miR-137 targets Cdc42 expression, induces cell cycle G1 arrest and inhibits invasion in colorectal cancer cells

Epigenetic Suppression of miR-137 Induces RNF4 Expression, Facilitating Wnt Signaling in Colorectal Cancer

Colorectal cancer (CRC) is a significant health issue worldwide. Recent studies highlight the critical role of miRNAs in CRC development, particularly miR-137, which acts as a key tumor suppressor. Despite its known role, further exploration of miR-137's downstream signaling is needed to understand its biology and therapeutic potential. We examined the methylation status of miR-137 using one TCGA data and three GEO data sets. A clinical validation cohort of 78 samples was analyzed using MSP for miR-137 promoter methylation. Various in vitro molecular/cellular and animal experiments were conducted to elucidate miR-137's role in CRC. Bioinformatic analysis indicated frequent methylation of miR-137 in CRC tissues, correlating with suppressed expression. EZH2-mediated H3K27 trimethylation silences miR-137 in CRC cells by increasing chromatin compaction, reversible by EZH2 siRNA or inhibitor GSK343. miR-137 inhibits CRC cell proliferation, migration, invasion, and xenograft tumor growth, confirming its tumor-suppressive role. Using the miRWalk repository showed that miR-137 regulates the Wnt signaling pathway by reducing typical protein expression in HCT116 and SW480 cells. miR-137 directly targets RNF4, leading to its downregulation at transcriptional and protein levels, with an observed inverse correlation in CRC tissues. miR-137 accelerates c-Myc and β-catenin degradation by inhibiting RNF4, impacting protein stability and Wnt pathway inhibition. miR-137 is epigenetically silenced through DNA methylation and EZH2-mediated H3K27 trimethylation. It regulates the Wnt signaling pathway by targeting RNF4, leading to c-Myc and β-catenin destabilization. Restoring miR-137 or inhibiting RNF4 suppresses CRC cell proliferation, migration, invasion, and tumor growth, highlighting its therapeutic potential in CRC.

miR-137 regulates autophagy and apoptosis in duodenal ulcer by targeting BNIP3L

BACKGROUND

Duodenal ulcer (DU) represents a clinical manifestation and disease state that occurs when the mucosal surface of the duodenum is damaged. The processes of autophagy and apoptosis have been linked to the development of DU, yet the precise roles they play remain unclear. This study aimed to investigate the expression and mechanism of action of microRNAs (miRNA)-137 (miR-137) in DU.

METHODS

Dysregulated miRNAs and targeted genes were identified from the Gene Expression Omnibus database, and the immune cell infiltration levels were analyzed using CIBERSORT. To confirm the targeting of the miRNAs, we conducted dual luciferase reporter assays in vitro. The detection of cell apoptosis was conducted using flow cytometry. Moreover, quantitative reverse transcription polymerase chain reaction, cell counting kit-8, and Western blot were employed to ascertain the levels of autophagy- and apoptosis-related proteins.

RESULTS

Bioinformatics analysis identified 5 miRNAs, with miR-137 showing the most pronounced dysregulation. Its target gene, BNIP3L, was subsequently identified. In vitro experiments confirmed that miR-137 targeted BNIP3L. The upregulation of miR-137 expression in HIEC-6 cells resulted in the inhibition of BNIP3L expression, a reduction in autophagy, and an increase in apoptosis. A reduction in the expression of miR-137 would have the opposite effect.

CONCLUSIONS

miR-137 is upregulated in DU patients and contributes to ulcer progression by inhibiting BNIP3L, reducing autophagy, and promoting apoptosis. Targeting miR-137 could provide a novel therapeutic strategy for DU management.

Staphylococcal Enterotoxin C2 Mutant-Induced Antitumor Immune Response Is Controlled by CDC42/MLC2-Mediated Tumor Cell Stiffness

As a biological macromolecule, the superantigen staphylococcal enterotoxin C2 (SEC2) is one of the most potent known T-cell activators, and it induces massive cytotoxic granule production. With this property, SEC2 and its mutants are widely regarded as immunomodulating agents for cancer therapy. In a previous study, we constructed an MHC-II-independent mutant of SEC2, named ST-4, which exhibits enhanced immunocyte stimulation and antitumor activity. However, tumor cells have different degrees of sensitivity to SEC2/ST-4. The mechanisms of immune resistance to SEs in cancer cells have not been investigated. Herein, we show that ST-4 could activate more powerful human lymphocyte granule-based cytotoxicity than SEC2. The results of RNA-seq and atomic force microscopy (AFM) analysis showed that, compared with SKOV3 cells, the softer ES-2 cells could escape from SEC2/ST-4-induced cytotoxic T-cell-mediated apoptosis by regulating cell softness through the CDC42/MLC2 pathway. Conversely, after enhancing the stiffness of cancer cells by a nonmuscle myosin-II-specific inhibitor, SEC2/ST-4 exhibited a significant antitumor effect against ES-2 cells by promoting perforin-dependent apoptosis and the S-phase arrest. Taken together, these data suggest that cell stiffness could be a key factor of resistance to SEs in ovarian cancer, and our findings may provide new insight for SE-based tumor immunotherapy.

Vertical level of blood cell division cycle 42 predicts response and survival benefits to PD-1 inhibitor-based regimen in metastatic colorectal cancer patients

Cell division cycle 42 (CDC42) regulates the development of colorectal cancer (CRC) by modulating cancer malignant behaviors and facilitating immune escape. Hence, this study aimed to explore the correlation of blood CDC42 with treatment response and survival benefit to programmed cell death-1 (PD-1) inhibitor-based regimens in inoperable metastatic CRC (mCRC) patients. Fifty-seven inoperable mCRC patients who received PD-1 inhibitor-based regimens were recruited. The CDC42 in peripheral blood mononuclear cell (PBMC) was detected using RT-qPCR in inoperable mCRC patients at baseline and after 2-cycle treatment. Besides, PBMC CDC42 in 20 healthy controls (HCs) was also detected. CDC42 was higher in inoperable mCRC patients compared to HCs (p < 0.001). Elevated CDC42 was related to a higher performance status score (p = 0.034), multiple metastatic sites (p = 0.028), and the presence of liver metastasis (p = 0.035) in inoperable mCRC patients. During the 2-cycle treatment, CDC42 was reduced (p < 0.001). Higher CDC42 at baseline (p = 0.016) and after 2-cycle treatment (p = 0.002) were both linked with decreased objective response rate. CDC42 high at baseline was related to shorter progression-free survival (PFS) (p = 0.015) and overall survival (OS) (p = 0.050). Moreover, CDC42 high after 2-cycle treatment was also related to unfavorable PFS (p < 0.001) and OS (p = 0.001). After adjustment using multivariate Cox's analyses, CDC42 high after 2-cycle treatment independently related to shorter PFS (hazard ratio (HR): 4.129, p < 0.001), and CDC42 reduction ≤230% also independently correlated with shorter OS (HR: 4.038, p < 0.001). The longitudinal change of blood CDC42 during PD-1 inhibitor-based regimen estimates treatment response and survival in inoperable mCRC patients.

Myeloid derived suppressor cells in tumor microenvironment: Interaction with innate lymphoid cells

Human myeloid-derived suppressor cells (MDSC) represent a stage of immature myeloid cells and two main subsets can be identified: monocytic and polymorphonuclear. MDSC contribute to the establishment of an immunosuppressive tumor microenvironment (TME). The presence and the activity of MDSC in patients with different tumors correlate with poor prognosis. As previously reported, MDSC promote tumor growth and use different mechanisms to suppress the immune cell-mediated anti-tumor activity. Immunosuppression mechanisms used by MDSC are broad and depend on their differentiation stage and on the pathological context. It is known that some effector cells of the immune system can play an important role in the control of tumor progression and metastatic spread. In particular, innate lymphoid cells (ILC) contribute to control tumor growth representing a potential, versatile and, immunotherapeutic tool. Despite promising results obtained by using new cellular immunotherapeutic approaches, a relevant proportion of patients do not benefit from these therapies. Novel strategies have been investigated to overcome the detrimental effect exerted by the immunosuppressive component of TME (i.e. MDSC). In this review, we summarized the characteristics and the interactions occurring between MDSC and ILC in different tumors discussing how a deeper knowledge on MDSC biology could represent an important target for tumor immunotherapy capable of decreasing immunosuppression and enhancing anti-tumor activity exerted by immune cells.

miR-137 modulates coelomocytes autophagy by targeting Atg13 in the sea cucumber Apostichopus japonicus

MicroRNAs (miRNAs), as important regulators of host immune responses, play an crucial position in the interaction between host and pathogen by inhibiting the target gene's transcriptional and post-transcriptional expression. A well-validated tumor suppressor, Previously, miR-137 was found to be variably expressed in the sick sea cucumber Apostichopus japonicus specimens by high-throughput sequencing. To further investigate the mechanism of miR-137 regulation of SUS, we identified Atg13 from sea cucumber by dual luciferase reporter assay and RACE (designated as AjAtg13) and was able to serve as a target gene for miR-137. The full-length cDNA of AjAtg13 is a 2197 bp fragment containing an ORF (open reading frame) of 1149 bp and encodes a total of 382 amino acid polypeptides with a predicted molecular weight of 41.7 kDa. Further expression profiling analysis showed increased mRNA levels of AjAtg13 and reduced expression levels of miR-137 in LPS-stimulated sea cucumber coelomocytes, hinting that miR-137 may negatively regulate AjAtg13. MiR-137 targets AjAtg13 through binding to the 3'UTR region by dual-luciferase reporter gene analysis. MiR-137 overexpression in coelomocytes repressed the expression of autophagy related genes, such as AjAtg13, AjLC3, at the same time, it significantly inhibited autophagy and reduced the ability to clear Vibrio splendidus. Conversely, inhibition of miR-137 significantly upregulated the expression of AjAtg13, promoted autophagy and increased clearance of V. splendidus. Subsequent interference with AjAtg13 also significantly inhibits autophagy. In summary, our results suggested that miR-137 could promote coelomocytes autophagy to restrict bacterial invasion by aiming at AjAtg13 in pathogen-stimulated sea cucumbers.

The Process of Filopodia Induction during HPV Infection

Human Papillomavirus 16 (HPV16) infects mucosal and epithelial cells and has been identified as a high-risk HPV type that is an etiologic agent of human cancers. The initial infectious process, i.e., the binding of the virus particle and its entry into the host cell, has been studied extensively, although it is not fully understood. There is still a gap in understanding the steps by which the virus is able to cross the plasma membrane after receptor binding. In this study, we demonstrate that after HPV16 comes into contact with a plasma membrane receptor, there are cytoskeletal changes resulting in an increase of filopodia numbers. This increase in filopodia numbers was transient and was maintained during the first two hours after virus addition. Our data show that there is a statistically significant increase in infection when filopodia numbers are increased by the addition of drug and virus simultaneously, and a decrease in virus infection when filopodia formation is inhibited. We describe that HPV16 binding results in the activation of Cdc42 GTPase that in turn results in an increase in filopodia. siRNA directed at Cdc42 GTPase resulted in a statistically significant reduction of infection and a corresponding lack of filopodia induction.

RHO GTPase-Related Long Noncoding RNAs in Human Cancers

RHO GTPases are critical signal transducers that regulate cell adhesion, polarity, and migration through multiple signaling pathways. While all these cellular processes are crucial for the maintenance of normal cell homeostasis, disturbances in RHO GTPase-associated signaling pathways contribute to different human diseases, including many malignancies. Several members of the RHO GTPase family are frequently upregulated in human tumors. Abnormal gene regulation confirms the pivotal role of lncRNAs as critical gene regulators, and thus, they could potentially act as oncogenes or tumor suppressors. lncRNAs most likely act as sponges for miRNAs, which are known to be dysregulated in various cancers. In this regard, the significant role of miRNAs targeting RHO GTPases supports the view that the aberrant expression of lncRNAs may reciprocally change the intensity of RHO GTPase-associated signaling pathways. In this review article, we summarize recent advances in lncRNA research, with a specific focus on their sponge effects on RHO GTPase-targeting miRNAs to crucially mediate gene expression in different cancer cell types and tissues. We will focus in particular on five members of the RHO GTPase family, including RHOA, RHOB, RHOC, RAC1, and CDC42, to illustrate the role of lncRNAs in cancer progression. A deeper understanding of the widespread dysregulation of lncRNAs is of fundamental importance for confirmation of their contribution to RHO GTPase-dependent carcinogenesis.

The role of noncoding RNAs in pituitary adenoma

Pituitary adenomas (PAs) are common cranial tumors that affect the quality of life in patients. Early detection of PA is beneficial for avoiding clinical complications of this disease and increasing the quality of life. Noncoding RNAs, including long noncoding RNA, miRNA and circRNA, regulate protein expression, mostly by inhibiting the translation process. Studies have shown that dysregulation of noncoding RNAs is associated with PA. Hence understanding the expression pattern of noncoding RNAs can be considered a promising method for developing biomarkers. This article reviews data on the expression pattern of dysregulated noncoding RNAs involved in PA. Possible molecular mechanisms by which the dysregulated noncoding RNA could possibly induce PA are also described.

lncRNA DSCR8 mediates miR-137/Cdc42 to regulate gastric cancer cell proliferation, invasion, and cell cycle as a competitive endogenous RNA

lncRNA DSCR8 (Down syndrome critical region 8) is involved in progression of many cancers, but its specific role in gastric cancer (GC) is still unclear. Here, qRT-PCR detected upregulated expression of DSCR8 and Cdc42 and downregulated expression of miR-137 in GC. The protein expression level of Cdc42 in GC was upregulated as tested by western blot. Statistical analysis showed that DSCR8 was closely associated with some malignant clinicopathological features (such as tumor size, metastasis, and stage) in GC patients. Fluorescence in situ hybridization showed that DSCR8 was localized in the nucleus and cytoplasm. Dual-luciferase reporter gene, RNA immunoprecipitation, and biotin pull-down assays showed that DSCR8 could bind to miR-137 could bind to Cdc42. In vitro and in vivo assays showed that DSCR8 could promote proliferation, invasion, and the cycle of GC cells and inhibit cell apoptosis. In addition, a rescue experiment showed that DSCR8 regulated progression of GC cells via miR-137. Furthermore, DSCR8 regulated Cdc42 in GC cells by inhibiting miR-137. Taken together, these data indicated that DSCR8 could adsorb miR-137 to reduce its inhibitory effect on Cdc42 expression, thereby promoting the progression of GC cells and regulating the cell cycle. These results provide a novel direction for DSCR8 as a target of GC.

Suppression of ANT2 by miR-137 Inhibits Prostate Tumorigenesis

Prostate cancer (PCa) is a serious disease that affects men’s health. To date, no effective and long-lasting treatment option for this condition is available in clinical practice. ANT2 is highly expressed in a variety of hormone-related cancers, but its relationship and regulatory mechanism with PCa are unclear. In this study, we found that ANT2 expression was significantly upregulated in PCa tissues relative to control samples. Genetic knockdown of ANT2 effectively inhibited, while overexpression promoted, proliferation, migration, and invasion of PCa cells. In addition, miR-137 expression was reduced in prostate cancer tissues relative to control tissues. We identified a regulatory site for miR-137 in the 3′-UTR of ANT2 mRNA; luciferase reporter assays indicated that ANT2 is a direct target gene for miR-137. Transfecting cells with miR-137 mimics and/or an ANT2-encoding plasmid revealed that ANT2 promotes proliferation, migration, and invasion of PCa, whereas co-expression of miR-137 mimics inhibited these behaviors. These observations suggest that miR-137 mimics inhibit development of PCa by antagonizing expression of ANT2. Furthermore, tumorigenic assays in nude mice showed that miR-137 inhibitors abolished the inhibitory effect of ANT2 knockdown on PCa tumor growth. Collectively, our findings suggest that ANT2, a target gene of miR-137, is intimately involved in development of PCa, providing new evidence for the mechanism underlying pathogenesis of PCa as well as new options for targeted therapy.

MiR-137 Targets the 3' Untranslated Region of MSH2: Potential Implications in Lynch Syndrome-Related Colorectal Cancer

Mismatch Repair (MMR) gene dysregulation plays a fundamental role in Lynch Syndrome (LS) pathogenesis, a form of hereditary colorectal cancer. Loss or overexpression of key MMR genes leads to genome instability and tumorigenesis; however, the mechanisms controlling MMR gene expression are unknown. One such gene, MSH2, exerts an important role, not only in MMR, but also in cell proliferation, apoptosis, and cell cycle control. In this study, we explored the functions and underlying molecular mechanisms of increased MSH2 expression related to a c.*226A>G variant in the 3'untranslated (UTR) region of MSH2 that had been previously identified in a subject clinically suspected of LS. Bioinformatics identified a putative binding site for miR-137 in this region. To verify miRNA targeting specificity, we performed luciferase gene reporter assays using a MSH2 3'UTR psiCHECK-2 vector in human SW480 cells over-expressing miR-137, which showed a drastic reduction in luciferase activity (p > 0.0001). This effect was abolished by site-directed mutagenesis of the putative miR-137 seed site. Moreover, in these cells we observed that miR-137 levels were inversely correlated with MSH2 expression levels. These results were confirmed by results in normal and tumoral tissues from the patient carrying the 3'UTR c.*226A>G variant in MSH2. Finally, miR-137 overexpression in SW480 cells significantly suppressed cell proliferation in a time- and dose-dependent manner (p < 0.0001), supporting a role for MSH2 in apoptosis and cell proliferation processes. Our findings suggest miR-137 helps control MSH2 expression via its 3'UTR and that dysregulation of this mechanism appears to promote tumorigenesis in colon cells.

ssc-miR-185 targets cell division cycle 42 and promotes the proliferation of intestinal porcine epithelial cell

OBJECTIVE

microRNAs (miRNAs) can play a role in a variety of physiological and pathological processes, and their role is achieved by regulating the expression of target genes. Our previous high-throughput sequencing found that ssc-miR-185 plays an important regulatory role in piglet diarrhea, but its specific target genes and functions in intestinal porcine epithelial cell (IPEC-J2) are still unclear. We intended to verify the target relationship between porcine miR-185 and cell division cycle 42 (CDC42) gene in IPEC-J2 and to explore the effect of miR-185 on the proliferation of IPEC-J2 cells.

METHODS

The TargetScan, miRDB, and miRanda software were used to predict the target genes of porcine miR-185, and CDC42 was selected as a candidate target gene. The CDC423' UTR-wild type (WT) and CDC42-3'UTR-mutant type (MUT) segments were successfully cloned into pmirGLO luciferase vector, and the luciferase activity was detected after co-transfection with miR-185 mimics and pmirGLO-CDC42-3'UTR. The expression level of CDC42 was analyzed using quantitative polymerase chain reaction and Western blot. The proliferation of IPEC-J2 was detected using cell counting kit-8 (CCK-8), methylthiazolyldiphenyltetrazolium bromide (MTT), and 5-ethynyl-2'-deoxyuridine (EdU) assays.

RESULTS

Double enzyme digestion and sequencing confirmed that CDC42-3'UTR-WT and CDC42-3'UTR-MUT were successfully cloned into pmirGLO luciferase reporter vector, and the luciferase activity was significantly reduced after co-transfection with miR-185 mimics and CDC42-3'UTR-WT. Further we found that the mRNA and protein expression level of CDC42 were down-regulated after transfection with miR-185 mimics, while the opposite trend was observed after transfection with miR-185 inhibitor (p<0.01). In addition, the CCK-8, MTT, and EdU results demonstrated that miR-185 promotes IPEC-J2 cells proliferation by targeting CDC42.

CONCLUSION

These findings indicate that porcine miR-185 can directly target CDC42 and promote the proliferation of IPEC-J2 cells. However, the detailed regulatory mechanism of miR-185/CDC42 axis in piglets' resistance to diarrhea is yet to be elucidated in further investigation.

Regulators at Every Step-How microRNAs Drive Tumor Cell Invasiveness and Metastasis

Tumor cell invasiveness and metastasis are the main causes of mortality in cancer. Tumor progression is composed of many steps, including primary tumor growth, local invasion, intravasation, survival in the circulation, pre-metastatic niche formation, and metastasis. All these steps are strictly controlled by microRNAs (miRNAs), small non-coding RNA that regulate gene expression at the post-transcriptional level. miRNAs can act as oncomiRs that promote tumor cell invasion and metastasis or as tumor suppressor miRNAs that inhibit tumor progression. These miRNAs regulate the actin cytoskeleton, the expression of extracellular matrix (ECM) receptors including integrins and ECM-remodeling enzymes comprising matrix metalloproteinases (MMPs), and regulate epithelial-mesenchymal transition (EMT), hence modulating cell migration and invasiveness. Moreover, miRNAs regulate angiogenesis, the formation of a pre-metastatic niche, and metastasis. Thus, miRNAs are biomarkers of metastases as well as promising targets of therapy. In this review, we comprehensively describe the role of various miRNAs in tumor cell migration, invasion, and metastasis.

MiR-29a inhibits cell proliferation and migration by targeting the CDC42/PAK1 signaling pathway in cervical cancer

Cervical cancer is the second most common gynecological malignancy worldwide and the tumorigenesis mechanisms of cervical cancer are still unclear. This study aimed to reveal the role of miR-29a in cervical cancer. The expression level of miR-29a and CDC42 was measured using qRT-PCR. Cell proliferation, apoptosis, migration, and invasion were detected using colony formation, flow cytometry analysis, wound-healing assay, and Transwell assay, respectively. Luciferase reporter assay was used to determine the binding of miR-29a with CDC42. CDC42/p21-activated kinase 1 (PAK1) pathway-related proteins were measured by western blotting. MiR-29a was downregulated and CDC42 was upregulated in cervical cancer cells. Luciferase reporter assay showed that miR-29a negatively regulated the expression of CDC42 by directly targeting 3'-UTR of CDC42. Cell proliferation, migration, and invasion were markedly inhibited, whereas cell apoptosis was significantly increased in Hela and CaSki cells transfected with miR-29a mimics. These effects were partly recovered by CDC42 overexpression. Protein levels of PAK1, p-PAK1, p-LIMK, and p-cofilin were significantly downregulated by miR-29a mimics, which was reversed by CDC42 overexpression and was increased by the miR-29a inhibitor. MiR-29a inhibited cell proliferation, migration, and invasion, as well as promoted cell apoptosis through repressing the PAK1/LIMK signaling pathway by targeting CDC42 in cervical cancer.

A Distinctive microRNA (miRNA) Signature in the Blood of Colorectal Cancer (CRC) Patients at Surgery

Background: Liquid biopsy (LB) provides an examination of the peripheral blood of cancer patients for circulating tumor cells, cell-free nucleic acids and microRNAs (miRNAs) and is an established tool of precision medicine. Unlike most previous LB studies that focused on advanced metastatic colorectal cancer (CRC), we assessed miRNA dysregulation in blood samples obtained on the day of surgery from patients with primary CRC lesions but no clinical evidence of extra-colonic diffusion. In this study, plasma preparation included miRNAs associated to exosomes, but excluded large macrovesicles from the preparation. Methods: The miRNA profile in plasma isolated from a cohort of 35 CRC patients at the day of surgery was analyzed by Next Generation Sequencing (NGS) and further confirmed by droplet digital RT-PCR (dd-RT-PCR). Results: A miR-141-3p/miR-221-3p/miR-222-3p upregulation signature previously described in advanced CRC did not discriminate the analyzed early-CRC cohort from six tumor-free donors (Tf-D). In contrast, NGS-based miRNome analysis of a training cohort of five CRC and three tumor-free donors identified a novel, distinct nine miRNA signature comprising five up-regulated and four down-regulated miRNAs, six of which could be confirmed in the full CRC and tumor-free donor validation dataset by dd-RT-PCR. Additionally, a KRAS (Kirsten Rat Sarcoma Viral Oncogene Homolog) mutant status was correlated with the plasma content of three identified miRNAs. Conclusions: When the data obtained were comparatively evaluated, at least one of the miRNAs belonging to the signature list was found to be dysregulated in 34/35 (97.1%) of our early-CRC plasma samples. The miRNA list provides diagnostic markers as well as possible molecular targets for protocols focusing on “microRNA therapeutics”.

The Role of microRNAs in Organismal and Skin Aging

The aging process starts directly after birth and lasts for the entire lifespan; it manifests itself with a decline in an organism’s ability to adapt and is linked to the development of age-related diseases that eventually lead to premature death. This review aims to explore how microRNAs (miRNAs) are involved in skin functioning and aging. Recent evidence has suggested that miRNAs regulate all aspects of cutaneous biogenesis, functionality, and aging. It has been noted that some miRNAs were down-regulated in long-lived individuals, such as let-7, miR-17, and miR-34 (known as longevity-related miRNAs). They are conserved in humans and presumably promote lifespan prolongation; conversely, they are up-regulated in age-related diseases, like cancers. The analysis of the age-associated cutaneous miRNAs revealed the increased expression of miR-130, miR-138, and miR-181a/b in keratinocytes during replicative senescence. These miRNAs affected cell proliferation pathways via targeting the p63 and Sirtuin 1 mRNAs. Notably, miR-181a was also implicated in skin immunosenescence, represented by the Langerhans cells. Dermal fibroblasts also expressed increased the levels of the biomarkers of aging that affect telomere maintenance and all phases of the cellular life cycle, such as let-7, miR-23a-3p, 34a-5p, miR-125a, miR-181a-5p, and miR-221/222-3p. Among them, the miR-34 family, stimulated by ultraviolet B irradiation, deteriorates collagen in the extracellular matrix due to the activation of the matrix metalloproteinases and thereby potentiates wrinkle formation. In addition to the pro-aging effects of miRNAs, the plausible antiaging activity of miR-146a that antagonized the UVA-induced inhibition of proliferation and suppressed aging-related genes (e.g., p21WAF-1, p16, and p53) through targeting Smad4 has also been noticed. Nevertheless, the role of miRNAs in skin aging is still not fully elucidated and needs to be further discovered and explained.

Down-regulation of FTX promotes the differentiation of osteoclasts in osteoporosis through the Notch1 signaling pathway by targeting miR-137

BACKGROUND

Osteoporosis (OP) is one of the commonly seen bone diseases with low bone mineral densities and trauma fractures. Accumulative studies have demonstrated that the occurrence of OP is closely related to osteoclasts differentiation. LncRNA FTX has been demonstrated to inhibit the development of some human cancers. However, its potential functions in human OP remains to be elusive.

METHODS

The expressions of FTX and miR-137 in bone and serum samples of patients with or without OP were measured. Bioinformatics analysis, RIP assays and luciferase reporter assays were performed to examine the upstream and downstream transactional factors of miR-137. Functional assays were conducted to check the roles of the Notching1 signaling pathway OP.

RESULTS

FTX was suppressed in OP samples and serums, however, miR-137 was greatly elevated. FTX reduced osteoclast-genesis and inhibited osteogenic differentiation by targeting miR-137. This also inhibited the Notch1 signaling pathway.

CONCLUSION

Our experiments and results pointed out that lncRNA FTX up-regulated miR-137 in OP through the Notch1 signaling pathway.

The roles of miRNAs' clinical efficiencies in the colorectal cancer pathobiology: A review article

MiRNAs (microRNAs) are defined as micro directors and regulators of gene expression. Since altered miRNA expression is signified in the pathobiology of diverse cancers such as colorectal cancers (CRCs), these molecules are described as therapeutic targets, either. Manipulation of miRNAs could lead to further therapy for chemo and radio-resistant CRCs. The usage of microRNAs has indicated prominent promise in the prognosis and diagnosis of CRC, because of their unique expression pattern associated with cancer types and malignancies. Nowadays, many researchers are analyzing the correlation between miRNA polymorphisms and cancer risk. With continuous incompatibility in colorectal cancer (CRC) miRNAs expression data, it is critical to move toward the content of a "pre-laboratory" analysis to speed up efficient accuracy medicine and translational study. Pathway study for the highest expressed miRNAs- regulated target genes resulted in the identification of a considerable number of genes associated with CRC pathway including PI3K, TGFβ, and APC. In this review, we aimed to collect fruitful information about miRNAs and their potential roles in CRC, and provide a meta-analysis of the most frequently studied miRNAs in association with the disease.

Identification of the Potential Prognostic Markers from the miRNA-lncRNA-mRNA Interactions for Metastatic Renal Cancer via Next-Generation Sequencing and Bioinformatics

The survival rate in patients with metastatic renal cell carcinoma (RCC) is low. In addition, metastatic RCC resists traditional treatment. Therefore, identification of novel biomarkers, signaling pathways, and therapeutic targets is an important issue. The aim of the present study is to identify novel prognostic markers from the miRNA-mediated network for the regulation of metastasis of RCC. To address this issue, the RNA of human RCC cell lines, 786-O and ACHN, derived from primary and metastatic sites, respectively, were collected and subjected to RNA sequencing and small RNA sequencing. The bioinformatic analysis revealed that the pathways of the genes with different expressions were related to tumor progression, and identified miRNA and miRNA-long non-coding RNA (lncRNA) interactions, and mRNA. The results revealed that the expressions of seven miRNAs were associated with the overall survival rate of patients with RCC. Furthermore, the expressions of two lncRNA and three protein-coding genes (mRNA) were significantly associated with the increased or decreased disease-free survival rate. Although the detailed regulatory mechanism between miRNAs and targeted genes was not fully understood, our findings present novel prognostic markers and novel insight on miRNA-mediated pathways for metastatic RCC.

Extensive transcriptional responses are co-ordinated by microRNAs as revealed by Exon-Intron Split Analysis (EISA)

Epithelial-mesenchymal transition (EMT) has been a subject of intense scrutiny as it facilitates metastasis and alters drug sensitivity. Although EMT-regulatory roles for numerous miRNAs and transcription factors are known, their functions can be difficult to disentangle, in part due to the difficulty in identifying direct miRNA targets from complex datasets and in deciding how to incorporate 'indirect' miRNA effects that may, or may not, represent biologically relevant information. To better understand how miRNAs exert effects throughout the transcriptome during EMT, we employed Exon-Intron Split Analysis (EISA), a bioinformatic technique that separates transcriptional and post-transcriptional effects through the separate analysis of RNA-Seq reads mapping to exons and introns. We find that in response to the manipulation of miRNAs, a major effect on gene expression is transcriptional. We also find extensive co-ordination of transcriptional and post-transcriptional regulatory mechanisms during both EMT and mesenchymal to epithelial transition (MET) in response to TGF-β or miR-200c respectively. The prominent transcriptional influence of miRNAs was also observed in other datasets where miRNA levels were perturbed. This work cautions against a narrow approach that is limited to the analysis of direct targets, and demonstrates the utility of EISA to examine complex regulatory networks involving both transcriptional and post-transcriptional mechanisms.

MicroRNAs involved in innate immunity regulation in the sea cucumber: A review

The sea cucumber is one of the most economically significant echinoderms. The immunity against exogenous stimulation of sea cucumber is of great academic and economic importance. MicroRNAs (miRNAs) are a class of short endogenous non-coding RNAs (ncRNAs) that are considered as vital regulators of both innate and adaptive immune responses in most eukaryotes. In sea cucumbers, some miRNAs (such as miR-133, miR-137, and miR-2008, among others) that participate in the regulation of innate immunity have been recently identified and characterized. This review focuses on those known miRNAs and their corresponding target genes that participate in the regulation of the complement system, Toll-like receptor (TLR) pathway, reactive oxygen species (ROS) production and apoptosis pathways in sea cucumbers. Moreover, we cover immune-related miRNA investigations in sea cucumbers that provide insights into developing more miRNA-based biomarkers and therapeutic strategies for sea cucumber diseases.

Panax notoginseng saponins radiosensitize colorectal cancer cells by regulating the SNHG6/miR-137 axis

Panax notoginseng saponins (PNS) have recently attracted great attention for their anti-cancer activity in colorectal cancer (CRC). The aim of this study was to explore the functional role and underlying mechanisms of PNS on CRC radiosensitivity. Cell viability was assessed by a Cell Counting kit-8 assay. Cell survival and apoptosis were determined using colony formation assay and flow cytometry, respectively. Quantitative real-time PCR was used to quantify the levels of SNHG6 and miR-137. The targeted correlation between SNHG6 and miR-137 was validated by dual-luciferase reporter and RNA immunoprecipitation assays. Our data supported that PNS weakened the viability of CRC cells. Moreover, PNS promoted the radiosensitivity of CRC cells. Mechanistically, PNS enhanced CRC cell radiosensitivity by upregulating SNHG6. SNHG6 directly targeted miR-137 and inhibited miR-137 expression. MiR-137 was involved in the regulatory effect of SNHG6 on CRC cell radiosensitivity. Furthermore, PNS increased miR-137 expression through SNHG6 in CRC cells. Our study suggested that PNS promoted radiosensitivity in CRC cells at least partly through regulating the SNHG6/miR-137 axis, providing a novel understanding of the anti-cancer mechanism of PNS in CRC.

The Differential DNA Hypermethylation Patterns of microRNA-137 and microRNA-342 Locus in Early Colorectal Lesions and Tumours

Colorectal cancer (CRC) is the third most commonly diagnosed cancer worldwide, representing 13% of all cancers. The role of epigenetics in cancer diagnosis and prognosis is well established. MicroRNAs in particular influence numerous cancer associated processes including apoptosis, proliferation, differentiation, cell-cycle controls, migration/invasion and metabolism. MiRNAs-137 and 342 are exon- and intron-embedded, respectively, acting as tumour-suppressive microRNA via hypermethylation events. Levels of miRNAs 137 and 342 have been investigated here as potential prognostic markers for colorectal cancer patients. The methylation status of miRNA-137 and miRNA-342 was evaluated using methylation-specific (MSP) polymerase chain reaction (PCR) on freshly frozen tissue derived from 51 polyps, 8 tumours and 14 normal colon mucosa specimens. Methylation status of miRNA-137 and miRNA-342 was significantly higher in tumour lesions compared to normal adjacent mucosa. Surprisingly, the methylation frequency of miR-342 (76.3%) among colorectal cancer patients was significantly higher compared to miR-137 (18.6%). Furthermore, normal tissues, adjacent to the lesions (N-Cs), displayed no observable methylation for miRNA-137, whereas 27.2% of these N-Cs showed miRNA-342 hypermethylation. MiRNA-137 hypermethylation was significantly higher in male patients and miR-342 hypermethylation correlated with patient age. Methylation status of miRNA-137 and miRNA-342 has both diagnostic and prognostic value in CRC prediction and prevention.

miR-552-5p facilitates osteosarcoma cell proliferation and metastasis by targeting WIF1

miR-552 promotes tumor growth and metastasis in colorectal cancer. However, the function of miR-552 in osteosarcoma remains unclear. The current study investigated the role and mechanism of miR-552-5p in the proliferation, migration and invasion of osteosarcoma cells. miR-552-5p was significantly upregulated in osteosarcoma tissues and cell lines compared with adjacent normal tissues and normal osteoblast cells. Knockdown of miR-552-5p significantly reduced the proliferation of MG63 and U2OS cells, and inhibited cell migration and invasion. Wnt inhibitory factor 1 (WIF1) was the direct target gene of miR-552-5p in osteosarcoma cells. Overexpression of miR-552-5p markedly decreased the expression of WIF1 in MG63 and U2OS cells. A negative association was identified between the expression levels of miR-552-5p and WIF1 in osteosarcoma tissues. Furthermore, the expression of WIF1 was downregulated in osteosarcoma tissues and cell lines. Finally, knockdown of WIF1 in MG63 and U2OS cells treated with miR-552-5p inhibitors rescued their ability to proliferate, migrate and invade. Overall, the results indicated that miR-552-5p promoted osteosarcoma development and progression by inhibiting WIF1. Therefore, miR-552-5p may serve as a new therapeutic target for treatment of patients with osteosarcoma.

Downregulated NOX4 underlies a novel inhibitory role of microRNA-137 in prostate cancer

Prostate cancer is the second highest caused by cancer-related death among males. microRNAs (miRs) have been reported to participate in carcinogenesis, yet their roles in prostate cancer are rarely studied or investigated. Therefore, the present study attempted to explore the effect of miR-137 in prostate cancer via regulating NADPH oxidase 4 (NOX4). Initially, microarray analysis was performed to obtain prostate cancer-related differentially expressed genes and miRs that regulated NOX4, followed by detecting the expression of miR-137 and NOX4 and its target relationship. Moreover, PC-3 cells were transfected with small interfering RNA (siNOX4) and miR-137 mimic for exploring the effect of miR-137 on glycolysis, cell proliferation, and apoptosis in prostate cancer by evaluating lactate production, glucose uptake, adenosine triphosphate (ATP) production, viability rate, and expression of cleaved caspases 3, 8, and 9, cytochrome c, cleaved poly ADP ribose polymerase (PARP), Bax, and Bcl-2. miR-137 was vital to prostate cancer progression via regulating NOX4. Besides, miR-137 expressed poorly while NOX4 expressed highly in prostate cancer. NOX4 was the target gene of miR-137. Additionally, overexpression of miR-137 and silencing of NOX4 were observed to decrease NOX4 and Bcl-2 protein expression, but increase cleaved caspases 3, 8, and 9, cytochrome c, cleaved-PARP, and Bax protein expression. Furthermore, miR-137 overexpression and NOX4 silencing contributed to decreased lactate production, glucose uptake, ATP production, and cell proliferation, but increased apoptosis rate. Collectively, the present study showed that miR-137 repressed glycolysis in prostate cancer through knockdown of NOX4, which might be a potential theoretical target for prostate cancer treatment.

Curcumin alleviates LPS-induced inflammation and oxidative stress in mouse microglial BV2 cells by targeting miR-137-3p/NeuroD1

Curcumin has been reported to exert protective effects on inflammation-related diseases, including spinal cord injury (SCI).

FSTL1 enhances chemoresistance and maintains stemness in breast cancer cells via integrin β3/Wnt signaling under miR-137 regulation

FSTL1 is a protein coding gene associated with cell signaling pathway regulation and the progression of a variety of disorders. In this study, we hypothesized that FSTL1 increases oncogenesis in breast cancer by enhancing stemness and chemoresistance. RT-PCR and IHC revealed significantly higher FSTL1 mRNA and protein levels in TNBC than in non-TNBC specimens and in breast cancer cell lines. We then found that FSTL1 levels were significantly increased in chemoresistant cells. LIVE/DEAD, MTT cell viability and colony formation assays did in fact demonstrate that FSTL1 is required for CDDP and DOX chemoresistance in breast cancer cell lines. FSTL1 overexpression caused significant elevation of stem cell biomarkers, as well as breast cancer cell proliferation. To determine whether the Wnt/β-catenin signaling pathway is involved in the observed effects of FSTL1, we assessed levels of pathway target. TOP/FOP flash, colony formation, and tumor sphere formation assays indicated that FSTL1 activates Wnt/β-catenin signaling through integrin β3. We then sought to identify a microRNA (miRNA) that regulates FSTL1 activity. Luciferase assays demonstrated that miR-137 reduces FSTL1 mRNA and protein levels. Ultimately, our findings indicate that there is an miR-137/FSTL1/integrin β3/Wnt/β-catenin signaling axis in breast cancer cells that regulates stemness and chemoresistance.

miR-200b/c targets the expression of RhoE and inhibits the proliferation and invasion of non-small cell lung cancer cells

Lung cancer is a major cause of mortality worldwide and non‑small cell lung cancer (NSCLC) accounts for ~80% of all cases of lung cancer. Increasing evidence indicates that Rho family GTPase 3 (RhoE) is important in the carcinogenesis and progression of NSCLC. In addition, several studies have indicated that microRNA (miR)‑200b/c is downregulated in NSCLC cells. However, the exact mechanism remains to be elucidated. In the present study, immunohistochemistry (IHC) assays were used to analyze the RhoE and epithelial‑mesenchymal transition (EMT)‑related proteins in NSCLC tissues. Putative target sequences of the RhoE 3' untranslated region (3'UTR) for miR‑200b/c were detected using bioinformatics analysis. The mRNA expression levels of RhoE and miR‑200b/c were determined by reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR) analysis, and western blot analysis was used to detect the protein levels of RhoE in cells. The luciferase‑reporter activity of the RhoE 3'UTR was detected using a dual‑luciferase assay. A cell counting kit‑8 assay, flow cytometry and Transwell assay were used to detect cell proliferation, cell cycle, and invasion and migration ability, respectively. The IHC assays indicated that RhoE was overexpressed in NSCLC tissues. The bioinformatics analysis revealed that the RhoE 3'UTR contained a putative target site for miR‑200b/c, which was conserved across species. The results of RT‑qPCR analysis showed that the mRNA expression of RhoE was overexpressed and miR‑200b/200c was decreased in lung cancer tissues. The enhanced expression of miR‑200b or miR‑200c significantly downregulated the expression of RhoE at the mRNA and protein levels in A549 and NCI‑H1299 NSCLC cells. Furthermore, luciferase assays showed that miR‑200b and miR‑200c directly targeted the 3'UTR of RhoE. The forced expression of miR‑200b or miR‑200c markedly inhibited A549 cell and NCI‑H1299 cell proliferation, G0/G1 progression and cell invasion, which was consistent with the effects of RNA interference‑mediated RhoE knockdown in these cells. The suppression of RhoE regulated the expression of EMT‑related markers, which was consistent with the effect of miR‑200b/c in NSCLC cells, and the expression of EMT‑related proteins and RhoE were also correlated in the lung cancer tissues. Therefore, miR‑200b and miR‑200c targeted the expression of RhoE and inhibited the malignancy of NSCLC cells, and the downregulation of miR‑200b and miR‑200c may contribute to the high expression of RhoE in NSCLC.

miR-185 inhibits cell migration and invasion of hepatocellular carcinoma through CDC42

Hepatocellular carcinoma (HCC) is a primary liver cancer with high incidence and mortality. miR-185, a microRNA with appriximately 22-28 nucleotides, was reported to be involved in many cancers. The potential mechanism of miR-185 on HCC through cell division cycle 42 (CDC42) was investigated. RT-qPCR was used to measure the RNA level of miR-185 and CDC42 in HCC tissues and cells. The dual luciferase reporter assay was used to verify whether CDC42 was a target gene for miR-185. Transwell assay was employed to detect the ability of migration and invasion to change miR-185. miR-185 expression was low in HCC and negatively correlated with CDC42. miR-185 inhibited HCC migration, invasion and miR-185 low expression predicted poor prognosis. CDC42 was predicted to be a target gene for miR-185, and regulated by miR-185. miR-185 suspressed the ability of cell migration and invasion through CDC42 in HCC. In conclusion, miR-185 suspressed migration and invasion of HCC cells by directly targeting CDC42. It is suggested that miR-185/CDC42 axis may present a novel target for HCC treatment.

miR-137 suppresses proliferation, migration and invasion of colon cancer cell lines by targeting TCF4

Colorectal cancer is cancer of the colon or rectum and is the third most prevalent form of cancer. Currently, there are several shortcomings in the prognosis and early detection of colon cancer. The present study aims to address questions pertaining to the role of microRNA (miR)-137 in colon cancer progression and the mode of regulation. The endogenous and over-expressed levels of miR-137 in three colon cancer cell lines were assessed by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The MTT assay was used to assess cell proliferation. Cell migration and invasion assays were assessed using Transwell apparatus and Matrigel invasion chambers. The potential targets of miR-150 were predicted using TargetScan software, and one of the best scoring targets, transcription factor 4 (TCF4), was experimentally validated using western blot analysis and RT-qPCR. It was found that that miR-137 is expressed at extremely low levels in COLO205, HCT116 and SW480 cell lines. Cell proliferation, migration and invasion were inhibited subsequent to transfection of the colon cancer cell lines with miR-137. Using bioinformatics analysis, the best scoring putative targets were identified. One such target, TCF4, was experimentally validated, and it was shown that overexpression of miR-137 suppresses TCF4 in all three colon cancer cell lines. In conclusion, it was shown that miR-137 inhibits cell proliferation, migration and invasion in colon cancer cell lines by negatively regulating the expression of TCF4.

MiR-137 suppresses tumor growth and metastasis in clear cell renal cell carcinoma

BACKGROUND

The most frequent type of renal cell carcinoma is called clear-cell renal cell carcinoma (ccRCC) which is associated with a poor prognosis. It has been observed that miR-137 is aberrantly expressed in many different kinds of human malignancies including ccRCC. This research aims to examine the role of miR-137 in ccRCC.

METHODS

Quantitative RT-PCR (qRT-PCR) was applied to measure miR-137 expression in ccRCC and adjacent noncancerous tissue. Gene expression was determined by western blot. Cell Counting Kit-8 (CCK-8) assay, flow cytometry and Transwell assay were used to determine the effects of miR-137 on cell growth, apoptosis and invasion, respectively. Moreover, xenograft and pulmonary metastasis animal models were established to investigate the role of miR-137 in vivo.

RESULTS

Our findings show that there was significant downregulation of miR-137 in ccRCC tissue relative to corresponding non-cancerous tissue. Ectopic miR-137 expression in ccRCC cells led to suppression of cell growth and invasion, as well as apoptosis induction. In contrast, knockdown of miR-137 enhances proliferation and invasion, inhibits apoptosis. It also confirms that miR-137 plays a tumor supressor role in vivo. Mechanically, miR-137 directly targets the 3'-UTR of RLIP76 which is an established oncogene in ccRCC.

CONCLUSION

MiR-137 serves as a tumor suppressor, which can be considered a potential therapeutic target in ccRCC.

Regulating Cdc42 and Its Signaling Pathways in Cancer: Small Molecules and MicroRNA as New Treatment Candidates

Despite great improvements in the diagnosis and treatment of neoplasms, metastatic disease is still the leading cause of death in cancer patients, with mortality rates still rising. Given this background, new ways to treat cancer will be important for development of improved cancer control strategies. Cdc42 is a member of the Rho GTPase family and plays an important role in cell-to-cell adhesion, formation of cytoskeletal structures, and cell cycle regulation. It thus influences cellular proliferation, transformation, and homeostasis, as well as the cellular migration and invasion processes underlying tumor formation. Cdc42 acts as a collection point for signal transduction and regulates multiple signaling pathways. Moreover, recent studies show that in most human cancers Cdc42 is abnormally expressed and promoting neoplastic growth and metastasis. Regarding possible new treatments for cancer, miRNA and small molecules targeting Cdc42 and related pathways have been recently found to be effective on cancer. In this review, we analyze the newly recognized regulation mechanisms for Cdc42 and Cdc42-related signal pathways, and particularly new treatments using small molecules and miRNAs to inhibit the abnormal overexpression of Cdc42 that may slow down the metastasis process, improve cancer therapy and lead to novel strategies for development of antineoplastic drugs.

Clinical relevance of the transcriptional signature regulated by CDC42 in colorectal cancer

CDC42 is an oncogenic Rho GTPase overexpressed in colorectal cancer (CRC). Although CDC42 has been shown to regulate gene transcription, the specific molecular mechanisms regulating the oncogenic ability of CDC42 remain unknown. Here, we have characterized the transcriptional networks governed by CDC42 in the CRC SW620 cell line using gene expression analysis. Our results establish that several cancer-related signaling pathways, including cell migration and cell proliferation, are regulated by CDC42. This transcriptional signature was validated in two large cohorts of CRC patients and its clinical relevance was also studied. We demonstrate that three CDC42-regulated genes offered a better prognostic value when combined with CDC42 compared to CDC42 alone. In particular, the concordant overexpression of CDC42 and silencing of the putative tumor suppressor gene CACNA2D2 dramatically improved the prognostic value. The CACNA2D2/CDC42 prognostic classifier was further validated in a third CRC cohort as well as in vitro and in vivo CRC models. Altogether, we show that CDC42 has an active oncogenic role in CRC via the transcriptional regulation of multiple cancer-related pathways and that CDC42-mediated silencing of CACNA2D2 is clinically relevant. Our results further support the use of CDC42 specific inhibitors for the treatment of the most aggressive types of CRC.

A comprehensive review of the genetic and biological evidence supports a role for MicroRNA-137 in the etiology of schizophrenia

Since it was first associated with schizophrenia (SCZ) in a 2011 genome-wide association study (GWAS), there have been over 100 publications focused on MIR137, the gene encoding microRNA-137. These studies have examined everything from its fundamental role in the development of mice, flies, and fish to the intriguing enrichment of its target gene network in SCZ. Indeed, much of the excitement surrounding MIR137 is due to the distinct possibility that it could regulate a gene network involved in SCZ etiology, a disease which we now recognize is highly polygenic. Here we comprehensively review, to the best of our ability, all published genetic and biological evidence that could support or refute a role for MIR137 in the etiology of SCZ. Through a careful consideration of the literature, we conclude that the data gathered to date continues to strongly support the involvement of MIR137 and its target gene network in neuropsychiatric traits, including SCZ risk. There remain, however, more unanswered than answered questions regarding the mechanisms linking MIR137 genetic variation with behavior. These questions need answers before we can determine whether there are opportunities for diagnostic or therapeutic interventions based on MIR137. We conclude with a number of suggestions for future research on MIR137 that could help to provide answers and hope for a greater understanding of this devastating disorder.

Endometriosis risk alleles at 1p36.12 act through inverse regulation of CDC42 and LINC00339

Genome-wide association studies (GWAS) have identified markers within the WNT4 region on chromosome 1p36.12 showing consistent and strong association with increasing endometriosis risk. Fine mapping using sequence and imputed genotype data has revealed strong candidates for the causal SNPs within these critical regions; however, the molecular pathogenesis of these SNPs is currently unknown. We used gene expression data collected from whole blood from 862 individuals and endometrial tissue from 136 individuals from independent populations of European descent to examine the mechanism underlying endometriosis susceptibility. Association mapping results from 7,090 individuals (2,594 cases and 4,496 controls) supported rs3820282 as the SNP with the strongest association for endometriosis risk (P = 1.84 × 10−5, OR = 1.244 (1.126-1.375)). SNP rs3820282 is a significant eQTL in whole blood decreasing expression of LINC00339 (also known as HSPC157) and increasing expression of CDC42 (P = 2.0 ×10−54 and 4.5x10−4 respectively). The largest effects were for two LINC00339 probes (P = 2.0 ×10−54; 1.0 × 10−34). The eQTL for LINC00339 was also observed in endometrial tissue (P = 2.4 ×10−8) with the same direction of effect for both whole blood and endometrial tissue. There was no evidence for eQTL effects for WNT4. Chromatin conformation capture provides evidence for risk SNPs interacting with the promoters of both LINC00339 and CDC4 and luciferase reporter assays suggest the risk SNP rs12038474 is located in a transcriptional silencer for CDC42 and the risk allele increases expression of CDC42. However, no effect of rs3820282 was observed in the LINC00339 expression in Ishikawa cells. Taken together, our results suggest that SNPs increasing endometriosis risk in this region act through CDC42, but further functional studies are required to rule out inverse regulation of both LINC00339 and CDC42.

Epigenetic silencing of miR-137 contributes to early colorectal carcinogenesis by impaired Aurora-A inhibition

MicorRNA-137 is silenced in human colorectal cancer tissues and colon polyps. Our study showed that the decreased expression of miR-137 is significantly different in various types of polyp which maintain different potentials to lead to CRC development. The expression of miR-137 gradually decreases during the process of colorectal carcinogenesis. Receiver operating characteristic curve (ROC) analysis indicates that the loss of miR-137 expression in colon polyps can serve as a biomarker to predict the predisposition of colorectal carcinogenesis. By cell model and xenograft animal model, the enforced expression of miR-137 in colorectal cancer cells can inhibit cell proliferation and tumor formation, induce G2/M arrest, and lead to apoptosis. The expression pattern of miR-137 and Aurora-A or PTGS2 is negatively correlated in human colorectal cancer tissues and colon polyps. Those effects induced by overexpressed miR-137 can be rescued by the overexpression of Aurora-A. In summary, our study suggests that the loss of miR-137 expression in colon polyps can serve as a biomarker to predict the tendency toward to CRC formation through the impaired inhibitory effect of Aurora-A. The investigation of the regulatory mechanism of miR-137-mediated Aurora-A inhibition may shed new light on the early prognosis of cancer therapy for CRC in the future.

Knockdown of long non-coding RNA XIST inhibits cell viability and invasion by regulating miR-137/PXN axis in non-small cell lung cancer

Long non-coding RNAs (lncRNAs) may serve as miRNA sponges to modulate the expressions of miRNA target genes. LncRNA X-inactive specific transcript (XIST) has been demonstrated to be upregulated and act as an oncogene in non-small cell lung cancer (NSCLC). However, the sponge role of XIST in NSCLC progression remains largely unknown. In this study, we demonstrated that XIST was substantially upregulated and miR-137 was aberrantly downregulated in NSCLC tissues and cells. XIST was identified to function as a competitive endogenous RNA (ceRNA) for miR-137 to promote NSCLC cell viability and invasion. Additionally, our results suggested that miR-137 targeted the 3'UTR of paxillin (PXN) to suppress NSCLC cell viability and invasion. Meanwhile, miR-137 was negatively correlated with PXN expression while XIST was positively correlated with PXN expression. More importantly, XIST positively regulated PXN levels by sponging miR-137 in vitro and in vivo. Collectively, our study provided the evidence for the cross-talk between XIST, miR-137, and PXN, shedding light on the therapy for NSCLC.

A Panel of Methylated MicroRNA Biomarkers for Identifying High-Risk Patients With Ulcerative Colitis-Associated Colorectal Cancer

BACKGROUND & AIMS

Methylation of specific microRNAs (miRNAs) often occurs in an age-dependent manner, as a field defect in some instances, and may be an early event in colitis-associated carcinogenesis. We aimed to determine whether specific mRNA signature patterns (MIR1, MIR9, MIR124, MIR137, MIR34B/C) could be used to identify patients with ulcerative colitis (UC) who are at increased risk for colorectal neoplasia.

METHODS

We obtained 387 colorectal tissue specimens collected from 238 patients with UC (152 without neoplasia, 17 with dysplasia, and 69 with UC-associated colorectal cancer [UC-CRC]), from 2 independent cohorts in Japan between 2005 and 2015. We quantified methylation of miRNAs by bisulfite pyrosequencing analysis. We analyzed clinical data to determine whether miRNA methylation patterns were associated with age, location, or segment of the colorectum (cecum, transverse colon, and rectum). Differences in tissue miRNA methylation and expression levels were compared among samples and associated with cancer risk using the Wilcoxon, Mann-Whitney, and Kruskal-Wallis tests as appropriate. We performed a validation study of samples from 90 patients without UC and 61 patients with UC-associated dysplasia or cancer to confirm the association between specific methylation patterns of miRNAs in non-tumor rectal mucosa from patients with UC at risk of UC-CRC.

RESULTS

Among patients with UC without neoplasia, rectal tissues had significantly higher levels of methylation levels of MIR1, MIR9, MIR124, and MIR137 than in proximal mucosa; levels of methylation were associated with age and duration of UC in rectal mucosa. Methylation of all miRNAs was significantly higher in samples from patients with dysplasia or CRC compared with samples from patients without neoplasia. Receiver operating characteristic analysis revealed that methylation levels of miRNAs in rectal mucosa accurately differentiated patients with CRC from those without. Methylation of MIR137 in rectal mucosa was an independent risk factor for UC-CRC. Methylation patterns of a set of miRNAs (panel) could discriminate discriminate UC patients with or without dysplasia or CRC in the evaluation cohort (area under the curve, 0.81) and the validation cohort (area under the curve, 0.78).

CONCLUSIONS

In evaluation and validation cohorts, we found specific miRNAs to be methylated in rectal mucosal samples from patients with UC with dysplasia or CRC compared with patients without neoplasms. This pattern also associated with patient age and might be used to identify patients with UC at greatest risk for developing UC-CRC. Our findings provide evidence for a field defect in rectal mucosa from patients with UC-CRC.

Curcumin modulates endothelial permeability and monocyte transendothelial migration by affecting endothelial cell dynamics

Curcumin is a phenolic compound that exhibits beneficial properties for cardiometabolic health. We previously showed that curcumin reduced the infiltration of immune cells into the vascular wall and prevented atherosclerosis development in mice. This study aimed to investigate the effect of curcumin on monocyte adhesion and transendothelial migration (TEM) and to decipher the underlying mechanisms of these actions. Human umbilical vein endothelial cells (HUVECs) were exposed to curcumin (0.5-1μM) for 3h prior to their activation by Tumor Necrosis Factor alpha (TNF-α). Endothelial permeability, monocyte adhesion and transendothelial migration assays were conducted under static condition and shear stress that mimics blood flow. We further investigated the impact of curcumin on signaling pathways and on the expression of genes using macroarrays. Pre-exposure of endothelial cells to curcumin reduced monocyte adhesion and their transendothelial migration in both static and shear stress conditions. Curcumin also prevented changes in both endothelial permeability and the area of HUVECs when induced by TNF-α. We showed that curcumin modulated the expression of 15 genes involved in the control of cytoskeleton and endothelial junction dynamic. Finally, we showed that curcumin inhibited NF-κB signaling likely through an antagonist interplay with several kinases as suggested by molecular docking analysis. Our findings demonstrate the ability of curcumin to reduce monocyte TEM through a multimodal regulation of the endothelial cell dynamics with a potential benefit on the vascular endothelial function barrier.

Roles of microRNAs and RNA-Binding Proteins in the Regulation of Colorectal Cancer Stem Cells

Colorectal cancer stem cells (CSCs) are responsible for the initiation, progression and metastasis of human colorectal cancers, and have been characterized by the expression of cell surface markers, such as CD44, CD133, CD166 and LGR5. MicroRNAs (miRNAs) are differentially expressed between CSCs and non-tumorigenic cancer cells, and play important roles in the maintenance and regulation of stem cell properties of CSCs. RNA binding proteins (RBPs) are emerging epigenetic regulators of various RNA processing events, such as splicing, localization, stabilization and translation, and can regulate various types of stem cells. In this review, we summarize current evidences on the roles of miRNA and RBPs in the regulation of colorectal CSCs. Understanding the epigenetic regulation of human colorectal CSCs will help to develop biomarkers for colorectal cancers and to identify targets for CSC-targeting therapies.

MicroRNA-137 is negatively associated with clinical outcome and regulates tumor development through EZH2 in cervical cancer

We intend to evaluate the expression, clinical relevance, and functional role of microRNA-137 (miR-137) in human cervical cancer (CC). MiR-137 expressions were assessed by qPCR in CC cell lines and human CC tumors. The correlation between endogenous miR-137 expression and CC patients' postoperative overall survival was examined statistically. CC cell lines, Ca-Ski, and SiHa cells were transduced with lentivirus to ectopically upregulate endogenous miR-137 expressions. Possible inhibitory effects of miR-137 upregulation on CC in vitro proliferation and migration, as well as in vivo transplantation were evaluated. Targeting of enhancer of zeste homolog 2 (EZH2) gene by miR-137 in CC was assessed by dual-luciferase activity assay and qPCR. In CC cells with upregulated miR-137, EZH2 was overexpressed to assess its direct function in miR-137 mediated CC proliferation and migration. MiR-137 was downregulated in both CC cells and human CC tumors. Downregulation of endogenous miR-137 was significantly correlated with CC patients' short overall survival. In CC cells, miR-137 upregulation is tumor-suppressive by inhibiting proliferation and migration in vitro, and transplantation in vivo. EZH2 was a direct downstream target gene of miR-137 in CC. Forced overexpression of EZH2 in miR-137-upregulated CC cells reversed the tumor-suppression induced by miR-137. MiR-137 is lowly expressed in CC and possibly acting as a negative biomarker for CC patients' clinical outcome. MiR-137 upregulation may suppress CC, very likely by inversely regulating EZH2.

MicroRNA-761 promotes the sensitivity of colorectal cancer cells to 5-Fluorouracil through targeting FOXM1

Resistance to chemotherapy is a big challenge for treatment of patients with colorectal cancer; however; the mechanism underlying chemoresistance in colorectal cancer cell has not been elucidated. MicroRNAs (miRNAs) are new players in the development of drug chemoresistance. In our study, we indicated that overexpression of miR-761 promoted the sensitivity of colorectal cancer cells to 5-Fluorouracil (5-FU). miR-761 expression was downregulated in colorectal cancer cell lines and tissues. miR-761 expression was lower in patients with low grade than in patients with high grade. In additon, we showed that elevated expression of miR-761 suppressed colorectal cancer cell proliferation, cell cycle, colony formation and cell invasion. We identified that FOXM1 was a direct target gene of miR-761 in colorectal cancer cell. FOXM1 expression was upregulated in colorectal cancer tissues compare to the adjacent non-tumor tissues. MiR-761 expression was negatively associated with the expression of FOXM1 in colorectal cancer tissues. Elevated expression of FOXM1 suppressed the sensitivity of miR-761-overexpressing HT29 cells to 5-FU. We also indicated that FOXM1 overexpression promoted cell proliferation, cycle and invasion of miR-761-overexpressing HT29 cells. These data suggested that miR-761 played a tumor suppressor miRNA in colorectal cancer progression and reduced miR-761 expression might be a major mechanism for 5-FU resistance in colorectal cancer cell.

miR-29a promotes hepatitis B virus replication and expression by targeting SMARCE1 in hepatoma carcinoma

AIM

To investigate the functional role and underlying molecular mechanism of miR-29a in hepatitis B virus (HBV) expression and replication.

METHODS

The levels of miR-29a and SMARCE1 in HBV-infected HepG2.2.15 cells were measured by quantitative real-time PCR and western blot analysis. HBV DNA replication was measured by quantitative PCR and Southern blot analysis. The relative levels of hepatitis B surface antigen and hepatitis B e antigen were detected by enzyme-linked immunosorbent assay. The Cell Counting Kit-8 (CCK-8) was used to detect the viability of HepG2.2.15 cells. The relationship between miR-29a and SMARCE1 were identified by target prediction and luciferase reporter analysis.

RESULTS

miR-29a promoted HBV replication and expression, while SMARCE1 repressed HBV replication and expression. Cell viability detection indicated that miR-29a transfection had no adverse effect on the host cells. Moreover, SMARCE1 was identified and validated to be a functional target of miR-29a. Furthermore, restored expression of SMARCE1 could relieve the increased HBV replication and expression caused by miR-29a overexpression.

CONCLUSION

miR-29a promotes HBV replication and expression through regulating SMARCE1. As a potential regulator of HBV replication and expression, miR-29a could be a promising therapeutic target for patients with HBV infection.

Upregulation of microRNA-137 expression by Slug promotes tumor invasion and metastasis of non-small cell lung cancer cells through suppression of TFAP2C

The epithelial-mesenchymal transition (EMT) regulator, Slug, plays multifaceted roles in controlling lung cancer progression, but its downstream targets and mechanisms in promoting lung cancer progression have not been well defined. In particular, the miRNAs downstream of Slug in non-small cell lung cancer (NSCLC) remain undetermined. Here, we report that miR-137 is downstream of the EMT regulator, Slug, in lung cancer cells. Slug binds directly to the E-box of the miR-137 promoter and up-regulates its expression in lung cancer cells. Knockdown of miR-137 abolished Slug-induced cancer invasion and migration, whereas upregulation of miR-137 was found to trigger lung cancer cell invasion and progression by direct suppressing TFAP2C (transcription factor AP-2 gamma). Clinical data showed that lung adenocarcinoma patients with low-level expression of Slug and miR-137 but high-level expression of TFAP2C experienced significantly better survival. miR-137 is a Slug-induced miRNA that relays the pro-metastatic effects of Slug by targeting TFAP2C. Our findings add new components to the Slug-mediated regulatory network in lung cancer, and suggest that Slug, miR-137, and TFAP2C may be useful prognostic markers in lung adenocarcinoma.