miR-302b is a potential molecular marker of esophageal squamous cell carcinoma and functions as a tumor suppressor by targeting ErbB4

Advances in MicroRNA Therapeutics: from Preclinical to Clinical Studies

MicroRNAs (miRNAs) are crucial regulators of gene expression involved in various pathophysiological processes. Their ability to modulate multiple pathways simultaneously and their involvement in numerous diseases make miRNAs attractive tools and targets in therapeutic development. Significant efforts have been made to advance miRNA research in the preclinical stage, attracting considerable investment from biopharmaceutical companies. Consequently, an increasing number of miRNA-based therapies have entered clinical trials for both diagnostic and therapeutic applications across a wide range of diseases. While individual miRNAs can regulate a broad array of mRNA targets, this also complicates the management of adverse effects seen in clinical trials. Several candidates have been discontinued due to toxicity concerns, underscoring the need for comprehensive risk assessments of miRNA therapeutics. Despite no miRNA-based strategies have yet received approval from regulatory agencies, prominent progress in the miRNAs modulation approaches and in the nano-delivery systems have been made in the last decade, leading to the development of novel safe and well-tolerated miRNA drug candidates. In this review, we present recent advances in the development of miRNA therapeutics currently in preclinical or clinical stages for treating both rare genetic disorders and multifactorial common conditions. We also address the challenges related to the safety and targeted delivery of miRNA therapies, as well as the identification of the most effective therapeutic candidates in preclinical and clinical trials.

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.

Mig6 not only inhibits EGFR and HER2 but also targets HER3 and HER4 in a differential specificity: Implications for targeted esophageal cancer therapy

The human EGF receptor family plays pivotal roles in physiology and cancer, which contains four closely-related members: HER1/EGFR, HER2, HER3 and HER4. Previously, it was found that the mitogen-inducible gene 6 (Mig6) protein is a negative regulator of EGFR and HER2 by using its S1 segment to bind at the kinase dimerization interface. However, it is still unclear whether the S1 segment can also effectively target HER3 and HER4? Here, we performed a systematic investigation to address this issue. The segment can bind to all the four HER kinases with a varying affinity and moderate selectivity; breaking of the segment into shorter hotspot peptides would largely impair the affinity and selectivity, indicating that the full-length sequence is required for the effective binding of S1 to these kinases. The hs2 peptide, which corresponds to the middle hotspot region of S1 segment, can partially retain the affinity to HER kinases, can moderately compete with S1 segment at the dimerization interfaces, and can mimic the biological function of Mig6 protein to suppress HER4+ esophageal cancer at cellular level. In addition, we also analyzed the binding potency of S1 segment and hs2 peptide to the kinase domains of other five widely documented growth factor receptors (GFRs). It was showed that both the S1 and hs2 cannot effectively interact with these receptors. Overall, the Mig6 is suggested as a specific pan-HER inhibitor, which can target and suppress HER family members with a broad selectivity, but exhibits weak or no activity towards other GFRs.

MicroRNA-302s Might Regulate ARL4C-Mediated Gastric Cancer Progression via p53 Signaling: Bioinformatics Analysis and Experiments Validation

Background

Our previous studies demonstrate that ARL4C is the most critical clinical biomarker for gastric cancer (GC) patients among ARL family members (ARLs) and functions as an oncogene in GC. However, its underlying mechanisms in GC need to be further illustrated. In this study, we aim to explore the upstream and downstream molecular mechanisms of ARL4C in GC cells.

Methods

The genetic alteration of ARL4C in GC is analyzed by cBioPortal database. Potential ARL4C-targeted microRNAs (miRs) are predicted by three databases. The high-throughput RNA sequencing is performed to explore the underlying mechanisms of ARL4C in GC cells. The effects of predicted microRNAs on ARL4C, the RNA-sequencing results validation and the biological functions of ARL4C in GC cells are illustrated by in vitro experiments.

Results

Genetic analyses indicate that ARL4C is significantly upregulated in GC, which is not caused by gene amplification. MicroRNAs prediction shows the high relevance between ARL4C and miR-302 members. Moreover, miR-302c or miR-302d transfection reduces ARL4C protein expression in GC cells. Based on the high-throughput RNA sequencing of ARL4C-knockdown cells, enrichment analyses demonstrate that ARL4C is closely related to cell growth and involved in p53 signaling. Moreover, there are strong gene–gene interactions between ARL4C and genes in p53 signaling, and ARL4C downregulation could inhibit the protein expression of MDM2, a critical gene in p53 pathway. Further functional experiments demonstrate that ARL4C silencing leads to cell cycle arrest and increased cell apoptosis in AGS and MKN45 cells.

Conclusion

Our data suggest that miR-302c and miR-302d may function as the upstream regulators of ARL4C. And, ARL4C might promote GC cell cycle progression via regulating p53 signaling. Our findings provide novel insights into the key role of ARL4C and the underlying mechanisms in GC progression, thus facilitating the development of ARL4C-targeted therapy.

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.

MiR-302b Suppresses Tumor Metastasis by Targeting Frizzled 6 in OSCC

Oral squamous cell carcinoma (OSCC) accounts for approximately 90% of malignant epithelial tumors of the oral and maxillofacial region. OSCC has high rate of metastasis and poor prognosis. Tobacco and/or alcohol consumption and human papillomavirus infection are relatively exact susceptibility factors for OSCC, but the specific process of oral mucosal carcinogenesis and progression is very complicated. microRNA-302b (miR-302b) could regulate various characteristics of many tumor cells, such as proliferation and apoptosis, but its role and mechanism in OSCC have not been reported. This research aims to study the effect of miR-302b on the invasion and migration ability of OSCC and the mechanism by which it functions as well as to identify new prognostic indicators and therapeutic targets for OSCC patients. Functional studies showed that the miR-302b level was negatively correlated with the invasion and migration ability of OSCC. The studies also showed that the overexpression of miR-302b could attenuate the invasion and migration ability of OSCC cells and reduce lymphangiogenesis and the lung metastasis rate of OSCC cells in a mouse model. Mechanistic studies were performed by quantitative polymerase chain reactions, luciferase assays, and RNA pull-down experiments. The results verified that frizzled class receptor 6 (FZD6) is a target gene of miR-302b in OSCC that could promote cell invasion and migration. Clinical studies demonstrate that the protein expression level of FZD6 was higher in OSCC and metastatic lymph nodes than in normal oral mucosa epithelium. Taken together, these data showed that miR-302b could inhibit the invasion and migration ability of OSCC cells by targeting and downregulating FZD6, thereby inhibiting OSCC metastasis. As a new target gene of miR-302b, FZD6 has the potential to become a prognostic and therapeutic target for OSCC patients.

Cytokine-chemokine network driven metastasis in esophageal cancer; promising avenue for targeted therapy

Esophageal cancer (EC) is a disease often marked by aggressive growth and poor prognosis. Lack of targeted therapies, resistance to chemoradiation therapy, and distant metastases among patients with advanced disease account for the high mortality rate. The tumor microenvironment (TME) contains several cell types, including fibroblasts, immune cells, adipocytes, stromal proteins, and growth factors, which play a significant role in supporting the growth and aggressive behavior of cancer cells. The complex and dynamic interactions of the secreted cytokines, chemokines, growth factors, and their receptors mediate chronic inflammation and immunosuppressive TME favoring tumor progression, metastasis, and decreased response to therapy. The molecular changes in the TME are used as biological markers for diagnosis, prognosis, and response to treatment in patients. This review highlighted the novel insights into the understanding and functional impact of deregulated cytokines and chemokines in imparting aggressive EC, stressing the nature and therapeutic consequences of the cytokine-chemokine network. We also discuss cytokine-chemokine oncogenic potential by contributing to the Epithelial-Mesenchymal Transition (EMT), angiogenesis, immunosuppression, metastatic niche, and therapeutic resistance development. In addition, it discusses the wide range of changes and intracellular signaling pathways that occur in the TME. Overall, this is a relatively unexplored field that could provide crucial insights into tumor immunology and encourage the effective application of modulatory cytokine-chemokine therapy to EC.

MiR-302b as a Combinatorial Therapeutic Approach to Improve Cisplatin Chemotherapy Efficacy in Human Triple-Negative Breast Cancer

Introduction: Chemotherapy is still the standard of care for triple-negative breast cancers (TNBCs). Here, we investigated miR-302b as a therapeutic tool to enhance cisplatin sensitivity in vivo and unraveled the molecular mechanism. Materials and Methods: TNBC-xenografted mice were treated with miR-302b or control, alone or with cisplatin. Genome-wide transcriptome analysis and independent-validation of Integrin Subunit Alpha 6 (ITGA6) expression was assessed on mice tumor samples. Silencing of ITGA6 was performed to evaluate cisplatin response in vitro. Further, potential transcription factors of ITGA6 (E2F transcription facor 1 (E2F1), E2F transcription factor 2 (E2F2), and Yin Yang 1 (YY1)) were explored to define the miRNA molecular mechanism. The miR-302b expression was also assessed in TNBC patients treated with chemotherapy. Results: The miR–302b-cisplatin combination significantly impaired tumor growth versus the control through indirect ITGA6 downregulation. Indeed, ITGA6 was downmodulated in mice treated with miR-302b–cisplatin, and ITGA6 silencing increased drug sensitivity in TNBC cells. In silico analyses and preclinical assays pointed out the regulatory role of the E2F family and YY1 on ITGA6 expression under miR-302b–cisplatin treatment. Finally, miR-302b enrichment correlated with better overall survival in 118 TNBC patients. Conclusion: MiR-302b can be exploited as a new therapeutic tool to improve the response to chemotherapy, modulating the E2F family, YY1, and ITGA6 expression. Moreover, miR-302b could be defined as a new prognostic factor in TNBC patients.

Regulatory mechanism of tumor suppressor gene miR-302b in malignant tumors

MicroRNAs are a class of endogenous non-coding RNA molecules that regulate the translation of proteins. They play important regulatory roles in the growth, development, and aging of organisms, as well as cell proliferation, differentiation, apoptosis, and even cancer. miR-302b can participate in the regulation of the expression of a variety of genes, and functions as a tumor suppressor gene in the occurrence, development, invasion, and metastasis of malignant tumors. This article discusses the expression of miR-302b in malignant tumors and its biological functions and molecular mechanism.

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.

Identification and validation of hub microRNAs dysregulated in esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is one of the deadliest cancers worldwide, and its morbidity is exacerbated by the lack of early symptoms. Bioinformatics analyses enable discovery of differentially expressed genes and non-protein-coding RNAs of potential prognostic and/or therapeutic relevance in ESCC and other cancers. Using bioinformatics tools, we searched for dysregulated miRNAs in two ESCC microarray datasets from the Gene Expression Omnibus (GEO) database. After identification of three upregulated and five downregulated miRNAs shared between databases, protein-protein interaction (PPI) network analysis was used to identify the top 10 hub-gene targets. Thereafter, a miRNA-gene interaction network predicted that most hub genes are regulated by miR-196a-5p and miR-1-3p, which are respectively upregulated and downregulated in ESCC. Functional enrichment analyses in the GO and KEGG databases indicated the potential involvement of these miRNAs in tumorigenesis-related processes and pathways, while both differential expression and correlation with T stage were demonstrated for each miRNA in a cohort of ESCC patients. Overexpression showed that miR-196a-5p increased, whereas miR-1-3p attenuated, proliferation and invasion in human ESCC cell lines grown in vitro. These findings suggest miR-196a-5p and miR-1-3p jointly contribute to ESCC tumorigenesis and are potential targets for diagnosis and treatment.

Application of the microRNA-302/367 cluster in cancer therapy

As a novel class of noncoding RNAs, microRNAs (miRNAs) can effectively silence their target genes at the posttranscriptional level. Various biological processes, such as cell proliferation, differentiation, and motility, are regulated by miRNAs. In different diseases and different stages of disease, miRNAs have various expression patterns, which makes them candidate prognostic markers and therapeutic targets. Abnormal miRNA expression has been detected in numerous neoplastic diseases in humans, which indicates the potential role of miRNAs in tumorigenesis. Previous studies have indicated that miRNAs are involved in nearly the entire process of tumor development. MicroRNA‐302a, miR‐302b, miR‐302c, miR‐302d, and miR‐367 are members of the miR‐302/367 cluster that plays various biological roles in diverse neoplastic diseases by targeting different genes. These miRNAs have been implicated in several unique characteristics of cancer, including the evasion of growth suppressors, the sustained activation of proliferative signaling, the evasion of cell death and senescence, and the regulation of angiogenesis, invasion, and metastasis. This review provides a critical overview of miR‐302/367 cluster dysregulation and the subsequent effects in cancer and highlights the vast potential of members of this cluster as therapeutic targets and novel biomarkers.

miR-520b Promotes Breast Cancer Stemness Through Hippo/YAP Signaling Pathway

Introduction

The breast cancer stem cells contribute to the initiation, progression, recurrence, metastasis as well as resistance of breast cancer. However, the mechanisms underlying the maintenance of breast cancer stemness have not been fully understood.

Materials and methods

TCGA and GEO data were used for measuring miR-520b expression in breast cancer tissues. Kaplan-meier analysis was used for determining the relationship between miR-520b expression level and the prognosis of patients. Genetic manipulation was performed by lentivirus system and miR-520b inhibitor was used for knockdown of miR-520b. qRT-PCR and Western blot were employed to determine the mRNA and protein levels, respectively. The stemness and EMT (Epithelial to mesenchymal transition) were assessed by sphere-formation and transwell assay as well as the expression of the related markers. The target genes of miR-520b were identified using the online database starBase V3.0.

Results

miR-520b is upregulated in cancer tissues of breast cancer patients and predicts poor prognosis. Upregulation of miR-520b was found in breast cancer stem cells. Ectopic expression of miR-520b promotes the stemness of the breast cancer cells, conversely, depletion of miR-520b attenuates the stemness of these cells. miR-520b positively regulates Hippo/YAP signaling pathway and overexpression of LAST2 abolished the effect of miR-520b on the stemness of breast cancer cells.

Conclusion

miR-520b promotes the stemness of breast cancer patients by activating Hippo/YAP signaling via targeting LATS2.

Downregulation of miR-302b is associated with poor prognosis and tumor progression of breast cancer

BACKGROUND

MicroRNAs (miRNAs) are well known to play crucial role in various types of cancers, including breast cancer (BC).

METHODS

The present study aimed to investigate the expression, clinical value, and functional role of miR-302b in BC. The expression level of miR-302b was determined by quantitative real-time polymerase chain reaction (qRT-PCR). The clinical value of miR-302b in BC prognosis was calculated via Kaplan-Meier survival analysis and Cox regression analysis. Cell experiments were applied to investigate the functional role of miR-302b in BC.

RESULTS

miR-302b was significantly downregulated in BC tissues and cell lines compared to the corresponding controls (all P < 0.01). Notably, the expression of miR-302b was significantly associated with lymph node metastasis and TNM stage (all P < 0.05). Patients with lower miR-302b expression had shorter survival time than those with higher miR-302b expression (log-rank P = 0.002). Furthermore, miR-302b expression and TNM stage were proven to be independent prognostic factors for BC. Overexpression of miR-302b inhibited BC cell proliferation, migration, and invasion in BT549 and MCF-7 cell lines, while silence of miR-302b exhibited an opposite effects on BC cells (all P < 0.05). RUNX2 was determined to be the target gene of miR-302b.

CONCLUSIONS

The present study suggests that miR-302b functions as a tumor suppressor in BC and inhibits the tumor progression of BC via targeting RUNX2. Downregulation of miR-302b might be a significant prognostic factor for poor survival in BC patients.

MicroRNA-365 suppresses cell growth and invasion in esophageal squamous cell carcinoma by modulating phosphoserine aminotransferase 1

Background

A number of studies have indicated that expression of miRNA-365 (miR-365) is suppressed in various cancers, suggesting its cancer-suppressive role. In the present investigation, we evaluated the regulation and character of miR-365 in human esophageal squamous cell carcinoma (ESCC).

Patients and methods

The tumor tissues and adjacent nontumor tissue samples were collected from 30 patients having ESCC, and the expression levels of miR-365 were studied by quantitative real-time polymerase chain reaction (PCR). MTT and cell invasion by Matrigel assay were done to study the effect of miR-365 on proliferation and metastasis of ESCC cells. An in vivo tumor model was generated by inoculating ESCC cells subcutaneously into BALB nude mice. A study of various biomarkers such as quantitative polymerase chain reaction (qPCR), luciferase activity assay, and Western blot was done to confirm the targets of miR-365.

Results

In tumor tissues, a significant downregulation of miR-365 was observed versus the nontumor adjacent tissues and ESCC cells versus the selected esophageal endothelial cells. It was observed that higher expression levels of miR-365 inhibited the cell invasion, colony formation, growth in esophageal cancer cell lines in vitro, and tumor development in vivo. The study of biomarkers suggests involvement of phosphoserine aminotransferase 1 (PSAT1) as a favorable target for miR-365, and its abnormal expression inverted the miR-365-arbitrated suppression of invasion, viability, and epithelial-mesenchymal transition in esophageal cancer cells. A negative correlation existed with expression of miR-365 and PSAT1 in human esophageal cancer tissue samples.

Conclusion

The study established that miR-365 exhibits tumor-suppressive action via regulating the levels of PSAT1 and leads to invasion and progressiveness of esophageal cancer.

MiR-302b regulates cell functions and acts as a potential biomarker to predict recurrence in bladder cancer

BACKGROUND

Bladder cancer is the most common urogenital tumor with substantial morbidity, high recurrence rate and mortality. miRNAs, a class of endogenous noncoding RNA, were found to involve in the genesis, maintenance and metastasis of cancer. Genomic profiling revealed that miR-302b is down-regulated in bladder cancer while its functions in bladder cancer remain to be ascertained.

METHODS

Cell functional assays including wound healing assay, CCK-8 assay, Transwell assay and flow cytometry assay were performed to clarify the functions of miR-302b expression in cell proliferation, migration, invasion and apoptosis in BC. Furthermore, RT-qPCR was performed to study the expression of miR-302b in bladder cancer tissues and the prognostic value of altered miR-302b expression with 48 formalin-fixed paraffin-embedded bladder urothelial carcinoma samples.

RESULTS

The results of RT-qPCR demonstrated that expression level of miR-302b was significantly reduced in bladder cancer tissues and cell lines. The cells after transfected with miR-302b mimic showed lower mobility, lower proliferation and increased apoptosis, while opposite results were obtained after inhibiting the expression of miR-302b. The prognosis analysis demonstrated that the patients with low expression of miR-302b experienced high risks of recurrence.

CONCLUSIONS

The results of our study demonstrate that miR-302b regulates cell functions and acts as a potential biomarker to predict recurrence in bladder cancer.

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.

Prognostic value of EGFR family expression in lymph node-negative esophageal squamous cell carcinoma patients

The human epidermal growth factor receptor (EGFR) family has been widely studied in cancer, however, the prognostic role of EGFR family expression in lymph node-negative esophageal squamous cell carcinoma (ESCC) patients have not been invalidated. This study was designed to determine the prognostic value of EGFR family expression in a population of lymph node-negative ESCC patients treated with curative resection. EGFR family protein expression was examined by immunohistochemical analysis of tissue microarrays of 94 patients with lymph node-negative ESCC after radical esophagectomy with three-field lymphadenectomy. Survival differences were compared using Kaplan-Meier analysis. Cox regression analyses were performed to determine the prognostic factors for overall survival and disease-free survival (DFS). ErbB4 expression was found to be an independent prognostic factor for DFS in patients without lymph node metastasis; increased ErbB4 expression was associated with decreased DFS. Additionally, patients with high ErbB4 expression tended to have worse overall survival. EGFR, ErbB2 and ErbB3 expression were not significantly associated with survival in lymph node-negative ESCC patients. Increased ErbB4 immunohistochemical expression was associated with poor prognosis in lymph node-negative ESCC patients.

miR-302b inhibits cancer-related inflammation by targeting ERBB4, IRF2 and CXCR4 in esophageal cancer

Cancer related inflammation (CRI) plays an important role in the development of esophageal cancer (EC), and the target gene analysis shows that miR-302b potential target genes closely correlated to CRI important signaling pathways. The present study was to evaluate the inhibition of miR-302b on CRI in EC and its mechanism. We found that the expression levels of miR-302b in EC cells were lower than that in Het-1A cells, while TE11 with the lowest expression and OE33 with the highest. Inflammatory stimuli at 48 h significantly reduced expression of miR-302b in EC cells, but had no effect in Het-1A. After up-regulation of miR-302b in TE11 and down-regulation of miR-302b in OE33, it was found that miR-302b reduced CRI key transcription factors and representative cytokines. Then, over-expressed of miR-302b significantly altered potential target genes protein expressions and there was a negative correlation between miR-302b and potential target genes protein expressions (ERBB4, IRF2 and CXCR4) in EC tissues. Then reporter gene analysis revealed that miR-302b post-transcriptionally regulated expression of target genes by specific area of 3′-UTR. Transfected by target genes shRNA plasmids together could get the same effects of miR-302b on protein expression of CRI key transcription factors. Furthermore, miR-302b was able to repress tumor growth and transcription factors protein expression in vivo. These finding suggests that miR-302b inhibits key transcription factors and cytokines by targeting ERBB4, IRF2 and CXCR4, implicating its role in the inhibition of CRI in EC.

A genetic variant of miR-335 binding site in the ERBB4 3'-UTR is associated with prognosis of ovary cancer

Ovarian cancer is one of the leading gynecologic malignancies globally, the 5-year survival rate for patients with advanced stage ovarian cancer is very low. Our objective was to test the hypothesis that miR-335 was associated with the survival of patients with ovarian cancer. Bioinformatics tools and luciferase report assay were used to select the target of miR-335, and real-time PCR was used to detect the expression of miR-335 and ERBB4 in different genotype groups. Finally, Cox regression and Kaplan-Meier analyses were used to assess the relationship of ERBB4 genotype and survival of ovary cancer. Firstly, individuals carried ERBB4 rs186724 GG genotype had poorer overall survival compared with those carried CC/CT genotypes in ovarian cancer, while the participants with rs1836724 GA genotype had the same overall survival with that in participants with rs1836724 AA genotype in accordance with the result of Cox regression and Kaplan-Meier analyses. Then according to result of the in-silicon analysis, ERBB4 was the target of miR-335, and rs1836724 was located on 3'UTR of ERBB4, the binding site of miR-335, and miR-335 inhibited the expression of ERBB4 and this regulation was more suppressed when the G allele replaced by the variant A allele. Finally, miR-335 was similar among GG, GA, and AA groups, and ERBB4 level was higher in GG group. Finally, malignant grade is apparently higher in GG group than the other group. The data indicated that the ERBB4 rs1836724 polymorphism was associated with the survival of ovarian cancer.

MicroRNA-302b negatively regulates IL-1β production in response to MSU crystals by targeting IRAK4 and EphA2

Background

Interleukin-1β (IL-1β) is a pivotal proinflammatory cytokine that is strongly associated with the inflammation of gout. However, the underlying mechanism through which the production of IL-1β is regulated has not been fully elucidated. Our previous work identified that miR-302b had an important immune regulatory role in bacterial lung infections. This study was conducted to evaluate the function of miR-302b on monosodium urate (MSU) crystal-induced inflammation and its mechanism.

Methods

The expression pattern and the immune-regulatory role of miR-302b were evaluated both in vitro and in vivo. The functional targets of miR-302b were predicted by bioinformatics, and then validated by genetic approaches. In addition, the clinical feature of miR-302b was analyzed using serum samples of patients with gouty arthritis.

Results

The extremely high expression of miR-302b was observed in both macrophages and mouse air membranes treated with MSU. Intriguingly, overexpression of miR-302b regulated NF-κB and caspase-1 signaling, leading to significantly attenuate MSU-induced IL-1β. By genetic analysis, miR-302b exhibited inhibitory function on IRAK4 and EphA2 by binding to their 3′-UTR regions. Corporately silencing IRAK4 and EphA2 largely impaired MSU-induced IL-1β protein production. Moreover, it was also found that miR-302b and EphA2 suppressed the migration of macrophages. Finally, it was observed that high expression of miR-302b was a general feature in patients with gouty arthritis.

Conclusions

These results suggest that miR-302b can regulate IL-1β production in MSU-induced inflammation by targeting NF-κB and caspase-1 signaling, and may be a potential therapeutic target for gouty arthritis.

Electronic supplementary material

The online version of this article (10.1186/s13075-018-1528-9) contains supplementary material, which is available to authorized users.

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.

Therapeutic effects of tyroserleutide on lung metastasis of human hepatocellular carcinoma SK-HEP-1 and its mechanism affecting ICAM-1 and MMP-2 and -9

BACKGROUND

Tyroserleutide (YSL) inhibits the growth and metastasis of human hepatocellular carcinoma (HCC). This paper studied the effect of YSL on metastasis of human HCC and investigated its mechanisms.

METHODS

In vivo, experimental lung metastasis models of human HCC SK-HEP-1 cells in nude mice were established, and In vitro, the proliferation, adhesion and invasion of SK-HEP-1 cells were detected.

RESULTS

In vivo, YSL significantly inhibited the metastasis of human HCC. In vitro, YSL significantly inhibited the proliferation, adhesion and invasion of SK-HEP-1 cells. Through analyses with reverse transcription PCR (RT-PCR) and Western blot, we observed that YSL significantly inhibited the expressions of ICAM-1 in SK-HEP-1 cells. Through RT-PCR, Western blot and zymography methods, YSL was discovered to decrease the mRNA level, protein expression and activity of MMP-2 and -9 in SK-HEP-1 cells.

CONCLUSION

We concluded that YSL could inhibit tumor growth and metastasis of human HCC SK-HEP-1 cells.

miR-302b inhibits tumorigenesis by targeting EphA2 via Wnt/ β-catenin/EMT signaling cascade in gastric cancer

Background

EphA2 is a crucial oncogene in gastric cancer (GC) development and metastasis, this study aims to identify microRNAs that target it and serve as key regulators of gastric carcinogenesis.

Methods

We identified several potential microRNAs targeting EphA2 by bioinformatics websites and then analyzed the role of miR-302b in modulating EphA2 in vitro and in vivo of GC, and it’s mechanism.

Results

Our analysis identified miR-302b, a novel regulator of EphA2, as one of the most significantly downregulated microRNA (miRNA) in GC tissues. Overexpression of miR-302b impaired GC cell migratory and invasive properties robustly and suppressed cell proliferation by arresting cells at G0–G1 phase in vitro. miR-302b exhibited anti-tumor activity by reversing EphA2 regulation, which relayed a signaling transduction cascade that attenuated the functions of N-cadherin, β-catenin, and Snail (markers of Wnt/β-catenin and epithelial-mesenchymal transition, EMT). This modulation of EphA2 also had distinct effects on cell proliferation and migration in GC in vivo.

Conclusions

miR-302b serves as a critical suppressor of GC cell tumorigenesis and metastasis by targeting the EphA2/Wnt/β-catenin/EMT pathway.

Electronic supplementary material

The online version of this article (10.1186/s12885-017-3875-3) contains supplementary material, which is available to authorized users.

MiR-302b Suppresses Osteosarcoma Cell Migration and Invasion by Targeting Runx2

Osteosarcoma patients with lung metastasis and local invasion remain challenging to treat despite the significant contribution of the combination of surgery and neo-adjuvant chemotherapy. Our previous microarray study demonstrated that miR-302b had significantly lower expression in osteosarcoma cell lines than in osteoblast cell lines. In the present study, we further elucidated the role of miR-302b in regulating the migration and invasiveness of osteosarcoma. MiR-302b expression was markedly down-regulated in osteosarcoma cell lines and clinical tumour tissues. Lower levels of miR-302b expression were significantly associated with metastasis and high pathological grades. A functional study demonstrated that over-expression of miR-302b suppressed tumour cell proliferation, invasion and migration in vitro and in vivo. Runx2 was identified as a direct target gene for miR-302b by bioinformatics analysis and dual-luciferase reporter gene assay. Moreover, over-expression of miR-302b induced down-regulation of Runx2, OPN, MMP-2, MMP-9, MMP-12, MMP-14, and VEGF in 143B cells. Exogenous expression of Runx2 partially rescued the inhibitory effect of miR-302b on the invasion and migration activity of 143B osteosarcoma cells. Taken together, our results indicate that miR-302b functions as a tumour repressor in the invasion and migration of osteosarcoma by directly downregulating Runx2 expression and may be a potential therapeutic target for osteosarcoma.

MiR-520b as a novel molecular target for suppressing stemness phenotype of head-neck cancer by inhibiting CD44

Cancer stem cells preferentially acquire the specific characteristics of stress tolerance and high mobility, allowing them to progress to a therapy-refractive state. To identify a critical molecule to regulate cancer stemness is indispensable to erratically cure cancer. In this study, we identified miR-520b as a novel molecular target to suppress head-neck cancer (HNC) with stemness phenotype. MiR-520b inhibited cellular migration and invasion via the mechanism of epithelial-mesenchymal transition. It also sensitized cells to therapeutic drug and irradiation. Significantly, miR-520b suppressed spheroid cell formation, as well as reduced expressions of multiple stemness regulators (Nestin, Twist, Nanog, Oct4). The CD44 molecule was identified as a direct target of miR-520b, as shown by the reverse correlative expressions, the response to miR-520 modulation, the luciferase reporter assay, and the functional rescue analyses. These cellular results were confirmed by a tumor xenograft mice study. Administration of miR-520b dramatically restrained tumorigenesis and liver colonization. Conversely, miR-520b silencing led to an acceleration of tumor growth. Taken together, our study demonstrated that miR-520b inhibits the malignancy of HNC through regulation of cancer stemness conversion by targeting CD44. MiR-520b may serve as an emerging therapeutic target that may be further developed for the intervention of refractory HNC.

The microRNA-302b-inhibited insulin-like growth factor-binding protein 2 signaling pathway induces glioma cell apoptosis by targeting nuclear factor IA

MicroRNAs are small noncoding RNAs that post-transcriptionally control the expression of genes involved in glioblastoma multiforme (GBM) development. Although miR-302b functions as a tumor suppressor, its role in GBM is still unclear. Therefore, this study comprehensively explored the roles of miR-302b-mediated gene networks in GBM cell death. We found that miR-302b levels were significantly higher in primary astrocytes than in GBM cell lines. miR-302b overexpression dose dependently reduced U87-MG cell viability and induced apoptosis through caspase-3 activation and poly(ADP ribose) polymerase degradation. A transcriptome microarray revealed 150 downregulated genes and 380 upregulated genes in miR-302b-overexpressing cells. Nuclear factor IA (NFIA), higher levels of which were significantly related to poor survival, was identified as a direct target gene of miR-302b and was involved in miR-302b-induced glioma cell death. Higher NFIA levels were observed in GBM cell lines and human tumor sections compared with astrocytes and non-tumor tissues, respectively. NFIA knockdown significantly enhanced apoptosis. We found high levels of insulin-like growth factor-binding protein 2 (IGFBP2), another miR-302b-downregulated gene, in patients with poor survival. We verified that NFIA binds to the IGFBP2 promoter and transcriptionally enhances IGFBP2 expression levels. We identified that NFIA-mediated IGFBP2 signaling pathways are involved in miR-302b-induced glioma cell death. The identification of a regulatory loop whereby miR-302b inhibits NFIA, leading to a decrease in expression of IGFBP-2, may provide novel directions for developing therapies to target glioblastoma tumorigenesis.

Exploration of inhibitory mechanisms of curcumin in lung cancer metastasis using a miRNA- transcription factor-target gene network

The present study was aimed to unravel the inhibitory mechanisms of curcumin for lung cancer metastasis via constructing a miRNA-transcription factor (TF)-target gene network. Differentially expressed miRNAs between human high-metastatic non-small cell lung cancer 95D cells treated with and without curcumin were identified using a TaqMan human miRNA array followed by real-time PCR, out of which, the top 6 miRNAs (miR-302b-3p, miR-335-5p, miR-338-3p, miR-34c-5p, miR-29c-3p and miR-34a-35p) with more verified target genes and TFs than other miRNAs as confirmed by a literature review were selected for further analysis. The miRecords database was utilized to predict the target genes of these 6 miRNAs, TFs of which were identified based on the TRANSFAC database. The findings of the above procedure were used to construct a miRNA-TF-target gene network, among which miR-34a-5p, miR-34c-5p and miR-302b-3p seemed to regulate CCND1, WNT1 and MYC to be involved in Wnt signaling pathway through the LEF1 transcription factor. Therefore, we suggest miR-34a-5p/miR-34c-5p/miR-302b-3p —LEF1—CCND1/WNT1/MYC axis may be a crucial mechanism in inhibition of lung cancer metastasis by curcumin.

The roles of microRNAs related with progression and metastasis in human cancers

Metastasis is an important factor in predicting the prognosis of the patients with cancers and contributes to high cancer-related mortality. Recent studies indicated that microRNAs (miRNAs) played a functional role in the initiation and progression of human malignancies. MicroRNAs are small non-coding RNAs of about 22 nucleotides in length that can induce messenger RNA (mRNA) degradation or repress mRNA translation by binding to the 3' untranslated region (3'-UTR) of their target genes. Overwhelming reports indicated that miRNAs could regulate cancer invasion and metastasis via epithelial-to-mesenchymal transition (EMT)-related and/or non-EMT-related mechanisms. In this review, we concentrate on the underlying mechanisms of miRNAs in regulating cancer progression and metastasis.

miR-302b regulates cell cycles by targeting CDK2 via ERK signaling pathway in gastric cancer

To investigate the molecular mechanism of miR‐302b in the regulation of cell proliferation and cell cycle regulation in gastric cancer. Samples of tumor and adjacent normal tissues were collected from 30 gastric cancer patients. Bioinformatics and the dual luciferase report were used for verification of the relationship between miR‐302b expression and cyclin‐dependent kinase 2 (CDK2). RT‐PCR and western blot were used to examine CDK2 mRNA and protein levels. The impacts of miR‐302b on CDK2 expression and extracellular signal‐regulated kinase (ERK) signaling pathway were assessed in cells transfected with miR‐302b analogs and CDK2 overexpression carrier, respectively. We used 3‐(4,5‐dimethylthiazol‐2‐yl)‐2, 5‐diphenyltetrazolium bromide (MTT) to assay gastric cancer cell growth after transfection, flow cytometry to analyze cell cycle. Compared with normal tissues, miR‐302b expression was significantly lower in gastric cancer tissues, which was significantly related to lymph node metastasis, metastasis distance, and TNM staging. miR‐302b expression was increased in miR‐302b mimics transfected cells and was significantly decreased in miR‐302b inhibitors transfected cells. CDK2 is a target gene of miR‐302b. Decreased miR‐302b and increased CDK2 expressions can significantly promote proliferation and G1/S phase transformation in gastric cancer. miR‐302b promoted the proliferation of gastric cancer cells through upregulation of CDK2, thereby inhibiting ERK pathway, which can in turn inhibit the promoting ability of miR‐302b on proliferation. The upregulation of miR‐302b reduced the expression of CDK2, and inhibited ERK signaling pathway, thereby inhibiting cell proliferation and G1/S phase conversion rate. Therefore, miR‐302b provides new perspectives for research of cell regulation and proliferation in gastric cancer, and new targets for gastric cancer diagnosis and treatment.

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.

Tumor-promoting function of single nucleotide polymorphism rs1836724 (C3388T) alters multiple potential legitimate microRNA binding sites at the 3'-untranslated region of ErbB4 in breast cancer

ErbB4 can act as either a tumor-suppressor gene or an oncogene in breast cancer. Multiple genetic factors including single nucleotide polymorphisms (SNPs) affect gene expression patterns. Multiple 3'-untranslated region (3'-UTR) SNPs reside within the target binding site of microRNAs, which can strengthen or weaken binding to target genes. The present study aimed to predict potential 3'‑UTR variants of ErbB4 that alter the target binding site of microRNAs (miRNAs) and to clarify the association of the potential variant with the risk of developing breast cancer. In silico prediction was performed to identify potential functional SNPs within miRNA target binding sites in the 3'‑UTR of ErbB4. Thus, 146 patients and controls were genotyped using restriction fragment length polymorphism-polymerase chain reaction. In addition to the Cochran-Armitage test for trend, allele and genotype frequency differences were determined to investigate the association between rs1836724 and the susceptibility to breast cancer. Bioinformatics analysis identified rs1836724 to be a polymorphism in the seed region of four miRNA binding sites (hsa-miR335-5p, hsa-miR-28-5p, has‑miR‑708‑5p and has‑miR‑665), which may participate in the development of breast cancer. Logistic regression data indicated that the T allele of the polymorphism [OR (95% CI)=1.72 (1.056‑2.808), P=0.029] is associated with the risk of breast cancer. Using bioinformatics tools, a correlation was indicated between the presence of the T allele and a reduction in ErbB4 RNA silencing based on miRNA interaction. Furthermore, case subgroup data analysis revealed an association between the C/T genotype and an ER positive phenotype [OR (95% CI)=6.00 (1.082‑33.274), P=0.028] compared with the T/T genotype. ErbB4 and estrogen receptor 1 (ESR1) are regulated by identical miRNAs thus there may be a competition for binding sites. Due to this pattern, if the interaction between miRNAs with one gene is reduced, it may be consistent with the increase in interaction with another one. Therefore, more interaction with rs1836724 C variant within ErbB4 may be associated with higher expression of ESR1 (ER‑positive phenotype). miRNAs interact with ErbB4 mRNA more frequently when it carries C allele at the rs1836724 position compared with the T carriers. Therefore, the identical miRNA interacts with ESR1 less frequently when ErbB4 mRNA has a C allele. Therefore, ESR1 expression may be higher when ErbB4 mRNA has a C allele.

miR-302b enhances breast cancer cell sensitivity to cisplatin by regulating E2F1 and the cellular DNA damage response

The identification of the molecular mechanisms involved in the establishment of the resistant phenotype represents a critical need for the development of new strategies to prevent or overcome cancer resistance to anti-neoplastic treatments.Breast cancer is the leading cause of cancer-related deaths in women, and resistance to chemotherapy negatively affects patient outcomes. Here, we investigated the potential role of miR-302b in the modulation of breast cancer cell resistance to cisplatin.miR-302b overexpression enhances sensitivity to cisplatin in breast cancer cell lines, reducing cell viability and proliferation in response to the treatment. We also identified E2F1, a master regulator of the G1/S transition, as a direct target gene of miR-302b. E2F1 transcriptionally activates ATM, the main cellular sensor of DNA damage. Through the negative regulation of E2F1, miR-302b indirectly affects ATM expression, abrogating cell-cycle progression upon cisplatin treatment. Moreover miR-302b, impairs the ability of breast cancer cells to repair damaged DNA, enhancing apoptosis activation following cisplatin treatment.These findings indicate that miR-302b plays a relevant role in breast cancer cell response to cisplatin through the modulation of the E2F1/ATM axis, representing a valid candidate as therapeutic tool to overcome chemotherapy resistance.

Noncoding RNA Expression Aberration Is Associated with Cancer Progression and Is a Potential Biomarker in Esophageal Squamous Cell Carcinoma

Esophageal cancer is one of the most common cancers worldwide. Esophageal squamous cell carcinoma (ESCC) is the major histological type of esophageal cancer in Eastern Asian countries. Several types of noncoding RNAs (ncRNAs) function as key epigenetic regulators of gene expression and are implicated in various physiological processes. Unambiguous evidence indicates that dysregulation of ncRNAs is deeply implicated in carcinogenesis, cancer progression and metastases of various cancers, including ESCC. The current review summarizes recent findings on the ncRNA-mediated mechanisms underlying the characteristic behaviors of ESCC that will help support the development of biomarkers and the design of novel therapeutic strategies.

Plasma levels of microRNA-24, microRNA-320a, and microRNA-423-5p are potential biomarkers for colorectal carcinoma

BACKGROUND

MicroRNAs are stable and easy to detect in plasma. The plasma levels of microRNAs are often changed in disease conditions, including cancer. This makes circulating microRNAs a novel class of biomarkers for cancer diagnosis. Analyses of online microRNA data base revealed that expression level of three microRNAs, microRNA-24 (miR-24), microRNA-320a (miR-320a), and microRNA-423-5p (miR-423-5p) were down-regulated in colorectal cancer (CRC). However, whether the plasma level of these three microRNAs can serve as biomarkers for CRC diagnosis and prognosis is not determined.

METHODS

Plasma samples from 223 patients with colorectal related diseases (111 cancer carcinoma, 59 adenoma, 24 colorectal polyps and 29 inflammatory bowel disease) and 130 healthy controls were collected and subjected to reverse transcription-quantitative real time PCR (RT-qPCR) analyses for the three microRNAs. In addition, plasma samples from 43 patients were collected before and after surgical treatment for the same RT-qPCR analyses.

RESULTS

The concentrations of plasma miR-24, miR-320a and miR-423-5p were all decreased in patients with CRC and benign lesions (polyps and adenoma) compared with healthy controls, but increased in inflammatory bowel disease (IBD). The sensitivity of miR-24, miR-320a and miR-423-5p for early stage of CRC were 77.78 %, 90.74 %, and 88.89 %, respectively. Moreover, the plasma concentration of the three microRNAs was increased in patients after the surgery who had clinical improvement.

CONCLUSIONS

The plasma levels of miR-24, miR-320a, and miR-423-5p have promising potential to serve as novel biomarkers for CRC detection, especially for early stage of CRC, which are superior to the currently used clinical biomarkers for CRC detection, such as CEA and CA19-9. Further efforts to develop the three microRNAs as biomarkers for early CRC diagnosis and prediction of surgical treatment outcomes are warrant.

MicroRNAs and Growth Factors: An Alliance Propelling Tumor Progression

Tumor progression requires cancer cell proliferation, migration, invasion, and attraction of blood and lymph vessels. These processes are tightly regulated by growth factors and their intracellular signaling pathways, which culminate in transcriptional programs. Hence, oncogenic mutations often capture growth factor signaling, and drugs able to intercept the underlying biochemical routes might retard cancer spread. Along with messenger RNAs, microRNAs play regulatory roles in growth factor signaling and in tumor progression. Because growth factors regulate abundance of certain microRNAs and the latter modulate the abundance of proteins necessary for growth factor signaling, the two classes of molecules form a dense web of interactions, which are dominated by a few recurring modules. We review specific examples of the alliance formed by growth factors and microRNAs and refer primarily to the epidermal growth factor (EGF) pathway. Clinical applications of the crosstalk between microRNAs and growth factors are described, including relevance to cancer therapy and to emergence of resistance to specific drugs.

miR-302b suppresses cell invasion and metastasis by directly targeting AKT2 in human hepatocellular carcinoma cells

MicroRNAs (miRNAs) have been shown to play essential roles in regulating the activity of human hepatocellular carcinoma (HCC) cells, thereby contributing to the suppression of invasion and metastasis. In this study, using gain and loss of function assays, we demonstrated that miR-302b was frequently down-regulated in clinical HCC specimens, as compared with 15 corresponding adjacent normal tissues. Overexpression of miR-302b suppressed HCC cell invasion and metastasis. Regulation of NF-κB and matrix metalloproteinase (MMP)-2 expression by miR-302b was mediated via AKT2 in SMMC-7721 cells. Silencing AKT2 produced effects similar to those of miR-302b overexpression, which included inhibiting SMMC-7721 cell invasion and metastasis and dereasing NF-κB and MMP-2 expression. Furthermore, overexpression of AKT2 attenuated the effects of miR-302b overexpression. Taken together, our findings indicate that miR-302b inhibits SMMC-7721 cell invasion and metastasis by targeting AKT2, suggesting that miR-302b might represent a potential therapeutic target for HCC intervention.

MiR-96 promotes proliferation and chemo- or radioresistance by down-regulating RECK in esophageal cancer

The involvement of miR-96 in esophageal cancer (EC) remains unclear. The aim of this study is to explore the functional role of miR-96 and determine whether miR-96 could be a potential therapeutic target for human esophageal cancer. MiR-96 up-regulation was demonstrated in 145 EC samples and RECK down-regulation was validated in EC cell lines. Moreover, ectopic overexpression of miR-96 in TE-1 or ECa-109 contributed to tumor growth in xenograft mouse models. Furthermore, up-regulation of miR-96 could reduce the susceptibilities of EC cells to chemotherapy or radiotherapy. RECK was identified as a target of miR-96 and RECK overexpressing could abrogate the growth of EC cells induced by miR-96. Taken together, miR-96 serves as an oncogene role in EC cells through downregulating RECK.

miR-101 suppresses tumor proliferation and migration, and induces apoptosis by targeting EZH2 in esophageal cancer cells

AIM

To investigate the role of miR-101 in the regulation of tumor proliferation, invasion, apoptosis and to its target gene in human ESCC.

METHODS

The expression level of miR-101 in Eca109 cell line was determined by real-time polymerase chain reaction (PCR). After transfected with miR-101 mimics and inhibitor, proliferation, migration and apoptosis in ESCC cell line (Eca109) were detected by MTT, cell wound healing assay and flow cytometry, respectively. The expression of EZH2 in Eca109 cell was examined by immunohistochemical staining.

RESULTS

We found that miR-101 was significantly down-regulated in ESCC cell than in matched normal esophageal epithelium cell. The expression level of miR-101 was inversely correlated to EZH2 protein expression in ESCC cell. In Eca109 cells, over-expression of miR-101 significantly inhibited the migration and invasion of ESCC cells, and promotes cell apoptosis.

CONCLUSIONS

These findings suggest that decreased expression of miR-101 might promote metastasis of human ESCC by inducing accumulation of EZH2 protein.

MicroRNA-320c inhibits tumorous behaviors of bladder cancer by targeting Cyclin-dependent kinase 6

Background

Increasing evidence has suggested that dysregulation of microRNAs (miRNAs) could contribute to human disease including cancer. Previous miRNA microarray analysis illustrated that miR-320c is down-regulated in various cancers. However, the roles of miR-320c in human bladder cancer have not been well elucidated. Therefore, this study was performed to investigate the biological functions and molecular mechanisms of miR-320c in human bladder cancer cell lines, discussing whether it could be a therapeutic biomarker of bladder cancer in the future.

Methods

Two human bladder cancer cell lines and samples from thirteen patients with bladder cancer were analyzed for the expression of miR-320c by quantitative RT-PCR. Over-expression of miR-320c was established by transfecting mimics into T24 and UM-UC-3. Cell proliferation and cell cycle were assessed by cell viability assay, flow cytometry and colony formation assay. Cell motility ability was evaluated by transwell assay. The target gene of miR-320c was determined by luciferase assay, quantitative RT-PCR and western blot. The regulation of cell cycle and mobility by miR-320c was analyzed by western blot.

Results

We observed that miR-320c was down-regulated in human bladder cancer tissues and bladder cancer cell lines T24 and UM-UC-3. Over-expression of miR-320c could induce G1 phase arrest in UM-UC-3 and T24 cells, and subsequently inhibited cell growth. We also indentified miR-320c could impair UM-UC-3 and T24 cell motility. In addition, we identified CDK6, a cell cycle regulator, as a novel target of miR-320c. Moreover, we demonstrated miR-320c could induce bladder cancer cell cycle arrest and mobility via regulating CDK6. We also observed that inhibition of miR-320c or restoration of CDK6 in miR-320c-over-expressed bladder cancer cells partly reversed the suppressive effects of miR-320c.

Conclusions

miR-320c could inhibit the proliferation, migration and invasion of bladder cancer cells via regulating CDK6. Our study revealed that miR-320c could be a therapeutic biomarker of bladder cancer in the future.