miR-21 regulates tumor progression through the miR-21-PDCD4-Stat3 pathway in human salivary adenoid cystic carcinoma

Lnc NBAT1 Inhibits the Proliferation and Migration of Liver Cancer Cells Through the miR-21/PDCD4/AP-1 Signaling Axis

Long non-coding RNAs (Lnc RNAs) are proven to participate in liver cancer (LC) regulation. The regulation of miR-21 by lnc NBAT1 has been studied in other cancers. However, the effect of this regulation on LC and its specific mechanism remains unclear. Lnc NBAT1 and miR-21 expressions in clinical tissues were measured by RT-qPCR. PDCD4, AP-1, p-c-Fos, p-c-Jun, and cyclin D1 expressions were analyzed by Western blot. Overexpression of lnc NBAT1 was studied to explore its influence on malignant behaviors of Bel7402 cells and the development of LC in the xenograft mouse model (XMM). The regulation mechanism of lnc NBAT1 in LC was explored by lnc NBAT1 overexpression, miR-21 mimic treatment, or PDCD4 silencing in Bel7402 cells. Lnc NBAT1 expression was downregulated while miR-21 expression was upregulated in LC tissues and cell lines. In comparison with LX-2 cells, the expressions of PDCD4 and AP-1 were downregulated in Bel7402 cells, while those of p-c-Fos, p-c-Jun, and cyclin D1 were upregulated. Further, lnc NBAT1 was found to localize primarily in the cytoplasm of Bel7402 cells. Overexpression of lnc NBAT1 enhanced cell apoptosis, blocked the cell cycle, suppressed malignant behaviors of Bel7402 cells, and inhibited tumor progression in the XMM. Mechanistically, lnc NBAT1 functioned as a competing endogenous RNA (ceRNA) by binding to the downstream target miR-21 to stabilize the expressions of PDCD4 and AP-1, thereby inhibiting malignant behaviors of Bel7402 cells. Lnc NBAT1 suppressed malignant behaviors of LC cells through the miR-21/PDCD4/AP-1 axis. Lnc NBAT1 might be a promising biomarker for LC treatment.

Engineering supramolecular dynamics of self-assembly and turnover of oncogenic microRNAs to drive their synergistic destruction in tumor models

Rationally-engineered functional biomaterials offer the opportunity to interface with complex biology in a predictive, precise, yet dynamic way to reprogram their behaviour and correct shortcomings. Success here may lead to a desired therapeutic effect against life-threatening diseases, such as cancer. Here, we engineered "Crab"-like artificial ribonucleases through coupling of peptide and nucleic acid building blocks, capable of operating alongside and synergistically with intracellular enzymes (RNase H and AGO2) for potent destruction of oncogenic microRNAs. "Crab"-like configuration of two catalytic peptides ("pincers") flanking the recognition oligonucleotide was instrumental here in providing increased catalytic turnover, leading to ≈30-fold decrease in miRNA half-life as compared with that for "single-pincer" conjugates. Dynamic modeling of miRNA cleavage illustrated how such design enabled "Crabs" to drive catalytic turnover through simultaneous attacks at different locations of the RNA-DNA heteroduplex, presumably by producing smaller cleavage products and by providing toeholds for competitive displacement by intact miRNA strands. miRNA cleavage at the 5'-site, spreading further into double-stranded region, likely provided a synergy for RNase H1 through demolition of its loading region, thus facilitating enzyme turnover. Such synergy was critical for sustaining persistent disposal of continually-emerging oncogenic miRNAs. A single exposure to the best structural variant (Crab-p-21) prior to transplantation into mice suppressed their malignant properties and reduced primary tumor volume (by 85 %) in MCF-7 murine xenograft models.

Dynamic Role of miRNAs in Salivary Gland Carcinomas: From Biomarkers to Therapeutic Targets

BACKGROUND

Salivary gland carcinomas (SGCs) are a rare group of malignant neoplasms of the head and neck region. MicroRNAs (miRNAs) are a class of small non-coding RNAs that have been associated with the control biological process and oncogenic mechanism by the regulation of gene expression at the post-transcriptional level. Recent evidence has suggested that miRNA expression may play a role in the tumorigenesis and carcinogenesis process in SGCs.

METHODS

This review provides a comprehensive literature review of the role of miRNAs expression in SGCs focusing on the diagnostic, prognostic, and therapeutic applications.

RESULTS

In this review, numerous dysregulated miRNAs have demonstrated an oncogenic and suppressor role in SGCs.

CONCLUSION

In the future, these miRNAs may eventually constitute useful diagnostic and prognostic biomarkers that may lead to a better understanding of SGCs oncogenesis. Additionally, the development of therapeutic agents based on miRNAs may be a promising target in SGC treatment.

The effects of intracellular and exosomal ncRNAs on cancer progression

Altered gene expression as well as mislocalization of a gene's encoded product (proteins or noncoding RNAs (ncRNAs)) can lead to disease and cancer formation. Multiple studies have indicated that exosomes and their contents act as cell-to-cell communicators and play a key role in cancer progression. Moreover, exosomes contain several functional molecules, including ncRNAs. NcRNAs function as master regulators to coordinate cell growth, cell motility and drug resistance. However, intracellular ncRNAs, which can be transferred to recipient cells via exosomes (exosomal ncRNAs), mediate common/distinct downstream molecules, signaling pathways and functions that are less emphasized concepts in cancer development research. In this study, by using exosomes as a model, we comprehensively discuss the current knowledge regarding (1) the functional role of ncRNAs, both their intracellular and exosomal forms, in cancer progression, (2) the possible mechanism of ncRNA incorporation into exosomes and (3) the therapeutic applications and limitations of exosomes based on current knowledge.

miRNAs orchestration of salivary gland cancer- Particular emphasis on diagnosis, progression, and drug resistance

Cancer of the salivary glands is one of the five major types of head and neck cancer. Due to radioresistance and a strong propensity for metastasis, the survival rate for nonresectable malignant tumors is dismal. Hence, more research is needed on salivary cancer's pathophysiology, particularly at the molecular level. The microRNAs (miRNAs) are a type of noncoding RNA that controls as many as 30% of all genes that code for proteins at the posttranscriptional level. Signature miRNA expression profiles have been established in several cancer types, suggesting a role for miRNAs in the incidence and progression of human malignancies. Salivary cancer tissues were shown to have significantly aberrant levels of miRNAs compared to normal salivary gland tissues, supporting the hypothesis that miRNAs play a crucial role in the carcinogenesis of salivary gland cancer (SGC). Besides, several SGC research articles reported potential biomarkers and therapeutic targets for the miRNA-based treatment of this malignancy. In this review, we will explore the regulatory impact of miRNAs on the processes underlying the molecular pathology of SGC and provide an up-to-date summary of the literature on miRNAs that impacted this malignancy. We will eventually share information about their possible use as diagnostic, prognostic, and therapeutic biomarkers in SGC.

Circulating miR-21 Overexpression Correlates with PDCD4 and IL-10 in Systemic Lupus Erythematosus (SLE): A Promising Diagnostic and Prognostic Biomarker

Background

Systemic Lupus Erythematosus (SLE) is a chronic autoimmune condition that affects multiple organs significantly impacts morbidity and mortality. The development of SLE is influenced by genetic predisposition and dysregulated immune response. Our objective was to investigate miR-21, IL-10, and PDCD4 expression in SLE patient plasma and analyze their correlations and potential diagnostic and prognostic values.

Methods

The study included 100 healthy subjects, 50 newly diagnosed (ND), and 50 under-treatment (UT) SLE patients. The patients were observed for 24 weeks to track relapses. miR-21 and PDCD4 gene expression levels were measured using real-time RT-PCR, and IL-10 production was measured using ELISA.

Results

miR-21 and IL-10 expression levels were significantly greater in SLE patients than in healthy subjects, with the highest levels observed in ND patients. PDCD4 expression was also significantly greater in SLE patients than in subjects, with the highest levels observed in UT patients. ROC curve analyses and Cox-Mantel Log-rank tests indicated miR-21, PDCD4, and IL-10 as proper diagnostic and prognostic biomarkers for SLE. The study also revealed a significant positive correlation between miR-21 and PDCD4 and IL-10 levels in SLE patients.

Conclusions

The studies suggest that dysregulation of miR-21, PDCD4, and IL-10 in patients with SLE may contribute to disease development and provides new diagnostic and prognostic markers. Additionally, the observed correlation between miR-21, PDCD4, and IL-10 levels in SLE patients signifies a potential interplay between these molecules.

Identification of MicroRNA Expression Profiles Related to the Aggressiveness of Salivary Gland Adenoid Cystic Carcinomas

Adenoid cystic carcinoma (ACC) has been reported as the second most common carcinoma of the salivary glands. Few studies have associated miRNA expression with ACC aggressiveness. In this study, we evaluated the miRNA profile of formalin-fixed, paraffin-embedded (FFPE) samples of salivary gland ACC patients using the NanoString platform. We studied the miRNA expression levels associated with the solid growth pattern, the more aggressive histologic feature of ACCs, compared with the tubular and cribriform growth patterns. Moreover, the perineural invasion status, a common clinicopathological feature of the disease that is frequently associated with the clinical progression of ACC, was investigated. The miRNAs showing significant differences between the study groups were selected for target prediction and functional enrichment, which included associations with the disease according to dedicated databases. We observed decreased expression of miR-181d, miR-23b, miR-455, miR-154-5p, and miR-409 in the solid growth pattern compared with tubular and cribriform growth patterns. In contrast, miR-29c, miR-140, miR-195, miR-24, miR-143, and miR-21 were overexpressed in patients with perineural invasion. Several target genes of the miRNAs identified have been associated with molecular processes involved in cell proliferation, apoptosis, and tumor progression. Together, these findings allowed the characterization of miRNAs potentially associated with aggressiveness in salivary gland adenoid cystic carcinoma. Our results highlight important new miRNA expression profiles involved in ACC carcinogenesis that could be associated with the aggressive behavior of this tumor type.

The potential role of miRNAs in the pathogenesis of salivary gland cancer - A Focus on signaling pathways interplay

Salivary gland cancer (SGC) is immensely heterogeneous, both in terms of its physical manifestation and its aggressiveness. Developing a novel diagnostic and prognostic detection method based on the noninvasive profiling of microribonucleic acids (miRs) could be a goal for the clinical management of these specific malignancies, sparing the patients' valuable time. miRs are promising candidates as prognostic biomarkers and therapeutic targets or factors that can advance the therapy of SGC due to their ability to posttranscriptionally regulate the expression of various genes involved in cell proliferation, differentiation, cell cycle, apoptosis, invasion, and angiogenesis. Depending on their biological function, many miRs may contribute to the development of SGC. Therefore, this article serves as an accelerated study guide for SGC and the biogenesis of miRs. Here, we shall list the miRs whose function in SGC pathogenesis has recently been determined with an emphasis on their potential applications as therapeutic targets. We will also offer a synopsis of the current state of knowledge about oncogenic and tumor suppressor miRs in relation to SGC.

HCG11 inhibits salivary adenoid cystic carcinoma by upregulating EphA2 via binding to miR-1297

OBJECTIVE

Ephrin receptor A2 (EphA2) was reported to be related to the tumorigenesis of salivary adenoid cystic carcinoma (SACC), which is a rare malignancy accounting for less than 1% of all oral and maxillofacial tumors. This research aimed to assess the molecular mechanisms of EphA2 in SACC.

STUDY DESIGN

The expression of long non-coding RNA human leukocyte antigen complex group 11 (HCG11), microRNA-1297 (miR-1297), and EphA2 in SACC cell lines compared with normal human salivary gland (HSG) cell line was measured by reverse transcription-quantitative polymerase chain reaction. EphA2 protein level was detected by western blot. 5-ethynyl-2'-deoxyuridine (EdU), colony formation, Transwell, and wounding healing experiments were applied to evaluate SACC cell proliferation, migration, and invasion. The relationship among HCG11, miR-1297, and EphA2 was confirmed by luciferase reporter, RNA pulldown, and RNA immunoprecipitation experiments.

RESULTS

HCG11 and EphA2 were downregulated while miR-1297 was upregulated in SACC cells. EphA2 overexpression suppressed SACC cell proliferation, migration, and invasion. HCG11 bound to miR-1297 to reduce the inhibition of miR-1297 on EphA2 expression. EphA2 knockdown reversed the suppression of HCG11 overexpression on SACC cell phenotypes.

CONCLUSION

This study identified the HCG11/miR-1297/EphA2 regulatory axis in SACC, which might provide novel therapeutic targets for SACC.

Interactive role of miR-29, miR-93, miR-205, and VEGF in salivary adenoid cystic carcinoma

OBJECTIVES

Salivary adenoid cystic carcinoma (SACC) is one of the most common salivary gland tumors in which patients encounter local recurrence and lung metastases. Understanding prognostic biomarkers in SACC is essential for future development in prognosis and treatment. This study aimed to assess the expression level of vascular endothelial growth factor (VEGF) and its potential regulatory microRNAs in SACC for prognostic determination. MATERIAL AND METHODS: The expression of VEGF in SACC samples was assessed using immunohistochemistry. Potential regulatory microRNAs were evaluated using quantitative reverse transcription-polymerase chain reaction. Associations between VEGF and microRNAs expression and clinicopathological parameters were investigated.

RESULTS

VEGF expression levels positively correlated with histologic grade (p = .004) and treatment modality (p = .04). Decreased expression of miR-29a (p = .01) and increased expression of miR-93-5p and miR-205 (both p < .0001) were observed in SACC compared to normal salivary gland tissue. MiR-93-5p showed a positive association (p = .02) with VEGF overexpression.

CONCLUSIONS

Our results showed the downregulation of miR-29 and overexpression of miR-93 and miR-205 in the SACC group, and the correlation between miR-93 and VEGF suggests these biomarkers as potential prognostic markers in the future.

The imminent role of microRNAs in salivary adenoid cystic carcinoma

Unfortunately, despite the severe problem associated with salivary adenoid cystic carcinoma (SACC), it has not been studied in detail yet. Therefore, the time has come to understand the oncogenic cause of SACC and find the correct molecular markers for diagnosis, prognosis, and therapeutic target to tame this disease. Recently, we and others have suggested that non-coding RNAs, specifically microRNAs and long non-coding RNAs, can be ideal biomarkers for cancer(s) diagnosis and progression. Herein, we have shown that various miRNAs, like miR-155, miR‑103a‑3p, miR-21, and miR-130a increase the oncogenesis process, whereas some miRNAs such as miR-140-5p, miR-150, miR-375, miR-181a, miR-98, miR-125a-5p, miR-582-5p, miR-144-3p, miR-320a, miR-187 and miR-101-3p, miR-143-3p inhibit the salivary adenoid cystic carcinoma progression. Furthermore, we have found that miRNAs also target many vital genes and pathways like mitogen-activated protein kinases-snail family transcriptional repressor 2 (MAPK-Snai2), p38/JNK/ERK, forkhead box C1 protein (FOXC1), mammalian target of rapamycin (mTOR), integrin subunit beta 3 (ITGB3), epidermal growth factor receptor (EGFR)/NF-κB, programmed cell death protein 4 (PDCD4), signal transducer and activator of transcription 3 (STAT3), neuroblastoma RAS (N-RAS), phosphatidylinositol-3-kinase (PI3K)/Akt, MEK/ERK, ubiquitin-like modifier activating enzyme 2 (UBA2), tumor protein D52 (TPD52) which play a crucial role in the regulation of salivary adenoid cystic carcinoma. Therefore, we believe that knowledge from this manuscript will help us find the pathogenesis process in salivary adenoid cystic carcinoma and could also give us better biomarkers of diagnosis and prognosis of the disease.

Artificial primary-miRNAs as a platform for simultaneous delivery of siRNA and antisense oligonucleotide for multimodal gene regulation

Self-assembled nucleic acid nanostructures have been widely explored for gene therapy applications due to their unique advantages. Their roles are not limited to offer intracellular delivery platforms but additionally provide a biological function to induce targeted gene regulation. Here, we report a self-assembled artificial primary-miRNA (pri-miRNA) for achieving simultaneous multimodal gene regulation. Artificial pri-miRNAs are designed to play a role as substrate RNAs to recruit and interact with Drosha/DGCR8 (Microprocessor). Incorporation of functional RNA motifs and site-specific chemical modification of the primary miRNA are utilized for the biogenesis of two individual gene-regulating oligonucleotides. Once they are cleaved by the endogenous Drosha/DGCR8 complex, basal strands and pre-miRNA can be generated inside of cells. In this study, we integrated basal strands with either SMN2 ASO or anti-miR21 to induce multimodal gene regulation. Microprocessing and subsequent gene regulation were first evaluated by measuring the activity of reporter pre-miRNA. Chemical modification on the primary miRNA was optimized through a series of in vitro Drosha cleavage tests and targeted gene silencing in cells. Primary miRNA with the basal ASO or anti-miR strands showed a successful in vitro activity and resulted in simultaneous multimodal gene regulation in cells. Artificial primary miRNA may offer synergistic therapeutic effects for treating various diseases, including spinal muscular atrophy and cancer.

The multifaceted role of STAT3 pathway and its implication as a potential therapeutic target in oral cancer

Oral cancer is one of the leading causes of cancer-related deaths, and it has become a matter of serious concern due to the alarming rise in its incidence rate worldwide. Despite recent advancements in oral cancer treatment strategies, there are no significant improvements in patient's survival rate. Among the numerous cell signaling pathways involved in oral cancer development and progression, STAT3 is known to play a multifaceted oncogenic role in shaping the tumor pathophysiology. STAT3 hyperactivation in oral cancer contributes to survival, proliferation, invasion, epithelial to mesenchymal transition, metastasis, immunosuppression, chemoresistance, and poor prognosis. A plethora of pre-clinical and clinical studies have documented the role of STAT3 in the initiation and development of oral cancer and showed that STAT3 inhibition holds significant potential in the prevention and treatment of this cancer. However, to date, targeting STAT3 activation mainly involves inhibiting the upstream signaling molecules such as JAK and IL-6 receptors. The major challenge in targeting STAT3 lies in the complexity of its phosphorylation- and dimerization-independent functions, which are not affected by disrupting the upstream regulators. The present review delineates the significance of the STAT3 pathway in regulating various hallmarks of oral cancer. In addition, it highlights the STAT3 inhibitors identified to date through various preclinical and clinical studies that can be employed for the therapeutic intervention in oral cancer treatment.

Interplay Between Non-Coding RNAs and Programmed Cell Death Proteins

Programmed cell death (PDCD) family of proteins includes at least 12 members, function of seven of them being more investigated. These members are PDCD1, PDCD2, PDCD4, PDCD5, PDCD6, PDCD7 and PDCD10. Consistent with the important roles of these proteins in the regulation of apoptosis, dysregulation of PDCDs is associated with diverse disorders ranging from intervertebral disc degeneration, amyotrophic lateral sclerosis, immune thrombocytopenia, type 1 diabetes, congenital hypothyroidism, Alzheimer’s disease to different types of cancers. More recently, the interaction between non-coding RNAs and different members of PDCD family is being discovered. In the current study, we described the functional interactions between PDCDs and two classes of non-coding RNAs, namely microRNAs (miRNAs) and long non-coding RNAs (lncRNAs). miR-21 and miR-183 are two miRNAs whose interactions with PDCDs have been assessed in different contexts. The lncRNAs interaction with PDCDs is mainly assessed in the context of neoplasia indicating the role of MALAT1, MEG3, SNHG14 and LINC00473 in this process.

Reconstruction and analysis of the aberrant lncRNA-miRNA-mRNA network based on competitive endogenous RNA in adenoid cystic carcinoma of the salivary gland

Background

The aim of this work was to investigate the competing endogenous RNA (ceRNA) network in adenoid cystic carcinoma of the salivary gland (SACC).

Methods

Differentially expressed lncRNAs (DElncRNAs), miRNAs (DEmiRNAs), and mRNAs (DEmRNAs) between cancer tissues and normal salivary gland (NSG) in ACC were identified using data from the Gene Expression Omnibus (GEO) database. Functional annotation and pathway enrichment analysis of DEmRNAs were performed using the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases. The miRNAs that are targeted by lncRNAs were predicted using miRanda and PITA, while the target mRNAs of miRNAs were retrieved from miRanda, miRWalk, and TargetScan. A protein-protein interaction (PPI) network was constructed using the Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) database, and then we constructed the lncRNA-miRNA-mRNA networks of ACC.

Results

Differentially expressed RNAs were identified in SACC. Upon comparing cancer tissues and NSG tissues, 103 upregulated and 52 downregulated lncRNAs and 745 upregulated and 866 downregulated mRNAs were identified in GSE88804; in addition, 39 upregulated and 43 downregulated miRNAs were identified in GSE117275. GO enrichment analyses revealed that the most relevant GO terms were regulation of transcription DNA-templated, transcription DNA-templated, and cell division. KEGG pathway enrichment analysis showed that differentially expressed genes (DEGs) were mainly enriched in the cell cycle, pathways in cancer, PI3K-Akt signaling pathway, breast cancer, and microRNAs in cancer. The PPI network consisted of 27 upregulated and 54 downregulated mRNAs. By constructing ceRNA network, NONHSAT251752.1-hsa-miR-6817-5p-NOTCH1, NONHSAT251752.1-hsa-miR-204-5p/hsa-miR-138-5p-CDK6 regulatory axises were identified and all genes in the network were verified by qRT-PCR.

Conclusions

The present study constructed ceRNA networks in SACC and provided a novel perspective of the molecular mechanisms for SACC.

Current Advances in Coptidis Rhizoma for Gastrointestinal and Other Cancers

Cancer is a serious disease with an increasing number of reported cases and high mortality worldwide. Gastrointestinal cancer defines a group of cancers in the digestive system, e.g., liver cancer, colorectal cancer, and gastric cancer. Coptidis Rhizoma (C. Rhizoma; Huanglian, in Chinese) is a classical Chinese medicinal botanical drug for the treatment of gastrointestinal disorders and has been shown to have a wide variety of pharmacological activity, including antifungal, antivirus, anticancer, antidiabetic, hypoglycemic, and cardioprotective effects. Recent studies on C. Rhizoma present significant progress on its anticancer effects and the corresponding mechanisms as well as its clinical applications. Herein, keywords related to C. Rhizoma, cancer, gastrointestinal cancer, and omics were searched in PubMed and the Web of Science databases, and more than three hundred recent publications were reviewed and discussed. C. Rhizoma extract along with its main components, berberine, palmatine, coptisine, magnoflorine, jatrorrhizine, epiberberine, oxyepiberberine, oxyberberine, dihydroberberine, columbamine, limonin, and derivatives, are reviewed. We describe novel and classic anticancer mechanisms from various perspectives of pharmacology, pharmaceutical chemistry, and pharmaceutics. Researchers have transformed the chemical structures and drug delivery systems of these components to obtain better efficacy and bioavailability of C. Rhizoma. Furthermore, C. Rhizoma in combination with other drugs and their clinical application are also summarized. Taken together, C. Rhizoma has broad prospects as a potential adjuvant candidate against cancers, making it reasonable to conduct additional preclinical studies and clinical trials in gastrointestinal cancer in the future.

Mir-21 Suppression Promotes Mouse Hepatocarcinogenesis

The microRNA 21 (miR-21) is upregulated in almost all known human cancers and is considered a highly potent oncogene and potential therapeutic target for cancer treatment. In the liver, miR-21 was reported to promote hepatic steatosis and inflammation, but whether miR-21 also drives hepatocarcinogenesis remains poorly investigated in vivo. Here we show using both carcinogen (Diethylnitrosamine, DEN) or genetically (PTEN deficiency)-induced mouse models of hepatocellular carcinoma (HCC), total or hepatocyte-specific genetic deletion of this microRNA fosters HCC development-contrasting the expected oncogenic role of miR-21. Gene and protein expression analyses of mouse liver tissues further indicate that total or hepatocyte-specific miR-21 deficiency is associated with an increased expression of oncogenes such as Cdc25a, subtle deregulations of the MAPK, HiPPO, and STAT3 signaling pathways, as well as alterations of the inflammatory/immune anti-tumoral responses in the liver. Together, our data show that miR-21 deficiency promotes a pro-tumoral microenvironment, which over time fosters HCC development via pleiotropic and complex mechanisms. These results question the current dogma of miR-21 being a potent oncomiR in the liver and call for cautiousness when considering miR-21 inhibition for therapeutic purposes in HCC.

MiR-21 in the Cancers of the Digestive System and Its Potential Role as a Diagnostic, Predictive, and Therapeutic Biomarker

MicroRNAs (miRNAs) are small non-coding RNAs. They can regulate the expression of their target genes, and thus, their dysregulation significantly contributes to the development of cancer. Growing evidence suggests that miRNAs could be used as cancer biomarkers. As an oncogenic miRNA, the roles of miR-21 as a diagnostic and prognostic biomarker, and its therapeutic applications have been extensively studied. In this review, the roles of miR-21 are first demonstrated via its different molecular networks. Then, a comprehensive review on the potential targets and the current applications as a diagnostic and prognostic cancer biomarker and the therapeutic roles of miR-21 in six different cancers in the digestive system is provided. Lastly, a brief discussion on the challenges for the use of miR-21 as a therapeutic tool for these cancers is added.

miR-5191 acts as a tumor suppressor in salivary adenoid cystic carcinoma by targeting Notch-2

OBJECTIVE

This study sought to investigate the effect of miR-5191 on proliferation, invasion and metastasis in salivary adenoid cystic carcinoma (SACC).

MATERIALS AND METHODS

The differential expression level of miR-5191 between 5 primary tumor and adjacent non-neoplastic samples, and in two SACC cell lines was detected by quantitative real-time PCR. Cell proliferation, invasion, and migration were performed, followed by luciferase reporter assay and western analysis. The effect of miR-5191 on cell proliferation and apoptosis was evaluated by cell growth and apoptosis assay. The function of miR-5191 in SACC tumorigenesis and metastasis in vivo was investigated by nude mice experiment. The associations between miR-5191/Notch-2 expression and clinicopathological features were analyzed.

RESULTS

miR-5191 was downregulated in primary tumor tissues and SACC-LM cells. By targeting Notch-2, miR-5191 expression level affected the migration, invasion, and proliferation of SACC cells. Overexpression of miR-5191 inhibited the expression levels of Notch-2, followed by the decreased expression of c-Myc, Bcl-2, Hes-1, Hey-1, and Cyclin D1. In vivo, miR-5191 overexpression suppressed the SACC tumorigenesis and pulmonary metastasis in mice. In SACC patients, higher expression of miR-5191 was related to better prognoses and lower possibility of metastasis.

CONCLUSIONS

miR-5191 acts as a tumor suppressor in SACC by targeting Notch-2.

LRRC75A-AS1 targets miR-199b-5p/PDCD4 axis to repress multiple myeloma

BACKGROUND

Multiple functions of miR-199b-5p in diseases have been demonstrated by existing studies. However, never has the correlation between miR-199b-5p and multiple myeloma (MM) been established.

METHODS

qRT-PCR analyzed RNA expression and western blot measured protein expression. Cell proliferation ability was tested via colony formation and EdU assays, and apoptosis was determined via TUNEL, flow cytometry and detection of apoptosis-related proteins. Position of LRRC75A antisense RNA 1 (LRRC75A-AS1) was recognized by FISH assay. RIP, RNA pull-down and luciferase reporter experiments explored the molecular interplay.

RESULTS

GEO (Gene Expression Omnibus) data revealed miR-199b-5p upregulation in MM specimens, and qRT-PCR data verified miR-199b-5p upregulation in MM cells. Inhibiting miR-199b-5p markedly impeded MM cell proliferation and stimulated apoptosis. Moreover, we demonstrated the mechanism that miR-199b-5p was decoyed by LRRC75A-AS1 and miR-199b-5p targeted programmed cell death 4 (PDCD4) to repress its expression. Further, LRRC75A-AS1 was verified to repress proliferation and prompt apoptosis in a PDCD4-dependent way in MM cells.

CONCLUSION

Our data displayed that miR-199b-5p was sequestered by LRRC75A-AS1 so that PDCD4 was released to repress MM, implying the targeting miR-199b-5p as a novel thought for improving MM therapy.

The roles of microRNAs in the stemness of oral cancer cells

Oral cancer (OC), which is the most common form of head and neck cancers, has one of the lowest (~50%) overall 5-year survival rates. The main reasons for this high mortality rate are diagnosis of OC in advanced stages in most patients and spread to distant organs via lymph node metastasis. Many studies have shown that a small population of cells within the tumor plays vital roles in the initiation, progression, and metastasis of the tumor, resistance to chemotherapeutic agents, and recurrence. These cells, identified as cancer stem cells (CSCs), are the main reasons for the failure of current treatment modalities. Deregulated expressions of microRNAs are closely related to tumor prognosis, metastasis and drug resistance. In addition, microRNAs play important roles in regulating the functions of CSCs. Until now, the roles of microRNAs in the acquisition and maintenance of OC stemness have not been elucidated in detail yet. Here in this review, we summarized significant findings and the latest literature to better understand the involvement of CSCs in association with dysregulated microRNAs in oral carcinogenesis. Possible roles of these microRNAs in acquisition and maintenance of CSCs features during OC pathogenesis were summarized.

The potential of circulating exosomal RNA biomarkers in cancer

INTRODUCTION

There are great potentials of using exosomal RNAs (exoRNA) as biomarkers in cancers. The isolation of exoRNA requires the use of ultracentrifugation to isolate cell-free RNA followed by detection using real-time PCR, microarray, next-generation sequencing, or Nanostring nCounter system. The use of exoRNA enrichment panels has largely increased the detection sensitivity and specificity when compared to traditional diagnostic tests. Moreover, using exoRNA as biomarkers can assist the early detection of chemo and radioresistance cancer, and in turn opens up the possibility of personalized treatment to patients. Finally, exoRNA can be detected at an early stage of cancer recurrence to improve the survival rate.

AREAS COVERED

In this review, the authors summarized the detection methods of exoRNA as well as its potential as a biomarker in cancer diagnosis and chemo and radioresistance.

EXPERT OPINION

The application of exoRNAs in clinical diagnosis is still in its infancy. Further researches on extracellular vesicles isolation, detection protocols, exoRNA classes and subclasses, and the regulatory biological pathways have to be performed before exoRNA can be applied translationally.

Role of exosomal miR‑21 in the tumor microenvironment and osteosarcoma tumorigenesis and progression (Review)

Osteosarcoma is the most common bone tumor affecting both adolescents and children. Early detection is critical for the effective treatment of the disease. Derived from cancer cells, miR‑21 contained within exosomes in the tumor microenvironment may act on both cancer cells and the surrounding tumor microenvironment (TME), including immune cells, endothelial cells and fibroblasts. In human serum and plasm, the level of exosomal miR‑21 between osteosarcoma patients and healthy controls differs, supporting the role of miR‑21 as a biomarker for osteosarcoma. The involvement of a number of miR‑21 target genes in tumor progression suggests that miR‑21 may significantly affect the plasticity of cancer cells, leading to tumor progression, metastasis, angiogenesis and immune escape in osteosarcoma. Understanding the biogenesis and functions of exosomal miR‑21 is of great value for the diagnosis and therapy of cancer, including osteosarcoma. The present review discusses the role of miR‑21 in the tumor microenvironment, and in the development and progression of osteosarcoma, with an aim to summarize the functions of this miRNA in cancer.

Transcriptome analyses identify hub genes and potential mechanisms in adenoid cystic carcinoma

Adenoid cystic carcinoma (ACC) is one of the most frequent malignancies of salivary glands. The objective of this study was to identify key genes and potential mechanisms during ACC samples.The gene expression profiles of GSE88804 data set were downloaded from Gene Expression Omnibus. The GSE88804 data set contained 22 samples, including 15 ACC samples and 7 normal salivary gland tissues. The gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were constructed, and protein-protein interaction network of differentially expressed genes (DEGs) was performed by Cytoscape. The top 10 hub genes were analyzed based on Gene Expression Profiling Interactive Analysis. Then, DEGs between ACC samples and normal salivary gland samples were analyzed by gene set enrichment analysis. Furthermore, miRTarBase and Cytoscape were used for visualization of miRNA-mRNA regulatory network. KEGG pathway analysis was undertaken using DIANA-miRPath v3.0.In total, 382 DEGs were identified, including 119 upregulated genes and 263 downregulated genes. GO analysis showed that DEGs were mainly enriched in extracellular matrix organization, extracellular matrix, and calcium ion binding. KEGG pathway analysis showed that DEGs were mainly enriched in p53 signaling pathway and salivary secretion. Expression analysis and survival analysis showed that ANLN, CCNB2, CDK1, CENPF, DTL, KIF11, and TOP2A are all highly expressed, which all may be related to poor overall survival. Predicted miRNAs of 7 hub DEGs mainly enriched in proteoglycans in cancer and pathways in cancer.This study indicated that identified DEGs and hub genes might promote our understanding of molecular mechanisms, which might be used as molecular targets or diagnostic biomarkers for ACC.

Activation of the STAT3/microRNA-21 pathway participates in angiotensin II-induced angiogenesis

Angiotensin II (AngII) facilitates angiogenesis that is associated with the continuous progression of atherosclerotic plaques, but the underlying mechanisms are still not fully understood. Several microRNAs (miRNAs) have been shown to promote angiogenesis; however, whether miRNAs play a crucial role in AngII-induced angiogenesis remains unclear. This study evaluated the functional involvement of miRNA-21 (miR-21) in the AngII-mediated proangiogenic response in human microvascular endothelial cells (HMECs). We found that AngII exerted a proangiogenic role, indicated by the promotion of proliferation, migration, and tube formation in HMECs. Next, miR-21 was found to be upregulated in AngII-treated HMECs, and its specific inhibitor potently blocked the proangiogenic effects of AngII. Subsequently, we focused on the constitutive activation of STAT3 in the AngII-mediated proangiogenic process. Bioinformatic analysis indicated that STAT3 acted as a transcription factor initiating miR-21 expression, which was verified by ChIP-PCR. A reporter assay further identified three functional binding sites of STAT3 in the miR-21 promoter region. Moreover, phosphatase and tensin homolog (PTEN) was recognized as a target of miR-21, and STAT3 inhibition restored AngII-induced reduction in PTEN. Similarly, the STAT3/miR-21 axis was shown to mediate AngII-provoked angiogenesis in vivo, which was demonstrated by using the appropriate inhibitors. Our data suggest that AngII was involved in proangiogenic responses through miR-21 upregulation and reduced PTEN expression, which was, at least in part, linked to STAT3 signaling. The present study provides novel insights into AngII-induced angiogenesis and suggests potential treatment strategies for attenuating the progression of atherosclerotic lesions and preventing atherosclerosis complications.

The Regulatory Role of Non-coding RNAs on Programmed Cell Death Four in Inflammation and Cancer

Programmed cell death 4 (PDCD4) is a tumor suppressor gene implicated in many cellular functions, including transcription, translation, apoptosis, and the modulation of different signal transduction pathways. The downstream mechanisms of PDCD4 have been well-discussed, but its upstream regulators have not been systematically summarized. Noncoding RNAs (ncRNAs) are gene transcripts with no protein-coding potential but play a pivotal role in the regulation of the pathogenesis of solid tumors, cardiac injury, and inflamed tissue. In recent studies, many ncRNAs, especially microRNAs (miRNAs) and long noncoding RNAs (lncRNAs), were found to interact with PDCD4 to manipulate its expression through transcriptional regulation and function as oncogenes or tumor suppressors. For example, miR-21, as a classic oncogene, was identified as the key regulator of PDCD4 by targeting its 3′-untranslated region (UTR) to promote tumor proliferation, migration, and invasion in colon, breast, and bladder carcinoma. Therefore, we reviewed the recently emerging pleiotropic regulation of PDCD4 by ncRNAs in cancer and inflammatory disorders and aimed to shed light on the mechanisms of associated diseases, which could be conducive to the development of novel treatment strategies for PDCD4-induced diseases.

Anti-inflammatory roles of microRNA 21 in lipopolysaccharide-stimulated human dental pulp cells

microRNAs are small noncoding RNA molecules that regulate RNA silencing and posttranscriptional gene expression, and many microRNAs are involved in inflammatory processes. In particular, microRNA 21 (miR-21) is upregulated in inflammatory environment and reported to induce anti-inflammatory responses. However, the involvement of miR-21 in pulpal inflammation and the precise mechanisms of anti-inflammatory reactions induced by miR-21 remain unclear. We hypothesized that miR-21-5p expression is induced in lipopolysaccharide (LPS)-stimulated human dental pulp cells (hDPCs) and that miR-21-5p downregulates the proinflammatory cytokine expression in LPS-stimulated hDPCs. We found that miR-21-5p was upregulated in LPS-stimulated hDPCs concomitant with elevated proinflammatory cytokine expression and nuclear factor-kappa B (NF-κB) phosphorylation. miR-21-5p and cytokine expression were downregulated by BAY11-7085 and caffeic acid phenylethyl ester (CAPE), specific and potent NF-κB inhibitors. Enforced expression of miR-21-5p downregulated the Toll-like receptor (TLR)/NF-κB signaling via reducing the expression of TNF receptor-associated factor 6 (TRAF6) and programmed cell death 4 (PDCD4), which further induced the decrease of proinflammatory cytokine expression. hDPCs forcibly overexpressing miR-21-5p downregulated the LPS-induced expression of TNF receptor-associated factor 6 (TRAF6; a component of the Toll-like receptor [TLR]/NF-κB signaling pathway), programmed cell death 4 (PDCD4, a positive regulator of the TLR/NF-κB signaling pathway), and proinflammatory cytokines. In contrast, miR-21-5p inhibitor-transfected hDPCs upregulated the expression of TRAF6, PDCD4, and inflammatory cytokines following LPS stimulation. These findings suggest that miR-21-5p expression was induced by the NF-κB signaling pathway, which was in turn negatively regulated by miR-21-5p via downregulation of TRAF6 and PDCD4 expression in LPS-stimulated hDPCs.

Ginsenoside Rb1 protects cardiomyocytes from oxygen-glucose deprivation injuries by targeting microRNA-21

Ginsenoside Rb1 (GS-Rb1) is one of the most important active pharmacological extracts of the traditional Chinese medicine, ginseng, and there is extensive evidence of its cardioprotective properties. However, the microRNA (miR) targets of GS-Rb1 and the underlying mechanisms of GS-Rb1 and miR-21 in the progression of cardiomyocyte apoptosis have not been clearly elucidated. The aim of the current study was to investigate the impact of miR-21 and its target gene, programmed cell death protein 4 (PDCD4), on the protective effect of GS-Rb1 in cardiomyocytes injured by oxygen-glucose deprivation (OGD). The miR-21 expression levels were downregulated, and the percentage of the apoptotic cells and reactive oxygen species (ROS) was increased in OGD-cultured neonatal rat cardiomyocytes; however, the effects were reversed by GS-Rb1 treatment. It was demonstrated that GS-Rb1 could reduce intracellular ROS content, and the expression of cytochrome C and the pro-apoptosis protein, apoptosis regulator B-cell lymphoma associated X (Bax) protein while increasing the expression of the anti-apoptosis protein, apoptosis regulator Bcl-2. The target gene, PDCD4, was significantly upregulated in the OGD group; however, the expression of PDCD4 was inhibited by GS-Rb1 treatment. Furthermore, miR-21 inhibitor transfection reduced GS-Rb1-induced miR-21 upregulation compared with the OGD+GS-Rb1 group, indicating that the miR-21 was involved in the anti-apoptotic effect of GS-Rb1 in cardiomyocytes. The results of the current study highlighted that GS-Rb1 could target miR-21 and its target gene, PDCD4, to protect OGD-injured cardiomyocytes. The results of the current study may provide a novel insight for the treatment of myocardial infarction with Traditional Chinese Medicines, involving miRs as targets.

MiR-744-5p inducing cell death by directly targeting HNRNPC and NFIX in ovarian cancer cells

MicroRNAs (miRNAs) play an important role in the regulation of gene expression. The binding to target messenger RNAs (mRNAs) results in mRNA cleavage or inhibition of the translational machinery leading to decreased protein levels. Various signalling pathways, including apoptosis are modulated by miRNAs. Here, we investigated the role of miR-744-5p in apoptosis signalling in ovarian cancer cell lines. MiR-744-5p expression was reduced in the cancer cell lines independent of the host gene MAP2K4. Overexpression of miR-744-5p activated the intrinsic apoptotic pathway in SKOV3, OVCAR3 and Cisplatin resistant (A2780-cis) and non-resistant A2780 cells leading to cell death. Notably, miR-744-5p overexpression together with Carboplatin treatment led to at least additive pro-apoptotic effects. Investigation of the apoptotic signalling pathways mediated by miR-744-5p revealed that its elevated expression directly downregulated mRNA and protein expression of nuclear factor I X (NFIX) and heterogeneous nuclear ribonucleoprotein C (HNRNPC). HNRNPC caused diminished miR-21 expression and AKT phosphorylation, while NFIX decreased Bcl2 levels, leading to the detected pro-apoptotic effects. Finally, Kaplan-Meier-Plots showed a prolonged median disease-free survival in ovarian serous cystadenocarcinoma patients with high miR-744 expression.

Role of miR-21 in the growth and metastasis of human salivary adenoid cystic carcinoma

Aberrant microRNA (miRNA/miR) expression has been reported in various cancer types. miR-21, which is considered to be a proto-oncogene and is frequently overexpressed in certain cancer types, has been implicated in tumorigenesis. The aim of the present study was to investigate the effect of miR-21 degradation on tumor progression and its potential mechanisms in human salivary adenoid cystic carcinoma (SACC) development. Results of reverse transcription-quantitative polymerase chain reaction analysis indicated that SACC cells with high metastatic potential (SACC-LM cells) exhibited a significantly higher expression of miR-21 compared with SACC cells with a lower metastatic potential (SACC-83 cells). In addition, following transfection of SACC-LM cells with miR-21 inhibitor, cell viability was reduced, which may be a result of reduced cell proliferation and metastasis, and the induction of apoptosis, as determined by Cell Counting Kit-8, wound healing, Matrigel invasion and flow cytometry assays. Furthermore, bioinformatics analysis indicated that programmed cell death 4 (PDCD4), phosphatase and tensin homolog deleted on chromosome ten (PTEN) and B-cell lymphoma (Bcl)-2 are potential target genes of miR-21. Therefore, western blotting was performed to investigate the expression of these proteins, and the results demonstrated that miR-21 expression level was negatively associated with PDCD4 and PTEN protein expression, and positively associated with Bcl-2 protein expression, in SACC-LM cells, indicating that miR-21 may promote SACC progression via PDCD4, PTEN and Bcl-2. In conclusion, the present study indicates that miR-21 may be a novel target for SACC therapy and provide a novel basis for the clinical treatment of SACC.

Propofol regulates the expression of TLR4 through miR‑21 in human umbilical vein endothelial cells

Propofol (2,6-diisopropylphenol) is one of the most commonly used intravenous anesthetics. Anesthetics can regulate the inflammatory process; however, the mechanism remains to be fully elucidated. The present study aimed to investigate whether and how propofol affects the inflammatory reaction in human umbilical vein endothelial cells (HUVECs). The expression levels of Toll‑like receptor 4 (TLR4) and cluster of differentiation 14 (CD14) were determined in HUVECs treated with propofol and lipopolysaccharide (LPS) using western blot and reverse transcription‑quantitative polymerase chain reaction analyses. In addition, whether propofol regulated the expression of TLR4 though microRNA (miR)‑21 was examined. The results showed that LPS promoted the expression levels of TLR4, CD14 and tumor necrosis factor α (TNFα), and suppressed the expression of miR‑21 in HUVECs. Propofol suppressed the expression levels of TLR4, CD14 and TNFα, and upregulated the expression of miR‑21 in a concentration‑dependent manner. miR‑21 downregulated the expression of TLR4 at the mRNA and protein levels, whereas the miR‑21 mimic reversed the effect of LPS on the expression of TLR4. In addition, the miR‑21 inhibitor inhibited the downregulatory effect of propofol on the expression of TLR4. TargetScan analysis showed that TLR4 was included in the list of targets of miR‑21. Fluorescent reporter assays showed that the miR‑21 mimic and propofol treatment reduced the fluorescence intensity in cells transfected with a reporter vector containing the wild‑type TLR4 3'‑untranslated region. Taken together, the results of the present study demonstrated that propofol regulated the expression of TLR4 in HUVECs through miR‑21.

MiR21 sensitized B-lymphoma cells to ABT-199 via ICOS/ICOSL-mediated interaction of Treg cells with endothelial cells

BACKGROUND

MicroRNAs (miRs) are involved in tumor progression by regulating tumor cells and tumor microenvironment. MiR21 is overexpressed in diffuse large B-cell lymphoma (DLBCL) and its biological impact on tumor microenvironment remains unclear.

METHODS

MiR21 was assessed by quantitative RT-PCR in patients with newly diagnosed DLBCL. The mechanism of action of miR21 on lymphoma progression and tumor angiogenesis was examined in vitro in B-lymphoma cell lines and in vivo in a murine xenograft model.

RESULTS

Serum miR21 was significantly elevated in patients and associated with advanced disease stage, International Prognostic Index indicating intermediate-high and high-risk, and increased tumor angiogenesis. When co-cultured with immune cells and endothelial cells, miR21-overexpressing B-lymphoma cells were resistant to chemotherapeutic agents, but sensitive to Bcl-2 inhibitor ABT-199, irrespective of Bcl-2 expression on lymphoma cells. In both co-culture systems of Bcl-2^positive and Bcl-2^negative B-lymphoma cells, miR21 induced inducible co-stimulator (ICOS) expression on regulatory T (Treg) cells. Through crosstalking with Treg cells by ICOS ligand (ICOSL), endothelial cells were activated, resulting in stimulation of Bcl-2 expression and vessel formation. ABT-199 directly targeted Bcl-2 on endothelial cells, induced endothelial cell apoptosis and inhibited tumor angiogenesis. In a murine xenograft model established with subcutaneous injection of B-lymphoma cells, ABT-199 particularly retarded the growth of miR21-overexpressing tumors, consistent with the induction of endothelial cell apoptosis and inhibition of tumor angiogenesis.

CONCLUSIONS

As a serum oncogenic biomarker of B-cell lymphoma, miR21 indicated B-lymphoma cell sensitivity to ABT-199 via ICOS/ICOSL-mediated interaction of Treg cells with endothelial cells.

Regulatory effects of berberine on microRNome in Cancer and other conditions

Berberine (BBR) is an isoquinoline alkaloid found in different plant families such as Berberidaceae, Ranunculaceae, and Papaveraceae. BBR is well-known for its anti-inflammatory, lipid-modifying, anticancer, anti-diabetic, antibacterial, antiparasitic and fungicide activities. Multiple pharmacological actions of BBR stem from different molecular targets of this phytochemical. MicroRNAs (miRs) are single-stranded, evolutionary conserved, small non-coding RNA molecules with a length of 19-23 nucleotides that are involved in RNA silencing and post-transcriptional regulation of gene expression through binding to the 3'-untranslated region (3'UTR) of target mRNA. MiRs emerged as important regulatory elements in almost all biological processes like cell proliferation, apoptosis, differentiation and organogenesis, and numerous human diseases such as cancer and diabetes. BBR was shown to regulate the expression of miRs in several diseases. Here, we reviewed the target miRs of BBR and the relevance of their modulation for the potential treatment of serious human diseases like multiple myeloma, hepatocellular carcinoma, colorectal cancer, gastric cancer, ovarian cancer and glioblastoma. The role of miR regulation in the putative anti-diabetic effects of BBR is discussed, as well.

Peroxisome proliferator-activated receptor-γ enhances human pulmonary artery smooth muscle cell apoptosis through microRNA-21 and programmed cell death 4

Pulmonary hypertension (PH) is a progressive disorder whose cellular pathogenesis involves enhanced smooth muscle cell (SMC) proliferation and resistance to apoptosis signals. Existing evidence demonstrates that the tumor suppressor programmed cell death 4 (PDCD4) affects patterns of cell growth and repair responses in the systemic vasculature following experimental injury. In the current study, the regulation PDCD4 and its functional effects on growth and apoptosis susceptibility in pulmonary artery smooth muscle cells were explored. We previously demonstrated that pharmacological activation of the nuclear transcription factor peroxisome proliferator-activated receptor-γ (PPARγ) attenuated hypoxia-induced proliferation of human pulmonary artery smooth muscle cells (HPASMCs) by inhibiting the expression and mitogenic functions of microRNA-21 (miR-21). In the current study, we hypothesize that PPARγ stimulates PDCD4 expression and HPASMC apoptosis by inhibiting miR-21. Our findings demonstrate that PDCD4 is reduced in the mouse lung upon exposure to chronic hypoxia (10% O₂ for 3 wk) and in hypoxia-exposed HPASMCs (1% O₂). HPASMC apoptosis was reduced by hypoxia, by miR-21 overexpression, or by siRNA-mediated PPARγ and PDCD4 depletion. Activation of PPARγ inhibited miR-21 expression and resultant proliferation, while restoring PDCD4 levels and apoptosis to baseline. Additionally, pharmacological activation of PPARγ with rosiglitazone enhanced PDCD4 protein expression and apoptosis in a dose-dependent manner as demonstrated by increased annexin V detection by flow cytometry. Collectively, these findings demonstrate that PPARγ confers growth-inhibitory signals in hypoxia-exposed HPASMCs through suppression of miR-21 and the accompanying derepression of PDCD4 that augments HPASMC susceptibility to undergo apoptosis.

Synergetic Neuroprotective Effect of Docosahexaenoic Acid and Aspirin in SH-Y5Y by Inhibiting miR-21 and Activating RXRα and PPARα

Parkinson's disease (PD) is a serious neurodegenerative disorder that lacks effective therapeutic methods. In this research, expressions of PPARα, RXRα, and miR-21 were evaluated in PD patients and normal controls. To investigate the effects of miR-21, docosahexaenoic acid (DHA) and aspirin (ASA) on PD, as well as the relationships between them, SH-Y5Y cells were treated with DHA, ASA, or both for 24 h. The assay showed that levels of miR-21 were increased and levels of PPARα were decreased in PD patients compared with normal controls. miR-21 was negatively correlated with PPARα in PD patients. DHA and ASA could activate RXRα and PPARα, respectively. Additionally, DHA upregulated PPARα expression by inhibiting miR-21 in SH-Y5Y cells. A combination of DHA and ASA efficiently enhanced heterodimer formations of PPARα and RXRα and increased the expression of neurotrophic factors PSD-95, brain-derived neurotrophic factor (BDNF), and glial cell-derived neurotrophic factor (GDNF), while inhibiting NFκB and COX2. These findings suggest that a combination of DHA and ASA could significantly improve the expression of PSD-95, BDNF, and GDNF by promoting heterodimerization of PPARα and RXRα, thus supplying a new therapeutic method for PD.

Downregulation of Microrna-126 Contributes to Tumorigenesis of Squamous Tongue Cell Carcinoma via Targeting KRAS

BACKGROUND miR-126 has been reported to be differentially expressed in various malignancies, whereas its role in the pathogenesis of tongue squamous cell carcinoma (TSCC) remains largely unknown. MATERIAL AND METHODS In this study, we collected 21 pairs of TSCC cancerous and adjacent non-cancerous tissue samples, with which we performed real-time PCR to determine and compare the expression of 6 candidate miRNAs that are reportedly associated with tumorigenesis of TSCC, including miR-100, miR-451, miR-221, let-7a, miR-21, and miR-126. We further performed luciferase assay to validate KRAS as a target of miR-126, and conducted transfection to study the effect of miR-126 on proliferation and apoptosis of the cells. RESULTS We identified that miR-126 was significantly downregulated in the cancerous tissue samples compared with the non-cancerous control tissue samples. By using computational analysis, we identified that KRAS is a virtual target of miR-126, and such association was verified by using luciferase assay. In addition, we found that mRNA and protein expression level of KRAS was significantly higher in the tumor tissue than the control tissue samples. CONCLUSIONS The following in vitro experiment showed that both mRNA and protein KRAS expression were significantly decreased in SCC-15 cells in which miR-126 was overexpressed, in comparison with similar cells transfected with a negative control, while downregulation of miR-126 by transfecting the cells with miR-126 inhibitors significantly upregulated the mRNA and protein expression of KRAS.

CONCLUSIONS

miR-126 might be a promising diagnostic and therapeutic target in the prevention and management of TSCC patients.