MiR-200a enhances the migrations of A549 and SK-MES-1 cells by regulating the expression of TSPAN1

Paradigm shift: microRNAs interact with target gene promoters to cause transcriptional gene activation or silencing

MicroRNAs (miRNAs/miRs) are small (18-25 nucleotides in length), endogenous, non-coding RNAs that typically repress gene expression by interacting with the 3'untranslated regions (3'UTRs) of target mRNAs in the cytoplasm. While most of the scientific community still views miRNAs as repressors of gene expression, this review highlights their non-canonical novel role in the nucleus as activators or silencers of target gene transcription through miRNA-promoter interaction. The mechanistic details of the transcriptional role of miRNAs are yet to be elucidated, however, they can be explained by prospective models. In this review, we aim to discuss the different examples of transcriptional regulation by miRNAs and their possible mechanism of action, thereby offering a comprehensive perspective on the role of miRNAs in gene regulation and their importance in health and diseases.

Using a human bronchial epithelial cell-based malignant transformation model to explore the function of hsa-miR-200 family in the progress of PM2.5-induced lung cancer development

Numerous studies have revealed that ambient long-term exposure to fine particulate matter (PM_2.5) is significantly related to the development of lung cancer, but the molecular mechanisms of PM_2.5 exposure-induced lung cancer remains unknown. As an important epigenetic regulator, microRNAs (miRNAs) play vital roles in responding to environment exposure and various diseases including lung cancer development. Here we constructed a PM_2.5-induced malignant transformed cell model and found that miR-200 family, especially miR-200a-3p, was involved in the process of PM_2.5 induced lung cancer. Further investigation of the function of miR-200 family (miR-200a-3p as a representative revealed that miR-200a-3p promoted cell migration by directly suppressing TNS3 expression. These results suggested that ambient PM_2.5 exposure may increase the expression of miR-200 family and then promote the proliferation and migration of lung cancer cells. Our study provided novel model and insights into the molecular mechanism of ambient PM_2.5 exposure-induced lung cancer.

The role of miR-200 family in the regulation of hallmarks of cancer

MiRNAs are short non-coding RNAs that regulate gene expression post-transcriptionally contributing to the development of different diseases including cancer. The miR-200 family consists of five members, miR-200a, miR-200b, miR-200c, miR-141, and miR-429. Their expression is dysregulated in cancer tissue and their level is altered in the body fluids of cancer patients. Moreover, the levels of miR-200 family members correlate with clinical parameters such as cancer patients' survival which makes them potentially useful as diagnostic and prognostic biomarkers. MiRNAs can act as either oncomiRs or tumor suppressor miRNAs depending on the target genes and their role in the regulation of key oncogenic signaling pathways. In most types of cancer, the miR-200 family acts as tumor suppressor miRNA and regulates all features of cancer. In this review, we summarized the expression pattern of the miR-200 family in different types of cancer and their potential utility as biomarkers. Moreover, we comprehensively described the role of miR-200 family members in the regulation of all hallmarks of cancer proposed by Hanahan and Weinberg with the focus on the epithelial-mesenchymal transition, invasiveness, and metastasis of tumor cells.

MicroRNA‑200a‑3p and GATA6 are abnormally expressed in patients with non‑small cell lung cancer and exhibit high clinical diagnostic efficacy

Lung cancer is one of the main threats to human health. Survival of patients with lung cancer depends on timely detection and diagnosis. Among the genetic irregularities that control cancer development and progression, there are microRNAs (miRNAs/miRs). The present study aimed to investigate the expression patterns of miR-200a-3p and transcription factor GATA-6 (GATA6) in peripheral blood of patients with non-small cell lung cancer (NSCLC) and their clinical significance. The expression patterns of miR-200a-3p and GATA6 in the peripheral blood of patients with NSCLC and healthy subjects were measured via reverse transcription-quantitative PCR. The correlation between GATA6/miR-200a-3p expression and their diagnostic efficacy were analyzed by receiver operating characteristic curve analysis. The association between miR-200a-3p/GATA6 expression with the patient clinicopathological characteristics, and their correlation with carcinoembryonic antigen (CEA), neuron specific enolase (NSE) and squamous cell carcinoma antigen (SCCAg) were evaluated. The cumulative survival rate was examined, and whether miR-200a-3p and GATA6 expression levels were independently correlated with the prognosis of NSCLC was analyzed using multivariate logistic regression model. The results demonstrated that the expression of miR-200a-3p was high and that of GATA6 was low in the peripheral blood of patients with NSCLC, and both exhibited high clinical diagnostic efficacy. miR-200a-3p was revealed to target GATA6 by dual-luciferase assay. miR-200a-3p in the peripheral blood was correlated with TNM stage, lymph node metastasis and distal metastasis, while GATA6 in the peripheral blood was correlated with TNM stage and lymph node metastasis. miR-200a-3p and GATA6 were positively correlated with CEA and SCCAg, but not with NSE. High expression of miR-200a-3p and low expression of GATA6 predicted poor prognosis in patients with NSCLC. After adjusting for TNM stage, lymph node metastasis, distance metastasis, GATA6, CEA, NSE and SCCAg in the logistic regression model, it was indicated that the high expression of miR-200a-3p increased the risk of death in patients with NSCLC. Collectively, it was revealed that miR-200a-3p and GATA6 were abnormally expressed in the peripheral blood of patients with NSCLC. Serum levels of miR-200a-3p >1.475 and GATA6 <1.195 may assist the early diagnosis of NSCLC. GATA6 may function in NSCLC as a miR-200a-3p target, which may provide a future reference for NSCLC early diagnosis and treatment.

TSPAN1, a novel tetraspanin member highly involved in carcinogenesis and chemoresistance

The tetraspanin (TSPAN) family constitutes a poorly explored family of membrane receptors involved in various physiological processes, with relevant roles in anchoring multiple proteins, acting as scaffolding proteins, and cell signaling. Recent studies have increasingly demonstrated the involvement of TSPANs in cancer. In particular, tetraspanin 1 (also known as TSPAN1, NET-1, TM4C, C4.8 or GEF) has been implicated in cell survival, proliferation and invasion. Recently, our laboratory revealed a key role of TSPAN1 in the acquired resistance of tumor cells to conventional chemotherapy (e.g., cisplatin). In this review, we summarize and discuss the latest research on the physiological mechanisms of TSPANs in cancer and, in particular, on TSPAN1 regulating resistance to chemotherapy. A model of TSPAN1 action is proposed, and the potential of targeting TSPAN1 in anticancer therapeutic strategies is discussed.

The ellagic acid metabolites urolithin A and B differentially affect growth, adhesion, motility, and invasion of endometriotic cells in vitro

STUDY QUESTION

What are the effects of plant-derived antioxidant compounds urolithin A (UA) and B (UB) on the growth and pathogenetic properties of an in vitro endometriosis model?

SUMMARY ANSWER

Both urolithins showed inhibitory effects on cell behavior related to the development of endometriosis by differentially affecting growth, adhesion, motility, and invasion of endometriotic cells in vitro.

WHAT IS KNOWN ALREADY

Endometriosis is one of the most common benign gynecological diseases in women of reproductive age and is defined by the presence of endometrial tissue outside the uterine cavity. As current pharmacological therapies are associated with side effects interfering with fertility, we aimed at finding alternative therapeutics using natural compounds that can be administered for prolonged periods with a favorable side effects profile.

STUDY DESIGN, SIZE, DURATION

In vitro cultures of primary endometriotic stromal cells from 6 patients subjected to laparoscopy for benign pathologies with histologically confirmed endometriosis; and immortalized endometrial stromal (St-T1b) and endometriotic epithelial cells (12Z) were utilized to assess the effects of UA and UB on endometriotic cell properties. Results were validated in three-dimensional (3D) in vitro co-culture spheroids of 12Z and primary endometriotic stroma cells of one patient, and organoids from 3 independent donors with endometriosis.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The effects on cell growth were measured by non-radioactive colorimetric assay to measure cellular metabolic activity as an indicator of cell viability (MTT assay) and flow cytometric cell cycle assay on primary cultures, St-T1b, and 12Z. Apoptosis analyses, the impact on in vitro adhesion, migration, and invasion were evaluated in the cell lines. Moreover, Real-Time Quantitative Reverse Transcription polymerase chain reaction (RT-qPCR) assays were performed on primary cultures, St- T1b and 12Z to evaluate a plausible mechanistic contribution by factors related to proteolysis (matrix metalloproteinase 2, 3 and 9 -MMP2, MMP3, MMP9-, and tissue inhibitor of metalloproteinases -TIMP-1-), cytoskeletal regulators (Ras-related C3 botulinum toxin substrate 1 -RAC1-, Rho-associated coiled-coil containing protein kinase 2 -ROCK2-), and cell adhesion molecules (Syndecan 1 -SDC1-, Integrin alpha V-ITGAV-). Finally, the urolithins effects were evaluated on spheroids and organoids by formation, viability, and drug screen assays.

MAIN RESULTS AND THE ROLE OF CHANCE

40 µM UA and 20 µM UB produced a significant decrease in cell proliferation in the primary endometriotic cell cultures (P < 0.001 and P < 0.01, respectively) and in the St-T1b cell line (P < 0.001 and P < 0.05, respectively). In St-T1b, UA exhibited a mean half-maximum inhibitory concentration (IC50) of 39.88 µM, while UB exhibited a mean IC50 of 79.92 µM. Both 40 µM UA and 20 µM UB produced an increase in cells in the S phase of the cell cycle (P < 0.01 and P < 0.05, respectively). The same concentration of UA also increased the percentage of apoptotic ST-t1b cells (P < 0.05), while both urolithins decreased cell migration after 24 h (P < 0.001 both). Only the addition of 5 µM UB decreased the number of St-T1b adherent cells. TIMP-1 expression was upregulated in response to treating the cells with 40 µM UA (P < 0.05). Regarding the 12Z endometriotic cell line, only 40 µM UA decreased proliferation (P < 0.01); while both 40 µM UA and 20 µM UB produced an increase in cells in the G2/M phase (P < 0.05 and P < 0.01, respectively). In this cell line, UA exhibited a mean IC50 of 40.46 µM, while UB exhibited a mean IC50 of 54.79 µM. UB decreased cell migration (P < 0.05), and decreased the number of adherent cells (P < 0.05). Both 40 µM UA and 20 µM UB significantly decreased the cellular invasion of these cells; and several genes were altered when treating the cells with 40 µM UA and 10 µM UB. The expression of MMP2 was downregulated by UA (P < 0.001), and expression of MMP3 (UA P < 0.001 and UB P < 0.05) and MMP9 (P < 0.05, both) were downregulated by both urolithins. Moreover, UA significantly downregulated ROCK2 (P < 0.05), whereas UB treatment was associated with RAC1 downregulation (P < 0.05). Finally, the matrix adhesion receptors and signaling (co)receptors SDC1 and ITGAV were downregulated upon treatment with either UA or UB (P < 0.01 and P < 0.05, respectively in both cases). Regarding the effects of urolithins on 3D models, we have seen that they significantly decrease the viability of endometriosis spheroids (80 µM UA and UB: P < 0.05 both) as well as affecting their area (40 µM UA: P < 0.05, and 80 µM UA: P < 0.01) and integrity (40 µM UA and UB: P < 0.05, 80 µM UA and UB: P < 0.01). On the other hand, UA and UB significantly inhibited organoid development/outgrowth (40 and 80 µM UA: P < 0.0001 both; 40 µM UB: P < ns-0.05-0.001, and 80 µM UB: P < 0.01-0.001-0.001), and all organoid lines show urolithins sensitivity resulting in decreasing viability (UA exhibited a mean IC50 of 33.93 µM, while UB exhibited a mean IC50 of 52.60 µM).

LARGE-SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

This study was performed on in vitro endometriosis models.

WIDER IMPLICATIONS OF THE FINDINGS

These in vitro results provide new insights into the pathogenetic pathways affected by these compounds and mark their use as a potential new therapeutic strategy for the treatment of endometriosis.

STUDY FUNDING/COMPETING INTEREST(S)

This study was funded EU MSCA-RISE-2015 project MOMENDO (691058). The authors have no conflicts of interest to declare.

miRNA-200a Regulating Proliferation, Migration, and Infiltration of Tongue Squamous Cell Carcinoma Cells by Targeting DEK Proto-Oncogene

Tongue squamous cell carcinoma (TSCC) is the most frequently occurring oral cancer and is characterized by high proliferation and metastasis rates. Incomplete understanding of the pathogenesis of TSCC coupled with frequent tongue movement increases the difficulty of therapy. Additionally, TSCC is prone to recurrence and metastasis after treatment. Thus, exploring mechanisms of proliferation, migration, and infiltration of TSCC cancer cells is essential for reducing morbidity and mortality. Transfection of miRNA-200a mimics into SCC15 cells showed that miRNA-200a expression decreased significantly, and DEK expression significantly increased. Transfection of miRNA-200a mimics (miRNA-200a group), negative control mimics (miRNA-NC group), empty vector (miRNA-200a + pcDNA3.1 group), and miRNA-200a mimics and DEK overexpression vector (miRNA-200a + DEK group) into SCC15 cells respectively indicates that overexpression of miRNA-200a substantially inhibits SCC15 cell proliferation, infiltration and migration, decreases PCNA and Vimentin expression, and promotes E-cadherin expression. miRNA-200a + DEK transfection induced greater cell proliferation, infiltration and migration, much higher PCNA and Vimentin expression, and significantly lower E-cadherin expression. Luciferase reporter gene detection of overexpressed DEK or DEK expression after inhibiting miRNA-200a expression indicated a targeting association between miRNA-200a and DEK. miRNA-200a inhibits proliferation, infiltration and migration ability of TSCC by targeting DEK and may represent a novel means for clinical intervention in TSCC. miRNA-200a inhibits proliferation, invasion, and migration of TSCC by targeting DEK.

miR-200a contributes to the migration of BMSCs induced by the secretions of E. faecalis via FOXJ1/NFκB/MMPs axis

Background

Upon migrating to the injured sites, bone marrow mesenchymal stem cells (BMSCs) play critical roles in the repair of bone lesion caused by chronic apical periodontitis. Emerging evidences have shown that Enterococcus faecalis is always associated with apical periodontitis, especially refractory apical periodontitis. But the mechanism underlying how Enterococcus faecalis affects the migration of BMSCs remains unclear.

Methods

The effects of Enterococcus faecalis supernatants on the migration of BMSCs were determined by transwell migration assays. miRNA sequencing was performed to detect the significantly differentially expressed miRNAs of BMSCs. Proteomics analysis was used to detect the protein expression alterations of BMSCs. Luciferase report assays were deployed to verify the targets of miRNA. Western blot analysis was performed to examine the expressions of matrix metalloproteinases-3, matrix metalloproteinases-9, Forkhead Box Protein J1 (FOXJ1), and nuclear factor kappa B (NFκB). The activations of NFκB were detected by luciferase assays with NFκBluc reporter.

Results

We found that Enterococcus faecalis supernatants could promote the migration of BMSCs. The upregulation of miR-200a-3p in this process contributed to BMSC migration through downregulating its target Forkhead Box Protein J1. Moreover, FOXJ1/ NFκB axis was found to regulate matrix metalloproteinases (MMPs) in this process.

Conclusions

These results above suggest that miR-200a contributes to the migration of BMSCs induced by the secretions of E. faecalis via FOXJ1/NFκB/MMPs axis.

LncRNA FTX activates FOXA2 expression to inhibit non-small-cell lung cancer proliferation and metastasis

Lung cancer leads to the highest mortality among all cancer types in the world, and non–small‐cell lung cancer (NSCLC) occupies over 80% of the lung cancer cases. Numerous studies have demonstrated that long non‐coding RNA (lncRNA) is involved in various human diseases including cancer. LncRNA FTX was firstly identified in Xist gene locus and was dysregulated in many human cancers. However, the function of FTX in NSCLC is still unclear. Here, we report that long non‐coding RNA FTX expression level is down‐regulated in NSCLC clinical tissue samples and cell lines. Ectopic expression of FTX inhibits proliferation and metastasis of lung cancer cells in vitro and in vivo. Furthermore, we find that FTX overexpression activates the expression of transcription factor FOXA2, an important regulator in lung cancer progression, and we reveal a novel FTX/miR‐200a‐3p/FOXA2 competing endogenous RNA regulatory axis in lung cancer cells. Our results provide new insights and directions for exploring the function of FTX in lung cancer progression.

Potential use of ellagic acid for endometriosis treatment: its effect on a human endometrial cell cycle, adhesion and migration

EA treatment decreases cell adhesion and migration of endometrial cells and alters the progression of an endometrial stromal cell line cycle.

Neuroprotective effects of overexpressed microRNA-200a on activation of glaucoma-related retinal glial cells and apoptosis of ganglion cells via downregulating FGF7-mediated MAPK signaling pathway

Glaucoma is a progressive optic neuropathy and is one of the leading causes of blindness in the industrialized countries. The involvement of microRNAs (miRs) has been implicated in regulating the complex biological responses to changes in intraocular pressure. However, the therapeutic role of miR-200a on glaucoma has not been well studied yet. In this study, we confirmed the role of miR-200a in glaucoma progression and identified the related mechanism. Microarray expression profiles were used to screen the glaucoma-related genes. The relationship between miR-200a and FGF7 was validated by bioinformatics analysis and dual-luciferase reporter gene assay. Glaucoma-related parameters including the expression of CD11b and iNOS, activation of Muller cells, and apoptosis of retinal ganglion cells (RGCs) in the mouse model were measured by immunohistochemistry, MTT assay and TUNEL assay, respectively. miR-200a was reduced in glaucoma, whereas FGF7 was robustly induced. Thereby, we speculated that FGF7 was negatively regulated by miR-200a. Downregulated miR-200a could activate the MAPK signaling pathway following elevations in ERK, JNK, p38 and Bax expression and reduction in Bcl-2 expression. In the mouse model, downregulated miR-200a increased the expression of CD11b and iNOS and the apoptosis of RGCs, but stimulated the inactivation of Muller cells. However, the above-mentioned alternations induced by downregulated miR-200a were reversed after FGF7 repression. miR-200a can inhibit the FGF7-mediated MAPK signaling pathway and play a protective role on improving the glaucoma-induced optical nerve injury.

MiRNA-200a expression is inverse correlation with hepatocyte growth factor expression in stromal fibroblasts and its high expression predicts a good prognosis in patients with non-small cell lung cancer

Cancer-associated fibroblasts (CAFs) play an important role in favoring tumor progression. However, little is known concerning expression of miRNA-200a and its potential target gene hepatocyte growth factor (HGF) in CAFs. In the present study, we investigated expression levels and prognostic significance of miRNA-200a and HGF in stromal fibroblasts of non-small cell lung cancer (NSCLC), and evaluated the correlation between miRNA-200a and HGF. In situ hybridization and immunohistochemical staining were used to investigate expression levels of miRNA-200a and HGF in 134 formalin-fixed paraffin-embedded tumor specimens from clinical stage I -IIIA NSCLC, respectively. The results showed a significant inverse correlation existed between miRNA-200a and HGF expression level in stromal fibroblasts (χ² = 21.778, p = 0.000). In vitro, the upregulation of miRNA-200a reduced expression of HGF protein in human CAFs. The 3-year overall survival (OS) rates with low and high miRNA-200a expression in stromal fibroblasts were 39.0% and 53.4%, respectively (χ²=4.25, p=0.039). The 3-year OS rates with low and high HGF expression in stromal fibroblasts were 60.3% and 31.8%, respectively (χ²=12.55, p=0.000). The multivariate analysis showed that clinical stage and HGF expression level in stromal fibroblasts were the independent predictive factors of OS. These results suggested that miRNA-200a expression was inverse correlation with HGF expression in stromal fibroblasts. High miRNA-200a and low HGF expression in stromal fibroblasts may predict a good prognosis in patients with NSCLC.

Osteoactivin (GPNMB) ectodomain protein promotes growth and invasive behavior of human lung cancer cells

The potential application of GPNMB/OA as a therapeutic target for lung cancer will require a greater understanding of the impact of GPNMB/OA ectodomain (ECD) protein shedding into tumor tissues. Thus, in this work we characterized GPNMB/OA expression and extent of shedding of its ECD protein while evaluating the impact on lung cancer progression using three non-small cell lung cancer (NSCLC) cell lines: A549, SK-MES-1 and calu-6. We observed a direct correlation (R² = 0.89) between GPNMB/OA expression on NSCLC cells and the extent of GPNMB/OA ECD protein shedding. Meanwhile, siRNA-mediated knockdown of GPNMB/OA in cancer cells significantly reduced GPNMB/OA ECD protein shedding, migration, invasion and adhesion to extracellular matrix materials. Also, exogenous treatment of cancer cells (expressing low GPNMB/OA) with recombinant GPNMB/OA protein (rOA) significantly facilitated cell invasion and migration, but the effects of rOA was negated by inclusion of a selective RGD peptide. Further studies in athymic (nu/nu) mice-bearing calu-6 showed that intratumoral supplementation with rOA effectively facilitated in vivo tumor growth as characterized by a high number of proliferating cells (Ki67 staining) coupled with a low number of apoptotic cells. Taken together, our results accentuate the relevance of GPNMB/OA ECD protein shedding to progression of lung cancer. Thus, strategies that suppress GPNMB/OA expression on lung cancer cells as well as negate shedding of GPNMB/OA ECD protein are worthy of consideration in lung cancer therapeutics.

Expression and function of tetraspanin 1 in esophageal carcinoma

The present study explored the expression of tetraspanin 1 (TSPAN1) in esophageal carcinoma (EC) and its association with clinicopathological factors. TSPAN1 small interfering RNA (siRNA) was designed to target the TSPAN1 gene in Eca-109 cells in order to explore the biological function of TSPAN1 in the proliferation and apoptosis of EC. The results demonstrated that the level of TSPAN1 expression in EC tissue was significantly increased compared with that in adjacent normal tissue (P<0.001). TSPAN1 expression was also associated with histological differentiation, depth of invasion, lymph node metastasis (all P<0.05) and Ki-67 (P<0.01). However, no association was observed between TSPAN expression and gender, age or location (P>0.05). In addition, silencing TSPAN1 markedly inhibited proliferation while increasing the apoptosis rate of Eca-109 cells, which was demonstrated by detecting the expression of the cell proliferation-associated gene Ki-67 and the apoptotic gene caspase-3 (P<0.05). Taken together, these results indicated that TSPAN1 functions as a tumor-associated gene in EC through promoting cell proliferation and suppressing apoptosis, and siRNA technology may provide an advanced alternative in the development of therapeutics for EC.

The cancer-associated cell migration protein TSPAN1 is under control of androgens and its upregulation increases prostate cancer cell migration

Cell migration drives cell invasion and metastatic progression in prostate cancer and is a major cause of mortality and morbidity. However the mechanisms driving cell migration in prostate cancer patients are not fully understood. We previously identified the cancer-associated cell migration protein Tetraspanin 1 (TSPAN1) as a clinically relevant androgen regulated target in prostate cancer. Here we find that TSPAN1 is acutely induced by androgens, and is significantly upregulated in prostate cancer relative to both normal prostate tissue and benign prostate hyperplasia (BPH). We also show for the first time, that TSPAN1 expression in prostate cancer cells controls the expression of key proteins involved in cell migration. Stable upregulation of TSPAN1 in both DU145 and PC3 cells significantly increased cell migration and induced the expression of the mesenchymal markers SLUG and ARF6. Our data suggest TSPAN1 is an androgen-driven contributor to cell survival and motility in prostate cancer.

microRNA-200a-3p increases 5-fluorouracil resistance by regulating dual specificity phosphatase 6 expression

Acquisition of resistance to anti-cancer drugs is a significant obstacle to effective cancer treatment. Although several efforts have been made to overcome drug resistance in cancer cells, the detailed mechanisms have not been fully elucidated. Here, we investigated whether microRNAs (miRNAs) function as pivotal regulators in the acquisition of anti-cancer drug resistance to 5-fluorouracil (5-FU). A survey using a lentivirus library containing 572 precursor miRNAs revealed that five miRNAs promoted cell survival after 5-FU treatment in human hepatocellular carcinoma Hep3B cells. Among the five different clones, the clone expressing miR-200a-3p (Hep3B-miR-200a-3p) was further characterized as a 5-FU-resistant cell line. The cell viability and growth rate of Hep3B-miR-200a-3p cells were higher than those of control cells after 5-FU treatment. Ectopic expression of a miR-200a-3p mimic increased, while inhibition of miR-200a-3p downregulated, cell viability in response to 5-FU, doxorubicin, and CDDP (cisplatin). We also showed that dual-specificity phosphatase 6 (DUSP6) is a novel target of miR-200a-3p and regulates resistance to 5-FU. Ectopic expression of DUSP6 mitigated the pro-survival effects of miR-200a-3p. Taken together, these results lead us to propose that miR-200a-3p enhances anti-cancer drug resistance by decreasing DUSP6 expression.

Tetraspanin 1 is involved in survival, proliferation and carcinogenesis of pancreatic cancer

Pancreatic cancer (PCC) is one of the most difficult cancers to treat and the 10th leading cause of cancer-related death in worldwide. Studies have demonstrated that the tetraspanin 1 (Tspan1) is overexpressed in various cancers and may be a potential therapeutic strategy for the treatment of different cancers. However, the possible role of Tspan1 in PCC is still unknown. In the present study, our data revealed that the increased Tspan1 in PCC tissues was associated with the clinicopathological features and survival rate of PCC patient. We also investigated the effects of Tspan1 gene knockdown on the biological behavior of human PCC. The expression of Tspan1 (detected by immunohistochemistry, qRT-PCR and western blot analysis) derived from human PCC tissues and cell lines (AsPC-1 and PANC-1), were significantly elevated compared with those of the control (P<0.05). Transfection with siRNA-targeting Tspan1 significantly decreased proliferation, increased the apoptosis and reduced migration and invasion of AsPC-1 and PANC-1 cells. The present study demonstrated that Tspan1 plays an important role in PCC carcinogenic progression, including migration and invasion. The siRNA targeting of Tspan1 may be a potential therapeutic strategy for the treatment of PCC.

Genome-wide analysis of enhancer RNA in gene regulation across 12 mouse tissues

Enhancers play a crucial role in gene regulation but the participation of enhancer transcripts (i.e. enhancer RNA, eRNAs) in regulatory systems remains unclear. We provide a computational analysis on eRNAs using genome-wide data across 12 mouse tissues. The expression of genes targeted by transcribing enhancer is positively correlated with eRNA expression and significantly higher than expression of genes targeted by non-transcribing enhancers. This result implies eRNA transcription indicates a state of enhancer that further increases gene expression. This state of enhancer is tissue-specific, as the same enhancer differentially transcribes eRNAs across tissues. Therefore, the presence of eRNAs describes a tissue-specific state of enhancer that is generally associated with higher expressed target genes, surmising as to whether eRNAs have gene activation potential. We further found a large number of eRNAs contain regions in which sequences and secondary structures are similar to microRNAs. Interestingly, an increasing number of recent studies hypothesize that microRNAs may switch from their general repressive role to an activating role when targeting promoter sequences. Collectively, our results provide speculation that eRNAs may be associated with the selective activation of enhancer target genes.

Mechanisms behind the inhibition of lung adenocarcinoma cell by shikonin

Shikonin, a natural naphthoquinone isolated from a traditional Chinese medicinal herb, can exert inhibitory effect on tumor cell growth. However, little has been known concerning the effect of shikonin on lung adenocarcinoma cell and underlying mechanisms. In the present study, we investigated the effect of shikonin on the proliferation, cell cycle arrest, and apoptosis in human lung adenocarcinoma cells. We found that shikonin significantly suppressed the proliferation of lung adenocarcinoma cells compared with control in dose- and time-dependent manner (P < 0.05). In the meantime, our results showed that shikonin markedly increased the proportion of A549 cells at stage G1 as well as induced apoptosis in A549 cells. Furthermore, suppressed CCND1 and elevated caspase3 and caspase7 expression levels at mRNA were found in this study, indicating that shikonin may inhibit the growth of lung adenocarcinoma cell by changing cell cycle and promoting cell apoptosis through the regulation of CCND1, caspase3, and caspase7. Although more studies are needed, this study suggests that shikonin has the potential to be used as an anti-cancer agent in the treatment of lung adenocarcinoma.

Tetraspanins in cell migration

Tetraspanins are a superfamily of small transmembrane proteins that are expressed in almost all eukaryotic cells. Through interacting with one another and with other membrane and intracellular proteins, tetraspanins regulate a wide range of proteins such as integrins, cell surface receptors, and signaling molecules, and thereby engage in diverse cellular processes ranging from cell adhesion and migration to proliferation and differentiation. In particular, tetraspanins modulate the function of proteins involved in all determining factors of cell migration including cell-cell adhesion, cell-ECM adhesion, cytoskeletal protrusion/contraction, and proteolytic ECM remodeling. We herein provide a brief overview of collective in vitro and in vivo studies of tetraspanins to illustrate their regulatory functions in the migration and trafficking of cancer cells, vascular endothelial cells, skin cells (keratinocytes and fibroblasts), and leukocytes. We also discuss the involvement of tetraspanins in various pathologic and remedial processes that rely on cell migration and their potential value as targets for therapeutic intervention.

TSPAN1 functions as an oncogene in gastric cancer and is downregulated by miR-573

Tetraspanin 1 (TSPAN1) has been reported to be upregulated in gastric cancer (GC). However, whilst TSPAN1 is positively correlated with clinical stage and negatively correlated with survival rates, its function in GC remains elusive. Here we show that expression of TSPAN1 is significantly higher in GC tissues compared to non-cancerous tissues. Furthermore, we demonstrate that RNAi-mediated down-regulation of TSPAN1 expression markedly blocks GC cell proliferation, cell cycle progression and invasive activity. We identified TSPAN1 as a novel target gene of miR-573. Overexpression of miR-573 suppressed proliferation and invasion of GC cells by down-regulation of TSPAN1 expression. Restoration of TSPAN1 rescued the effects of miR-573 overexpression. Therefore, our findings suggest that the miR-573/TSPAN1 axis is important in the control of gastric carcinogenesis.

miR-148b reverses cisplatin-resistance in non-small cell cancer cells via negatively regulating DNA (cytosine-5)-methyltransferase 1(DNMT1) expression

Background

The emergence of drug resistance in cancer patients limits the success rate of clinical chemotherapy. MicroRNAs (miRNAs) may play a role in chemoresistance and may be involved in modulating of some drug resistance-related pathways in cancer cells. In this study, the involvement of microRNA-148b (miR-148b) and its roles in the development of chemoresistance in lung cancer are determined.

Methods

This study was performed in two lung cancer cell lines (A549 and SPC-A1). The levels of miR-148b and DNMT1 mRNA expression were determined by using Quantitative Real-Time PCR. Proteins of DNMTs are represented by western blot assay. Cell viability was assessed by MTT assay. Cell apoptosis was evaluated using flow cytometry.

Results

The data showed a down-regulated of miR-148b expression and evaluated methyltransferases (DNMTs) expression in cisplatin-resisted human non-small cell lung cancer (NSCLC) cell line-A549/DDP and SPC-A1/DDP compared with their parental A549 and SPC-A1 cell line. In transfection experiments, miR-148b mimics reduced the DNMT1 expression, as well as enhanced the sensitivity of cells to cisplatin and cisplatin-induced apoptosis in A549/DDP or SPC-A1/DDP cells. While miR-148b inhibitor increased DNMT1 expression, as well as attenuated the sensitivity of cells to cisplatin in A549 and SPC-A1 cells. miR-148b was showed to exert negative effect on DNMT1 expression by targeting its 3′UTR in A549/DDP and A549 cells. Importantly, silenced DNMT1 increases cisplatin sensitivity of A549/DDP cells and over-expressed DNMT1 reverses pro-apoptosis effect of miR-148b mimic.

Conclusions

miR-148b reverses cisplatin-resistance in non-small cell cancer cells via negatively regulating DNMT1 expression.

MiR-96 downregulates RECK to promote growth and motility of non-small cell lung cancer cells

MicroRNAs play critical roles in the development and progression of non-small cell lung cancer (NSCLC). miR-96 acts as an oncogene in some malignancies, while its role in NSCLC is unclear. Here, we validated that miR-96 was significantly increased in both human NSCLC tissues and cell lines. Inhibition of miR-96 expression remarkably reduced cell proliferation, colony formation, migration, and invasion of NSCLC cells. Reversion-inducing-cysteine-rich protein with kazal motifs (RECK) was identified as a target of miR-96 in NSCLC cells. In addition, the expression of RECK was found to be negatively correlated with the expression of miR-96 in NSCLC tissues. Our data suggest that miR-96 might promote the growth and motility of NSCLC cells partially by targeting RECK.

Differentially expressed wound healing-related microRNAs in the human diabetic cornea

MicroRNAs are powerful gene expression regulators, but their corneal repertoire and potential changes in corneal diseases remain unknown. Our purpose was to identify miRNAs altered in the human diabetic cornea by microarray analysis, and to examine their effects on wound healing in cultured telomerase-immortalized human corneal epithelial cells (HCEC) in vitro. Total RNA was extracted from age-matched human autopsy normal (n=6) and diabetic (n=6) central corneas, Flash Tag end-labeled, and hybridized to Affymetrix® GeneChip® miRNA Arrays. Select miRNAs associated with diabetic cornea were validated by quantitative RT-PCR (Q-PCR) and by in situ hybridization (ISH) in independent samples. HCEC were transfected with human pre-miR™miRNA precursors (h-miR) or their inhibitors (antagomirs) using Lipofectamine 2000. Confluent transfected cultures were scratch-wounded with P200 pipette tip. Wound closure was monitored by digital photography. Expression of signaling proteins was detected by immunostaining and Western blot. Using microarrays, 29 miRNAs were identified as differentially expressed in diabetic samples. Two miRNA candidates showing the highest fold increased in expression in the diabetic cornea were confirmed by Q-PCR and further characterized. HCEC transfection with h-miR-146a or h-miR-424 significantly retarded wound closure, but their respective antagomirs significantly enhanced wound healing vs. controls. Cells treated with h-miR-146a or h-miR-424 had decreased p-p38 and p-EGFR staining, but these increased over control levels close to the wound edge upon antagomir treatment. In conclusion, several miRNAs with increased expression in human diabetic central corneas were found. Two such miRNAs inhibited cultured corneal epithelial cell wound healing. Dysregulation of miRNA expression in human diabetic cornea may be an important mediator of abnormal wound healing.