Down-regulation of 5S rRNA by miR-150 and miR-383 enhances c-Myc-rpL11 interaction and inhibits proliferation of esophageal squamous carcinoma cells

MicroRNA copy number alterations in the malignant transformation of pleomorphic adenoma to carcinoma ex pleomorphic adenoma

OBJECTIVE

This study used array comparative genomic hybridization to assess copy number alterations (CNAs) involving miRNA genes in pleomorphic adenoma (PA), recurrent pleomorphic adenoma (RPA), residual PA, and carcinoma ex pleomorphic adenoma (CXPA).

MATERIALS AND METHODS

We analyzed 13 PA, 4 RPA, 29 CXPA, and 14 residual PA using Nexus Copy Number Discovery software. The miRNAs genes affected by CNAs were evaluated based on their expression patterns and subjected to pathway enrichment analysis.

RESULTS

Across the groups, we found 216 CNAs affecting 2261 miRNA genes, with 117 in PA, 59 in RPA, 846 in residual PA, and 2555 in CXPA. The chromosome 8 showed higher involvement in altered miRNAs in PAs and CXPA patients. Six miRNA genes were shared among all groups. Additionally, miR-21, miR-455-3p, miR-140, miR-320a, miR-383, miR-598, and miR-486 were prominent CNAs found and is implicated in carcinogenesis of several malignant tumors. These miRNAs regulate critical signaling pathways such as aerobic glycolysis, fatty acid biosynthesis, and cancer-related pathways.

CONCLUSION

This study was the first to explore CNAs in miRNA-encoding genes in the PA-CXPA sequence. The findings suggest the involvement of numerous miRNA genes in CXPA development and progression by regulating oncogenic signaling pathways.

The Pol III transcriptome: Basic features, recurrent patterns, and emerging roles in cancer

The RNA polymerase III (Pol III) transcriptome is universally comprised of short, highly structured noncoding RNA (ncRNA). Through RNA-protein interactions, the Pol III transcriptome actuates functional activities ranging from nuclear gene regulation (7SK), splicing (U6, U6atac), and RNA maturation and stability (RMRP, RPPH1, Y RNA), to cytoplasmic protein targeting (7SL) and translation (tRNA, 5S rRNA). In higher eukaryotes, the Pol III transcriptome has expanded to include additional, recently evolved ncRNA species that effectively broaden the footprint of Pol III transcription to additional cellular activities. Newly evolved ncRNAs function as riboregulators of autophagy (vault), immune signaling cascades (nc886), and translation (Alu, BC200, snaR). Notably, upregulation of Pol III transcription is frequently observed in cancer, and multiple ncRNA species are linked to both cancer progression and poor survival outcomes among cancer patients. In this review, we outline the basic features and functions of the Pol III transcriptome, and the evidence for dysregulation and dysfunction for each ncRNA in cancer. When taken together, recurrent patterns emerge, ranging from shared functional motifs that include molecular scaffolding and protein sequestration, overlapping protein interactions, and immunostimulatory activities, to the biogenesis of analogous small RNA fragments and noncanonical miRNAs, augmenting the function of the Pol III transcriptome and further broadening its role in cancer. This article is categorized under: RNA in Disease and Development > RNA in Disease RNA Processing > Processing of Small RNAs RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications.

Circ_0005231 promotes the progression of esophageal squamous cell carcinoma via sponging miR-383-5p and regulating KIAA0101

Background

Circular RNAs (circRNAs) can act as key regulators in human cancers, including esophageal squamous cell carcinoma (ESCC). However, the role and mechanism of circ_0005231 in ESCC have not previously been reported.

Methods

RNA levels and protein levels were detected by real‐time quantitative polymerase chain reaction (RT‐qPCR) and Western blot assay, respectively. Cell proliferation was assessed by colony formation assay and 5‐ethynyl‐2'‐deoxyuridine (EdU) assay. Wound healing and transwell assays were used to assess cell migration and invasion, respectively. The intermolecular interaction was predicted by bioinformatic analysis and verified by RNA immunoprecipitation (RIP), RNA pulldown and dual‐luciferase reporter assays. Xenograft tumor model was used for exploring the biological function of circ_0005231 in vivo.

Results

Circ_0005231 was upregulated in ESCC plasma, tissues and cells. Cell proliferation, migration and invasion were significantly restrained by knockdown of circ_0005231 in ESCC cells. Circ_0005231 acted as a sponge of miR‐383‐5p, and circ_0005231 regulated ESCC cellular behavior by sponging miR‐383‐5p. Moreover, miR‐383‐5p directly targeted KIAA0101, and circ_0005231 positively regulated KIAA0101 expression by sponging miR‐383‐5p. Furthermore, circ_0005231 knockdown suppressed the malignant behavior of ESCC cells by downregulating KIAA0101. Importantly, knockdown of circ_0005231 blocked xenograft tumor growth in vivo.

Conclusion

Circ_0005231 acted as a sponge of miR‐383‐5p to promote ESCC progression by upregulating KIAA0101, which provided a potential therapeutic strategy for ESCC treatment.

A Concise Review of MicroRNA-383: Exploring the Insights of Its Function in Tumorigenesis

MicroRNAs (miRNAs) are small noncoding RNAs that commonly have 18-22 nucleotides and play important roles in the regulation of gene expression via directly binding to the 3'-UTR of target mRNAs. Approximately 50% of human genes are regulated by miRNAs and they are involved in many human diseases, including various types of cancers. Recently, microRNA-383 (miR-383) has been identified as being aberrantly expressed in multiple cancers, such as malignant melanoma, colorectal cancer, hepatocellular cancer, and glioma. Increasing evidence suggests that miR-383 participates in tumorigenic events including proliferation, apoptosis, invasion, and metastasis as well as drug resistance. Although downstream targets including CCND1, LDHA, VEGF, and IGF are illustrated to be regulated by miR-383, its roles in carcinogenesis are still ambiguous and the underlying mechanisms are still unclear. Herein, we review the latest studies on miR-383 and summarize its functions in human cancers and other diseases. The goal of this review is to provide new strategies for targeted therapy and further investigations.

MicroRNA-383: A tumor suppressor miRNA in human cancer

Downregulated expression of anti-tumor miR-383 has been found in many kinds of cancer. MiR-383 family members can directly target the 3'-untranslated region (3'-UTR) of the mRNA of some pro-tumor genes to attenuate several cancer-related processes, including cell proliferation, invasion, migration, angiogenesis, immunosuppression, epithelial-mesenchymal transition, glycolysis, chemoresistance, and the development of cancer stem cells, whilst promoting apoptosis. Functionally, miR-383 operates as a tumor inhibitor miRNA in many types of cancer, including breast cancer, hepatocellular carcinoma, gastric cancer, pancreatic cancer, colorectal cancer, esophageal cancer, lung cancer, head and neck cancer, glioma, medulloblastoma, melanoma, prostate cancer, cervical cancer, oral squamous cell carcinoma, thyroid cancer, and B-cell lymphoma. Both pro-tumor and anti-tumor effects have been attributed to miR-383 in ovarian cancer. However, only the pro-tumor effects of miR-383 were reported in cholangiocarcinoma. The restoration of miR-383 expression could be considered a possible treatment for cancer. This review discusses the anti-tumor effects of miR-383 in human cancers, emphasizing their downstream target genes and potential treatment approaches.

Novel Implications of MicroRNAs, Long Non-coding RNAs and Circular RNAs in Drug Resistance of Esophageal Cancer

Esophageal cancer is the eighth most common malignancy and the sixth leading cause of cancer-related deaths worldwide. Chemotherapy based on platinum drugs, 5-fluorouracil, adriamycin, paclitaxel, gemcitabine, and vinorelbine, as well as targeted treatment and immunotherapy with immune checkpoint inhibitors improved the prognosis in a portion of patients with advanced esophageal cancer. Unfortunately, a number of esophageal cancer patients develop drug resistance, resulting in poor outcomes. Multiple mechanisms contributing to drug resistance of esophageal cancer have been reported. Notably, non-coding RNAs (ncRNAs), including microRNAs (miRNAs), long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs), have been identified to play crucial roles in modulating esophageal cancer drug resistance. In the present review, we highlight the underlying mechanisms how miRNAs, lncRNAs, and circRNAs impact the drug resistance of esophageal cancer. Several miRNAs, lncRNAs, and circRNAs may have potential clinical implications as novel biomarkers and therapeutic targets for esophageal cancer.

Hypoxic naked mole-rat brains use microRNA to coordinate hypometabolic fuels and neuroprotective defenses

Naked mole-rats are among the mammalian champions of hypoxia tolerance. They evolved adaptations centered around reducing metabolic rate to overcome the challenges experienced in their underground burrows. In this study, we used next-generation sequencing to investigate one of the factors likely supporting hypoxia tolerance in naked mole-rat brains, posttranscriptional microRNAs (miRNAs). Of the 212 conserved miRNAs identified using small RNA sequencing, 18 displayed significant differential expression during hypoxia. Bioinformatic enrichment revealed that hypoxia-mediated miRNAs were suppressing energy expensive processes including de novo protein translation and cellular proliferation. This suppression occurred alongside the activation of neuroprotective and neuroinflammatory pathways, and the induction of central signal transduction pathways including HIF-1α and NFκB via miR-335, miR-101, and miR-155. MiRNAs also coordinated anaerobic glycolytic fuel sources, where hypoxia-upregulated miR-365 likely suppressed protein levels of ketohexokinase, the enzyme responsible for catalyzing the first committed step of fructose catabolism. This was further supported by a hypoxia-mediated reduction in glucose transporter 5 proteins that import fructose into the cell. Yet, messenger RNA and protein levels of lactate dehydrogenase, which converts pyruvate to lactate in the absence of oxygen, were elevated during hypoxia. Together, this demonstrated the induction of anaerobic glycolysis despite a lack of reliance on fructose as the primary fuel source, suggesting that hypoxic brains are metabolically different than anoxic naked mole-rat brains that were previously found to shift to fructose-based glycolysis. Our findings contribute to the growing body of oxygen-responsive miRNAs "OxymiRs" that facilitate natural miRNA-mediated mechanisms for successful hypoxic exposures.

MeCP2 facilitates breast cancer growth via promoting ubiquitination-mediated P53 degradation by inhibiting RPL5/RPL11 transcription

Methyl-CpG-binding protein 2 (MeCP2) facilitates the carcinogenesis and progression of several types of cancer. However, its role in breast cancer and the relevant molecular mechanism remain largely unclear. In this study, analysis of the Cancer Genome Atlas (TCGA) data that MeCP2 expression was significantly upregulated in breast cancer tissues, and high MeCP2 expression was correlated with poor overall survival. Knockdown of MeCP2 inhibited breast cancer cell proliferation and G1–S cell cycle transition and migration as well as induced cell apoptosis in vitro. Moreover, MeCP2 knockdown suppressed cancer cell growth in vivo. Investigation of the molecular mechanism showed that MeCP2 repressed RPL11 and RPL5 transcription by binding to their promoter regions. TCGA data revealed significantly lower RPL11 and RPL5 expression in breast cancer tissues; additionally, overexpression of RPL11/RPL5 significantly suppressed breast cancer cell proliferation and G1–S cell cycle transition and induced apoptosis in vitro. Furthermore, RPL11 and RPL5 suppressed ubiquitination-mediated P53 degradation through direct binding to MDM2. This study demonstrates that MeCP2 promotes breast cancer cell proliferation and inhibits apoptosis through suppressing RPL11 and RPL5 transcription by binding to their promoter regions.

MicroRNA-383 inhibits doxorubicin resistance in hepatocellular carcinoma by targeting eukaryotic translation initiation factor 5A2

Drug resistance occurs commonly in cancers, especially in hepatocellular carcinoma (HCC). Accumulating evidence has demonstrated that microRNAs (miRNAs) play a vital role in tumour chemoresistance. However, little is known about the role of miR-383 in HCC chemoresistance. In the present study, RT-PCR and western blotting were used to identify the expression profile of miR-383 and eukaryotic translation initiation factor 5A2 (EIF5A2). The bioinformatics website Targetscan was used to predict the target genes of miR-383. In vitro and in vivo loss- and gain-of-function studies were performed to reveal the effects and potential mechanism of the miR-383/EIF5A2 axis in chemoresistance of HCC cells. The expression level of miR-383 correlated negatively with doxorubicin (Dox) sensitivity. Overexpression of miR-383 promoted HCC cells to undergo Dox-induced cytotoxicity and apoptosis, whereas miR-383 knockdown had the opposite effects. EIF5A2 was predicted as a target gene of miR-383. EIF5A2 knockdown sensitized HCC cells to Dox. Moreover, miR-383 inhibition-mediated HCC Dox resistance could be reversed by silencing EIF5A2. Finally, we demonstrated that miR-383 inhibition could enhance Dox sensitivity by targeting EIF5A2 in vivo. The results indicated that miR-383 inhibited Dox resistance in HCC cells by targeting EIF5A2. Targeting the miR-383/EIF5A2 axis might help to alleviate the chemoresistance of HCC cells.

microRNA-383 regulates cell viability and apoptosis by mediating Wnt/β-catenin signaling pathway in non-small cell lung cancer

The aim of this study was to investigate the roles of microRNA-383 (miRNA-383) in progression of non-small cell lung cancer (NSCLC) and the potential mechanism. The expressions of miR-383 and Wnt1 protein were detected in lung cancer tissues and cells by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot analysis. After the transfection of miR-383 mimics, si-Wnt1 or miR-383+Wnt1, the viability and apoptosis of NSCLC cells were detected by cell counting kit-8 and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling, respectively. The interaction between miR-383 and Wnt1 was investigated by luciferase activity and Western blot analysis. Cells stably transfected with miR-383 mimics were inoculated into the right axillary of nude mice by subcutaneous injection. The tumor volume and weight were measured, and the expressions of miR-383, Wnt1, β-catenin, and cyclin D1 were detected by qRT-PCR and Western blot analysis. The expression of miR-383 was significantly decreased, and the level of Wnt1 was significantly increased (P < 0.05) in lung cancer tissues and cells. Upregulation of miR-383 or inhibition of Wnt1 expression inhibited the cell viability and induce apoptosis in NSCLC cells. Moreover, Wnt1 was the target gene of miR-383, and its overexpression weakened the regulatory effect of miR-383 on cell viability and apoptosis in NSCLC cells. Besides, the addition of miR-383 decreased the tumor volume and size and inhibited the expressions of Wnt1, β-catenin, and cyclin D1 at the protein level in nude mice. Collectively, miR-383 induced apoptosis and inhibited cell viability as well as tumorigenic capacity in nude mice via regulating the Wnt/β-catenin signaling pathway.

The roles of moonlight ribosomal proteins in the development of human cancers

"Moonlighting protein" is a term used to define a single protein with multiple functions and different activities that are not derived from gene fusions, multiple RNA splicing, or the proteolytic activity of promiscuous enzymes. Different proteinous constituents of ribosomes have been shown to have important moonlighting extra-ribosomal functions. In this review, we introduce the impact of key moonlight ribosomal proteins and dependent signal transduction in the initiation and progression of various cancers. As a future perspective, the potential role of these moonlight ribosomal proteins in the diagnosis, prognosis, and development of novel strategies to improve the efficacy of therapies for human cancers has been suggested.

Long non-coding RNA MIAT competitively binds miR-150-5p to regulate ZEB1 expression in osteosarcoma

Long non-coding RNAs (LncRNAs), are significant in a number of biological stages and illnesses. The myocardial infarction associated transcript (MIAT) serves a function in numerous types of illness and physiological and pathological processes, including paranoid schizophrenia, diabetic retinopathy, myocardial infarction and neuroendocrine prostate cancer. However, the function of the lncRNA MIAT in the development of osteosarcoma is unknown. It has been identified that during the development of osteosarcoma, MIAT is upregulated in tumor tissues compared to adjacent non-tumor tissues. The spreading and proliferation of osteosarcoma cells was reduced by MIAT knockdown. These findings indicate that MIAT functions by competing with critical RNAs to target miR-150-5p and activate zinc finger E-box binding homeobox 1 to modulate the function of osteosarcoma cells. Together, the present findings may contribute to the understanding of the pathogenesis of osteosarcoma.

Expression of microRNA-150 and its Target Gene IGF2BP1 in Human Osteosarcoma and their Clinical Implications

Previous study revealed that microRNA (miR)-150 might function as a tumor suppressor in osteosarcoma partially by targeting Insulin-Like Growth Factor 2 mRNA-Binding Protein 1 (IGF2BP1). The aim of this study was to investigate the clinical significance of miR-150-IGF2BP1 axis in human osteosarcoma which remains unclear. At first, expression levels of miR-150, and IGF2BP1 mRNA and protein in 20 osteosarcoma and matched adjacent noncancerous tissues were respectively detected by quantitative real-time PCR and western blot analyses. Then, subcellular localization and expression pattern of IGF2BP1 protein in 100 osteosarcoma tissues were examined by immunohistochemistry. Associations of miR-150/IGF2BP1 expression with various clinicopathological features and patients’ prognosis were also statistically evaluated. As a result, miR-150 expression was significantly decreased, while IGF2BP1 mRNA and protein expression were dramatically increased in osteosarcoma tissues compared to matched adjacent noncancerous tissues (all P < 0.001). Immunostaining of IGF2BP1 protein was localized in cytoplasm of tumor cells in osteosarcoma tissues. Statistically, low miR-150 expression and/or high IGF2BP1 protein immunoreactive score were all significantly associated with high tumor grade, presence of metastasis and recurrence, as well as poor response to chemotherapy (all P < 0.05). Moreover, miR-150, IGF2BP1 and combined miR-150/IGF2BP1 expressions were all identified as independent prognostic factors for overall and disease-free survivals of osteosarcoma patients (all P < 0.05). In conclusion, our data suggest that miR-150 and its downstream target IGF2BP1 may be a crucial axis for the development, progression and patients’ prognosis of ostesarcoma. The newly identified miR-150/IGF2BP1 axis might be a novel potential therapeutic target for osteosarcoma treatment.

miR-383 promotes cholangiocarcinoma cell proliferation, migration, and invasion through targeting IRF1

Interferon regulatory factor 1 (IRF1) has been found to serve as a tumor suppressor in cholangiocarcinoma, and enabled prediction of clinical progression and prognosis in our previous study. The objective of the current study is to screen and identify valuable microRNAs (miR), which target IRF1 to regulate cholangiocarcinoma cell proliferation, migration, and invasion. High expression of miR-383 was observed in cholangiocarcinoma tissues and cells. Meanwhile, we found the predicted binding site of miR-383 on the IRF1 3'-untranslated region (3'-UTR) according to the miR target database. The miR-383 expression was negatively related to IRF1 messeneger RNA (mRNA) and protein expression in cholangiocarcinoma tissue samples, and miR-383 negatively regulated IRF1 mRNA and protein expression in cholangiocarcinoma cells. Subsequently, we conducted a luciferase reporter assay to prove the predicted binding site miR-383 on IRF1 3'-UTR. Moreover, the results of the rescue study suggested that IRF1 was a functional target of miR-383 involved in regulating cholangiocarcinoma cell proliferation, migration, and invasion. Finally, we evaluated the clinical and prognostic significance of miR-383 in cholangiocarcinoma cases, and found that high expression of miR-383 was correlated with advanced tumor stage, large tumor size, present vascular invasion, and metastasis, and acted as an unfavorable independent prognostic factor. In conclusion, miR-383 serves as a tumor-suppressive miR to regulate cholangiocarcinoma cell proliferation, migration, and invasion via directly targeting IRF1.

Mice Expressing Myc in Neural Precursors Develop Choroid Plexus and Ciliary Body Tumors

Choroid plexus tumors and ciliary body medulloepithelioma are predominantly pediatric neoplasms. Progress in understanding the pathogenesis of these tumors has been hindered by their rarity and lack of models that faithfully recapitulate the disease. Here, we find that endogenous Myc proto-oncogene protein is down-regulated in the forebrain neuroepithelium, whose neural plate border domains give rise to the anterior choroid plexus and ciliary body. To uncover the consequences of persistent Myc expression, MYC expression was forced in multipotent neural precursors (nestin-Cre:Myc), which produced fully penetrant models of choroid plexus carcinoma and ciliary body medulloepithelioma. Nestin-mediated MYC expression in the epithelial cells of choroid plexus leads to the regionalized formation of choroid plexus carcinoma in the posterior domain of the lateral ventricle choroid plexus and the fourth ventricle choroid plexus that is accompanied by loss of multiple cilia, up-regulation of protein biosynthetic machinery, and hydrocephalus. Parallel MYC expression in the ciliary body leads also to up-regulation of protein biosynthetic machinery. Additionally, Myc expression in human choroid plexus tumors increases with aggressiveness of disease. Collectively, our findings expose a select vulnerability of the neuroepithelial lineage to postnatal tumorigenesis and provide a new mouse model for investigating the pathogenesis of these rare pediatric neoplasms.

Association of the GLB1 rs4678680 genetic variant with risk of HBV-related hepatocellular carcinoma

Accumulated evidences demonstrated that GLB1 is involved in cell senescence and cancer development. The GLB1 rs4678680 single nucleotide polymorphism (SNP) has been identified as a hepatocellular carcinoma (HCC) susceptibility polymorphism by a genome-wide association study in Korean population previously. However, little or nothing was known about its involvement and functional significance in hepatitis B viruses (HBV)-related HCC in Chinese. Therefore, we investigated the association between the GLB1 rs4678680 SNP and HBV-related HCC risk as well as its biological function in vivo. Genotypes were determined in two independent case-control sets from two medical centers of China. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated by logistic regression. The potential regulation role the rs4678680 genetic variant on GLB1 expression was examined with HCC and normal liver tissues. We found that The rs4678680 G allele was showed to be risk allele; individuals with the TG genotype had an OR of 1.51 (95% CI = 1.10–2.07, P = 0.010, Shandong set) or 1.49 (95% CI = 1.11–1.99, P = 0.008, Jiangsu set) for developing HBV-related HCC, respectively, compared with individuals with the TT genotype. This association was more pronounced in males, individuals aged older than 57 years and drinkers (all P < 0.05). In the genotype-phenotype correlation analyses of fifty-six human liver tissue samples, rs4678680 TG or GG was associated with a statistically significant increase of GLB1 mRNA expression (P < 0.05). Our data indicated that the GLB1 rs4678680 SNP contributes to susceptibility to develop HBV-related HCC, highlighting the involvement of GLB1 and cell senescence in etiology of HCC.

Targeting of miR-150 on Gli1 gene to inhibit proliferation and cell cycle of esophageal carcinoma EC9706

OBJECTIVE

Glioma-associated oncogene homolog 1 (Gli1) in Hedgehog signal pathway regulates Cyclin D1 expression, cell cycle or proliferation modulation. Esophageal cancer patients had significantly elevated Gli1 expression, which is related with survival and prognosis. It has been demonstrated that the level of miR-150 was decreased in esophageal cancer patients compared to normal control. As a complementary relationship exists between miR-150 and 3'-UTR of Gli1, this study investigated if miR-150 played a role in regulating Gli1 expression, and proliferation or cell cycle of esophageal cancer cells.

PATIENTS AND METHODS

Esophageal squamous cell carcinoma (ESCC) patients from our hospital were recruited to collect tumor and adjacent tissues for miR-150 and Gli1 expression. Esophageal carcinoma cell line EC9706 and normal esophageal epithelial cell line HEEC were compared for expression of miR-150, Gli1 and Cyclin D1. Dual luciferase reporter gene assay examined the targeted relationship between miR-150 and 3'-UTR of Gli1. In vitro cultured EC9706 cells were treated with miR-150 mimic, si-Gli1 or the combination of miR-150 mimic and si-Gli1, respectively, to check their gene expression, cell cycle and proliferation.

RESULTS

ESCC tissues had significantly higher Gli1 expression and lower miR-150 expression. EC9706 cell also had higher Gli1 expression than that in HEEC, whilst miR-150 was down-regulated. Via targeting 3'-UTR of Gli1 gene, miR-150 inhibited its expression. Transfection of miR-150 mimic, si-Gli1 or the combination of miR-150 mimic and si-Gli1, respectively, remarkably decreased expression of Gli1 and Cyclin D1 expression in EC9706 cells, whose cell cycle arresting at G0/G1 phase was enhanced with weakened proliferation.

CONCLUSIONS

MiR-150 can induce G0/G1 cell cycle arresting and weaken proliferation of esophageal carcinoma cells via targeted inhibition on Gli1 and downstream expression of Cyclin D1.

MiR-150 Inhibits Cell Growth In Vitro and In Vivo by Restraining the RAB11A/WNT/β-Catenin Pathway in Thyroid Cancer

Background

Emerging evidence has shown that downregulation or upregulation of microRNAs (miRNAs) plays an important role in the development and progression of thyroid cancer (TC). However, the potential role of miR-150 and its biological function in TC remains largely unclear.

Material/Methods

Real-time polymerase chain reaction (RT-qPCR) was employed to detect the expression level of miR-150 and RAB11A in human TC tissue and human normal thyroid tissue. MTT assay, colony formation assay, flow cytometry cell cycle, and apoptosis assay were used to investigate the role of miR-150 and RAB11A on the malignant phenotypes in vitro. Nude mouse xenograft assay and western blot assay was used to verify the function of miR-150 in vivo. Western blot assay and immunofluorescence assay were used to detect the activation of WNT/β-catenin pathway mediated by miR-150 and RAB11A. EGFP reporter assay, RT-qPCR assay, and western blot assay were used to validate the regulation relationship.

Results

This study demonstrated that miR-150 expression in human TC tissues was markedly downregulated. Moreover, overexpression of miR-150 markedly inhibited cell proliferation via inducing the cell cycle arrest and promoting cell apoptosis by directly targeting RAB11A in vitro and suppressing tumor growth in vivo. However, overexpression of RAB11A promoted cell malignant phenotypes. In addition, miR-150 restrained the RAB11A mediated WNT/β-catenin activation in TC cells.

Conclusions

miR-150 may function as a suppressor gene in TC cells by inhibiting the RAB11A/WNT/β-catenin pathway.

Regulation of SPOCK1 by dual strands of pre-miR-150 inhibit cancer cell migration and invasion in esophageal squamous cell carcinoma

Analysis of our microRNA (miRNA) expression signatures of human cancers based on RNA sequencing have shown that both strands of pre-miR-150, miR-150-5p (the guide strand) and miR-150-3p (the passenger strand), are significantly reduced in cancer tissues. We have investigated the functional significance of both strands of pre-miR-150 in cancer cells. The aim of this study was to investigate the antitumor function of these miRNAs and how these miRNAs regulated oncogenic targets in esophageal squamous cell carcinoma (ESCC). Ectopic expression studies demonstrated that both strands of pre-miR-150 miRNA inhibited ESCC cancer cell migration and invasion, indicating that both miR-150-5p and miR-150-3p acted as antitumor miRNAs. A combination of genome-wide gene expression analyses and in silico database searches showed that SPOCK1 (SPARC/osteonectin, cwcv and kazal-like domains proteoglycan 1) was a candidate target of miR-150-5p and miR-150-3p in ESCC cells. Luciferase reporter assays showed that SPOCK1 was directly regulated by these miRNAs. Silencing of SPOCK1 by small interfering RNA inhibited cancer cell migration and invasion. Overexpression of SPOCK1/SPOCK1 was confirmed by real-time PCR methods and immunohistochemistry. Taken together, downregulation of both strands of pre-miR-150 and overexpression of SPOCK1 are involved in ESCC pathogenesis. The involvement of passenger strand miRNAs in the regulation of cancer cell aggressiveness is a novel concept in RNA research.

Redox Regulating Enzymes and Connected MicroRNA Regulators Have Prognostic Value in Classical Hodgkin Lymphomas

There are no previous studies assessing the microRNAs that regulate antioxidant enzymes in Hodgkin lymphomas (HLs). We determined the mRNA levels of redox regulating enzymes peroxiredoxins (PRDXs) I–III, manganese superoxide dismutase (MnSOD), nuclear factor erythroid-derived 2-like 2 (Nrf2), and Kelch-like ECH-associated protein 1 (Keap1) from a carefully collected set of 41 classical HL patients before receiving any treatments. The levels of redoxmiRs, miRNAs known to regulate the above-mentioned enzymes, were also assessed, along with CD3, CD20, and CD30 protein expression. RNAs were isolated from freshly frozen lymph node samples and the expression levels were analyzed by qPCR. mir23b correlated inversely with CD3 and CD20 expressions (p = 0.00076; r = −0.523 and p = 0.0012; r = −0.507) and miR144 with CD3, CD20, and CD30 (p = 0.030; r = −0.352, p = 0.041; r = −0.333 and p = 0.0032; r = −0.47, resp.). High MnSOD mRNA levels associated with poor HL-specific outcome in the patients with advanced disease (p = 0.045) and high miR-122 levels associated with worse HL-specific survival in the whole patient population (p = 0.015). When standardized according to the CD30 expression, high miR212 and miR510 predicted worse relapse-free survival (p = 0.049 and p = 0.0058, resp.). In conclusion, several redoxmiRs and redox regulating enzyme mRNA levels associate with aggressive disease outcome and may also produce prognostic information in classical HL.

Ribosomal Proteins Control or Bypass p53 during Nucleolar Stress

The nucleolus is the site of ribosome biogenesis, a complex process that requires the coordinate activity of all three RNA polymerases and hundreds of non-ribosomal factors that participate in the maturation of ribosomal RNA (rRNA) and assembly of small and large subunits. Nevertheless, emerging studies have highlighted the fundamental role of the nucleolus in sensing a variety of cellular stress stimuli that target ribosome biogenesis. This condition is known as nucleolar stress and triggers several response pathways to maintain cell homeostasis, either p53-dependent or p53-independent. The mouse double minute (MDM2)-p53 stress signaling pathways are activated by multiple signals and are among the most important regulators of cellular homeostasis. In this review, we will focus on the role of ribosomal proteins in p53-dependent and p53-independent response to nucleolar stress considering novel identified regulators of these pathways. We describe, in particular, the role of ribosomal protein uL3 (rpL3) in p53-independent nucleolar stress signaling pathways.

Identification of reference genes and miRNAs for qRT-PCR in human esophageal squamous cell carcinoma

It is important to select an appropriate reference gene and miRNA when using quantitative real-time polymerase chain reaction (qRT-PCR) to analyze gene and miRNA expression. However, many commonly used reference genes and miRNAs are not stably expressed and therefore not suitable for normalization or quantification of qRT-PCR data. This study aims to identify appropriate reference genes and miRNAs for use in human esophageal squamous carcinoma qRT-PCR analysis. Using data provided by The Cancer Genome Atlas, we identified DDX5, LAPTM4A, P4HB, RHOA, miR-28-5p, miR-34a-5p, and miR-186-5p as candidate reference genes and miRNAs. We used qRT-PCR to verify the expression levels of these candidates and another seven commonly used reference genes and miRNAs. A set of 50 paired human normal esophageal tissues and squamous cell carcinoma samples were used in the analysis. We then used geNorm and NormFinder to analyze the results. DDX5, LAPTM4A, RHOA, ACTB, RNU48, miR-28-5p, miR-34a-5p, and miR-186-5p were stably expressed, indicating they are suitable for used as references in qRT-PCR analysis of esophageal squamous cell carcinoma. However, expression levels of 18s rRNA, GAPDH, P4HB, 5s rRNA, U6, and RNU6B varied greatly between esophageal normal and squamous cell carcinoma samples, indicating that they are not suitable for use as references in the qRT-PCR analysis of esophageal squamous cell carcinoma.

Identifying reproducible cancer-associated highly expressed genes with important functional significances using multiple datasets

Identifying differentially expressed (DE) genes between cancer and normal tissues is of basic importance for studying cancer mechanisms. However, current methods, such as the commonly used Significance Analysis of Microarrays (SAM), are biased to genes with low expression levels. Recently, we proposed an algorithm, named the pairwise difference (PD) algorithm, to identify highly expressed DE genes based on reproducibility evaluation of top-ranked expression differences between paired technical replicates of cells under two experimental conditions. In this study, we extended the application of the algorithm to the identification of DE genes between two types of tissue samples (biological replicates) based on several independent datasets or sub-datasets of a dataset, by constructing multiple paired average gene expression profiles for the two types of samples. Using multiple datasets for lung and esophageal cancers, we demonstrated that PD could identify many DE genes highly expressed in both cancer and normal tissues that tended to be missed by the commonly used SAM. These highly expressed DE genes, including many housekeeping genes, were significantly enriched in many conservative pathways, such as ribosome, proteasome, phagosome and TNF signaling pathways with important functional significances in oncogenesis.