N-Cadherin Expression Is Associated with Acquisition of EMT Phenotype and with Enhanced Invasion in Erlotinib-Resistant Lung Cancer Cell Lines

Background

The epidermal growth-factor receptor tyrosine kinase inhibitors have been effective in non-small cell lung cancer patients. However, acquired resistance eventually develops in most patients despite an initial positive response. Emerging evidence suggests that there is a molecular connection between acquired resistance and the epithelial–mesenchymal transition (EMT). N-cadherin is involved in the EMT and in the metastasis of cancer cells. Here, we analyzed N-cadherin expression and function in erlotinib-resistant lung cancer cell lines.

Methods

H1650 cell lines were used to establish the subline resistant to erlotinib(H1650ER). Then, induction of the EMT was analyzed using immunostaining and western blots in H1650ER cells. N-cadherin expression in the resistant cells was examined using FACS and western blot. In addition, an invasion assay was performed to characterize the resistant cells. The effects of N-cadherin on cell proliferation and invasion were analyzed. The association of N-cadherin expression with the EMT phenotype was investigated using immunohistochemical analysis of 13 archived, lung adenocarcinoma tissues, before and after treatment with erlotinib.

Results

In H1650ER cells, N-cadherin expression was upregulated, paralleled by the reduced expression of E-cadherin. The marked histological change and the development of a spindle-like morphology suggest that H1650ER cells underwent an EMT, accompanied by a decrease in E-cadherin and an increase in vimentin. A change in the EMT status between pre-and post-treatment was observed in 11 out of 13 cases (79%). In biopsies of resistant cancers, N-cadherin expression was increased in 10 out of 13 cases. Induction of the EMT was consistent with aggressive characteristics. Inhibition of N-cadherin expression by siRNA was tested to reduce proliferation and invasion of H1650ER cells in vitro.

Conclusions

Our data provide evidence that induction of the EMT contributes to the acquired resistance to EGFR-TKIs in lung cancer. It suggests that N-cadherin is a potential molecular target in the treatment of NSCLC.     

RANKL Promotes Migration and Invasion of Hepatocellular Carcinoma Cells via NF-κB-Mediated Epithelial-Mesenchymal Transition

Background

Metastasis accounts for the most deaths in patients with hepatocellular carcinoma (HCC). Receptor activator of nuclear factor kappa B ligand (RANKL) is associated with cancer metastasis, while its role in HCC remains largely unknown.

Methods

Immunohistochemistry was performed to determine the expression of RANK in HCC tissue (n = 398). Quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot were used to examine the expression of RANK, E-cadherin, N-cadherin, vimentin, Snail, Slug, Twist and MMPs in HCC cells. Wound healing and Transwell assays were used to evaluate cell migration and invasion ability.

Results

We found that expression of RANK, the receptor of RANKL, was significantly higher in HCC tumor tissues than in peritumor liver tissues (p<0.001). Constitutive expression of RANK was detected in HCC cell lines, which can be up-regulated when HCC cells were stimulated with RANKL. Notably, in vitro experiments showed that activation of RANKL-RANK axis significantly promoted migration and invasion ability of HCC cells. In addition, RANKL stimulation increased the expression levels of N-cadherin, Snail, and Twist, while decreased the expression of E-cadherin, with concomitant activation of NF-κB signaling pathway. Moreover, administration of the NF-κB inhibitor attenuated RANKL-induced migration, invasion and epithelial-mesenchymal transition of HCC cells.

Conclusions

RANKL could potentiate migration and invasion ability of RANK-positive HCC cells through NF-κB pathway-mediated epithelial-mesenchymal transition, which means that RANKL-RANK axis could be a potential target for HCC therapy.     

MicroRNA-21 (miR-21) Regulates Cellular Proliferation,Invasion, Migration,and Apoptosis by Targeting PTEN,RECK and Bcl-2 in Lung Squamous Carcinoma,Gejiu City,China

Background

In South China (Gejiu City, Yunnan Province), lung cancer incidence and associated mortality rate is the most prevalent and observed forms of cancer. Lung cancer in this area is called Gejiu squamous cell lung carcinoma (GSQCLC). Research has demonstrated that overexpression of miR-21 occurs in many cancers. However, the unique relationship between miR-21 and its target genes in GSQCLC has never been investigated. The molecular mechanism involved in GSQCLC must be compared to other non-small cell lung cancers in order to establish a relation and identify potential therapeutic targets.

Methodology/Principal Findings

In the current study, we initially found overexpression of miR-21 occurring in non-small cell lung cancer (NSCLC) cell lines when compared to the immortalized lung epithelial cell line BEAS-2B. We also demonstrated that high expression of miR-21 could increase tumor cell proliferation, invasion, viability, and migration in GSQCLC cell line (YTMLC-90) and NSCLC cell line (NCI-H157). Additionally, our results revealed that miR-21 could suppress YTMLC-90 and NCI-H157 cell apoptosis through arresting cell-cycle at G₂/M phase. Furthermore, we demonstrated that PTEN, RECK and Bcl-2 are common target genes of miR-21 in NSCLC. Finally, our studies showed that down-regulation of miR-21 could lead to a significant increase in PTEN and RECK and decrease in Bcl-2 at the mRNA and protein level in YTMLC-90 and NCI-H157 cell lines. However, we have not observed any remarkable difference in the levels of miR-21 and its targets in YTMLC-90 cells when compared with NCI-H157 cells.

Conclusions/Significance

miR-21 simultaneously regulates multiple programs that enhance cell proliferation, apoptosis and tumor invasiveness by targeting PTEN, RECK and Bcl-2 in GSQCLC. Our results demonstrated that miR-21 may play a vital role in tumorigenesis and progression of lung squamous cell carcinoma and suppression of miR-21 may be a novel approach for the treatment of lung squamous cell carcinoma.     

Inhibition of mTORC1 induces loss of E-cadherin through AKT/GSK-3β signaling-mediated upregulation of E-cadherin repressor complexes in non-small cell lung cancer cells

Background

mTOR, which can form mTOR Complex 1 (mTORC1) or mTOR Complex 2 (mTORC2) depending on its binding partners, is frequently deregulated in the pulmonary neoplastic conditions and interstitial lung diseases of the patients treated with rapalogs. In this study, we investigated the relationship between mTOR signaling and epithelial mesenchymal transition (EMT) by dissecting mTOR pathways.

Methods

Components of mTOR signaling pathway were silenced by shRNA in a panel of non-small cell lung cancer cell lines and protein expression of epithelial and mesenchymal markers were evaluated by immunoblotting and immunocytochemistry. mRNA level of the E-cadherin repressor complexes were evaluated by qRT-PCR.

Results

IGF-1 treatment decreased expression of the E-cadherin and rapamycin increased its expression, suggesting hyperactivation of mTOR signaling relates to the loss of E-cadherin. Genetic ablation of rapamycin-insensitive companion of mTOR (Rictor), a component of mTORC2, did not influence E-cadherin expression, whereas genetic ablation of regulatory-associated protein of mTOR (Raptor), a component of mTORC1, led to a decrease in E-cadherin expression at the mRNA level. Increased phosphorylation of AKT at Ser473 and GSK-3β at Ser9 were observed in the Raptor-silenced NSCLC cells. Of the E-cadherin repressor complexes tested, Snail, Zeb2, and Twist1 mRNAs were elevated in raptor-silenced A549 cells, and Zeb2 and Twist1 mRNAs were elevated in Raptor-silenced H2009 cells. These findings were recapitulated by treatment with the GSK-3β inhibitor, LiCl. Raptor knockdown A549 cells showed increased expression of N-cadherin and vimentin with mesenchymal phenotypic changes.

Conclusions

In conclusion, selective inhibition of mTORC1 leads to hyperactivation of the AKT/GSK-3β pathway, inducing E-cadherin repressor complexes and EMT. These findings imply the existence of a feedback inhibition loop of mTORC1 onto mTORC2 that plays a role in the homeostasis of E-cadherin expression and EMT, requiring caution in the clinical use of rapalog and selective mTORC1 inhibitors.     

Forkhead Box L1 Is Frequently Downregulated in Gallbladder Cancer and Inhibits Cell Growth through Apoptosis Induction by Mitochondrial Dysfunction

Background

Forkhead box L1 (FOXL1), considered as a novel candidate tumor suppressor, suppresses proliferation and invasion in certain cancers. However, the regulation and function of FOXL1 in gallbladder cancer (GBC) remains unclear.

Methods

FOXL1 expression at mRNA and protein levels in GBC tissues and cell lines were examined by RT-PCR, immunohistochemistry and western blot assay. FOXL1 expression in GBC cell lines was up-regulated by transfection with pcDNA-FOXL1. The effects of FOXL1 overexpression on cell proliferation, apoptosis, migration and invasion were evaluated in vitro or in vivo. In addition, the status of mediators involved in migration, invasion and apoptosis was examined using western blot after transfection with pcDNA-FOXL1.

Results

FOXL1 was frequently downregulated in GBC tissues and cell lines. Its higher expression is associated with better prognosis, while its lower expression is correlated with advanced TNM stage and poor differentiation. FOXL1 overexpression in NOZ cells significantly suppresses cell proliferation, migration and invasion in vitro and tumorigenicity in nude mice. FOXL1 overexpression disrupted mitochondrial transmembrane potential and triggered mitochondria-mediated apoptosis in NOZ cells. In addition, FOXL1 overexpression suppressed ZEB1 expression and induced E-cadherin expression in NOZ cells.

Conclusion

Our findings suggested that dysregulated FOXL1 is involved in tumorigenesis and progression of GBC and may serve as a predictor of clinical outcome or even a therapeutic target for patients with GBC.     

Over-expression of LSD1 promotes proliferation, migration and invasion in non-small cell lung cancer

Background

Lysine specific demethylase 1 (LSD1) has been identified and biochemically characterized in epigenetics, but the pathological roles of its dysfunction in lung cancer remain to be elucidated. The aim of this study was to evaluate the prognostic significance of LSD1 expression in patients with non-small cell lung cancer (NSCLC) and to define its exact role in lung cancer proliferation, migration and invasion.

Methods

The protein levels of LSD1 in surgically resected samples from NSCLC patients were detected by immunohistochemistry or Western blotting. The mRNA levels of LSD1 were detected by qRT-PCR. The correlation of LSD1 expression with clinical characteristics and prognosis was determined by statistical analysis. Cell proliferation rate was assessed by MTS assay and immunofluorescence. Cell migration and invasion were detected by scratch test, matrigel assay and transwell invasion assay.

Results

LSD1 expression was higher in lung cancer tissue more than in normal lung tissue. Our results showed that over-expression of LSD1 protein were associated with shorter overall survival of NSCLC patients. LSD1 was localized mainly to the cancer cell nucleus. Interruption of LSD1 using siRNA or a chemical inhibitor, pargyline, suppressed proliferation, migration and invasion of A549, H460 and 293T cells. Meanwhile, over-expression of LSD1 enhanced cell growth. Finally, LSD1 was shown to regulate epithelial-to-mesenchymal transition in lung cancer cells.

Conclusions

Over-expression of LSD1 was associated with poor prognosis in NSCLC, and promoted tumor cell proliferation, migration and invasion. These results suggest that LSD1 is a tumor-promoting factor with promising therapeutic potential for NSCLC.     

RNPC1 inhibits non-small cell lung cancer progression via regulating miR-181a/CASC2 axis

Objectives

To study the roles and mechanisms of RNA binding protein RNPC1 in non-small cell lung cancer progression.

Results

RNPC1 and long non-coding RNA CASC2 expression levels were significantly downregulated in lung cancer tissues compared with normal adjacent tissues, and their expression levels were positively correlated. Functionally, overexpression of RNPC1 or CASC2 inhibited non-small cell lung cancer cells proliferation, migration and invasion, and promoted cells apoptosis. Mechanistically, RNPC1 was found to harbor binding sites on CASC2 and directly bound to CASC2, and increased CASC2 mRNA stability and expression. Notably, the promotive effects of RNPC1 on CASC2 expression were attenuated by miR-181a overexpression. Moreover, CASC2 3′UTR with mutated miR-181a binding sites did not respond to RNPC1 alteration. Finally, the inhibitory effects of RNPC1 overexpression were attenuated or even reversed by CASC2 knockdown or miR-181a overexpression.

Conclusions

RNA bind protein RNPC1 could inhibit non-small cell lung cancer progression by competitively binding to CASC2 with miR-181a.

     

Effects of MICA Expression on the Prognosis of Advanced Non-Small Cell Lung Cancer and the Efficacy of CIK Therapy

Objective

To investigate the clinical significance of the expression of MHC class I chain-related gene A (MICA) in patients with advanced non-small cell lung cancer and explore the relationship between MICA expression and the efficacy of cytokine-induced killer cell (CIK) therapy for treating advanced non-small cell lung cancer.

Methods

We obtained data on 222 patients with advanced non-small cell lung cancer, including data on MICA expression, age, gender, ECOG score, pathological type, stage, treatment history (including 38 patients who were given autologous CIK cell infusion), and overall survival (OS). MICA expression in lung cancer tissue was evaluated by immunohistochemical staining. Analyses of MICA expression, and CIK therapy association with survival outcomes were performed using Cox proportional models, Kaplan-Meier methods, and the log-rank test.

Result

s MICA was expressed in both membrane and cytoplasm. MICA expression correlated with the stage of lung cancer, ECOG score, gender and age. Multivariate COX regression analysis showed that the expression of MICA was an independent prognostic factor of advanced non-small cell lung cancer (p = 0.002). In subgroup analysis, we divided the 222 patients into CIK and control groups. In the CIK group, the medium OS (mOS) of patients with a high expression of MICA was longer than in those with low expression of MICA (27 months vs. 13 months). In the control group, the mOS in patients with a high expression of MICA was shorter than in patients with low MICA expression (9 months vs. 18 months). COX regression analysis showed that the MICA expression affects the effect of CIK therapy (p<0.0001).

Conclusion

1) The high expression of MICA is one of the indicators of a poor prognosis for advanced non-small cell lung cancer patients. 2) The high expression of MICA might be one of the predictive factors for successful CIK therapy.     

Suppression of Lung Tumorigenesis by Leucine Zipper/EF Hand–Containing Transmembrane-1

Background

Leucine zipper/EF hand-containing transmembrane-1 (LETM1) encodes for the human homologue of yeast Mdm38p, which is a mitochondria-shaping protein of unclear function. However, a previous study demonstrated that LETM1 served as an anchor protein for complex formation between mitochondria and ribosome, and regulated mitochondrial biogenesis.

Methodology/Principal Findings

Therefore, we examine the possibility that LETM1 may function to regulate mitochondria and lung tumor growth. In this study, we addressed this question by studying in the effect of adenovirus-mediated LETM1 in the lung cancer cell and lung cancer model mice. To investigate the effects of adenovirus-LETM1 in vitro, we infected with adenovirus-LETM1 in A549 cells. Additionally, in vivo effects of LETM1 were evaluated on K-ras ^LA1 mice, human non-small cell lung cancer model mice, by delivering the LETM1 via aerosol through nose-only inhalation system. The effects of LETM1 on lung cancer growth and AMPK related signals were evaluated. Adenovirus-mediated overexpression of LETM1 could induce destruction of mitochondria of lung cancer cells through depleting ATP and AMPK activation. Furthermore, adenoviral-LETM1 also altered Akt signaling and inhibited the cell cycle while facilitating apoptosis. Theses results demonstrated that adenovirus-LETM1 suppressed lung cancer cell growth in vitro and in vivo.

Conclusions/Significance

Adenovirus-mediated LETM1 may provide a useful target for designing lung tumor prevention and treatment.     

Genes suppressed by DNA methylation in non-small cell lung cancer reveal the epigenetics of epithelial–mesenchymal transition

Background

DNA methylation is associated with aberrant gene expression in cancer, and has been shown to correlate with therapeutic response and disease prognosis in some types of cancer. We sought to investigate the biological significance of DNA methylation in lung cancer.

Results

We integrated the gene expression profiles and data of gene promoter methylation for a large panel of non-small cell lung cancer cell lines, and identified 578 candidate genes with expression levels that were inversely correlated to the degree of DNA methylation. We found these candidate genes to be differentially methylated in normal lung tissue versus non-small cell lung cancer tumors, and segregated by histologic and tumor subtypes. We used gene set enrichment analysis of the genes ranked by the degree of correlation between gene expression and DNA methylation to identify gene sets involved in cellular migration and metastasis. Our unsupervised hierarchical clustering of the candidate genes segregated cell lines according to the epithelial-to-mesenchymal transition phenotype. Genes related to the epithelial-to-mesenchymal transition, such as AXL, ESRP1, HoxB4, and SPINT1/2, were among the nearly 20% of the candidate genes that were differentially methylated between epithelial and mesenchymal cells. Greater numbers of genes were methylated in the mesenchymal cells and their expressions were upregulated by 5-azacytidine treatment. Methylation of the candidate genes was associated with erlotinib resistance in wild-type EGFR cell lines. The expression profiles of the candidate genes were associated with 8-week disease control in patients with wild-type EGFR who had unresectable non-small cell lung cancer treated with erlotinib, but not in patients treated with sorafenib.

Conclusions

Our results demonstrate that the underlying biology of genes regulated by DNA methylation may have predictive value in lung cancer that can be exploited therapeutically.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2164-15-1079) contains supplementary material, which is available to authorized users.     

N-Cadherin Negatively Regulates Osteoblast Proliferation and Survival by Antagonizing Wnt,ERK and PI3K/Akt Signalling

Background

Osteoblasts are bone forming cells that play an essential role in osteogenesis. The elucidation of the mechanisms that control osteoblast number is of major interest for the treatment of skeletal disorders characterized by abnormal bone formation. Canonical Wnt signalling plays an important role in the control of osteoblast proliferation, differentiation and survival. Recent studies indicate that the cell-cell adhesion molecule N-cadherin interacts with the Wnt co-receptors LRP5/6 to regulate osteoblast differentiation and bone accrual. The role of N-cadherin in the control of osteoblast proliferation and survival remains unknown.

Methods and Principal Findings

Using murine MC3T3-E1 osteoblastic cells and N-cadherin transgenic mice, we demonstrate that N-cadherin overexpression inhibits cell proliferation in vitro and in vivo. The negative effect of N-cadherin on cell proliferation results from decreased Wnt, ERK and PI3K/Akt signalling and is restored by N-cadherin neutralizing antibody that antagonizes N-cadherin-LRP5 interaction. Inhibition of Wnt signalling using DKK1 or Sfrp1 abolishes the ability of N-cadherin blockade to restore ERK and PI3K signalling and cell proliferation, indicating that the altered cell growth in N-cadherin overexpressing cells is in part secondary to alterations in Wnt signalling. Consistently, we found that N-cadherin overexpression inhibits the expression of Wnt3a ligand and its downstream targets c-myc and cyclin D1, an effect that is partially reversed by N-cadherin blockade. We also show that N-cadherin overexpression decreases osteoblast survival in vitro and in vivo. This negative effect on cell survival results from inhibition of PI3K/Akt signalling and increased Bax/Bcl-2, a mechanism that is rescued by Wnt3a.

Conclusion

The data show that N-cadherin negatively controls osteoblast proliferation and survival via inhibition of autocrine/paracrine Wnt3a ligand expression and attenuation of Wnt, ERK and PI3K/Akt signalling, which provides novel mechanisms by which N-cadherin regulates osteoblast number.     

Antihelminthic benzimidazoles potentiate navitoclax (ABT-263) activity by inducing Noxa-dependent apoptosis in non-small cell lung cancer (NSCLC) cell lines

Background

Evasion of apoptosis is a hallmark of cancer cells. One mechanism to deregulate the apoptotic pathway is by upregulation of the anti-apoptotic Bcl-2 family members. Navitoclax (ABT-263) is a Bcl-2/Bcl-x_L inhibitor that restores the ability of cancer cells to undergo apoptosis.

Methods

In this study we performed a high-throughput screen with 640 FDA-approved drugs to identify potential therapeutic combinations with navitoclax in a non-small cell lung cancer (NSCLC) cell line.

Results

Other than a panel of cancer compounds such as doxorubicin, camptothecin, and docetaxel, four antihelminthic compounds (benzimidazoles) potentiated navitoclax activity. Treatment with benzimidazoles led to induction of the pro-apoptotic protein Noxa at the mRNA and protein level. Noxa binds and antagonizes antiapoptotic protein Mcl-1. siRNA-mediated knock-down of Noxa completely rescued benzimidazole-potentiated navitoclax activity. In addition, inhibiting caspase 3 and 9 partially rescued benzimidazole-potentiated navitoclax activity.

Conclusions

We have identified compounds and mechanisms which potentiate navitoclax activity in lung cancer cell lines. Further validation of the benzimidazole-potentiated navitoclax effect in vivo is required to evaluate the potential for translating this observation into clinical benefit.

Electronic supplementary material

The online version of this article (doi:10.1186/s12935-014-0151-3) contains supplementary material, which is available to authorized users.     

FoxM1 Is Associated with Poor Prognosis of Non-Small Cell Lung Cancer Patients through Promoting Tumor Metastasis

Background

FoxM1 has been reported to be important in initiation and progression of various tumors. However, whether FoxM1 has any indication for prognosis in non-small cell lung cancer patients remains unclear.

Methodology/Principal Findings

In this study, FoxM1 expression in tumor cells was examined first by immunohistochemistry in 175 NSCLC specimens, the result of which showed that FoxM1 overexpression was significantly associated with positive smoking status (P = 0.001), poorer tissue differentiation (P = 0.0052), higher TNM stage (P<0.0001), lymph node metastasis (P<0.0001), advanced tumor stage (P<0.0001), and poorer prognosis (P<0.0001). Multivariable analysis showed that FoxM1 expression increased the hazard of death (hazard ratio, 1.899; 95% CI, 1.016–3.551). Furthermore, by various in vitro and in vivo experiments, we showed that targeted knockdown of FoxM1 expression could inhibit the migratory and invasive abilities of NSCLC cells, whereas enforced expression of FoxM1 could increased the invasion and migration of NSCLC cells. Finally, we found that one of the cellular mechanisms by which FoxM1 promotes tumor metastasis is through inducing epithelial-mesenchymal transition (EMT) program.

Conclusions

These results suggested that FoxM1 overexpression in tumor tissues is significantly associated with the poor prognosis of NSCLC patients through promoting tumor metastasis.     

Gremlin is Overexpressed in Lung Adenocarcinoma and Increases Cell Growth and Proliferation in Normal Lung Cells

Background

Gremlin, a member of the Dan family of BMP antagonists, is a glycosylated extracellular protein. Previously Gremlin has been shown to play a role in dorsal-ventral patterning, in tissue remodeling, and recently in angiogenesis. Evidence has previously been presented showing both over- and under-expression of Gremlin in different tumor tissues. Here, we sought to quantify expression of Gremlin in cancers of the lung and performed in vitro experiments to check whether Gremlin promotes cell growth and proliferation.

Methodology/Principal Findings

Expression of Gremlin in 161 matched tumor and normal lung cancer specimens is quantified by quantitative real-time PCR and protein level is measured by immunohistochemistry. GREM1 was transfected into lung fibroblast and epithelial cell lines to assess the impact of overexpression of Gremlin in vitro.

Results

Lung adenocarcinoma but not squamous cell carcinoma shows a significant increase in Gremlin expression by mRNA and protein level. Lung fibroblast and epithelial cell lines transfected with GREM1 show significantly increased cell proliferation.

Conclusions/Significance

Our data suggest that Gremlin acts in an oncogenic manner in lung adenocarcinoma and could hold promise as a new diagnostic marker or potential therapeutic target in lung AD or general thoracic malignancies.     

SPARC Is a Key Regulator of Proliferation, Apoptosis and Invasion in Human Ovarian Cancer

Background

Secreted protein acidic and rich in cysteine (SPARC), a calcium-binding matricellular glycoprotein, is implicated in the progression of many cancers. In this study, we investigated the expression and function of SPARC in ovarian cancer.

Methods

cDNA microarray analysis was performed to compare gene expression profiles of the highly invasive and the low invasive subclones derived from the SKOV3 human ovarian cancer cell line. Immunohistochemistry (IHC) staining was performed to investigate SPARC expression in a total of 140 ovarian tissue specimens. In functional assays, effects of SPARC knockdown on the biological behavior of ovarian cancer cells were investigated. The mechanisms of SPARC in ovarian cancer proliferation, apoptosis and invasion were also researched.

Results

SPARC was overexpressed in the highly invasive subclone compared with the low invasive subclone. High SPARC expression was associated with high stage, low differentiation, lymph node metastasis and poor prognosis of ovarian cancer. Knockdown of SPARC expression significantly suppressed ovarian cancer cell proliferation, induced cell apoptosis and inhibited cell invasion and metastasis.

Conclusion

SPARC is overexpressed in highly invasive subclone and ovarian cancer tissues and plays an important role in ovarian cancer growth, apoptosis and metastasis.     

MiRNA-145 suppresses lung adenocarcinoma cell invasion and migration by targeting N-cadherin

Objective

To investigate the roles of miR-145 in lung adenocarcinoma (LAC) and to clarify the regulation of N-cadherin by miR-145.

Results

In 57 paired clinical LAC tissues, diminished miR-145 was significantly correlated with the lymph node metastasis and was negatively correlated with N-cadherin mRNA level expression. Wound healing and transwell assays revealed a reduced capability of tumor metastasis induced by miR-145 in LAC. miR-145 negatively regulated the invasion of cell lines through targeting N-cadherin by directly binding to its 3′-untranslated region. Silencing of N-cadherin inhibited invasion and migration of LAC cell lines similar to miR-145 overexpression.

Conclusions

MiR-145 could inhibit invasion and migration of lung adenocarcinoma cell lines by directly targeting N-cadherin.

     

miR-30b,Down-Regulated in Gastric Cancer,Promotes Apoptosis and Suppresses Tumor Growth by Targeting Plasminogen Activator Inhibitor-1

Background

Gastric cancer is one of the most common malignant diseases worldwide. Emerging evidence has shown that microRNAs (miRNAs) are associated with tumor development and progression. Our previous studies have revealed that H. pylori infection was able to induce the altered expression of miR-30b in gastric epithelial cells. However, little is known about the potential role of miR-30b in gastric cancer.

Methods

We analyzed the expression of miR-30b in gastric cancer cell lines and human gastric cancer tissues. We examined the effect of miR-30b mimics on the apoptosis of gastric cancer cells in vitro by flow cytometry (FCM) and caspase-3/7 activity assays. Nude mouse xenograft model was used to determine whether miR-30b is involved in tumorigenesis of gastric cancer. The target of miR-30b was identified by bioinformatics analysis, luciferase assay and Western blot. Finally, we performed the correlation analysis between miR-30b and its target expression in gastric cancer.

Results

miR-30b was significantly down-regulated in gastric cancer cells and human gastric cancer tissues. Enforced expression of miR-30b promoted the apoptosis of gastric cancer cells in vitro, and miR-30b could significantly inhibit tumorigenicity of gastric cancer by increasing the apoptosis proportion of cancer cells in vivo. Moreover, plasminogen activator inhibitor-1 (PAI-1) was identified as the potential target of miR-30b, and miR-30b level was inversely correlated with PAI-1 expression in gastric cancer. In addition, silencing of PAI-1 was able to phenocopy the effect of miR-30b overexpression on apoptosis regulation of cancer cells, and overexpression of PAI-1 could suppressed the effect of promoting cell apoptosis by miR-30b, indicating PAI-1 is potentially involved in miR-30b-induced apoptosis on cancer cells.

Conclusion

miR-30b may function as a novel tumor suppressor gene in gastric cancer by targeting PAI-1 and regulating the apoptosis of cancer cells. miR-30b could serve as a potential biomarker and therapeutic target against gastric cancer.