miR-518b is down-regulated, and involved in cell proliferation and invasion by targeting Rap1b in esophageal squamous cell carcinoma

Novel Pt(IV) complexes containing salvigenin ligand reverse cisplatin-induced resistance by inhibiting Rap1b-mediated cancer cell stemness in esophageal squamous cell carcinoma treatments

Esophageal squamous cell carcinoma (ESCC) is a malignant tumor that is highly susceptible to metastasis, recurrence and resistance, and few therapeutic targets have been identified and proven effective. Herein, we demonstrated for the first time that Rap1b can positively regulate ESCC cell stemness, as well as designed and synthesized a novel class of Pt(IV) complexes that can effectively inhibit Raplb. In vitro biological studies showed that complex-1 exhibited stronger cytotoxicity than cisplatin and oxaliplatin against a variety of ESCC cells, and effectively reversed cisplatin-induced resistance of TE6 cells by increasing cellular accumulation of platinum and inhibiting cancer cell stemness. Significantly, complex-1 also exhibited strong ability to reversal cisplatin-induced cancer cell resistance and inhibit tumor growth in TE6/cDDP xenograft mice models, with a tumor growth inhibition rate of 73.3 % at 13 mg/kg and did not show significant systemic toxicity. Overall, Rap1b is a promising target to be developed as an effective treatment for ESCC. Complex-1, as the first Pt(IV) complex that can strongly inhibit Rap1b, is also worthy of further in-depth study.

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

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

The Role of Cluster C19MC in Pre-Eclampsia Development

Pre-eclampsia is a placenta-related complication occurring in 2-10% of all pregnancies. miRNAs are a group of non-coding RNAs regulating gene expression. There is evidence that C19MC miRNAs are involved in the development of the placenta. Deregulation of chromosome 19 microRNA cluster (C19MC) miRNAs expression leads to impaired cell differentiation, abnormal trophoblast invasion and pathological angiogenesis, which can lead to the development of pre-eclampsia. Information was obtained through a review of articles available in PubMed Medline. Articles on the role of the C19MC miRNA in the development of pre-eclampsia published in 2009-2022 were analyzed. This review article summarizes the current data on the role of the C19MC miRNA in the development of pre-eclampsia. They indicate a significant increase in the expression of most C19MC miRNAs in placental tissue and a high level of circulating fractions in serum and plasma, both in the first and/or third trimester in women with PE. Only for miR-525-5p, low levels of plasma expression were noted in the first trimester, and in the placenta in the third trimester. The search for molecular factors indicating the development of pre-eclampsia before the onset of clinical symptoms seems to be a promising diagnostic route. Identifying women at risk of developing pre-eclampsia at the pre-symptomatic stage would avoid serious complications in both mothers and fetuses. We believe that miRNAs belonging to cluster C19MC could be promising biomarkers of pre-eclampsia development.

The E6 Oncoprotein of HPV16 AA-c Variant Regulates Cell Migration through the MINCR/miR-28-5p/RAP1B Axis

The E6 oncoprotein of HPV16 variants differentially alters the transcription of the genes involved in migration and non-coding RNAs such as lncRNAs. The role of the lncRNA MINCR in cervical cancer and its relationship with variants of oncogenic HPV remain unknown. Therefore, the objective of this study was to analyze the effect of the E6 oncoprotein of the AA-c variant of HPV16 in cell migration through the MINCR/miR-28-5p/RAP1B axis. To explore the functional role of MINCR in CC, we used an in vitro model of C33-A cells with exogenous expression of the E6 oncoprotein of the AA-c variant of HPV16. Interfering RNAs performed MINCR silencing, and the expression of miR-28-5p and RAP1B mRNA was analyzed by RT-qPCR. We found that C33-A/AA-c cells expressed MINCR 8-fold higher compared to the control cells. There is an inverse correlation between the expression of miR-28-5p and RAP1B in C33-A/AA-c cells. Our results suggest that MINCR might regulate the expression of RAP1B through the inhibition of miR-28-5p in CC cells expressing the E6 oncoprotein of HPV16 AA-c. We report, for the first time, that the MINCR/miR-28-5p/RAP1B axis positively regulates cell migration in CC-derived cells that express the E6 oncoprotein of the AA-c variant of HPV16.

MiR-323a-3p acts as a tumor suppressor by suppressing FMR1 and predicts better esophageal squamous cell carcinoma outcome

Background

Esophageal squamous cell carcinoma (ESCC) has unfavorable outcomes with the highest incidence seen in China. Accordingly, exploring effective molecular biomarkers is of great value. MicroRNAs (miRNAs) are posttranscriptional regulators of gene expression and modulate numerous biological processes in tumors. Our study aimed to identify prognostic miRNAs and investigate their role in ESCC.

Methods

Prognosis-related plasma miRNAs were detected by miRNA microarray and qRT-PCR. Functional assays and molecular mechanism studies were used to investigate the role of miRNA in ESCC.

Results

Over-expression of miR-323a-3p was associated with a favorable prognosis. MiR-323a-3p negatively regulated proliferation, migration, and invasion. Through biological predictions, the fragile X mental retardation 1 (FMR1) was found to be a potential target of miR-323a-3p. Further investigation revealed that miR-323a-3p directly targeted and suppressed FMR1. MiR-323a-3p and FMR1 mRNA, as well as miR-323a-3p and the FMR1-encoded protein FMRP, showed negative correlations. Luciferase activity of FMR1-3′-UTR, but not mutant counterparts, was decreased by mimic compared with that of the control. The compromised cell proliferation, migration, and invasion induced by transfection with miR-323a-3p mimic were rescued by transfection with a FMR1 expression plasmid. Tumors induced by miR-323a-3p overexpressed ESCC cells grew significantly slower in vivo and resulted in smaller tumor masses. Metastatic lung colonization was also inhibited by miR-323a-3p overexpression.

Conclusions

MiR-323a-3p was significantly associated with survival and acted as a tumor suppressor by inhibiting proliferation, migration, and invasion via the regulation of FMR1. MiR-323a-3p is a promising biomarker and may be a potential therapeutic target.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-022-02541-x.

Long Non-Coding RNAs H19 and HOTAIR Implicated in Intervertebral Disc Degeneration

Objective: Intervertebral disc degeneration (IDD) is the major cause of low back pain. We aimed to identify the key genes for IDD pathogenesis.

Methods: An integrated analysis of microarray datasets of IDD archived in public Gene Expression Omnibus was performed. Bioinformatics analyses including identification of differentially expressed mRNAs/microRNAs/long non-coding RNAs (DEMs/DEMis/DELs), pathway enrichment, and competitive endogenous RNA (ceRNA) network construction were performed to give insights into the potential functions of differentially expressed genes (DEGs, including DEMs, DEMis, and DELs). The diagnostic value of DEMis in distinguishing IDD from normal controls was evaluated through receiver operating characteristic (ROC) analysis.

Results: DEGs were identified in IDD, including H19 and HOTAIR. In the DEMis–DEMs network of IDD, miR-1291, miR-4270, and miR-320b had high connectivity with targeted DEMs. Cell death biological processes and the JAK–STAT pathway were significantly enriched from targeted DEMs. The area under the curve (AUC) of 10 DEMs including miR-1273e, miR-623, miR-518b, and miR-1291 in ROC analysis was more than 0.8, which indicated that those 10 DEMs had diagnostic value in distinguishing IDD from normal individuals.

Conclusions: DELs H19 and HOTAIR were related to IDD pathogenesis. Cell death biological processes and the JAK–STAT pathway might play key roles in IDD development.

Roles of MicroRNAs in Esophageal Squamous Cell Carcinoma Pathogenesis

MicroRNAs (miRNAs) are 20-22 nucleotides long single-stranded noncoding RNAs. They regulate gene expression posttranscriptionally by base pairing with the complementary sequences in the 3'-untranslated region of their targeted mRNA. Aberrant expression of miRNAs leads to alterations in the expression of oncogenes and tumor suppressors, thereby affecting cellular growth, proliferation, apoptosis, motility, and invasion capacity of gastrointestinal cells, including cells of esophageal squamous cell carcinoma (ESCC). Thus, alterations in miRNAs expression associated with the pathogenesis and progression of ESCC. In addition, expression profiles of miRNAs correlated with various clinicopathological factors, including pathological stages, histological differentiation, invasion, metastasis of cancer, as well as survival rates and therapy response of patients with ESCC. Consequently, expression profiles of miRNAs could be useful as diagnostic, prognostic, and prediction biomarkers in ESCC. Herein, we describe the quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) and microarray methods for detection and quantitate miRNAs in ESCC. In addition, we summarize the roles of miRNAs in ESCC pathogenesis, progression, and prognosis.

Zinc Gluconate Induces Potentially Cancer Chemopreventive Activity in Barrett's Esophagus: A Phase 1 Pilot Study

BACKGROUND

Chemopreventive effects of zinc for esophageal cancer have been well documented in animal models. This prospective study explores if a similar, potentially chemopreventive action can be seen in Barrett's esophagus (BE) in humans.

AIMS

To determine if molecular evidence can be obtained potentially indicating zinc's chemopreventive action in Barrett's metaplasia.

METHODS

Patients with a prior BE diagnosis were placed on oral zinc gluconate (14 days of 26.4 mg zinc BID) or a sodium gluconate placebo, prior to their surveillance endoscopy procedure. Biopsies of Barrett's mucosa were then obtained for miRNA and mRNA microarrays, or protein analyses.

RESULTS

Zinc-induced mRNA changes were observed for a large number of transcripts. These included downregulation of transcripts encoding proinflammatory proteins (IL32, IL1β, IL15, IL7R, IL2R, IL15R, IL3R), upregulation of anti-inflammatory mediators (IL1RA), downregulation of transcripts mediating epithelial-to-mesenchymal transition (EMT) (LIF, MYB, LYN, MTA1, SRC, SNAIL1, and TWIST1), and upregulation of transcripts that oppose EMT (BMP7, MTSS1, TRIB3, GRHL1). miRNA arrays showed significant upregulation of seven miRs with tumor suppressor activity (-125b-5P, -132-3P, -548z, -551a, -504, -518, and -34a-5P). Of proteins analyzed by Western blot, increased expression of the pro-apoptotic protein, BAX, and the tight junctional protein, CLAUDIN-7, along with decreased expression of BCL-2 and VEGF-R2 were noteworthy.

CONCLUSIONS

When these mRNA, miRNA, and protein molecular data are considered collectively, a cancer chemopreventive action by zinc in Barrett's metaplasia may be possible for this precancerous esophageal tissue. These results and the extensive prior animal model studies argue for a future prospective clinical trial for this safe, easily-administered, and inexpensive micronutrient, that could determine if a chemopreventive action truly exists.

Bioinformatics-Based Identification of a circRNA-miRNA-mRNA Axis in Esophageal Squamous Cell Carcinomas

Background

Esophageal squamous cell carcinoma (ESCC) has a poor prognosis due to the lack of early disease symptoms. Using bioinformatics tools, this study aimed to discover differentially expressed nonprotein-coding RNAs and genes with potential prognostic relevance in ESCC.

Methods

Two microRNAs (miRNAs) and one circular RNA (circRNA) microarray datasets were downloaded from the Gene Expression Omnibus (GEO) database. Differential expression of miRNAs (DEMs) and circRNAs (DECs) was, respectively, identified in ESCC tissue and compared to adjacent healthy tissue. Further analysis was performed using the miRNA microarray datasets, where miRTarBase was used to predict which messenger RNAs (mRNAs) was present. This was followed by protein-protein interaction (PPI) network, Kyoto Encyclopedia of Genes and Genomes (KEGG), and Gene Ontology (GO) analyses. Moreover, cytoHubba and UALCAN were used to predict the important nodes and perform patient survival analysis, respectively. The miRNA-associated circRNAs were predicted using the ENCORI website. The interaction between DECs and the predicted circRNAs was also determined. A circRNA-miRNA-mRNA axis was constructed.

Results

Associated with RAP1B and circ_0052867, two miRNAs (miR-133b and miR-139-5p) were identified as being differentially expressed and downregulated across the two datasets. Finally, the circ_0052867/miR-139-5p/RAP1B regulatory axis was established.

Conclusion

This study provides support for the possible mechanisms of disease progression in ESCC.

Identification of Acute Myeloid Leukemia Bone Marrow Circulating MicroRNAs

BACKGROUND

In addition to their roles in different biological processes, microRNAs in the tumor microenvironment appear to be potential diagnostic and prognostic biomarkers for various malignant diseases, including acute myeloid leukemia (AML). To date, no screening of circulating miRNAs has been carried out in the bone marrow compartment of AML. Accordingly, we investigated the circulating miRNA profile in AML bone marrow at diagnosis (AMLD) and first complete remission post treatment (AMLPT) in comparison to healthy donors (HD).

METHODS

Circulating miRNAs were isolated from AML bone marrow aspirations, and a low-density TaqMan miRNA array was performed to identify deregulated miRNAs followed by quantitative RT-PCR to validate the results. Bioinformatic analysis was conducted to evaluate the diagnostic and prognostic accuracy of the highly and significantly identified deregulated miRNA(s) as potential candidate biomarker(s).

RESULTS

We found several deregulated miRNAs between the AMLD vs. HD vs. AMLPT groups, which were involved in tumor progression and immune suppression pathways. We also identified significant diagnostic and prognostic signatures with the ability to predict AML patient treatment response.

CONCLUSIONS

This study provides a possible role of enriched circulating bone marrow miRNAs in the initiation and progression of AML and highlights new markers for prognosis and treatment monitoring.

The Role of Ras-Associated Protein 1 (Rap1) in Cancer: Bad Actor or Good Player?

Metastasis is known as the most life-threatening event in cancer patients. In principle, the immune system can prevent tumor development. However, dysfunctional T cells may fail to eliminate the tumor cells effectively and provide additional survival advantages for tumor proliferation and metastasis. Constitutive activation of Ras-associated protein1 (Rap1) has not only led to T cell anergy, but also inhibited autophagy and supported cancer progression through various oncogenic events. Inhibition of Rap1 activity with its negative regulator, Rap1GAP, impairs tumor progression. However, active Rap1 reduces tumor invasion in some cancers, indicating that the pleiotropic effects of Rap1 signaling in cancers could be cancer-specific. All in all, targeting Rap1 signaling and its regulators could potentially control carcinogenesis, metastasis, chemoresistance and immune evasion. Rap1GAP could be a promising therapeutic target in combating cancer.

MicroRNA-101 suppresses colorectal cancer progression by negative regulation of Rap1b

Colorectal cancer (CRC) is the fourth most lethal malignancy and is the second most common cause of cancer-associated mortality worldwide. The development of high-throughput sequencing has enabled the identification of potential biomarkers for the diagnosis and treatment of various types of cancer. Although microRNA-101 (miR-101) has been demonstrated to be a potential biomarker of CRC, its detailed mechanisms remain to be fully discovered. In the present study, overall survival analysis was applied to determine the association between miR-101 and CRC prognosis. Reverse transcription-quantitative PCR (RT-qPCR) was used to examine gene expression levels in tissues and cells. Cell proliferative and apoptotic activities were determined by MTT and flow cytometry assays, respectively. Wound healing and Transwell assays were used to examine CRC cell migration and invasion, respectively. In the present study, RT-qPCR analysis indicated that miR-101 was significantly downregulated in CRC tissues and cells. However, clinical data collected from The Cancer Genome Atlas revealed no significant association between the expression levels of miR-101 and the prognosis of CRC. Additionally, miR-101 inhibited the progression of CRC by directly binding to the 3′-untranslated region of Ras-related protein Rap1b (Rap1b). This was associated with downregulation of Rap1b expression. Furthermore, the overexpression of Rap1b promoted miR-101 mimic-attenuated CRC cell progression. The present study demonstrated that miR-101 may be involved in the repression of the CRC progression by forming a negative feedback loop with Rap1b. The findings revealed the interaction between miR-101 and Rap1b during the progression of CRC, which could aid the development of therapeutic strategies.

Micro RNA-363 inhibits esophageal squamous cell carcinoma progression by directly targeting sperm-associated antigen 5

OBJECTIVE

Micro RNA (miR)-363 has many important biological functions in cancers, but its roles in esophageal squamous cell carcinoma (ESCC) remain unclear.

METHODS

We used reverse transcription PCR to quantify the expression of miR-363 in 80 ESCC tissues and analyzed its relationship with clinicopathological factors and overall survival. The effects of miR-363 on cell proliferation, apoptosis, and invasion were detected using the MTT assay, flow cytometry, and Transwell invasion assays, respectively. Further, we investigated the post-transcriptional regulation of sperm-associated antigen 5 (SPAG5) expression by miR-363 using luciferase reporter assays. Finally, the effects of SPAG5 on miR-363 were studied by SPAG5 overexpression.

RESULTS

miR-363 expression was decreased in both ESCC specimens and cell lines, compared with controls, and correlated with lymph node metastasis and tumor differentiation. Low miR-363 expression was identified as an independent prognostic factor for ESCC. miR-363 overexpression decreased ESCC cell proliferation and invasion and increased apoptosis, while the opposite was seen after miR-363 inhibition. Moreover, SPAG5 was identified as a direct target of miR-363, and the reintroduction of SPAG5 restored miR-363-induced effects.

CONCLUSIONS

miR-363 acts as a tumor suppressor by post-transcriptionally regulating SPAG5 expression, suggesting its potential as a diagnostic biomarker and therapeutic target for ESCC.

Overexpression of miR-518b in non-small cell lung cancer serves as a biomarker and facilitates tumor cell proliferation, migration and invasion

Several microRNAs (miRNA/miR) have been reported to serve critical roles in tumorigenesis. The present study aimed to investigate miR-518b expression in non-small cell lung cancer (NSCLC), and determine its clinical significance and biological function in this malignancy. Reverse transcription-quantitative PCR was performed to assess miR-518b expression in NSCLC. The diagnostic value of miR-518b was determined via a receiver operating characteristic curve, while its prognostic value was assessed using the Kaplan-Meier method. Gain- and loss-of-function experiments were performed to determine the functional role of miR-518b in NSCLC progression. The results demonstrated that miR-518b expression was upregulated in NSCLC serum, tissues and cell lines compared with the corresponding normal controls. Furthermore, high miR-518b expression was significantly associated with larger tumor size, lymph node metastasis and advanced TNM stage, as well as poor overall survival in patients with NSCLC. Serum miR-518b expression was identified as a candidate diagnostic biomarker for NSCLC, with sensitivity of 88.1% and specificity of 81.7%. Furthermore, the cell experiments indicated that NSCLC cell proliferation, migration and invasion were enhanced following overexpression of miR-518b; however, these effects were reversed following miR-518b knockdown. Taken together, the results of the present study suggest that elevated miR-518b expression in NSCLC serves a potential oncogenic role by facilitating tumor cell proliferation, migration and invasion, and thus may serve as a candidate diagnostic and prognostic biomarker.

miR-338-5p inhibits cell proliferation, colony formation, migration and cisplatin resistance in esophageal squamous cancer cells by targeting FERMT2

Esophageal cancer is one of the leading causes of cancer death in the male population of Eastern Asia. In addition, esophageal squamous cell carcinoma (ESCC) is the major type of esophageal cancer among the world. Owing to the poor overall 5-year survival rate, novel effective treatment strategies are needed. MicroRNAs are important gene regulators that are dysregulated in many cancer types. In our previous study, we applied next-generation sequencing to demonstrate that miR-338-5p was downregulated in the tumor tissue of patients with versus without recurrence. In this study, we further studied the roles of miR-338-5p in ESCC. The expression of endogenous miR-338-5p was at lower levels in ESCC cells compared with normal cells. Functional assays showed that miR-338-5p reduced cell proliferation, colony formation, migration and cisplatin resistance in an ESCC cell line, CE-81T. Potential target genes of miR-338-5p were identified by microarray and prediction tools, and 31 genes were selected. Among these, Fermitin family homolog 2 (FERMT2) plays an oncogenic role in ESCC, so it was chosen for further study. Luciferase assays showed the direct binding between miR-338-5p and the 3' untranslated region of FERMT2. Silencing of FERMT2 inhibited cell proliferation, colony formation, migration and cisplatin resistance. Pathway analysis revealed that the integrin-linked protein kinase signaling pathway, in which FERMT2 participates, was significantly affected by a miR-338-5p mimic. Our results suggest that miR-338-5p may play an antioncogenic role in ESCC via repressing FERMT2.

CTCF-induced upregulation of HOXA11-AS facilitates cell proliferation and migration by targeting miR-518b/ACTN4 axis in prostate cancer

BACKGROUND

Testified as crucial participators in different types of human malignancies, long noncoding RNAs (lncRNAs) have been revealed to exert a significant effect on the complicated courses of tumor progression. Although existing literatures have revealed the oncogenic role of lncRNA homeobox A11 antisense RNA (HOXA11-AS) in multiple cancers, the underlying role of HOXA11-AS in prostate cancer (PCa) and its potential molecular mechanism remains poorly understood.

AIM

To decipher the molecular performance of HOXA11-AS in PCa.

METHODS

The expression of HOXA11-AS, miR-518b and actinin alpha 4 (ACTN4) was detected by a real-time quantitative polymerase chain reaction. Colony formation, EdU, flow cytometry, wound healing, and transwell assays were utilized to explore the biological role of HOXA11-AS in PCa. The interaction between RNAs (CCCTC-binding factor [CTCF], HOXA11-AS, miR-518b, and ACTN4) was tested via chromatin immunoprecipitation, luciferase reporter and RNA immunoprecipitation assays.

RESULTS

HOXA11-AS in PCa cells was expressed at high levels. Silenced HOXA11-AS in PCa cells could lead to a significant elevation in the abilities of cell proliferation and migration whereas a remarkable declination in cell apoptosis capability. Subsequent molecular mechanism assays confirmed that HOXA11-AS bound with miR-518b and negatively regulates miR-518b expression. Besides, HOXA11-AS could regulate the expression of ACTN4 by sponging miR-518b. Moreover, rescued-function assays revealed that miR-518b inhibition or ACTN4 upregulation reversed the repressive effect of HOXA11-AS knockdown on PCa progression. Furthermore, CTCF was validated to activate HOXA11-AS transcription in PCa cells.

CONCLUSIONS

CTCF-induced upregulation of HOXA11-AS facilitates PCa progression via miR-518b/ACTN4 axis, providing a new target for PCa treatment.

Role of miR-337-3p and its target Rap1A in modulating proliferation, invasion, migration and apoptosis of cervical cancer cells

OBJECTIVE

To investigate the role of miR-337-3p targeting Rap1A in modulating proliferation, invasion, migration and apoptosis of cervical cancer cells.

METHODS

The expression levels of miR-337-3p and Rap1A in cervical cancer tissues and normal tissues were evaluated through quantitative Real-time PCR (qRT-PCR) and Western blotting; and correlations of miR-337-3p with clinicopathological characteristics and prognosis of patients were also analyzed. Besides, human cervical cancer cell line HeLa cells were randomly divided into five groups (Mock, NC, miR-337-3p mimic, Rap1A, and miR-337-3p mimic + Rap1A groups). CCK-8 assay was utilized to measure cell proliferation, flow cytometry to evaluate cell apoptosis, and wound-healing and Transwell assays to detect cell migration and invasion.

RESULTS

Cervical cancer tissues presented a significant decrease in miR-337-3p and a remarkable increase in Rap1A protein. Besides, the expression levels of miR-337-3p and Rap1A were closely related to the major clinicopathological characteristics of cervical cancer; and patients with high-miR-337-3p-expression had the higher 5-year survival rate (all p< 0.05). When compared to Mock group, cells in miR-337-3p mimic group were suppressed in proliferation, migration, and invasion, but significantly promoted in apoptosis; meanwhile, cells in the Rap1A group showed changes in a completely opposite trend (all p< 0.05). Moreover, Rap1A can reverse the effect of miR-337-3p mimic on cell proliferation, invasion, migration and apoptosis (all p< 0.05).

CONCLUSION

MiR-337-3p was discovered to be decreased in cervical cancer, and miR-337-3p up-regulation may inhibit the proliferation, migration and invasion and promote the apoptosis of cervical cancer cells via down-regulating Rap1A.

Fentanyl inhibits proliferation and invasion via enhancing miR-302b expression in esophageal squamous cell carcinoma

Fentanyl is one of the most commonly used intravenous anesthetic agents during cancer resection surgery, but the effect of fentanyl on esophageal squamous cell carcinoma (ESCC) remains unclear. The aim of the present study was to investigate the involvement of microRNA 302b (miR-302b) in the anti-proliferation and anti-invasion effects of fentanyl in ESCC. In the present study, the effects of fentanyl on cell proliferation, apoptosis and invasion were detected using MTT assays, flow cytometry and Transwell assays in ESCC Eca109 and TE1 cell lines. Subsequently, expression of miR-302b was determined using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). RT-qPCR and western blot analysis were performed in order to evaluate the expression of ErbB4, a target of miR-302b. Furthermore, anti-miR were used to inhibit miR-302b in fentanyl-treated ESCC cells in order to evaluate the role of miR-302b in the effect of fentanyl on malignant behaviors. Fentanyl inhibited the proliferation of Eca109 and TE1 cells in a dose- and time-dependent manner. Following exposure to fentanyl for 48 h, Eca109 and TE1 cells exhibited increased apoptosis and decreased invasion. Furthermore, fentanyl upregulated miR-302b expression, but downregulated ErbB4 expression. Finally, loss of miR-302b using the anti-miR technique reversed the effect of fentanyl on cell proliferation, apoptosis and invasion in the two ESCC cell lines. Taken together, the results of the present study indicated that fentanyl inhibits the proliferation and invasion of ESCC cells through upregulation of miR-302b.

TRIM24 promotes hepatocellular carcinoma progression via AMPK signaling

Hepatocellular carcinoma (HCC) is one of the most common cancers diagnosed worldwide. However, the mechanism underlying HCC pathogenesis remains unknown. In the present study, TRIM24 was found increased in human HCC clinical samples and positively correlated with HCC tumor grade. Furthermore, TRIM24 knockdown inhibits proliferation and migration in a human HCC cell line in vitro while also inhibiting tumor growth in vivo. Mechanistically, TRIM24 appears to promote liver tumor development via AMPK signaling as AMPK knockdown alleviated the in vitro and in vivo effects of TRIM24 knockdown in a human HCC cell line. Taken together, these data enhance our understanding of HCC development in addition to highlighting TRIM24-regulated AMPK signaling as a potential therapeutic target for HCC treatment.

Ras and Rap1: A tale of two GTPases

Ras oncoproteins play pivotal roles in both the development and maintenance of many tumor types. Unfortunately, these proteins are difficult to directly target using traditional pharmacological strategies, in part due to their lack of obvious binding pockets or allosteric sites. This obstacle has driven a considerable amount of research into pursuing alternative ways to effectively inhibit Ras, examples of which include inducing mislocalization to prevent Ras maturation and inactivating downstream proteins in Ras-driven signaling pathways. Ras proteins are archetypes of a superfamily of small GTPases that play specific roles in the regulation of many cellular processes, including vesicle trafficking, nuclear transport, cytoskeletal rearrangement, and cell cycle progression. Several other superfamily members have also been linked to the control of normal and cancer cell growth and survival. For example, Rap1 has high sequence similarity to Ras, has overlapping binding partners, and has been demonstrated to both oppose and mimic Ras-driven cancer phenotypes. Rap1 plays an important role in cell adhesion and integrin function in a variety of cell types. Mechanistically, Ras and Rap1 cooperate to initiate and sustain ERK signaling, which is activated in many malignancies and is the target of successful therapeutics. Here we review the role activated Rap1 in ERK signaling and other downstream pathways to promote invasion and cell migration and metastasis in various cancer types.

miR-28-5p acts as a tumor suppressor in renal cell carcinoma for multiple antitumor effects by targeting RAP1B

The incidence and mortality rate of renal cell carcinoma (RCC) have been significantly increasing; however, the mechanisms involved in RCC development and progression are unclear. In this study, we found that miR-28-5p was decreased in RCC tumor specimens and several renal carcinoma cell lines. By using a combination of luciferase reporter assays and western blotting, we identified RAP1B, a Ras-related small GTP-binding oncoprotein implicated in a variety of tumors, as a direct target of miR-28-5p in RCC. The RAP1B protein level was increased in RCC tumor specimens and renal carcinoma cell lines, and this was inversely correlated with miR-28-5p expression. In vitro gain-of-function and loss-of-function studies in human renal carcinoma cell lines, demonstrated that miR-28-5p suppressed cell proliferation and migration by directly inhibiting RAP1B, and this effect was reversed by co-transfection with RAP1B. In addition, the stable overexpression of miR-28-5p inhibited tumor cell proliferation in vivo. This newly identified miR-28-5p/RAP1B axis provides a novel mechanism for the pathogenesis of RCC, and molecules in this axis may serve as potential biomarkers and therapeutic targets for RCC.

MicroRNAs in esophageal squamous cell carcinoma: Potential biomarkers and therapeutic targets

Esophageal cancer is a common cause of cancer-related deaths worldwide. Squamous cell carcinoma (SCC) is the major histological type of esophageal cancer in developing countries including China, and the prognosis is very poor. Many microRNAs are involved in several important biological and pathologic processes, and promote tumorigenesis. To better understand the prognostic and therapeutic roles of microRNAs in ESCC, we reviewed the diagnosis and prognosis associated oncogenic microRNAs (e.g. miR-21 and miR-17-92 cluster) and tumor suppressor microRNAs (e.g. miR-375, miR-133a and miR-133b), and diagnosis and prognosis associated oncogenic target genes (e.g. PDCD4 and CCND1) and tumor suppressor target genes (e.g. EZH2 and PDK1). We also summarized the prognostic microRNA and target gene pairs (e.g. miR-296 and CCND1, miR214 and EZH2). Taken together, our review highlights the opportunities and challenges for microRNAs in the molecular diagnosis and target therapy of ESCC.

miR-518b Enhances Human Trophoblast Cell Proliferation Through Targeting Rap1b and Activating Ras-MAPK Signal

Preeclampsia is a pregnancy-specific complication defined as newly onset gestational hypertension and proteinuria. Deficiency in placental development is considered as the predominant cause of preeclampsia. Our previous study found that the expression of miR-518b increased significantly in the preeclamptic placentas, indicating the potential participation of this small RNA in the occurrence of preeclampsia. In this study, data analysis using multiple databases predicted Rap1b as a candidate target of miR-518b. An evident decrease in Rap1b expression was observed in preeclamptic placentas when compared with the control placentas, which was negatively correlated with the level of miR-518b. Based on the data of in situ hybridization and immunohistochemistry showing that Rap1b exhibited similar localization with miR-518b in villous cytotrophoblast cells and column trophoblasts, we further explored their function in regulating trophoblast cell proliferation. In HTR8/SVneo cells, exogenous transfection of miR-518b reduced the expression of Rap1b, and dual-luciferase reporter assay validated Rap1b as the direct target of miR-518b. The small RNA could increase the BrdU incorporation and the ratio of cells at S phase, and enhance the phosphorylation of Raf-1 and ERK1/2. Such growth-promoting effect could be efficiently reversed by Rap1b overexpression. The data indicate that miR-518b can promote trophoblast cell proliferation via Rap1b-Ras-MAPK pathway, and the aberrant upregulation of miR-518b in preeclamptic placenta may contribute to the excessive trophoblast proliferation. The study provides new evidence to further understand the etiology of preeclampsia.

Gallic Acid and Gallates in Human Health and Disease: Do Mitochondria Hold the Key to Success?

Gallic acid and gallate esters are widely used as dietary supplements or additives with clinical significances. Over the last few decades, a large number of publications have been reported stating the antioxidative, antiapoptotic, cardioprotective, neuroprotective, and anticancer properties of gallic acid and gallates, and mostly demonstrated their antioxidative or prooxidative properties influencing the reactive oxygen species (ROS) signaling networks. However, very little focus has been paid to clinical trials, and this restricted their use as a prescribed preventative supplement. Since mitochondria are the principal organelles responsible for ROS generation, we reviewed the existing literature of mitochondria-specific effects of gallates including ROS production, respiration, mitochondrial biogenesis, apoptosis, and the physico-chemical parameters affecting the outcome of gallate supplementation to various health scenarios such as cardiovascular diseases, neurodegeneration, hepatic ailments, or cancers. The major signaling pathways and the molecules targeted by gallic acid and its derivatives have also been discussed with emphasis on mitochondria as the target site. This review provides a better understanding of the effect of gallic acid and gallate esters on mitochondrial functions and in designing effective preventative measures against the onset of various diseases.

LncRNA MT1JP functions as a tumor suppressor by interacting with TIAR to modulate the p53 pathway

Accumulating evidence suggests that long noncoding RNAs (lncRNAs) play important roles in transcriptional regulation, whereas the extent to which the lncRNAs also function at the posttranscriptional level is less known. In the present study, we report a lncRNA named MT1JP which acts as a tumor suppressor through a posttranscriptional mechanism. We found that MT1JP is differentially expressed in tumor tissues by analyzing data from a customized microarray applied to 76 pairs of matched normal and cancer tissue samples. By associating with the RNA-binding protein TIAR, MT1JP enhanced the translation of the master transcription factor p53, thereby regulating a series of pathways involving p53, such as the cell cycle, apoptosis and proliferation. When MT1JP was down-regulated, the protein level of p53 declined, which in turn accelerated cell deterioration and tumor formation. Moreover, differential expression of MT1JP in cancerous and normal tissues suggests that it may be a promising prognostic marker and a therapeutic target. Taken together, we identified MT1JP as a critical factor in restraining cell transformation by modulating p53 translation through interactions with TIAR, and this finding is likely to shed new light on future investigations about posttranscriptional or translational effects of lncRNAs during cell transformation.

MicroRNA‑518b functions as a tumor suppressor in glioblastoma by targeting PDGFRB

Glioblastoma (GBM) is the most common and aggressive type of primary human brain tumor in China. Dysregulated microRNA (miRNA/miR) expression has been hypothesized to serve a role in the tumorigenesis and progression of human GBM. To explore the potential mechanisms affecting GBM tumorigenesis, the function of miR-518b in regulating GBM cell proliferation and angiogenesis was examined in vitro by CCK-8 and tube formation assay and in vivo by xenograft assay. The present study demonstrated that the expression of miR-518b was downregulated in GBM tissues and in GBM cell lines (U87 and U251). In addition, the expression levels of miR-518b were highly associated with tumor size, World Health Organization grade and prognosis. Furthermore, overexpression of miR-518b suppressed GBM cell proliferation and angiogenesis, and induced GBM cell apoptosis in vitro and in vivo. Overexpression of miR-518b also inhibited the expression of platelet-derived growth factor receptor β (PDGFRB), and the present study confirmed that the 3′ untranslated region (3′UTR) of PDGFRB was a direct target of miR-518b. In conclusion, to the best of our knowledge, the present study is the first to present evidence suggesting that miR-518b may serve as a potential marker and target in GBM treatment.

MicroRNA-181c inhibits cigarette smoke-induced chronic obstructive pulmonary disease by regulating CCN1 expression

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is an obstinate pulmonary disease, causing irreversible alveoli collapse and increasing the risk for cardiovascular disease. Accumulating evidence has shown that the dysregulation of miRNAs is crucially involved in the pathogenesis and development of COPD. However, the effects and role of microRNA-181c (miR-181c) have not been investigated in a murine model of COPD.

METHODS

miR-181c expression was detected in human lung tissue samples of 34 patients, an in vivo murine model of CS exposure, and primary human bronchial epithelial cells (HBECs) by qRT-PCR. Degeneration of lung tissue, necrosis, infiltration and neutrophil cells were assessed with H&E and flow cytometry. Interleukin (IL)-6 and IL-8 levels were determined by an enzyme-linked immunosorbent assay and qRT-PCR. Luciferase reporter assay and correlation analyses were used to confirm and measure the levels between miR-181c and its target CCN1.

RESULTS

We showed that miR-181c was significantly down-regulated in lung tissues from patients with COPD compared to individuals who had never smoked (p < 0.01). We also observed a down-regulation of miR-181c in HBECs and a mouse model after cigarette smoke (CS) exposure. Functional assays demonstrated that miR-181c over-expression decreased the inflammatory response, neutrophil infiltration, reactive oxygen species (ROS) generation, and inflammatory cytokines induced by CS, while its down-regulation produced the opposite effects. Subsequent investigation found that CCN1 was a direct target of miR-181c. CCN1 expression was increased in lung tissues of COPD patients, and was negatively correlated with miR-181c expression in human COPD samples (p < 0.01).

CONCLUSIONS

Taken together, our data suggest the critical roles of miR-181c and its target CCN1 in COPD development, and provide potential therapeutic targets for COPD treatment.

First trimester screening of circulating C19MC microRNAs and the evaluation of their potential to predict the onset of preeclampsia and IUGR

Objectives

A nested case control study of a longitudinal cohort comparing pregnant women enrolled at 10 to 13 gestational weeks was carried out to evaluate risk assessment for preeclampsia and IUGR based on circulating placental specific C19MC microRNAs in early pregnancy.

Methods

The expression of placental specific C19MC microRNAs (miR-516b-5p, miR-517-5p, miR-518b, miR-520a-5p, miR-520h, and miR-525-5p) was determined in plasma samples from pregnancies that subsequently developed preeclampsia (n = 21), IUGR (n = 18), and 58 normal pregnancies using real-time PCR and comparative Ct method relative to synthetic Caenorhabditis elegans microRNA (cel-miR-39).

Results

Circulating C19MC microRNAs were up-regulated (miR-517-5p, p = 0.005; miR-518b, p = 0.013; miR-520h, p = 0.021) or showed a trend toward up-regulation in patients destined to develop preeclampsia (miR-520a-5p, p = 0.067; miR-525-5p, p = 0.073). MiR-517-5p had the best predictive performance for preeclampsia with a sensitivity of 42.9%, a specificity of 86.2%, a PPV of 52.9% and a NPV of 80.6%. The combination of all examined circulating C19MC microRNAs had no advantage over using only the miR-517-5p biomarker to predict the occurrence of preeclampsia (a sensitivity of 20.6%, a specificity of 90.8%, a PPV of 44.8%, and a NPV of 76.0%).

Conclusions

Up-regulation of miR-517-5p, miR-518b and miR-520h was associated with a risk of later development of preeclampsia. First trimester screening of extracellular miR-517-5p identified a proportion of women with subsequent preeclampsia. No circulating C19MC microRNA biomarkers were identified that could predict later occurrence of IUGR.

RAP1B, a DVL2 binding protein, activates Wnt/beta-catenin signaling in esophageal squamous cell carcinoma

RAP1B is a small GTPase, which regulates multiple cellular processes. Up-regulation of RAP1B has been observed in several cancer types. Although previous study has shown that miR-518 inhibited the proliferation and invasion of esophageal squamous cell carcinoma (ESCC) cells possibly by targeting RAP1B, the expression pattern and the functions of RAP1B in ESCC are not fully understood. Here, we have fund that the expression of RAP1B was up-regulated in ESCC clinical samples. Gain-of-function and loss-of-function assays demonstrated that RAP1B promoted the growth, migration and metastasis of the ESCC cells. Moreover, the mechanism study showed that RAP1B interacted with DVL2, an important upstream regulator for beta-catenin/TCF signaling, and activated beta-catenin/TCF signaling. Taken together, our study demonstrated the oncogenic roles of RAP1B in ESCC, and suggested that RAP1B might be a therapeutic target.

The role of microRNA in esophageal squamous cell carcinoma

MicroRNAs (miRNA) are 22-nucleotide non-coding RNAs that post-transcriptionally regulate gene expression by base pairing to partially complementary sequences in the 3'-untranslated region of their target messenger RNA. Altered miRNA expression also changes the expression of oncogenes and tumor suppressors, affecting the proliferation, apoptosis, motility and invasibility of gastrointestinal cancer cells, including the cells of esophageal squamous cell carcinoma (ESCC). It has been suggested that various miRNA expression profiles may provide useful biomarkers and therapeutic targets, but to date few studies have been published on the role of miRNA in ESCC. In this review we summarize the identification and characterization of miRNAs involved in ESCC and discuss their potential as biomarkers and therapeutic targets.

miR-1 suppresses the growth of esophageal squamous cell carcinoma in vivo and in vitro through the downregulation of MET, cyclin D1 and CDK4 expression

Several aberrant microRNAs (miRNAs or miRs) have been implicated in esophageal cancer (EC), which is widely prevalent in China. However, their role in EC tumorigenesis has not yet been fully elucidated. In the present study, we determined that miR-1 was downregulated in esophageal squamous cell carcinoma (ESCC) tissues compared with adjacent non-neoplastic tissues using RT-qPCR, and confirmed this using an ESCC cell line. Using a nude mouse xenograft model, we confirmed that the re-expression of miR-1 significantly inhibited ESCC tumor growth. A tetrazolium assay and a trypan blue exclusion assay revealed that miR-1 suppressed ESCC cell proliferation and increased apoptosis, whereas the silencing of miR-1 promoted cell proliferation and decreased apoptosis, suggesting that miR-1 is a novel tumor suppressor. To elucidate the molecular mechanisms of action of miR-1 in ESCC, we investigated putative targets using bioinformatics tools. MET, cyclin D1 and cyclin-dependent kinase 4 (CDK4), which are involved in the hepatocyte growth factor (HGF)/MET signaling pathway, were found to be targets of miR-1. miR-1 expression inversely correlated with MET, cyclin D1 and CDK4 expression in ESCC cells. miR-1 directly targeted MET, cyclin D1 and CDK4, suppressing ESCC cell growth. The newly identified miR-1/MET/cyclin D1/CDK4 axis provides new insight into the molecular mechanisms of ESCC pathogenesis and indicates a novel strategy for the diagnosis and treatment of ESCC.

Mutant p53 inhibits miRNA biogenesis by interfering with the microprocessor complex

Downregulation of microRNAs (miRNAs) is commonly observed in cancers and promotes tumorigenesis suggesting that miRNAs may function as tumor suppressors. However, the mechanism through which miRNAs are regulated in cancer, and the connection between oncogenes and miRNA biogenesis remain poorly understood. The TP53 tumor-suppressor gene is mutated in half of human cancers resulting in an oncogene with gain-of-function activities. Here we demonstrate that mutant p53 (mutp53) oncoproteins modulate the biogenesis of a subset of miRNAs in cancer cells inhibiting their post-transcriptional maturation. Interestingly, among these miRNAs several are also downregulated in human tumors. By confocal, co-immunoprecipitation and RNA-chromatin immunoprecipitation experiments, we show that endogenous mutp53 binds and sequesters RNA helicases p72/82 from the microprocessor complex, interfering with Drosha-pri-miRNAs association. In agreement with this, the overexpression of p72 leads to an increase of mature miRNAs levels. Moreover, functional experiments demonstrate the oncosuppressive role of mutp53-dependent miRNAs (miR-517a, -519a, -218, -105). Our study highlights a previously undescribed mechanism by which mutp53 interferes with Drosha-p72/82 association leading, at least in part, to miRNA deregulation observed in cancer.

Dysregulation of microRNA biogenesis in cancer: the impact of mutant p53 on Drosha complex activity

A widespread decrease of mature microRNAs is often observed in human malignancies giving them potential to act as tumor suppressors. Thus, microRNAs may be potential targets for cancer therapy. The global miRNA deregulation is often the result of defects in the miRNA biogenesis pathway, such as genomic mutation or aberrant expression/localization of enzymes and cofactors responsible of miRNA maturation. Alterations in the miRNA biogenesis machinery impact on the establishment and development of cancer programs. Accumulation of pri-microRNAs and corresponding depletion of mature microRNAs occurs in human cancers compared to normal tissues, strongly indicating an impairment of crucial steps in microRNA biogenesis. In agreement, inhibition of microRNA biogenesis, by depletion of Dicer1 and Drosha, tends to enhance tumorigenesis in vivo. The p53 tumor suppressor gene, TP53, is mutated in half of human tumors resulting in an oncogene with Gain-Of-Function activities. In this review we discuss recent studies that have underlined a role of mutant p53 (mutp53) on the global regulation of miRNA biogenesis in cancer. In particular we describe how a new transcriptionally independent function of mutant p53 in miRNA maturation, through a mechanism by which this oncogene is able to interfere with the Drosha processing machinery, generally inhibits miRNA processing in cancer and consequently impacts on carcinogenesis.

Knockdown of Rap1b Enhances Apoptosis and Autophagy in Gastric Cancer Cells via the PI3K/Akt/mTOR Pathway

Gastric cancer (GC) is the fourth most common malignancy and the second leading cause of cancer mortality around the world. However, the regulatory mechanisms of GC tumorigenesis and cancer cell motility are completely unknown. We investigated the role of a RAS-related protein (Rap1b) in the progression of GC. Our results showed that the expression of Rap1b is aberrantly upregulated in GC tissue samples and human GC cell lines, and the high expression of Rap1b indicated a positive correlation with poor prognosis in patients with GC. Inhibition of endogenous Rap1b dramatically reduced the cell cycle progression but strongly enhanced the apoptosis capacity of human GC cell lines MKN-28 and SGC-7901 cells compared with the control group. Western blotting assay showed that Rap1b inhibition resulted in a significant increase in the ratio of LC3-II to LC3-I, and the levels of p62 protein were decreased in both MKN-28 and SGC-7901 cells. Furthermore, PI3K/Akt/mTOR activation was found to be maintained in a low level in the normal gastric mucosal epithelial cells, while it was significantly upregulated in GC cells, which could be decreased by Rap1b inhibition. The PI3K inhibitor LY294002 was enhanced but activator insulin-like growth factor 1 (IGF-1) blocked the Rap1b silencing-induced enhancement of apoptosis and autophagy in MKN-28 and SGC-7901 cells. In conclusion, we demonstrate that Rap1b expression is aberrantly increased in GC, resulting in the inhibition of autophagy and apoptosis of GC cells by the PI3K/Akt/mTOR pathway. This might provide a new understanding and represent a novel therapeutic target for human GC.

miRNA-mRNA crosstalk in esophageal cancer: From diagnosis to therapy

The asymptomatic nature of esophageal cancer (EC) at early stages results in late clinical presentation leading to poor prognosis and limited success of therapeutic modalities. Efforts to identify diagnostic/prognostic markers have proven to be unsuccessful for translation into clinics. Hence, there is a pressing need for establishment of novel non-invasive biomarker for early diagnosis/better prognosis of EC. Recently, alteration in microRNA (miRNA) expression has emerged as an important hallmark of cancer. This review summarizes the differential expression of miRNAs in EC and addresses how their aberrant expression influences crucial biological processes such as apoptosis, cell proliferation, invasion and metastasis. Additionally, this review highlights the current status of circulating miRNA based diagnostic/prognostic markers. An effort has been made to find a connection between different miRNAs involved in EC and a detailed analysis has been done to screen out micoRNAs involved in prognosis and multidrug resistance. Further, investigation of these miRNAs would not only provide a gene therapy based strategy to prevent/treat cancer but also to reverse multidrug resistance leading to decreased requirement of harmful chemotherapeutic drugs.

MicroRNA-338-3p suppresses tumor growth of esophageal squamous cell carcinoma in vitro and in vivo

Accumulating evidence has shown that microRNAs (miRNAs) are aberrantly expressed in human esophageal squamous cell carcinoma (ESCC) and are crucial in tumorigenesis, among which miR‑338‑3p has been examined to be downregulated in patients with ESCC. However, the role of miR‑338‑3p in ESCC remains to be elucidated. In the present study, the role of miR‑338‑3p on the growth and survival of an ESCC cell line was determined with several in vitro approaches and in nude mouse models. It was determined that miR‑338‑3p expression was frequently downregulated in ESCC tissue compared with corresponding adjacent non‑tumor tissue, and that its expression was significantly correlated with tumor stage and metastasis. Overexpression of miR‑338‑3p in ESCC cells suppressed cell proliferation, colony formation, migration and invasion, and induced cell arrest at the G0/G1 stage and cell apoptosis in vitro. In addition, it was demonstrated that overexpression of miR‑338‑3p significantly suppresses tumor growth of xenograft tumors in mice (P<0.05). These findings revealed that miR‑338‑3p may act as a tumor suppressor in ESCC, and its dysregulation may be involved in the initiation and development of human ESCC. In addition, it was suggested that miR‑338‑3p may be a potential therapeutic agent for treatment of ESCC.

Glucocorticoids mediate induction of microRNA-708 to suppress ovarian cancer metastasis through targeting Rap1B

Glucocorticoids are widely used in conjunction with chemotherapy for ovarian cancer to prevent hypersensitivity reactions. Here we reveal a novel role for glucocorticoids in the inhibition of ovarian cancer metastasis. Glucocorticoid treatments induce the expression of miR-708, leading to the suppression of Rap1B, which result in the reduction of integrin-mediated focal adhesion formation, inhibition of ovarian cancer cell migration/invasion and impaired abdominal metastasis in an orthotopic xenograft mouse model. Restoring Rap1B expression reverts glucocorticoid-miR-708 cascade-mediated suppression of ovarian cancer cell invasion and metastasis. Clinically, low miR-708 and high Rap1B are found in late-state ovarian tumours, as compared with normal, and patients with high miR-708 show significantly better survival. Overall, our findings reveal an opportunity for glucocorticoids and their downstream mediators, miR-708 or Rap1B, as therapeutic modalities against metastatic ovarian epithelial cancer.

Glucocorticoids show promise for the treatment of ovarian cancer. Here the authors show that glucocorticoids transcriptionally induce the tumour suppressor miR-708, which is downregulated in ovarian cancer, especially in late stages and metastatic tumours.

miR-218 suppresses tumor growth and enhances the chemosensitivity of esophageal squamous cell carcinoma to cisplatin

A growing body of evidence suggests that microRNA-218 (miR-218) acts as a tumor suppressor and is involved in tumor progression, development and metastasis and confers sensitivity to certain chemotherapeutic drugs in several types of cancer. However, our knowledge concerning the exact roles played by miR-218 in esophageal squamous cell carcinoma (ESCC) and the underlying molecular mechanisms remain relatively unclear. Thus, the aims of this study were to detect the expression of miR-218 in human ESCC tissues and explore its effects on the biological features and chemosensitivity to cisplatin (CDDP) in an ESCC cell line (Eca109), so as to provide new insights for ESCC treatment. Here, we found increased expression of miR-218 in the ESCC tissues compared with that in the matched non-tumor tissues, and its expression level was correlated with key pathological characteristics including clinical stage, tumor depth and metastasis. We also found that enforced expression of miR-218 significantly decreased cell proliferation, colony formation, migration and invasion, induced cell apoptosis and arrested the cell cycle in the G0/G1 phase, as well as suppressed tumor growth in a nude mouse model. In addition, our results showed that miR-218 mimics increased the sensitivity to the antitumor effect of CDDP in the human Eca109 cells. Importantly, this study also showed that miR-218 regulated the expression of phosphorylated PI3K, AKT and mTOR, which may contribute to suppressed tumor growth of ESCC and enhanced sensitivity of ESCC cells. These findings suggest that miR-218 is a potential therapeutic agent for the treatment of ESCC.

Association study of TGFBR2 and miR-518 gene polymorphisms with age at natural menopause, premature ovarian failure, and early menopause among Chinese Han women

Age at natural menopause (ANM), a highly heritable phenotype, has been identified to be closely associated with major hormone-related diseases, including breast cancer and gynecological cancers. We previously identified an important role for the transforming growth factor, β receptor II (TGFBR2) gene polymorphisms in breast cancer susceptibility among Asian women. Considering the important role of ANM in breast carcinogenesis, we hypothesized that TGFBR2 signals were involved in the formation of natural menopause.In a population-based study of 1844 Chinese women, we evaluated the effect of the genetic polymorphisms of TGFBR2 and miR-518 to determine if they are associated with ANM, premature ovarian failure (POF), and early menopause (EM) risk.No significant differences in the distribution of body mass index, education levels, smoking, drinking, and hypertension were detected between POF and EM cases and controls except for POF cases that were older (P = 0.015) than controls and more likely to have dyslipidemia (P = 0.002). The results showed that miR-518 rs7256241 was significantly associated with ANM. The carriers of minor allele G of rs7256241 have significantly higher ANM than those of the major allele homozygotes TT (β = 0.385, P = 0.035). TGFBR2 rs3773661 was significantly associated with POF, with odds ratio (OR) (95% confidence intervals [CIs]) of 0.66 (0.47-0.94) associated with per minor allele C (P = 0.023). The quartiles of genetic risk score were significantly associated with POF (OR, 1.27; 95% CI, 1.02-1.58; Ptrend = 0.034). Sensitivity analyses confirmed the robustness of these findings and no significant interactions were detected.This study provides evidence to implicate TGFBR2 and miR-518 gene polymorphisms as novel susceptibility factors for ANM, POF, and EM in Asians. Further research on these genetic regions will enhance our understanding of the genetic basis of natural menopause.

Mir-126 inhibits growth of SGC-7901 cells by synergistically targeting the oncogenes PI3KR2 and Crk, and the tumor suppressor PLK2

MicroRNA (miRNA)-126 (miR-126) was reported to be downregulated and to act as a tumor suppressor in cancers of the lung, cervix, bladder and prostate. However, the functions of miR-126 in gastric cancer appear to be diverse and are largely unknown. MiR-126 was reported to act as a tumor suppressor by targeting the Crk gene, or as an oncogene by targeting the SOX2 gene in gastric cancer. We identified that the expression of miR-126 was decreased in gastric cancer cell lines and tissues. PLK2, a tumor suppressor gene, was directly regulated by miR-126 in SGC-7901 cells. Overexpression of miR-126 not only suppressed the growth and clone formation of SGC-7901 cells, but also induced apoptosis in vitro, whereas inhibition of miR-126 slightly promoted SGC-7901 cell proliferation. The cell cycle was not affected by miR-126. Moreover, miR-126 suppressed tumor growth in vivo in a xenograft model. PLK2, PI3KR2 and Crk were regulated by miR-126 in SGC-7901 cells. We infer that the functions of miR-126 in gastric cancer depend on synergistic targeting balance between oncogenes and anti-oncogenes. Our study indicates that miR-126 is a tumor suppressor, which in the future may become a therapeutic target for gastric cancer.

MicroRNA-141 promotes the proliferation of non-small cell lung cancer cells by regulating expression of PHLPP1 and PHLPP2

The dysregulation of microRNAs (miRNAs) is crucially implicated in the development of various cancers. In this study, we explored the biological role of miR-141 in non-small cell lung cancer (NSCLC). miR-141 expression was significantly up-regulated in NSCLC tissues, and its overexpression accelerated NSCLC cell proliferation in vitro and tumor growth in vivo. We subsequently identified the antagonists of PI3K/AKT signaling, PH domain leucine-rich-repeats protein phosphatase 1 (PHLPP1) and PHLPP2, as direct targets of miR-141. Re-introduction of PHLPP1 and PHLPP2 abrogated miR-141-induced proliferation of NSCLC cells. Together, the results of this study suggest that miR-141 and its targets PHLPP1 and PHLPP2 play critical roles in NSCLC tumorigenesis, and provide potential therapeutic targets for NSCLC treatment.

MicroRNAs as oncogenes or tumour suppressors in oesophageal cancer: potential biomarkers and therapeutic targets

MicroRNAs are a class of small, non-coding RNAs that can negatively regulate protein-coding genes, and are associated with almost all known physiological and pathological processes, especially cancer. The number of studies documenting miRNA expression patterns in malignancy continues to expand rapidly, with continuously gained critical information regarding how aberrantly expressed miRNAs may contribute to carcinogenesis. miRNAs can influence cancer pathogenesis, playing a potential role as either oncogenes or tumour suppressors. Recently, several miRNAs have been reported to exert different regulatory functions in oesophageal cancer - the carcinoma typically arising from the epithelial lining of the oesophagus. These miRNAs also have potential clinical applications towards developing biomarkers or targets for possible use in diagnosis or therapy in oesophageal cancer. In this review, we have summarized the two (oncogenic or tumour suppressive) roles of miRNAs here, and their applications as potential biomarkers or therapeutic targets, which may illuminate future treatment for oesophageal cancer.

The expression of miR-21 and miR-375 predict prognosis of esophageal cancer

BACKGROUND

MicroRNA is a class of small, well-conserved, non-coding RNAs, and could play a potential role as diagnostic and prognostic biomarkers of esophageal cancers. We aimed to review comprehensively the evidence of microRNA as prognostic biomarkers in esophageal cancers.

METHODS

Studies were identified by searching PubMed, Embase and Web of Science until November 2013. Descriptive characteristics of studies were described and an additional meta-analysis for specific microRNAs which were studied most frequently was performed. Pooled hazard ratios (HRs) and their corresponding 95% confidence intervals (CIs) were calculated. Fixed model or random model method was chosen depending on the heterogeneity among the studies.

RESULTS

Twenty-two studies including a total of 1946 participants were enrolled after a strict filtering and qualifying process. Among 33 prognostic microRNAs identified for esophageal cancer, miR-21 and miR-375 appeared more frequently. The median study size was 70.5 patients (29-249 patients) and the median HR was 3.305 (IQR=1.615-7.31). For the studies evaluating miR-21's association with overall survival (OS), the pooled HR suggested that high level of miR-21 has a negative impact on OS (HR=1.52[1.17-1.98], P=0.001). As for miR-375, the pooled HR for OS (high/low) was 0.53 (95% CI: 0.39-0.73, P<0.001), indicated that low level of miR-375 has a negative impact on OS. These results indicated that microRNAs show promising associations with prognosis in esophageal cancer. Up-regulation of miR-21 and down-regulation of miR-375 can predict unfavourable prognosis in esophageal cancer.

miR-18b and miR-518b Target FOXN1 during epithelial lineage differentiation in pluripotent cells

MicroRNAs (miRNAs) regulate myriad biological processes; however, their role in cell fate choice is relatively unexplored. Pluripotent NT2/D1 embryonal carcinoma cells differentiate into an epithelial/smooth muscle phenotype when treated with bone morphogenetic protein-2 (BMP-2). To identify miRNAs involved in epithelial cell development, we performed miRNA profiling of NT2/D1 cells treated with BMP-2 at 6, 12, and 24 h, and on days 6 and 10. Integration of the miRNA profiling data with previously obtained gene expression profiling (GEP) data of NT2/D1 cells treated with BMP-2 at the same time points identified miR-18b and miR-518b as the top two miRNAs with the highest number of up-regulated predicted targets with known functions in epithelial lineage development. Silencing of miR-18b and miR-518b in NT2/D1 cells revealed several up-regulated TFs with functions in epithelial lineage development; among these, target prediction programs identified FOXN1 as the only direct target of both miRNAs. FOXN1 has previously been shown to play an important role in keratinocyte differentiation and epithelial cell proliferation. NT2/D1 and H9 human embryonic stem cells with silenced miR-18b and miR-518b showed up-regulation of FOXN1 and the epithelial markers CDH1, EPCAM, KRT19, and KRT7. A 3'UTR luciferase assay confirmed FOXN1 to be a target of the two miRNAs, and up-regulation of FOXN1 in NT2/D1 cells led to the expression of epithelial markers. Overexpression of the two miRNAs in BMP-2-treated NT2/D1 cells led to down-regulation of FOXN1 and epithelial lineage markers. These results show that miR-18b and miR-518b are upstream controllers of FOXN1-directed epithelial lineage development.

MicroRNA-100 regulates SW620 colorectal cancer cell proliferation and invasion by targeting RAP1B

MicroRNAs (miRNAs) have been demonstrated to play important roles in tumorigenesis of human cancer. Fewer studies have explored the roles of miR-100 on human colorectal cancer cell proliferation and invasion. In this study, we utilized real-time PCR to verify whether miR-100 was downregulated in human colorectal cancer tissues compared with matched adjacent normal tissues. Functional studies demonstrated that ectopic expression of miR-100 inhabits cell growth and invasion and induce apoptosis, whereas knockdown of miR-100 yielded the reverse phenotype. Mechanistic studies reveal that miR-100 repressed the activity of a reporter gene fused to the 3'-untranslated region (3'-UTR) of RAP1B, whereas miR-100 silencing upregulated the expression of the reporter gene. Furthermore, we also detected that RAP1B mRNA was inversely expressed with miR-100 in colorectal cancer tissues. These data indicate that the miR-100 plays a tumor suppressor role by regulating colorectal cancer cell growth and invasion phenotype, and could serve as a potential maker for colorectal cancer therapy.

Functional analysis of miR-101-3p and Rap1b involved in hepatitis B virus-related hepatocellular carcinoma pathogenesis

MicroRNA-101(miR-101) has been shown to be down-regulated in hepatocellular carcinoma (HCC). The hepatitis B virus (HBV) is a major risk factor in the development and progression of HCC. However, the correlation between HBV and miR-101 has not yet been fully elucidated. In this study, we reported that HBV could repress miR-101-3p by inhibiting its promoter activity and identified the potential effects of miR-101-3p on some important biological properties of HCC cells by targeting Rap1b. Dual-luciferase reporter assays showed that HBV down-regulated miR-101-3p by inhibiting its promoter activity. Down-regulation of miR-101-3p promoted cell proliferation, migration, and reduced apoptosis, and resulted in up-regulation of Rap1b, while overexpression of miR-101-3p inhibited these processes. Moreover, overexpression of Rap1b was able to reverse the suppressed cell proliferation and migration mediated by miR-101-3p. Our data showed that HBV down-regulated miR-101-3p expression by inhibiting its promoter activity, which resulted in up-regulation of Rap1b, and down-regulation of miR-101-3p or up-regulation of Rap1b promoted proliferation and migration of HCC cells. This provides a new understanding of the mechanism of HBV-related HCC pathogenesis and the potential application of miR-101-3p in cancer therapy.

miR-181 subunits enhance the chemosensitivity of temozolomide by Rap1B-mediated cytoskeleton remodeling in glioblastoma cells

Glioblastoma multiforme (GBM) is the most malignant and frequent brain tumor, with an aggressive growth pattern and poor prognosis despite best treatment modalities. Although chemotherapy with temozolomide (TMZ) may restrain tumor growth for some months, TMZ resistance is also common and accounts for many treatment failures. Research into microRNA's role in GBM has shown that microRNAs play a key regulatory role in the GBM, making it a potential therapeutic target. In this study, we demonstrated that the lower expression of miR-181a/b/c/d subunits contributes to astrocytoma tumorigenesis, and their overexpression could inhibit the invasive proliferation of glioblastoma cells by targeting Rap1B-mediated cytoskeleton remodeling and related molecular (Cdc42, RhoA and N-cadherin) changes, suggesting that miR-181 was a critical regulator and might be an important target for glioblastoma treatment. TMZ as a standard chemotherapeutic agent for GBM inhibited the Rap1B expression and actin cytoskeleton remodeling to exert its cell killing by upregulating miR-181a/b/c/d subunits; conversely, each miR-181a/b/c/d subunit enhanced the chemosensitivity of TMZ in glioblastoma cells.