microRNA-181a has a critical role in ovarian cancer progression through the regulation of the epithelial-mesenchymal transition

A HIF-1 network reveals characteristics of epithelial-mesenchymal transition in acute promyelocytic leukemia

Background

Acute promyelocytic leukemia (APL) is a sub-type of acute myeloid leukemia (AML) characterized by a block of myeloid differentiation at the promyelocytic stage and the predominant t(15:17) chromosomal translocation. We have previously determined that cells from APL patients show increased expression of genes regulated by hypoxia-inducible transcription factors (HIFs) compared to normal promyelocytes. HIFs regulate crucial aspects of solid tumor progression and are currently being implicated in leukemogenesis.

Methods

To investigate the contribution of hypoxia-related signaling in APL compared to other AML sub-types, we reverse engineered a transcriptional network from gene expression profiles of AML patients’ samples, starting from a list of direct target genes of HIF-1. A HIF-1-dependent subnetwork of genes specifically dysregulated in APL was derived from the comparison between APL and other AMLs.

Results

Interestingly, this subnetwork shows a unique involvement of genes related to extracellular matrix interaction and cell migration, with decreased expression of genes involved in cell adhesion and increased expression of genes implicated in motility and invasion, thus unveiling the presence of characteristics of epithelial-mesenchymal transition (EMT). We observed that the genes of this subnetwork, whose dysregulation shows a peculiar pattern across different AML sub-types, distinguish malignant from normal promyelocytes, thus ruling out dependence on a myeloid developmental stage. Also, expression of these genes is reversed upon treatment of APL-derived NB4 cells with all-trans retinoic acid and cell differentiation.

Conclusions

Our data suggest that pathways related to EMT-like processes can be implicated also in hematological malignancies besides solid tumors, and can identify specific AML sub-types.

Electronic supplementary material

The online version of this article (doi:10.1186/s13073-014-0084-4) contains supplementary material, which is available to authorized users.

Celecoxib induces epithelial-mesenchymal transition in epithelial ovarian cancer cells via regulating ZEB1 expression

PURPOSE

The purpose of our study was to investigate the therapeutic potential of Celecoxib for epithelial ovarian cancer, especially on cellular morphological changes, proliferation invasion and epithelial-mesenchymal transition (EMT).

METHOD

The MTT and transwell assays were performed to evaluate the effect of Celecoxib on proliferation and invasion ability of ovarian cancer cell lines, respectively. Western blot was carried out to detect the expression of epithelial phenotypes, E-cadherin and Keratin, and mesenchymal phenotypes, N-cadherin and Vimentin, as well as p-AKT, p-ERK and ZEB1. ZEB1 small-interfering RNA (siRNA) was used to downregulate the expression of ZEB1 to further inquiring into the downstream of Celecoxib-induced EMT.

RESULTS

Cellular morphological assessment revealed that both A2780 and SKOV3 cells gradually appeared in the morphology of mesenchymal cells after Celecoxib treatment. The MTT assay demonstrated that celecoxib had no effect on cell proliferation. Transwell assay showed that Celecoxib significantly increased the cell invasion ability. Western blot data proved that the expression of E-cadherin and keratin was elevated, whereas the expression of N-cadherin and Vimentin was decreased in a dose-dependent manner compared with the untreated cells, the expression of p-AKT, p-ERK and ZEB1 was also obviously elevated. However, ZEB1 siRNA reversed Celecoxib-induced E-cadherin expression and N-cadherin expression, as well as cellular invasiveness.

CONCLUSION

Our results indicated that Celecoxib might induce EMT and increase cellular invasiveness in ovarian cancer cells in vitro, which also implied that it needed a comprehensive evaluation in preclinical researches before introducing Celecoxib into the clinical regimen.

MiR-181a regulates blood-tumor barrier permeability by targeting Krüppel-like factor 6

Blood-tumor barrier (BTB) constitutes an efficient organization of tight junctions that impairs the delivery of therapeutic drugs. However, the methods and molecular mechanisms underlying the BTB opening remain elusive. MicroRNAs (miRNAs) have recently emerged as key regulators of various biologic processes and therapeutic targets. In this study, we have identified microRNA-181a (miR-181a) as a critical miRNA in opening BTB. MicroRNA-181a expression was upregulated in glioma endothelial cells (GECs), which were obtained by coculturing endothelial cells (ECs) with glioma cells. Overexpression of miR-181a resulted in an impaired and permeability increased BTB, and meanwhile reduced the expression of zonula occluden (ZO)-1, occludin, and claudin-5. Kruppel-like factor 6 (KLF6), a transcription factor of the zinc-finger family, was downregulated in GECs. Mechanistic investigations defined it as a direct and functional downstream target of miR-181a, which was involved in the regulation of BTB permeability and the expression of ZO-1, occludin, and claudin-5. Furthermore, luciferase assays and chromatin immunoprecipitation assays showed that KLF6 upregulated the promoter activities and interacted with the promoters of ZO-1, occludin, and claudin-5 in GECs. Collectively, we showed the possibility that overexpression of miR-181a contributes to the increased permeability of BTB by targeting KLF6, thereby revealing potential therapeutic targets for the treatment of brain gliomas.

MicroRNA as new tools for prostate cancer risk assessment and therapeutic intervention: results from clinical data set and patients' samples

Prostate cancer (PCa) is one of the leading causes of cancer-related death in men. Despite considerable advances in prostate cancer early detection and clinical management, validation of new biomarkers able to predict the natural history of tumor progression is still necessary in order to reduce overtreatment and to guide therapeutic decisions. MicroRNAs are endogenous noncoding RNAs which offer a fast fine-tuning and energy-saving mechanism for posttranscriptional control of protein expression. Growing evidence indicate that these RNAs are able to regulate basic cell functions and their aberrant expression has been significantly correlated with cancer development. Therefore, detection of microRNAs in tumor tissues and body fluids represents a new tool for early diagnosis and patient prognosis prediction. In this review, we summarize current knowledge about microRNA deregulation in prostate cancer mainly focusing on the different clinical aspects of the disease. We also highlight the potential roles of microRNAs in PCa management, while also discussing several current challenges and needed future research.

MiR-25 promotes ovarian cancer proliferation and motility by targeting LATS2

Ovarian cancer (OC) is a major cancer-related mortality among women. Recent studies suggest that many microRNAs (miRNAs) were dysregulated and involved in tumorigenesis of OC. The present study investigated the role of miR-25 in the development and progression of OC. The expression of miR-25 was increased in OC tissues and cell lines. Inhibition of miR-25 remarkably suppressed proliferation, migration, and invasion of OC cells. Large tumor suppressor 2 (LATS2), a tumor suppressor, was confirmed to be a direct target of miR-25 in OC cells. Moreover, restoration of LATS2 significantly attenuated the oncogenic effects of miR-25. Together, our data suggest an oncogenic role of miR-25 in OC and a potentially novel diagnostic and therapeutic target for OC treatment.

microRNA-128 plays a critical role in human non-small cell lung cancer tumourigenesis, angiogenesis and lymphangiogenesis by directly targeting vascular endothelial growth factor-C

Recent studies have indicated that microRNAs (miRNAs) are important gene regulators that play critical roles in biological processes and function as either tumour suppressors or oncogenes. Therefore, the expression levels of miRNAs can be important and reliable biomarkers for cancer detection and prognostic prediction, and potentially serve as targets for cancer therapy. In this study, we showed that the expression level of miR-128 was significantly downregulated in non-small cell lung cancer (NSCLC) tissues and cancer cells, and was significantly correlated with NSCLC differentiation, pathological stage and lymph node metastasis. Ectopic miR-128 overexpression significantly suppressed in vitro proliferation, colony formation, immigration and invasion, and induced G1 arrest and apoptosis of NSCLC cells. Interestingly, ectopic miR-128 overexpression could significantly inhibit vascular endothelial growth factor (VEGF)-C expression and reduce the activity of a luciferase reporter containing the VEGF-C 3'-untranslated region. In addition, overexpression of miR-128 in NSCLC cells and human umbilical vein endothelial cells (HUVECs) cells led to decreased expression of VEGF-A, vascular endothelial growth factor receptor (VEGFR)-2 and VEGFR-3, critical factors responsible for cancer angiogenesis and lymphangiogenesis, and subsequently decreased phosphorylation of extracellular signal-regulated kinase (ERK), phosphatidylinositol 3-kinase (AKT) and p38 signalling pathways. Furthermore, in vivo restoration of miR-128 significantly suppressed tumourigenicity of A549 cells in nude mice and inhibited both angiogenesis and lymphangiogenesis of tumour xenografts. These findings suggest that miR-128 could play a role in NSCLC tumourigenesis at least in part by modulation of angiogenesis and lymphangiogenesis through targeting VEGF-C, and could simultaneously block ERK, AKT and p38 signalling pathways. Therapeutic strategies to restore miR-128 in NSCLC could be useful to inhibit tumour progression.

Downregulation of NEK11 is associated with drug resistance in ovarian cancer

NEKs [NIMA (never in mitosis gene A)-related expressed kinase] are involved in ovarian cancer development and progression, while their association with drug resistance is limited, especially NEK11, and its relationship with drug resistance has never been reported. In this study, on the basis of comprehensive bioinformatic analyses, including mRNA expression according to microarray data, protein/gene interaction, protein-small molecule interaction, annotation of biological process and microRNA-mRNA interaction analysis, we revealed that the NEK11 mRNA was significantly downregulated in 586 cases of ovarian serous cystadenocarcinomas and cisplatin-resistant A2780 ovarian cancer cells, and interacted with 22 proteins and 4 small molecules which all were contributed to drug resistance in ovarian cancer. Furthermore, seven cell cycle-related biological processes were annotated with NEK11, drug resistance and ovarian cancer, suggesting that NEK11 potentially was involved in the drug resistance in ovarian cancer via its regulatory roles in the cell cycle. In addition, among the eight microRNAs predicted to be most strongly targeting NEK11, the majority were involved in drug resistance in ovarian and other cancers. All those results provide a very strong possibility that the notable downregulation of NEK11 in cisplatin-resistant ovarian cancer cells was involved in drug resistance, via its interactions with drug resistance-related genes, proteins, small molecules, microRNAs and biological processes, particularly the cell cycle-related processes. To our knowledge, this is the first report of the association of NEK11 with drug resistance in cancer, and it would pave the way for further investigation of the drug resistance-related functions of this gene.

SMAD7: a timer of tumor progression targeting TGF-β signaling

In the context of cancer, transforming growth factor β (TGF-β) is a cell growth suppressor; however, it is also a critical inducer of invasion and metastasis. SMAD is the important mediator of TGF-β signaling pathway, which includes receptor-regulated SMADs (R-SMADs), common-mediator SMADs (co-SMADs), and inhibitory SMADs (I-SMADs). I-SMADs block the activation of R-SMADs and co-SMADs and thus play important roles especially in the SMAD-dependent signaling. SMAD7 belongs to the I-SMADs. As an inhibitor of TGF-β signaling, SMAD7 is overexpressed in numerous cancer types and its abundance is positively correlated to the malignancy. Emerging evidence has revealed the switch-in-role of SMAD7 in cancer, from a TGF-β inhibiting protein at the early stages that facilitates proliferation to an enhancer of invasion at the late stages. This role change may be accompanied or elicited by the tumor microenvironment and/or somatic mutation. Hence, current knowledge suggests a tumor-favorable timer nature of SMAD7 in cancer progression. In this review, we summarized the advances and recent findings of SMAD7 and TGF-β signaling in cancer, followed by specific discussion on the possible factors that account for the functional changes of SMAD7.

MicroRNA-497 inhibition of ovarian cancer cell migration and invasion through targeting of SMAD specific E3 ubiquitin protein ligase 1

Ovarian cancer is the leading cause of death from gynecological malignancies worldwide. Understanding the molecular mechanism underlying ovarian cancer progression facilitates the development of promising strategy for ovarian cancer therapy. Previously, we observed frequent down-regulation of miR-497 expression in ovarian cancer tissues. In this study, we investigated the role of miR-497 in ovarian cancer metastasis. We found that endogenous miR-497 expression was down-regulated in the more aggressive ovarian cancer cell lines compared with the less aggressive cells. Exogenous expression of miR-497 suppressed ovarian cancer cell migration and invasion, whereas reduction of endogenous miR-497 expression induced tumor cell migration and invasion. Mechanistic investigations confirmed pro-metastatic factor SMURF1 as a direct target of miR-497 through which miR-497 ablated tumor cell migration and invasion. Further studies revealed that lower levels of miR-497 expression were associated with shorter overall survival as well as increased SMURF1 expression in ovarian cancer patients. Our results indicate that down-regulation of miR-497 in ovarian cancer may facilitate tumor metastasis. Restoration of miR-497 expression may be a promising strategy for ovarian cancer therapy.

The expression and clinical significance of miR-132 in gastric cancer patients

Background and objective

miR-132 plays a role in regulating neuronal morphology and cellular excitability. Little is known about the effects of miR-132 in cancer. The aim of this study is to evaluate the expression of miR-132 and its clinical significance in gastric cancer.

Methods

Cancerous tissues and corresponding normal tissues from 79 patients with gastric cancer were examined for the expression of miR-132 using quantitative PCR and the association between miR-132 expression levels and clinicopathological factors and prognosis was analyzed.

Results

In 79 clinical samples of gastric cancer patients, miR-132 expression levels in cancer tissues were significantly higher than those in the corresponding normal tissues (P = 0.001). Higher expression levels of miR-132 were associated with more frequent lymph node metastasis (P = 0.033), more lymphatic tumor emboli (P = 0.007), and more advanced stage (P = 0.016). Additionally, expression of miR-132 was an independent prognostic factor for overall survival (P = 0.020).

Conclusion

miR-132 could serve as an efficient prognostic factor for gastric cancer patients.

Virtual slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/8168577241196050

Therapeutic Opportunities for Targeting microRNAs in Cancer

MicroRNAs (miRNAs) are small noncoding RNAs that can function as either powerful tumor promoters or suppressors in numerous types of cancer. The ability of miRs to target multiple genes and biological signaling pathways has created intense interest in their potential clinical utility as predictive and diagnostic biomarkers, and as innovative therapeutic agents. Recently, accumulating preclinical studies have illustrated the feasibility of slowing tumor progression by either overexpressing tumor suppressive miRNAs, or by neutralizing the activities of oncogenic miRNAs in cell- and animal-based models of cancer. Here we highlight prominent miRNAs that may represent potential therapeutic targets in human malignancies, as well as review current technologies available for inactivating or restoring miRNA activity in clinical settings.