ADAM12 induction by Twist1 promotes tumor invasion and metastasis via regulation of invadopodia and focal adhesions

Triptolide Reduces MDA-MB-231 Cell Metastasis by Attenuating Epithelial-Mesenchymal Transition through the ROCK/PTEN/Akt Axis

Triple-negative breast cancer (TNBC) is a highly heterogeneous and invasive subtype of breast cancer. The prognosis of TNBC is poor because of its high distant metastasis rate. Triptolide is a type of diterpene trioxide natural compound with potential anti-tumor activities. This study explored the metastatic inhibitory effect of triptolide on MDA-MB-231 cells and its underlying mechanism. Triptolide suppressed cell proliferation and induced cell apoptosis in a time- and dose-dependent manner. Low doses of triptolide (0-8 nM) reduced the migration and invasion capabilities of MDA-MB-231 cells. Triptolide decreased ROCK1, p-Akt, N-cadherin, vimentin and MMP-9 expressions, but increased PTEN and E-cadherin expressions on protein and mRNA levels. Furthermore, the down-regulation of ROCK1 expression in MDA-MB-231 cells after being treated by triptolide could be rescued by ROCK1 specific inhibitor Y27632. Molecular docking showed that triptolide and Y27632 shared the same active center of ROCK1 protein. This article's findings taken together showed that ROCK1 is the primary target of triptolide, which can cause cell apoptosis and inhibit the epithelial-mesenchymal transition of MDA-MB-231 cells.

A disintegrin and metalloprotease 12 contributes to colorectal cancer metastasis by regulating epithelial‑mesenchymal transition

A disintegrin and metalloprotease 12 (ADAM12) and epithelial‑mesenchymal transition (EMT) are linked in the metastasis of various types of cancer. The present study aimed to assess the ability of ADAM12 to induce EMT and its potential as a therapeutic target for colorectal cancer (CRC). ADAM12 expression in CRC cell lines, CRC tissues and a mouse model of peritoneal metastasis was assessed. The effect of ADAM12 on CRC EMT and metastasis was investigated using ADAM12‑pcDNA6‑myc and ADAM12‑pGFP‑C‑shLenti constructs. ADAM12 overexpression enhanced the proliferation, migration, invasion and EMT of CRC cells. The phosphorylation levels of factors associated with the PI3K/Akt pathway were also increased by ADAM12 overexpression. The knockdown of ADAM12 reversed these effects. ADAM12 expression and the loss of E‑cadherin expression were significantly associated with poorer survival compared with other expression statuses of both proteins. In a mouse model of peritoneal metastasis, overexpression of ADAM12 induced increased tumor weight and peritoneal carcinomatosis index compared with that in the negative control group. Conversely, knockdown of ADAM12 reversed these effects. Furthermore, E‑cadherin expression was significantly decreased by overexpression of ADAM12 compared with in the negative control group. By contrast, E‑cadherin expression was increased by knockdown of ADAM12 compared with in the negative control group. ADAM12 overexpression contributed to CRC metastasis by regulating EMT. In addition, in the mouse model of peritoneal metastasis, ADAM12 knockdown exhibited strong anti‑metastatic action. Consequently, ADAM12 may be considered a therapeutic target for CRC metastasis.

Weighted gene co-expression network reveals driver genes contributing to phenotypes of anaplastic thyroid carcinoma and immune checkpoint identification for therapeutic targets

Background

Anaplastic thyroid carcinoma (ATC) is a rare but extremely malignant tumor, with a rapid growth rate and early metastasis thus leading to poor survival of patients. The molecular mechanisms underlying these aggressive traits of ATC remain unknown, which impedes the substantial progress in treatment to prolong ATC patient survival.

Methods

We applied weighted gene co-expression network analysis (WGCNA) to identify ATC-specific modules. The Metascape web and R package clusterProfiler were employed to perform enrichment analysis. Combined with differentially expressed gene analysis, we screened out the most potential driver genes and validated them using receiver operator characteristic (ROC) analysis, quantitative reverse transcription polymerase chain reaction (qRT-PCR), western blotting, immunohistochemistry (IHC), and triple immunofluorescence staining.

Results

A gene expression matrix covering 75 normal samples, 83 papillary thyroid carcinoma (PTC), 26 follicular thyroid carcinoma (FTC), 19 poor-differentiated thyroid carcinoma (PDTC), and 41 ATC tissue samples were integrated, based on which we detected three most potential ATC-specific modules and found that hub genes of these modules were enriched in distinct biological signals. Hub genes in the turquoise module were mainly enriched in mitotic cell cycle, tube morphogenesis, and cell differentiation, hub genes in the magenta module were mainly clustered in the extracellular matrix organization, positive regulation of cell motility, and regulation of Wnt signaling pathway, while hub genes in the blue module primarily participated in the inflammatory response, innate immune response, and adaptive immune response. We showed that 9 top genes, 8 transcription factors (TFs), and 4 immune checkpoint genes (ICGs) were differentially expressed in ATC compared to other thyroid samples and had high diagnostic values for ATC, among which, 9 novel ATC-specific genes (ADAM12, RNASE2, CASP5, KIAA1524, E2F7, MYBL1, SRPX2, HAVCR2, and TDO2) were validated with our clinical samples. Furthermore, we illustrated that ADAM12, RNASE2, and HAVCR2 were predominantly present in the cytoplasm.

Conclusion

Our study identified a set of novel ATC-specific genes that were mainly related to cell proliferation, invasion, metastasis, and immunosuppression, which might throw light on molecular mechanisms underlying aggressive phenotypes of ATC and provide promisingly diagnostic biomarkers and therapeutic targets.

Proteolytic and mechanical remodeling of the extracellular matrix by invadopodia in cancer

Cancer invasion and metastasis require remodeling of the adjacent extracellular matrix (ECM). In this mini review, we will cover the mechanisms of proteolytic degradation and the mechanical remodeling of the ECM by cancer cells, with a focus on invadopodia. Invadopodia are membrane protrusions unique to cancer cells, characterized by an actin core and by the focal degradation of ECM via matrix metalloproteases (MMPs). While ECM can also be remodeled, at lower levels, by focal adhesions, or internal collagen digestion, invadopodia are now recognized as the major mechanism for MMP-dependent pericellular ECM degradation by cancer cells. Recent evidence suggests that the completion of epithelial-mesenchymal transition may be dispensable for invadopodia and metastasis, and that invadopodia are required not only for mesenchymal, single cell invasion, but also for collective invasion. During collective invasion, invadopodia was then shown to be located in leader cells, allowing follower cells to move via cooperation. Collectively, this suggests that invadopodia function may be a requirement not only for later steps of metastasis, but also for early invasion of epithelial cells into the stromal tissue. Over the last decade, invadopodia studies have transitioned into in 3D andin vivosettings, leading to the confirmation of their essential role in metastasis in preclinical animal models. In summary, invadopodia may hold a great potential for individual risk assessment as a prognostic marker for metastasis, as well as a therapeutic target.

Identification of the circRNA-miRNA-mRNA Regulatory Network in Pterygium-Associated Conjunctival Epithelium

To investigate the regulatory mechanism of pterygium formation, we detected differentially expressed messenger RNAs (DE-mRNAs) and differentially expressed circular RNAs (DE-circRNAs) in pterygium-associated conjunctival epithelium (PCE) and normal conjunctival epithelium (NCE). Genome-wide mRNA and circRNA expression profiles of PCE and NCE were determined using high-throughput sequencing. Bioinformatics analyses, including Gene Ontology (GO) analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, gene set enrichment analysis (GSEA), and protein-protein interaction (PPI) analysis, were conducted. The microRNAs (miRNAs) interacting with the hub DE-mRNAs and DE-circRNAs were predicted and verified using real-time quantitative PCR (RT-qPCR). The data showed that there were 536 DE-mRNAs (280 upregulated and 256 downregulated mRNAs) and 78 DE-circRNAs (20 upregulated and 58 downregulated circRNAs) in PCE. KEGG enrichment analysis indicated that the DE-mRNAs were mainly involved in the following biological processes: IL-17 signalling pathway, viral protein interaction with cytokine and cytokine receptor, cytokine-cytokine receptor interaction, ECM-receptor interaction, and focal adhesion. The GSEA results revealed that the epithelial mesenchymal transition (EMT) process was significantly enriched in upregulated mRNAs. The pterygium-associated circRNA-miRNA-mRNA network was established based on the top 10 DE-circRNAs, 4 validated miRNAs (upregulated miR-376a-5p and miR-208a-5p,downregulated miR-203a-3p and miR-200b-3p), and 31 DE-mRNAs. We found that miR-200b-3p, as a regulator of FN1, SDC2, and MEX3D, could be regulated by 5 upregulated circRNAs. In addition, we screened out EMT-related DE-mRNAs, including 6 upregulated DE-mRNAs and 6 downregulated DE-mRNAs. The EMT-related circRNA-miRNA-mRNA network was established with the top 10 circRNAs, 8 validated miRNAs (upregulated miR-17-5p, miR-181a-5p, and miR-106a-5p, downregulated miR-124-3p, miR-9-5p, miR-130b-5p, miR-1-3p, and miR-26b-5P), and 12 EMT-related DE-mRNAs. We found that hsa_circ_0002406 might upregulate FN1 and ADAM12 by sponging miR-26b-5p and miR-1-3p, respectively, thus promoting EMT in pterygium. Briefly, the study provides a novel viewpoint on the molecular pathological mechanisms in pterygium formation. CircRNA-miRNA-mRNA regulatory networks participate in the pathogenesis of pterygium and might become promising targets for pterygium prevention and treatment.

Beyond Genetics: Metastasis as an Adaptive Response in Breast Cancer

Metastatic disease represents the primary cause of breast cancer (BC) mortality, yet it is still one of the most enigmatic processes in the biology of this tumor. Metastatic progression includes distinct phases: invasion, intravasation, hematogenous dissemination, extravasation and seeding at distant sites, micro-metastasis formation and metastatic outgrowth. Whole-genome sequencing analyses of primary BC and metastases revealed that BC metastatization is a non-genetically selected trait, rather the result of transcriptional and metabolic adaptation to the unfavorable microenvironmental conditions which cancer cells are exposed to (e.g., hypoxia, low nutrients, endoplasmic reticulum stress and chemotherapy administration). In this regard, the latest multi-omics analyses unveiled intra-tumor phenotypic heterogeneity, which determines the polyclonal nature of breast tumors and constitutes a challenge for clinicians, correlating with patient poor prognosis. The present work reviews BC classification and epidemiology, focusing on the impact of metastatic disease on patient prognosis and survival, while describing general principles and current in vitro/in vivo models of the BC metastatic cascade. The authors address here both genetic and phenotypic intrinsic heterogeneity of breast tumors, reporting the latest studies that support the role of the latter in metastatic spreading. Finally, the review illustrates the mechanisms underlying adaptive stress responses during BC metastatic progression.

Histone H3K9 methyltransferase SETDB1 augments invadopodia formation to promote tumor metastasis

Non-small cell lung cancer (NSCLC) is one of leading causes of cancer-related mortality worldwide, which harbors various accumulated genetic and epigenetic abnormalities. Histone methyltransferase SETDB1 is a pivotal epigenetic regulator whose focal amplification and upregulation are commonly detected in NSCLC. However, molecular mechanisms underlying the pro-oncogenic function of SETDB1 remain poorly characterized. Here, we demonstrate that SETDB1 augments the migration and invasion capabilities of NSCLC cells by reinforcing invadopodia formation and mediated ECM degradation. At the molecular level, SETDB1 suppresses the expression of FOXA2, a crucial tumor and metastasis suppressor via coordinated epigenetic mechanisms - SETDB1 not only catalyzes histone H3K9 methylation on FOXA2 genomic locus, but also recruits DNMT3A to regulate DNA methylation on CpG island. Consequently, depletion of Setdb1 in murine lung adenocarcinoma cells completely abolished their full and spontaneous metastatic capabilities in mouse xenograft models. These findings together establish the pro-metastasis activity of SETDB1 in NSCLC and elucidate the underlying cellular and molecular mechanisms.

Transcriptional Factor Repertoire of Breast Cancer in 3D Cell Culture Models

Simple Summary

Knowledge of the transcriptional regulation of breast cancer tumorigenesis is largely based on studies performed in two-dimensional (2D) monolayer culture models, which lack tissue architecture and therefore fail to represent tumor heterogeneity. However, three-dimensional (3D) cell culture models are better at mimicking in vivo tumor microenvironment, which is critical in regulating cellular behavior. Hence, 3D cell culture models hold great promise for translational breast cancer research.

Abstract

Intratumor heterogeneity of breast cancer is driven by extrinsic factors from the tumor microenvironment (TME) as well as tumor cell–intrinsic parameters including genetic, epigenetic, and transcriptomic traits. The extracellular matrix (ECM), a major structural component of the TME, impacts every stage of tumorigenesis by providing necessary biochemical and biomechanical cues that are major regulators of cell shape/architecture, stiffness, cell proliferation, survival, invasion, and migration. Moreover, ECM and tissue architecture have a profound impact on chromatin structure, thereby altering gene expression. Considering the significant contribution of ECM to cellular behavior, a large body of work underlined that traditional two-dimensional (2D) cultures depriving cell–cell and cell–ECM interactions as well as spatial cellular distribution and organization of solid tumors fail to recapitulate in vivo properties of tumor cells residing in the complex TME. Thus, three-dimensional (3D) culture models are increasingly employed in cancer research, as these culture systems better mimic the physiological microenvironment and shape the cellular responses according to the microenvironmental cues that will regulate critical cell functions such as cell shape/architecture, survival, proliferation, differentiation, and drug response as well as gene expression. Therefore, 3D cell culture models that better resemble the patient transcriptome are critical in defining physiologically relevant transcriptional changes. This review will present the transcriptional factor (TF) repertoire of breast cancer in 3D culture models in the context of mammary tissue architecture, epithelial-to-mesenchymal transition and metastasis, cell death mechanisms, cancer therapy resistance and differential drug response, and stemness and will discuss the impact of culture dimensionality on breast cancer research.

A Layered View on Focal Adhesions

Simple Summary

The cytoskeleton is a network of protein fibres within cells that provide structure and support intracellular transport. Focal adhesions are protein complexes associated with the outer cell membrane that are found at the ends of specialised actin fibres of this cytoskeleton. They mediate cell adhesion by connecting the cytoskeleton to the extracellular matrix, a protein and sugar network that surrounds cells in tissues. Focal adhesions also translate forces on actin fibres into forces contributing to cell migration. Cell adhesion and migration are crucial to diverse biological processes such as embryonic development, proper functioning of the immune system or the metastasis of cancer cells. Advances in fluorescence microscopy and data analysis methods provided a more detailed understanding of the dynamic ways in which proteins bind and dissociate from focal adhesions and how they are organised within these protein complexes. In this review, we provide an overview of the advances in the current scientific understanding of focal adhesions and summarize relevant imaging techniques. One of the key insights is that focal adhesion proteins are organised into three layers parallel to the cell membrane. We discuss the relevance of this layered nature for the functioning of focal adhesion.

Abstract

The cytoskeleton provides structure to cells and supports intracellular transport. Actin fibres are crucial to both functions. Focal Adhesions (FAs) are large macromolecular multiprotein assemblies at the ends of specialised actin fibres linking these to the extracellular matrix. FAs translate forces on actin fibres into forces contributing to cell migration. This review will discuss recent insights into FA protein dynamics and their organisation within FAs, made possible by advances in fluorescence imaging techniques and data analysis methods. Over the last decade, evidence has accumulated that FAs are composed of three layers parallel to the plasma membrane. We focus on some of the most frequently investigated proteins, two from each layer, paxillin and FAK (bottom, integrin signalling layer), vinculin and talin (middle, force transduction layer) and zyxin and VASP (top, actin regulatory layer). Finally, we discuss the potential impact of this layered nature on different aspects of FA behaviour.

Upregulation of ADAM12 Is Associated With a Poor Survival and Immune Cell Infiltration in Colon Adenocarcinoma

Background

A disintegrin and metalloprotease 12 (ADAM12) is a member of the multidomain protein family, but the mechanisms by which it affects prognosis and immune cell infiltration in patients with colon adenocarcinoma (COAD) remain unclear. Here, our study aimed to analyze the prognostic value of ADAM12 and investigate the correlation between ADAM12 expression and immune cell infiltration in patients with COAD.

Methods

Differential expression analyses were performed using the Oncomine and UALCAN databases, and prognostic analyses were conducted using PrognoScan, Gene Expression Profiling Interactive Analysis (GEPIA), and Kaplan–Meier Plotter. Then, the cBioPortal database was used to analyze alterations in the ADAM12 gene, and the STRING and Metascape websites were used to conduct Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses. Additionally, relationships between ADAM12 and the immune microenvironment were evaluated based on the TIMER, GEPIA, and TISIDB databases.

Results

ADAM12 was overexpressed in COAD tissues, and higher ADAM12 expression correlated with a worse prognosis for patients with COAD. The gene regulatory network suggested that ADAM12 was mainly enriched in extracellular matrix (ECM) organization, ECM proteoglycans, skeletal system development, and ossification, among other pathways. Moreover, ADAM12 expression significantly correlated with the abundance of CD4+ T cells, B cells, CD8+ T cells, neutrophils, macrophages, dendritic cells, and their markers, as well as lymphocytes, immunomodulators, and chemokines.

Conclusions

In colorectal tumors, ADAM12 may play vital roles in regulating the ECM and the recruitment of immune cells, and we suggest that ADAM12 will become a reliable biomarker for determining response to immunotherapy and the prognosis of patients with COAD.

Transcriptomic analysis of primate placentas and novel rhesus trophoblast cell lines informs investigations of human placentation

BACKGROUND

Proper placentation, including trophoblast differentiation and function, is essential for the health and well-being of both the mother and baby throughout pregnancy. Placental abnormalities that occur during the early stages of development are thought to contribute to preeclampsia and other placenta-related pregnancy complications. However, relatively little is known about these stages in humans due to obvious ethical and technical limitations. Rhesus macaques are considered an ideal surrogate for studying human placentation, but the unclear translatability of known human placental markers and lack of accessible rhesus trophoblast cell lines can impede the use of this animal model.

RESULTS

Here, we performed a cross-species transcriptomic comparison of human and rhesus placenta and determined that while the majority of human placental marker genes (HPGs) were similarly expressed, 952 differentially expressed genes (DEGs) were identified between the two species. Functional enrichment analysis of the 447 human-upregulated DEGs, including ADAM12, ERVW-1, KISS1, LGALS13, PAPPA2, PGF, and SIGLEC6, revealed over-representation of genes implicated in preeclampsia and other pregnancy disorders. Additionally, to enable in vitro functional studies of early placentation, we generated and thoroughly characterized two highly pure first trimester telomerase (TERT) immortalized rhesus trophoblast cell lines (iRP-D26 and iRP-D28A) that retained crucial features of isolated primary trophoblasts.

CONCLUSIONS

Overall, our findings help elucidate the molecular translatability between human and rhesus placenta and reveal notable expression differences in several HPGs and genes implicated in pregnancy complications that should be considered when using the rhesus animal model to study normal and pathological human placentation.

Hypoxia-inducible factor-dependent ADAM12 expression mediates breast cancer invasion and metastasis

Breast cancer patients with increased expression of hypoxia-inducible factors (HIFs) in primary tumor biopsies are at increased risk of metastasis, which is the major cause of breast cancer-related mortality. The mechanisms by which intratumoral hypoxia and HIFs regulate metastasis are not fully elucidated. In this paper, we report that exposure of human breast cancer cells to hypoxia activates epidermal growth factor receptor (EGFR) signaling that is mediated by the HIF-dependent expression of a disintegrin and metalloprotease 12 (ADAM12), which mediates increased ectodomain shedding of heparin-binding EGF-like growth factor, an EGFR ligand, leading to EGFR-dependent phosphorylation of focal adhesion kinase. Inhibition of ADAM12 expression or activity decreased hypoxia-induced breast cancer cell migration and invasion in vitro, and dramatically impaired lung metastasis after orthotopic implantation of MDA-MB-231 human breast cancer cells into the mammary fat pad of immunodeficient mice.

ADAM and ADAMTS Proteins, New Players in the Regulation of Hepatocellular Carcinoma Microenvironment

Simple Summary

Members of the adamalysin family are multi-domain proteins involved in many cancer-related functions. In this review, we will examine the literature on the involvement of adamalysins in hepatocellular carcinoma progression and their importance in the tumor microenvironment where they regulate the inflammatory response and the epithelial–mesenchymal transition. We complete this review with an analysis of adamalysin expression in a large cohort of patients with hepatocellular carcinoma from The Cancer Genome Atlas (TCGA) database. These original results give a new insight into the involvement of all adamalysins in the primary liver cancer.

Abstract

The tumor microenvironment plays a major role in tumor growth, invasion and resistance to chemotherapy, however understanding how all actors from microenvironment interact together remains a complex issue. The tumor microenvironment is classically represented as three closely connected components including the stromal cells such as immune cells, fibroblasts, adipocytes and endothelial cells, the extracellular matrix (ECM) and the cytokine/growth factors. Within this space, proteins of the adamalysin family (ADAM for a disintegrin and metalloproteinase; ADAMTS for ADAM with thrombospondin motifs; ADAMTSL for ADAMTS-like) play critical roles by modulating cell–cell and cell–ECM communication. During last decade, the implication of adamalysins in the development of hepatocellular carcinoma (HCC) has been supported by numerous studies however the functional characterization of most of them remain unsettled. In the present review we propose both an overview of the literature and a meta-analysis of adamalysins expression in HCC using data generated by The Cancer Genome Atlas (TCGA) Research Network.

Ratio of the interferon-γ signature to the immunosuppression signature predicts anti-PD-1 therapy response in melanoma

Immune checkpoint inhibitor (ICI) treatments produce clinical benefit in many patients. However, better pretreatment predictive biomarkers for ICI are still needed to help match individual patients to the treatment most likely to be of benefit. Existing gene expression profiling (GEP)-based biomarkers for ICI are primarily focused on measuring a T cell-inflamed tumor microenvironment that contributes positively to the response to ICI. Here, we identified an immunosuppression signature (IMS) through analyzing RNA sequencing data from a combined discovery cohort (n = 120) consisting of three publicly available melanoma datasets. Using the ratio of an established IFN-γ signature and IMS led to consistently better prediction of the ICI therapy outcome compared to a collection of nine published GEP signatures from the literature on a newly generated internal validation cohort (n = 55) and three published datasets of metastatic melanoma treated with anti-PD-1 (n = 54) and anti-CTLA-4 (n = 42), as well as in patients with gastric cancer treated with anti-PD-1 (n = 45), demonstrating the potential utility of IMS as a predictive biomarker that complements existing GEP signatures for immunotherapy.

NH2 -terminal fragment of ZF21 protein suppresses tumor invasion via inhibiting the interaction of ZF21 with FAK

Cellular migration, coupled with the degradation of the extracellular matrix (ECM), is a key step in tumor invasion and represents a promising therapeutic target in malignant tumors. Focal adhesions (FAs) and invadopodia, which are distinct actin-based cellular structures, play key roles in cellular migration and ECM degradation, respectively. The molecular machinery coordinating the dynamics between FAs and invadopodia is not fully understood, although several lines of evidence suggest that the disassembly of FAs is an important step in triggering the formation of invadopodia. In a previous study, we identified the ZF21 protein as a regulator of both FA turnover and invadopodia-dependent ECM degradation. ZF21 interacts with multiple factors for FA turnover, including focal adhesion kinase (FAK), microtubules, m-Calpain, and Src homology region 2-containing protein tyrosine phosphatase 2 (SHP-2). In particular, the dephosphorylation of FAK by ZF21 is a key event in tumor invasion. However, the precise role of ZF21 binding to FAK remains unclear. We established a method to disrupt the interaction between ZF21 and FAK using the FAK-binding NH₂ -terminal region of ZF21. Tumor cells expressing the ZF21-derived polypeptide had significantly decreased FA turnover, migration, invadopodia-dependent ECM degradation, and Matrigel invasion. Furthermore, the expression of the polypeptide inhibited an early step of experimental lung metastasis in mice. These findings indicate that the interaction of ZF21 with FAK is necessary for FA turnover as well as ECM degradation at the invadopodia. Thus, ZF21 is a potential regulator that coordinates the equilibrium between FA turnover and invadopodia activity by interacting with FAK.

Invadopodia: clearing the way for cancer cell invasion

The invasive nature of many cancer cells involves the formation of F-actin-based, lipid-raft-enriched membrane protrusions known as invadopodia or, more broadly, invadosomes. Invadopodia are specialized adhesive structures arising from ventral cell surface within cell-extracellular matrix (ECM) contacts and concentrate high proteolytic activities that allow cells to overcome the dense scaffold of local microenvironment, comprising a natural barrier to cell spreading. This degradative activity distinguishes invadopodia from other adhesive structures like focal adhesions, lamellipodia or filopodia, and is believed to drive cancer progression.

SP1-Mediated Upregulation of lncRNA LINC01614 Functions a ceRNA for miR-383 to Facilitate Glioma Progression Through Regulation of ADAM12

Background

Long non-coding RNAs (lncRNAs) play an imperative role in tumorigenesis, but few lncRNAs have been functionally characterized in glioma. The aim of the present study was to identify the role of long non-coding RNA LINC01614 (LINC01614) in glioma development and explore the underlying mechanisms of LINC01614/miR-383/ADAM12 axis.

Patients and Methods

LncRNA expression in glioma specimens was measured by lncRNA microarray and qRT-PCR. The prognostic value of LINC01614 expression was statistically analyzed in 112 glioma patients. Loss-of-function experiments were conducted to investigate the biological functions of LINC01614 in vitro. Luciferase analyses, ChIP assays, and RNA pull-down were performed to determine the underlying LINC01614 mechanisms.

Results

We identified a novel glioma-related lncRNA LINC01614 by analyzing TCGA datasets. The distinct upregulation of LINC01614 was observed in both glioma specimens and cell lines using RT-PCR. We also observed that LINC01614 upregulation was induced by nuclear transcription factor SP1. Clinical assays revealed that high levels of LINC01614 were associated with KPS, WHO grade and shorter overall survival of glioma patients. Multivariate analysis further confirmed that LINC01614 was an independent prognostic marker for glioma patients. Besides, functional assays displayed that silence of LINC01614 knockdown distinctly inhibited cell growth, migration and invasion and promoted cell apoptosis in glioma cells. LINC01614 expression was enriched in the cytoplasm of glioma cells. Mechanistic investigation revealed that LINC01614 functioned as a competing endogenous RNA to upregulate a disintegrin and metalloproteinase 12 (ADAM12) by sponging miR-383.

Conclusion

Overall, these findings showed that SP1-induced upregulation of LINC01614 promoted glioma malignant progression via modulating the miR-383/ADAM12 axis, which may provide a promising therapy for glioma.

A proximity-labeling proteomic approach to investigate invadopodia molecular landscape in breast cancer cells

Metastatic progression is the leading cause of mortality in breast cancer. Invasive tumor cells develop invadopodia to travel through basement membranes and the interstitial matrix. Substantial efforts have been made to characterize invadopodia molecular composition. However, their full molecular identity is still missing due to the difficulty in isolating them. To fill this gap, we developed a non-hypothesis driven proteomic approach based on the BioID proximity biotinylation technology, using the invadopodia-specific protein Tks5α fused to the promiscuous biotin ligase BirA* as bait. In invasive breast cancer cells, Tks5α fusion concentrated to invadopodia and selectively biotinylated invadopodia components, in contrast to a fusion which lacked the membrane-targeting PX domain (Tks5β). Biotinylated proteins were isolated by affinity capture and identified by mass spectrometry. We identified known invadopodia components, revealing the pertinence of our strategy. Furthermore, we observed that Tks5 newly identified close neighbors belonged to a biologically relevant network centered on actin cytoskeleton organization. Analysis of Tks5β interactome demonstrated that some partners bound Tks5 before its recruitment to invadopodia. Thus, the present strategy allowed us to identify novel Tks5 partners that were not identified by traditional approaches and could help get a more comprehensive picture of invadopodia molecular landscape.

Shedding New Light on Cancer Metabolism: A Metabolic Tightrope Between Life and Death

Since the earliest findings of Otto Warburg, who discovered the first metabolic differences between lactate production of cancer cells and non-malignant tissues in the 1920s, much time has passed. He explained the increased lactate levels with dysfunctional mitochondria and aerobic glycolysis despite adequate oxygenation. Meanwhile, we came to know that mitochondria remain instead functional in cancer cells; hence, metabolic drift, rather than being linked to dysfunctional mitochondria, was found to be an active act of direct response of cancer cells to cell proliferation and survival signals. This metabolic drift begins with the use of sugars and the full oxidative phosphorylation via the mitochondrial respiratory chain to form CO₂, and it then leads to the formation of lactic acid via partial oxidation. In addition to oncogene-driven metabolic reprogramming, the oncometabolites themselves alter cell signaling and are responsible for differentiation and metastasis of cancer cells. The aberrant metabolism is now considered a major characteristic of cancer within the past 15 years. However, the proliferating anabolic growth of a tumor and its spread to distal sites of the body is not explainable by altered glucose metabolism alone. Since a tumor consists of malignant cells and its tumor microenvironment, it was important for us to understand the bilateral interactions between the primary tumor and its microenvironment and the processes underlying its successful metastasis. We here describe the main metabolic pathways and their implications in tumor progression and metastasis. We also portray that metabolic flexibility determines the fate of the cancer cell and ultimately the patient. This flexibility must be taken into account when deciding on a therapy, since singular cancer therapies only shift the metabolism to a different alternative path and create resistance to the medication used. As with Otto Warburg in his days, we primarily focused on the metabolism of mitochondria when dealing with this scientific question.

microRNAs Orchestrate Pathophysiology of Breast Cancer Brain Metastasis: Advances in Therapy

Brain metastasis (BM) predominantly occurs in triple-negative (TN) and epidermal growth factor 2 (HER2)-positive breast cancer (BC) patients, and currently, there is an unmet need for the treatment of these patients. BM is a complex process that is regulated by the formation of a metastatic niche. A better understanding of the brain metastatic processes and the crosstalk between cancer cells and brain microenvironment is essential for designing a novel therapeutic approach. In this context, the aberrant expression of miRNA has been shown to be associated with BM. These non-coding RNAs/miRNAs regulate metastasis through modulating the formation of a metastatic niche and metabolic reprogramming via regulation of their target genes. However, the role of miRNA in breast cancer brain metastasis (BCBM) is poorly explored. Thus, identification and understanding of miRNAs in the pathobiology of BCBM may identify a novel candidate miRNA for the early diagnosis and prevention of this devastating process. In this review, we focus on understanding the role of candidate miRNAs in the regulation of BC brain metastatic processes as well as designing novel miRNA-based therapeutic strategies for BCBM.

Differential roles of protease isoforms in the tumor microenvironment

Alternative splicing of precursor mRNA is a key mediator of gene expression regulation leading to greater diversity of the proteome in complex organisms. Systematic sequencing of the human genome and transcriptome has led to our understanding of how alternative splicing of critical genes leads to multiple pathological conditions such as cancer. For many years, proteases were known only for their roles as proteolytic enzymes, acting to regulate/process proteins associated with diverse cellular functions. However, the differential expression and altered function of various protease isoforms, such as (i) anti-apoptotic activities, (ii) mediating intercellular adhesion, and (iii) modifying the extracellular matrix, are evidence of their specific contribution towards shaping the tumor microenvironment. Revealing the alternative splicing of protease genes and characterization of their protein products/isoforms with distinct and opposing functions creates a platform to understand how protease isoforms contribute to specific cancer hallmarks. Here, in this review, we address cancer-specific isoforms produced by the alternative splicing of proteases and their distinctive roles in the tumor microenvironment.

ADAM8 localizes to extravillous trophoblasts within the maternal-fetal interface and potentiates trophoblast cell line migration through a β1 integrin-mediated mechanism

STUDY QUESTION

Does A Disintegrin And Metalloproteinase 8 (ADAM8) control extravillous trophoblast (EVT) differentiation and migration in early human placental development?

SUMMARY ANSWER

ADAM8 mRNA preferentially localizes to invasive HLA-G-positive trophoblasts, associates with the acquirement of an EVT phenotype and promotes trophoblast migration through a mechanism requiring β1-integrin.

WHAT IS KNOWN ALREADY

Placental establishment in the first trimester of pregnancy requires the differentiation of progenitor trophoblasts into invasive EVTs that produce a diverse repertoire of proteases that facilitate matrix remodeling and activation of signaling pathways important in controlling cell migration. While multiple ADAM proteases, including ADAM8, are highly expressed by invasive trophoblasts, the role of ADAM8 in controlling EVT-related processes is unknown.

STUDY DESIGN, SIZE, DURATION

First trimester placental villi and decidua (6-12 weeks' gestation), primary trophoblasts and trophoblastic cell lines (JEG3, JAR, Bewo, HTR8/SVNeo) were used to examine ADAM8 expression, localization and function. All experiments were performed on at least three independent occasions (n = 3).

PARTICIPANTS/MATERIALS, SETTING, METHODS

Placental villi and primary trophoblasts derived from IRB approved first trimester placental (n = 24) and decidual (n = 4) were used to examine ADAM8 localization and expression by in situ RNAScope hybridization, flow cytometry, quantitative PCR and immunoblot analyses. Primary trophoblasts were differentiated into EVT-like cells by plating on fibronectin and were assessed by immunofluorescence microscopy and immunoblot analysis of keratin-7, vimentin, epidermal growth factor receptor (EGFR), HLA-G and ADAM8. ADAM8 function was examined in primary EVTs and trophoblastic cell lines utilizing siRNA-directed silencing and over-expression strategies. Trophoblast migration was assessed using Transwell chambers, cell-matrix binding was tested using fibronectin-adhesion assays, and ADAM8-β1-integrin interactions were determined by immunofluorescence microscopy, co-immunoprecipitation experiments and function-promoting/inhibiting antibodies.

MAIN RESULTS AND THE ROLE OF CHANCE

Within first trimester placental tissues, ADAM8 preferentially localized to HLA-G+ trophoblasts residing within anchoring columns and decidua. Functional experiments in primary trophoblasts and trophoblastic cell lines show that ADAM8 promotes trophoblast migration through a mechanism independent of intrinsic protease activity. We show that ADAM8 localizes to peri-nuclear and cell-membrane actin-rich structures during cell-matrix attachment and promotes trophoblast binding to fibronectin matrix. Moreover, ADAM8 potentiates β1-integrin activation and promotes cell migration through a mechanism dependent on β1-integrin function.

LIMITATIONS, REASONS FOR CAUTION

The primary limitation of this study was the use of in vitro experiments in examining ADAM8 function, as well as the implementation of immortalized trophoblastic cell lines. Histological localization of ADAM8 within placental and decidual tissue sections was limited to mRNA level analysis. Further, patient information corresponding to tissues obtained by elective terminations was not available.

WIDER IMPLICATIONS OF THE FINDINGS

The novel non-proteolytic pro-migratory role for ADAM8 in controlling trophoblast migration revealed by this study sheds insight into the importance of ADAM8 in EVT biology and placental development.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by grants from the Natural Sciences and Engineering Research Council of Canada (NSERC-Discovery Grant) and the Canadian Institutes of Health Research (CIHR-Open Operating Grant). There are no conflicts or competing interests.

TRIAL REGISTRATION NUMBER

NA.

Mechanisms of Metastasis and Cell Mobility - The Role of Metabolism

Tumour metastasis is responsible for more than 90% of tumour-associated mortality. About one third of breast cancer patients in the early stage develop metastases. The transformation in tumour development referred to as the "metastatic cascade" or "metastatic cycle" is a complex and multi-stage event. While it is generally recognised that epithelial-mesenchymal transformation (EMT) plays a crucial role in cancer progression and metastasis, the metabolic events in this process have received little attention to date. We would therefore like to provide a brief overview here of the influence of the metabolism on the progression and metastasis of tumours.

Roles of EphA1/A2 and ephrin-A1 in cancer

The biological functions of the Eph/ephrin system have been intensively investigated and well documented so far since its discovery in 1987. Although the Eph/ephrin system has been implicated in pathological settings such as Alzheimer's disease and cancer, the molecular mechanism of the Eph/ephrin system in those diseases is not well understood. Especially in cancer, recent studies have demonstrated that most of Eph and ephrin are up‐ or down‐regulated in various types of cancer, and have been implicated in tumor progression, tumor malignancy, and prognosis. However, they lack consistency and are in controversy. The localization patterns of EphA1 and EphA2 in mouse lungs are very similar, and both knockout mice showed similar phenotypes in the lungs. Ephrin‐A1 that is a membrane‐anchored ligand for EphAs was co‐localized with EphA1 and EphA2 in lung vascular endothelial cells. We recently uncovered the molecular mechanism of ephrin‐A1‐induced lung metastasis by understanding the physiological function of ephrin‐A1 in lungs. This review focuses on the function of EphA1, EphA2, and ephrin‐A1 in tumors and an establishment of pre‐metastatic microenvironment in the lungs.

Adam12 and lnc015192 act as ceRNAs in breast cancer by regulating miR-34a

Long non-coding RNAs (lncRNAs) are reported to play vital roles in the progress of multiple cancers. However, the functions of lncRNAs in breast cancer remain to be discovered. We performed microarrays to identify the differentially expressed mRNAs and lncRNAs in breast tissues with or without miR-34a knockout. To explore the functions of the differentially expressed mRNA and lncRNA in breast cancer, we conducted a series of experiments. We found that Adam12 and lnc015192 were significantly upregulated in miR-34a knockout breast tissues. Knockdown of Adam12 and lnc015192 inhibited breast cancer cell migration, invasion, and epithelial-mesenchymal transition (EMT). Further experiments revealed that lnc015192 regulated Adam12 expression by functioning as a competing endogenous RNA (ceRNA) for miR-34a. In summary, our study demonstrate that Adam12 and lnc015192 promote breast cancer metastasis partly by sponging miR-34a through the ceRNA mechanism.

Proteomic screening identifies the zonula occludens protein ZO-1 as a new partner for ADAM12 in invadopodia-like structures

The epithelial mesenchymal transition (EMT) is a key process for cancer cell invasion and migration. This complex program whereby epithelial tumor cells loose polarity and acquire mesenchymal phenotype is driven by the regulation of cell-cell adhesion and cell-substrate interactions. We recently described the association of ADAM12 with EMT and we now use immunoprecipitation and proteomic approaches to identify interacting partners for ADAM12 during EMT. We identify twenty proteins that are involved in molecular mechanisms associated with adhesion/invasion processes. Integrative network analyses point out the zonula occludens protein ZO-1, as a new potential partner for ADAM12. In silico screening demonstrates that ZO-1 and ADAM12 are coexpressed in breast cancer cell lines sharing EMT signature. We validate the interaction between ZO-1 and ADAM12 in invasive breast cancer cell lines and show that ZO-1 and ADAM12 co-localize in actin- and cortactin-rich structures. Silencing either ADAM12 or ZO-1 inhibits gelatin degradation demonstrating that both proteins are required for matrix degradation. We further show that matrix metalloprotease 14, known to mediate degradation of collagen in invadopodia-like structures interacts with ZO-1. Depletion of PKCε that regulates the recruitment of ADAM12 and ZO-1 to cell membranes induces a decrease in ADAM12 and ZO-1 at invadopodia-like structures and degradation activity. Together our data provide evidence for a new interaction between ADAM12, a mesenchymal marker induced during TGF-β-dependent EMT and ZO-1, a scaffolding protein expressed in tight junctions of epithelial cells, both proteins being redistributed at the invadopodia-like structures of mesenchymal invasive cells to promote PKCε-dependent matrix degradation.

An ADAM12 and FAK positive feedback loop amplifies the interaction signal of tumor cells with extracellular matrix to promote esophageal cancer metastasis

Esophageal squamous cell carcinomas (ESCCs) have a poor prognosis mostly due to early metastasis. To explore the early event of metastasis in ESCC, we established an in vitro selection model to mimic the interaction of tumor cells with extracellular matrix, through which a sub-line of ESCC cells with high invasive ability was generated. By comparing the gene expression profile of the highly invasive sub-line to that of the parental cells, ADAM12-L was identified as a candidate gene promoting ESCC cell invasion. Immunohistochemistry revealed that the ADAM12-L was overexpressed in human ESCC tissues, especially at cancer invasive edge, and ADAM12-L overexpression tightly correlated with increased metastasis and poor outcome of ESCC patients. Indeed, ADAM12-L knockdown reduced the invasion and metastasis of ESCC cells both in vitro and in vivo. Furthermore, we demonstrated that ADAM12-L participated in focal adhesion turnover and promoted the activation of focal adhesion kinase (FAK), which in turn increased ADAM12-L transcription through FAK/JNK/c-Jun axis. Therefore, a loop initiated from the cancer cell upon the engagement with extracellular matrix through FAK and c-Jun to enhance ADAM12-L expression is established, leading to the positive feedback of further FAK activation and prompting metastasis. Our study indicates that overexpression of ADAM12-L can serve as a precision marker to determine the activation of this loop. Targeting ADAM12-L to disrupt this positive feedback loop represents a promising strategy to treat the metastasis of esophageal cancers.

Tks adaptor proteins at a glance

Tyrosine kinase substrate (Tks) adaptor proteins are considered important regulators of various physiological and/or pathological processes, particularly cell migration and invasion, and cancer progression. These proteins contain PX and SH3 domains, and act as scaffolds, bringing membrane and cellular components in close proximity in structures known as invadopodia or podosomes. Tks proteins, analogous to the related proteins p47^phox, p40^phox and NoxO1, also facilitate local generation of reactive oxygen species (ROS), which aid in signaling at invadopodia and/or podosomes to promote their activity. As their name suggests, Tks adaptor proteins are substrates for tyrosine kinases, especially Src. In this Cell Science at a Glance article and accompanying poster, we discuss the known structural and functional aspects of Tks adaptor proteins. As the science of Tks proteins is evolving, this article will point out where we stand and what still needs to be explored. We also underscore pathological conditions involving these proteins, providing a basis for future research to develop therapies for treatment of these diseases.

Proteomic Dissection of Nanotopography-Sensitive Mechanotransductive Signaling Hubs that Foster Neuronal Differentiation in PC12 Cells

Neuronal cells are competent in precisely sensing nanotopographical features of their microenvironment. The perceived microenvironmental information will be “interpreted” by mechanotransductive processes and impacts on neuronal functioning and differentiation. Attempts to influence neuronal differentiation by engineering substrates that mimic appropriate extracellular matrix (ECM) topographies are hampered by the fact that profound details of mechanosensing/-transduction complexity remain elusive. Introducing omics methods into these biomaterial approaches has the potential to provide a deeper insight into the molecular processes and signaling cascades underlying mechanosensing/-transduction but their exigence in cellular material is often opposed by technical limitations of major substrate top-down fabrication methods. Supersonic cluster beam deposition (SCBD) allows instead the bottom-up fabrication of nanostructured substrates over large areas characterized by a quantitatively controllable ECM-like nanoroughness that has been recently shown to foster neuron differentiation and maturation. Exploiting this capacity of SCBD, we challenged mechanosensing/-transduction and differentiative behavior of neuron-like PC12 cells with diverse nanotopographies and/or changes of their biomechanical status, and analyzed their phosphoproteomic profiles in these settings. Versatile proteins that can be associated to significant processes along the mechanotransductive signal sequence, i.e., cell/cell interaction, glycocalyx and ECM, membrane/f-actin linkage and integrin activation, cell/substrate interaction, integrin adhesion complex, actomyosin organization/cellular mechanics, nuclear organization, and transcriptional regulation, were affected. The phosphoproteomic data suggested furthermore an involvement of ILK, mTOR, Wnt, and calcium signaling in these nanotopography- and/or cell mechanics-related processes. Altogether, potential nanotopography-sensitive mechanotransductive signaling hubs participating in neuronal differentiation were dissected.

ADAM12 induces EMT and promotes cell migration, invasion and proliferation in pituitary adenomas via EGFR/ERK signaling pathway

Pituitary adenomas are the second most common primary brain tumor with invasive properties. We have previously identified that ADAM12 (a disintegrin and metalloprotease 12) overexpression is associated with the tumor invasion of pituitary adenomas, however, the underlying mechanism remains unknown. This study aims to elucidate the mechanistic role of ADAM12 in regulating the tumor invasion of pituitary adenomas. In this study, we first showed that ADAM12 expression was concomitant with epithelial to mesenchymal transition (EMT) process in clinical specimens of human pituitary adenomas. Further functional studies showed that ADAM12 silencing in pituitary adenoma cells significantly inhibited the EMT process and suppressed cell migration, invasion and proliferation without influencing cell apoptosis. Mechanistically, ADAM12 silencing significantly reduced ectodomain shedding of epidermal growth factor receptor (EGFR) ligands and attenuated the EGFR/ERK signaling pathway. Blocking of EGFR signaling resulted in EMT suppression similar to silencing of ADAM12 and reduced cell migration, invasion and proliferation, while EGFR activation abolished the suppression on EMT, proliferation, migration and invasion induced by ADAM12 silencing. Moreover, ADAM12 silencing significantly impaired tumorigenesis and EMT of pituitary adenoma cells in vivo. Taken together, our study provide crucial evidence that ADAM12 induces EMT and promotes cell migration, invasion and proliferation in pituitary adenomas via EGFR/ERK signaling pathway. These finds strongly suggest that ADAM12 might serve as a novel valuable therapeutic target for pituitary adenomas.