremendous research activities, the prognosis for the majority of patients is still poor. Only in case of early diagnosis, liver resection might potentially lead to long-term survival. However, it is still unclear which patients benefit most from extensive liver surgery, highlighting the need for new diagnostic and prognostic stratification strategies.

Methods

Serum concentrations of a 4 miRNA panel (miR-122, miR-192, miR-29b and miR-155) were analyzed using semi-quantitative reverse-transcriptase PCR in serum samples from 94 patients with cholangiocarcinoma undergoing tumour resection and 40 healthy controls. Results were correlated with clinical data.

Results

Serum concentrations of miR-122, miR-192, miR-29b and miR-155 were significantly elevated in patients with CCA compared to healthy controls or patients with primary sclerosing cholangitis without malignant transformation. Although preoperative levels of these miRNAs were unsuitable as a prognostic marker of survival, a strong postoperative decline of miR-122 serum levels was significantly associated with a favorable patients’ prognosis.

Conclusions

Analysis of circulating miRNAs represents a promising tool for the diagnosis of even early stage CCA. A postoperative decline in miRNA serum concentrations might be indicative for a favorable patients’ outcome and helpful to identify patients with a good prognosis after extended liver surgery.

MiR-19a Overexpression in FTC-133 Cell Line Induces a More De-Differentiated and Aggressive Phenotype

In recent years, microRNAs (miRNAs) have received increasing attention for their important role in tumor initiation and progression. MiRNAs are a class of endogenous small non-coding RNAs that negatively regulate the expression of several oncogenes or tumor suppressor genes. MiR-19a, a component of the oncogenic miR-17-92 cluster, has been reported to be highly expressed only in anaplastic thyroid cancer, the most undifferentiated, aggressive and lethal form of thyroid neoplasia. In this work, we evaluated the putative contribution of miR-19a in de-differentiation and aggressiveness of thyroid tumors. To this aim, we induced miR-19a expression in the well-differentiated follicular thyroid cancer cell line and evaluated proliferation, apoptosis and gene expression profile of cancer cells. Our results showed that miR-19a overexpression stimulates cell proliferation and alters the expression profile of genes related to thyroid cell differentiation and aggressiveness. These findings not only suggest that miR-19a has a possible involvement in de-differentiation and malignancy, but also that it could represent an important prognostic indicator and a good therapeutic target for the most aggressive thyroid cancer.

MicroRNA-146 protects A549 and H1975 cells from LPS-induced apoptosis and inflammation injury

Pneumonia is an inflammatory condition affecting the lungs, in which pro-inflammatory cytokines are secreted. It has been shown that microRNA-146 (miR-146) is involved in the regulation of immune and inflammatory responses. The present study explored the protective effects of miR-146 overexpression on lipopolysaccharide (LPS)-mediated injury in A549 and H1975 cells. In this study, A549 and H1975 cells were transfected with miR-146 mimic or inhibitor, and then were subjected with LPS. Thereafter, cell viability, colony formation capacity, apoptosis, the release of proinflammatory factors, Sirt1 expression, and the expression of NF-κB and Notch pathway proteins were respectively assessed. As a result, miR- 146 overexpression exerted protective functions on LPS-damaged A549 and H1975 cells, as evidenced by the increases in cell viability and colony number, the decrease in apoptotic cell rate, as well as the down-regulations of IL-1, IL-6, and TNF-α. Sirt1 can be positively regulated by miR-146. Furthermore, miR-146 overexpression blocked NF-κB and Notch pathways, while these blocking effects were abolished when Sirt1 was silenced. The findings in the current study indicated that miR-146 protected A549 and H1975 cells from LPS-induced apoptosis and inflammation injury. miR-146 exerted protective functions might be via up-regulation of Sirt1 and thereby blocking NF-κB and Notch pathways.

miR‑21‑5p regulates type II alveolar epithelial cell apoptosis in hyperoxic acute lung injury

Hyperoxia-induced acute lung injury (HALI) as one of the most common complications in patents on mechanical ventilation, and there are no efficient methods to overcome this at present. It was hypothesized that microRNA 21-5p(miR-21-5p) can promote the survival of type II alveolar epithelial cells (AECII), alleviating HALI. The present study aimed to combine gene chip analysis with the overexpression miR-21-5p to develop a novel therapeutic option for HALI. It was found that AECII apoptosis was an important pathogenic event in the development of HALI, and the overexpression of miR-21-5p prevented HALI, associated with reducing AECII apoptosis. These results were obtained using adenoviral/lentiviral vectors, which overexpressed miR-21-5p, to transfect AECII cells in vitro and in vivo. It was found that the overexpression of miR-21-5p reduced the apoptotic rate of the AECII cells. In addition, miR-21-5p decreased the ratio of B-cell lymphoma 2 (Bcl-2)-associated X protein/Bcl-2 and the expression of caspase-3. It was also revealed that the overexpression of miR-21-5p alleviated acute lung injury in adult rats exposed to a hyperoxic environment. These results suggest that miR-21-5p may become a novel therapeutic option for patients with HALI, by protecting AECII cells from apoptosis.

Circulating microRNAs as potential biomarkers in myasthenia gravis patients

MicroRNAs (miRNAs) are small noncoding RNA molecules that bind to specific mRNA targets and regulate a wide range of important biological processes within cells. Circulating miRNAs are released into the extracellular space and can be measured in most biofluids, including blood serum and plasma. Recently, circulating miRNAs have emerged as easily accessible markers in various body fluids with different profiles and quantities specific for different human disorders, including autoimmune diseases. In myasthenia gravis (MG), diagnostic tests such as titers of serum autoantibodies specific for either the acetylcholine receptor (AChR⁺ ) or muscle-specific tyrosine kinase (MuSK⁺ ) do not necessarily reflect disease progression, and there is a great need for reliable objective biomarkers to monitor the disease course and therapeutic response. Recent studies in AChR⁺ MG revealed elevated levels of the immuno-miRNAs miR-150-5p and miR-21-5p. Of particular importance, levels of miR-150-5p were lower in immunosuppressed patients and in patients with clinical improvement following thymectomy. In MuSK⁺ MG, another profile of circulating miRNAs was found, including upregulation of the let-7 family of miRNAs. Here, we summarize the potential role of circulating miRNAs as biomarkers in general and in MG, and highlight important considerations for the analysis of circulating miRNA.

MiR-24 induces chemotherapy resistance and hypoxic advantage in breast cancer

Breast cancer remains one of the leading causes of cancer mortality among women. It has been proved that the onset of cancer depends on a very small pool of tumor cells with a phenotype similar to that of normal adult stem cells. Cancer stem cells (CSC) possess self-renewal and multilineage differentiation potential as well as a robust ability to sustain tumorigenesis. Evidence suggests that CSCs contribute to chemotherapy resistance and to survival under hypoxic conditions. Interestingly, hypoxia in turn regulates self-renewal in CSCs and these effects may be primarily mediated by hypoxic inducible factors (HIFs). Recently, microRNAs (miRNAs) have emerged as critical players in the maintenance of pluripotency and self-renewal in normal and cancer stem cells. Here, we demonstrate that miR-24 is upregulated in breast CSCs and that its overexpression increases the number of mammospheres and the expression of stem cell markers. MiR-24 also induces apoptosis resistance through the regulation of BimL expression. Moreover, we identify a new miR-24 target, FIH1, which promotes HIFα degradation: miR-24 increases under hypoxic conditions, causing downregulation of FIH1 and upregulation of HIF1α. In conclusion, miR-24 hampers chemotherapy-induced apoptosis in breast CSCs and increases cell resistance to hypoxic conditions through an FIH1−HIFα pathway.

MicroRNA-519a-3p mediates apoptosis resistance in breast cancer cells and their escape from recognition by natural killer cells

Aggressive breast cancer is associated with poor patient outcome and characterized by the development of tumor cell variants that are able to escape from control of the immune system or are resistant to targeted therapies. The complex molecular mechanisms leading to immune escape and therapy resistance are incompletely understood. We have previously shown that high miR-519a-3p levels are associated with poor survival in breast cancer. Here, we demonstrate that miR-519a-3p confers resistance to apoptosis induced by TRAIL, FasL and granzyme B/perforin by interfering with apoptosis signaling in breast cancer cells. MiR-519a-3p diminished the expression of its direct target genes for TRAIL-R2 (TNFRSF10B) and for caspase-8 (CASP8) and its indirect target gene for caspase-7 (CASP7), resulting in reduced sensitivity and tumor cell apoptosis in response to apoptotic stimuli. Furthermore, miR-519a-3p impaired tumor cell killing by natural killer (NK) cells via downregulation of the NKG2D ligands ULBP2 and MICA on the surface of tumor cells that are crucial for the recognition of these tumor cells by NK cells. We determined that miR-519a-3p was overexpressed in more aggressive mutant TP53 breast cancer that was associated with poor survival. Furthermore, low levels of TRAIL-R2, caspase-7 and caspase-8 correlated with poor survival, suggesting that the inhibitory effect of miR-519a-3p on TRAIL-R2 and caspases may have direct clinical relevance in lowering patient’s prognosis. In conclusion, we demonstrate that miR-519a-3p is a critical factor in mediating resistance toward cancer cell apoptosis and impairing tumor cell recognition by NK cells. This joint regulation of apoptosis and immune cell recognition through miR-519a-3p supports the hypothesis that miRNAs are key regulators of cancer cell fate, facilitating cancer progression and evasion from immunosurveillance at multiple and interconnected levels.

Combination of AAV-TRAIL with miR-221-Zip Therapeutic Strategy Overcomes the Resistance to TRAIL Induced Apoptosis in Liver Cancer

TNF-related apoptosis-inducing ligand (TRAIL) possesses the capacity to induce apoptosis in a wide variety of tumor cells without affecting most normal cells. However, it has now emerged that many primary cancer cells are resistant to TRAIL monotherapy. Overcoming the intrinsic or acquired TRAIL resistance is desirable for TRAIL-mediated cancer therapy. In this study, we found that the miR-221/222 cluster was up-regulated in TRAIL-resistant liver cancer cells. Specific inhibitors of miR-221 and/or miR-222, called sponge, TuD and miR-Zip were constructed, and their ability to overcome TRAIL resistance was compared. Among them, AAV-mediated gene therapy using co-expression of TRAIL with miR-221-Zip showed the most synergistic activity in the induction of apoptosis in vitro. In vivo treatment of nude mice bearing human TRAIL-resistant liver cancer xenografts with AAV-TRAIL-miR-221-Zip also led to growth inhibition. This sensitizing effect of miR-221-Zip was associated with increased expression of PTEN, the miR-221 target, as well as with decreasing levels of Survivin. Moreover, miR-221 expression was concomitant with promotion of Survivin expression and suppression of PTEN expression. TRAIL sensitivity of cancer cells isolated from liver cancer tissues or from patients was significantly correlated with miR-221 expression. And miR-221 blood expression levels in liver cancer patients were correlated with TRAIL sensitivity, thus it had the potential to be a predictor of TRAIL sensitivity in liver cancer. These data suggested the potential of combining AAV-TRAIL with miR-221-Zip as a therapeutic intervention for liver cancer.

TRAIL, Wnt, Sonic Hedgehog, TGFβ, and miRNA Signalings Are Potential Targets for Oral Cancer Therapy

Clinical studies and cancer cell models emphasize the importance of targeting therapies for oral cancer. The tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is highly expressed in cancer, and is a selective killing ligand for oral cancer. Signaling proteins in the wingless-type mouse mammary tumor virus (MMTV) integration site family (Wnt), Sonic hedgehog (SHH), and transforming growth factor β (TGFβ) pathways may regulate cell proliferation, migration, and apoptosis. Accordingly, the genes encoding these signaling proteins are potential targets for oral cancer therapy. In this review, we focus on recent advances in targeting therapies for oral cancer and discuss the gene targets within TRAIL, Wnt, SHH, and TGFβ signaling for oral cancer therapies. Oncogenic microRNAs (miRNAs) and tumor suppressor miRNAs targeting the genes encoding these signaling proteins are summarized, and the interactions between Wnt, SHH, TGFβ, and miRNAs are interpreted. With suitable combination treatments, synergistic effects are expected to improve targeting therapies for oral cancer.

TTBK2 circular RNA promotes glioma malignancy by regulating miR-217/HNF1β/Derlin-1 pathway

BACKGROUND

Circular RNAs are a subgroup of non-coding RNAs and generated by a mammalian genome. Herein, the expression and function of circular RNA circ-TTBK2 were investigated in human glioma cells.

METHODS

Fluorescence in situ hybridization and quantitative real-time PCR were conducted to profile the cell distribution and expression of circ-TTBK2 and microRNA-217 (miR-217) in glioma tissues and cells. Immunohistochemical and western blot were used to determine the expression of HNF1β and Derlin-1 in glioma tissues and cells. Stable knockdown of circ-TTBK2 or overexpression of miR-217 glioma cell lines (U87 and U251) were established to explore the function of circ-TTBK2 and miR-217 in glioma cells. Further, luciferase reports and RNA immunoprecipitation were used to investigate the correlation between circ-TTBK2 and miR-217. Cell Counting Kit-8, transwell assays, and flow cytometry were used to investigate circ-TTBK2 and miR-217 function including cell proliferation, migration and invasion, and apoptosis, respectively. ChIP assays were used to ascertain the correlations between HNF1β and Derlin-1.

RESULTS

We found that circ-TTBK2 was upregulated in glioma tissues and cell lines, while linear TTBK2 was not dysregulated in glioma tissues and cells. Enhanced expression of circ-TTBK2 promoted cell proliferation, migration, and invasion, while inhibited apoptosis. MiR-217 was downregulated in glioma tissues and cell lines. We also found that circ-TTBK2, but not linear TTBK2, acted as miR-217 sponge in a sequence-specific manner. In addition, upregulated circ-TTBK2 decreased miR-217 expression and there was a reciprocal negative feedback between them in an Argonaute2-dependent manner. Moreover, reintroduction of miR-217 significantly reversed circ-TTBK2-mediated promotion of glioma progression. HNF1β was a direct target of miR-217, and played oncogenic role in glioma cells. Remarkably, circ-TTBK2 knockdown combined with miR-217 overexpression led to tumor regression in vivo.

CONCLUSIONS

These results demonstrated a novel role circ-TTBK2 in the glioma progression.

Altered expression of apoptosis-regulating miRNAs in salivary gland tumors suggests their involvement in salivary gland tumorigenesis

Salivary gland tumors comprise a heterogeneous group of lesions with different histological features and diverse clinical pathophysiology. They account for about 3% of all head and neck tumors. Apoptosis plays an important role during morphogenesis of glandular structures, including that of the salivary gland. Recent studies have demonstrated that several microRNAs (miRNAs) are involved in the control of apoptosis. The aim of the present study was to determine the expression of apoptosis-related miRNAs (miR-15a, miR-16, miR-17-5p, miR-20a, miR-21, miR-29, and miR-34) and their target mRNAs in 25 pleomorphic adenomas, 23 mucoepidermoid carcinomas, and 10 non-neoplastic salivary gland samples by real-time RT-PCR. We observed upregulation of miR-15a, miR-16, miR-17-5p, miR-21, miR-29, and miR-34a in pleomorphic adenomas. The expression of miR-21 and miR-34a was upregulated in 91 and 74% of mucoepidermoid carcinomas, respectively. Downregulation of miR-20a was observed in 75% of pleomorphic adenomas and in 57% of mucoepidermoid carcinomas. APAF1, BAX, BCL2, BID, CASP2, CASP8, DIABLO , and TP53 transcripts were upregulated in both tumor types. BAD transcripts were upregulated in pleomorphic adenomas. CASP3 and CASP6 transcripts were upregulated in mucoepidermoid carcinomas. BCL2, CASP2, CASP6, and CASP8 proteins were mostly absent in mucoepidermoid carcinomas but expressed in few cells in pleomorphic adenomas. Our study provides evidence of alterations in the expression of apoptosis-regulating miRNAs in salivary gland tumors, suggesting possible involvement of these microRNAs in salivary gland tumorigenesis.

Migration-prone glioma cells show curcumin resistance associated with enhanced expression of miR-21 and invasion/anti-apoptosis-related proteins

In study, the expression patterns and functional differences between an original glioma cell population (U251 and U87) and sublines (U251-P10, U87-P10) that were selected to be migration-prone were investigated. The expressions levels of VEGF and intracellular adhesion molecule-1 (ICAM-1) were increased in the migration-prone sublines as well as in samples from patients with high-grade glioma when compared to those with low-grade glioma. In addition, cells of the migration-prone sublines showed increased expression of the oncogenic microRNA. miR-21, which was also associated with more advanced clinical pathological stages in the patient tissue specimens. Treatment of U251 cells with an miR-21 mimic dramatically enhanced the migratory activity and expression of anti-apoptotic proteins. Furthermore, treatment with curcumin decreased the miR-21 level and anti-apoptotic protein expression, and increased the expression of pro-apoptosis proteins and microtubule-associated protein light chain 3-II (LC3-II) in U251 cells. The migration-prone sublines showed decreased induction of cell death markers in response to curcumin treatment. Finally, U251-P10 cells showed resistance against curcumin treatment. These results suggest that miR-21 is associated with regulation of the migratory ability and survival in human glioma cells. These findings suggest novel mechanisms of malignancy and new potential combinatorial strategies for the management of malignant glioma.

Targeting the metabolic pathway of human colon cancer overcomes resistance to TRAIL-induced apoptosis

Colon cancer is a leading cause of cancer-related mortality for which targeted therapy is needed; however, trials using apoptosis-inducing ligand monotherapy to overcome resistance to apoptosis have not shown clinical responses. Since colon cancer cells selectively uptake and rapidly metabolize glucose, a property utilized for clinical staging, we investigated mechanisms to alter glucose metabolism in order to selectively target the cancer cells and to overcome evasion of apoptosis. We demonstrate TRAIL (tumor necrosis factor-related apoptosis-inducing ligand) resistance in the majority of human colon cancers tested and utilize the glucose analog 2-deoxy-d-glucose to sensitize TRAIL-resistant gastrointestinal adenocarcinoma cells, and not normal gastrointestinal epithelial cells, to TRAIL-induced apoptosis through enhanced death receptor 5 expression, downstream modulation of MAPK signaling and subsequent miRNA expression modulation by increasing the expression of miR-494 via MEK activation. Further, established human colon cancer xenografts treated with this strategy experience anti-tumor responses. These findings in colon adenocarcinoma support further investigation of manipulation of cellular energetics to selectively overcome resistance to apoptosis and to impart tumor regressions in established colon cancer tumors.

Characterization of three human cell line models for high-throughput neuronal cytotoxicity screening

More than 75 000 man-made chemicals contaminate the environment; many of these have not been tested for toxicities. These chemicals demand quantitative high-throughput screening assays to assess them for causative roles in neurotoxicities, including Parkinson's disease and other neurodegenerative disorders. To facilitate high throughput screening for cytotoxicity to neurons, three human neuronal cellular models were compared: SH-SY5Y neuroblastoma cells, LUHMES conditionally-immortalized dopaminergic neurons, and Neural Stem Cells (NSC) derived from human fetal brain. These three cell lines were evaluated for rapidity and degree of differentiation, and sensitivity to 32 known or candidate neurotoxicants. First, expression of neural differentiation genes was assayed during a 7-day differentiation period. Of the three cell lines, LUHMES showed the highest gene expression of neuronal markers after differentiation. Both in the undifferentiated state and after 7 days of neuronal differentiation, LUHMES cells exhibited greater cytotoxic sensitivity to most of 32 suspected or known neurotoxicants than SH-SY5Y or NSCs. LUHMES cells were also unique in being more susceptible to several compounds in the differentiating state than in the undifferentiated state; including known neurotoxicants colchicine, methyl-mercury (II), and vincristine. Gene expression results suggest that differentiating LUHMES cells may be susceptible to apoptosis because they express low levels of anti-apoptotic genes BCL2 and BIRC5/survivin, whereas SH-SY5Y cells may be resistant to apoptosis because they express high levels of BCL2, BIRC5/survivin, and BIRC3 genes. Thus, LUHMES cells exhibited favorable characteristics for neuro-cytotoxicity screening: rapid differentiation into neurons that exhibit high level expression neuronal marker genes, and marked sensitivity of LUHMES cells to known neurotoxicants. Copyright © 2016 John Wiley & Sons, Ltd.

Aptamer-MiRNA Conjugates for Cancer Cell-Targeted Delivery

microRNAs (miRNAs) are short noncoding RNAs that effectively regulate the expression of a wide variety of genes. Increasing evidences have shown a fundamental role of miRNAs in cancer initiation and progression, thus indicating these molecules among the most promising for new approaches in cancer therapy. However, several hurdles limit the translation of miRNAs into the clinic. One of the most critical aspects is represented by the lack of a safe and reliable way to selectively target organs and tissues. Therefore, the development of cell-specific delivery means has become an essential step for the translation of miRNA-based therapeutics to clinic for cancer management. To this end aptamer-based approaches may provide efficient delivery tools for the selective accumulation of miRNA to target tumors, their intracellular uptake, processing, and functional silencing of target genes. In this chapter, we discuss the direct conjugation of miRNAs to aptamers against transmembrane receptors as innovative experimental approach for their selective delivery to cancer cells.

microRNA regulators of apoptosis in cancer

This brief review summarizes our current knowledge on the microRNAs that regulate apoptosis machinery and are potentially involved in the dysregulation or deregulation of apoptosis, a well known hallmark of cancer. microRNAs are critical regulators of the most important cellular processes, including apoptosis. Expression of microRNAs is found to be dysregulated in many malignancies, leading to apoptosis inhibition in cancer, or resistance to current therapies. To date, there are over 80 microRNAs directly involved in apoptosis regulation or dysregulation that can impact cancer detection, initiation, progression, invasion, metastasis or resistance to anti-cancer therapy. Development of microRNA-based therapeutic strategies is now taking shape in the clinic. Thus, these microRNAs represent potential targets or tools for cancer therapy in the future.

Aptamer-miRNA-212 Conjugate Sensitizes NSCLC Cells to TRAIL

TNF-related apoptosis-inducing ligand (TRAIL) is a promising antitumor agent for its remarkable ability to selectively induce apoptosis in cancer cells, without affecting the viability of healthy bystander cells. The TRAIL tumor suppressor pathway is deregulated in many human malignancies including lung cancer. In human non-small cell lung cancer (NSCLC) cells, sensitization to TRAIL therapy can be restored by increasing the expression levels of the tumor suppressor microRNA-212 (miR-212) leading to inhibition of the anti-apoptotic protein PED/PEA-15 implicated in treatment resistance. In this study, we exploited a previously described RNA aptamer inhibitor of the tyrosine kinase receptor Axl (GL21.T) expressed on lung cancer cells, as a means to deliver miR-212 into human NSCLC cells expressing Axl. We demonstrate efficient delivery of miR-212 following conjugation of the miR to GL21.T (GL21.T-miR212 chimera). We show that the chimera downregulates PED and restores TRAIL-mediate cytotoxicity in cancer cells. Importantly, treatment of Axl+ lung cancer cells with the chimera resulted in (i) an increase in caspase activation and (ii) a reduction of cell viability in combination with TRAIL therapy. In conclusion, we demonstrate that the GL21.T-miR212 chimera can be employed as an adjuvant to TRAIL therapy for the treatment of lung cancer.

Impact of broiler egg storage on the relative expression of selected blastoderm genes associated with apoptosis, oxidative stress, and fatty acid metabolism

Cool temperature storage of eggs prior to incubation is a frequent practice by commercial broiler hatcheries. However, continued storage beyond 7 d leads to a progressive increase in the rate of early embryonic mortality. In this study, we examined the relative expression of 31 genes associated with fatty acid metabolism (8), apoptosis (7), and oxidative stress (16) pathways to better understand the basis of embryo mortality during egg storage. A total of 642 broiler eggs in 2 separate trials were subjected to the following egg treatments: stored 4 d (Control 1, C1); stored 21 d but subjected to short periods of incubation during egg storage (SPIDES); stored un-manipulated 21 d (NonSPIDES, NS); and stored 4 d then incubated for 10 h to advance the embryos to the same developmental stages as the SPIDES embryos (Control 2, C2). Hatchability trials (277 eggs) confirmed the efficacy of SPIDES compared to NS treatments in both trials. To determine relative expression of 31 selected genes, 365 blastoderms were isolated, staged, and flash frozen in batches of 5 to 10 blastoderms per vial (7 vials per egg treatment) prior to RNA extractions. Analysis of gene expression was performed using qRT-PCR and the results presented as relative expression normalized to C1. The relative expression of genes in which the SPIDES and C2 treatments were significantly up- or down-regulated in tandem indicated that the stage-specific expression of those genes was maintained by the SPIDES treatment. This study provides the relative gene expressions of blastodermal cells before and after prolonged egg storage as well as insight as to how SPIDES impacts blastodermal cell gene expression.

MicroRNA-222 regulates muscle alternative splicing through Rbm24 during differentiation of skeletal muscle cells

A number of microRNAs have been shown to regulate skeletal muscle development and differentiation. MicroRNA-222 is downregulated during myogenic differentiation and its overexpression leads to alteration of muscle differentiation process and specialized structures. By using RNA-induced silencing complex (RISC) pulldown followed by RNA sequencing, combined with in silico microRNA target prediction, we have identified two new targets of microRNA-222 involved in the regulation of myogenic differentiation, Ahnak and Rbm24. Specifically, the RNA-binding protein Rbm24 is a major regulator of muscle-specific alternative splicing and its downregulation by microRNA-222 results in defective exon inclusion impairing the production of muscle-specific isoforms of Coro6, Fxr1 and NACA transcripts. Reconstitution of normal levels of Rbm24 in cells overexpressing microRNA-222 rescues muscle-specific splicing. In conclusion, we have identified a new function of microRNA-222 leading to alteration of myogenic differentiation at the level of alternative splicing, and we provide evidence that this effect is mediated by Rbm24 protein.

Study of microRNAs-21/221 as potential breast cancer biomarkers in Egyptian women

microRNAs (miRNAs) play an important role in cancer prognosis. They are small molecules, approximately 17-25 nucleotides in length, and their high stability in human serum supports their use as novel diagnostic biomarkers of cancer and other pathological conditions. In this study, we analyzed the expression patterns of miR-21 and miR-221 in the serum from a total of 100 Egyptian female subjects with breast cancer, fibroadenoma, and healthy control subjects. Using microarray-based expression profiling followed by real-time polymerase chain reaction validation, we compared the levels of the two circulating miRNAs in the serum of patients with breast cancer (n=50), fibroadenoma (n=25), and healthy controls (n=25). The miRNA SNORD68 was chosen as the housekeeping endogenous control. We found that the serum levels of miR-21 and miR-221 were significantly overexpressed in breast cancer patients compared to normal controls and fibroadenoma patients. Receiver Operating Characteristic (ROC) curve analysis revealed that miR-21 has greater potential in discriminating between breast cancer patients and the control group, while miR-221 has greater potential in discriminating between breast cancer and fibroadenoma patients. Classification models using k-Nearest Neighbor (kNN), Naïve Bayes (NB), and Random Forests (RF) were developed using expression levels of both miR-21 and miR-221. Best classification performance was achieved by NB Classification models, reaching 91% of correct classification. Furthermore, relative miR-221 expression was associated with histological tumor grades. Therefore, it may be concluded that both miR-21 and miR-221 can be used to differentiate between breast cancer patients and healthy controls, but that the diagnostic accuracy of serum miR-21 is superior to miR-221 for breast cancer prediction. miR-221 has more diagnostic power in discriminating between breast cancer and fibroadenoma patients. The overexpression of miR-221 has been associated with the breast cancer grade. We also demonstrated that the combined expression of miR-21 and miR-221can be successfully applied as breast cancer biomarkers.

Molecular mechanisms of apoptosis and roles in cancer development and treatment

Programmed cell death (PCD) or apoptosis is a mechanism which is crucial for all multicellular organisms to control cell proliferation and maintain tissue homeostasis as well as eliminate harmful or unnecessary cells from an organism. Defects in the physiological mechanisms of apoptosis may contribute to different human diseases like cancer. Identification of the mechanisms of apoptosis and its effector proteins as well as the genes responsible for apoptosis has provided a new opportunity to discover and develop novel agents that can increase the sensitivity of cancer cells to undergo apoptosis or reset their apoptotic threshold. These novel targeted therapies include those targeting anti-apoptotic Bcl-2 family members, p53, the extrinsic pathway, FLICE-inhibitory protein (c-FLIP), inhibitor of apoptosis (IAP) proteins, and the caspases. In recent years a number of these novel agents have been assessed in preclinical and clinical trials. In this review, we introduce some of the key regulatory molecules that control the apoptotic pathways, extrinsic and intrinsic death receptors, discuss how defects in apoptotic pathways contribute to cancer, and list several agents being developed to target apoptosis.

Smart functional nucleic acid chimeras: enabling tissue specific RNA targeting therapy

A major obstacle for effective utilization of therapeutic oligonucleotides such as siRNA, antisense, antimiRs etc. is to deliver them specifically to the target tissues. Toward this goal, nucleic acid aptamers are re-emerging as a prominent class of biomolecules capable of delivering target specific therapy and therapeutic monitoring by various molecular imaging modalities. This class of short oligonucleotide ligands with high affinity and specificity are selected from a large nucleic acid pool against a molecular target of choice. Poor cellular uptake of therapeutic oligonucleotides impedes gene-targeting efficacy in vitro and in vivo. In contrast, aptamer-oligonucleotide chimeras have shown the capacity to deliver siRNA, antimiRs, small molecule drugs etc. toward various targets and showed very promising results in various studies on different diseases models. However, to further improve the bio-stability of such chimeric conjugates, it is important to introduce chemically-modified nucleic acid analogs. In this review, we highlight the applications of nucleic acid aptamers for target specific delivery of therapeutic oligonucleotides.

The microRNA regulatory network: a far-reaching approach to the regulate the Wnt signaling pathway in number of diseases

Wnt signaling pathway plays an important role in cell renewal, tumorigenesis, organogenesis, bone formation and bone resorption. Wnt signaling pathway is divided into two outlets: Wnt-β-catenin pathway (canonical pathway) and Wnt-calcium pathway (non-canonical pathway). miRNAs play a key role in the regulation of Wnt signaling pathway. In this review, we highlight the basic indulgent of miRNAs-mediated regulation of Wnt signaling pathway. We focus on the role of miRNAs at different levels of Wnt signaling: signaling molecules, their associated signaling proteins, regulatory proteins, transcription factors and related cytokines. Finally, we concluded that these multiple levels of targeting may have diagnostic potential as well as therapeutic prospective in future treatment.

MicroRNAs Regulate Mitochondrial Function in Cerebral Ischemia-Reperfusion Injury

Cerebral ischemia-reperfusion injury involves multiple independently fatal terminal pathways in the mitochondria. These pathways include the reactive oxygen species (ROS) generation caused by changes in mitochondrial membrane potential and calcium overload, resulting in apoptosis via cytochrome c (Cyt c) release. In addition, numerous microRNAs are associated with the overall process. In this review, we first briefly summarize the mitochondrial changes in cerebral ischemia-reperfusion and then describe the possible molecular mechanism of miRNA-regulated mitochondrial function, which likely includes oxidative stress and energy metabolism, as well as apoptosis. On the basis of the preceding analysis, we conclude that studies of microRNAs that regulate mitochondrial function will expedite the development of treatments for cerebral ischemia-reperfusion injury.

The regulatory roles of non-coding RNAs in nerve injury and regeneration

Non-coding RNAs (ncRNAs), especially microRNAs (miRNAs) and long non-coding RNAs (lncRNAs), have attracted much attention since their regulatory roles in diverse cell processes were recognized. Emerging studies demonstrate that many ncRNAs are differentially expressed after injury to the nervous system, significantly affecting nerve regeneration. In this review, we compile the miRNAs and lncRNAs that have been reported to be dysregulated following a variety of central and peripheral nerve injuries, including acquired brain injury, spinal cord injury, and peripheral nerve injury. We also list investigations on how these miRNAs and lncRNAs exert the regulatory actions in neurodegenerative and neuroregenerative processes through different mechanisms involving their interaction with target coding genes. We believe that comprehension of the expression profiles and the possible functions of ncRNAs during the processes of nerve injury and regeneration will help understand the molecular mechanisms responsible for post-nerve-injury changes, and may contribute to the potential use of ncRNAs as a diagnostic marker and therapeutic target for nerve injury.

Effects of microRNA-221/222 on cell proliferation and apoptosis in prostate cancer cells

OBJECTIVE

To investigate the role of miR-221/222 in cell proliferation and apoptosis in human prostate cancer cells, and examine the effects of miR-221/222 on caspase-10 expression.

METHODS

Prostate cancer cells were transfected with miR-221/222 mimics or inhibitors. Cell proliferation was assessed by MTT assay. The expression levels of miR-221/222 were detected with quantitative real-time PCR. Apoptosis was induced with TNF-α/CHX treatment, and evaluated by Hoechst 33342 staining, propidium iodide (PI) flow cytometric analysis, caspase-3 activity measurement, and Western blot analysis. Luciferase activity assay, quantitative real-time PCR, and Western blot were performed to evaluate the effects of miR-221/222 on caspase-10 expression.

RESULTS

Our results showed that miR-221/222 could promote the proliferation of prostate cancer cells, including LNCaP and PC3 cells. After transfection and apoptosis induction, Hoechst 33342 staining and PI flow cytometric assay showed that apoptosis was dramatically decreased in prostate cancer cells treated with miR-221/222 mimics. Moreover, caspase-3 activity was dramatically decreased, and the cleaved forms of caspase-3 were reduced, in the miR-221/222 mimic-treated group. On the contrary, miR-221/222 knockdown sensitized the prostate cancer cells to TNF-α/CHX-induced apoptosis. In addition, a negative correlation was observed between the expressions of miR-221/222 and caspase-10 in prostate cancer cells. miR-221/222 could repress the expression of caspase-10, which was confirmed by the luciferase reporter assay.

CONCLUSION

miR-221/222 promote cell proliferation and repress apoptosis, through suppressing caspase-10, in prostate cancer cells. Our results provide promising evidence for the miRNA-based therapeutic strategy of prostate cancers.

Inhibition of methyltransferases accelerates degradation of cFLIP and sensitizes B-cell lymphoma cells to TRAIL-induced apoptosis

Non-Hodgkin lymphomas (NHLs) are characterized by specific abnormalities that alter cell cycle regulation, DNA damage response, and apoptotic signaling. It is believed that cancer cells are particularly sensitive to cell death induced by tumor necrosis factor α–related apoptosis-inducing ligand (TRAIL). However, many cancer cells show blocked TRAIL signaling due to up-regulated expression of anti-apoptotic factors, such as cFLIP. This hurdle to TRAIL’s tumor cytotoxicity might be overcome by combining TRAIL-based therapy with drugs that reverse blockages of its apoptotic signaling. In this study, we investigated the impact of a pan-methyltransferase inhibitor (3-deazaneplanocin A, or DZNep) on TRAIL-induced apoptosis in aggressive B-cell NHLs: mantle cell, Burkitt, and diffuse large B-cell lymphomas. We characterized TRAIL apoptosis regulation and caspase activation in several NHL-derived cell lines pre-treated with DZNep. We found that DZNep increased cancer cell sensitivity to TRAIL signaling by promoting caspase-8 processing through accelerated cFLIP degradation. No change in cFLIP mRNA level indicated independence of promoter methylation alterations in methyltransferase activity induced by DZNep profoundly affected cFLIP mRNA stability and protein stability. This appears to be in part through increased levels of cFLIP-targeting microRNAs (miR-512-3p and miR-346). However, additional microRNAs and cFLIP-regulating mechanisms appear to be involved in DZNep-mediated enhanced response to extrinsic apoptotic stimuli. The capacity of DZNep to target cFLIP expression on multiple levels underscores DZNep’s potential in TRAIL-based therapies for B-cell NHLs.