MicroRNAs play a central role in molecular dysfunctions linking inflammation with cancer

The dual functional role of MicroRNA-18a (miR-18a) in cancer development

The polycistronic miR-17-92 cluster is instrumental in physiological processes commonly dysregulated in cancer, such as proliferation, the cell cycle, apoptosis, and differentiation. MicroRNA-18a (miR-18a) is one of the most conserved and multifunctional miRNAs in the cluster and is frequently overexpressed in malignant tumors. Altered miR-18a expression has been found in various physiological and pathological processes, including cell proliferation, apoptosis, epithelial-mesenchymal transition (EMT), tumorigenesis, cancer invasion and metastasis. In this review, we summarized the molecular basis and regulatory targets of miR-18a in cancer development. Interestingly, miR-18a has a dual functional role in either promoting or inhibiting oncogenesis in different human cancers. The differential miRNA expression in cancers of the same organ at different stages or of various subtypes suggests that this dual function of miR-18a is independent of cancer type and may be attributed to the fundamental differences in tumorigenic mechanisms. Finally, we summarized the current clinical use of miR-18a and discussed its potential uses in cancer therapy.

MicroRNA-155 and microRNA-181a, via HO-1, participate in regulating the immunotoxicity of cadmium in the kidneys of exposed Cyprinus carpio

Cadmium (Cd) is a nonessential metal that is a contaminant in aquatic ecosystems. Cd can accumulate in aquatic animals, leading to detrimental effects in tissues, and Cd exposure can induce immunotoxicity in fish. MicroRNAs (miRNAs) play critical roles in immune responses, yet the participation of miRNAs in Cd-induced immunotoxicity remains poorly understood. The present study evaluated the effects of Cd exposure on the immune responses and the mRNAs and miRNAs expressions of immune-related genes in Cyprinus carpio (C. carpio). Then, microRNA-155 (miR-155) was overexpressed and microRNA-181a (miR-181a) was knocked down to determine which miRNA plays a key role in the immune response to Cd. The results showed that 0.5 mg/L Cd²⁺ significantly decreased the activity of alkaline phosphatase (AKP) and acid phosphatase (ACP) in the kidneys of C. carpio. Cd exposure upregulated the mRNA expressions of interleukin (IL)-1β, IL-8, nuclear factor-kappa B (NF-κB), tumour necrosis factor-α (TNF-α), and Toll-like receptor 4(TLR-4) and downregulated those of IL-10 and heme oxygenase-1 (HO-1) in C. carpio kidneys. Cd exposure also led to upregulation of miR-155 and miR-181a expressions. Furthermore, AKP and ACP activity in the kidneys was markedly changed after intraperitoneal injection of C. carpio with miR-155 agomir and miR-181a antagomir. All detected mRNA expressions were significantly decreased after injection of miR-155 agomir, and IL-10, NF-κB, TNF-α, and HO-1 mRNA expressions were markedly increased after injection of miR-181a antagomir. The results of this study demonstrate that Cd exposure can immunocompromise C. carpio by targeting HO-1 through miR-155 and miR-181a. This is the first study to reveal that Cd exposure induces immunotoxicity through miR-155 and miR-181a in the kidneys of C. carpio.

A High-Content Screening Approach to Identify MicroRNAs Against Head and Neck Cancer Cell Survival and EMT in an Inflammatory Microenvironment

Head and neck squamous cell carcinoma (HNSCC) is among the most common cancer types. Metastasis, the main cause of death by cancer, can be promoted by an inflammatory microenvironment, which induces epithelial-mesenchymal transition (EMT) through a NF-κB-mediated stabilization of Snail. Here, we aimed to explore how microRNAs (miRs) can affect cell survival and EMT in HNSCC cells under an inflammatory microenvironment. By using a high-content screening (HCS) approach, we evaluated alterations in morphometric parameters, as well as expression/localization of Snail/Slug, in HNSCC cells primed with TNF-α. Based on those quantitation, we established the optimal experimental conditions of EMT induction driven by TNF-α. Those conditions were applied to cells transfected with distinct miRs (N = 31), followed by clusterization of miRs based on alterations related to cell survival and EMT. The signaling pathways enriched with molecular targets from each group of miRs were identified by in silico analyses. Finally, cells were transfected with siRNAs against signaling pathways targeted by miRs with anti-survival/EMT effect and evaluated for alterations in cell survival and EMT. Overall, we observed that TNF-α, at 20 ng/ml, induced EMT-related changes in cell morphology, Snail/Slug expression, and cell migration. Predicted targets of miRs with anti-survival/EMT effect were enriched with targets of NF-κB, PI3K/ATK, and Wnt/beta catenin pathways. Strikingly, individual gene silencing of elements from those pathways, namely RELA (NF-kB), AKT1 (PI3K/AKT), and CTNNB1 (Wnt/beta catenin) reduced cell survival and/or expression of Snail/Slug in cells stimulated with TNF-α. As a whole, our HCS approach allowed for the identification of miRs capable of inhibiting cell survival and EMT considering the presence of an inflammatory microenvironment, also indicating the common signaling pathways and molecular targets most likely to underlie those alterations. These findings may contribute to the development of targeted therapies against HNSCC.

Marek's Disease Virus-Encoded MicroRNA 155 Ortholog Critical for the Induction of Lymphomas Is Not Essential for the Proliferation of Transformed Cell Lines

Marek’s disease virus (MDV) is an alphaherpesvirus associated with Marek’s disease (MD), a highly contagious neoplastic disease of chickens. MD serves as an excellent model for studying virus-induced T-cell lymphomas in the natural chicken hosts. Among the limited set of genes associated with MD oncogenicity, MDV-miR-M4, a highly expressed viral ortholog of the oncogenic miR-155, has received extensive attention due to its direct role in the induction of lymphomas. Using a targeted CRISPR-Cas9-based gene editing approach in MDV-transformed lymphoblastoid cell lines, we show that MDV-miR-M4, despite its critical role in the induction of tumors, is not essential for maintaining the transformed phenotype and continuous proliferation. As far as we know, this was the first study in which precise editing of an oncogenic miRNA was carried out in situ in MD lymphoma-derived cell lines to demonstrate that it is not essential in maintaining the transformed phenotype.

MicroRNAs (miRNAs) are small noncoding RNAs with profound regulatory roles in many areas of biology, including cancer. MicroRNA 155 (miR-155), one of the extensively studied multifunctional miRNAs, is important in several human malignancies such as diffuse large B cell lymphoma and chronic lymphocytic leukemia. Moreover, miR-155 orthologs KSHV-miR-K12-11 and MDV-miR-M4, encoded by Kaposi’s sarcoma-associated herpesvirus (KSHV) and Marek’s disease virus (MDV), respectively, are also involved in oncogenesis. In MDV-induced T-cell lymphomas and in lymphoblastoid cell lines derived from them, MDV-miR-M4 is highly expressed. Using excellent disease models of infection in natural avian hosts, we showed previously that MDV-miR-M4 is critical for the induction of T-cell lymphomas as mutant viruses with precise deletions were significantly compromised in their oncogenicity. However, those studies did not elucidate whether continued expression of MDV-miR-M4 is essential for maintaining the transformed phenotype of tumor cells. Here using an in situ CRISPR/Cas9 editing approach, we deleted MDV-miR-M4 from the MDV-induced lymphoma-derived lymphoblastoid cell line MDCC-HP8. Precise deletion of MDV-miR-M4 was confirmed by PCR, sequencing, quantitative reverse transcription-PCR (qRT-PCR), and functional analysis. Continued proliferation of the MDV-miR-M4-deleted cell lines demonstrated that MDV-miR-M4 expression is not essential for maintaining the transformed phenotype, despite its initial critical role in the induction of lymphomas. Ability to examine the direct role of oncogenic miRNAs in situ in tumor cell lines is valuable in delineating distinct determinants and pathways associated with the induction or maintenance of transformation in cancer cells and will also contribute significantly to gaining further insights into the biology of oncogenic herpesviruses.

IMPORTANCE Marek’s disease virus (MDV) is an alphaherpesvirus associated with Marek’s disease (MD), a highly contagious neoplastic disease of chickens. MD serves as an excellent model for studying virus-induced T-cell lymphomas in the natural chicken hosts. Among the limited set of genes associated with MD oncogenicity, MDV-miR-M4, a highly expressed viral ortholog of the oncogenic miR-155, has received extensive attention due to its direct role in the induction of lymphomas. Using a targeted CRISPR-Cas9-based gene editing approach in MDV-transformed lymphoblastoid cell lines, we show that MDV-miR-M4, despite its critical role in the induction of tumors, is not essential for maintaining the transformed phenotype and continuous proliferation. As far as we know, this was the first study in which precise editing of an oncogenic miRNA was carried out in situ in MD lymphoma-derived cell lines to demonstrate that it is not essential in maintaining the transformed phenotype.

Biliary reflux as a causal factor in hypopharyngeal carcinoma: New clinical evidence and implications

BACKGROUND

Recent preclinical explorations strongly support the tumorigenic potential of bile on laryngopharyngeal mucosa. Herein, the authors describe, in bile-related human hypopharyngeal squamous cell carcinoma (HSCC), NF-κB-related messenger RNA (mRNA) and microRNA (miRNA) oncogenic phenotypes similar to those previously identified in acidic bile-exposed premalignant murine hypopharyngeal mucosa.

METHODS

In this pilot study, the authors included human HSCC specimens paired with their adjacent normal tissue (ANT) derived from 3 representative patients with documented biliary laryngopharyngeal reflux (bile[+]) compared with 5 control patients without signs of bile reflux disease (bile[-]). Immunohistochemical, quantitative polymerase chain reaction, and miRNA analyses were used to detect the levels of activated NF-κB and expression levels of STAT3, EGFR, BCL2, WNT5A, IL-6, IL-1B, ΔNp63, cREL, TNF-α, TP53, NOTCH1, NOTCH2, NOTCH3, miR-21, miR-155, miR-192, miR-34a, miR-375, miR-451a, miR-489, miR-504, and miR-99a.

RESULTS

Bile(+) HSCC demonstrated an intense NF-κB activation accompanied by significant overexpression of RELA(p65), EGFR, STAT3, BCL-2, cREL, ΔNp63, WNT5A, IL-6, and IL1B; upregulation of oncomir miR-21; and downregulation of tumor suppressor miR-375 compared with their respective ANTs. Bile(+) HSCC demonstrated significantly higher mRNA levels of all the analyzed genes, particularly RELA(p65), IL-6, EGFR, and TNF-α compared with bile(-) tumors. The miR-21/miR-375 ratio, which previously has been linked to tumor aggressiveness, was found to be >260-fold and >30-fold higher, respectively, in bile(+) HSCCs compared with their ANTs and bile(-) tumors.

CONCLUSIONS

Although limitations apply to this pilot study due to the small number of patients with HSCC, the novel findings suggest that a history of bile as a component of esophageal reflux disease may represent an independent risk factor for hypopharyngeal carcinogenesis.

Deregulation of miRNA in Helicobacter pylori-Induced Gastric MALT Lymphoma: From Mice to Human

Gastric MALT lymphoma (GML) is directly caused by Helicobacter pylori infection but occurs only in a small number of infected subjects. Mechanisms underlying the initiation and progression of GML remain unclear. MicroRNAs (miRNAs) are small non-coding RNAs that are now considered as major players in inflammation and carcinogenesis, acting as oncogenes or tumor suppressors. Previous laboratory studies have shown in a GML mouse model that overexpression of a distinct set of five miRNAs (miR-21a, miR-135b, miR-142a, miR-150, miR-155) could play a critical role in the pathogenesis of GML. Our goal was to compare the miRNA expression profile obtained in the GML mouse model to that in human GML (11 cases of GML compared to 17 cases of gastritis control population). RTqPCR on the five dysregulated miRNAs in the GML mouse model and PCR array followed by RTqPCR confirmation showed that four miRNAs were up-regulated (miR-150, miR-155, miR-196a, miR-138) and two miRNAs down-regulated (miR-153, miR-7) in the stomachs of GML patients vs. gastritis control population. The analysis of their validated targets allowed us to postulate that these miRNAs (except miR-138) could act synergistically in a common signaling cascade promoting lymphomagenesis and could be involved in the pathogenesis of GML.

miR-10b promoted melanoma progression through Wnt/β-catenin pathway by repressing ITCH expression

Dysregulation of microRNAs (miRNAs) have been reported to contribute to malignant progression in melanoma. However, the roles and mechanisms of several miRNAs in melanoma remain poorly understood. In our study, we showed that miR-10b was significantly up-regulated in melanoma tissues and cell lines, and was associated with overall survival of melanoma patients. Inhibition of miR-10b dramatically suppressed melanoma cell proliferation, migration and invasion in vitro and inhibited tumor growth in vivo. Moreover, we defined ITCH as a direct and functional downstream target of miR-10b, and showed that there was an inverse correlation between the expression of ITCH and miR-10b on melanoma tissues. Down-regulation of ITCH partially attenuated the inhibitory effects of miR-10b inhibition on melanoma cell proliferation, migration and invasion. Furthermore，we found that miR-10b exerted its effects on melanoma by regulating the Wnt/β-catenin pathway. Taken together, our results demonstrated that miR-10b was an important epigenetic modifier, promoting melanoma progression through regulating ITCH/Wnt/β-catenin pathway. These results offer a new strategy for epigenetic cancer therapy.

miR-155 expression in antitumor immunity: The higher the better?

MicroRNAs are small noncoding RNAs that modulate gene expression either directly, by impairing the stability and/or translation of transcripts that contain their specific target sequence, or indirectly through the targeting of transcripts that encode transcription factors, factors implicated in signal transduction pathways, or epigenetic regulators. Abnormal expression of micro-RNAs has been found in nearly all types of pathologies, including cancers. MiR-155 has been the first microRNA to be implicated in the regulation of the innate and adaptative immune responses, and its expression is either increased or decreased in a variety of liquid and solid malignancies. In this review, we examine the oncogenic and antitumor potentials of miR-155, with special emphasize on its dose-dependent effects. We describe the impact of miR-155 levels on antitumor activity of lymphocytes and myeloid cells. We discuss miR-155 dose-dependent effects in leukemias and analyze results showing that miR-155 intermediate levels tend to be detrimental, whereas high levels of miR-155 expression usually prove beneficial. We also examine the beneficial effects of high levels of miR-155 expression in solid tumors. We discuss the possible causal involvement of miR-155 in leukemias and dementia in individuals with Down's syndrome. We finally propose that increasing miR-155 levels in immune cells might increase the efficiency of newly developed cancer immunotherapies, due to miR-155 ability to target transcripts encoding immune checkpoints such as cytotoxic T lymphocyte antigen-4 or programmed death-ligand 1.

MiR-125b regulates the proliferation and metastasis of triple negative breast cancer cells via the Wnt/β-catenin pathway and EMT

BACKGROUND/AIM

MiR-125b plays an important role in breast cancer. The current study was to explore the expression and function of miR-125b in triple negative breast cancer cells.

MATERIALS AND METHODS

The expression of miR-125b in human TNBC samples and cell lines were examined by qRT-PCR. MTT, scratch assays and transwell assays were utilized to observe the proliferation, migration and invasion ability. MiR-125b's target gene and downstream signaling pathways were investigated by Luciferase Reporter Assays, qRT-PCR, immunofluorescence assays and western bolt.

RESULTS

MiR-125b was highly expressed in human TNBC tissues and cell lines. Inhibiting miR-125b expression suppressed the proliferation, cell migration and invasion. The three-prime untranslated region (3´-UTR) of adenomatous polyposis coli (APC) mRNA contains miR-125b binding sites, and inhibiting miR-125b expression suppressed the activity of the intracellular Wnt/β-catenin pathways and EMT.

CONCLUSION

Inhibiting miR-125b regulates the Wnt/β-catenin pathway and EMT to suppress the proliferation and migration of MDA-MB-468 TNBC cells.

Role of miR-155 in immune regulation and its relevance in oral lichen planus

Oral lichen planus (OLP) is a chronic mucosal inflammatory disease. The World Health Organization has described it as a potentially malignant condition. The pathogenesis of OLP remains to be fully elucidated, but extensive evidence suggests that immunologic and inflammatory factors have important roles. MicroRNAs (miRs), which are small non-coding RNAs, have been reported to be involved in OLP. In particular, miR-155 is significantly upregulated in patients with OLP. miR-155 has numerous functions and is closely linked to inflammation and immune system regulation. However, in-depth studies of the mechanisms via which miR-155 is involved in OLP are currently insufficient. Considering the close association between miR-155 and immune regulation as well as the importance of immune factors in OLP, the role of miR-155 in the immune system was herein summarized with a focus on OLP. The present review provides a basis for further study of the molecular mechanisms underlying the development and progression of OLP.

MicroRNA Expression in Focal Nodular Hyperplasia in Comparison with Cirrhosis and Hepatocellular Carcinoma

The liver disease focal nodular hyperplasia (FNH) has several histological features that resemble hepatic cirrhosis. Since cirrhosis may develop further into hepatocellular carcinoma (HCC) contrary to FNH, the aim of the present study was to identify microRNAs (miRNA), which, by their altered expression levels, may be associated with the benign, tumor-like nature of FNH. Altogether 106 surgically removed formalin-fixed paraffin-embedded liver samples were selected, including 22 FNH, 45 cirrhosis, 24 HCC and 15 normal liver tissues. Etiology of the cases of cirrhosis and HCC includes hepatitis C and alcoholism and the HCC cases developed in cirrhotic livers. Relative expression levels of 14 miRNAs were determined using TaqMan MicroRNA Assays. In comparison to normal liver, the levels of miR-34a and miR-224 were elevated not only in FNH but also in cirrhosis and HCC, while the expression of miR-17-5p, miR-18a and miR-210 was decreased in FNH. Further, the levels of miR-21 and miR-222 were increased in cirrhosis and HCC but were decreased in FNH and the expression of miR-17-5p, miR-18a, miR-195 and miR-210 was decreased in FNH as compared with cirrhosis and/or HCC. In conclusion, the elevation of miR-34a and miR-224 may be associated with both benign and malignant proliferative processes, nevertheless the increased expression of oncomiRs miR-21 and miR-222 in cirrhosis and HCC but not in FNH may be related to malignant processes of the liver. The decreased levels of miR-18a, miR-195 and miR-210 may further differentiate FNH from cirrhosis, reflecting the different pathogenesis of these two entities contrary to some histologically similar features.

MiR-155 deletion reduces ischemia-induced paralysis in an aortic aneurysm repair mouse model: Utility of immunohistochemistry and histopathology in understanding etiology of spinal cord paralysis

Spinal cord paralysis is relatively common after surgical repair of thoraco-abdominal aortic aneurysm (TAAA) and its etiology is unknown. The present study was designed to examine the histopathology of the disease and investigate whether miR-155 ablation would reduce spinal cord ischemic damage and delayed hindlimb paralysis induced by aortic cross-clamping (ACC) in our mouse model. The loss of locomotor function in ACC-paralyzed mice correlated with the presence of extensive gray matter damage and central cord edema, with minimal white matter histopathology. qRTPCR and Western blotting showed that the spinal cords of wild-type ACC mice that escaped paralysis showed lower miR-155 expression and higher levels of transcripts encoding Mfsd2a, which is implicated in the maintenance of blood-brain barrier integrity. In situ based testing demonstrated that increased miR-155 detection in neurons was highly correlated with the gray matter damage and the loss of one of its targets, Mfsd2a, could serve as a good biomarker of the endothelial cell damage. In vitro, we demonstrated that miR-155 targeted Mfsd2a in endothelial cells and motoneurons and increased endothelial cell permeability. Finally, miR-155 ablation slowed the progression of central cord edema, and reduced the incidence of paralysis by 40%. In sum, the surgical pathology findings clearly indicated that the epicenter of the ischemic-induced paralysis was the gray matter and that endothelial cell damage correlated to Mfsd2a loss is a good biomarker of the disease. MiR-155 targeting therefore offers new therapeutic opportunity for edema caused by traumatic spinal cord injury and diagnostic pathologists, by using immunohistochemistry, can clarify if this mechanism also is important in other ischemic diseases of the CNS, including stroke.

Noncoding RNA in NK cells

Noncoding RNAs (ncRNA) are important regulators that modulate cell proliferation, apoptosis, the cell cycle, and DNA methylation. NK cells mediate the immune response via the secretion of various cytokines and are important innate immune cells in the human immune system. Recent studies have found that ncRNA plays an important role in NK cell development and function. With recent advances in bioinformatics and next-generation sequencing, novel ncRNAs have been identified, allowing us to more fully appreciate its functions in NK cell biology. In this review, we summarize and discuss the latest studies on the functions and regulatory mechanisms of long noncoding RNA (lncRNA) and microRNA in NK cells from the viewpoint of epigenetic mechanisms to help us clearly understand ncRNA in NK cells.

Association between inflammatory potential of diet and risk of lung cancer among smokers in a prospective study in Singapore

BACKGROUND

Diet and inflammation have been suggested to be important risk factors for lung cancer. We examined the ability of the dietary inflammatory index (DII^®) to predict lung cancer in the Singapore Chinese Health Study (SCHS). The DII is a diet quality index based on the literature linking foods and nutrients with inflammatory biomarkers.

PATIENTS AND METHODS

Using data from the SCHS for 60,232 participants, including 1851 lung cancer cases, we investigated the associations of baseline DII scores calculated from a food frequency questionnaire with risk of developing lung cancer over an average of 17.6 years of follow-up. Hazard ratios (HR) were estimated using Cox regression, adjusting for smoking status and other risk factors.

RESULTS

After excluding cancers diagnosed in the first 2 years of follow-up, the DII was non-significantly associated with risk of lung cancer (HR_Q5vsQ1 = 1.13; 95% CI 0.94-1.35; P-trend = 0.24) after adjusting for age, dialect group, sex, interview year, education, body mass index, total calorie intake, physical activity and various smoking variables. In stratified analysis, stronger, statistically significant associations were evident in current smokers (HR 1.44; 95% CI 1.11-1.86; P_trend = 0.03, P for interaction = 0.003) and in male ever-smokers (HR_Q5vsQ1 = 1.37; 95% CI 1.07-1.77; P-trend = 0.03).

CONCLUSION

A pro-inflammatory diet, as shown by higher DII scores, is associated with an elevated risk of lung cancer for subjects with a history of smoking. Public health measures should be adopted to promote consumption of a healthy, anti-inflammatory diet to reduce the risk of lung cancer, especially in current and former smokers.

MicroRNA-136 promotes lipopolysaccharide-induced ATDC5 cell injury and inflammatory cytokine expression by targeting myeloid cell leukemia 1

Osteoarthritis is the most frequent chronic bone and joint diseases in older populations all over the world. Lipopolysaccharide (LPS)-induced murine chondrogenic ATDC5 cell model has been widely used for testing new osteoarthritis therapeutic targets. This study aimed to explore the effects of microRNA-136 (miR-136) on LPS-induced ATDC5 cell injury and inflammatory cytokine expression, as well as underlying potential mechanism. We found that LPS remarkably inhibited ATDC5 cell viability, induced ATDC5 cell apoptosis, and upregulated the expression of inflammatory cytokines, including interleukin 1β (IL-1β), IL-6, IL-8, and tumor necrosis factor α (TNF-α; P < .01 or  < .001). Moreover, LPS obviously upregulated the expression of miR-136 in ATDC5 cells (P < .05). Overexpression of miR-136 markedly exacerbated the LPS-induced ATDC5 cell viability inhibition, cell apoptosis enhancement, and inflammatory cytokine expression (P < .05), and suppression of miR-136 had opposite effects (P < .05). Myeloid cell leukemia 1 (Mcl-1) was a direct target gene of miR-136, which participated in the effect of miR-136 on LPS-induced ATDC5 cell inflammatory injury. Overexpression of Mcl-1 alleviated the LPS-induced inactivation of Wnt/β-catenin and Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling pathways, while suppression of Mcl-1 had opposite effects. To conclude, this study verified that miR-136 promoted LPS-induced ATDC5 cell injury and inflammatory cytokine expression by targeting Mcl-1, and Mcl-1 was involved in the regulatory effects of LPS on Wnt/β-catenin and JAK/STAT signaling pathways in ATDC5 cells.

MiR-663, a MicroRNA Linked with Inflammation and Cancer That Is under the Influence of Resveratrol

Resveratrol (trans-3,5,4′-trihydroxystilbene, RSV) is a non-flavonoid dietary polyphenol with antioxidant, anti-inflammatory and anti-cancer properties that is primarily found in red berries. While RSV displays many beneficial effects in vitro, its actual effects in vivo or in animal models remain passionately debated. Recent publications suggest that RSV pleiotropic effects could arise from its capability to regulate the expression and activity of microRNAs, short regulators themselves capable of regulating up to several hundreds of target genes. In particular, RSV increases microRNA miR-663 expression in different human cell lines, suggesting that at least some of its multiple beneficial properties are through the modulation of expression of this microRNA. Indeed, the expression of microRNA miR-663 is reduced in certain cancers where miR-663 is considered to act as a tumor suppressor gene, as well as in other pathologies such as cardiovascular disorders. Target of miR-663 include genes involved in tumor initiation and/or progression as well as genes involved in pathologies associated with chronic inflammation. Here, we review the direct and indirect effects of RSV on the expression of miR-663 and its target transcripts, with emphasise on TGFβ1, and their expected health benefits, and argue that elucidating the molecular effects of different classes of natural compounds on the expression of microRNAs should help to identify new therapeutic targets and design new treatments.

NLRP3 inflammasome mediates chronic intermittent hypoxia-induced renal injury implication of the microRNA-155/FOXO3a signaling pathway

Chronic intermittent hypoxia (CIH), as the foremost pathophysiological change of obstructive sleep apnea (OSA), contributes to continued deterioration in renal function. Nucleotide-binding domain like receptor protein 3 (NLRP3) inflammasome is a multiprotein complex that triggers innate immune responses to infection and cell stress through activation of caspase-1 and maturation of inflammatory pro-interleukin-1β cytokine. Emerging evidence indicates that inhibition of the NLRP3 inflammasome ameliorates renal injury. Nevertheless, it is uncertain whether NLRP3 inflammasome participates in CIH-induced renal injury. The molecular mechanisms modulating NLRP3 inflammasome activation remain to be elucidated. Compared with wild-type mice, NLRP3 knockout mice dramatically protected them from kidney injury, as indicated by the restoration of creatinine levels, lessened histopathological alterations, and the suppression of macrophages infiltration stained with F4/80. NLRP3 deficiency notably reversed CIH-induced oxidative stress (malondialdehyde and superoxide dismutase), concomitantly with the abrogated apoptosis-related proteins and proinflammatory signaling pathway. Consistently, NLRP3-deficient tubular cells remarkably inhibited reactive oxygen species generation and NLRP3 inflammasome activation. Furthermore, our study revealed that microRNA-155 (miR-155) was augmented in the renal tissue and HK-2 cells exposed to CIH. In addition, we investigated the role of miR-155 in the regulation of NLRP3 inflammasome. Inhibition of miR-155 suppressed the CIH-induced NLRP3 inflammasome activation in renal tubular cells, whereas overexpression of miR-155 promoted oxidation and enhanced NLRP3 pathway. Collectively, we demonstrated that miR-155 might be a positive-regulator of NLRP3 pathway by inhibiting the targeted FOXO3a gene. These results established a link between the miR-155/FOXO3a pathway and the NLRP3 inflammasome, suggesting pharmacological blockage of NLRP3 as a potential therapeutic strategy for OSA-associated chronic kidney disease.

MicroRNAs as Immunotherapy Targets for Treating Gastroenterological Cancers

Gastroenterological cancers are the most common cancers categorized by systems and are estimated to comprise 18.4% of all cancers in the United States in 2017. Gastroenterological cancers are estimated to contribute 26.2% of cancer-related death in 2017. Gastroenterological cancers are characterized by late diagnosis, metastasis, high recurrence, and being refractory to current therapies. Since the current targeted therapies provide limited benefit to the overall response and survival, there is an urgent need for developing novel therapeutic strategy to improve the outcome of gastroenterological cancers. Immunotherapy has been developed and underwent clinical trials, but displayed limited therapeutic benefit. Since aberrant expressions of miRNAs are found in gastroenterological cancers and miRNAs have been shown to regulate antitumor immunity, the combination therapy combining the traditional antibody-based immunotherapy and novel miRNA-based immunotherapy is promising for achieving clinical success. This review summarizes the current knowledge about the miRNAs and long noncoding RNAs that exhibit immunoregulatory roles in gastroenterological cancers and precancerous diseases of digestive system, as well as the miRNA-based clinical trials for gastroenterological cancers. This review also analyzes the ongoing challenge of identifying appropriate therapy candidates for complex and dynamic tumor microenvironment, ensuring efficient and targeted delivery to specific cancer tissues, and developing strategy for avoiding off-target effect.

Inter-Individual Variability in Acute Toxicity of R-Pulegone and R-Menthofuran in Human Liver Slices and Their Influence on miRNA Expression Changes in Comparison to Acetaminophen

Monoterpenes R-pulegone (PUL) and R-menthofuran (MF), abundant in the Lamiaceae family, are frequently used in herb and food products. Although their hepatotoxicity was shown in rodent species, information about their effects in human liver has been limited. The aim of our study was to test the effects of PUL, MF and acetaminophen (APAP, as a reference compound) on cell viability and microRNA (miRNA) expression in human precision-cut liver slices. Slices from five patients were used to follow up on the inter-individual variability. PUL was toxic in all liver samples (the half-maximal effective concentration was 4.0 µg/mg of tissue), while MF and surprisingly APAP only in two and three liver samples, respectively. PUL also changed miRNA expression more significantly than MF and APAP. The most pronounced effect was a marked decrease of miR-155-5p expression caused by PUL even in non-toxic concentrations in all five liver samples. Our results showed that PUL is much more toxic than MF and APAP in human liver and that miR-155-5p could be a good marker of PUL early hepatotoxicity. Marked inter-individual variabilities in all our results demonstrate the high probability of significant differences in the hepatotoxicity of tested compounds among people.

Lung adenocarcinoma cell-derived exosomal miR-21 facilitates osteoclastogenesis

Osteoclastogenesis is the rate-limiting step in tumor osteolytic metastasis. MicroRNAs play crucial roles in tumor progression and osteoclastogenesis regulation. Recent studies have demonstrated that exosomes are able to function as messengers that deliver microRNAs between cells. However, the effects of lung adenocarcinoma cell-derived exosomal miRNAs in osteoclastogenesis remain poorly understood. In this study, we found that exosomes derived from A549 cells facilitate osteoclastogenesis. As miR-21 was involved in tumorigenesis and osteoclastogenesis, we further proved the existence of miR-21 in A549 cell-derived exosomes and investigated its function. MiR-21 overexpression in A549 cells led to increased levels of miR-21 in exosomes and facilitated osteoclastogenesis. Conversely, miR-21 depletion in A549 cells down-regulated miR-21 in exosomes and alleviated osteoclastogenesis. Mechanical experiments demonstrated that exosomal miR-21 exerted its promoting effects on osteoclastogenesis via targeting Pdcd4, which is a known target of miR-21 and a regulator of osteoclastogenesis. Finally, clinical data showed that higher miR-21 levels were associated with a worse overall survival in lung adenocarcinoma patients. In conclusion, we found that lung adenocarcinoma derived exosomal miR-21 may facilitate osteoclastogenesis, which suggests that it is a potential therapeutic target of bone metastasis.

Human tRNA-Derived Small RNAs Modulate Host-Oral Microbial Interactions

Coevolution of the human host and its associated microbiota has led to sophisticated interactions to maintain a delicate homeostasis. Emerging evidence suggests that in addition to small molecules, peptides, and proteins, small regulatory noncoding RNAs (sRNAs) might play an important role in cross-domain interactions. In this study, we revealed the presence of diverse host transfer RNA-derived small RNAs (tsRNAs) among human salivary sRNAs. We selected 2 tsRNAs (tsRNA-000794 and tsRNA-020498) for further study based on their high sequence similarity to specific tRNAs from a group of Gram-negative oral bacteria, including Fusobacterium nucleatum, a key oral commensal and opportunistic pathogen. We showed that the presence of F. nucleatum triggers exosome-mediated release of tsRNA-000794 and tsRNA-020498 by human normal oral keratinocyte cells. Furthermore, both tsRNA candidates exerted a growth inhibition effect on F. nucleatum, likely through interference with bacterial protein biosynthesis, but did not affect the growth of Streptococcus mitis, a health-associated oral Gram-positive bacterium whose genome does not carry sequences bearing high similarity to either tsRNA. Our data provide the first line of evidence for the modulatory role of host-derived tsRNAs in the microbial-host interaction.

The Role of Activator Protein-1 (AP-1) Family Members in CD30-Positive Lymphomas

The Activator Protein-1 (AP-1) transcription factor (TF) family, composed of a variety of members including c-JUN, c-FOS and ATF, is involved in mediating many biological processes such as proliferation, differentiation and cell death. Since their discovery, the role of AP-1 TFs in cancer development has been extensively analysed. Multiple in vitro and in vivo studies have highlighted the complexity of these TFs, mainly due to their cell-type specific homo- or hetero-dimerization resulting in diverse transcriptional response profiles. However, as a result of the increasing knowledge of the role of AP-1 TFs in disease, these TFs are being recognized as promising therapeutic targets for various malignancies. In this review, we focus on the impact of deregulated expression of AP-1 TFs in CD30-positive lymphomas including Classical Hodgkin Lymphoma and Anaplastic Large Cell Lymphoma.

Toll-like 4 receptor /NFκB inflammatory/miR-146a pathway contributes to the ART-correlated preterm birth outcome

Assisted reproductive technology (ART) is widely used for the women with infertility conditions to achieve pregnancy. However, the adverse effects of ART may lead to poor perinatal and neonatal outcomes, e.g., preterm birth and low body weight. In this study, we investigated the inflammatory molecular factors and microRNA that might be involved in ART related preterm birth. We found the elevation of Toll-like 4 receptor (TLR4), activation of NFκB pathway and down-regulation of microRNA-146a (miR-146a), a negative regulator of NFκB, in the placenta of preterm birth and ART, indicating preterm birth and ART were associated with inflammation signaling activation. In vitro experiments demonstrated that miR-146a suppressed NFκB pathway and shifted the balance of cytokines in the cord blood toward a repertoire of pro-inflammatory outcomes by down-regulating IRAK1 and TRAF6. The pro-inflammatory cytokines IL-6, IFNγ and TNFα in the cord blood were highly expressed in the preterm and ART, while anti-inflammatory cytokine IL-10 was the lower in the preterm and ART. In summary, we firstly uncovered that TLR4/NFκB mediated inflammation signaling and miR-146a participated in ART-related preterm birth patients, which suggests that importance of TLR4/NFκB/miR-146a signaling in clinical interventions and biomarkers of ART-related perinatal or neonatal outcomes.

NF-κB inhibition reverses acidic bile-induced miR-21, miR-155, miR-192, miR-34a, miR-375 and miR-451a deregulations in human hypopharyngeal cells

We previously demonstrated that acidic bile activates NF-κB, deregulating the expression of oncogenic miRNA markers, in pre-malignant murine laryngopharyngeal mucosa. Here, we hypothesize that the in vitro exposure of human hypopharyngeal cells to acidic bile deregulates cancer-related miRNA markers that can be reversed by BAY 11-7082, a pharmacologic NF-κB inhibitor. We repetitively exposed normal human hypopharyngeal primary cells and human hypopharyngeal keratinocytes to bile fluid (400 μmol/L), at pH 4.0 and 7.0, with/without BAY 11-7082 (20 μmol/L). We centred our study on the transcriptional activation of oncogenic miR-21, miR-155, miR-192, miR-34a, miR-375, miR-451a and NF-κB-related genes, previously linked to acidic bile-induced pre-neoplastic events. Our novel findings in vitro are consistent with our hypothesis demonstrating that BAY 11-7082 significantly reverses the acidic bile-induced oncogenic miRNA phenotype, in normal hypopharyngeal cells. BAY 11-7082 strongly inhibits the acidic bile-induced up-regulation of miR-192 and down-regulation of miR-451a and significantly decreases the miR-21/375 ratios, previously related to poor prognosis in hypopharyngeal cancer. This is the first in vitro report that NF-κB inhibition reverses acidic bile-induced miR-21, miR-155, miR-192, miR-34a, miR-375 and miR-451a deregulations in normal human hypopharyngeal cells, suggesting that acidic bile-induced events are directly or indirectly dependent on NF-κB signalling.

MicroRNA implications in the etiopathogenesis of ankylosing spondylitis

Ankylosing spondylitis (AS) is a chronic immune-mediated inflammatory disease that affects both axial and peripheral skeletons as well as soft tissues. Recent investigations offer that disease pathogenesis is ascribed to a complex interplay of genetic, environmental, and immunological factors. Until now, there is no appropriate method for early diagnosis of AS and the successful available therapy for AS patients stay largely undefined. MicroRNAs (miRNAs), endogenous small noncoding RNAs controlling the functions of target mRNAs and cellular processes, are present in human plasma in a stable form and have appeared as possible biomarkers for activity, pathogenesis, and prognosis of the disease. In the present review, we have tried to summarize the recent findings related to miRNAs in AS development and discuss the possible utilization of these molecules as prognostic biomarkers or important therapeutic strategies for AS. Further examinations are needed to determine the unique miRNAs signatures in AS and characterize the mechanisms mediated by miRNAs in the pathology of this disease.

Correlation between serum IL-1β and miR-144-3p as well as their prognostic values in LUAD and LUSC patients

BACKGROUND

IL-1β is an essential factor of inflammation initiation, and it also promotes malignant transformation, indicating its tumorigenic property. We aimed to investigate the correlation between IL-1β and miR-144-3p as well as their prognostic values in LUAD and LUSC patients.

RESULTS

The IL-1β level in both LUAD and LUSC patients was significantly higher than that of healthy donors (P < 0.001). In both populations, patients with low IL-1β level had better prognosis than high IL-1β level (P < 0.001 and P = 0.010, respectively). In A549 cells, miR-144 showed the biggest expression change (-4.38 fold) after IL-1β exposure. In LUAD patients, a negative correlation was detected between IL-1β and miR-144-3p (r = -0.540, P < 0.001) and the high miR-144-3p group had better prognosis (P = 0.003), which was validated by TCGA data. Clinical stage, IL-1β and miR-144-3p were independent risk factors in LUAD patients. In vitro, IL-1β and miR-144-3p antagomir could enhance proliferation and miR-144-3p mimics would attenuate the promoting effect of IL-1β.

MATERIALS AND METHODS

ELISA and qRT-PCR were applied respectively to detected cytokines and miR-144-3p in 129 LUAD, 54 LUSC and 40 healthy donors. Moreover, miRNA array was carried out for miRNA profiling. TCGA database was employed for validation, and follow up data were collected for prognosis evaluation. MTT assay and western-blot were carried out for proliferation evaluation.

CONCLUSIONS

In LUAD patients, the serum IL-1β level was correlated with miR-144-3p may affect miR-144-3p at transcriptional level. Both of them were independent risk factors for LUAD prognosis. In addition, IL-1β and miR-144-3p might mediate inflammation-promoted tumorigenesis in LUAD patients.

Modulating inflammation through the negative regulation of NF-κB signaling

Immune system activation is essential to thwart the invasion of pathogens and respond appropriately to tissue damage. However, uncontrolled inflammation can result in extensive collateral damage underlying a diverse range of auto-inflammatory, hyper-inflammatory, and neoplastic diseases. The NF-κB signaling pathway lies at the heart of the immune system and functions as a master regulator of gene transcription. Thus, this signaling cascade is heavily targeted by mechanisms designed to attenuate overzealous inflammation and promote resolution. Mechanisms associated with the negative regulation of NF-κB signaling are currently under intense investigation and have yet to be fully elucidated. Here, we provide an overview of mechanisms that negatively regulate NF-κB signaling through either attenuation of signal transduction, inhibition of posttranscriptional signaling, or interference with posttranslational modifications of key pathway components. While the regulators discussed for each group are far from comprehensive, they exemplify common mechanistic approaches that inhibit this critical biochemical signaling cascade. Despite their diversity, a commonality among these regulators is their selection of specific targets at key inflection points in the pathway, such as TNF-receptor-associated factor family members or essential kinases. A better understanding of these negative regulatory mechanisms will be essential to gain greater insight related to the maintenance of immune system homeostasis and inflammation resolution. These processes are vital elements of disease pathology and have important implications for targeted therapeutic strategies.

MicroRNA-155-5p Overexpression in Peripheral Blood Mononuclear Cells of Chronic Lymphocytic Leukemia Patients Is a Novel, Independent Molecular Biomarker of Poor Prognosis

MicroRNA-155-5p (miR-155-5p) is a proinflammatory, oncogenic miRNA, involved in various physiological processes, including hematopoiesis, immunity, inflammation, and cell lineage differentiation. It regulates important transcription factors, such as E2F2, hypoxia-inducible factor 1 (HIF1), and FOXO3. Recently, the dysregulation of miR-155-5p expression has been linked to chronic lymphocytic leukemia (CLL) pathogenesis. In this research study, we investigated the potential diagnostic and prognostic value of miR-155-5p in CLL. To achieve our goal, we isolated total RNA from peripheral blood mononuclear cells (PBMCs) collected from 88 CLL patients and 36 nonleukemic blood donors and performed polyadenylation of total RNA and reverse transcription. Next, we quantified miR-155-5p levels using an in-house-developed real-time quantitative PCR method, before proceeding to extensive biostatistical analysis. Thus, it appears that miR-155-5p is significantly overexpressed in PBMCs of CLL patients and can distinguish them from nonleukemic population. Kaplan-Meier OS analysis and bootstrap univariate Cox regression showed that high miR-155-5p expression predicts inferior OS for CLL patients (p < 0.001). Interestingly, miR-155-5p overexpression retains its unfavorable prognostic role in CLL patients stratified according to established prognostic factors [CD38 expression and mutational status of the immunoglobulin heavy chain variable region (IGHV)]. Thus, miR-155-5p appears as a promising, independent molecular biomarker of unfavorable prognosis in CLL.

MicroRNAs in intestinal barrier function, inflammatory bowel disease and related cancers-their effects and therapeutic potentials

The initiation and development or inflammatory bowel disease (IBD) and associated colorectal cancers, have been linked to inflammation. MicroRNAs are non-coding regulators of gene expression that have gained great attention due to their capability to regulate the expression of a number of target transcripts. It is now generally admitted that microRNAs are instrumental in gut pathologies, in particular through their targeting of transcripts encoding proteins of the intestinal barrier (IB) and their regulators. Intense research is conducted to identify microRNAs susceptible to be used as biomarkers and to design new therapeutic approaches based upon using synthetic microRNA mimics and inhibitors as well as finding new drugs capable to restore or modify microRNA expression in the context of gut pathologies.

Global and targeted circulating microRNA profiling of colorectal adenoma and colorectal cancer

BACKGROUND

Circulating microRNAs (miRNAs) are emerging as promising biomarkers for cancer. The objective of the current study was to investigate the potential of circulating cell-free miRNAs as biomarkers for colorectal cancer (CRC) and its precursor lesion, colorectal adenoma.

METHODS

The serum levels of 800 miRNAs were assessed in a discovery set of 21 patients with CRC, 19 patients with adenoma, and 21 healthy controls using the NanoString miRNA analysis platform. Significantly differentially expressed miRNAs were examined further in a validation cohort of 34 patients with CRC, 33 patients with adenoma, and 35 healthy controls using Fluidigm quantitative polymerase chain reaction assays.

RESULTS

The ratios between the expression values of the differentially expressed miRNAs were computed. Three miRNA ratios (miR-17-5p/miR-135b, miR-92a-3p/miR135b, and miR-451a/miR-491-5p) were validated for discriminating patients with adenoma and those with CRC from the healthy control group, and 5 miRNA ratios (let-7b/miR-367-3p, miR-130a-3p/miR-409-3p, miR-148-3p/miR-27b, miR-148a-3p/miR-409-3p, and miR-21-5p/miR-367-3p) were validated for discriminating patients with CRC from those with adenoma and healthy controls. The area under the receiver operating characteristic curve values for the 3 miRNA ratios in discriminating patients with adenoma from healthy controls were 0.831 and 0.735, respectively, in the discovery and validation sets. The area under the receiver operating characteristic curve values for the 5 miRNA ratios in discriminating patients with CRC from those with adenoma were 0.797 and 0.732, respectively, in the discovery and validation sets. Pathway analysis revealed that target genes regulated by the miRNAs from the miRNA ratios were enriched mainly in metabolism-related and inflammation-related pathways.

CONCLUSIONS

The data from the current study suggest that circulating miRNAs can distinguish patients with CRC and those with adenoma and may represent novel biomarkers for the early, noninvasive detection of CRC. Cancer 2018;124:785-96. © 2017 American Cancer Society.

Immune Modulatory microRNAs Involved in Tumor Attack and Tumor Immune Escape

Current therapies against cancer utilize the patient's immune system for tumor eradication. However, tumor cells can evade immune surveillance of CD8+ T and/or natural killer (NK) cells by various strategies. These include the aberrant expression of human leukocyte antigen (HLA) class I antigens, co-inhibitory or costimulatory molecules, and components of the interferon (IFN) signal transduction pathway. In addition, alterations of the tumor microenvironment could interfere with efficient antitumor immune responses by downregulating or inhibiting the frequency and/or functional activity of immune effector cells and professional antigen-presenting cells. Recently, microRNAs (miRNAs) have been identified as major players in the post-transcriptional regulation of gene expression, thereby controlling many physiological and also pathophysiological processes including neoplastic transformation. Indeed, the cellular miRNA expression pattern is frequently altered in many tumors of distinct origin, demonstrating the tumor suppressive or oncogenic potential of miRNAs. Furthermore, there is increasing evidence that miRNAs could also influence antitumor immune responses by affecting the expression of immune modulatory molecules in tumor and immune cells. Apart from their important role in tumor immune escape and altered tumor-host interaction, immune modulatory miRNAs often exert neoplastic properties, thus representing promising targets for future combined immunotherapy approaches. This review focuses on the characterization of miRNAs involved in the regulation of immune surveillance or immune escape of tumors and their potential use as diagnostic and prognostic biomarkers or as therapeutic targets.

A Novel Pak1/ATF2/miR-132 Signaling Axis Is Involved in the Hematogenous Metastasis of Gastric Cancer Cells

We, along with others, have shown previously that P21-activated kinase 1 (Pak1) plays a pivotal role in gastric cancer progression and metastasis. However, whether Pak1 controls gastric cancer metastasis by regulating microRNAs (miRNAs) has never been explored. Here, we report a novel mechanism of Pak1 in tumor metastasis. A detailed examination revealed that Pak1 interacts with and phosphorylates the serine 62 residue of ATF2 and then blocks its translocation into the nucleus. We also confirmed that ATF2 binds to the promoter of miR-132 and tightly regulates its transcription, thus explaining the regulatory mechanism of miR-132 by Pak1. miR-132 also significantly reduced cell adhesion, migration, and invasion of gastric cancer cells in vitro and significantly prevented tumor metastasis in vivo. miR-132 specifically inhibited hematogenous metastasis, but not lymph node or implantation metastases. In order to further delineate the effects of the Pak1/ATF2/miR-132 cascade on gastric cancer progression, we identified several targets of miR-132 using a bioinformatics TargetScan algorithm. Notably, miR-132 reduced the expression of CD44 and fibronectin1 (FN1), and such inhibition enabled lymphocytes to home in on gastric cancer cells and induce tumor apoptosis. Taken together, our studies establish a novel cell-signaling pathway and open new possibilities for therapeutic intervention of gastric cancer.

Resveratrol as a Natural Autophagy Regulator for Prevention and Treatment of Alzheimer's Disease

Alzheimer’s disease (AD) is one of the most common neurodegenerative disorders over the age of 65 years old. Although several underlying mechanisms for explaining the pathogenesis of AD are elucidated, the effective supplements or drugs for the intervention of AD are still limited. Recently, impaired autophagy associated with miRNA dysfunction has been reported to involve in aging and aging-related neurodegenerative diseases. Thus, the activation of autophagy through effectively regulating miRNAs may become a potential target for the prevention or treatment of AD. Mounting evidence from in vitro and in vivo AD models has demonstrated that resveratrol, one of polyphenolic compounds, can exert neuroprotective role in neurodegenerative diseases especially AD. In this review, the regulation of miRNAs and autophagy using resveratrol during the prevention and treatment of AD are systematically discussed, which will be beneficial to establish a target for the direct link between pharmacological intervention and AD in the future.

MicroRNAs and Cancer: A Long Story for Short RNAs

More than six decades ago Watson and Crick published the chemical structure of DNA. This discovery revolutionized our approach to medical science and opened new perspectives for the diagnosis and treatment of many diseases including cancer. Since then, progress in molecular biology, together with the rapid advance of technologies, allowed to clone hundreds of protein-coding genes that were found mutated in all types of cancer. Normal and aberrant gene functions, interactions, and mechanisms of mutations were studied to identify the intricate network of pathways leading to cancer. With the acknowledgment of the genetic nature of cancer, new diagnostic, prognostic, and therapeutic strategies have been attempted and developed, but very few have found their way in the clinical field. In an effort to identify new translational targets, another great discovery has changed our way to look at genes and their functions. MicroRNAs have been the first noncoding genes involved in cancer. This review is a brief chronological history of microRNAs and cancer. Through the work of few of the greatest scientists of our times, this chapter describes the discovery of microRNAs from C. elegans to their debut in cancer and in the medical field, the concurrent development of technologies, and their future translational applications. The purpose was to share the exciting path that lead to one of the most important discoveries in cancer genetics in the past 20 years.

Mutation-promoting molecular networks of uncontrolled inflammation

More and more studies show that chronic inflammation can lead to tumor formation. The complex interactions of inflammatory cells, stroma and tumor parenchymal cell are closely related to tumor formation. Under the state of chronic inflammatory microenvironment, long-term interaction of inflammatory cells and stromal cells as well as the parenchymal cells makes signaling pathway in parenchyma cells disordered. A series of gene level editor modification, epigenetic changes, and the regulation of transcription and translation changes will happen based on signaling pathway disorder. The changes ultimately lead to cell mutations and phenotypic transformation occurred. Recent findings provide an objective basis for cancer treatment and prevention. However, further discusses at the core of the possible molecular in tumor formation provide a theoretical foundation for future study of the pathogenesis and molecular targeted therapy of cancer. This review summarizes the research in the field of chronic inflammation and cancer in recent years, and analyze the molecules network in the process of the carcinogenic inflammation comprehensively. Beyond that, this review intends to describe possible carcinogenic inflammation core molecular and provides a theoretical basis for future study of the pathogenesis, chemoprevention and molecular targeted therapy of cancer.

GAS5 suppresses malignancy of human glioma stem cells via a miR-196a-5p/FOXO1 feedback loop

Glioma stem cells (GSCs) make up highly tumorigenic subpopulations within gliomas, and aberrant expression of GSC genes is a major underlying cause of glioma pathogenesis and treatment failure. The present study characterized the expression and function of long non-coding RNA growth arrest specific 5 (GAS5) in GSCs in order to elucidate the molecular mechanisms by which GAS5 contributes to glioma pathogenesis. We demonstrate that GAS5 suppresses GSC malignancy by binding to miR-196a-5p. miR-196a-5p, an onco-miRNA, stimulates GSC proliferation, migration, and invasion, in addition to reducing levels of apoptosis. miR-196a-5p specifically downregulates the expression of forkhead box protein O1 (FOXO1) by targeting its 3' untranslated region (3'-UTR). FOXO1 upregulates expression of phosphotyrosine interaction domain containing 1 (PID1), thereby inhibiting GSC tumorigenicity and growth. FOXO1 also upregulates migration and invasion inhibitory protein (MIIP), resulting in attenuation of migration and invasion activities. Interestingly, we also show that FOXO1 promotes GAS5 transcription, thus forminga positive feedback loop. These data provide insights into potential new pathways for GSC molecular therapy and suggest that GAS5 may be an efficacious target for glioma treatments.

A Tiny RNA that Packs a Big Punch: The Critical Role of a Viral miR-155 Ortholog in Lymphomagenesis in Marek's Disease

MicroRNAs (miRNAs) are small non-coding RNAs that have been identified in animals, plants, and viruses. These small RNAs play important roles in post-transcriptional regulation of various cellular processes, including development, differentiation, and all aspects of cancer biology. Rapid-onset T-cell lymphoma of chickens, namely Marek’s disease (MD), induced by Gallid alphaherpesvirus 2 (GaHV2), could provide an ideal natural animal model for herpesvirus-related cancer research. GaHV2 encodes 26 mature miRNAs derived from 14 precursors assembled in three distinct gene clusters in the viral genome. One of the most highly expressed GaHV2 miRNAs, miR-M4-5p, shows high sequence similarity to the cellular miR-155 and the miR-K12-11 encoded by Kaposi’s sarcoma-associated herpesvirus, particularly in the miRNA “seed region.” As with miR-K12-11, miR-M4-5p shares a common set of host and viral target genes with miR-155, suggesting that they may target the same regulatory cellular networks; however, differences in regulatory function between miR-155 and miR-M4-5p may distinguish non-viral and viral mediated tumorigenesis. In this review, we focus on the functions of miR-M4-5p as the viral ortholog of miR-155 to explore how the virus mimics a host pathway to benefit the viral life cycle and trigger virus-induced tumorigenesis.

Identification of differentially expressed miRNAs associated with chronic kidney disease-mineral bone disorder

The purpose of this study is to characterize a meta-signature of differentially expressed mRNA in chronic kidney disease (CKD) to predict putative microRNA (miRNA) in CKD-mineral bone disorder (CKD-MBD) and confirm the changes in these genes and miRNA expression under uremic conditions by using a cell culture system. PubMed searches using MeSH terms and keywords related to CKD, uremia, and mRNA arrays were conducted. Through a computational analysis, a meta-signature that characterizes the significant intersection of differentially expressed mRNA and expected miRNAs associated with CKD-MBD was determined. Additionally, changes in gene and miRNA expressions under uremic conditions were confirmed with human Saos-2 osteoblast-like cells. A statistically significant mRNA meta-signature of upregulated and downregulated mRNA levels was identified. Furthermore, miRNA expression profiles were inferred, and computational analyses were performed with the imputed microRNA regulation based on weighted ranked expression and putative microRNA targets (IMRE) method to identify miRNAs associated with CKD occurrence. TLR4 and miR-146b levels were significantly associated with CKD-MBD. TLR4 levels were significantly downregulated, whereas primiR- 146b and miR-146b were upregulated in the presence of uremic toxins in human Saos-2 osteoblast-like cells. Differentially expressed miRNAs associated with CKD-MBD were identified through a computational analysis, and changes in gene and miRNA expressions were confirmed with an in vitro cell culture system.

Twist1/Dnmt3a and miR186 establish a regulatory circuit that controls inflammation-associated prostate cancer progression

Increasing evidences suggest that inflammatory microenvironment has a crucial role in prostate cancer (PCa) progression; however, the underlying mechanisms are unclear. Here, we used the inflammation-associated prostate cellular transformation model to screen out a crucial microRNA, miR186, which was significantly downregulated in the transformed cells and effectively rescued the transformed phenotype. On stimulation of inflammatory cytokines, the activated nuclear factor kappa B (NF-κB)/p65 was able to induce miR186 expression through binding to its promoter in non-transformed cells, whereas this pathway was lost in transformed cells. Interestingly, Twist1, which is a reported downstream target of miR186, was responsible for the loss of NF-κB/p65-miR186 pathway. Twist1 downregulated miR186 expression in a novel negative feedback loop binding to the E-box and simultaneously recruiting Dnmt3a, which facilitated the site-specific CpG methylation of the miR186 promoter, thereby blocked the transcriptional activity of NF-κB/p65 and the responsiveness of miR186 to inflammatory signals. The high level of Twist1 triggered this feedback loop that underlies the epigenetic switch, which was essential for maintaining transformed and advanced PCa state. Finally, our clinical data confirmed that the CpG methylation and miR186 expression levels were closely related with inflammation-associated human PCa progression.

Silencing NKG2D ligand-targeting miRNAs enhances natural killer cell-mediated cytotoxicity in breast cancer

NKG2D is one of the major activating receptors of natural killer (NK) cells and binds to several ligands (NKG2DLs). NKG2DLs are expressed on malignant cells and sensitize them to early elimination by cytotoxic lymphocytes. We investigated the clinical importance of NKG2DLs and the mechanism of NKG2DL regulation in breast cancer (BC). Among the NKG2DLs MICA/B and ULBP1/2/3, the expression levels of MICA/B in BC tissues were inversely associated with the Tumor Node Metastasis stage. We first found that the high expression of MICB, but not MICA, was an independent prognostic factor for overall survival in patients with BC. Investigation into the mechanism revealed that a group of microRNAs (miRNAs) belonging to the miR-17-92 cluster, especially miR-20a, decreased the expression of ULBP2 and MICA/B. These miRNAs downregulated the expression of MICA/B by targeting the MICA/B 3'-untranslated region and downregulated ULBP2 by inhibiting the MAPK/ERK signaling pathway. Functional analysis showed that the silencing of NKG2DL-targeting miRNAs in BC cells increased NK cell-mediated cytotoxicity in vitro and inhibited immune escape in vivo. In addition, histone deacetylase inhibitors (HDACis) increased NKG2DL expression in BC cells by inhibiting members of the miR-17-92 cluster. Thus, targeting miRNAs with antisense inhibitors or HDACis may represent a novel approach for increasing the immunogenicity of BC.

Tissue MicroRNA profiles as diagnostic and prognostic biomarkers in patients with resectable pancreatic ductal adenocarcinoma and periampullary cancers

Background

The aim of this study was to validate previously described diagnostic and prognostic microRNA expression profiles in tissue samples from patients with pancreatic cancer and other periampullary cancers.

Methods

Expression of 46 selected microRNAs was studied in formalin-fixed paraffin-embedded tissue from patients with resected pancreatic ductal adenocarcinoma (n = 165), ampullary cancer (n=59), duodenal cancer (n = 6), distal common bile duct cancer (n = 21), and gastric cancer (n = 20); chronic pancreatitis (n = 39); and normal pancreas (n = 35). The microRNAs were analyzed by PCR using the Fluidigm platform.

Results

Twenty-two microRNAs were significantly differently expressed in patients with pancreatic cancer when compared to healthy controls and chronic pancreatitis patients; 17 miRNAs were upregulated (miR-21-5p, −23a-3p, −31-5p, −34c-5p, −93-3p, −135b-3p, −155-5p, −186-5p, −196b-5p, −203, −205-5p, −210, −222-3p, −451, −492, −614, and miR-622) and 5 were downregulated (miR-122-5p, −130b-3p, −216b, −217, and miR-375). MicroRNAs were grouped into diagnostic indices of varying complexity. Ten microRNAs associated with prognosis were identified (let-7 g, miR-29a-5p, −34a-5p, −125a-3p, −146a-5p, −187, −205-5p, −212-3p, −222-5p, and miR-450b-5p). Prognostic indices based on differences in expression of 2 different microRNAs were constructed for pancreatic and ampullary cancer combined and separately (30, 5, and 21 indices).

Conclusion

The study confirms that pancreatic cancer tissue has a microRNA expression profile that is different from that of other periampullary cancers, chronic pancreatitis, and normal pancreas. We identified prognostic microRNAs and microRNA indices that were associated with shorter overall survival in patients with radically resected pancreatic cancer.

Electronic supplementary material

The online version of this article (doi:10.1186/s40364-017-0087-6) contains supplementary material, which is available to authorized users.

MicroRNA therapeutics: towards a new era for the management of cancer and other diseases

In just over two decades since the discovery of the first microRNA (miRNA), the field of miRNA biology has expanded considerably. Insights into the roles of miRNAs in development and disease, particularly in cancer, have made miRNAs attractive tools and targets for novel therapeutic approaches. Functional studies have confirmed that miRNA dysregulation is causal in many cases of cancer, with miRNAs acting as tumour suppressors or oncogenes (oncomiRs), and miRNA mimics and molecules targeted at miRNAs (antimiRs) have shown promise in preclinical development. Several miRNA-targeted therapeutics have reached clinical development, including a mimic of the tumour suppressor miRNA miR-34, which reached phase I clinical trials for treating cancer, and antimiRs targeted at miR-122, which reached phase II trials for treating hepatitis. In this article, we describe recent advances in our understanding of miRNAs in cancer and in other diseases and provide an overview of current miRNA therapeutics in the clinic. We also discuss the challenge of identifying the most efficacious therapeutic candidates and provide a perspective on achieving safe and targeted delivery of miRNA therapeutics.

MicroRNA-155 promotes the pathogenesis of experimental colitis by repressing SHIP-1 expression

AIM

To explore the mechanism by which microRNA-155 (miR-155) regulates the pathogenesis of experimental colitis.

METHODS

A luciferase assay was performed to confirm the binding of miR-155 to the SHIP-1 3’-UTR. MiR-155 mimics, negative controls and SHIP-1 expression/knockdown vectors were established and then utilized in gain- and loss-of-function studies performed in raw264.7 cells and primary bone marrow-derived macrophages (BMDMs). Thereafter, dextran sulfate sodium (DSS)-induced colitis mouse model with or without antagomiR-155 treatment was established, and the levels of miR-155 and SHIP-1, as well as the pro-inflammatory capabilities, were measured by western blot, quantitative polymerase chain reaction, and immunohistochemistry.

RESULTS

MiR-155 directly bound to the 3’-UTR of SHIP-1 mRNA and induced a significant decrease in SHIP-1 expression in both raw264.7 cells and primary BMDMs. MiR-155 markedly promoted cell proliferation and pro-inflammatory secretions including IL-6, TNF-α, IL-1β, and IFN-γ, whereas these effects could be reversed by the restoration of SHIP-1 expression. In vivo studies showed that antagomiR-155 administration could alleviate DSS-induced intestinal inflammation in Balb/c mice. Moreover, significantly increased SHIP-1 expression, as well as decreased Akt activation and inflammatory response, were observed in the antagomiR-155-treated mice.

CONCLUSION

MiR-155 promotes experimental colitis by repressing SHIP-1 expression. Thus, the inhibition of miR-155 might be a promising strategy for therapy.

miR-125b Enhances IL-8 Production in Early-Onset Severe Preeclampsia by Targeting Sphingosine-1-Phosphate Lyase 1

Preeclampsia (PE) is one of the leading causes of maternal and perinatal mortality and morbidity. One of the main hallmarks observed in PE is impaired inflammation state. In the current study, we found that miR-125b was deregulated in placental tissues and plasma derived from PE patients, which suggest a potential association between this miRNA and the pathogenesis of PE. Overexpression of miR-125b significantly reduced SGPL1 expression, and luciferase assays confirmed that SGPL1 is a direct target of miR-125b. We also found that miR-125b enhanced IL-8 production by directly targeting sphingosine-1-phosphate lyase 1 (SGPL1), and this effect could be reversed by SGPL1 overexpression. In placentas derived from PE patients, a negative correlation of miR-125b and SGPL1 was observed, and IL-8 was validated to be increased in the circulation of PE patients. Our data demonstrated a critical role of miR-125b in IL-8 production and the development of PE.