Cadherin-11 increases migration and invasion of prostate cancer cells and enhances their interaction with osteoblasts

Dickkopf-1 (DKK1) drives growth and metastases in castration-resistant prostate cancer

Metastatic castration-resistant prostate cancer (mCRPC) is associated with a poor prognosis and remains an incurable fatal disease. Therefore, the identification of molecular markers involved in cancer progression is urgently needed to develop more-effective therapies. The present study investigated the role of the Wnt signaling modulator Dickkopf-1 (DKK1) in the growth and metastatic progression of mCRPC. DKK1 silencing through siRNA and deletion via CRISPR/Cas9 editing were performed in two different metastatic castration-resistant prostate cancer cell lines (PC3 and DU145). A xenograft tumor model was used to assess tumor growth and metastases. In in vitro experiments, both DKK1 silencing and deletion reduced cell growth and migration of both cell lines. DKK1 knockout clones (DKK1-KO) exhibited cell cycle arrest, tubulin reorganization, and modulation of tumor metastasis-associated genes. Furthermore, in DKK1-KO cells, E-cadherin re-expression and its membrane co-localization with β-catenin were observed, contributing to reduced migration; Cadherin-11, known to increase during epithelial-mesenchymal transition, was down-regulated in DKK1-KO cells. In the xenograft mouse model, DKK1 deletion not only reduced tumor growth but also inhibited the formation of lung metastases. In conclusion, our findings support the key role of DKK1 in the growth and metastatic dissemination of mCRPC, both in vitro and in vivo.

Distinct mesenchymal cell states mediate prostate cancer progression

In the complex tumor microenvironment (TME), mesenchymal cells are key players, yet their specific roles in prostate cancer (PCa) progression remain to be fully deciphered. This study employs single-cell RNA sequencing to delineate molecular changes in tumor stroma that influence PCa progression and metastasis. Analyzing mesenchymal cells from four genetically engineered mouse models (GEMMs) and correlating these findings with human tumors, we identify eight stromal cell populations with distinct transcriptional identities consistent across both species. Notably, stromal signatures in advanced mouse disease reflect those in human bone metastases, highlighting periostin's role in invasion and differentiation. From these insights, we derive a gene signature that predicts metastatic progression in localized disease beyond traditional Gleason scores. Our results illuminate the critical influence of stromal dynamics on PCa progression, suggesting new prognostic tools and therapeutic targets.

sBioSITe enables sensitive identification of the cell surface proteome through direct enrichment of biotinylated peptides

BACKGROUND

Cell surface proteins perform critical functions related to immune response, signal transduction, cell-cell interactions, and cell migration. Expression of specific cell surface proteins can determine cell-type identity, and can be altered in diseases including infections, cancer and genetic disorders. Identification of the cell surface proteome remains a challenge despite several enrichment methods exploiting their biochemical and biophysical properties.

METHODS

Here, we report a novel method for enrichment of proteins localized to cell surface. We developed this new approach designated surface Biotinylation Site Identification Technology (sBioSITe) by adapting our previously published method for direct identification of biotinylated peptides. In this strategy, the primary amine groups of lysines on proteins on the surface of live cells are first labeled with biotin, and subsequently, biotinylated peptides are enriched by anti-biotin antibodies and analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS).

RESULTS

By direct detection of biotinylated lysines from PC-3, a prostate cancer cell line, using sBioSITe, we identified 5851 peptides biotinylated on the cell surface that were derived from 1409 proteins. Of these proteins, 533 were previously shown or predicted to be localized to the cell surface or secreted extracellularly. Several of the identified cell surface markers have known associations with prostate cancer and metastasis including CD59, 4F2 cell-surface antigen heavy chain (SLC3A2) and adhesion G protein-coupled receptor E5 (CD97). Importantly, we identified several biotinylated peptides derived from plectin and nucleolin, both of which are not annotated in surface proteome databases but have been shown to have aberrant surface localization in certain cancers highlighting the utility of this method.

CONCLUSIONS

Detection of biotinylation sites on cell surface proteins using sBioSITe provides a reliable method for identifying cell surface proteins. This strategy complements existing methods for detection of cell surface expressed proteins especially in discovery-based proteomics approaches.

Cdh11: Roles in different diseases and potential value in disease diagnosis and treatment

Cadherin is a homophilic, Ca2+-dependent cell adhesion glycoprotein that mediates cell-cell adhesion. Among them, Cadherin-11 (CDH11), as a classical cadherin, participates in and influences many crucial aspects of human growth and development. Furthermore, The involvement of CDH11 has been identified in an increasing number of diseases, primarily including various tumorous diseases, fibrotic diseases, autoimmune diseases, neurodevelopmental disorders, and more. In various tumorous diseases, CDH11 acts not only as a tumor suppressor but can also promote migration and invasion of certain tumors through various mechanisms. Likewise, in non-tumorous diseases, CDH11 remains a pivotal factor in disease progression. In this context, we summarize the specific functionalities and mechanisms of CDH11 in various diseases, aiming to gain a more comprehensive understanding of the potential value of CDH11 in disease diagnosis and treatment. This endeavor seeks to provide more effective diagnostic and therapeutic strategies for clinical management across diverse diseases.

Cadherin-11 increases tumor cell proliferation and metastatic potential via Wnt pathway activation

During epithelial-mesenchymal transition (EMT) in cancer progression, tumor cells switch cadherin profile from E-cadherin to cadherin-11 (CDH11), which is accompanied by increased invasiveness and metastatic activity. However, the mechanism through which CDH11 may affect tumor growth and metastasis remains elusive. Here, we report that CDH11 was highly expressed in multiple human tumors and was localized on the membrane, in the cytoplasm and, surprisingly, also in the nucleus. Interestingly, β-catenin remained bound to carboxy-terminal fragments (CTFs) of CDH11, the products of CDH11 cleavage, and co-localized with CTFs in the nucleus in the majority of breast cancer samples. Binding of β-catenin to CTFs preserved β-catenin activity, whereas inhibiting CDH11 cleavage led to β-catenin phosphorylation and diminished Wnt signaling, similar to CDH11 knockout. Our data elucidate a previously unknown role of CDH11, which serves to stabilize β-catenin in the cytoplasm and facilitates its translocation to the nucleus, resulting in activation of Wnt signaling, with subsequent increased proliferation, migration and invasion potential.

Expression signature and molecular basis of CDH11 in OSCC detected by a combination of multiple methods

Oral squamous cell carcinoma (OSCC) is one of the most common malignancy in the oral cancer threatening human health and the survival rate of OSCC has not been effectively improved in recent decades, so more effective biomarkers for the targeted therapy of OSCC are needed. Moreover, the role of CDH11 in OSCC has not been intensively investigated. We here show that the CDH11 protein and mRNA expression levels in the OSCC tissues were all significantly higher than in the non-cancerous tissues using RT-qPCR and western blot. This study also revealed that patients with higher CDH11 levels showed a higher incidence of perineural invasion and lymph node metastasis. By using data available from the Cancer Genome Atlas (TCGA), Gene Expression Omnibus (GEO), and ArrayExpress databases, overexpressed CDH11 in OSCC that associated with patients'history of alcohol, negative Human Papilloma Virus (HPV) status, perineural invasion, infiltration of multiple immune cells, and Single-cell functional states including quiescence and angiogenesis, possessed an excellent discriminatory capability in the OSCC patients. Moreover, the majority of the biological processes or pathways were significantly clustered by co-expressed genes, including extracellular matrix organization, the epithelial to mesenchymal transition, carbon metabolism, and the PI3K-Akt signaling pathway, and the upstream transcriptional regulation mechanism of CDH11 in OSCC was showed on a transcription factor/miRNA-mRNA network with the online tool NetworkAnalyst. Finally, frequent mutation of CDH11 was observed on a mouse OSCC model through whole-genome sequencing. CDH11 might serve as a valuable biomarker in OSCC, as it was identified to be overexpressed in OSCC and related to its clinical progression.

Distinct mesenchymal cell states mediate prostate cancer progression

Alterations in tumor stroma influence prostate cancer progression and metastatic potential. However, the molecular underpinnings of this stromal-epithelial crosstalk are largely unknown. Here, we compare mesenchymal cells from four genetically engineered mouse models (GEMMs) of prostate cancer representing different stages of the disease to their wild-type (WT) counterparts by single-cell RNA sequencing (scRNA-seq) and, ultimately, to human tumors with comparable genotypes. We identified 8 transcriptionally and functionally distinct stromal populations responsible for common and GEMM-specific transcriptional programs. We show that stromal responses are conserved in mouse models and human prostate cancers with the same genomic alterations. We noted striking similarities between the transcriptional profiles of the stroma of murine models of advanced disease and those of of human prostate cancer bone metastases. These profiles were then used to build a robust gene signature that can predict metastatic progression in prostate cancer patients with localized disease and is also associated with progression-free survival independent of Gleason score. Taken together, this offers new evidence that stromal microenvironment mediates prostate cancer progression, further identifying tissue-based biomarkers and potential therapeutic targets of aggressive and metastatic disease.

Aberrant Cadherin11 expression predicts distant metastasis of gastric cancer

The prognosis of gastric cancer (GC) is significantly affected by distant metastases and postoperative recurrences. Bone metastasis is one of the worst prognostic metastases in GC; however, its molecular mechanisms and predictive biomarkers remain elusive. In prostate and breast cancers, it has been reported that overexpression of Cadherin 11 (CDH11), a mesenchymal cell-cell contact factor, is known to be correlated with bone metastasis. Overexpression of CDH11 mRNA in bulk GC tissues has also been reported to be associated with a worse prognosis. However, a more precise evaluation of CDH11 expression in GC cells is necessary to establish a robust link between CDH11 and metastatic features of GC. We performed immunohistochemical analysis of CDH11 expression in 342 GC cases, of which specimens were obtained at the time of surgery, with a special focus on its aberrant membranous expression in GC cells. The correlations between aberrant CDH11 expression and distant metastases and the prognosis of GC cases were statistically investigated. Approximately half of the GC cases investigated showed aberrant expression of CDH11 in the GC cells of primary lesions. Aberrant CDH11 expression was statistically associated with bone metastasis of GCs. Moreover, metastases to the liver and distant lymph nodes were also statistically correlated with CDH11 expression. Aberrant CDH11 expression in GC cells in primary tumor lesions was shown to be a predictive biomarker of distant metastases in GC. GCs with CDH11 expression require preventive clinical attention for the detection of metastatic lesions.

Roads to Stat3 Paved with Cadherins

The engagement of cadherins, cell-to-cell adhesion proteins, triggers a dramatic increase in the levels and activity of the Rac/Cdc42 GTPases, through the inhibition of proteasomal degradation. This leads to an increase in transcription and secretion of IL6 family cytokines, activation of their common receptor, gp130, in an autocrine manner and phosphorylation of the signal transducer and activator of transcription-3 (Stat3) on tyrosine-705 by the Jak kinases. Stat3 subsequently dimerizes, migrates to the nucleus and activates the transcription of genes involved in cell division and survival. The Src oncogene also increases Rac levels, leading to secretion of IL6 family cytokines and gp130 activation, which triggers a Stat3-ptyr705 increase. Interestingly, at the same time, Src downregulates cadherins in a quantitative manner, while cadherins are required to preserve gp130 levels for IL6 family signalling. Therefore, a fine balance between Src527F/Rac/IL6 and Src527F/cadherin/gp130 levels is in existence, which is required for Stat3 activation. This further demonstrates the important role of cadherins in the activation of Stat3, through preservation of gp130 function. Conversely, the absence of cadherin engagement correlates with low Stat3 activity: In sparsely growing cells, both gp130 and Stat3-ptyr705 levels are very low, despite the fact that cSrc is active in the FAK (focal adhesion kinase)/cSrc complex, which further indicates that the engagement of cadherins is important for Stat3 activation, not just their presence. Furthermore, the caveolin-1 protein downregulates Stat3 through binding and sequestration of cadherins to the scaffolding domain of caveolin-1. We hypothesize that the cadherins/Rac/gp130 axis may be a conserved pathway to Stat3 activation in a number of systems. This fact could have significant implications in Stat3 biology, as well as in drug testing and development.

Identification of Novel Pyroptosis-Related Gene Signatures to Predict Prostate Cancer Recurrence

Prostate cancer (PCa) is a common malignant type of urogenital tract tumor with poor prognosis. Despite therapeutic advances, the recurrence and mortality rates of PCa have continued to increase with poor prognoses. Pyroptosis, also known as inflammatory cell necrosis, is a recently identified type of programmed cell death that can regulate the invasiveness, differentiation, proliferation, and metastasis of tumor cells; thus, it has a profound effect on the prognosis of patients with tumors. However, the relationship between pyroptosis and PCa remains unclear. We first identified 25 pyroptosis-related genes (PRGs) that were differentially expressed between PCa tissues and matched normal tissues in The Cancer Genome Atlas (TCGA) cohort. Based on the expression levels of 25 PRGs, PCa patients were clearly divided into two clusters and 17 PRGs were found to be significantly different between the two clusters, suggesting probable roles for these genes in the progression and recurrence of PCa. Therefore, the GSE40272 dataset with recurrence follow-up information was used to verify their value. Univariate analysis suggested that 5/17 genes were associated with recurrence, the number of genes did not decrease after least absolute shrinkage and selection operator (LASSO) regression analysis, and 5 PRGs constituted the risk score formula. Low-risk and high-risk subgroups identified using the recurrence model showed different disease-free survival (DFS) times (P<0.001) and the risk score of five PRGs was a factor of independence for recurrence in patients with PCa. In addition, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses suggested that these pathways, and comprising PRGs might be closely related to carcinogenesis and invasion of tumors, tumor microenvironment, and immune response. In conclusion, the expression signatures of PRGs play an important role in predicting PCa recurrence.

Prostate tumor-induced stromal reprogramming generates Tenascin C that promotes prostate cancer metastasis through YAP/TAZ inhibition

Metastatic prostate cancer (PCa) in bone induces bone-forming lesions that enhance PCa progression. How tumor-induced bone formation enhances PCa progression is not known. We have previously shown that PCa-induced bone originates from endothelial cells (ECs) that have undergone endothelial-to-osteoblast (EC-to-OSB) transition by tumor-secreted bone morphogenetic protein 4 (BMP4). Here, we show that EC-to-OSB transition leads to changes in the tumor microenvironment that increases the metastatic potential of PCa cells. We found that conditioned medium (CM) from EC-OSB hybrid cells increases the migration, invasion, and survival of PC3-mm2 and C4-2B4 PCa cells. Quantitative mass spectrometry (Isobaric Tags for Relative and Absolute Quantitation) identified Tenascin C (TNC) as one of the major proteins secreted from EC-OSB hybrid cells. TNC expression in tumor-induced OSBs was confirmed by immunohistochemistry of MDA PCa-118b xenograft and human bone metastasis specimens. Mechanistically, BMP4 increases TNC expression in EC-OSB cells through the Smad1-Notch/Hey1 pathway. How TNC promotes PCa metastasis was next interrogated by in vitro and in vivo studies. In vitro studies showed that a TNC-neutralizing antibody inhibits EC-OSB-CM-mediated PCa cell migration and survival. TNC knockdown decreased, while the addition of recombinant TNC or TNC overexpression increased migration and anchorage-independent growth of PC3 or C4-2b cells. When injected orthotopically, PC3-mm2-shTNC clones decreased metastasis to bone, while C4-2b-TNC-overexpressing cells increased metastasis to lymph nodes. TNC enhances PCa cell migration through α5β1 integrin-mediated YAP/TAZ inhibition. These studies elucidate that tumor-induced stromal reprogramming generates TNC that enhances PCa metastasis and suggest that TNC may be a target for PCa therapy.

All bone metastases are not created equal: Revisiting treatment resistance in renal cell carcinoma

Renal cell carcinoma (RCC) is the most common malignancy of the kidney, representing 80-90% of renal neoplasms, and is associated with a five-year overall survival rate of approximately 74%. The second most common site of metastasis is bone. As patients are living longer due to new RCC targeting agents and immunotherapy, RCC bone metastases (RCCBM) treatment failure is more prevalent. Bone metastasis formation in RCC is indicative of a more aggressive disease and worse prognosis. Osteolysis is a prominent feature and causes SRE, including pathologic fractures. Bone metastasis from other tumors such as lung, breast, and prostate cancer, are more effectively treated with bisphosphonates and denosumab, thereby decreasing the need for palliative surgical intervention. Resistance to these antiresportives in RCCBM reflects unique cellular and molecular mechanisms in the bone microenvironment that promote progression via inhibition of the anabolic reparative response. Identification of critical mechanisms underlying RCCBM induced anabolic impairment could provide needed insight into how to improve treatment outcomes for patients with RCCBM, with the goals of minimizing progression that necessitates palliative surgery and improving survival.

CDH11 Regulates Adhesion and Transcellular Migration of Tongue Squamous Cell Carcinoma

Purpose

CDH11, as a member of cadherins, mediates homotypic cell adhesion. Some studies have shown that CDH11 plays an important role in the development of tumors, especially in the processes of tumor invasion and metastasis. While features of CDH11 in tongue squamous cell carcinoma (TSCC) are still indeterminate, the purpose of the present study is to explore the role of CDH11 in TSCC.

Methods

The expression of cadherin gene in a TSCC cell line with high metastatic potential (LN4) and the parental CAL27 were examined both in the TCGA database and in collected clinical samples, further verified by quantitative real-time PCR. The effects of CDH11 on the proliferation, apoptosis, migration, invasion and adhesion were tested in appropriate ways after CDH11 was overexpressed in TSCC cells.

Results

Among the 22 cadherin genes, CDH11 was one of the most obviously inhibited genes in LN4 cells as compared with the parental cells. Overexpression of CDH11 did not show a significant effect on cell proliferation, apoptosis, stemness, migration and invasion ability of TSCC cells themselves, but it increased the adhesion of TSCC cells with human oral epithelial cells and decreased their ability to pass through human oral epithelial cells (HOECs) for migration.

Conclusion

The results indicated that CDH11 plays as a tumor suppressor in tongue squamous cell carcinoma by inhibiting the invasion and migration of tongue cancer cells. CDH11 may serve as an effective clinical target for new tongue cancer treatments.

Cadherin-11 Deficiency Attenuates Ang-II-Induced Atrial Fibrosis and Susceptibility to Atrial Fibrillation

Background

Atrial fibrosis serves as a disease initiating mechanism in the development of atrial fibrillation. Angiotensin II (Ang-II), a key mediator for atrial fibrosis, aberrantly activates atrial fibroblasts (AFs) into myofibroblasts, resulting in subsequent excessive synthesis and deposition of extracellular matrix (ECM). Cadherin-11 (CDH11) is essential in the development of non-cardiac fibrotic diseases. In this study, we investigated its role in the pathogenesis and underlying mechanism of atrial fibrillation.

Methods

We obtained left atrial tissues from either patients with atrial fibrillation or Ang-II-induced atrial fibrosis mice. We utilized a global CDH11 knockout mouse (CDH11^-/-) model to determine the effect of CDH11 on AF cell proliferation, migration, ECM synthesis/deposition. RNA-Seq of isolated AFs from CDH11^-/- or normal mice was performed and differential expressed genes were analyzed. The mouse susceptibility to atrial fibrillation was examined by cardiac electrophysiology.

Results

We found that cadherin-11 was significantly up-regulated in fibrotic atrial tissue from patients with atrial fibrillation and Ang-II-induced mice. Both normal and CDH11^-/- mice did not develop atrial fibrosis at resting state. However, after Ang-II infusion, unlike severe atrial fibrosis occurred in normal mice, CDH11^-/- mice displayed a reduced atrial fibrosis. Atrial fibroblasts with CDH11 deletion from CDH11^-/- mice showed reduction in Ang-II-induced cell proliferation, migration and ECM synthesis/deposition, indicating the involvement of CDH11 in atrial fibrosis. Consistently, RNA-Seq of CDH11-null AFs uncovered significant decrease in pro-fibrotic gene expression. In addition, we identified reduction of transcripts associated with Smad2/3, ERK1/2 and JNK pathways. Further, CDH11^-/- mice showed a significantly attenuated Ang-II-induced susceptibility to atrial fibrillation.

Conclusion

Our results indicate that CDH11 potentiates Ang-II-induced activation of AFs. The pathogenesis of atrial fibrosis is through CDH11 mediated stimulation of Smad2/3, ERK1/2 and JNK pathways. Thus, CDH11 might serve as a novel therapeutic target for ameliorating the development of atrial fibrillation.

Conservation of Epithelial-to-Mesenchymal Transition Process in Neural Crest Cells and Metastatic Cancer

Epithelial to mesenchymal transition (EMT) is a highly conserved cellular process in several species, from worms to humans. EMT plays a fundamental role in early embryogenesis, wound healing, and cancer metastasis. For neural crest cell (NCC) development, EMT typically results in forming a migratory and potent cell population that generates a wide variety of cell and tissue, including cartilage, bone, connective tissue, endocrine cells, neurons, and glia amongst many others. The degree of conservation between the signaling pathways that regulate EMT during development and metastatic cancer (MC) has not been fully established, despite ample studies. This systematic review and meta-analysis dissects the major signaling pathways involved in EMT of NCC development and MC to unravel the similarities and differences. While the FGF, TGFβ/BMP, SHH, and NOTCH pathways have been rigorously investigated in both systems, the EGF, IGF, HIPPO, Factor Receptor Superfamily, and their intracellular signaling cascades need to be the focus of future NCC studies. In general, meta-analyses of the associated signaling pathways show a significant number of overlapping genes (particularly ligands, transcription regulators, and targeted cadherins) involved in each signaling pathway of both systems without stratification by body segments and cancer type. Lack of stratification makes it difficult to meaningfully evaluate the intracellular downstream effectors of each signaling pathway. Finally, pediatric neuroblastoma and melanoma are NCC-derived malignancies, which emphasize the importance of uncovering the EMT events that convert NCC into treatment-resistant malignant cells.

Pathogenic variants in CDH11 impair cell adhesion and cause Teebi hypertelorism syndrome

Teebi hypertelorism syndrome (THS; OMIM 145420) is a rare craniofacial disorder characterized by hypertelorism, prominent forehead, short nose with broad or depressed nasal root. Some cases of THS have been attributed to SPECC1L variants. Homozygous variants in CDH11 truncating the transmembrane and intracellular domains have been implicated in Elsahy-Waters syndrome (EWS; OMIM 211380) with hypertelorism. We report THS due to CDH11 heterozygous missense variants on 19 subjects from 9 families. All affected residues in the extracellular region of Cadherin-11 (CHD11) are highly conserved across vertebrate species and classical cadherins. Six of the variants that cluster around the EC2-EC3 and EC3-EC4 linker regions are predicted to affect Ca²⁺ binding that is required for cadherin stability. Two of the additional variants [c.164G > C, p.(Trp55Ser) and c.418G > A, p.(Glu140Lys)] are also notable as they are predicted to directly affect trans-homodimer formation. Immunohistochemical study demonstrates that CDH11 is strongly expressed in human facial mesenchyme. Using multiple functional assays, we show that five variants from the EC1, EC2-EC3 linker, and EC3 regions significantly reduced the cell-substrate trans adhesion activity and one variant from EC3-EC4 linker results in changes in cell morphology, focal adhesion, and migration, suggesting dominant negative effect. Characteristic features in this cohort included depressed nasal root, cardiac and umbilical defects. These features distinguished this phenotype from that seen in SPECC1L-related hypertelorism syndrome and CDH11-related EWS. Our results demonstrate heterozygous variants in CDH11, which decrease cell-cell adhesion and increase cell migratory behavior, cause a form of THS, as termed CDH11-related THS.

Metastatic Spread in Prostate Cancer Patients Influencing Radiotherapy Response

Radiotherapy and surgery are curative treatment options for localized prostate cancer (PCa) with a 5-year survival rate of nearly 100%. Once PCa cells spread into distant organs, such as bone, the overall survival rate of patients drops dramatically. The metastatic cascade and organotropism of PCa cells are regulated by different cellular subtypes, organ microenvironment, and their interactions. This cross-talk leads to pre-metastatic niche formation that releases chemo-attractive factors enforcing the formation of distant metastasis. Biological characteristics of PCa metastasis impacting on metastatic sites, burden, and latency is of clinical relevance. Therefore, the implementation of modern hybrid imaging technologies into clinical routine increased the sensitivity to detect metastases at earlier stages. This enlarged the number of PCa patients diagnosed with a limited number of metastases, summarized as oligometastatic disease. These patients can be treated with androgen deprivation in combination with local-ablative radiotherapy or radiopharmaceuticals directed to metastatic sites. Unfortunately, the number of patients with disease recurrence is high due to the enormous heterogeneity within the oligometastatic patient population and the lack of available biomarkers with predictive potential for metastasis-directed radiotherapy. Another, so far unmet clinical need is the diagnosis of minimal residual disease before onset of clinical manifestation and/or early relapse after initial therapy. Here, monitoring of circulating and disseminating tumor cells in PCa patients during the course of radiotherapy may give us novel insight into how metastatic spread is influenced by radiotherapy and vice versa. In summary, this review critically compares current clinical concepts for metastatic PCa patients and discuss the implementation of recent preclinical findings improving our understanding of metastatic dissemination and radiotherapy resistance into standard of care.

Research progress in the role and mechanism of Cadherin-11 in different diseases

Cadherin is an important cell-cell adhesion molecule, which mediates intercellular adhesion through calcium dependent affinity interaction. Cadherin-11 (CDH11, OB-cadherin) is a member of cadherin family, and its gene is situated on chromosome 16q22.1. Increasing lines of researches have proved that CDH11 plays important roles in the occurrence and development of a lot of diseases, such as tumors, arthritis and so on. CDH11 often leads to promoter methylation inactivation, which can induce cancer cell apoptosis, suppress cell motility and invasion, and can inhibit cancer through Wnt/β-catenin, AKT/Rho A and NF-κB signaling pathways. This review focused on the current knowledge of CDH11, including its function and mechanism in different diseases. In this article, we aimed to have a more comprehensive and in-depth understanding of CDH11 and to provide new ideas for the treatment of some diseases.

Bone metastasis: mechanisms, therapies, and biomarkers

Skeletal metastases are frequent complications of many cancers, causing bone complications (fractures, bone pain, disability) that negatively affect the patient's quality of life. Here, we first discuss the burden of skeletal complications in cancer bone metastasis. We then describe the pathophysiology of bone metastasis. Bone metastasis is a multistage process: long before the development of clinically detectable metastases, circulating tumor cells settle and enter a dormant state in normal vascular and endosteal niches present in the bone marrow, which provide immediate attachment and shelter, and only become active years later as they proliferate and alter the functions of bone-resorbing (osteoclasts) and bone-forming (osteoblasts) cells, promoting skeletal destruction. The molecular mechanisms involved in mediating each of these steps are described, and we also explain how tumor cells interact with a myriad of interconnected cell populations in the bone marrow, including a rich vascular network, immune cells, adipocytes, and nerves. We discuss metabolic programs that tumor cells could engage with to specifically grow in bone. We also describe the progress and future directions of existing bone-targeted agents and report emerging therapies that have arisen from recent advances in our understanding of the pathophysiology of bone metastases. Finally, we discuss the value of bone turnover biomarkers in detection and monitoring of progression and therapeutic effects in patients with bone metastasis.

Clinical and prognostic association of oncogene cadherin 11 in gastric cancer

The abnormal expression of cadherin-11 (CDH11) affects the progression of several types of cancer. However, the expression pattern and prognostic value of CDH11 in gastric cancer (GC) have not been reported. In the present study, the expression of CDH11 in patients with GC and its effect on their survival were analyzed using public cancer databases. The expression of CDH11 in GC tissues was significantly higher compared with that in normal gastric tissues. The expression of CDH11 was higher in advanced GC compared with early GC, and increased CDH11 was associated with tumor progression and poor prognosis in patients with GC. The high level of methylation in the promoter of CDH11 in GC tissues was not sufficient to reverse the upregulation of CDH11 caused by transcriptional activation. Finally, the expression pattern and prognostic significance of CDH11 in GC were validated using data from patients with GC recruited for the present study. Collectively, the present results demonstrated that CDH11 was upregulated in GC tissues, and suggested that high CDH11 expression may be associated with progression and poor prognosis in GC.

Prostate-specific antigen modulates the osteogenic differentiation of MSCs via the cadherin 11-Akt axis

BACKGROUND

A high prevalence of osteoblastic bone metastases is characteristic of prostate cancer. Prostate-specific antigen (PSA) is a serine protease uniquely produced by prostate cancer cells and is an important serological marker for prostate cancer. However, whether PSA modulates the osteogenic process remains largely unknown. In this study, we explored the effect of PSA on modulating the osteoblastic differentiation of mesenchymal stem cells (MSCs). In this study, we used flow cytometry, CCK-8 assay, Alizarin red S (ARS) staining and quantification, alkaline phosphatase (ALP) activity and staining, Western blotting, and quantitative real-time PCR (qRT-PCR) to explore the effect of PSA on osteogenic differentiation of MSCs.

RESULTS

We first demonstrated that although PSA did not affect the proliferation, morphology, or phenotype of MSCs, it significantly promoted the osteogenic differentiation of MSCs in a concentration-dependent manner. Furthermore, we demonstrated that PSA promoted the osteogenic differentiation of MSCs by elevating the expression of Cadherin 11 in MSCs and, thus, activating the Akt signaling pathway.

CONCLUSIONS

In conclusion, we demonstrated that PSA could promote the osteogenesis of MSCs through Akt signaling pathway activation by elevating the expression of cadherin-11 in MSCs. These findings imply a possible role of PSA in osteoblastic bone metastases in prostate cancer.

The Roles of Bone Marrow-Resident Cells as a Microenvironment for Bone Metastasis

It has been appreciated that the cross talk between bone metastatic cancer cells and bone marrow microenvironment influence one another to worsen bone metastatic disease progression. Bone marrow contains various cell types, including (1) cells of mesenchymal origin (e.g., osteoblasts, osteocytes, and adipocytes), (2) cells of hematopoietic origin (e.g., osteoclast and immune cells), and (3) others (e.g., endothelial cells and nerves). The recent studies have enabled us to discover many important cancer-derived factors responsible for the development of bone metastasis. However, many critical questions regarding the roles of bone microenvironment in bone metastatic progression remain elusive. To answer these questions, a deeper understanding of the cross talk between bone metastatic cancer and bone marrow microenvironment is clearly warranted.

Osteoblast lineage-specific cell-surface antigen (A7) regulates osteoclast recruitment and calcification during bone remodeling

Bone remodeling is a continuous process characterized by highly coordinated cell-cell interactions in distinct multi-cellular units. Osteoclasts, which are specialized bone resorbing cells, play a central role in bone remodeling. Although the RANKL/RANK axis determines the gross number of osteoclasts present in bone tissue, detailed molecular events regulating bone remodeling related to osteoclast recruitment, initiation of bone remodeling, and coupling of bone resorption and bone formation are still ambiguous. We hypothesized that osteoblast-specific cell-surface molecules contribute to the molecular modulation of bone remodeling. Therefore, we searched for regulatory cell-surface molecules expressed on osteoblasts by use of B-cell hybridoma technology. We obtained a monoclonal antibody A7 (A7 MAb) highly specific to cells of osteoblast-lineage. Here we describe the expression pattern and possible role of A7 antigen specifically recognized by A7 MAb. In vitro, A7 antigen was expressed on cell-surface of osteoblasts and osteoblast-like bone marrow stromal cells. In vivo, A7 antigen was detected in a subset of bone surface osteoblasts and in osteocytes, with a typical cell membrane expression pattern. Tissue array analysis showed only a limited expression of A7 antigen in osteocytes close to the bone surface. Immunoblotting and immunoprecipitation analysis showed that A7 antigen is a lineage-specific cell-surface protein with an approximate molecular weight of 45 KDa. Cross-linking of cell-surface A7 antigen in cultures of osteoclastogenesis showed stimulation of osteoclast formation. Marked suppression of calcification in primary osteoblast cultures was observed when A7 antigen was cross-linked with anti-A7 antigen MAb, A7 MAb. These data suggest that A7 antigen regulates recruitment of osteoclasts and triggering of calcification. A7 antigen may be an important molecule involved in the precise regulation of bone remodeling.

Pharmacodynamic study of radium-223 in men with bone metastatic castration resistant prostate cancer

BACKGROUND

Radium-223 is a targeted alpha-particle therapy that improves survival in men with metastatic castration resistant prostate cancer (mCRPC), particularly in men with elevated serum levels of bone alkaline phosphatase (B-ALP). We hypothesized that osteomimicry, a form of epithelial plasticity leading to an osteoblastic phenotype, may contribute to intralesional deposition of radium-223 and subsequent irradiation of the tumor microenvironment.

METHODS

We conducted a pharmacodynamic study (NCT02204943) of radium-223 in men with bone mCRPC. Prior to and three and six months after radium-223 treatment initiation, we collected CTCs and metastatic biopsies for phenotypic characterization and CTC genomic analysis. The primary objective was to describe the impact of radium-223 on the prevalence of CTC B-ALP over time. We measured radium-223 decay products in tumor and surrounding normal bone during treatment. We validated genomic findings in a separate independent study of men with bone metastatic mCRPC (n = 45) and publicly accessible data of metastatic CRPC tissues.

RESULTS

We enrolled 20 men with symptomatic bone predominant mCRPC and treated with radium-223. We observed greater radium-223 radioactivity levels in metastatic bone tumor containing biopsies compared with adjacent normal bone. We found evidence of persistent Cellsearch CTCs and B-ALP (+) CTCs in the majority of men over time during radium-223 therapy despite serum B-ALP normalization. We identified genomic gains in osteoblast mimicry genes including gains of ALPL, osteopontin, SPARC, OB-cadherin and loss of RUNX2, and validated genomic alterations or increased expression at the DNA and RNA level in an independent cohort of 45 men with bone-metastatic CRPC and in 150 metastatic biopsies from men with mCRPC.

CONCLUSIONS

Osteomimicry may contribute in part to the uptake of radium-223 within bone metastases and may thereby enhance the therapeutic benefit of this bone targeting radiotherapy.

GRP78 modulates cell adhesion markers in prostate Cancer and multiple myeloma cell lines

Background

Glucose regulated protein 78 (GRP78) is a resident chaperone of the endoplasmic reticulum and a master regulator of the unfolded protein response under physiological and pathological cell stress conditions. GRP78 is overexpressed in many cancers, regulating a variety of signaling pathways associated with tumor initiation, proliferation, adhesion and invasion which contributes to metastatic spread. GRP78 can also regulate cell survival and apoptotic pathways to alter responsiveness to anticancer drugs. Tumors that reside in or metastasize to the bone and bone marrow (BM) space can develop pro-survival signals through their direct adhesive interactions with stromal elements of this niche thereby resisting the cytotoxic effects of drug treatment. In this study, we report a direct correlation between GRP78 and the adhesion molecule N-cadherin (N-cad), known to play a critical role in the adhesive interactions of multiple myeloma and metastatic prostate cancer with the bone microenvironment.

Methods

N-cad expression levels (transcription and protein) were evaluated upon siRNA mediated silencing of GRP78 in the MM.1S multiple myeloma and the PC3 metastatic prostate cancer cell lines. Furthermore, we evaluated the effects of GRP78 knockdown (KD) on epithelial-mesenchymal (EMT) transition markers, morphological changes and adhesion of PC3 cells.

Results

GRP78 KD led to concomitant downregulation of N-cad in both tumors types. In PC3 cells, GRP78 KD significantly decreased E-cadherin (E-cad) expression likely associated with the induction in TGF-β1 expression. Furthermore, GRP78 KD also triggered drastic changes in PC3 cells morphology and decreased their adhesion to osteoblasts (OSB) dependent, in part, to the reduced N-cad expression.

Conclusion

This work implicates GRP78 as a modulator of cell adhesion markers in MM and PCa. Our results may have clinical implications underscoring GRP78 as a potential therapeutic target to reduce the adhesive nature of metastatic tumors to the bone niche.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-5178-8) contains supplementary material, which is available to authorized users.

A microfluidic chip-based co-culture of fibroblast-like synoviocytes with osteoblasts and osteoclasts to test bone erosion and drug evaluation

Targeting fibroblast-like synoviocyte (FLS) migration and invasion-mediated bone erosion is a promising clinical strategy for the treatment of rheumatoid arthritis (RA). Drug sensitivity testing is fundamental to this scheme. We designed a microfluidic chip-based, cell co-cultured platform to mimic RA FLS-mediated bone erosion and perform drug-sensitive assay. Human synovium SW982 cells were cultured in the central channel and migrated to flow through matrigel-coated side channels towards cell culture chamber where RANKL-stimulated osteoclastic RAW264.7 and osteogenic medium (OS)-stimulated bone marrow mesenchymal stem cells (BMSC) were cultured in the microfluidic chip device, mimicking FLS migration and invasion-mediated bone erosion in RA. These SW982 cells showed different migration potentials to osteoclasts and BMSC. The migration of SW982 cells with high expression of cadherin-11 was more potent when SW982 cells were connected with the co-culture of RAW264.7 and BMSC. Simultaneously, in the co-cultured chamber, tartrate-resistant acid phosphatase (TRAP) activity of RANKL-stimulated RAW264.7 cells was enhanced, but alkaline phosphatase (ALP) activity was decreased in comparison with mono-cultured chamber. Furthermore, it was confirmed that celastrol, a positive drug for the treatment of RA, inhibited SW982 cell migration as well as TRAP activity in the cell-cultured microfluidic chips. Thus, the migration and invasion to bone-related cells was reconstituted on the microfluidic model. It may provide an effective anti-RA drug screen model for targeting FLS migration-mediated bone erosion.

miRNA-30 Family Members Inhibit Breast Cancer Invasion, Osteomimicry, and Bone Destruction by Directly Targeting Multiple Bone Metastasis-Associated Genes

miRNAs are master regulators of gene expression that play key roles in cancer metastasis. During bone metastasis, metastatic tumor cells must rewire their biology and express genes that are normally expressed by bone cells (a process called osteomimicry), which endow tumor cells with full competence for outgrowth in the bone marrow. Here, we establish miR-30 family members miR-30a, miR-30b, miR-30c, miR-30d, and miR-30e as suppressors of breast cancer bone metastasis that regulate multiple pathways, including osteomimicry. Low expression of miR-30 in primary tumors from patients with breast cancer were associated with poor relapse-free survival. In addition, estrogen receptor (ER)-negative/progesterone receptor (PR)-negative breast cancer cells expressed lower miR-30 levels than their ER/PR-positive counterparts. Overexpression of miR-30 in ER/PR-negative breast cancer cells resulted in the reduction of bone metastasis burden in vivoIn vitro, miR-30 did not affect tumor cell proliferation, but did inhibit tumor cell invasion. Furthermore, overexpression of miR-30 restored bone homeostasis by reversing the effects of tumor cell-conditioned medium on osteoclastogenesis and osteoblastogenesis. A number of genes associated with osteoclastogenesis stimulation (IL8, IL11), osteoblastogenesis inhibition (DKK-1), tumor cell osteomimicry (RUNX2, CDH11), and invasiveness (CTGF, ITGA5, ITGB3) were identified as targets for repression by miR-30. Among these genes, silencing CDH11 or ITGA5 in ER-/PR-negative breast cancer cells recapitulated inhibitory effects of miR-30 on skeletal tumor burden in vivo Overall, our findings provide evidence that miR-30 family members employ multiple mechanisms to impede breast cancer bone metastasis and may represent attractive targets for therapeutic intervention.Significance: These findings suggest miR-30 family members may serve as an effective means to therapeutically attenuate metastasis in triple-negative breast cancer. Cancer Res; 78(18); 5259-73. ©2018 AACR.

Combined overexpression of cadherin 6, cadherin 11 and cluster of differentiation 44 is associated with lymph node metastasis and poor prognosis in oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is a highly invasive lesion that frequently metastasizes to the cervical lymph nodes and is associated with a poor prognosis. Several adhesion factors, including cadherin 6 (CDH6), cadherin 11 (CDH11) and cluster of differentiation 44 (CD44), have been reported to be involved in the invasion and metastasis of multiple types of cancer. Therefore, the aim of the present study was to determine the expression of CDH6, CDH11 and CD44 in tumor tissues from patients with OSCC, and whether this was associated with the metastasis and survival of OSCC. The mRNA expression of the human tumor metastasis-related cytokines was examined by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) in OSCC tumors with or without lymph node metastasis (n=10/group). The expression of CDH6, CDH11 and CD44 in 101 OSCC and 10 normal oral mucosa samples was examined by immunohistochemical staining. The association between overall and disease-specific survival times of patients with OSCC and the expression of these three proteins was evaluated using Kaplan-Meier curves and the log-rank test. RT-qPCR results indicated that the mRNA expression of CDH6, CDH11 and CD44 was increased in OSCC patients with lymph node metastasis (2.93-, 2.01- and 1.92-fold; P<0.05). Overexpression of CDH6, CDH11 and CD44 was observed in 31/35 (89%), 25/35 (71%) and 31/35 (89%) patients, respectively. The number of OSCC patients with lymph node metastasis exhibiting CDH6, CDH11 and CD44 overexpression was significantly higher than the number of patients without lymph node metastasis exhibiting overexpression of these proteins (P=0.017, P=0.038 and P=0.007, respectively). OSCC patients with high co-expression of CDH6, CDH11 and CD44 exhibited lower disease-specific survival times (P=0.047; χ²=3.933) when compared with OSCC patients with low co-expression of these adhesion factors. CDH6, CDH11 and CD44 serve important roles in OSCC metastasis and the combined use of these factors as biomarkers may improve the accuracy of the prediction of cancer metastases and prognosis.

Mesenchymal Stromal Cells: Emerging Roles in Bone Metastasis

Bone metastasis is the most advanced stage of many cancers and indicates a poor prognosis for patients due to resistance to anti-tumor therapies. The establishment of metastasis within the bone is a multistep process. To ensure survival within the bone marrow, tumor cells must initially colonize a niche in which they can enter dormancy. Subsequently, reactivation permits the proliferation and growth of the tumor cells, giving rise to a macro-metastasis displayed clinically as a bone metastatic lesion. Here, we review the evidences that suggest mesenchymal stromal cells play an important role in each of these steps throughout the development of bone metastasis. Similarities between the molecular mechanisms implicated in these processes and those involved in the homeostasis of the bone indicate that the metastatic cells may exploit the homeostatic processes to their own advantage. Identifying the molecular interactions between the mesenchymal stromal cells and tumor cells that promote tumor development may offer insight into potential therapeutic targets that could be utilized to treat bone metastasis.

Organelle-Derived Acetyl-CoA Promotes Prostate Cancer Cell Survival, Migration, and Metastasis via Activation of Calmodulin Kinase II

Although emerging evidence suggests a potential role of calcium/calmodulin-dependent kinase II (CaMKII) in prostate cancer, its role in prostate cancer tumorigenesis is largely unknown. Here, we examine whether the acetyl CoA-CaMKII pathway, first described in frog oocytes, promotes prostate cancer tumorigenesis. In human prostate cancer specimens, metastatic prostate cancer expressed higher levels of active CaMKII compared with localized prostate cancer. Correspondingly, basal CaMKII activity was significantly higher in the more tumorigenic PC3 and PC3-mm2 cells relative to the less tumorigenic LNCaP and C4-2B4 cells. Deletion of CaMKII by CRISPR/Cas9 in PC3-mm2 cells abrogated cell survival under low-serum conditions, anchorage-independent growth and cell migration; overexpression of constitutively active CaMKII in C4-2B4 cells promoted these phenotypes. In an animal model of prostate cancer metastasis, genetic ablation of CaMKII reduced PC3-mm2 cell metastasis from the prostate to the lymph nodes. Knockdown of the acetyl-CoA transporter carnitine acetyltransferase abolished CaMKII activation, providing evidence that acetyl-CoA generated from organelles is a major activator of CaMKII. Genetic deletion of the β-oxidation rate-limiting enzyme ACOX family proteins decreased CaMKII activation, whereas overexpression of ACOXI increased CaMKII activation. Overall, our studies identify active CaMKII as a novel connection between organelle β-oxidation and acetyl-CoA transport with cell survival, migration, and prostate cancer metastasis.Significance: This study identifies a cell metabolic pathway that promotes prostate cancer metastasis and suggests prostate cancer may be susceptible to β-oxidation inhibitors. Cancer Res; 78(10); 2490-502. ©2018 AACR.

The ectodomain of cadherin-11 binds to erbB2 and stimulates Akt phosphorylation to promote cranial neural crest cell migration

During development, a multi-potent group of cells known as the cranial neural crest (CNC) migrate to form craniofacial structures. Proper migration of these cells requires proteolysis of cell adhesion molecules, such as cadherins. In Xenopus laevis, preventing extracellular cleavage of cadherin-11 impairs CNC migration. However, overexpression of the soluble cleavage product (EC1-3) is capable of rescuing this phenotype. The mechanism by which EC1-3 promotes CNC migration has not been investigated until now. Here we show that EC1-3 stimulates phosphorylation of Akt, a target of PI3K, in X.laevis CNC. Through immunoprecipitation experiments, we determined that EC1-3 interacts with all ErbB receptors, PDGFRα, and FGFR1. Of these receptors, only ErbB2 was able to produce an increase in Akt phosphorylation upon treatment with a recombinant EC1-3. This increase was abrogated by mubritinib, an inhibitor of ErbB2. We were able to recapitulate this decrease in Akt phosphorylation in vivo by knocking down ErbB2 in CNC cells. Knockdown of the receptor also significantly reduced CNC migration in vivo. We confirmed the importance of ErbB2 and ErbB receptor signaling in CNC migration using mubritinib and canertinib, respectively. Mubritinib and the PI3K inhibitor LY294002 significantly decreased cell migration while canertinib nearly prevented it altogether. These data show that ErbB2 and Akt are important for CNC migration and implicate other ErbB receptors and Akt-independent signaling pathways. Our findings provide the first example of a functional interaction between the extracellular domain of a type II classical cadherin and growth factor receptors.

The role of cadherin-11 in microcystin-LR-induced migration and invasion in colorectal carcinoma cells

The present study aimed to explore whether microcystin-LR (MC-LR; a well-known cyanobacterial toxin produced in eutrophic lakes or reservoirs) induced tumor progression by activating cadherin-11(CDH11). A previous tumor metastasis PCR array demonstrated that MC-LR exposure resulted in a significant increase in the expression of CDH11. In the present study, to confirm the effect of the MC-LR treatment on CDH11 expression, HT-29 cell migration and invasion following MC-LR treatment were tested by Transwell assays, and protein levels of CDH11 were tested by immunofluorescence and western blot analysis. The results demonstrated that MC-LR activated CDH11 expression in addition to cell migration and invasion in HT-29 cells. To further investigate the association between MC-LR-induced CDH11 upregulation, and higher motility and invasiveness in HT-29 cells, knockdown of CDH11 using small interfering RNA (siRNA) in HT-29 cells was performed. Subsequent Transwell assays confirmed that MC-LR-induced enhancement of migration and invasion was significantly decreased following CDH11 knockdown by CDH11-siRNA in HT-29 cells. The results from the present study indicate that MC-LR may act as a CDH11 activator to promote HT-29 cell migration and invasion.

Interleukin enhancer-binding factor 3 and HOXC8 co-activate cadherin 11 transcription to promote breast cancer cells proliferation and migration

Cadherin 11 (CDH11) expression is detected only in invasive breast cancer cells and aggressive breast cancer specimens. However, little is known about the molecular mechanisms of CDH11 transcriptional regulation. Here, we report that interleukin enhancer binding factor 3 (ILF3) interacts with Homeobox C8 (HOXC8) to activate CDH11 transcription in breast cancer cells. Using co-immunoprecipitation and mass spectrometry analyses, ILF3 is shown to interact with HOXC8 in breast cancer cells. We demonstrate that ILF3 binds to the CDH11 promoter on nucleotides –2982 ~ –2978 and –2602 ~ 2598 and interacts with HOXC8 to co-activate CDH11 transcription. We further show that ILF3 promotes proliferation and migration, at least partially, by facilitating CDH11 expression in breast cancer cells. Moreover, immunohistochemistry (IHC) shows that expression of CDH11, ILF3 and HOXC8 are all upregulated in breast cancer specimens compared to normal breast tissues. Importantly, the expression levels of CDH11, ILF3 and HOXC8 are elevated in the advanced stages of breast cancer, and high expression of CDH11, ILF3 and HOXC8 is associated with poor distant metastasis-free survival (DMFS) for breast cancer patients.

Endothelial-to-Osteoblast Conversion Generates Osteoblastic Metastasis of Prostate Cancer

Prostate cancer (PCa) bone metastasis is frequently associated with bone-forming lesions, but the source of the osteoblastic lesions remains unclear. We show that the tumor-induced bone derives partly from tumor-associated endothelial cells that have undergone endothelial-to-osteoblast (EC-to-OSB) conversion. The tumor-associated osteoblasts in PCa bone metastasis specimens and patient-derived xenografts (PDXs) were found to co-express endothelial marker Tie-2. BMP4, identified in PDX-conditioned medium, promoted EC-to-OSB conversion of 2H11 endothelial cells. BMP4 overexpression in non-osteogenic C4-2b PCa cells led to ectopic bone formation under subcutaneous implantation. Tumor-induced bone was reduced in trigenic mice (Tie2^cre/Osx^f/f/SCID) with endothelial-specific deletion of osteoblast cell-fate determinant OSX compared with bigenic mice (Osx^f/f/SCID). Thus, tumor-induced EC-to-OSB conversion is one mechanism that leads to osteoblastic bone metastasis of PCa.

Pathophysiology of bone metastases from solid malignancies

Bone metastases are common complications of many cancers. Among the mechanisms that set the scene for the development of bone metastases, several are shared by all forms of metastatic dissemination (pre-metastatic niche formation and chemotactic attraction of malignant cells, which invade the host tissue) and others are specific of bone tissue (homing of malignant cells to bone marrow niches and acquisition of an osteomimetic cell phenotype). After a latency period that can last several years, the malignant cells can proliferate into tumors that alter the normal bone remodeling process by inducing dysregulation of osteoblast and osteoclast function. These metastases may be lytic, characterized by major bone destruction; sclerotic, with excess bone formation; or mixed. Osteolysis occurs when the tumor cells stimulate osteoclast activity and inhibit osteoblast activity, whereas the opposite effects lead to bone sclerosis. Moreover, the mineralized bone matrix plays a major role in the formation of bone metastases, as its degradation releases growth factors and calcium that exert mitogenic effects on tumor cells. Thus, bone metastases are the site of a vicious circle in which mechanisms involved in bone resorption/formation promote tumor growth and vice versa.

Determinants of bone specific metastasis in prostate cancer

Prostate cancer is one of the most common type of cancer in Western countries. Although the majority of patients with PCa have a minimally aggressive disease, some of them will experience relapse and formation of metastasis. Bone metastasis are a major cause of quality of life impairment and death among patients with metastatic prostate cancer. Different "bone targeted therapies" and several follow-up strategies were developed in order to optimize bone metastasis prevention and treatment. Nevertheless there is still a great clinical need of identifying patients more likely to benefit from those interventions as not all patients will develop metastatic disease and not all patients with metastatic disease will develop bone metastasis. Here we review markers predictive of bone metastasis occurrence that have been tested in clinical settings, particularly focusing on the ability of such markers to predict bone metastasis over visceral metastasis occurrence.

T-cadherin in prostate cancer: relationship with cancer progression, differentiation and drug resistance

Prostate cancer represents the second leading cause of cancer-related death in men. T-cadherin (CDH13) is an atypical GPI-anchored member of the cadherin family of adhesion molecules. Its gene was reported to be downregulated in a small series of prostate tumours. T-cadherin protein expression/localisation in prostate tissue has never been investigated. The purpose of our study was to analyse CDH13 gene and protein levels in large sets of healthy and cancer prostate tissue specimens and evaluate CDH13 effects on the sensitivity of prostate cancer cells to chemotherapy. Analysis of CDH13 gene expression in the TCGA RNAseq dataset for prostate adenocarcinoma (N = 550) and in tissue samples (N = 101) by qPCR revealed weak positive correlation with the Gleason score in cancer and no difference between benign and malignant specimens. Immunohistochemical analysis of tissue sections (N = 12) and microarrays (N = 128 specimens) demonstrated the presence of CDH13 on the apical surface and at intercellular contacts of cytokeratin 8-positive luminal cells and cells double-positive for cytokeratin 8 and basal marker p63. T-cadherin protein expression was markedly upregulated in cancer as compared to benign prostate hyperplasia, the increase being more prominent in organ-confined than in advanced hormone-resistant tumours, and correlated negatively with the Gleason pattern. T-cadherin protein level correlated strongly with cytokeratin 8 and with an abnormal diffuse/membrane localisation pattern of p63. Ectopic expression of CDH13 in metastatic prostate cancer cell line DU145 reduced cell growth in the presence of doxorubicin. We conclude that CDH13 protein, but not its gene expression, is strongly upregulated in early prostate cancer, correlates with changes in luminal/basal differentiation and p63 localisation, and promotes sensitivity of cancer cells to doxorubicin. These data identify CDH13 as a novel molecule relevant for prostate cancer progression and response to therapy.

Cadherin-11 Is a Cell Surface Marker Up-Regulated in Activated Pancreatic Stellate Cells and Is Involved in Pancreatic Cancer Cell Migration

Chronic pancreatitis is a prominent risk factor for the development of pancreatic ductal adenocarcinoma. In both conditions, the activation of myofibroblast-like pancreatic stellate cells (PSCs) plays a predominant role in the formation of desmoplastic reaction through the synthesis of connective tissue and extracellular matrix, inducing local pancreatic fibrosis and an inflammatory response. Yet the signaling events involved in chronic pancreatitis and pancreatic cancer progression and metastasis remain poorly defined. Cadherin-11 (Cad-11, also known as OB cadherin or CDH11) is a cell-to-cell adhesion molecule implicated in many biological functions, including tissue morphogenesis and architecture, extracellular matrix-mediated tissue remodeling, cytoskeletal organization, epithelial-to-mesenchymal transition, and cellular migration. In this study, we show that, in human chronic pancreatitis and pancreatic cancer tissues, Cad-11 expression was significantly increased in PSCs and pancreatic cancer cells. In particular, an increased expression of Cad-11 can be detected on the plasma membrane of activated PSCs isolated from chronic pancreatitis tissues and in pancreatic cancer cells metastasized to the liver. Moreover, knockdown of Cad-11 in cancer cells reduced pancreatic cancer cell migration. Taken together, our data underline the potential role of Cad-11 in PSC activation and pancreatic cancer metastasis.

Cadherin-11 expression is upregulated in invasive human breast cancer

Loss of expression of cadherin-11 protein is correlated with a loss of epithelial phenotype and a gain in tumor cell proliferation and invasion. It has been hypothesized that cadherin-11 may be a molecular marker for a more aggressive subtype of breast cancer. The present study examined the expression of the mesenchymal gene/protein cadherin-11 in malignant, benign and healthy breast cancer samples. A paraffin-embedded tissue microarray of both malignant and benign/healthy breast tumor was used. Clinicopathological parameters, including age, grading, tumor size, hormone receptors and HER2 receptors status were obtained from patient medical records. Expression of cadherin-11 was analyzed using the monoclonal mouse anti cadherin-11 IgG2B clone. Total RNA was extracted from each breast cancer sample and subjected to semi-quantitative RT-PCR analysis for cadherin-11. Cadherin-11 was detected in 80/82 malignant breast cancer samples and in 33/70 non-malignant tissue samples. Cadherin-11 expression was observed to be predominantly localized to the membrane of tumor cells. When compared to healthy breast tissue biopsies, both cadherin-11 mRNA and protein were demonstrated to be significantly overexpressed in breast carcinoma (P=0.040 and P<0.0001, respectively). Within malignant tumors, however, protein expression was not identified to be associated with other clinicopathological parameters. Our results indicate that cadherin-11 expression is upregulated in malignant human breast cancer.

Snail1 expression in human colon cancer DLD-1 cells confers invasive properties without N-cadherin expression

The epithelial-mesenchymal transition (EMT) is a fundamental characteristic of carcinoma cells. EMT is generally associated with a change in cellular morphology from cobblestone to spindle shape, reduced expression of epithelial markers such as E-cadherin, and enhanced expression of mesenchymal markers such as N-cadherin. This EMT-associated reciprocal expression of E-cadherin and N-cadherin has been called the "cadherin switch". Downregulation of E-cadherin enables cells to dissociate from colonies while upregulation of N-cadherin is associated with increased invasiveness. The transcription factor Snail1 induces these changes in various epithelial cell lines, including canine MDCK cells and human A431 cells. In the present study, we introduced a Snail1 expression vector into human DLD-1 cells and isolated stable transfectants. These cells showed changes in morphology, reduced expression of epithelial marker E-cadherin and occludin, and elevated invasion and migration. However, neither expression of N-cadherin protein nor its corresponding mRNA was detected. Therefore, elevated N-cadherin expression is not required for invasiveness of the cells.

Morphological and immunohistochemical identification of epithelial-to-mesenchymal transition in clinical prostate cancer

Epithelial-to-mesenchymal transition (EMT) is a process known to be associated with aggressive tumor behavior, metastasis and treatment resistance. It is characterized by coincidental upregulation of mesenchymal markers such as vimentin, fibronectin and N-cadherin concurrent with E-cadherin downregulation. Studies on EMT are generally performed in cell lines and mouse models, while the histopathological and phenotypical properties in clinical prostate cancer (PCa) are still unclear.

The objective of this study was to identify EMT in PCa patients. We demonstrated that N-cadherin, vimentin and fibronectin were generally not co-expressed in corresponding tumor regions. Immunofluorescent double stainings confirmed that co-expression of mesenchymal markers was uncommon, as we found no prostate cancer cells that co-expressed N-cadherin with fibronectin and only rare (<1%) cells that co-expressed N-cadherin with vimentin. Downregulation of E-cadherin was demonstrated in all N-cadherin positive tumor cells, but not in vimentin or fibronectin positive tumor cells. We further analyzed N-cadherin expression in morphologically distinct PCa growth patterns in a radical prostatectomy cohort (n = 77) and found that N-cadherin is preferentially expressed in ill-defined Gleason grade 4 PCa. In conclusion, we demonstrate that N-cadherin is the most reliable marker for EMT in clinical PCa and is preferentially expressed in ill-defined Gleason grade 4 growth pattern.

Collagen triple helix repeat containing 1 is a new promigratory marker of arthritic pannus

BACKGROUND

The formation of destructive hypercellular pannus is critical to joint damage in rheumatoid arthritis (RA). The collagen triple helix repeat containing 1 (CTHRC1) protein expressed by activated stromal cells of diverse origin has previously been implicated in tissue remodeling and carcinogenesis. We recently discovered that the synovial Cthrc1 mRNA directly correlates with arthritis severity in mice. This study characterizes the role of CTHRC1 in arthritic pannus formation.

METHODS

Synovial joints of mice with collagen antibody-induced arthritis (CAIA) and human RA-fibroblast-like synoviocytes (FLS) were immunostained for CTHRC1, FLS and macrophage-specific markers. CTHRC1 levels in plasma from patients with RA were measured using sandwich ELISA. The migratory response of fibroblasts was studied with a transwell migration assay and time-lapse microscopy. Velocity and directness of cell migration was analyzed by recording the trajectories of cells treated with rhCTHRC1.

RESULTS

Immunohistochemical analysis of normal and inflamed synovium revealed highly inducible expression of CTHRC1 in arthritis (10.9-fold). At the tissue level, CTHRC1-expressing cells occupied the same niche as large fibroblast-like cells positive for α-smooth muscle actin (α-SMA) and cadherin 11 (CDH11). CTHRC1 was produced by activated FLS predominantly located at the synovial intimal lining and at the bone-pannus interface. Cultured RA-FLS expressed CDH11, α-SMA, and CTHRC1. Upon treatment with exogenous rhCTHRC1, embryonic fibroblasts and RA-FLS significantly increased migration velocity, directness, and cell length along the front-tail axis (1.4-fold, p < 0.01).

CONCLUSION

CTHRC1 was established as a novel marker of activated synoviocytes in murine experimental arthritis and RA. The pro-migratory effect of CTHRC1 on synoviocytes is considered one of the mechanisms promoting hypercellularity of the arthritic pannus.

CDH11 inhibits proliferation and invasion in head and neck cancer

BACKGROUND

In this study, we use a bioinformatics-based strategy to nominate a tumor suppressor gene cadherin-11 (CDH11) and investigate its role in growth and invasion in head and neck squamous cell carcinoma (HNSCC).

METHODS

Using the Oncomine^™ database to compare HNSCC and normal specimens, CDH11 was nominated as having a role in HNSCC. CDH11 expression in HNSCC was evaluated by immunohistochemistry on a tissue microarray (TMA) and immunoblotting and immunofluorescence of cell lines. The functional impact of CDH11 on proliferation and invasion was evaluated after siRNA-mediated knockdown.

RESULTS

In silico analysis suggested that CDH11 is overexpressed in HNSCC compared to normal specimens. HNSCC TMA exhibited a small but significant increase in intensity and proportion of CDH11. By immunoblot analysis, CDH11 was higher in 4/7 HNSCC cell lines compared to normal keratinocytes; CDH11 was highly upregulated in UM-SCC-47 and UM-SCC-74A and detectable in UM-SCC-14A and UM-SCC-29 cell lines. Downregulation of CDH11 in both UM-SCC-29 and UM-SCC-47 using two different siRNAs enhanced proliferation and invasion.

CONCLUSION

CDH11 inhibits cell proliferation and invasion of HNSCC. This suggests that CDH11 functions as a tumor suppressor gene in head and neck cancer. Our findings emphasize the importance of verifying in silico findings with functional studies.

Bone Metastasis from Renal Cell Carcinoma

About one-third of patients with advanced renal cell carcinoma (RCC) have bone metastasis that are often osteolytic and cause substantial morbidity, such as pain, pathologic fracture, spinal cord compression and hypercalcemia. The presence of bone metastasis in RCC is also associated with poor prognosis. Bone-targeted treatment using bisphosphonate and denosumab can reduce skeletal complications in RCC, but does not cure the disease or improve survival. Elucidating the molecular mechanisms of tumor-induced changes in the bone microenvironment is needed to develop effective treatment. The “vicious cycle” hypothesis has been used to describe how tumor cells interact with the bone microenvironment to drive bone destruction and tumor growth. Tumor cells secrete factors like parathyroid hormone-related peptide, transforming growth factor-β and vascular endothelial growth factor, which stimulate osteoblasts and increase the production of the receptor activator of nuclear factor κB ligand (RANKL). In turn, the overexpression of RANKL leads to increased osteoclast formation, activation and survival, thereby enhancing bone resorption. This review presents a general survey on bone metastasis in RCC by natural history, interaction among the immune system, bone and tumor, molecular mechanisms, bone turnover markers, therapies and healthcare burden.

Cadherin-11 Overexpression Induces Extracellular Matrix Remodeling and Calcification in Mature Aortic Valves

OBJECTIVE

Calcific aortic valve (AoV) disease is a significant clinical problem for which the regulatory mechanisms are poorly understood. Enhanced cell-cell adhesion is a common mechanism of cellular aggregation, but its role in calcific lesion formation is not known. Cadherin-11 (Cad-11) has been associated with lesion formation in vitro, but its function during adult valve homeostasis and pathogenesis is not known. This study aims to elucidate the specific functions of Cad-11 and its downstream targets, RhoA and Sox9, in extracellular matrix remodeling and AoV calcification.

APPROACH AND RESULTS

We conditionally overexpressed Cad-11 in murine heart valves using a novel double-transgenic Nfatc1(Cre);R26-Cad11(TglTg) mouse model. These mice developed hemodynamically significant aortic stenosis with prominent calcific lesions in the AoV leaflets. Cad-11 overexpression upregulated downstream targets, RhoA and Sox9, in the valve interstitial cells, causing calcification and extensive pathogenic extracellular matrix remodeling. AoV interstitial cells overexpressing Cad-11 in an osteogenic environment in vitro rapidly form calcific nodules analogous to in vivo lesions. Molecular analyses revealed upregulation of osteoblastic and myofibroblastic markers. Treatment with a Rho-associated protein kinase inhibitor attenuated nodule formation, further supporting that Cad-11-driven calcification acts through the small GTPase RhoA/Rho-associated protein kinase signaling pathway.

CONCLUSIONS

This study identifies one of the underlying molecular mechanisms of heart valve calcification and demonstrates that overexpression of Cad-11 upregulates RhoA and Sox9 to induce calcification and extracellular matrix remodeling in adult AoV pathogenesis. The findings provide a potential molecular target for clinical treatment.

Tasquinimod inhibits prostate cancer growth in bone through alterations in the bone microenvironment

BACKGROUND

Tasquinimod (ABR-215050) is an orally active quinoline-3-carboxamide analog that inhibits occurrence of experimental metastasis and delays disease progression of castration resistant prostate cancer in humans. Its mechanism of action is not fully elucidated, but previous studies show immunomodulatory and anti-angiogenic effects. The aim of the present study was to investigate the tumor inhibiting effect of tasquinimod in bone of castrated mice as well as to elucidate its working mechanism related to bone microenvironment.

METHODS

Effects of tasquinimod on prostate cancer metastasis to bone was studied in an intratibial xenograft model. Animals were treated with tasquinimod and tumor establishment and growth, immunological status, as well as markers for bone remodeling were analyzed. Direct effects of tasquinimod on osteoblasts were studied in vitro.

RESULTS

Establishment and growth of tumors in the bone after intratibial implantation in castrated mice was suppressed by tasquinimod treatment. The treatment effect was linked to decreased potential for immunosuppression in the pre-metastatic niche in bone (lower levels of CD206 and Arg1 expression in combination with increased iNOS expression) as well as in the tumor microenvironment (less Gr1 and CD206 staining). The shift to a pro-inflammatory, anti-tumorigenic milieu was also reflected in serum by increased levels of IFN-γ, CCL4, IL-5, LIX, IP-10, and MCP-1 as well as decreased TGF-β. Tasquinimod treatment also affected expression of factors involved in the pre-metastatic niche in the bone microenvironment (Lox, Cdh2, Cdh11, and Cxcl12). In addition, tasquinimod treatment caused a decreased osteogenic response indicated by decreased expression of Ocn, Runx2, and Col1a2 and increased expression of osteoclast stimulating CSF2. In vitro studies on mouse osteoblasts showed impaired osteoblast mineralization upon tasquinimod treatment.

CONCLUSIONS

The present study shows that tasquinimod reduces establishment and progression of tumor growth in bone likely through a combination of effects on the pre-metastatic niche, homing, immunological status, and osteogenesis. It was concluded that tasquinimod interferes with the metastatic process, presumably by inhibition of tumor establishment. Hence, our data suggest that tasquinimod might be most effective in inhibiting the occurrence of new metastatic lesions.

Anti-metastatic functions of type 1 interferons: Foundation for the adjuvant therapy of cancer

The anti-tumorigenic effects that type 1 interferons (IFN1) elicited in the in vitro studies prompted consideration of IFN1 as a potent candidate for clinical treatment. Though not all patients responded to IFN1, clinical trials have shown that patients with high risk melanoma, a highly refractory solid malignancy, benefit greatly from intermediate IFN1 treatment in regards to relapse-free and distant-metastasis-free survival. The mechanisms by which IFN1 treatment at early stages of disease suppress tumor recurrence or metastatic incidence are not fully understood. Intracellular IFN1 signaling is known to affect cell differentiation, proliferation, and apoptosis. Moreover, recent studies have revealed specific IFN1-regulated genes that may contribute to IFN1-mediated suppression of cancer progression and metastasis. In concert, expression of these different IFN1 stimulated genes may impede numerous mechanisms that mediate metastatic process. Though, IFN1 treatment is still utilized as part of standard care for metastatic melanoma (alone or in combination with other therapies), cancers find the ways to develop insensitivity to IFN1 treatment allowing for unconstrained disease progression. To determine how and when IFN1 treatment would be most efficacious during disease progression, we must understand how IFN1 signaling affects different metastasis steps. Here, we specifically focus on the anti-metastatic role of endogenous IFN1 and parameters that may help to use pharmaceutical IFN1 in the adjuvant treatment to prevent cancer recurrence and metastatic disease.