ADAM9 up-regulates N-cadherin via miR-218 suppression in lung adenocarcinoma cells

MiR-22-3p suppresses NSCLC cell migration and EMT via targeting RAC1 expression

Previous studies have demonstrated the tumor-suppressive function of microRNA-22-3p (miR-22-3p) in several cancers, whereas the significance of miR-22-3p in non-small cell lung cancer (NSCLC) remains unclear. In this study, we explored the biological function and molecular mechanism of miR-22-3p in NSCLC cells. First, we assessed the expression of miR-22-3p in NSCLC tissues and cells based on RT-qPCR and TCGA database. Compared with normal lung tissues and cells, miR-22-3p expression was dramatically decreased in lung cancer tissues and cells. miR-22-3p expression was also correlated with lymph node metastasis and tumor size, but not TNM stages. We further explored the in vitro function of miR-22-3p on the migration and epithelial-mesenchymal transition (EMT) of NSCLC cells. The results showed that overexpression of miR-22-3p suppressed the migration and EMT of NSCLC cells, whereas silencing miR-22-3p showed the opposite effect. Luciferase assay demonstrated that RAS-related C3 botulinum toxin substrate 1 (RAC1) was the target gene for miR-22-3p. Mechanistically, we demonstrated that miR-22-3p suppressed the cell migration and EMT via downregulation of RAC1 because the inhibitory effect of miR-22-3p on cell migration and EMT of NSCLC cells was reversed by RAC1 overexpression. Based on these novel data, the miR-22-3p/RAC1 axis may be an alternative target in the therapeutic intervention of NSCLC.

Relevance of A Disintegrin and Metalloproteinase Domain-Containing (ADAM)9 Protein Expression to Bladder Cancer Malignancy

We evaluated the effect of A Disintegrin and Metalloproteinase Domain-Containing (ADAM)9 protein on exacerbation in bladder cancer KK47 and T24. First, we knocked down ADAM9 and investigated cell proliferation, migration, cell cycle, and the epithelial-mesenchymal transition (EMT)-related proteins expression in vitro. We then investigated the expression level of ADAM9 in clinical urine cytology samples and the Cancer Genome Atlas (TCGA) data. Cell proliferation was significantly reduced in both cell lines after ADAM9 knockdown. In the cell-cycle assay, the percentage of G0/G1 cells was significantly increased in ADAM9 knockdown T24. Migration of T24 was more strongly suppressed than KK47. The expression level of EMT-related proteins suggested that EMT was suppressed in ADAM9 knockdown T24. TCGA analysis revealed that ADAM9 mRNA expression was significantly higher in stage IV and high-grade cancer than in other stages and low-grade cancer. Moreover, in the gene expression omnibus (GEO) study, bladder cancer with surrounding carcinoma and invasive carcinoma showed significantly high ADAM9 mRNA expression. We found that ADAM9 knockdown suppressed cell proliferation and migration in bladder cancer and that high-grade bladder cancer is correlated with higher expression of ADAM9.

The Profile of MicroRNA Expression and Potential Role in the Regulation of Drug-Resistant Genes in Doxorubicin and Topotecan Resistant Ovarian Cancer Cell Lines

Epithelial ovarian cancer has the highest mortality among all gynecological malignancies. The main reasons for high mortality are late diagnosis and development of resistance to chemotherapy. Resistance to chemotherapeutic drugs can result from altered expression of drug-resistance genes regulated by miRNA. The main goal of our study was to detect differences in miRNA expression levels in two doxorubicin (DOX)- and two topotecan (TOP)-resistant variants of the A2780 drug-sensitive ovarian cancer cell line by miRNA microarray. The next aim was to recognize miRNAs as factors responsible for the regulation of drug-resistance genes. We observed altered expression of 28 miRNA that may be related to drug resistance. The upregulation of miR-125b-5p and miR-935 and downregulation of miR-218-5p was observed in both DOX-resistant cell lines. In both TOP-resistant cell lines, we noted the overexpression of miR-99a-5p, miR-100-5p, miR-125b-5p, and miR-125b-2-3p and decreased expression of miR-551b-3p, miR-551b-5p, and miR-383-5p. Analysis of the targets suggested that expression of important drug-resistant genes such as the collagen type I alpha 2 chain (COL1A2), protein Tyrosine Phosphatase Receptor Type K (PTPRK), receptor tyrosine kinase—EPHA7, Roundabout Guidance Receptor 2 (ROBO2), myristoylated alanine-rich C-kinase substrate (MARCK), and the ATP-binding cassette subfamily G member 2 (ABCG2) can be regulated by miRNA.

Identification of theranostic factors for patients developing metastasis after surgery for early-stage lung adenocarcinoma

Rationale: Lung adenocarcinoma (LUAD) is an aggressive disease with high propensity of metastasis. Among patients with early-stage disease, more than 30% of them may relapse or develop metastasis. There is an unmet medical need to stratify patients with early-stage LUAD according to their risk of relapse/metastasis to guide preventive or therapeutic approaches. In this study, we identified 4 genes that can serve both therapeutic and diagnostic (theranostic) purposes.

Methods: Three independent datasets (GEO, TCGA, and KMPlotter) were used to evaluate gene expression profile of patients with LUAD by unbiased screening approach. Upon significant genes uncovered, functional enrichment analysis was carried out. The predictive power of their expression on patient prognosis were evaluated. Once confirmed their theranostic roles by integrated bioinformatics, we further conducted in vitro and in vivo validation.

Results: We found that four genes (ADAM9, MTHFD2, RRM2, and SLC2A1) were associated with poor patient outcomes with an increased hazard ratio in LUAD. Knockdown of them, both separately and simultaneously, suppressed lung cancer cell proliferation and migration ability in vitro and prolonged survival time in metastatic tumor mouse models. Moreover, these four biomarkers were found to be overexpressed in tumor tissues from LUAD patients, and the total immunohistochemical staining scores correlated with poor prognosis.

Conclusions: These results suggest that these four identified genes could be theranostic biomarkers for stratifying high-risk patients who develop relapse/metastasis in early-stage LUAD. Developing therapeutic approaches for the four biomarkers may benefit early-stage LUAD patients after surgery.

The emerging role of the MiR-1272-ADAM9-CDCP1 signaling pathway in the progression of glioma

Glioma is a primary, malignant, and aggressive brain tumor in adults. To develop new therapeutic strategies for glioma, we must determine its underlying mechanisms. In the present study, we aimed to investigate the potential role of miR-1272-ADAM9-CDCP1 signaling in the progression of glioma. We found that ectopic expression of miR-1272 produced significant inhibitory effects on cell proliferation and migration and was associated with cell cycle G0/G1 arrest in A172 and SHG44 glioma cells. Using the luciferase reporter assay, we identified ADAM9 as a target of miR-1272. The expression of ADAM9 was markedly decreased or increased after overexpression or inhibition, respectively, of miR-1272 in glioma cells. Moreover, overexpression of ADAM9 reversed the inhibitory effects of miR-1272 on glioma cell progression. Furthermore, CDCP1 served as a potential downstream molecule of miR-1272/ADAM9 signaling in glioma and promoted the proliferation and migration of glioma. Results derived from clinical samples and online databases confirmed correlations between the expression of ADAM9 and CDCP1 and both the severity and prognosis of glioma. In conclusion, these results suggest that miR-1272 and CDCP1 may act as novel regulators in glioma. The miR-1272/ADAM9/CDCP1 pathway may serve as a potential candidate pathway for the prevention of glioma.

Resveratrol-mediated ADAM9 degradation decreases cancer progression and provides synergistic effects in combination with chemotherapy

Metastasis is a crucial hallmark of cancer progression and remains the primary cause of patient deaths. Metastasis-associated proteases contribute to cancer progression by disrupting the extracellular matrix interaction to facilitate the spreading of cancer cells to other organs. ADAM9, a type of metalloprotease, has been reported to promote tumor biology and is associated with clinicopathological features such as poor outcome, therapy resistance, and metastasis formation. Targeting ADAM9 might serve as a putative therapeutic application; however, this option is currently unavailable. Resveratrol, a polyphenol from plants, has been shown to be promising for cancer treatment due to its wide variety of biological effects with few side effects. In this study, we demonstrated that resveratrol inhibits cancer cell migration and viability in lung and esophageal cancer cells through the regulation of ADAM9. Mechanistically, resveratrol inhibits ADAM9 protein expression in cancer cells through the ubiquitin-proteasome pathway. Moreover, resveratrol provides synergistic anticancer effects when combined with clinical chemotherapeutics. Our data suggests that resveratrol may inhibit human lung cancer and ESCC progression by inhibiting ADAM9 expression, thus providing a potential mechanism for the anticancer action of resveratrol.

Primary tumor and metastasis-sectioning the different steps of the metastatic cascade

Patients with lung cancer in the majority die of metastases. Treatment options include surgery, chemo- and radiotherapy, targeted therapy by tyrosine kinase inhibitors (TKIs), and immuno-oncologic treatment. Despite the success with these treatment options, cure of lung cancer is achieved in only a very small proportion of patients. In most patients’ recurrence and metastasis will occur, and finally kill the patient. Metastasis is a multistep procedure. It requires a change in adhesion of tumor cells for detachment from their neighboring cells. The next step is migration either as single cells [epithelial-mesenchymal transition (EMT)], or as cell clusters (hybrid-EMT or bulk migration). A combination of genetic changes is required to facilitate migration. Then tumor cells have to orient themselves along matrix proteins, detect oxygen concentrations, prevent attacks by immune cells, and induce a tumor-friendly switch of stroma cells (macrophages, myofibroblasts, etc.). Having entered the blood stream tumor cells need to adapt to shear stress, avoid being trapped by coagulation, but also use coagulation in small veins for adherence to endothelia, and express homing molecules for extravasation. Within a metastatic site, tumor cells need a well-prepared niche to establish a metastatic focus. Tumor cells again have to establish a vascular net for maintaining nutrition and oxygen supply, communicate with stroma cells, grow out and set further metastases. In this review the different steps will be discussed with a focus on pulmonary carcinomas. The vast amount of research manuscripts published so far are not easy to analyze: in most reports’ single steps of the metastatic cascade are interpreted as evidence for the whole process; for example, migration is interpreted as evidence for metastasis. In lung cancer most often latency periods are shorter, in between 1–5 years. In other cases, despite widespread migration occurs, tumor cells die within the circulation and do not reach a metastatic site. Therefore, migration is a requisite, but does not necessarily predict metastasis. The intention of this review is to point to these different aspects and hopefully provoke research directed into a more functional analysis of the metastatic process.

miR-218 Inhibits Mitochondrial Clearance by Targeting PRKN E3 Ubiquitin Ligase

The selective elimination of dysfunctional mitochondria through mitophagy is crucial for preserving mitochondrial quality and cellular homeostasis. The most described mitophagy pathway is regulated by a positive ubiquitylation feedback loop in which the PINK1 (PTEN induced kinase 1) kinase phosphorylates both ubiquitin and the E3 ubiquitin ligase PRKN (Parkin RBR E3 ubiquitin ligase), also known as PARKIN. This event recruits PRKN to the mitochondria, thus amplifying ubiquitylation signal. Here we report that miR-218 targets PRKN and negatively regulates PINK1/PRKN-mediated mitophagy. Overexpression of miR-218 reduces PRKN mRNA levels, thus also reducing protein content and deregulating the E3 ubiquitin ligase action. In fact, following miR-218 overexpression, mitochondria result less ubiquitylated and the autophagy machinery fails to proceed with correct mitochondrial clearance. Since mitophagy defects are associated with various human diseases, these results qualify miR-218 as a promising therapeutic target for human diseases.

Therapeutic effects of statins against lung adenocarcinoma via p53 mutant-mediated apoptosis

The p53 gene is an important tumour suppressor gene. Mutant p53 genes account for about half of all lung cancer cases. There is increasing evidence for the anti-tumour effects of statins via inhibition of the mevalonate pathway. We retrospectively investigated the correlation between statin use and lung cancer prognosis using the Taiwanese National Health Insurance Research Database, mainly focusing on early-stage lung cancer. This study reports the protective effects of statin use in early-stage lung cancer patients regardless of chemotherapy. Statin treatments reduced the 5-year mortality (odds ratio, 0.43; P < 0.001) in this population-based study. Significantly higher levels of cellular apoptosis, inhibited cell growth, and regulated lipid raft content were observed in mutant p53 lung cancer cells treated with simvastatin. Further, simvastatin increased the caspase-dependent apoptotic pathway, promotes mutant p53 protein degradation, and decreased motile activity in lung cancer cells with p53 missense mutations. These data suggest that statin use in selected lung cancer patients may have clinical benefits.

MicroRNA-425 promotes the development of lung adenocarcinoma via targeting A disintegrin and metalloproteinases 9 (ADAM9)

PURPOSE

We aimed to investigate the roles of microRNA-425 (miR-425) in lung adenocarcinoma, as well as its possible regulatory mechanism.

MATERIALS AND METHODS

The miR-425 expression in lung adenocarcinoma tissues and cells was determined. The regulatory relationship between miR-425 and IL-6/STAT3 signaling was investigated. In addition, miR-425 was downexpressed in H1299 cells, and its effects on cell proliferation and apoptosis were determined. Furthermore, the target relationship between miR-425 and A disintegrin and metalloproteinases 9 (ADAM9) in lung adenocarcinoma cells was explored.

RESULTS

The miR-425 was significantly downregulated in lung adenocarcinoma tissues and cells and was markedly inhibited by IL-6/STAT3 signaling. In addition, miR-425 expression was successfully overexpressed by transfection with pre-miR-425. Overexpression of miR-425 decreased the proliferation and colony formation of H1299 cells and promoted cell apoptosis markedly. Moreover, ADAM9 was revealed as a target of miR-425, and ADAM9 expression was negatively regulated by miR-425.

CONCLUSION

Our findings indicate that downregulation of miR-425 caused by IL-6/STAT3 signaling leads to loss of ADAM9 targeting, results in enhanced ADAM9 expression, and contributes to the development of lung adenocarcinoma. Thus, increasing miR-425 may be a promising therapeutic strategy for this disease.

ADAM9 enhances CDCP1 by inhibiting miR-1 through EGFR signaling activation in lung cancer metastasis

MicroRNAs (miRNAs), which are endogenous short noncoding RNAs, can regulate genes involved in important biological and pathological functions. Therefore, dysregulation of miRNAs plays a critical role in cancer progression. However, whether the aberrant expression of miRNAs is regulated by oncogenes remains unclear. We previously demonstrated that a disintegrin and metalloprotease domain 9 (ADAM9) promotes lung metastasis by enhancing the expression of a pro-migratory protein, CUB domain containing protein 1 (CDCP1). In this study, we found that this process occurred via miR-1 down-regulation. miR-1 expression was down-regulated in lung tumors, but increased in ADAM9-knockdown lung cancer cells, and was negatively correlated with CDCP1 expression as well as the migration ability of lung cancer cells. Luciferase-based reporter assays showed that miR-1 directly bound to the 3′-untranslated region of CDCP1 and inhibited its translation. Treatment with a miR-1 inhibitor restored CDCP1 protein levels and enhanced tumor cell mobility. Overexpression of miR-1 decreased tumor metastases and increased the survival rate in mice. ADAM9 knockdown reduced EGFR signaling and increased miR-1 expression. These results revealed that ADAM9 down-regulates miR-1 via activating EGFR signaling pathways, which in turn enhances CDCP1 expression to promote lung cancer progression.

MiR-448 promotes glycolytic metabolism of gastric cancer by downregulating KDM2B

MicroRNAs are critical in various human cancers, including gastric cancer (GC). However, the mechanism underlying the GC development remains elusive. In this study, we demonstrate that miR-448 is increased in GC samples and cell lines. Overexpression of miR-448 facilitated the proliferation of GC cells by stimulating glycolysis. Mechanistically, we identified KDM2B, a reader for methylated CpGs, as the target of miR-448 that represses glycolysis and promotes oxidative phosphorylation. Overexpression of miR-448 reduced both the mRNA and protein levels of KDM2B, whereas KDM2B re-expression abrogated the miR-448-mediated glycolytic activities. Furthermore, we discovered Myc as a key target of KDM2B that controls metabolic switch in GC. Importantly, a cohort of 81 GC tissues revealed that miR-448 level closely associated with a battery of glycolytic genes, in which KDM2B showed the strongest anti-correlation coefficient. In addition, enhanced miR-448 level was significantly associated with poor clinical outcomes of GC patients. Hence, we identified a previously unappreciated mechanism by which miR-448 orchestrate epigenetic, transcriptional and metabolic networks to promote GC progression, suggesting the possibility of therapeutic intervention against cancer metabolic pathways.

MiR-488 suppresses cell proliferation and invasion by targeting ADAM9 and lncRNA HULC in hepatocellular carcinoma

MicroRNAs (miRNAs) have been identified as regulators of tumor proliferation, invasion, and metastasis in hepatocellular carcinoma (HCC). In the current study, we determined the clinical significance and biological role of miR-488 in HCC. Our results demonstrated that the expression of miR-488 was notably downregulated in HCC tissues compared with paired adjacent normal tissues. Lower miR-488 expression was positively associated with tumor size, vascular invasion, and shorter overall survival (OS) in HCC patients. Furthermore, gain-and-lost function assays showed that upregulation of miR-488 significantly inhibited cell proliferation, colony formation, cell invasion, and the epithelial-to-mesenchymal transition (EMT) process. We showed that ADAM9 served as a direct target for miR-488 and mediated lower miR-488 expression, thus inducing cell proliferation and invasion in HCC. Moreover, we found that lncRNA HULC is a target of miR-488 in HCC cells and miR-488 inhibited the expression of HULC by sponging to HULC in HCC. Thus, our results suggest that miR-488 functions as a tumor suppressor in HCC and may be a potential target for HCC treatment.

Identification of microRNAs as potential biomarkers for lung adenocarcinoma using integrating genomics analysis

Lung adenocarcinoma (LUAD) is the most common histological subtype of non-small cell lung cancer, but novel biomarkers for early diagnosis are lacking. Extensive effort has been exerted to identify miRNA biomarkers in LUAD. Unfortunately, high inter-lab variability and small sample sizes have produced inconsistent conclusions in this field. To resolve the above-mentioned limitations, we performed a comprehensive analysis based on LUAD miRNome profiling studies using the robust rank aggregation (RRA) method. Moreover, miRNA-gene interaction network, pathway enrichment analysis and Kaplan-Meier survival curves were used to investigate the clinical values and biological functions of the identified miRNAs. A total of six common differentially expressed miRNAs (DEMs) were identified in LUAD. An independent cohort further confirmed that four miRNAs (miR-21-5p, miR-210-3p, miR-182-5p and miR-183-5p) were up-regulated and two miRNAs (miR-126-3p and miR-218-5p) were down-regulated in LUAD tissues. Pathway enrichment analysis also suggested that the above-listed six DEMs may affect LUAD progression via the estrogen signaling pathway. Survival analysis based on the TCGA dataset revealed the potential prognostic values of six DEMs in patients with LUAD (P-value<0.01). In conclusion, we identified a panel of six miRNAs from LUAD using miRNome profiling studies. Our results provide evidence for the use of these six DEMs as novel diagnostic and prognostic biomarkers for LUAD patients.

Crosstalk in competing endogenous RNA network reveals the complex molecular mechanism underlying lung cancer

We investigated the transcriptional mechanism underlying lung cancer development. RNA sequencing analysis was performed on blood samples from lung cancer cases and healthy controls. Differentially expressed microRNAs (miRNAs), circular RNAs (circRNAs), mRNAs (genes), and long non-coding RNAs (lncRNA) were identified, followed by pathway enrichment analysis. Based on miRNA target interactions, a competing endogenous network was established and significant nodes were screened. Differentially expressed transcriptional factors were retrieved from the TRRUST database and the transcriptional factor regulatory network was constructed. The expression of 59 miRNAs, 18,306 genes,232 lncRNAs, and 292 circRNAs were greatly altered in patients with lung cancer. miRNAs were closely associated with cancer-related pathways, such as pathways in cancer, colorectal cancer, and transcriptional misregulation in cancer. Two novel pathways, olfactory transduction and neuroactive ligand-receptor interactions, were significantly enriched by differentially expressed genes. The competing endogenous RNA network revealed 5 hub miRNAs. Hsa-miR-582-3p and hsa-miR-582-5p were greatly enriched in the Wnt signaling pathway. Hsa-miR-665 was closely related with the MAPK signaling pathway. Hsa-miR-582-3p and hsa-miR-582-5p were also present in the TF regulatory network. Transcriptional factors of WT1 (wilms tumor 1) and ETV1 (ETS variant 1) were regulated by hsa-miR-657 and hsa-miR-582-5p, respectively, and controlled androgen receptor gene expression. miR-582-5p, miRNA-582-3p, and miR-657 may play critical regulatory roles in lung tumor development. Our work may explore new mechanism of lung cancer and aid the development of novel therapy.

ADAM9 expression promotes an aggressive lung adenocarcinoma phenotype

A disintegrin and metalloproteinase 9 (ADAM9) possesses potent metastasis-inducing capacities and is highly expressed in several cancer cells. Previous work has shown that ADAM9 participates in the adhesive-invasive phenotype in lung cancer cells in vitro. In this study, we evaluated whether ADAM9 expression plays a critical role in metastatic processes in vivo and in angiogenesis. We first found that high ADAM9 expression was correlated with poor lung adenocarcinoma patient prognosis on Prognoscan data base. In vivo model based on intravenous injection in nude mice showed that a stable downregulation of ADAM9 in A549 (TrA549 A9-) cells was associated with a lower number of nodules in the lung, suggesting lower potentials for extravasation and metastasis. On a subcutaneous xenograft we showed that TrA549 A9- produced significantly smaller tumours and exhibited fewer neovessels. In addition, in vitro human umbilical vein endothelial cells exposed to supernatant from TrA549 A9- could reduce the formation of more vessel-like structures. To further understand the mechanism, a human antibody array analysis confirmed that five cytokines were downregulated in TrA549 A9- cells. Interleukin 8 was the most significantly downregulated, and its interaction with CXCR2 was implicated in angiogenesis on an in vitro model. These results emphasize the critical influence of ADAM9 on lung cancer progression and aggressiveness. ADAM9 should at least be a marker of cancer aggressiveness and a potential therapeutic target for cancer treatment.

[MiR-218 Inhibits Migration and Invasion of Lung Cancer Cell by Regulating Robo1 Expression]

BACKGROUND

To explore the function and the potential molecular mechanism of miR-218 in lung cancer cell.

METHODS

The expression of miR-218 mRNA was determined by real-time PCR in lung cancer tissues, adjacent tissues and lung cancer cells. Transwell assay was used to detect the migration and invasion of A549 cell after transfected with Anti-miR-218 or negative control and HC4006 cell after transfected with miR-218 mimics and miR-218 negative control. Targetscan and MiRanda were used to calculate the potential targets of miR-218 and Luciferase reporter assay was performed to identify that the Robo1 was one target genes of miR-218. Transwell assay was used to detect whether miR-218 regulated the invasion of lung cancer cell transfected with anti-miR-218 or negative control via Robo1.

RESULTS

The expression of miR-218 in the lung cancer tissues was significantly lower than that in the adjacent tissues (P<0.05). Inhibition of miR-218 improved the migration and invasion of A549 cell. Overexpression of miR-218 suppressed the migration and invasion of HCC4006 cell. The co-transfection of anti-miR-218 or miR-218 mimics and the Robo1 3'UTR increased or reduced the luciferase activity of Robo1 compared with the control group (P<0.05). Inhibition of miR-218 and Robo1 recovered the invaded cells of A549. Overexpression of miR-218 and inhibition of Robo1 reduced the number of the invased cells of HCC4006. These results suggested that miR-218 banded Robo1 directly and inhibited lung cancer cell invasion by targeting Robo1.

CONCLUSIONS

MiR-218 inhibited the migration and invasion of lung cancer cells through regulating Robo1 expression.
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MARCKS promotes invasion and is associated with biochemical recurrence in prostate cancer

BACKGROUND

Overtreatment of low-grade prostate cancer is a recognised problem for clinicians and patients. However, under-treatment runs the risk of missing the opportunity for cure in those who could benefit. Identification of new biomarkers of disease progression, including metastases, is required to better stratify and appropriately treat these patients. The ability to predict if prostate cancer will recur is an important clinical question that would impact treatment options for patients. Studies in other cancers have associated MARCKS with metastasis.

METHODS

Tissue microarrays of local prostatectomy samples from a cohort of biochemical recurrent and non-biochemical recurrent tumours were assayed for MARCKS protein expression. Prostate cancer cell lines were transfected with siRNA targeting MARCKS or a control and functional endpoints of migration, invasion, proliferation, viability and apoptosis were measured. Actin was visualised by fluorescent microscopy and evidence of a cadherin switch and activation of the AKT pathway were assayed.

RESULTS

MARCKS was upregulated in biochemical recurrent patients compared to non-biochemical recurrent. Knockdown of MARCKS reduced migration and invasion of prostate cancer cells, reduced MMP9 mRNA expression, as well as decreasing cell spreading and increased cell:cell adhesion in prostate cancer cell colonies. Knockdown of MARCKS had no effect on proliferation, viability or apoptosis of the prostate cancer cells.

CONCLUSIONS

In conclusion, MARCKS promotes migration and invasion and is associated with biochemical recurrence in localised prostate cancer tumours. The mechanisms by which this occurs have yet to be fully elucidated but lack of a cadherin switch indicates it is not via epithelial-to-mesenchymal transition. Actin rearrangement indicates that MARCKS promotes invasion through regulating the architecture of the cell.

Dual effects of constitutively active androgen receptor and full-length androgen receptor for N-cadherin regulation in prostate cancer

Constitutively active androgen receptor (AR) variants have been involved in the expression of mesenchymal markers such as N-cadherin in prostate cancer (PCa). However, the underlying molecular mechanisms remain elusive. It remains unclear, whether N-cadherin gene (CDH2) is a direct transcriptional target of AR variants or whether the observed upregulation is due to indirect effects through additional regulatory factors. Moreover, the specific contribution of full-length AR and AR variants in N-cadherin regulation in PCa has never been explored deeply. To investigate this, we artificially mimicked the co-expression of AR variants together with a full-length AR and performed miRNA-seq, RNA-seq and ChIP assays. Our results were in favor of a direct AR variants action on CDH2. Our data also revealed a distinctive mode of action between full-length AR and AR variants to regulate N-cadherin expression. Both wild type AR and AR variants could interact with a regulatory element in intron 1 of CDH2. However, a higher histone H4 acetylation in this genomic region was only observed with AR variants. This suggests that full-length AR may play an occluding function to impede CDH2 upregulation. Our data further highlighted a negative effect of AR variants on the expression of the endogenous full-length AR in LNCaP. These differences in the mode of action of AR variants and full-length AR for the control of one key gene for prostate cancer progression could be worth considering for targeting AR variants in PCa.

Alternative new mesenchymal stem cell source exerts tumor tropism through ALCAM and N-cadherin via regulation of microRNA-192 and -218

Gliomas are the most common type of malignant primary brain tumors. Some treatments of gliomas exist, but they are rarely curative. Mesenchymal stem cells (MSCs) are emerging as potential modes of targeted cancer therapy owing to their capacity for homing toward tumor sites. It has been proposed that MSCs derived from various sources, such as bone marrow, adipose tissue and umbilical cord blood, can be used as cell-based therapy for brain tumors. Here, MSCs obtained from the synovial fluid of osteoarthritis or rheumatoid arthritis patients were investigated as therapeutic candidates. Specifically, we compared migratory and adhesive abilities, as well as expression levels of related genes and microRNA in bone marrow derived-MSCs (BMMSCs), adipose derived-MSCs (ADMSCs), and synovial fluid derived-MSCs (SFMSCs) after treatment with conditioned medium from gliomas. Migration and adhesion of SFMSCs increased through upregulation of the activated lymphocyte cell adhesion molecule (ALCAM) and N-cadherin by microRNA-192 and -218 downregulation, similar to BMMSCs and ADMSCs. Migratory capacities of all types of MSCs were evaluated in vivo, and SFMSCs migrated intensively toward gliomas. These results suggest that SFMSCs have potential for use in cell-based antitumor therapies.

Progression and metastasis of lung cancer

Metastasis in lung cancer is a multifaceted process. In this review, we will dissect the process in several isolated steps such as angiogenesis, hypoxia, circulation, and establishment of a metastatic focus. In reality, several of these processes overlap and occur even simultaneously, but such a presentation would be unreadable. Metastasis requires cell migration toward higher oxygen tension, which is based on changing the structure of the cell (epithelial-mesenchymal transition), orientation within the stroma and stroma interaction, and communication with the immune system to avoid attack. Once in the blood stream, cells have to survive trapping by the coagulation system, to survive shear stress in small blood vessels, and to find the right location for extravasation. Once outside in the metastatic locus, tumor cells have to learn the communication with the “foreign” stroma cells to establish vascular supply and again express molecules, which induce immune tolerance.

ADAM9 enhances CDCP1 protein expression by suppressing miR-218 for lung tumor metastasis

Metastasis is the leading cause of death in cancer patients due to the difficulty of controlling this complex process. MicroRNAs (miRNA), endogenous noncoding short RNAs with important biological and pathological functions, may play a regulatory role during cancer metastasis, but this role has yet to be fully defined. We previously demonstrated that ADAM9 enhanced the expression of the pro-migratory protein CDCP1 to promote lung metastasis; however, the regulatory process remains unknown. Here we demonstrate that endogenous miR-218, which is abundant in normal lung tissue but suppressed in lung tumors, is regulated during the process of ADAM9-mediated CDCP1 expression. Suppression of miR-218 was associated with high migration ability in lung cancer cells. Direct interaction between miR-218 and the 3'-UTR of CDCP1 mRNAs was detected in luciferase-based transcription reporter assays. CDCP1 protein levels decreased as expression levels of miR-218 increased, and increased in cells treated with miR-218 antagomirs. Induction of miR-218 inhibited tumor cell mobility, anchorage-free survival, and tumor-initiating cell formation in vitro and delayed tumor metastases in mice. Our findings revealed an integrative tumor suppressor function of miR-218 in lung carcinogenesis and metastasis.

miR-218 suppressed the growth of lung carcinoma by reducing MEF2D expression

Lung carcinoma is a deadly malignant disease with poor prognosis and increasing incidence in recent years. However, the molecular mechanism underlying the initiation and progression of lung cancer is still not completely elucidated. Recently, myocyte enhancer factor 2D (MEF2D) has been reported to promote the growth of liver cancer, but its implication in lung cancer is still unknown. This study is aimed to determine the role of MEF2D in lung carcinoma. Quantitative PCR (qPCR) and immunoblot assays showed that MEF2D was overexpressed in lung cancer tissues and cell lines, compared with the matched normal tissues and cell lines. Small interfering RNA (siRNA) suppression of MEF2D was able to reduce the proliferation, survival, and invasion of lung carcinoma cells. The transfection of MEF2D-expressing constructs into normal lung fibroblast cells promoted their proliferation and motility. The role of MEF2D in the growth of lung cancer was also confirmed in mice. Further study revealed that miR-218, which was underexpressed in lung carcinoma, was predicted to bind the 3'-untranslated region (UTR) of MEF2D mRNA. miR-218 was shown to suppress the activity of luciferase with MEF2D 3'-UTR. The changes in miR-218 levels affected the expression of MEF2D in lung cancer cells and normal fibroblast cells. There is also an inverse association between miR-218 abundance and MEF2D levels in the lung carcinoma specimen. Furthermore, the transfection of a plasmid that expressed MEF2D resistance to miR-218 regulation abolished the inhibitory effect of miR-218 on lung cancer cells. Collectively, MEF2D overexpression participated in the growth of lung cancers and its aberrant expression may result from the reduction of tumor suppressor miR-218.

Circulating microRNAs and long non-coding RNAs in gastric cancer diagnosis: An update and review

Gastric cancer (GC) is the fourth most common cancer and the third leading cause of cancer mortality worldwide. MicroRNAs (miRNAs) and long non-coding RNAs (lncRNAs) are the most popular non-coding RNAs in cancer research. To date, the roles of miRNAs and lncRNAs have been extensively studied in GC, suggesting that miRNAs and lncRNAs represent a vital component of tumor biology. Furthermore, circulating miRNAs and lncRNAs are found to be dysregulated in patients with GC compared with healthy individuals. Circulating miRNAs and lncRNAs may function as promising biomarkers to improve the early detection of GC. Multiple possibilities for miRNA secretion have been elucidated, including active secretion by microvesicles, exosomes, apoptotic bodies, high-density lipoproteins and protein complexes as well as passive leakage from cells. However, the mechanism underlying lncRNA secretion and the functions of circulating miRNAs and lncRNAs have not been fully illuminated. Concurrently, to standardize results of global investigations of circulating miRNAs and lncRNAs biomarker studies, several recommendations for pre-analytic considerations are put forward. In this review, we summarize the known circulating miRNAs and lncRNAs for GC diagnosis. The possible mechanism of miRNA and lncRNA secretion as well as methodologies for identification of circulating miRNAs and lncRNAs are also discussed. The topics covered here highlight new insights into GC diagnosis and screening.

RBMMMDA: predicting multiple types of disease-microRNA associations

Accumulating evidences have shown that plenty of miRNAs play fundamental and important roles in various biological processes and the deregulations of miRNAs are associated with a broad range of human diseases. However, the mechanisms underlying the dysregulations of miRNAs still have not been fully understood yet. All the previous computational approaches can only predict binary associations between diseases and miRNAs. Predicting multiple types of disease-miRNA associations can further broaden our understanding about the molecular basis of diseases in the level of miRNAs. In this study, the model of Restricted Boltzmann machine for multiple types of miRNA-disease association prediction (RBMMMDA) was developed to predict four different types of miRNA-disease associations. Based on this model, we could obtain not only new miRNA-disease associations, but also corresponding association types. To our knowledge, RBMMMDA is the first model which could computationally infer association types of miRNA-disease pairs. Leave-one-out cross validation was implemented for RBMMMDA and the AUC of 0.8606 demonstrated the reliable and effective performance of RBMMMDA. In the case studies about lung cancer, breast cancer, and global prediction for all the diseases simultaneously, 50, 42, and 45 out of top 100 predicted miRNA-disease association types were confirmed by recent biological experimental literatures, respectively.

MiR-218 inhibits HMGB1-mediated autophagy in endometrial carcinoma cells during chemotherapy

Endometrial carcinoma is the most common gynecological malignancy among women worldwide. Although treatment for EC has improved with the introduction of Paclitaxel (Tax) chemotherapy, the majority of patients will develop resistance to the treatment, leading to poor prognosis. One of the causes of chemoresistance is the increased ability to undergo autophagy. In this study, we identified that miR-218 was significantly down-regulated in Tax-resistant EC cells compared to the non-drug resistant cell lines, and overexpression of miR-218 sensitized paclitaxel resistant EC cells to paclitaxel. Moreover, we demonstrated that miR-218 directly binds to the 3'-UTR of HMGB1 gene. HMGB1 was upregulated in paclitaxel resistant EC cells, it mediated autophagy and contributed to chemotherapy resistance in endometrial carcinoma in vitro. HMGB1-mediated autophagy could be suppressed by miR-218 overexpression in Tax resistant EC cells. In summary, we determined the targeting role of miR-218 to HMGB1 and the regulation of miR-218 on the HMGB1-mediated cell autophagy during chemotherapy resistance in endometrial carcinoma cells. These results reveal novel potential role of miR-218 against chemotherapy resistance during the treatment of endometrial carcinoma.

Knockdown of PTTG1 inhibits the growth and invasion of lung adenocarcinoma cells through regulation of TGFB1/SMAD3 signaling

Increased expression of pituitary tumor-transforming gene 1 (PTTG1) is expressed in many tumors and regulates tumor growth and progression. However, the precise function of PTTG1 in the tumorigenesis of lung adenocarcinoma (LAC) is not defined yet. Here, we examined the expression of PTTG1 in human LAC tissues by immunohistochemical assay using a tissue microarray procedure. A loss-of-function experiment was carried out to investigate the effects of lentiviral vector-mediated PTTG1 shRNA (shPTTG1) on cell growth and invasive potential in LAC cell lines (A549 and LETPα-2), assessed by MTT and Transwell assays. As a consequence, we found that the expression of PTTG1 protein was markedly upregulated in LAC tissues compared with the adjacent non-cancerous tissues (ANCT) (54.0% vs. 28.0%, P = 0.008), and was positively associated with the lymphatic invasion of the tumor ( P = 0.01). Moreover, knockdown of PTTG1 expression inhibited tumor proliferation and invasion of LAC cells, companied by the decreased expression of CyclinD1 and MMP-2 and increased expression of p-TGFβ1 and p-SMAD3. Collectively, our findings indicate that high expression of PTTG1 is correlated with the tumor metastasis of LAC patients, and knockdown of PTTG1 suppresses the growth and invasion of LAC cells through upregulation of the TGFβ1/SMAD3 signaling, suggesting that PTTG1 may be a potential target for developing an effective immunotherapeutic strategy for LAC.

Differences in protein-protein association networks for lung adenocarcinoma: A retrospective study

Various methods to determine the connectivity scores between groups of proteins associated with lung adenocarcinoma are examined. Proteins act together to perform a wide range of functions within biological processes. Hence, identification of key proteins and their interactions within protein networks can provide invaluable information on disease mechanisms. Differential network analysis provides a means of identifying differences in the interactions among proteins between two networks. We use connectivity scores based on the method of partial least squares to quantify the strength of the interactions between each pair of proteins. These scores are then used to perform permutation-based statistical tests. This examines if there are significant differences between the network connectivity scores for individual proteins or classes of proteins. The expression data from a study on lung adenocarcinoma is used in this study. Connectivity scores are computed for a group of 109 subjects who were in the complete remission and as well as for a group of 51 subjects whose cancer had progressed. The distributions of the connectivity scores are similar for the two networks yet subtle but statistically significant differences have been identified and their impact discussed.

Altered interphase fluorescence in situ hybridization profiles of chromosomes 4, 8q24, and 9q34 in pancreatic ductal adenocarcinoma are associated with a poorer patient outcome

Most patients with pancreatic ductal adenocarcinoma (PDAC) die within 6 months of diagnosis. However, 20% to 25% patients undergoing total tumor resection remain alive and disease-free 5 years after diagnostic surgery. Few studies on tumor markers have predicted patient prognosis and/or survival. We evaluated the effect of tumor cytogenetic copy number changes detected by interphase fluorescence in situ hybridization on overall survival (OS) of 55 PDAC patients. The prognostic value of copy number changes showing an effect on OS was validated in an external cohort of 44 surgically resected PDAC patients by comparative genomic hybridization arrays, and the genes coded in altered chromosomes with prognostic value were identified by high-density single-nucleotide polymorphism arrays in 20 cases. Copy number changes of chromosomes 4 and 9q34 with gains of 8q24 were independently associated with shorter OS. On the basis of these three chromosomal alterations, a score is proposed that identifies patients with significantly different (P < 0.001) 5-year OS rates: 60% ± 20%, 16% ± 8%, and 0% ± 0%, respectively. Our results show an association between tumor cytogenetics and OS of PDAC patients and provide the basis for further prognostic stratification of patients undergoing complete tumor resection. Further studies to identify specific genes coded in these chromosomes and their functional consequences are necessary to understand the clinical effect of these changes.