The involvement of miR-23a/APAF1 regulation axis in colorectal cancer

DNA-functionalized MOF fluorescent probes for the enzyme-free and pretreatment-free detection of MicroRNA in serum

MicroRNA (miRNA) is a promising biomarker that plays an important role in various biomedical applications, especially in cancer diagnosis. However, the current miRNA detection technology has inherent limitations such as complex operation, expensive testing cost and excessive detection time. In this study, a dual signal amplification biosensor based on DNA-functionalized metal-organic frameworks (MOFs) fluorescent probes, MFPBiosensor, was established for the enzyme-free and pretreatment-free detection of the colon cancer (CC) marker miR-23a. DNA-functionalized MOFs NH2-MIL-53(Al) (DNA@MOFs) were synthesized as fluorescent probes with specific recognition functions. A single DNA@MOF carries a large number of fluorescent ligands 2-aminoterephthalic acid (NH2-H2BDC), which can generate strong fluorescence signals after alkaline hydrolysis. Combined with catalyzed hairpin assembly (CHA), an efficient isothermal amplification technique, the dual signal enhancement strategy reduced matrix interference and sensitized the signal response. The established MFPBiosensor successfully detected extremely low levels of miRNA in complex biological samples with acceptable sensitivity and specificity. With a single detection cost of $0.583 and a test time of 50 min, the excellent inexpensive and rapid advantage of the MFPBiosensor is highlighted. More importantly, the subtle design enables the MFPBiosensor to achieve convenient batch detection, where miRNA in serum can be directly detected without any pretreatment process or enzyme. In conclusion, MFPBiosensor is a promising biosensor with substantial potential for commercial miRNA detection and clinical diagnostic applications of CC.

Comparison of Oncogenes, Tumor Suppressors, and MicroRNAs Between Schizophrenia and Glioma: The Balance of Power

The risk of cancer in schizophrenia has been controversial. Confounders of the issue are cigarette smoking in schizophrenia, and antiproliferative effects of antipsychotic medications. The author has previously suggested comparison of a specific cancer like glioma to schizophrenia might help determine a more accurate relationship between cancer and schizophrenia. To accomplish this goal, the author performed three comparisons of data; the first a comparison of conventional tumor suppressors and oncogenes between schizophrenia and cancer including glioma. This comparison determined schizophrenia has both tumor-suppressive and tumor-promoting characteristics. A second, larger comparison between brain-expressed microRNAs in schizophrenia with their expression in glioma was then performed. This identified a core carcinogenic group of miRNAs in schizophrenia offset by a larger group of tumor-suppressive miRNAs. This proposed "balance of power" between oncogenes and tumor suppressors could cause neuroinflammation. This was assessed by a third comparison between schizophrenia, glioma and inflammation in asbestos-related lung cancer and mesothelioma (ALRCM). This revealed that schizophrenia shares more oncogenic similarity to ALRCM than glioma.

Comprehensive Profiling of Hypoxia-Related miRNAs Identifies miR-23a-3p Overexpression as a Marker of Platinum Resistance and Poor Prognosis in High-Grade Serous Ovarian Cancer

Simple Summary

In the present paper, we identified miR-23a-3p, a hypoxia regulated-microRNA (miRNA), as a potential biomarker of chemoresistance and poor outcome in two independent cohorts of high-grade serous ovarian carcinoma (HGSOC) patients. Then, we predicted the involvement of miR-23a-3p in the platinum resistance pathway, together with its target APAF-1 gene, and validated their anticorrelation and association with platinum response in HGSOC patients and cell lines. We propose that the evaluation of miR-23a-3p expression may provide important clinical indications on patients not responding to platinum treatment and that the miR23a-3p/APAF1 axis could be considered a possible target for personalized medicine in HGSOC patients.

Abstract

The onset of chemo-resistant recurrence represents the principal cause of high-grade serous ovarian carcinoma (HGSOC) death. HGSOC masses are characterized by a hypoxic microenvironment, which contributes to the development of this chemo-resistant phenotype. Hypoxia regulated-miRNAs (HRMs) represent a molecular response of cancer cells to hypoxia and are involved in tumor progression. We investigated the expression of HRMs using miRNA expression data from a total of 273 advanced-stage HGSOC samples. The miRNAs associated with chemoresistance and survival were validated by RT-qPCR and target prediction, and comparative pathway analysis was conducted for target gene identification. Analysis of miRNA expression profiles indicated miR-23a-3p and miR-181c-5p over-expression as associated with chemoresistance and poor PFS. RT-qPCR data confirmed upregulation of miR-23a-3p in tumors from chemoresistant HGSOC patients and its significant association with shorter PFS. In silico miR-23a-3p target prediction and comparative pathway analysis identified platinum drug resistance as the pathway with the highest number of miR-23a-3p target genes. Among them, APAF-1 emerged as the most promising, being downregulated in platinum-resistant patients and in HGSOC chemo-resistant cells. These results highlight miR-23a-3p as a potential biomarker for HGSOC platinum response and prognosis and the miR23a-3p/APAF1 axis as a possible target to overcome platinum-resistance.

Dissecting miRNA signature in colorectal cancer progression and metastasis

Colorectal cancer (CRC) is the third most common cancer and leading cause of cancer related deaths worldwide. Despite recent advancements in surgical and molecular targeted therapies that improved the therapeutic efficacy in CRC, the 5 years survival rate of CRC patients still remains frustratingly poor. Accumulated evidences indicate that microRNAs (miRNAs) play a crucial role in the progression and metastasis of CRC. Dysregulated miRNAs are closely associated with cancerous phenotypes (e.g. enhanced proliferative and invasive ability, evasion of apoptosis, cell cycle aberration, and promotion of angiogenesis) by regulating their target genes. In this review, we provide an updated overview of tumor suppressive and oncogenic miRNAs, circulatory miRNAs, and the possible causes of dysregulated miRNAs in CRC. In addition, we discuss the important functions of miRNAs in drug resistance of CRC.

Differential Expression of miR-21, miR-23a, and miR-27a, and Their Diagnostic Significance in Egyptian Colorectal Cancer Patients

Background: Colorectal cancer (CRC) rates are affected by genetics, ethnicity, and environmental factors; it is considered one of the most aggressive human malignancies with high mortality and morbidity rates worldwide due, in part, to its asymptomatic nature during the early stages of disease. Objective: Owing to the impact of microRNA (miRNA) dysregulation on CRC development and progression, this study was conducted to explore the expression levels of mir-21, -23a, and -27a in the sera and tissues of Egyptian CRC patients and to evaluate their diagnostic efficacy based on circulating levels. Methods: In the test phase, the relative expression levels of the studied miRNAs were evaluated in the sera of 70 participants (35 CRC patients and 35 healthy controls) using quantitative real-time-polymerase chain reaction and to verify their diagnostic value. The exploratory phase was designed to validate the tumor-derived trait by comparing the miRNA levels in the cancerous and adjacent noncancerous tissues. Results: The relative expression levels of the studied miRNAs were significantly upregulated in both serum and tumor tissues of the patients compared to their corresponding controls. In addition, significant positive correlations were found between the relative expression levels of the studied miRNAs in serum samples and their levels in the matched CRC tissues. The serum expression levels of mir-21 and -23a were more predictive of CRC than mir-27a. Conclusion: Circulating mir-21, -23a, and -27a expression levels appear to be valuable diagnostic biomarkers for CRC, especially when combined.

RNA-seq analysis identifies cytoskeletal structural genes and pathways for meat quality in beef

RNA sequencing (RNA-seq) has allowed for transcriptional profiling of biological systems through the identification of differentially expressed (DE) genes and pathways. A total of 80 steers with extreme phenotypes were selected from the University of Florida multibreed Angus-Brahman herd. The average slaughter age was 12.91±8.69 months. Tenderness, juiciness and connective tissue assessed by sensory panel, along with marbling, Warner-Bratzler Shear Force (WBSF) and cooking loss, were measured in longissimus dorsi muscle. Total RNA was extracted from muscle and one RNA-seq library per sample was constructed, multiplexed, and sequenced based on protocols by Illumina HiSeq-3000 platform to generate 2×101 bp paired-end reads. The overall read mapping rate using the Btau_4.6.1 reference genome was 63%. A total of 8,799 genes were analyzed using two different methodologies, an expression association and a DE analysis. A gene and exon expression association analysis was carried out using a meat quality index on all 80 samples as a continuous response variable. The expression of 208 genes and 3,280 exons from 1,565 genes was associated with the meat quality index (p-value ≤ 0.05). A gene and isoform DE evaluation was performed analyzing two groups with extreme WBSF, tenderness and marbling. A total of 676 (adjusted p-value≤0.05), 70 (adjusted p-value≤0.1) and 198 (adjusted p-value≤0.1) genes were DE for WBSF, tenderness and marbling, respectively. A total of 106 isoforms from 98 genes for WBSF, 13 isoforms from 13 genes for tenderness and 43 isoforms from 42 genes for marbling (FDR≤0.1) were DE. Cytoskeletal and transmembrane anchoring genes and pathways were identified in the expression association, DE and the gene enrichment analyses; these proteins can have a direct effect on meat quality. Cytoskeletal proteins and transmembrane anchoring molecules can influence meat quality by allowing cytoskeletal interaction with myocyte and organelle membranes, contributing to cytoskeletal structure and architecture maintenance postmortem.

bta-miR-23a Regulates the Myogenic Differentiation of Fetal Bovine Skeletal Muscle-Derived Progenitor Cells by Targeting MDFIC Gene

miR-23a, a member of the miR-23a/24-2/27a cluster, has been demonstrated to play pivotal roles in many cellular activities. However, the mechanisms of how bta-miR-23a controls the myogenic differentiation (MD) of PDGFRα⁻ bovine progenitor cells (bPCs) remain poorly understood. In the present work, bta-miR-23a expression was increased during the MD of ^PDGFRα− bPCs. Moreover, bta-miR-23a overexpression significantly promoted the MD of ^PDGFRα− bPCs. Luciferase reporter assays showed that the 3’-UTR region of MDFIC (MyoD family inhibitor domain containing) could be a promising target of bta-miR-23a, which resulted in its post-transcriptional down-regulation. Additionally, the knockdown of MDFIC by siRNA facilitated the MD of ^PDGFRα− bPCs, while the overexpression of MDFIC inhibited the activating effect of bta-miR-23a during MD. Of note, MDFIC might function through the interaction between MyoG transcription factor and MEF2C promoter. This study reveals that bta-miR-23a can promote the MD of ^PDGFRα− bPCs through post-transcriptional downregulation of MDFIC.

MicroRNA-23a promotes colorectal cancer cell migration and proliferation by targeting at MARK1

The functional role of microRNA-23a in tumorigenesis has been investigated; however, the exact mechanism of microRNA-23a (miR-23a) in colorectal cancer development has not been fully explored. In the present study, we aimed to investigate the molecular functional role of miR-23a in colorectal carcinogenesis. Quantitative real-time polymerase chain reaction was conducted to investigate the expression level of miR-23a in tissue samples and cell lines (HCT116 and SW480). CCK-8, colony formation and Transwell assay were used to explore the role of miR-23a in cell proliferation and migration. Dual luciferase reporter assay was used to identify the direct binding of miR-23a with its target, MARK1. Western blot analysis was used to analyze the expression level of MARK1, as well as a confirmed miR-23a target gene, MTSS1, in miR-23a-mimic and miR-23a-inhibit groups. Rescue experiments were conducted by overexpression of MARK1 in miR-23a-mimic-transfected cell lines. The results showed that miR-23a was highly expressed in colorectal cancer tissue and cell lines. MiR-23a could promote proliferation and migration of colorectal cancer cell lines. MARK1 was a direct target of miR-23a and the expression level of MARK1 was down-regulated in miR-23a-mimic-transfected cell lines but up-regulated in miR-23a-inhibit-transfected cells. Overexpression of MARK1 could partly reverse the cancer-promoting function of miR-23a. Our results suggested that miR-23a promotes colorectal cancer cell proliferation and migration by mediating the expression of MARK1. MiR-23a may be a potential therapeutic target for colorectal cancer treatment.

Serum overexpression of miR-301a and miR-23a in patients with colorectal cancer

BACKGROUND

Extracellular vesicles (EVs) are a heterogeneous group of membrane-bound vesicles with complex cargoes including proteins, lipids, and nucleic acids. EVs have received significant attention due to their specific features including stability under harsh conditions and involvement in cell-to-cell communication. Circulating EVs and the molecules associated with them are important in the diagnosis and prognosis of cancers. MicroRNAs (miRNAs) are a group of small noncoding RNAs that have a role in regulating gene expression. Current literature shows that circulating miRNAs can be used as noninvasive biomarkers for early detection of cancers. The present study was set to investigate the potential role of serum exosomal miRNA expression levels in colorectal cancer (CRC) patients and evaluate their correlation with clinicopathologic features.

METHODS

Exosome-enriched fractions were isolated from the serum of 25 CRC patients and 13 age- and sex-matched healthy controls using a polymer-based precipitation method. During the pilot phase, real-time polymerase chain reaction (RT-PCR) was carried out on 12 CRC patients and eight healthy participants to evaluate the expression difference of 11 candidate miRNAs between CRC patients and tumor free subjects. Finally, the results were validated in a separate group, which was similar in size to the pilot group. The clinicopathologic data were also collected and the relationship between aberrant miRNA expression and clinicopathological parameters were investigated.

RESULTS

There were high expressions of exosomal miR-23a and miR-301a in serum samples of CRC patients compared to normal controls in training and validation phases; these differences were not significantly correlated with clinicopathologic features. Receiver operating characteristic curve analysis showed that miR-301a and miR-23a were able to discriminate CRC patients from normal subjects.

CONCLUSION

The findings provide evidence on the roles of miR-301a and miR-23a in CRC development and their potential roles as noninvasive biomarkers for early detection of CRC.

microRNA-23a in Human Cancer: Its Roles, Mechanisms and Therapeutic Relevance

microRNA-23a (miR-23a) is one of the most extensively studied miRNAs in different types of human cancer, and plays various roles in the initiation, progression, and treatment of tumors. Here, we comprehensively summarize and discuss the recent findings about the role of miR-23a in cancer. The differential expression of tissue miR-23a was reported, potentially indicating cancer stages, angiogenesis, and metastasis. miR-23a in human biofluid, such as plasma and salivary fluid, may be a sensitive and specific marker for early diagnosis of cancer. Tissue and circulating miR-23a serves as a prognostic factor for cancer patient survival, as well as a predictive factor for response to anti-tumor treatment. The direct and indirect regulation of miR-23a on multiple gene expression and signaling transduction mediates carcinogenesis, tumor proliferation, survival, cell migration and invasion, as well as the response to anti-tumor treatment. Tumor cell-derived miR-23a regulates the microenvironment of human cancer through manipulating both immune function and tumor vascular development. Several transcriptional and epigenetic factors may contribute to the dysregulation of miR-23a in cancer. This evidence highlights the essential role of miR-23a in the application of cancer diagnosis, prognosis, and treatment.

Epigenetic Regulation by lncRNAs: An Overview Focused on UCA1 in Colorectal Cancer

Colorectal cancers have become the second leading cause of cancer-related deaths. In particular, acquired chemoresistance and metastatic lesions occurring in colorectal cancer are a major challenge for chemotherapy treatment. Accumulating evidence shows that long non-coding (lncRNAs) are involved in the initiation, progression, and metastasis of cancer. We here discuss the epigenetic mechanisms through which lncRNAs regulate gene expression in cancer cells. In the second part of this review, we focus on the role of lncRNA Urothelial Cancer Associated 1 (UCA1) to integrate research in different types of cancer in order to decipher its putative function and mechanism of regulation in colorectal cancer cells. UCA1 is highly expressed in cancer cells and mediates transcriptional regulation on an epigenetic level through the interaction with chromatin modifiers, by direct regulation via chromatin looping and/or by sponging the action of a diversity of miRNAs. Furthermore, we discuss the role of UCA1 in the regulation of cell cycle progression and its relation to chemoresistance in colorectal cancer cells.

Circulating serum oncologic miRNA in pediatric juvenile pilocytic astrocytoma patients predicts mural nodule volume

BACKGROUND

Juvenile pilocytic astrocytomas represent the largest group of pediatric brain tumors. The ideal management for these tumors is early, total surgical resection. To detect and track treatment response, a screening tool is needed to identify patients for surgical evaluation and assess the quality of treatment. The identification of aberrant miRNA profiles in the sera of juvenile pilocytic astrocytoma patients could provide such a screening tool.

METHODS

The authors reviewed the serum profiles of 84 oncologically relevant miRNAs in pediatric juvenile pilocytic astrocytoma patients via qPCR screening.

RESULTS

miR-21, miR-15b, miR-23a, and miR-146b were significantly elevated in the sera of JPA patients as compared to non-oncologic controls, oncologic controls, and post-JPA resection samples (p < 0.001, 0.022, 0.034, 0.044). miR-21 had the highest AUC on ROC analysis (AUC > 0.99, sensitivity 75%, specificity 100%). All four miRNAs also correlated well with tumor mural nodule size, though they only poorly correlated with total tumor size, including cystic components (Spearman's R²: miR-21 91.7 vs 6.9%, miR-15b 86.3 vs 23.1%, miR-23a 85.8 vs 23.0%, miR-146b 59.8 vs 11.9%).

CONCLUSION

In this small pilot study, pediatric juvenile pilocytic astrocytoma patients had significant elevations in serum miR-21, miR-15b, miR-23a, and miR-146b levels that do not appear to be driven by hydrocephalus or local distortion of the intracranial contents. These alterations correlate with solid tumor component volume and reverse with complete tumor resection, suggesting that this serum miRNA profile may delineate biomarkers for screening and tracking juvenile pilocytic astrocytoma patients. Additional studies, with a larger cohort, are needed to verify these results.

miR‑23a suppresses pancreatic cancer cell progression by inhibiting PLK‑1 expression

The present study aimed to explore the effects and underlying mechanisms of microRNA (miR)‑23a on pancreatic cancer (PC) cells progression. Reverse transcription‑quantitative polymerase chain reaction and western blot analysis were used to detect the mRNA and protein miR‑23a and PLK‑1 level. Cell viability, cell cycle, migration and invasion assasy, and in vivo tumorigenicity assay were used to investigate the effects of miR‑204. Further luciferase reporter assay was used to explore the mechanisms contributing to miR‑204 effects. It was observed that miR‑23a expression was upregulated and negatively associated with polo‑like kinase‑1 (PLK‑1) expression in human PC tissues. PLK‑1 was a direct target of miR‑23a in PC cells. Functional analysis demonstrated that miR‑23a overexpression suppressed cell proliferation, inhibited cell migration and invasion and promoted cell apoptosis in vitro. When PC cells were transfected with has‑miR‑23a PLK‑1 was downregulated and its downstream molecules were deregulated, including decreased expression of B‑cell lymphoma‑2, cyclin B1 and vimentin, and increased expression of Bax and E‑cadherin. The inhibitory effect of miR‑23a on PC cell progression was observed in vivo tumor xenografts. The results of the study suggest that miR‑23a inhibits PC cell progression by directly targeting PLK‑1‑associated signaling and promoting miR‑23a expression may be a potential method for treating patients with PC.

Asymmetric RNA Distribution among Cells and Their Secreted Exosomes: Biomedical Meaning and Considerations on Diagnostic Applications

Over the past few years, exosomes and their RNA cargo have been extensively studied because of the fascinating biological roles they play in cell-to-cell communication, including the signal exchange among cancer, stromal, and immune cells, leading to modifications of tumor microenvironment. RNAs, especially miRNAs, stored within exosomes, seem to be among the main determinants of such signaling: their sorting into exosomes appears to be cell-specific and related to cellular physiopathology. Accordingly, the identification of exosomal miRNAs in body fluids from pathological patients has become one of the most promising activity in the field of biomarker discovery. Several analyses on the qualitative and quantitative distribution of RNAs between cells and their secreted exosomes have given rise to questions on whether and how accurately exosomal RNAs would represent the transcriptomic snapshot of the physiological and pathological status of secreting cells. Although the exact molecular mechanisms of sorting remain quite elusive, many papers have reported an evident asymmetric quantitative distribution of RNAs between source cells and their exosomes. This phenomenon could depend both on passive and active sorting mechanisms related to: (a) RNA turnover; (b) maintaining the cytoplasmic miRNA:target equilibrium; (c) removal of RNAs not critical or even detrimental for normal or diseased cells. These observations represent very critical issues in the exploitation of exosomal miRNAs as cancer biomarkers. In this review, we will discuss how much the exosomal and corresponding donor cell transcriptomes match each other, to better understand the actual reliability of exosomal RNA molecules as pathological biomarkers reflecting a diseased status of the cells.

MiR-23a modulates X-linked inhibitor of apoptosis-mediated autophagy in human luminal breast cancer cell lines

Autophagy is a conserved multi-step lysosomal process that is induced by diverse stimuli including cellular nutrient deficiency. X-linked inhibitor of apoptosis (XIAP) promotes cell survival and recently has been demonstrated to suppress autophagy. Herein, we examined regulation of XIAP-mediated autophagy in breast cancer cells and determined the underlying molecular mechanism. To investigate this process, autophagy of breast cancer cells was induced by Earle's balanced salt solution (EBSS). We observed discordant expression of XIAP mRNA and protein in the autophagic process induced by EBSS, suggesting XIAP may be regulated at a post-transcriptional level. By scanning several miRNAs potentially targeting XIAP, we observed that forced expression of miR-23a significantly decreased the expression of XIAP and promoted autophagy, wherever down-regulation of miR-23a increased XIAPexpression and suppressed autophagy in breast cancer cells. XIAP was confirmed as a direct target of miR-23a by reporter assay utilizing the 3'UTR of XIAP. In vitro, forced expression of miR-23a promoted autophagy, colony formation, migration and invasion of breast cancer cell by down-regulation of XIAP expression. However, miR-23a inhibited apoptosis of breast cancer cells independent of XIAP. Xenograft models confirmed the effect of miR-23a on expression of XIAP and LC3 and that miR-23a promoted breast cancer cell invasiveness. Therefore, our study demonstrates that miR-23a modulates XIAP-mediated autophagy and promotes survival and migration in breast cancer cells and hence provides important new insights into the understanding of the development and progression of breast cancer.

Lentivirus-mediated miR-23a overexpression induces trophoblast cell apoptosis through inhibiting X-linked inhibitor of apoptosis

Preeclampsia (PE) is a pregnancy-specific disorder representing a major cause of maternal and perinatal morbidity and mortality. MicroRNAs (miRNAs) have emerged as critical regulators in PE. However, the precise role of miRNAs in PE remains poorly understood. In this study, we aimed to investigate the potential role of miR-23a and the underlying mechanism in regulating trophoblast cell apoptosis. We found a significant increase of miR-23a expression in placental tissues from PE patients. Lentivirus-mediated miR-23a overexpression significantly induced apoptosis in trophoblast cells in vitro. X-linked inhibitor of apoptosis (XIAP) was identified as a target gene of miR-23a by bioinformatics analysis and dual-luciferase reporter assay. Overexpression of miR-23a significantly inhibited XIAP expression. Knockdown of XIAP also induced trophoblast cell apoptosis. Moreover, restoration of XIAP expression significantly abolished the miR-23 overexpression-induced trophoblast cell apoptosis. Taken together, our study demonstrates that miR-23a induces trophoblast cell apoptosis by inhibiting XIAP, which may contribute to PE. Our findings provide novel insights into understanding the pathogenesis of PE and suggest a potential therapeutic target in PE.

MicroRNAs: Potential candidates for diagnosis and treatment of colorectal cancer

Colorectal cancer (CRC) is known as the third common cancer worldwide and an important public health problem in different populations. Several genetics and environmental risk factors are involved in the development and progression of CRC including chromosomal abnormalities, epigenetic alterations, and unhealthy lifestyle. Identification of risk factors and biomarkers could lead to a better understanding of molecular pathways involved in CRC pathogenesis. MicroRNAs (miRNAs) are important regulatory molecules which could affect a variety of cellular and molecular targets in CRC. A large number of studies have indicated deregulations of some known tissue-specific miRNAs, for example, miR-21, miR-9, miR-155, miR-17, miR-19, let-7, and miR-24 as well as circulating miRNAs, for example, miR-181b, miR-21, miR-183, let-7g, miR-17, and miR-126, in patients with CRC. In the current review, we focus on the findings of preclinical and clinical studies performed on tissue-specific and circulating miRNAs as diagnostic biomarkers and therapeutic targets for the detection of patients at various stages of CRC.

Positive radionuclide imaging of miRNA expression using RILES and the human sodium iodide symporter as reporter gene is feasible and supports a protective role of miRNA-23a in response to muscular atrophy

MicroRNAs (miRNAs) are key players in many biological processes and are considered as an emerging class of pharmacology drugs for diagnosis and therapy. However to fully exploit the therapeutic potential of miRNAs, it is becoming crucial to monitor their expression pattern using medical imaging modalities. Recently, we developed a method called RILES, for RNAi-Inducible Luciferase Expression System that relies on an engineered regulatable expression system to switch-ON the expression of the luciferase gene when a miRNA of interest is expressed in cells. Here we investigated whether replacing the luciferase reporter gene with the human sodium iodide symporter (hNIS) reporter gene will be also suited to monitor the expression of miRNAs in a clinical setting context. We provide evidence that radionuclide imaging of miRNA expression using hNIS is feasible although it is not as robust as when the luciferase reporter gene is used. However, under appropriate conditions, we monitored the expression of several miRNAs in cells, in the liver and in the tibialis anterior muscle of mice undergoing muscular atrophy. We demonstrated that radiotracer accumulation in transfected cells correlated with the induction of hNIS and with the expression of miRNAs detected by real time PCR. We established the kinetic of miRNA-23a expression in mice and demonstrated that this miRNA follows a biphasic expression pattern characterized by a loss of expression at a late time point of muscular atrophy. At autopsy, we found an opposite expression pattern between miRNA-23a and one of the main transcriptional target of this miRNA, APAF-1, and as downstream target, Caspase 9. Our results report the first positive monitoring of endogenously expressed miRNAs in a nuclear medicine imaging context and support the development of additional work to establish the potential therapeutic value of miRNA-23 to prevent the damaging effects of muscular atrophy.

Diagnostic and Therapeutic Potential of Exosomes in Cancer: The Beginning of a New Tale?

Exosomes have emerged as one of the main players in intercellular communication. These small nano-sized particles have many roles in various physiological pathways in normal and abnormal cells. Exosomes can carry various cargos such as proteins, mRNAs, and miRNAs to recipient cells. Uptake of exosomes and their cargo can induce and/or inhibit different cellular and molecular pathways that lead to the alteration of cell behavior. Multiple lines of evidence have indicated that exosomes released from cancer cells can effect development of cancer in different stages. These particles and their cargo could regulate different processes such as tumor growth, metastasis, drug resistance, angiogenesis, and immune system functioning. It has been observed that exosomes can be used as potential diagnostic biomarkers in various cancer types. Moreover, some studies have used these particles as biological vehicles for delivery of various drugs such as doxorubicin, siRNAs, and miRNAs. Here, we summarized the findings on the role of exosomes in different pathological processes involved in cancer. Moreover, application of these particles as diagnostic and therapeutic biomarkers in different types of cancers is discussed. J. Cell. Physiol. 232: 3251-3260, 2017. © 2016 Wiley Periodicals, Inc.

Overexpression of miRNA-221 promotes cell proliferation by targeting the apoptotic protease activating factor-1 and indicates a poor prognosis in ovarian cancer

MicroRNAs are a class of small non-coding, endogenous RNAs involved in cancer development and progression. MicroRNA-221 (mir-221) has been reported to have both an oncogenic and tumor-suppressive role in human tumors, but the role of miR-221 in ovarian cancer is poorly understood. In the present study, the expression levels of miR-221 and the apoptosis protease activating factor 1 (APAF1) protein in 63 samples of ovarian cancer tissues and the cell lines, IOSE25, A2780, OVCAR3, SKOV3 and 3AO were detected by quantitative reverse-transcription polymerase chain reaction (qRT-PCR) and western blot analysis, respectively. Cell proliferation was measured using Cell Counting kit-8 (CCK-8); cell migration and invasion were detected using a Transwell assay; cell apoptosis was evaluated by flow cytometry and Hoechst staining, and a luciferase assay was performed to verify a putative target site of miR-221 in the 3′-UTR of APAF1 mRNA. Expression of miR-221 was upregulated in ovarian cancer tissues. Patients with increased miR-221 expression levels had a reduced disease-free survival (P=0.0014) and overall survival (P=0.0058) compared with those with low miR-221 expression. Transfection of SKOV3 and A2780 cell lines with miR-221 inhibitor induced APAF1 protein expression, suppressed cell proliferation and migration and promoted tumor cell apoptosis. In conclusion, the APAF1 gene was confirmed as a direct target of miR-221 and overexpression of APAF1 suppressed ovarian cancer cell proliferation and induced cell apoptosis in vitro. These findings indicate that miR-221-APAF1 should be studied further as a potential new diagnostic or prognostic biomarker for ovarian cancer.

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

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

Mitochondrial permeabilization without caspase activation mediates the increase of basal apoptosis in cells lacking Nrf2

Nuclear factor E2-related factor-2 (Nrf2) is a cap'n'collar/basic leucine zipper (b-ZIP) transcription factor which acts as sensor of oxidative and electrophilic stress. Low levels of Nrf2 predispose cells to chemical carcinogenesis but a dark side of Nrf2 function also exists because its unrestrained activation may allow the survival of potentially dangerous damaged cells. Since Nrf2 inhibition may be of therapeutic interest in cancer, and a decrease of Nrf2 activity may be related with degenerative changes associated with aging, it is important to investigate how the lack of Nrf2 function activates molecular mechanisms mediating cell death. Murine Embryonic Fibroblasts (MEFs) bearing a Nrf2 deletion (Nrf2KO) displayed diminished cellular growth rate and shortened lifespan compared with wild-type MEFs. Basal rates of DNA fragmentation and histone H2A.X phosphorylation were higher in Nrf2KO MEFs, although steady-state levels of reactive oxygen species were not significantly increased. Enhanced rates of apoptotic DNA fragmentation were confirmed in liver and lung tissues from Nrf2KO mice. Apoptosis in Nrf2KO MEFs was associated with a decrease of Bcl-2 but not Bax levels, and with the release of the mitochondrial pro-apoptotic factors cytochrome c and AIF. Procaspase-9 and Apaf-1 were also increased in Nrf2KO MEFs but caspase-3 was not activated. Inhibition of XIAP increased death in Nrf2KO but not in wild-type MEFs. Mitochondrial ultrastructure was also altered in Nrf2KO MEFs. Our results support that Nrf2 deletion produces mitochondrial dysfunction associated with mitochondrial permeabilization, increasing basal apoptosis through a caspase-independent and AIF-dependent pathway.

MicroRNAs as growth regulators, their function and biomarker status in colorectal cancer

Gene expression is in part regulated by microRNAs (miRNAs). This review summarizes the current knowledge of miRNAs in colorectal cancer (CRC); their role as growth regulators, the mechanisms that regulate the miRNAs themselves and the potential of miRNAs as biomarkers. Although thousands of tissue samples and bodily fluids from CRC patients have been investigated for biomarker potential of miRNAs (>160 papers presented in a comprehensive tables), none single miRNA nor miRNA expression signatures are in clinical use for this disease. More than 500 miRNA-target pairs have been identified in CRC and we discuss how these regulatory nodes interconnect and affect signaling pathways in CRC progression.

Oncogenic miR-23a in Pancreatic Ductal Adenocarcinogenesis Via Inhibiting APAF1

BACKGROUND

miR-23a, which participates in invasion of pancreatic ductal adenocarcinoma cells into the mesothelial barrier, is a critical regulator in many cancers. It, however, is still unknown whether miR-23a regulates pancreatic cell proliferation and apoptosis or not.

AIMS

We sought to investigate the role of miR-23a in regulation of pancreatic cell proliferation and apoptosis.

METHODS

miRNA, mRNA, and protein expressions were determined by qRT-PCR and Western blot, respectively. Dual-luciferase reporter assay was used in detection for binding ability of miR-23a to APAF1. Ectopic miR-23a and APAF 1 were introduced to pancreatic cells, and their roles in proliferation and apoptosis were detected by MTT, colony formation, and apoptosis assays, respectively.

RESULTS

Up-regulation of miR-23a and down-regulation of APAF 1 were found in pancreatic ductal cancer, respectively. miR-23a significantly inhibited the luciferase activity by targeting APAF 1 3'UTR. Ectopic miR-23a significantly suppressed the APAF 1 gene expression in pancreatic cancer cells. Similar to siAPAF1, miR-23a significantly promoted pancreatic cancer cell proliferation and repressed apoptosis. Furthermore, miR-23a inhibitor and exogenous APAF 1 could recover the effects.

CONCLUSIONS

It is suggested that miR-23a, acting as an oncogenic regulator by directly targeting APAF 1 in pancreatic cancer, is a useful potential biomarker in diagnosis and treatment of pancreatic cancer.

Oncogenic miR-23a in Pancreatic Ductal Adenocarcinogenesis Via Inhibiting APAF1

BACKGROUND

miR-23a, which participates in invasion of pancreatic ductal adenocarcinoma cells into the mesothelial barrier, is a critical regulator in many cancers. It, however, is still unknown whether miR-23a regulates pancreatic cell proliferation and apoptosis or not.

AIMS

We sought to investigate the role of miR-23a in regulation of pancreatic cell proliferation and apoptosis.

METHODS

miRNA, mRNA, and protein expressions were determined by qRT-PCR and Western blot, respectively. Dual-luciferase reporter assay was used in detection for binding ability of miR-23a to APAF1. Ectopic miR-23a and APAF 1 were introduced to pancreatic cells, and their roles in proliferation and apoptosis were detected by MTT, colony formation, and apoptosis assays, respectively.

RESULTS

Up-regulation of miR-23a and down-regulation of APAF 1 were found in pancreatic ductal cancer, respectively. miR-23a significantly inhibited the luciferase activity by targeting APAF 1 3'UTR. Ectopic miR-23a significantly suppressed the APAF 1 gene expression in pancreatic cancer cells. Similar to siAPAF1, miR-23a significantly promoted pancreatic cancer cell proliferation and repressed apoptosis. Furthermore, miR-23a inhibitor and exogenous APAF 1 could recover the effects.

CONCLUSIONS

It is suggested that miR-23a, acting as an oncogenic regulator by directly targeting APAF 1 in pancreatic cancer, is a useful potential biomarker in diagnosis and treatment of pancreatic cancer.

High microRNA-23a expression in laryngeal squamous cell carcinoma is associated with poor patient prognosis

Background

MicroRNA-23a (miR-23a) has been demonstrated to play an important role in the development of several types of cancer, but its role in tumorigenesis of laryngeal carcinoma is still unclear. The aim of this study was to investigate the expression patterns and clinical implications of miR-23a in laryngeal cancer.

Methods

Quantitative RT-PCR was performed to evaluate the expression level of miR-23a in 52 pairs of laryngeal cancer. Analysis between miR-23a expression and clinical features of laryngeal carcinomas was performed by appropriate statistical methods. Role of miR-23a in laryngeal cancer cell migration and invasion was detected via transwell and matrigel assays, respectively.

Results

miR-23a was significantly up-regulated in laryngeal cancer tissues compared to normal adjacent laryngeal tissues (P < 0.01). Tumors with high miR-23a expression had significantly greater extent of lymph node metastasis (P < 0.01), worse clinical stage (P < 0.05) and shorter overall five-year survival (P < 0.01) than those with low miR-23a expression. Both univariate and multivariate Cox hazard regression analysis results showed that clinical stage and miR-23a expression were significantly correlated with patient five-year survival (P < 0.01). miR-23a overexpression also significantly promoted laryngeal cancer cell migration and invasion in vitro.

Conclusions

miR-23a, an independent prognostic factor for laryngeal cancer, participates in the onset and progression of laryngeal cancer.

Virtual slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/2021488014982305