Up-regulation of miR-455-5p by the TGF-β-SMAD signalling axis promotes the proliferation of oral squamous cancer cells by targeting UBE2B

MiR-455-5p Suppresses the Progression of Prostate Cancer by Targeting CCR5

Accumulated evidence indicates that miR-455-5p functions as tumor suppressor in the progression of various cancers. However, the mechanism through which miR-455-5p influences the tumorigenesis of human prostate cancer (PCa) remains undetermined. In this study, reanalysis of data obtained from the Memorial Sloan Kettering Cancer Center showed that miR-455-5p can be used as biomarker for PCa diagnosis and predictor of poor prognosis. Functional assays indicated that miR-455-5p overexpression could suppress cellular proliferation, inhibit tumor growth, and trigger apoptosis by activating and cleaving caspase 3. We experimentally verified that miR-455-5p negatively regulated the C–C motif chemokine receptor 5 (CCR5). Overall, our data demonstrate that miR-455-5p suppressed PCa cellular proliferation and induced cell apoptosis by downregulating CCR5. Thus, miR-455-5p may be considered a new therapeutic strategy for PCa.

WITHDRAWN: MicroRNA-18a promotes proliferation and metastasis in oral squamous cell carcinoma via targeting KLF4

Ahead of Print article withdrawn by publisher.

Pirin: a potential novel therapeutic target for castration-resistant prostate cancer regulated by miR-455-5p

Androgen deprivation therapy is frequently used to treat prostate cancer (PCa), but resistance can occur, a condition known as castration‐resistant prostate cancer (CRPC). Thus, novel approaches for identification of CRPC are important for designing effective PCa treatments. Analysis of microRNA (miRNA) expression signatures by RNA sequencing showed that both passenger and guide strands of the miR‐455‐duplex (miR‐455‐5p and miR‐455‐3p, respectively) acted as antitumor miRNAs in PCa cells. The involvement of miRNA passenger strands in cancer pathogenesis is a novel concept for miRNA functionality. Based on a large patient cohort in The Cancer Genome Atlas, expression of eight miR‐455‐5p/‐3p target genes (PIR: P = 0.0137, LRP8: P = 0.0495, IGFBP3: P = 0.0172, DMBX1: P = 0.0175, CCDC64: P = 0.0446, TUBB1: P = 0.0149, KIF21B: P = 0.0336, and NFAM1: P = 0.0013) was significantly associated with poor prognosis of PCa patients. Here, we focused on PIR (pirin), a highly conserved member of the cupin superfamily. PIR expression was directly regulated by miR‐455‐5p, and PIR overexpression was detected in hormone‐sensitive prostate cancer (HSPC) surgical specimens and CRPC autopsy specimens. Loss‐of‐function assays using siRNA or an inhibitor (bisamide) showed that downregulation of PIR expression blocked cancer cell migration and invasion. Moreover, the miR‐455‐5p/PIR axis contributed to cancer cell aggressiveness. These results suggest that PIR might be a promising diagnostic marker for HSPC and CRPC. Furthermore, CRPC treatment strategies targeting PIR may be possible in the future. Identification of antitumor miRNAs, including miRNA passenger strands, may contribute to the development of new diagnostic markers and therapeutic strategies for CRPC.

Inhibitory effect of microRNA-455-5p on biological functions of esophageal squamous cell carcinoma Eca109 cells via Rab31

The aim of the present study was to examine microRNA (miRNA or miR)-455-5p expression in esophageal squamous cell carcinoma (ESCC) at the tissue and cellular levels in order to elucidate its biological roles. A total of 60 patients with ESCC were enrolled in the present study and reverse transcription-quantitative polymerase chain reaction was used to measure the expression of miR-455-5p. ESCC Eca109 cells were transfected with miR-NC, miR-455-5p mimics or inhibitor and a Cell Counting Kit-8 assay was used to assess proliferation. To investigate the migration and invasion abilities of Eca109 cells, Transwell and Matrigel assays were performed. Western blotting was employed to measure Rab31 protein expression, while a rescue assay was utilized to study the biological roles of miR-455-5p and Rab31 in Eca109 cells. To determine whether Rab31 is a direct target of miR-455-5p, a dual luciferase reporter assay was performed. The results revealed that miR-455-5p expression was decreased in ESCC tissues and was negatively correlated with metastasis and pathogenesis. In vitro overexpression of miR-455-5p inhibited the proliferation, migration and invasion of ESCC Eca109 cells. Furthermore, miR-455-5p regulated the expression of Rab31 protein in Eca109 cells. Rab31 overexpression promoted the proliferation, migration and invasion of Eca109 cells. Luciferase reporter assay results revealed that miR-455-5p is able to bind with the 3'-untranslated region of Rab31 mRNA to regulate its expression. In summary, the results of the present study suggest that miR-455-5p expression is decreased in ESCC tissues and is miR-455-5p is negatively correlated with lymphatic metastasis and differentiation. As a tumor-suppressor gene, miR-455-5p inhibits the proliferation, migration and invasion of ESCC Eca109 cells by suppressing the expression of Rab31.

Ubiquitin-conjugating enzyme E2 B regulates the ubiquitination of O6-methylguanine-DNA methyltransferase and BCNU sensitivity in human nasopharyngeal carcinoma cells

O⁶-Methylguanine-DNA methyltransferase (MGMT) is a DNA repair enzyme that removes the alkyl groups from the O⁶ position of guanine and is then degraded via ubiquitin-mediated degradation. Previous studies indicated that 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) facilitates the ubiquitination and degradation of MGMT in several types of cancer cells. However, the underlying mechanism of MGMT ubiquitination remains unclear. In this study, we demonstrated for the first time that ubiquitin-conjugating enzyme E2 B (UBE2B) is a novel regulator of MGMT ubiquitination mediated by BCNU in nasopharyngeal carcinoma (NPC) cells. The E3 ubiquitin ligase RAD18, a partner of UBE2B, is also involved in BCNU-mediated MGMT ubiquitination. Overexpression/knockdown of UBE2B enhanced/reduced BCNU-mediated MGMT ubiquitination. Surprisingly, UBE2B knockdown significantly increased BCNU cytotoxicity in NPC cells. Therefore, loss of UBE2B seems to disrupt ubiquitin-mediated degradation of alkylated MGMT. We found that UBE2B knockdown reduced MGMT activity, suggesting that loss of UBE2B leads to the accumulation of deactivated MGMT and suppresses MGMT protein turnover in BCNU-treated cells. These findings indicate that UBE2B modulates sensitivity to BCNU in NPC cells by regulating MGMT ubiquitination.

MiR-876-5p modulates head and neck squamous cell carcinoma metastasis and invasion by targeting vimentin

BACKGROUND

Local or distant metastasis remains the main course of death in head and neck squamous cell carcinoma (HNSCC) patients. MicroRNAs (miRNAs) have been implicated in metastasis of HNSCC, but the mechanisms of their action are mainly undocumented. Through public head and neck cancer miRNA expression datasets, we found that miR-876-5p was a novel potential tumor suppressor targeting HNSCC metastasis.

METHODS

Clinical significance and mechanism of miR-876-5P was systematically analyzed in HNSCC. Quantitative RT-PCR was used to evaluate miR-876-5p levels in HNSCC cell lines and in 20 pairs of HNSCC with associated regional nodal metastases and HNSCC without metastatic primary tumors. Scratch and invasion assays were evaluated to determine the role of miR-876-5p in the regulation of HNSCC cell migration and invasion, respectively. Western blotting was used to investigate the mechanism by which miR-876-5p suppresses HNSCC cell invasion and migration. Luciferase assays were performed to assess miR-876-5p binding to the vimentin gene. The animal model was used to support the in vitro experimental findings.

RESULTS

MiR-876-5p mimics inhibited HNSCC cell migration and invasion. Vimentin protein and mRNA levels were decreased in the miR-876-5p mimics group but increased in the miR-876-5p inhibitors group, which demonstrated that miR-876-5p inhibits vimentin expression in HNSCC cells. By directly targeting the vimentin 3'-UTR, we used dual-luciferase reporter assays to verify that vimentin is a functional downstream target of miR-876-5p. Importantly, increased vimentin expression promoted cell migration and invasion, and co-transfection with miR-876-5p mimics and vimentin restored cell aggressiveness to the original level. Moreover, miR-876-5p overexpression significantly downregulated vimentin expression level and inhibited the distal metastasis of HNSCC cells in vivo.

CONCLUSIONS

miR-876-5p, which functions as a tumor suppressor in HNSCC, inhibits metastasis by targeting vimentin and provides a novel therapeutic target for HNSCC treatment.

MiRNA-16 inhibited oral squamous carcinoma tumor growth in vitro and in vivo via suppressing Wnt/β-catenin signaling pathway

Background

Oral carcinoma, one of the most commonly diagnosed cancers, has a poor prognosis and low survival rate with treatment. In recent years, some studies reported the upregulation of miRNA-16 (miR-16) in the oral carcinoma, whereas some other studies confirmed the downregulation of miR-16. In the current study, we aimed to investigate the function of miR-16 in oral carcinoma.

Materials and methods

Cell proliferation assay was measured by MTT assay, quantitative real time polymerase chain reaction (qRT-PCR) was used to evaluate the expression of miR-16, and apoptosis was analyzed by flow cytometry. In addition, the expression of proteins was detected by Western blot. Moreover, xenograft tumor model was established to detect the effect of miR-16 in vivo.

Results

The results suggested that miR-16 was downregulated in the oral carcinoma tissues. Overexpression of miR-16 inhibited the growth and proliferation of oral squamous carcinoma cells (OSCCs) and induced apoptosis both in vitro and in vivo, which is due to the suppression of Wnt/β-catenin signaling pathway.

Conclusion

This study provides evidence that overexpression of miR-16 inhibits OSCC growth by regulating Wnt/β-catenin signaling. Our findings suggest that overexpression of miR-16 could be a potential approach for gene therapy of OSCC in future.

TGF-β/SMAD signaling inhibits intermittent cyclic mechanical tension-induced degeneration of endplate chondrocytes by regulating the miR-455-5p/RUNX2 axis

A mechanical stimulation plays a pivotal role in maintaining normal cartilage function. Our objective was to reveal the mechanism of action of the tension-sensitive molecule miR-455-5p in the degeneration of endplate chondrocytes and to identify whether the transforming growth factor beta (TGF-β)/SMAD signaling pathway has a regulatory effect on it. The expression profiles of members of the TGF-β/SMAD pathway, miR-455-5p, and RUNX2 were determined by microRNA microarray analysis, reverse transcription quantitative polymerase chain reaction, luciferase reporter assay, and Western blot analysis. Intermittent cyclic mechanical tension (ICMT) induced the degeneration of endplate chondrocytes without affecting their viability. The tension-sensitive molecule miR-455-5p specifically bound to RUNX2, a gene involved in the degeneration of endplate chondrocytes. Activation of the TGF-β/SMAD signaling pathway upregulated miR-455-5p expression and thus inhibited RUNX2 levels. Therefore, the TGF-β/SMAD signaling pathway inhibits the ICMT-induced degeneration of endplate chondrocytes by regulating the miR-455-5p/RUNX2 axis.

Persistently elevated soluble MHC class I polypeptide-related sequence A and transforming growth factor-β1 levels are poor prognostic factors in head and neck squamous cell carcinoma after definitive chemoradiotherapy

We evaluated the prognostic significance of immunologic inhibitory biomarkers in head and neck squamous cell carcinoma (HNSCC) patients undergoing definitive chemoradiotherapy (CRT). Thirty patients were prospectively enrolled. Plasma levels of soluble MHC class I polypeptide-related sequence A (sMICA) and transforming growth factor-β1 (TGF-β1) were measured before and 2 weeks after CRT. The median follow-up was 32.9 months (range: 12.4-40.6 months). The pre-treatment sMICA (p < 0.001) and TGF-β1 (p < 0.001) levels were significantly increased in HNSCC patients, compared to healthy controls. In HNSCC patients, the median pre-CRT and post-CRT sMICA levels were 43.1 pg/mL and 65.3 pg/mL, respectively, while the median pre-CRT and post-CRT TGF-β1 levels were 57.7 ng/mL and 36.0 ng/mL, respectively. After CRT, 19 patients (63.3%) exhibited persistently elevated sMICA, six patients (20.0%) exhibited persistently elevated TGF-β1, and five patients (16.7%) exhibited persistently elevated sMICA and TGF-β1. Patients with persistently elevated sMICA and TGF-β1 after CRT experienced an earlier tumor progression (p = 0.030), and poor overall survival (p = 0.010). Our results suggest that HNSCC patients who exhibit persistently elevated sMICA and TGF-β1 levels after CRT are at higher risk of tumor progression or death.

Adenoid cystic carcinomas of the salivary gland, lacrimal gland, and breast are morphologically and genetically similar but have distinct microRNA expression profiles

Adenoid cystic carcinoma is among the most frequent malignancies in the salivary and lacrimal glands and has a grave prognosis characterized by frequent local recurrences, distant metastases, and tumor-related mortality. Conversely, adenoid cystic carcinoma of the breast is a rare type of triple-negative (estrogen and progesterone receptor, HER2) and basal-like carcinoma, which in contrast to other triple-negative and basal-like breast carcinomas has a very favorable prognosis. Irrespective of site, adenoid cystic carcinoma is characterized by gene fusions involving MYB, MYBL1, and NFIB, and the reason for the different clinical outcomes is unknown. In order to identify the molecular mechanisms underlying the discrepancy in clinical outcome, we characterized the phenotypic profiles, pattern of gene rearrangements, and global microRNA expression profiles of 64 salivary gland, 9 lacrimal gland, and 11 breast adenoid cystic carcinomas. All breast and lacrimal gland adenoid cystic carcinomas had triple-negative and basal-like phenotypes, while salivary gland tumors were indeterminate in 13% of cases. Aberrations in MYB and/or NFIB were found in the majority of cases in all three locations, whereas MYBL1 involvement was restricted to tumors in the salivary gland. Global microRNA expression profiling separated salivary and lacrimal gland adenoid cystic carcinoma from their respective normal glands but could not distinguish normal breast adenoid cystic carcinoma from normal breast tissue. Hierarchical clustering separated adenoid cystic carcinomas of salivary gland origin from those of the breast and placed lacrimal gland carcinomas in between these. Functional annotation of the microRNAs differentially expressed between salivary gland and breast adenoid cystic carcinoma showed these as regulating genes involved in metabolism, signal transduction, and genes involved in other cancers. In conclusion, microRNA dysregulation is the first class of molecules separating adenoid cystic carcinoma according to the site of origin. This highlights a novel venue for exploring the biology of adenoid cystic carcinoma.

microRNA-761 regulates glycogen synthase kinase 3β expression and promotes the proliferation and cell cycle of human gastric cancer cells

It has been well documented that aberrant expression of microRNAs (miRs) serves important roles in cancer progression. The present study investigated the roles of miR-761 on gastric cancer (GC) cell proliferation. Reverse transcription polymerase chain reaction indicated that miR-761 was frequently upregulated in GC tissues and cells. Overexpression of miR-761 promoted the cell proliferation, cell colony formation and cell cycle of GC cells. Bioinformatics analysis revealed that miR-761 might target the 3′-untranslated region of glycogen synthase kinase 3β, and was confirmed by luciferase reporter assay and western blot analysis. Taken together, the results of the present study revealed miR-761 as a tumor promoter in GC, and that it could be considered as a novel therapeutic target for patients with GC.

Targeting liver sinusoidal endothelial cells with miR-20a-loaded nanoparticles reduces murine colon cancer metastasis to the liver

Phenotypic transformation of liver sinusoidal endothelial cells is one of the most important stages of liver metastasis progression. The miRNA effects on liver sinusoidal endothelial cells during liver metastasis have not yet been studied. Herein, whole genome analysis of miRNA expression in these cells during colorectal liver metastasis revealed repressed expression of microRNA-20a. Importantly, downregulation of miR-20a occurs in parallel with upregulation of its known protein targets. To restore normal miR-20a levels in liver sinusoidal endothelial cells, we developed chondroitin sulfate-sorbitan ester nanoparticles conjugated with miR-20a in a delivery system that specifically targets liver sinusoidal endothelial cells. The restoration of normal mir-20a levels in these cells induced downregulation of the expression of its protein targets, and this also resulted in a reduction of in vitro LSEC migration and a reduction of in vivo activation and tumor-infiltrating capacity and ability of the tumor decreased by ∼80% in a murine liver metastasis model.

Predictive Prognostic Value of Tissue-Based MicroRNA Expression in Oral Squamous Cell Carcinoma: A Systematic Review and Meta-analysis

Oral squamous cell carcinoma (OSCC) is a common type of cancer characterized by a low survival rate, mostly due to local recurrence and metastasis. In view of the importance of predicting tumor behavior in the choice of treatment strategies for OSCC, several studies have attempted to investigate the prognostic value of tissue biomarkers, including microRNA (miRNA). The purpose of this study was to perform a systematic review and meta-analysis to evaluate the relationship between miRNA expression and survival of OSCC patients. Studies were identified by searching on MEDLINE/PubMed, SCOPUS, Web of Science, and Google Scholar. Quality assessment of studies was performed with the Newcastle-Ottawa Scale. Data were collected from cohort studies comparing disease-free survival and overall survival in patients with high miRNA expression compared to those with low expression. A total of 15 studies featuring 1,200 OSCC samples, predominantly from Asia, met the inclusion criteria and were included in the meta-analysis. Poor prognosis correlated with upregulation of 9 miRNAs (miR-21, miR-455-5p, miiR-155-5p, miR-372, miR-373, miR-29b, miR-1246, miR-196a, and miR-181) and downregulation of 7 miRNAs (miR-204, miR-101, miR-32, miR-20a, miR-16, miR-17, and miR-125b). The pooled hazard ratio values (95% confidence interval) related to different miRNA expression for overall survival and disease-free survival were 2.65 (2.07–3.39) and 1.95 (1.28–2.98), respectively. The results of this meta-analysis revealed that the expression levels of specific miRNAs can robustly predict prognosis of OSCC patients.

MicroRNA meta-signature of oral cancer: evidence from a meta-analysis

AIM

It was the aim of the study to identify commonly deregulated miRNAs in oral cancer patients by performing a meta-analysis of previously published miRNA expression profiles in cancer and matched normal non-cancerous tissue in such patients.

MATERIAL AND METHODS

Meta-analysis included seven independent studies analyzed by a vote-counting method followed by bioinformatic enrichment analysis.

RESULTS

Amongst seven independent studies included in the meta-analysis, 20 miRNAs were found to be deregulated in oral cancer when compared with non-cancerous tissue. Eleven miRNAs were consistently up-regulated in three or more studies (miR-21-5p, miR-31-5p, miR-135b-5p, miR-31-3p, miR-93-5p, miR-34b-5p, miR-424-5p, miR-18a-5p, miR-455-3p, miR-450a-5p, miR-21-3p), and nine were down-regulated (miR-139-5p, miR-30a-3p, miR-376c-3p, miR-885-5p, miR-375, miR-486-5p, miR-411-5p, miR-133a-3p, miR-30a-5p). The meta-signature of identified miRNAs was functionally characterized by KEGG enrichment analysis. Twenty-four KEGG pathways were significantly enriched, and TGF-beta signaling was the most enriched signaling pathway. The highest number of meta-signature miRNAs was involved in the sphingolipid signaling pathway. Natural killer cell-mediated cytotoxicity was the pathway with most genes regulated by identified miRNAs. The rest of the enriched pathways in our miRNA list describe different malignancies and signaling.

CONCLUSIONS

The identified miRNA meta-signature might be considered as a potential battery of biomarkers when distinguishing oral cancer tissue from normal, non-cancerous tissue. Further mechanistic studies are warranted in order to confirm and fully elucidate the role of deregulated miRNAs in oral cancer.

MicroRNA-455-3p as a Potential Biomarker for Alzheimer's Disease: An Update

A non-invasive and early-detectable peripheral biomarker is urgently needed for Alzheimer's disease (AD). The present study is a step forward to verify the biomarker properties of human microRNA-455-3p (Hsa-miR-455-3p) in AD patients. Our previous findings on mild cognitive impaired subjects, AD patients and AD cells and mouse models unveiled the miR-455-3p as a potential peripheral biomarker for AD. In the current study, we verified the differential expression of miR-455-3p in postmortem AD brains obtained from NIH NeuroBioBank, and fibroblasts and B-lymphocytes from both familial and sporadic AD patients from Coriell Cell Repository of National Institutes on Aging. Total RNA was extracted from the fibroblasts, B-lymphocytes and AD postmortem brains, and expression of miR-455-3p was measured by real-time reverse-transcriptase RT-PCR. Our real-time RT-PCR analysis showed a significant (P = 0.0002) upregulation of miR-455-3p expression in AD postmortem brains compared to healthy control samples. Expression of miR-455-3p was also upregulated in the fibroblasts from AD patients, however a significant difference in miR-455-3p level was observed in the cells from sporadic AD patients (P = 0.014) compared to healthy controls. Similarly, in B-lymphocytes, miR-455-3p level was also higher (P = 0.044) especially in sporadic AD cases compared to controls. Receiver operating characteristic (ROC) curve analysis indicated the significant area under ROC curve (AUROC) value of miR-455-3p in AD postmortem brain (AUROC = 0.792; P = 0.001) and AD fibroblasts cells (AUROC = 0.861; P = 0.03), whereas in B-lymphocytes AUROC value of miR-455-3p was not significant. Further, in-silico analysis for miRNA targets predictions showed the binding capacity of miR-455-3p with several AD associated key genes such as APP, NGF, USP25, PDRG1, SMAD4, UBQLN1, SMAD2, TP73, VAMP2, HSPBAP1, and NRXN1. Hence, these observations further revealed that miR-455-3p is a potential biomarker for AD and its possible therapeutic target for AD.

MicroRNAs as effective surrogate biomarkers for early diagnosis of oral cancer

BACKGROUND

Oral squamous cell carcinomas (OC) are life-threatening diseases emerging as major international health concerns.

OBJECTIVE

Development of an efficient clinical strategy for early diagnosis of the disease is a key for reducing the death rate. Biomarkers are proven to be an effective approach for clinical diagnosis of cancer. Although mechanisms underlying regulation of oral malignancy are still unclear, microRNAs (miRNAs) as a group of small non-coded RNAs may be developed as the effective biomarkers used for early detection of oral cancer.

METHODS

A literature search was conducted using the databases of PubMed, Web of Science, and the Cochrane Library. The following search terms were used: miRNAs and oral cancer or oral carcinoma. A critical appraisal of the included studies was performed with upregulated miRNAs and downregulated miRNAs in oral cancer.

RESULTS

In this review, we summarize the research progress made in miRNAs for diagnosis of oral cancer. The involvement of miRNAs identified in signal transduction pathways in OC, including Ras/MAPK signaling, PI3K/AKT signaling, JAK/STAT signaling, Wnt/β-catenin signaling, Notch signaling, and TGF-β/SMAD signaling pathway.

CONCLUSIONS

A number of studies demonstrated that miRNAs may be developed as an ideal set of biomarkers used for early diagnosis and prognosis of cancers because of the stability in human peripheral blood and body fluids and availability of non-invasive approaches being developed for clinical utility.

CLINICAL RELEVANCE

These findings suggest that miRNAs as biomarkers may be useful for diagnosis of OC.

Characteristic miRNA expression signature and random forest survival analysis identify potential cancer-driving miRNAs in a broad range of head and neck squamous cell carcinoma subtypes

AIM

To characterize the miRNA expression profile in head and neck squamous cell carcinoma (HNSSC) accounting for a broad range of cancer subtypes and consequently identify an optimal miRNA signature with prognostic value.

BACKGROUND

HNSCC is consistently among the most common cancers worldwide. Its mortality rate is about 50% because of the characteristic aggressive behavior of these cancers and the prevalent late diagnosis. The heterogeneity of the disease has hampered the development of robust prognostic tools with broad clinical utility.

MATERIALS AND METHODS

The Cancer Genome Atlas HNSC dataset was used to analyze level 3 miRNA-Seq data from 497 HNSCC patients. Differential expression (DE) analysis was implemented using the limma package and multivariate linear model that adjusted for the confounding effects of age at diagnosis, gender, race, alcohol history, anatomic neoplasm subdivision, pathologic stage, T and N stages, and vital status. Random forest (RF) for survival analysis was implemented using the randomForestSRC package.

RESULTS

A characteristic DE miRNA signature of HNSCC, comprised of 11 upregulated (i.e., miR-196b-5p, miR-1269a, miR-196a-5p, miR-4652-3p, miR-210-3p, miR-1293, miR-615-3p, miR-503-5p, miR-455-3p, miR-205-5p, and miR-21-5p) and 9 downregulated (miR-376c-3p, miR-378c, miR-29c-3p, miR-101-3p, miR-195-5p, miR-299-5p, miR-139-5p, miR-6510-3p, miR-375) miRNAs was identified. An optimal RF survival model was built from seven variables including age at diagnosis, miR-378c, miR-6510-3p, stage N, pathologic stage, gender, and race (listed in order of variable importance).

CONCLUSIONS

The joint differential miRNA expression and survival analysis controlling for multiple confounding covariates implemented in this study allowed for the identification of a previously undetected prognostic miRNA signature characteristic of a broad range of HNSCC.

Downregulation of MicroRNA-455-3p Links to Proliferation and Drug Resistance of Pancreatic Cancer Cells via Targeting TAZ

Drug resistance is a major cause of treatment failure in pancreatic cancer. The limited evidence indicates the involvement of miR-455-3p in chemotherapy resistance of cancer. Here we observed by qPCR that miR-455-3p was significantly decreased in pancreatic cancer tissues and cell lines. We then confirmed that the inhibition of miR-455-3p increased cell proliferation and gemcitabine resistance of pancreatic cancer, whereas forced overexpression of miR-455-3p had the opposite effect. Furthermore, we demonstrated that TAZ, which is associated with drug resistance of pancreatic cancer, is a new direct downstream target of miR-455-3p. Our present study suggests that miR-455-3p contributes to cell proliferation and drug resistance in pancreatic cancer cells via targeting TAZ.

miR‑455‑5p promotes cell invasion and migration in breast cancer

MicroRNA (miR)‑455‑5p has been identified as a biomarker for various types of cancer and may therefore be involved in the regulation of cancer development and progression. However, the specific role and function of miR‑455‑5p in breast cancer remains unclear. The present study explored the expression levels and function of miR‑455‑5p in breast cancer. The results from reverse transcription‑quantitative polymerase chain reaction analysis revealed that miR‑455‑5p was significantly upregulated in breast cancer. Clinically, increased expression of miR‑455‑5p predicted a poor survival rate and miR‑455‑5p was identified as one of the independent prognostic factors for breast cancer patients. Furthermore, results from wound healing and Transwell assays revealed that miR‑455‑5p accelerated invasiveness and migration capabilities of breast cancer cells. In addition, programmed cell death 4 was identified as a downstream target of miR‑455‑5p and its expression was observed to be negatively regulated by miR‑455‑5p. Overall, miR‑455‑5p may function as an oncogene in breast cancer, and may therefore be used as a prognostic marker for breast cancer patients.

miR-195-5p Suppresses the Proliferation, Migration, and Invasion of Oral Squamous Cell Carcinoma by Targeting TRIM14

MicroRNAs (miRNAs) play an essential role in tumor biological processes through interacting with specific gene targets. The involvement of miR-195-5p in cell proliferation, invasion, and migration has been demonstrated in several cancer cell lines, while its function in oral squamous cell carcinoma (OSCC) remains unclear. Here we find that miR-195-5p expression is lower in OSCC than in nontumor tissues, while its overexpression in cell lines can lead to the promotion of apoptosis and the reduction of cell growth, migration, and invasion. Moreover, we identify the tripartite motif-containing protein (TRIM14) as a target of miR-195-5p. Therefore, we reason that the tumor suppressor role of miR-195-5p in OSCC is dependent on the interaction with TRIM14.

The lncRNA PDIA3P Interacts with miR-185-5p to Modulate Oral Squamous Cell Carcinoma Progression by Targeting Cyclin D2

Long noncoding RNAs (lncRNAs) are emerging as important regulators during tumorigenesis by serving as competing endogenous RNAs (ceRNAs). In this study, the qRT-PCR results indicated that the lncRNA protein disulfide isomerase family A member 3 pseudogene 1 (PDIA3P) was overexpressed in oral squamous cell carcinoma (OSCC) and decreased the survival rate of OSCC patients. CCK-8 and clonal colony formation assays were used to detect the effects of PDIA3P on proliferation. Results revealed that silencing PDIA3P by small interfering RNA (siRNA) inhibited OSCC cell proliferation and repressed tumor growth and reduced the expression of proliferation antigen Ki-67 in vivo. Furthermore, the interaction between PDIA3P and miRNAs was then analyzed by qRT-PCR and luciferase reporter gene assay. We found that PDIA3P negatively regulated miR-185-5p in OSCC cells. Simultaneously, we found that silencing PDIA3P by siRNA suppressed proliferation via miR-185-5p in OSCC cells. Moreover, silencing PDIA3P by siRNA inhibited CCND2 protein (no influence on mRNA levels) expression via miR-185-5p in OSCC cells, and CCND2 facilitated cell proliferation of SCC4 and SCC15 cells induced by sh-PDIA3P#1. Therefore, our study demonstrated that PDIA3P may be a therapeutic target for the treatment of OSCC.

Antagonizing miR-455-3p inhibits chemoresistance and aggressiveness in esophageal squamous cell carcinoma

Background

The plasticity of cancer stem cells (CSCs)/tumor-initiating cells (T-ICs) suggests that multiple CSC/T-IC subpopulations exist within a tumor and that multiple oncogenic pathways collaborate to maintain the CSC/T-IC state. Here, we aimed to identify potential therapeutic targets that concomitantly regulate multiple T-IC subpopulations and CSC/T-IC-associated pathways.

Methods

A chemoresistant patient-derived xenograft (PDX) model of human esophageal squamous cell carcinoma (ESCC) was employed to identify microRNAs that contribute to ESCC aggressiveness. The oncogenic effects of microRNA-455-3p (miR-455-3p) on ESCC chemoresistance and tumorigenesis were examined by in vivo and in vitro chemoresistance, tumorsphere formation, side-population, and in vivo limiting dilution assays. The roles of miR-455-3p in activation of the Wnt/β-catenin and transforming growth factor-β (TGF-β)/Smad pathways were determined by luciferase and RNA immunoprecipitation assays.

Results

We found that miR-455-3p played essential roles in ESCC chemoresistance and tumorigenesis. Treatment with a miR-455-3p antagomir dramatically chemosensitized ESCC cells and reduced the subpopulations of CD90⁺ and CD271⁺ T-ICs via deactivation of multiple stemness-associated pathways, including Wnt/β-catenin and TGF-β signaling. Importantly, miR-455-3p exhibited aberrant upregulation in various human cancer types, and was significantly associated with decreased overall survival of cancer patients.

Conclusions

Our results demonstrate that miR-455-3p functions as an oncomiR in ESCC progression and may provide a potential therapeutic target to achieve better clinical outcomes in cancer patients.

Electronic supplementary material

The online version of this article (doi:10.1186/s12943-017-0669-9) contains supplementary material, which is available to authorized users.

Long intergenic non-coding RNA 668 regulates VEGFA signaling through inhibition of miR-297 in oral squamous cell carcinoma

Recently, long noncoding RNAs (lncRNAs) have been reported to have crucial regulatory efficiency in human cancer biology. Long intergenic non-coding RNA 668 (LINC00668) was regarded as an oncogene in multiple cancers. However, the underlying molecular mechanism of LINC00668 in oral squamous cell carcinoma (OSCC) has not been studied. In this study, we first demonstrated that LINC00668 expression was up-regulated, which was correlated with tumor progression, and miR-297 down-regulated in OSCC tissues and cells. Importantly, LINC00668 expression was negatively correlated with miR-297 expression in OSCC tissues. Loss-of-function of LINC00668 revealed that LINC00668 functioned as a ceRNA for miR-297 to facilitate VEGFA expression, promoting OSCC progression. Furthermore, LINC00668 knockdown suppressed tumor growth and reduced the expression of proliferation antigen ki-67 in vivo. Finally, we confirmed that LINC00668 promoted OSCC activity through VEGFA signaling. In conclusion, these results suggest that LINC00668 promotes OSCC tumorigenesis via miR-297/VEGFA axis, which may provide a new target for the diagnosis and therapy of OSCC disease.

The trophoblast cell surface antigen 2 and miR-125b axis in urothelial bladder cancer

Human trophoblast cell surface antigen 2 (Trop-2) is a 40-kDa transmembrane glycoprotein that was first identified as a marker of human trophoblast cells. Trop-2 acts on cell proliferation, adhesion, and migration by activating a number of intracellular signalling pathways. Elevated Trop-2 expression has been demonstrated in several types of cancer and correlated with aggressiveness and poor prognosis. Since no data are available on Trop-2 in bladder cancer (BC), the purpose of the study was to determine its levels in tissue specimens from normal individuals and patients with BC at different stages. Moreover, since according to recent evidence Trop-2 is a miR-125b target, miR-125b expression was also assessed in tissue specimens. Finally, the effect of the Trop-2/miR-125b axis on the proliferation and migration of BC cells was evaluated in vitro.

The Trop-2/miR-125b axis was seen to be differentially expressed in normal urothelium, non-invasive BC and invasive BC tissue. Significant miR-125b down-regulation was associated with a significant increase in Trop-2 protein levels in BC tissue and correlated with disease severity. In vitro analysis confirmed the role of miR-125b in down-modulation of Trop-2 protein levels and showed that Trop-2/miR-125b axis affects cellular proliferation in bladder tissue.

In conclusion, our findings highlight a role for the Trop-2/miR-125b axis in BC progression and suggest Trop-2 and miR-125b as diagnostic/prognostic marker candidates as well as druggable targets for innovative therapeutic approaches.