microRNA-590 suppresses the tumorigenesis and invasiveness of non-small cell lung cancer cells by targeting ADAM9

MicroRNAs and proteolytic cleavage of receptors in cancers: A comprehensive review of regulatory interactions and therapeutic implications

Cancer remains a challenging disease worldwide, necessitating innovative approaches to better comprehend its underlying molecular mechanisms and devise effective therapeutic strategies. Over the past decade, microRNAs (miRNAs) have emerged as crucial players in cancer progression due to their regulatory roles in various cellular processes. Moreover, the involvement of unwanted soluble receptors has gained increasing attention because they contribute to tumorigenesis or drug resistance by disrupting normal signaling pathways and neutralizing ligands. This comprehensive review explores the intricate interplay between miRNAs and unwanted-soluble receptors in the context of cancer biology. This study provides an analysis of the regulatory interactions between miRNAs and these receptors, elucidating how miRNAs can either suppress or enhance their expression. MiRNAs can directly target receptor transcripts, thereby regulating soluble receptor levels. They also modulate the proteolytic cleavage of membrane-bound receptors into soluble forms by targeting sheddases, such as ADAMs and MMPs. Furthermore, the review delves into the therapeutic potential of manipulating miRNAs to modulate unwanted soluble receptors. Various strategies, including synthetic miRNA mimics or anti-miRNAs, hold promise for restoring or inhibiting miRNA function to counteract aberrant receptor activity. Moreover, exploring miRNA-based delivery systems may provide targeted and precise therapies that minimizing off-target effects. In conclusion, this review sheds light on the intricate regulatory networks involving miRNAs and unwanted soluble receptors in cancer biology thereby uncovering novel therapeutic targets, and paving the way for developing innovative anti-cancer therapies.

Exploring the oncogenic and tumor-suppressive roles of Circ-ADAM9 in cancer

Circular RNAs (circRNAs) constitute a recently identified category of closed continuous loop RNA transcripts, serving as a subset of competing endogenous RNAs (ceRNAs) with the capacity to modulate genes by acting as microRNA sponges. In the context of cancer growth, numerous investigations have explored the potential functions of circRNAs, revealing their diverse functions either as oncogenes, promoting cancer progression, or as tumor suppressors, mitigating disease development. Among these, circRNA ADAM9 (Circ-ADAM9) is now recognized as an important player in a variety of mechanisms, both physiological and pathological, especially in cancer. The aberrant expression of Circ-ADAM9 has been observed across multiple human malignancies, implying a significant involvement in tumorigenesis. This comprehensive review aims to synthesize recent findings elucidating the function of Circ-ADAM9 in many malignancies. Additionally, the review explores the possibility of Circ-ADAM9 as a valuable biomarker, offering insights into its prognostic, diagnostic, and therapeutic implications. By summarizing the latest discoveries in this field, the review contributes to our understanding of the multifaceted contribution of Circ-ADAM9 in tumor biology and its potential applications in clinical settings.

Advances in Brain Metastases Diagnosis: Non-coding RNAs As Potential Biomarkers

Brain metastasis is considered the most common brain tumor. They arise from different primary cancers. The most common primary tumors giving brain metastases include breast, colorectal, lung, melanoma, and renal cancer. Depending only on history, physical examination, and conventional imaging modalities makes brain tumors diagnosis difficult. Rapid and non-invasive promising modalities could diagnose and differentiate between different brain metastases without exposing the patients to unnecessary brain surgeries for biopsies. One of these promising modalities is non-coding RNAs (ncRNAs). NcRNAs can determine brain metastases' prognosis, chemoresistance, and radioresistance. It also helps us to understand the pathophysiology of brain metastases development. Additionally, ncRNAs may work as potential therapeutic targets for brain metastases treatment and prevention. Herein, we present deregulated ncRNAs in different brain metastases, including microRNAs and long non-coding RNAs (lncRNAs), such as gastric adenocarcinoma, colorectal, breast, melanoma, lung, and prostate cancer. Additionally, we focus on serum and cerebrospinal fluid (CSF) expression of these ncRNAs in patients with brain metastases compared to patients with primary tumors. Moreover, we discuss the role of ncRNAs in modulating the immune response in the brain microenvironment. More clinical studies are encouraged to assess the specificity and sensitivity of these ncRNAs.

Spectrum of microRNAs and their target genes in cancer: intervention in diagnosis and therapy

Till date, several groups have studied the mechanism of microRNA (miRNA) biogenesis, processing, stability, silencing, and their dysregulation in cancer. The miRNA coding genes recurrently go through abnormal amplification, deletion, transcription, and epigenetic regulation in cancer. Some miRNAs function as tumor promoters while few others are tumor suppressors based on the transcriptional regulation of target genes. A review of miRNAs and their target genes in a wide range of cancers is attempted in this article, which may help in the development of new diagnostic tools and intervention therapies. The contribution of miRNAs for drug sensitivity or resistance in cancer therapy and opportunities of miRNAs in cancer prognosis or diagnosis and therapy is also presented in detail.

Cancer driver gene and non-coding RNA alterations as biomarkers of brain metastasis in lung cancer: A review of the literature

Brain metastasis (BM) is the most common event in patients with lung cancer. Despite multimodal treatments and advances in systemic therapies, development of BM remains one of the main factors associated with poor prognosis and mortality in patients with lung cancer. Therefore, better understanding of mechanisms involved in lung cancer brain metastasis (LCBM) is of great importance to suppress cancer cells and to improve the overall survival of patients. Several cancer-related genes such as EGFR and KRAS have been proposed as potential predictors of LCBM. In addition, there is ample evidence supporting crucial roles of non-coding RNAs (ncRNAs) in mediating LCBM. In this review, we provide comprehensive information on risk assessment, predictive, and prognostic panels for early detection of BM in patients with lung cancer. Moreover, we present an overview of LCBM molecular mechanisms, cancer driver genes, and ncRNAs which may predict the risk of BM in lung cancer patients. Recent clinical studies have focused on determining mechanisms involved in LCBM and their association with diagnosis, prognosis, and treatment outcomes. These studies have shown that alterations in EGFR, KRAS, BRAF, and ALK, as the most frequent coding gene alterations, and dysregulation of ncRNAs such as miR-423, miR-330-3p, miR-145, piR-651, and MALAT1 can be considered as potential biomarkers of LCBM.

Narrative review: molecular and genetic profiling of oligometastatic non-small cell lung cancer

Objective

The objectives of this review are to discuss: the definition, clinical and biologic features of oligometastatic non-small cell lung cancer (NSCLC), as well as the concept of treating oligoprogression in oligometastatic NSCLC.

Background

A substantial proportion of patients diagnosed with lung cancer present with metastatic disease, and a large portion of patients who present with localized disease later develop metastases. Oligometastatic NSCLC is defined as an intermediate state between localized and widespread metastatic disease, where there may be a role for curative localized therapy approach by treating the primary tumor and all metastases with radiotherapy or surgery. Despite the increasing application of this approach in patients with lung cancer, the identification of patients who might benefit from this approach is yet to be well characterized.

Methods

After a systematic review of the literature, a PubMed search was performed using the English language and the key terms: oligometastatic, non-small cell lung cancer (NSCLC), localized consolidative treatment (LCT), biomarkers, biologic features, clinical features. Over 500 articles were retrieved between 1889–2021. A total of 178 papers discussing the definition, clinical and biologic factors leading to oligometastatic NSCLC were reviewed and included in the discussion of this paper.

Conclusions

Oligometastatic NSCLC is a unique entity. Identifying patients who have oligometastatic NSCLC accurately using a combination of clinical and biologic features and treating them with localized consolidative approach appropriately results in improvement of outcome. Further understanding of the molecular mechanisms driving the formation of oligometastatic NSCLC is an important area of focus for future studies.

microRNA-1298 inhibits the malignant behaviors of breast cancer cells via targeting ADAM9

MicroRNAs (miRNAs) regulate the progression of human malignancy by targeting oncogenes or tumor suppressors, which are 12 promising targets for cancer treatment. Increasing evidence has suggested the aberrant expression and tumor-suppressive function of miR-1298 in cancers, however, the regulatory mechanism of miR-1298 in breast cancer (BC) remains unclear. Here, our findings showed that miR-1298 was down-regulated in BC tissues and cell lines. Lower level of miR-1298 was significantly correlated with the advanced progression of BC patients. Experimental study showed that overexpression of miR-1298 inhibited the proliferation, induced apoptosis and cell cycle arrest in BC cells. The in vivo xenograft mice model showed that highly expressed miR-1298 significantly reduced the tumor growth and metastasis. Further mechanism analysis revealed that miR-1298 bound the 3′-untranslated region (UTR) of a disintegrin and metalloproteinase 9 domain (ADAM9) and suppressed the expression of ADAM9 in BC cells. ADAM9 was overexpressed in BC tissues and inversely correlated with miR-1298. Down-regulation of ADAM9 induced apoptosis and cell cycle arrest of BC cells. Moreover, ectopic expression of ADAM9 by transiently transfecting with vector encoding the full coding sequence of ADAM9 attenuated the inhibitory effects of miR-1298 on the proliferation and cell cycle progression of BC cells. Collectively, our results illustrated that miR-1298 played a suppressive role in regulating the phenotype of BC cells through directly repressing ADAM9, suggesting the potential application of miR-1298 in the therapy of BC.

Exosomal miR-590-5p in Serum as a Biomarker for the Diagnosis and Prognosis of Gastric Cancer

The purpose of this study is to explore the expression of miRNA-590-5p, an exosome of gastric cancer (GC), and to evaluate the suitability of miR-590-5p, an exosome with its own clinical characteristics. Serum samples from 168 gastric cancer patients and 50 matched controls were collected and exosomal RNAs were extracted. After that, miR-590-5p is analyzed by quantitative polymerase chain reaction (qRT-PCR), which is more related to clinical and pathological parameters and patient monitoring data. MGC-803 and HGC-27 cells were treated by miR-590-5p mimics, and then the changes of cell fluidity and invasiveness were monitored. The results showed that the expression level of miR-590-5p in exosomes of healthy observation group, early (I and II) stage group, and late stage (III) group was 30.34 ± 6.35, 6.19 ± 0.81, and 2.9 ± 0.19, respectively (all p < 0.05). ROC (receiver-operating characteristic curve) showed that the AUC (area under the curve) of exosomal miR-590-5p was 0.810 with 63.7% sensitivity and 86% specificity. The expression of exosomal miR-590-5p in serum was related to clinical stage (p = 0.008), infiltration depth, and the expression level of ki-67 (p < 0.001). In addition, Kaplan-Meier analysis showed that the decrease of explicit level of exosomal miR-590-5p was related to the decrease of overall survival rate (p < 0.001). Cox regression analysis showed that miR-590-5p can be used as an independent predictor. Furthermore, upregulation of miR-590-5p inhibited cell migration and invasion in MGC-803 cells and HGC-27 cells. The serum expression level of exosomal miR-590-5p may be a biomarker, which is potentially useful and noninvasive for early detection and prediction of GC. In addition, miR-590-5p can play a role in eliminating carcinogens by actively regulating the malignant potential of gastric cancer.

An Overview of ADAM9: Structure, Activation, and Regulation in Human Diseases

ADAM9 (A disintegrin and a metalloprotease 9) is a membrane-anchored protein that participates in a variety of physiological functions, primarily through the disintegrin domain for adhesion and the metalloprotease domain for ectodomain shedding of a wide variety of cell surface proteins. ADAM9 influences the developmental process, inflammation, and degenerative diseases. Recently, increasing evidence has shown that ADAM9 plays an important role in tumor biology. Overexpression of ADAM9 has been found in several cancer types and is correlated with tumor aggressiveness and poor prognosis. In addition, through either proteolytic or non-proteolytic pathways, ADAM9 promotes tumor progression, therapeutic resistance, and metastasis of cancers. Therefore, comprehensively understanding the mechanism of ADAM9 is crucial for the development of therapeutic anti-cancer strategies. In this review, we summarize the current understanding of ADAM9 in biological function, pathophysiological diseases, and various cancers. Recent advances in therapeutic strategies using ADAM9-related pathways are presented as well.

MicroRNA‑590 inhibits migration, invasion and epithelial‑to‑mesenchymal transition of esophageal squamous cell carcinoma by targeting low‑density lipoprotein receptor‑related protein 6

MicroRNA-590 (miR-590) has been revealed as a tumor suppressor, while low-density lipoprotein receptor-related protein 6 (LRP6) is considered to act as a tumor promoter. However, their roles and underlying molecular regulatory mechanisms in esophageal squamous cell carcinoma (ESCC) have yet to be fully elucidated. Therefore, the present study aimed to investigate these mechanisms. The expression levels of miR-590 and LRP6 in human ESCC samples and cell lines were determined using reverse transcription-quantitative PCR. Bioinformatics analysis was used to predict the relationship between miR-590 and LRP6, and luciferase assay was performed to validate the relationship between these factors. Transwell assays were used to determine cell migration and invasion, while western blotting assays were used to detect the protein expression levels of LRP6, E-cadherin, N-cadherin and Vimentin. The present study demonstrated that miR-590 was downregulated and LRP6 was upregulated in ESCC tissues and cell lines. Furthermore, it was found that miR-590 overexpression and LRP6 knockdown inhibited cell migration, invasion and epithelial-to-mesenchymal transition (EMT) in ESCC cell lines. Additional mechanistic studies identified that LRP6 was a target of, and was inhibited by, miR-590. Collectively, the present findings suggested that miR-590 inhibited the invasion, migration and EMT of ESCC cells by mediating LRP6.

Downregulation of SOX2 may be targeted by miR-590-5p and inhibits epithelial-to-mesenchymal transition in non-small-cell lung cancer

Non-small-cell lung cancer (NSCLC) is the leading type of cancer worldwide and sex determining region Y-box 2 (SOX2) has been implicated as an oncogene in various types of cancer. In the present study, SOX2 was positively associated with NSCLC stage and lymph node metastasis. Wound healing and Transwell assays demonstrated that knockdown of SOX2 inhibited A549 and H1299 cell migration. Furthermore, it was identified that knockdown of SOX2 inhibited epithelial-to-mesenchymal transition of NSCLC cells, which was demonstrated by increased expression of epithelial-cadherin and decreased expression of vimentin, zinc finger protein SNAI1 and zinc finger protein SNAI2. It was then demonstrated that SOX2 may be targeted by microRNA (miR)-590-5p, which indicated a potential therapeutic strategy for NSCLC focusing on the miR-590-5p/SOX2 axis.

MicroRNA in Lung Cancer Metastasis

Tumor metastasis is a hallmark of cancer, with distant metastasis frequently developing in lung cancer, even at initial diagnosis, resulting in poor prognosis and high mortality. However, available biomarkers cannot reliably predict cancer spreading sites. The metastatic cascade involves highly complicated processes including invasion, migration, angiogenesis, and epithelial-to-mesenchymal transition that are tightly controlled by various genetic expression modalities along with interaction between cancer cells and the extracellular matrix. In particular, microRNAs (miRNAs), a group of small non-coding RNAs, can influence the transcriptional and post-transcriptional processes, with dysregulation of miRNA expression contributing to the regulation of cancer metastasis. Nevertheless, although miRNA-targeted therapy is widely studied in vitro and in vivo, this strategy currently affords limited feasibility and a few miRNA-targeted therapies for lung cancer have entered into clinical trials to date. Advances in understanding the molecular mechanism of metastasis will thus provide additional potential targets for lung cancer treatment. This review discusses the current research related to the role of miRNAs in lung cancer invasion and metastasis, with a particular focus on the different metastatic lesions and potential miRNA-targeted treatments for lung cancer with the expectation that further exploration of miRNA-targeted therapy may establish a new spectrum of lung cancer treatments.

MicroRNA in lung cancer: role, mechanisms, pathways and therapeutic relevance

Lung cancer is the cardinal cause of cancer-related deaths with restricted recourse of therapy throughout the world. Clinical success of therapies is not very promising due to - late diagnosis, limited therapeutic tools, relapse and the development of drug resistance. Recently, small ∼20-24 nucleotides molecules called microRNAs (miRNAs) have come into the limelight as they play outstanding role in the process of tumorigenesis by regulating cell cycle, metastasis, angiogenesis, metabolism and apoptosis. miRNAs essentially regulate gene expression via post-transcriptional regulation of mRNA. Nevertheless, few studies have conceded the role of miRNAs in activation of gene expression. A large body of data generated by numerous studies is suggestive of their tumor-suppressing, oncogenic, diagnostic and prognostic biomarker roles in lung cancer. They have also been implicated in regulating cancer cell metabolism and resistance or sensitivity towards chemotherapy and radiotherapy. Further, miRNAs have also been convoluted in regulation of immune checkpoints - Programmed death 1 (PD-1) and its ligand (PD-L1). These molecules play a significant role in tumor immune escape leading to the generation of a microenvironment favouring tumor growth and progression. Therefore, it is imperative to explore the expression of miRNA and understand its relevance in lung cancer and development of anti-cancer strategies (anti - miRs, miR mimics and micro RNA sponges). In view of the above, the role of miRNA in lung cancer has been dissected and the associated mechanisms and pathways are discussed in this review.

FGF18, a prominent player in FGF signaling, promotes gastric tumorigenesis through autocrine manner and is negatively regulated by miR-590-5p

Fibroblast growth factors (FGFs) and their receptors are significant components during fundamental cellular processes. FGF18 plays a distinctive role in modulating the activity of both tumor cells and tumor microenvironment. This study aims to comprehensively investigate the expression and functional role of FGF18 in gastric cancer (GC) and elucidate its regulatory mechanisms. The upregulation of FGF18 was detected in seven out of eleven (63.6%) GC cell lines. In primary GC samples, FGF18 was overexpressed in genomically stable and chromosomal instability subtypes of GC and its overexpression was associated with poor survival. Knocking down FGF18 inhibited tumor formation abilities, induced G1 phase cell cycle arrest and enhanced anti-cancer drug sensitivity. Expression microarray profiling revealed that silencing of FGF18 activated ATM pathway but quenched TGF-β pathway. The key factors that altered in the related signaling were validated by western blot and immunofluorescence. Meanwhile, treating GC cells with human recombinant FGF18 or FGF18-conditioned medium accelerated tumor growth through activation of ERK-MAPK signaling. FGF18 was further confirmed to be a direct target of tumor suppressor, miR-590-5p. Their expressions showed a negative correlation in primary GC samples and more importantly, re-overexpression of FGF18 partly abolished the tumor-suppressive effect of miR-590-5p. Our study not only identified that FGF18 serves as a novel prognostic marker and a therapeutic target in GC but also enriched the knowledge of FGF-FGFR signaling during gastric tumorigenesis.

MicroRNA-138 inhibits SOX12 expression and the proliferation, invasion and migration of ovarian cancer cells

The aim of the present study was to investigate the expression and biological functions of microRNA (miR)-138 in ovarian cancer at the tissue and cellular levels, as well as its underlying mechanisms. A total of 47 patients with ovarian cancer were included in the present study. Ovarian cancer tissues were subjected to staging classification according to the FIGO 2000 criteria. Lymphatic metastasis was also examined. Ovarian cancer A2780 cells were transfected using liposomes. Reverse transcription-quantitative polymerase chain reaction was used to measure the expression of miR-138. A Cell-Counting Kit 8 assay was used to examine cell viability, while a Transwell assay was employed to study cell invasion and migration. The effects of miR-138 on SOX12 protein expression were examined by western blot analysis. A dual luciferase reporter assay was performed to identify the direct interaction between miR-138 and SOX12 gene. Expression of miR-138 was downregulated in ovarian cancer tissues. The level of miR-138 in patients with ovarian cancer with lymphatic metastasis was significantly lower compared with patients without lymphatic metastasis. However, expression of miR-138 was not associated with the stage of ovarian cancer. Upregulation of miR-138 inhibited the proliferation and suppressed the invasion and migration of A2780 cells. SOX12 promoted the proliferation, invasion and migration of A2780 cells. In addition, miR-138 downregulated the expression of SOX12 via binding with the 3′-UTR of SOX12 gene. The present study demonstrates that miR-138 expression is downregulated in ovarian cancer tissues and miR-138 acts as a tumor suppressor gene by inhibiting SOX12 expression and the proliferation, invasion and migration of ovarian cancer cells.

MiR-1297 suppresses pancreatic cancer cell proliferation and metastasis by targeting MTDH

Dysregulation of miR-1297 has been detected in various human cancers, and miR-1297 can function as either an oncogene or tumor suppressor. However, the role of miR-1297 in pancreatic adenocarcinoma has not been previously reported. Here, we investigated miR-1297 expression in pancreatic cancer and the role it plays in the development and metastasis of pancreatic adenocarcinoma. In the present study, MiR-1297 and metadherin (MTDH) expression in pancreatic cancer tissue was detected using quantitative real-time PCR (qRT-PCR) and western blot methods. The CCK-8 assay and EdU incorporation assay were used to analyze the impact of miR-1297 and MTDH on cell proliferation. Flow cytometric and Hoechst 33342 staining methods were used to explore how miR-1297 and MTDH affect cell apoptosis. The Transwell assay and scratch wound healing assay were used to analyze cell migration and invasion capabilities. The dual-luciferase assay was used to confirm that miR-1297 targets MTDH. Here, we found that miR-1297 expression was decreased in pancreatic adenocarcinoma tissues, while MTDH expression was increased in those tissues. Furthermore, western blot and dual-luciferase assay results confirmed that MTDH was a direct target of miR-1297. Additionally, overexpression of miR-1297 or knockdown of MTDH suppressed BxPC-3 and PANC-1 cell proliferation, and upregulation of miR-1297 or suppression of MTDH promoted BxPC-3 and PANC-1 cell apoptosis. Finally, BxPC-3 and PANC-1 cell migration and invasion abilities were suppressed by either overexpression of miR-1297 or downregulation of MTHD. In conclusion, our results suggest that miR-1297 inhibits the growth and metastasis of pancreatic adenocarcinoma by downregulating MTDH expression, and the miR-1297/MTDH pathway is a potential target for treating pancreatic adenocarcinoma.

ADAM9 mediates the interleukin-6-induced Epithelial-Mesenchymal transition and metastasis through ROS production in hepatoma cells

Interleukin (IL)-6 has been implicated in the invasion and metastasis of hepatocellular carcinoma (HCC). However, the molecular events that mediate this process are poorly understood. Here, we showed that IL-6 promoted the epithelial-mesenchymal transition (EMT) in HCC cell lines, and upregulated a disintegrin and metalloprotease 9 (ADAM9) expression by activating the JNK signaling pathway. ADAM9 was upregulated in human HCCs which promoted HCC cell invasion and the EMT by interacting with NADPH oxidase 1 and inducing reactive oxygen species generation. Knockdown of ADAM9 inhibited the IL-6-induced EMT. Additionally, ADAM9 expression was positively correlated with IL-6 and Snail expression in human HCC specimens. Taken together, our results showed that ADAM9 is an important mediator of IL-6-induced HCC cell migration and invasion, and may provide a novel therapeutic target for HCC management.

Loss of ADAM9 expression impairs β1 integrin endocytosis, focal adhesion formation and cancer cell migration

The transmembrane protease ADAM9 is frequently upregulated in human cancers, and it promotes tumour progression in mice. In vitro, ADAM9 regulates cancer cell adhesion and migration by interacting with integrins. However, how ADAM9 modulates integrin functions is not known. We here show that ADAM9 knockdown increases β1 integrin levels through mechanisms that are independent of its protease activity. In ADAM9-silenced cells, adhesion to collagen and fibronectin is reduced, suggesting an altered function of the accumulated integrins. Mechanistically, ADAM9 co-immunoprecipitates with β1 integrin, and both internalization and subsequent degradation of β1 integrin are significantly decreased in ADAM9-silenced cells, with no effect on β1 integrin recycling. Accordingly, the formation of focal adhesions and actin stress fibres in ADAM9-silenced cells is altered, possibly explaining the reduction in cell adhesion and migration in these cells. Taken together, our data provide mechanistic insight into the ADAM9-integrin interaction, demonstrating that ADAM9 regulates β1 integrin endocytosis. Moreover, our findings indicate that the reduced migration of ADAM9-silenced cells is, at least in part, caused by the accumulation and altered activity of β1 integrin at the cell surface.

ADAM9 promotes lung cancer progression through vascular remodeling by VEGFA, ANGPT2, and PLAT

Lung cancer has a very high prevalence of brain metastasis, which results in a poor clinical outcome. Up-regulation of a disintegrin and metalloproteinase 9 (ADAM9) in lung cancer cells is correlated with metastasis to the brain. However, the molecular mechanism underlying this correlation remains to be elucidated. Since angiogenesis is an essential step for brain metastasis, microarray experiments were used to explore ADAM9-regulated genes that function in vascular remodeling. The results showed that the expression levels of vascular endothelial growth factor A (VEGFA), angiopoietin-2 (ANGPT2), and tissue plasminogen activator (PLAT) were suppressed in ADAM9-silenced cells, which in turn leads to decreases in angiogenesis, vascular remodeling, and tumor growth in vivo. Furthermore, simultaneous high expression of ADAM9 and VEGFA or of ADAM9 and ANGPT2 was correlated with poor prognosis in a clinical dataset. These findings suggest that ADAM9 promotes tumorigenesis through vascular remodeling, particularly by increasing the function of VEGFA, ANGPT2, and PLAT.

MicroRNA-138 Inhibits Cell Growth, Invasion, and EMT of Non-Small Cell Lung Cancer via SOX4/p53 Feedback Loop

Many studies have shown that downregulation of miR-138 occurs in a variety of cancers including non-small cell lung cancer (NSCLC). However, the precise mechanisms of miR-138 in NSCLC have not been well clarified. In this study, we investigated the biological functions and molecular mechanisms of miR-138 in NSCLC cell lines, discussing whether it could turn out to be a therapeutic biomarker of NSCLC in the future. In our study, we found that miR-138 is downregulated in NSCLC tissues and cell lines. Moreover, the low level of miR-138 was associated with increased expression of SOX4 in NSCLC tissues and cell lines. Upregulation of miR-138 significantly inhibited proliferation of NSCLC cells. In addition, invasion and EMT of NSCLC cells were suppressed by overexpression of miR-138. However, downregulation of miR-138 promoted cell growth and metastasis of NSCLC cells. Bioinformatics analysis predicted that SOX4 was a potential target gene of miR-138. Next, luciferase reporter assay confirmed that miR-138 could directly target SOX4. Consistent with the effect of miR-138, downregulation of SOX4 by siRNA inhibited proliferation, invasion, and EMT of NSCLC cells. Overexpression of SOX4 in NSCLC cells partially reversed the effect of miR-138 mimic. In addition, decreased SOX4 expression could increase the level of miR-138 via upregulation of p53. Introduction of miR-138 dramatically inhibited growth, invasion, and EMT of NSCLC cells through a SOX4/p53 feedback loop.

Characterization of the catalytic properties of the membrane-anchored metalloproteinase ADAM9 in cell-based assays

ADAM9 (A Disintegrin And Metalloprotease 9) is a membrane-anchored metalloproteinase that has been implicated in pathological retinal neovascularization and in tumor progression. ADAM9 has constitutive catalytic activity in both biochemical and cell-based assays and can cleave several membrane proteins, including epidermal growth factor and Ephrin receptor B4; yet little is currently known about the catalytic properties of ADAM9 and its post-translational regulation and inhibitor profile in cell-based assays. To address this question, we monitored processing of the membrane-anchored Ephrin receptor B4 (EphB4) by co-expressing ADAM9, with the catalytically inactive ADAM9 E > A mutant serving as a negative control. We found that ADAM9-dependent shedding of EphB4 was not stimulated by three commonly employed activators of ADAM-dependent ectodomain shedding: phorbol esters, pervanadate or calcium ionophores. With respect to the inhibitor profile, we found that ADAM9 was inhibited by the hydroxamate-based metalloprotease inhibitors marimastat, TAPI-2, BB94, GM6001 and GW280264X, and by 10 nM of the tissue inhibitor of metalloproteinases (TIMP)-3, but not by up to 20 nM of TIMP-1 or -2. Additionally, we screened a non-hydroxamate small-molecule library for novel ADAM9 inhibitors and identified four compounds that selectively inhibited ADAM9-dependent proteolysis over ADAM10- or ADAM17-dependent processing. Taken together, the present study provides new information about the molecular fingerprint of ADAM9 in cell-based assays by showing that it is not stimulated by strong activators of ectodomain shedding and by defining a characteristic inhibitor profile. The identification of novel non-hydroxamate inhibitors of ADAM9 could provide the basis for designing more selective compounds that block the contribution of ADAM9 to pathological neovascularization and cancer.

MicroRNA-27a contributes to the malignant behavior of gastric cancer cells by directly targeting PH domain and leucine-rich repeat protein phosphatase 2

Background

Accumulating evidence indicates that microRNA-27a (miR-27a) is involved in carcinogenesis and tumor progression. However, the exact function and molecular mechanism of miR-27a in gastric cancer remain unclear.

Methods

Quantitative real-time PCR (qRT-PCR) was used to quantify the expression of miR-27a and its target gene. The function of miR-27a in gastric cancer was investigated through in vitro and in vivo assays (MTT assay, colony formation assay, flow cytometry assay, wound healing assay, migration and invasion assay, immunohistochemistry (IHC), immunofluorescence (IF) and Western blot). A luciferase reporter assay was conducted to confirm the target gene of miR-27a.

Results

We found that miR-27a was commonly overexpressed in gastric cancer and high expression of miR-27a was associated with distant metastasis, lymph node metastasis, advanced T stage and advanced clinical stage. Functional assays demonstrated that overexpression of miR-27a in AGS cells accelerated cell proliferation, migration and invasion and suppressed apoptosis. Meanwhile, opposite results were observed in SGC-7901 cells when miR-27a was suppressed. Consistently, down-regulation of miR-27a inhibited the growth and metastasis of engrafted tumors in vivo. Furthermore, we found PH domain and leucine-rich repeat protein phosphatase 2 (PHLPP2) to be a new target of miR-27a, and downregulation of PHLPP2 could rescue the effect of anti-miR-27a in gastric cancer cells. In addition, miR-27a-mediated suppression of PHLPP2 led to stimulation of the AKT/GSK3β pathway.

Conclusions

Our data suggest that miR-27a functions as a crucial oncogenic miRNA in gastric cancer. It can promote proliferation and metastasis of tumor cells by suppressing PHLPP2 and activating the AKT/GSK3β pathway. Therefore, miR-27a is a potential novel therapeutic target in gastric cancer treatment.

Electronic supplementary material

The online version of this article (doi:10.1186/s13046-017-0516-2) contains supplementary material, which is available to authorized users.