Cadherin-11 promotes the metastasis of prostate cancer cells to bone

BIGH3 mediates apoptosis and gap junction failure in osteocytes during renal cell carcinoma bone metastasis progression

Renal cell carcinoma (RCC) bone metastatis progression is driven by crosstalk between tumor cells and the bone microenvironment, which includes osteoblasts, osteoclasts, and osteocytes. RCC bone metastases (RCCBM) are predominantly osteolytic and resistant to antiresorptive therapy. The molecular mechanisms underlying pathologic osteolysis and disruption of bone homeostasis remain incompletely understood. We previously reported that BIGH3/TGFBI (transforming growth factor-beta-induced protein ig-h3, shortened to BIGH3 henceforth) secreted by colonizing RCC cells drives osteolysis by inhibiting osteoblast differentiation, impairing healing of osteolytic lesions, which is reversible with osteoanabolic agents. Here, we report that BIGH3 induces osteocyte apoptosis in both human RCCBM tissue specimens and in a preclinical mouse model. We also demonstrate that BIGH3 reduces Cx43 expression, blocking gap junction (GJ) function and osteocyte network communication. BIGH3-mediated GJ inhibition is blocked by the lysosomal inhibitor hydroxychloroquine (HCQ), but not osteoanabolic agents. Our results broaden the understanding of pathologic osteolysis in RCCBM and indicate that targeting the BIGH3 mechanism could be a combinational strategy for the treatment of RCCBM-induced bone disease that overcomes the limited efficacy of antiresorptives that target osteoclasts.

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.

Single-cell analysis extracted CAFs-related genes to established online app to predict clinical outcome and radiotherapy prognosis of prostate cancer

BACKGROUND

Cancer-associated fibroblasts (CAFs) play a significant role in regulating the clinical outcome and radiotherapy prognosis of prostate cancer (PCa). The aim of this study is to identify CAFs-related genes (CAFsRGs) using single-cell analysis and evaluate their potential for predicting the prognosis and radiotherapy prognosis in PCa.

METHODS

We acquire transcriptome and single-cell RNA sequencing (scRNA-seq) results of PCa and normal adjacent tissues from The GEO and TCGA databases. The "MCPcounter" and "EPIC" R packages were used to assess the infiltration level of CAFs and examine their correlation with PCa prognosis. ScRNA-seq and differential gene expression analyses were used to extract CAFsRGs. We also applied COX and LASSO analysis to further construct a risk score (CAFsRS) to assess biochemical recurrence-free survival (BRFS) and radiotherapy prognosis of PCa. The predictive efficacy of CAFsRS was evaluated by ROC curves and subgroup analysis. Finally, we integrated the CAFsRS gene signature with relevant clinical features to develop a nomogram, enhancing the predictive accuracy.

RESULTS

The abundance of CAFs is associated with a poor prognosis of PCa patients. ScRNA-seq and differential gene expression analysis revealed 323 CAFsRGs. After COX and LASSO analysis, we obtained seven CAFsRGs with prognostic significance (PTGS2, FKBP10, ENG, CDH11, COL5A1, COL5A2, and SRD5A2). Additionally, we established a risk score model based on the training set (n = 257). The ROC curve was used to confirm the performance of CAFsRS (The AUC values for 1, 3 and 5-year survival were determined to be 0.732, 0.773, and 0.775, respectively.). The testing set (n = 129), GSE70770 set (n = 199) and GSE116918 set (n = 248) revealed that the model exhibited exceptional predictive performance. This was also confirmed by clinical subgroup analysis. The violin plot demonstrated a statistically significant disparity in the CAFs infiltrations between the high-risk and low-risk groups of CAFsRS. Further analysis confirmed that both CAFsRS and T stage were independent prognostic factors for PCa. The nomogram was then established and its excellent predictive performance was demonstrated through calibration and ROC curves. Finally, we developed an online prognostic prediction app ( https://sysu-symh-cafsnomogram.streamlit.app/ ) to facilitate the practical application of the nomogram.

CONCLUSIONS

The prognostic prediction risk score model we constructed could accurately predict BRFS and radiotherapy prognosis PCa, which can provide new ideas for clinicians to develop personalized PCa treatment and follow-up programs.

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.

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.

α-catenin interaction with YAP/FoxM1/TEAD-induced CEP55 supports liver cancer cell migration

BACKGROUND

Adherens junctions (AJs) facilitate cell-cell contact and contribute to cellular communication as well as signaling under physiological and pathological conditions. Aberrant expression of AJ proteins is frequently observed in human cancers; however, how these factors contribute to tumorigenesis is poorly understood. In addition, for some factors such as α-catenin contradicting data has been described. In this study we aim to decipher how the AJ constituent α-catenin contributes to liver cancer formation.

METHODS

TCGA data was used to detect transcript changes in 23 human tumor types. For the detection of proteins, liver cancer tissue microarrays were analyzed by immunohistochemistry. Liver cancer cell lines (HLF, Hep3B, HepG2) were used for viability, proliferation, and migration analyses after RNAinterference-mediated gene silencing. To investigate the tumor initiating potential, vectors coding for α-catenin and myristoylated AKT were injected in mice by hydrodynamic gene delivery. A BioID assay combined with mass spectrometry was performed to identify α-catenin binding partners. Results were confirmed by proximity ligation and co-immunoprecipitation assays. Binding of transcriptional regulators at gene promoters was investigated using chromatin-immunoprecipitation.

RESULTS

α-catenin mRNA was significantly reduced in many human malignancies (e.g., colon adenocarcinoma). In contrast, elevated α-catenin expression in other cancer entities was associated with poor clinical outcome (e.g., for hepatocellular carcinoma; HCC). In HCC cells, α-catenin was detectable at the membrane as well as cytoplasm where it supported tumor cell proliferation and migration. In vivo, α-catenin facilitated moderate oncogenic properties in conjunction with AKT overexpression. Cytokinesis regulator centrosomal protein 55 (CEP55) was identified as a novel α-catenin-binding protein in the cytoplasm of HCC cells. The physical interaction between α-catenin and CEP55 was associated with CEP55 stabilization. CEP55 was highly expressed in human HCC tissues and its overexpression correlated with poor overall survival and cancer recurrence. Next to the α-catenin-dependent protein stabilization, CEP55 was transcriptionally induced by a complex consisting of TEA domain transcription factors (TEADs), forkhead box M1 (FoxM1), and yes-associated protein (YAP). Surprisingly, CEP55 did not affect HCC cell proliferation but significantly supported migration in conjunction with α-catenin.

CONCLUSION

Migration-supporting CEP55 is induced by two independent mechanisms in HCC cells: stabilization through interaction with the AJ protein α-catenin and transcriptional activation via the FoxM1/TEAD/YAP complex.

Awakening of Dormant Breast Cancer Cells in the Bone Marrow

Up to 40% of patients with breast cancer (BC) have metastatic cells in the bone marrow (BM) at the initial diagnosis of localized disease. Despite definitive systemic adjuvant therapy, these cells survive in the BM microenvironment, enter a dormant state and recur stochastically for more than 20 years. Once they begin to proliferate, recurrent macrometastases are not curable, and patients generally succumb to their disease. Many potential mechanisms for initiating recurrence have been proposed, but no definitive predictive data have been generated. This manuscript reviews the proposed mechanisms that maintain BC cell dormancy in the BM microenvironment and discusses the data supporting specific mechanisms for recurrence. It addresses the well-described mechanisms of secretory senescence, inflammation, aging, adipogenic BM conversion, autophagy, systemic effects of trauma and surgery, sympathetic signaling, transient angiogenic bursts, hypercoagulable states, osteoclast activation, and epigenetic modifications of dormant cells. This review addresses proposed approaches for either eliminating micrometastases or maintaining a dormant state.

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.

Cancer stem cell in prostate cancer progression, metastasis and therapy resistance

Prostate cancer (PCa) is the most diagnosed malignancy in the men worldwide. Cancer stem cells (CSCs) are the sub-population of cells present in the tumor which possess unique properties of self-renewal and multilineage differentiation thus thought to be major cause of therapy resistance, disease relapse, and mortality in several malignancies including PCa. CSCs have also been shown positive for the common stem cells markers such as ALDH EZH2, OCT4, SOX2, c-MYC, Nanog etc. Therefore, isolation and characterization of CSCs specific markers which may discriminate CSCs and normal stem cells are critical to selectively eliminate CSCs. Rapid advances in the field offers a theoretical explanation for many of the enduring uncertainties encompassing the etiology and an optimism for the identification of new stem-cell targets, development of reliable and efficient therapies in the future. The emerging reports have also provided unprecedented insights into CSCs plasticity, quiescence, renewal, and therapeutic response. In this review, we discuss the identification of PCa stem cells, their unique properties, stemness-driving pathways, new diagnostics, and therapeutic interventions.

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.

Activated Src requires Cadherin-11, Rac, and gp130 for Stat3 activation and survival of mouse Balb/c3T3 fibroblasts

We previously demonstrated that engagement of cadherins, cell to cell adhesion molecules, triggers a dramatic increase in levels and activity of the Rac/Cdc42 small GTPases, which is followed by secretion of IL6 family cytokines and activation of their common receptor, gp130, in an autocrine manner. This results in phosphorylation of the Signal Transducer and Activator of Transcription-3 (Stat3) on tyrosine-705, which then dimerizes, migrates to the nucleus, and activates transcription of genes involved in cell division and survival. In the present report we demonstrate that, in mouse Balb/c3T3 fibroblasts, mutationally activated Src527F also increases Rac levels, leading to secretion of IL6 family cytokines and gp130 activation, which triggers the Stat3-ptyr705 increase. Interestingly, our results also demonstrate that cadherin-11 is required to preserve gp130 levels for IL6 family signaling. At the same time, however, activated Src527F downregulates cadherin-11, in a quantitative manner. As a result, Src527F expression to intermediate levels allows sufficient cadherin-11, hence gp130 levels for Stat3 activation, as expected. However, expressed to high levels, Src527F eliminates cadherin-11, hence gp130 signaling, thus abolishing Stat3-ptyr705 stimulation. Taken together, these data establish for the first time a loop between Src, cadherin-11, gp130, and Stat3 activation. This fine balance between Src527F and cadherin-11 levels which is required for Stat3 activation and cellular survival could have significant therapeutic implications.

microRNA-145-5p inhibits prostate cancer bone metastatic by modulating the epithelial-mesenchymal transition

Objective

To investigate the effects of miRNA-145-5p on the tumor development and progression of prostate cancer (Pca) bone metastasis.

Methods

Levels of miRNA-145-5p were assessed by real-time quantitative PCR in PC3 (bone metastatic Pca cells), 22RV1 (non-metastatic Pca cells), RWPE-1 (non-cancerous prostate epithelial cells) and Pca tissues collected from patients with and without bone metastases. The impact of miRNA-145-5p on cell proliferation was tested by CCK8 assay, colony formation assay and flow cytometric cell cycle analysis. Effects on invasion and migration of PC3 cells were determined by Transwell and wound healing assays. Western blotting, enzyme-linked immunosorbent assay, and flow cytometry apoptosis analyses were also performed to assess roles in metastasis.

Results

Levels of miRNA-145-5p were decreased in Pca bone metastases and miRNA-145-5p inhibited cell proliferation, migration and invasion. miRNA-145-5p inhibited the expression of basic fibroblast growth factor (bFGF), insulin-like growth factor (IGF) and transforming growth factor-β (TGF-β) in PC3 cells. miR-145-5p increased the expression of the epithelial marker E-cadherin and reduced the expression of matrix metalloproteinase 2 and 9 (MMP-2 and MMP-9). It was found that miRNA-145-5p mediated the epithelial-mesenchymal transition (EMT) and induced apoptosis.

Conclusions

miRNA-145-5p negatively regulated the EMT, inhibited Pca bone metastasis and promoted apoptosis in Pca bone metastasis. Mimicry of miRNA-145-5p action raises the possibility of a novel target for treating Pca with bone metastases.

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.

Tumor cell-derived ANGPTL2 promotes β-catenin-driven intestinal tumorigenesis

Uncontrolled proliferation of intestinal epithelial cells caused by mutations in genes of the WNT/β-catenin pathway is associated with development of intestinal cancers. We previously reported that intestinal stromal cell-derived angiopoietin-like protein 2 (ANGPTL2) controls epithelial regeneration and intestinal immune responses. However, the role of tumor cell-derived ANGPTL2 in intestinal tumorigenesis remained unclear. Here, we show that tumor cell-derived ANGPTL2 promotes β-catenin-driven intestinal tumorigenesis. ANGPTL2 deficiency suppressed intestinal tumor development in an experimental mouse model of sporadic colon cancer. We also found that increased ANGPTL2 expression in colorectal cancer (CRC) cells augments β-catenin pathway signaling and promotes tumor cell proliferation. Relevant to mechanism, our findings suggest that tumor cell-derived ANGPTL2 upregulates expression of OB-cadherin, which then interacts with β-catenin, blocking destruction complex-independent proteasomal degradation of β-catenin proteins. Moreover, our observations support a model whereby ANGPTL2-induced OB-cadherin expression in CRC cells is accompanied by decreased cell surface integrin α5β1 expression. These findings overall provide novel insight into mechanisms of β-catenin-driven intestinal tumorigenesis.

A Novel Overall Survival Prediction Signature Based on Comprehensive Research in Prostate Cancer Bone Metastases

BACKGROUND

Prostate adenocarcinoma (PRAD)-related bone metastases are a leading source of morbidity and mortality; however, good diagnostic biomarkers are not known yet. The aim of this study was to identify biomarkers and prognostic indicators for the diagnosis and treatment of PRAD-associated bone metastases.

METHODS

By combining the data from The Cancer Genome Atlas(TCGA) and PRAD SU2C 2019, We performed a comprehensive analysis of the expression differences, biological functions, and interactions of genes associated with PRAD bone metastasis. Annotation, visualization, and integrated discovery were accomplished through the use of gene ontology enrichment and gene set enrichment analysis. The protein-protein interaction network was constructed using the STRING database, and the diagnostic value of prognostic genes was validated using receiver-operating-characteristic and Kaplan-Meier curves.

RESULTS

Six genes (DDX47, PRL17, AS3MT, KLRK1, ISLR, and S100A8) associated with PRAD bone metastases were identified; these had prognostic value as well. Among them, enrichment was observed for the biological processes extracellular matrix tissue, extracellular structural tissue, steroid hormone response, and cell oxidative detoxification. KEGG analysis revealed enrichment in interactions with extracellular matrix receptors, diseases including Parkinson's disease and dilated cardiomyopathy, and estrogen signaling pathways. The area under the curve values of 0.8938, 0.9885, and 0.979, obtained from time-dependent receiver-operating-characteristic curve analysis for 1, 3, and 5-year overall survival confirmed the good performance of the model under consideration. S100A8 expression was not detected in the normal prostate tissue but was detected in PRAD.

CONCLUSIONS

We identified ISLR as a potential biomarker for PRAD bone metastasis. Moreover, the genes identified to have prognostic value may act as therapeutic targets for PRAD bone metastasis.

Cell Adhesion Molecules in Neuroblastoma: Complex Roles, Therapeutic Potential

Neuroblastoma, a biologically heterogeneous tumor derived from neural crest cells, accounts for approximately 15% of childhood deaths from cancer. Recently, scientific literature has explored the role of cell adhesion molecules (CAMs) in cancer metastasis through cell detachment, migration, and invasion. Through a review of the current literature, it is evident that expression of different CAMs on neuroblastoma tumors is associated with favorable or unfavorable clinical prognosis. In patients diagnosed with neuroblastoma, treatment strategies include chemotherapy, surgery, radiotherapy, stem cell transplant, and more recently, immunotherapy and other targeted therapies. Long term survival remains poor despite multimodality treatment, especially for children with high-risk neuroblastoma, making it more necessary to explore innovative targeted therapies. CAMs have immense potential as therapeutic targets, but there is a need for growth and scientific exploration before CAM therapies become clinically useful.

Cellular plasticity in bone metastasis

Metastasis is responsible for a large majority of death from malignant solid tumors. Bone is one of the most frequently affected organs in cancer metastasis, especially in breast and prostate cancer. Development of bone metastasis requires cancer cells to successfully complete a number of challenging steps, including local invasion and intravasation, survival in circulation, extravasation and initial seeding, and finally, formation of metastatic colonies after a period of dormancy or indolent growth. During this process, cancer cells often undergo a series of cellular and molecular changes to gain cellular plasticity that helps them adapt to various environments they encounter along the journey of metastasis. Understanding the mechanisms behind cellular plasticity and adaptation during the formation of bone metastasis is crucial for the development of novel therapies.

Menin Enhances Androgen Receptor-Independent Proliferation and Migration of Prostate Cancer Cells

The androgen receptor (AR) is an important therapeutic target for treating prostate cancer (PCa). Moreover, there is an increasing need for understanding the AR-independent progression of tumor cells such as neuroendocrine prostate cancer (NEPC). Menin, which is encoded by multiple endocrine neoplasia type 1 (MEN1), serves as a direct link between AR and the mixed-lineage leukemia (MLL) complex in PCa development by activating AR target genes through histone H3 lysine 4 methylation. Although menin is a critical component of AR signaling, its tumorigenic role in AR-independent PCa cells remains unknown. Here, we compared the role of menin in AR-positive and AR-negative PCa cells via RNAi-mediated or pharmacological inhibition of menin. We demonstrated that menin was involved in tumor cell growth and metastasis in PCa cells with low or deficient levels of AR. The inhibition of menin significantly diminished the growth of PCa cells and induced apoptosis, regardless of the presence of AR. Additionally, transcriptome analysis showed that the expression of many metastasis-associated genes was perturbed by menin inhibition in AR-negative DU145 cells. Furthermore, wound-healing assay results showed that menin promoted cell migration in AR-independent cellular contexts. Overall, these findings suggest a critical function of menin in tumorigenesis and provide a rationale for drug development against menin toward targeting high-risk metastatic PCa, especially those independent of AR.

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.

A humanized orthotopic tumor microenvironment alters the bone metastatic tropism of prostate cancer cells

Prostate cancer (PCa) is the second most commonly diagnosed cancer in men, and bone is the most frequent site of metastasis. The tumor microenvironment (TME) impacts tumor growth and metastasis, yet the role of the TME in PCa metastasis to bone is not fully understood. We used a tissue-engineered xenograft approach in NOD-scid IL2Rγ^null (NSG) mice to incorporate two levels of humanization; the primary tumor and TME, and the secondary metastatic bone organ. Bioluminescent imaging, histology, and immunohistochemistry were used to study metastasis of human PC-3 and LNCaP PCa cells from the prostate to tissue-engineered bone. Here we show pre-seeding scaffolds with human osteoblasts increases the human cellular and extracellular matrix content of bone constructs, compared to unseeded scaffolds. The humanized prostate TME showed a trend to decrease metastasis of PC-3 PCa cells to the tissue-engineered bone, but did not affect the metastatic potential of PCa cells to the endogenous murine bones or organs. On the other hand, the humanized TME enhanced LNCaP tumor growth and metastasis to humanized and murine bone. Together this demonstrates the importance of the TME in PCa bone tropism, although further investigations are needed to delineate specific roles of the TME components in this context.

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.

Extracellular Vesicle-Mediated Bone Remodeling and Bone Metastasis: Implications in Prostate Cancer

Bone metastasis is the tendency of certain primary tumors to spawn and dictate secondary neoplasia in the bone. The process of bone metastasis is regulated by the dynamic crosstalk between metastatic cancer cells, cellular components of the bone marrow microenvironment (osteoblasts, osteoclasts, and osteocytes), and the bone matrix. The feed-forward loop mechanisms governs the co-option of homeostatic bone remodeling by cancer cells in bone. Recent developments have highlighted the discovery of extracellular vesicles (EVs) and their diverse roles in distant outgrowths. Several studies have implicated EV-mediated interactions between cancer cells and the bone microenvironment in synergistically promoting pathological skeletal metabolism in the metastatic site. Nevertheless, the potential role that EVs serve in arbitrating intricate sequences of coordinated events within the bone microenvironment remains an emerging field. In this chapter, we review the role of cellular participants and molecular mechanisms in regulating normal bone physiology and explore the progress of current research into bone-derived EVs in directly triggering and coordinating the processes of physiological bone remodeling. In view of the emerging role of EVs in interorgan crosstalk, this review also highlights the multiple systemic pathophysiological processes orchestrated by the EVs to direct organotropism in bone in prostate cancer. Given the deleterious consequences of bone metastasis and its clinical importance, in-depth knowledge of the multifarious role of EVs in distant organ metastasis is expected to open new possibilities for prognostic evaluation and therapeutic intervention for advanced bone metastatic prostate cancer.

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.

Circulating prostate cancer cells have differential resistance to fluid shear stress-induced cell death

Circulating tumor cells (CTCs) are exposed to fluid shear stress (FSS) of greater than 1000 dyn/cm² (100 Pa) in circulation. Normally, CTCs that are exposed to FSS of this magnitude die. However, some CTCs develop resistance to this FSS, allowing them to colonize distant organs. We explored how prostate CTCs can resist cell death in response to forces of this magnitude. The DU145, PC3 and LNCaP human prostate cancer cell lines were used to represent cells of different metastatic origins. The cell lines were briefly treated with an average FSS of 3950 dyn/cm² (395 Pa) using a 30 G needle and a syringe pump. DU145 cells had no change in cell viability, PC3 cells had some cell death and LNCaP cells exhibited significant cell death. These cell death responses correlated with increased cell membrane damage, less efficient membrane repair and increased stiffness. Additionally, FSS treatment prevented the LNCaP FSS-sensitive cell line from forming a growing tumor in vivo. This suggests that these properties play a role in FSS resistance and could represent potential targets for disrupting blood-borne metastasis.

Summary: Prostate cancer cells have different sensitivities to fluid forces that alter their resistance to elevated blood flow-level fluid shear stress.

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.

Causes, effects, and clinical implications of perturbed patterns within the cancer epigenome

Somatic mutations accumulating over a patient's lifetime are well-defined causative factors that fuel carcinogenesis. It is now clear, however, that epigenomic signature is also largely perturbed in many malignancies. These alterations support the transcriptional program crucial for the acquisition and maintenance of cancer hallmarks. Epigenetic instability may arise due to the genetic mutations or transcriptional deregulation of the proteins implicated in epigenetic signaling. Moreover, external stimulation and physiological aging may also participate in this phenomenon. The epigenomic signature is frequently associated with a cell of origin, as well as with tumor stage and differentiation, which all reflect its high heterogeneity across and within various tumors. Here, we will overview the current understanding of the causes and effects of the altered and heterogeneous epigenomic landscape in cancer. We will focus mainly on DNA methylation and post-translational histone modifications as the key regulatory epigenetic signaling marks. In addition, we will describe how this knowledge is translated into the clinic. We will particularly concentrate on the applicability of epigenetic alterations as biomarkers for improved diagnosis, prognosis, and prediction. Finally, we will also review current developments regarding epi-drug usage in clinical and experimental settings.

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.

Cadherin-11 and cardiac fibrosis: A common target for a common pathology

Cardiac fibrosis represents an enormous health concern as it is prevalent in nearly every form of cardiovascular disease, the leading cause of death worldwide. Fibrosis is characterized by the activation of fibroblasts into myofibroblasts, a contractile cell type that secretes significant amounts of extracellular matrix components; however, the onset of this condition is also due to persistent inflammation and the cellular responses to a changing mechanical environment. In this review, we provide an overview of the pro-fibrotic, pro-inflammatory, and biomechanical mechanisms that lead to cardiac fibrosis in cardiovascular diseases. We then discuss cadherin-11, an intercellular adhesion protein present on both myofibroblasts and inflammatory cells, as a potential link for all three of the fibrotic mechanisms. Since experimentally blocking cadherin-11 dimerization prevents fibrotic diseases including cardiac fibrosis, understanding how this protein can be targeted for therapeutic use could lead to better treatments for patients with heart disease.

Bone Tropism in Cancer Metastases

Bone is a frequent site of metastases in many cancers. Both bone properties and the tumor-intrinsic traits are associated with the metastatic propensity to bone (i.e., the bone tropism). Whereas an increasing body of mechanistic studies expanded our understanding on bone tropism, they also revealed complexity across the bone lesions originated from different cancer types. In this review, we will discuss the physical, chemical, and biological properties of bone microenvironment, identify potential players in every stage of bone metastases, and introduce some of the known mechanisms regulating the bone colonization. Our objectives are to integrate the knowledge established in different biological contexts and highlight the determinants of bone tropism.

Macrophages and cadherins in fibrosis and systemic sclerosis

PURPOSE OF REVIEW

Macrophages are key players in systemic sclerosis (SSc) and fibrosis. The mechanism by which macrophages regulate fibrogenesis is unclear and understanding the origin and function of macrophages is critical to developing effective therapeutics. Novel targets on macrophages are under investigation and recently, cadherins have emerged as a potential therapeutic target on macrophages. The current review will discuss the importance of macrophages in SSc and fibrosis and summarize recent studies on the role of cadherin-11 (Cdh11) on macrophages and fibrosis.

RECENT FINDINGS

Genome-wide expression studies demonstrate the importance of macrophages in SSc and fibrosis. Although M2 macrophages are associated with fibrosis, the presence of a mixed M1/M2 phenotype in fibrosis has recently been reported. Several studies aiming to identify macrophage subsets involved in fibrogenesis suggest that monocyte-derived alveolar macrophages are key players in the development of murine lung fibrosis. Recent functional studies show that Cdh11 regulates macrophages, fibroblast invasion, and adhesion of macrophages to myofibroblasts.

SUMMARY

Macrophages play an important role in SSc and fibrosis. New insights into the mechanisms by which macrophages regulate fibrogenesis have been discovered on the basis of Cdh11 studies and suggest that targeting Cdh11 may be an effective target to treat fibrosis.

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.

Cadherin-11 Is a Regulator of Intestinal Fibrosis

BACKGROUND AND AIMS

Although the mechanisms underlying the formation of intestinal fibrostrictures in Crohn's disease [CD] are not fully understood, activation of fibroblasts and excessive collagen deposition are supposed to contribute to the development of such complications. Here, we investigated the role of cadherin-11 [CDH-11], a fibroblast-derived protein that induces collagen production in various organs, in intestinal fibrosis.

METHODS

CDH-11 expression was evaluated in inflammatory [I] and fibrostricturing [FS] CD mucosal samples, ulcerative colitis [UC] mucosal samples, and ileal and colonic control samples, by real-time polymerase chain reaction, western blotting, and immunohistochemistry. CDH-11 expression was evaluated in normal and in CD intestinal fibroblasts stimulated with inflammatory/fibrogenic cytokines. FS CD fibroblasts were cultured either with a specific CDH-11 antisense oligonucleotide [AS], or activating CDH-11 fusion protein and activation of RhoA/ROCK, and TGF-β pathways and collagen production were evaluated by western blotting. Finally, we assessed the susceptibility of CDH-11-knockout [KO] mice to colitis-induced intestinal fibrosis.

RESULTS

CDH-11 RNA and protein expression were increased in both CD and UC as compared with controls. In CD, the greater expression of CDH-11 was seen in FS samples. Stimulation of fibroblasts with TNF-α, interleukin [IL]-6, IFN-γ, IL-13, and IL-1β enhanced CDH-11 expression. Knockdown of CDH-11 in FS CD fibroblasts impaired RhoA/ROCK/TGF-β signalling and reduced collagen synthesis, whereas activation of CDH-11 increased collagen secretion. CDH-11 KO mice were largely protected from intestinal fibrosis.

CONCLUSIONS

Data show that CDH-11 expression is up-regulated in inflammatory bowel disease [IBD] and suggest a role for this protein in the control of intestinal fibrosis.

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.

Humanized bone facilitates prostate cancer metastasis and recapitulates therapeutic effects of zoledronic acid in vivo

Advanced prostate cancer (PCa) is known for its high prevalence to metastasize to bone, at which point it is considered incurable. Despite significant effort, there is no animal model capable of recapitulating the complexity of PCa bone metastasis. The humanized mouse model for PCa bone metastasis used in this study aims to provide a platform for the assessment of new drugs by recapitulating the human-human cell interactions relevant for disease development and progression. The humanized tissue-engineered bone construct (hTEBC) was created within NOD-scid IL2rgnull (NSG) mice and was used for the study of experimental PC3-Luc bone metastases. It was confirmed that PC3-Luc cells preferentially grew in the hTEBC compared with murine bone. The translational potential of the humanized mouse model for PCa bone metastasis was evaluated with two clinically approved osteoprotective therapies, the non-species-specific bisphosphonate zoledronic acid (ZA) or the human-specific antibody Denosumab, both targeting Receptor Activator of Nuclear Factor Kappa-Β Ligand. ZA, but not Denosumab, significantly decreased metastases in hTEBCs, but not murine femora. These results highlight the importance of humanized models for the preclinical research on PCa bone metastasis and indicate the potential of the bioengineered mouse model to closely mimic the metastatic cascade of PCa cells to human bone. Eventually, it will enable the development of new effective antimetastatic treatments.

A Multifunctional Therapy Approach for Cancer: Targeting Raf1- Mediated Inhibition of Cell Motility, Growth, and Interaction with the Microenvironment

Prostate cancer cells move from their primary site of origin, interact with a distant microenvironment, grow, and thereby cause death. It had heretofore not been possible to selectively inhibit cancer cell motility. Our group has recently shown that inhibition of intracellular activation of Raf1 with the small-molecule therapeutic KBU2046 permits, for the first time, selective inhibition of cell motility. We hypothesized that simultaneous disruption of multiple distinct functions that drive progression of prostate cancer to induce death would result in advanced disease control. Using a murine orthotopic implantation model of human prostate cancer metastasis, we demonstrate that combined treatment with KBU2046 and docetaxel retains docetaxel's antitumor action, but provides improved inhibition of metastasis, compared with monotherapy. KBU2046 does not interfere with hormone therapy, inclusive of enzalutamide-mediated inhibition of androgen receptor (AR) function and cell growth inhibition, and inclusive of the ability of castration to inhibit LNCaP-AR cell outgrowth in mice. Cell movement is necessary for osteoclast-mediated bone degradation. KBU2046 inhibits Raf1 and its downstream activation of MEK1/2 and ERK1/2 in osteoclasts, inhibiting cytoskeleton rearrangement, resorptive cavity formation, and bone destruction in vitro, with improved effects observed when the bone microenvironment is chemically modified by pretreatment with zoledronic acid. Using a murine cardiac injection model of human prostate cancer bone destruction quantified by CT, KBU2046 plus zoledronic exhibit improved inhibitory efficacy, compared with monotherapy. The combined disruption of pathways that drive cell movement, interaction with bone, and growth constitutes a multifunctional targeting strategy that provides advanced disease control.

Effect of CD133 overexpression on bone metastasis in prostate cancer cell line LNCaP

Prostate cancer (PC) metastasizes to the bone, and a small number of cancer cells, described as cancer stem cells (CSCs), have the ability to differentiate into tumor cells. CSCs are responsible for tumor recurrence and metastases. In the present study, we examined whether ectopic overexpression of CD133, a key molecule maintaining the stability of CSCs in the human PC cell line, LnCaP, caused bone metastasis in a mouse model. Ectopic overexpression of CD133 was induced in LnCaP cells, and CSC-related protein expression was measured. Furthermore, a colony-forming assay was performed to compare results against the blank green fluorescent protein-expressing cells. Furthermore, epithelial to mesenchymal transition-related protein expression, cell migration and wound healing were investigated. To assess the role of CD133 in bone metastasis, CD133-overexpressing LnCaP cells were inoculated into mice via intracardiac injection, and bone metastasis was assessed via histological and immunohistochemical study. In addition, cytokine arrays were used to determine the cytokines involved in bone metastasis. Ectopic overexpression of CD133 in LnCaP cells increased CSC properties such as Oct-4 and Nanog expression and colony-forming ability. Furthermore, epithelial-to-mesenchymal transition (EMT) properties, including decreased E-cadherin and increased vimentin expression, wound gap distance, and cell migration increased. CD133 overexpression led to formation of bone metastatic tumors in mice, consistent with results of hematoxylin and eosin staining. In addition, an increase in expression of the macrophage-migration inhibitory factor was observed at the tumor margin in mice inoculated with CD133⁺ LNCaP cells. These findings suggest a regulatory role of CD133 in stem cell and EMT properties, and the sustained acquisition of osteolytic features in PC. Therefore, our results may facilitate development of a novel classification system and therapeutic strategies for bone metastasis of PC.

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.

Regulation of Osteosclerosis by Inoculated Cd133+ PC3 Cells in Bone-marrow Microenvironmental Niches

Bone is the most common site of prostate cancer (PC) metastasis. Studies suggest that cancer stem cells (CSCs) are associated with stemness characteristics, providing some support for the concept that CSCs act as osteosclerotic precursors in bone microenvironmental niches. Here, we asked whether ectopic overexpression of CD133 maintains stability of CSCs in human PC cell lines and induces the changes of molecular features in the bone microenvironment. Ectopic overexpression of CD133 in PC3 or DU145 cells led to increased expression of ALDHA1, OCT4, and NANOG, enhanced colony‐forming ability, and increased ALDH activity. In addition, micro‐CT imaging, confocal microscopy, and H&E staining of mouse tissue confirmed that CD133 overexpression in PC3 and DU145 led to marked osteolytic bone tumor. However, expression of osteoblastic markers such as collagen type I, bone sialoprotein, and osteocalcin (OC) at the tumor margin of CD133‐overexpressing PC3 tumors in mouse tibiae was higher than that of CD133‐overexpressing DU145 tumors with osteosclerotic molecular features. In addition, expression of osteopontin (OPN) mRNA/protein by CD133‐overexpressing PC3 cells was higher than that by DU145 cells. Especially, conditioned medium (CM) from PC3^CD133+ cells increased osterix (OSX) activity in bone marrow stromal cells (BMSCs), resulting in increased expression of OC mRNA/protein resulted in increased staining of mineralized matrix by Alizarin red. However, CM from OPN silenced PC3^CD133+ cells led to a reduction of OC mRNA and protein expression through OSX activity resulted in reduced amount of mineralized matrix. In conclusion, these findings suggest that CD133 plays a functional role in regulating CSC characteristics in PCs and modulates their abilities in which induce the osteosclerosis of BMSCs. In addition, OPN from CSCs acts as a niche component that promotes osteosclerosis by supporting osteoblastic differentiation of BMSCs. © 2019 The Authors JBMR Plus published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research.

Cross-Talk between Fibroblast Growth Factor Receptors and Other Cell Surface Proteins

Fibroblast growth factors (FGFs) and their receptors (FGFRs) constitute signaling circuits that transmit signals across the plasma membrane, regulating pivotal cellular processes like differentiation, migration, proliferation, and apoptosis. The malfunction of FGFs/FGFRs signaling axis is observed in numerous developmental and metabolic disorders, and in various tumors. The large diversity of FGFs/FGFRs functions is attributed to a great complexity in the regulation of FGFs/FGFRs-dependent signaling cascades. The function of FGFRs is modulated at several levels, including gene expression, alternative splicing, posttranslational modifications, and protein trafficking. One of the emerging ways to adjust FGFRs activity is through formation of complexes with other integral proteins of the cell membrane. These proteins may act as coreceptors, modulating binding of FGFs to FGFRs and defining specificity of elicited cellular response. FGFRs may interact with other cell surface receptors, like G-protein-coupled receptors (GPCRs) or receptor tyrosine kinases (RTKs). The cross-talk between various receptors modulates the strength and specificity of intracellular signaling and cell fate. At the cell surface FGFRs can assemble into large complexes involving various cell adhesion molecules (CAMs). The interplay between FGFRs and CAMs affects cell–cell interaction and motility and is especially important for development of the central nervous system. This review summarizes current stage of knowledge about the regulation of FGFRs by the plasma membrane-embedded partner proteins and highlights the importance of FGFRs-containing membrane complexes in pathological conditions, including cancer.

Transmembrane protein 64 modulates prostate tumor progression by regulating Wnt3a secretion

Wnt3a is a glycosylated ligand that activates the β-catenin-dependent signaling pathway. Wnt signaling is also important in the prostate tumor microenvironment, and Wnt proteins secreted by the tumor stroma promote resistance to therapy. Bioactive Wnt3a production requires a number of dedicated factors in the secretory cell, but their coordinated functions are not fully understood. We previously reported transmembrane protein 64 (Tmem64) as a novel regulator of the Wnt/β-catenin signaling pathway, which is correlated with β-catenin regulation. In the present study, the role of Tmem64 in prostate cancer cells was investigated by modulating Wnt3a secretion. Overexpression of Tmem64 inhibited Wnt3a secretion and Lef/Tcf-sensitive transcription. By contrast, a Tmem64 mutation deleting the protein's transmembrane region restored Wnt3a secretion. Notably, Tmem64 protein and mRNA in PC3 cells were significantly overexpressed compared with that observed in LNCaP and DU145 cells. In a mouse metastasis model intracardially injected with PC3 cells, Tmem64 expression was downregulated in the metastatic spine and mandible lesions compared with in the primary injection regions. However, Wnt3a was strongly expressed in the metastatic spine and mandible lesions. Collectively, these findings suggest that Tmem64 is involved in the metastatic progression of prostate cancer cells by regulating Wnt3a secretion.

Interactions between cadherin-11 and platelet-derived growth factor receptor-alpha signaling link cell adhesion and proliferation

Cadherins are homophilic cell-to-cell adhesion molecules that help cells respond to environmental changes. Newly formed cadherin junctions are associated with increased cell phosphorylation, but the pathways driving this signaling response are largely unknown. Since cadherins have no intrinsic signaling activity, this phosphorylation must occur through interactions with other signaling molecules. We previously reported that cadherin-11 engagement activates joint synovial fibroblasts, promoting inflammatory and degradative pathways important in rheumatoid arthritis (RA) pathogenesis. Our objective in this study was to discover interacting partners that mediate cadherin-11 signaling. Protein array screening showed that cadherin-11 extracellular binding domains linked to an Fc domain (cad11Fc) induced platelet-derived growth factor (PDGFR)-α phosphorylation in synovial fibroblasts and glioblastoma cells. PDGFRs are growth factor receptor tyrosine kinases that promote cell proliferation, survival, and migration in mesodermally derived cells. Increased PDGFR activity is implicated in RA pathology and associates with poor prognosis in several cancers, including sarcoma and glioblastoma. PDGFRα activation by cadherin-11 signaling promoted fibroblast proliferation, a signaling pathway independent from cadherin-11-stimulated IL-6 or matrix metalloproteinase (MMP)-3 release. PDGFRα phosphorylation mediated most of the cad11Fc-induced phosphatidyl-3-kinase (PI3K)/Akt activation, but only part of the mitogen-activated protein kinase (MAPK) response. PDGFRα-dependent signaling did not require cell cadherin-11 expression. Rather, cad11Fc immunoprecipitated PDGFRα, indicating a direct interaction between cadherin-11 and PDGFRα extracellular domains. This study is the first to report an interaction between cadherin-11 and PDGFRα and adds to our growing understanding that cadherin-growth factor receptor interactions help balance the interplay between tissue growth and adhesion.

Prostate cancer metastasis and soy isoflavones: a dogfight over a bone

Prostate cancer is a complex, progressive, bone-tropic disease, which is usually associated with skeletal issues, poor mobility and a fatal outcome when it reaches the metastatic phase. Soy isoflavones, steroid-like compounds from soy-based food/dietary supplements, have been found to decrease the risk of prostate cancer in frequent consumers. Herein, we present a systematization of the data on soy isoflavone effects at different stages of metastatic prostate cancer progression, with a particular interest in the context of bone-related molecular events. Specifically, soy isoflavones have been determined to downregulate the prostate cancer cell androgen receptors, reverse the epithelial to mesenchymal transition of these cells, decrease the expressions of prostate-specific antigen, matrix metalloproteinase and serine proteinase, and reduce the superficial membrane fluidity in prostate cancer cells. In addition, soy isoflavones suppress the angiogenesis that follows prostate cancer growth, obstruct prostate cancer cells adhesion to the vascular endothelium and their extravasation in the area of future bone lesions, improve the general bone morphofunctional status, have a beneficial effect on prostate cancer metastasis-caused osteolytic/osteoblastic lesions and possibly affect the pre-metastatic niche formation. The observed, multilevel antimetastatic properties of soy isoflavones imply that they should be considered as promising components of combined therapeutic approaches to advanced prostate cancer.

Cadherin 11 Inhibition Downregulates β-catenin, Deactivates the Canonical WNT Signalling Pathway and Suppresses the Cancer Stem Cell-Like Phenotype of Triple Negative Breast Cancer

BACKGROUND

Cancer stem cells (CSCs) promote tumor progression and distant metastasis in breast cancer. Cadherin 11 (CDH11) is overexpressed in invasive breast cancer cells and implicated in distant bone metastases in several cancers. The WNT signalling pathway regulates CSC activity. Growing evidence suggest that cadherins play critical roles in WNT signalling pathway. However, CDH11 role in canonical WNT signalling and CSCs in breast cancer is poorly understood.

METHODS

We investigated the functional association between CDH11 and WNT signalling pathway in triple negative breast cancer (TNBC), by analyzing their expression profile in the TCGA Breast Cancer (BRCA) cohort and immunohistochemical (IHC) staining of TNBC samples.

RESULTS

We observed a significant correlation between high CDH11 expression and poor prognosis in the basal and TNBC subtypes. Also, CDH11 expression positively correlated with β-catenin, wingless type MMTV integration site (WNT)2, and transcription factor (TCF)12 expression. IHC results showed CDH11 and β-catenin expression significantly correlated in TNBC patients (p < 0.05). We also showed that siRNA-mediated loss-of-CDH11 (siCDH11) function decreases β-catenin, Met, c-Myc, and matrix metalloproteinase (MMP)7 expression level in MDA-MB-231 and Hs578t. Interestingly, immunofluorescence staining showed that siCDH11 reduced β-catenin nuclear localization and attenuated TNBC cell migration, invasion and tumorsphere-formation. Of translational relevance, siCDH11 exhibited significant anticancer efficacy in murine tumor xenograft models, as demonstrated by reduced tumor-size, inhibited tumor growth and longer survival time.

CONCLUSIONS

Our findings indicate that by modulating β-catenin, CDH11 regulates the canonical WNT signalling pathway. CDH11 inhibition suppresses the CSC-like phenotypes and tumor growth of TNBC cells and represents a novel therapeutic approach in TNBC treatment.

The Uncovered Role of Immune Cells and NK Cells in the Regulation of Bone Metastasis

Bone is one of the main metastatic sites of solid tumors like breast, lung, and prostate cancer. Disseminated tumor cells (DTCs) and cancer stem cells (CSCs) represent the main target to counteract bone metastatization. These cells often localize in bone marrow (BM) at level of pre-metastatic niche: they can remain dormant for years or directly grow and create bone lesion, according to the different stimulations received in BM. The immune system in bone marrow is dampened and represents an appealing site for DTCs/CSCs. NK cells have an important role in controlling tumor progression, but their involvement in bone metastasis formation is an interesting and not fully investigated issue. Indeed, whether NK cells can interfere with CSC formation, kill them at the site of primary tumor, during circulation or in the pre-metastic niche needs to be elucidated. This review focuses on different aspects that regulate DTC/CSC life in bone and how NK cells potentially control bone metastasis formation.

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.

Precision therapeutic targeting of human cancer cell motility

Increased cancer cell motility constitutes a root cause of end organ destruction and mortality, but its complex regulation represents a barrier to precision targeting. We use the unique characteristics of small molecules to probe and selectively modulate cell motility. By coupling efficient chemical synthesis routes to multiple upfront in parallel phenotypic screens, we identify that KBU2046 inhibits cell motility and cell invasion in vitro. Across three different murine models of human prostate and breast cancer, KBU2046 inhibits metastasis, decreases bone destruction, and prolongs survival at nanomolar blood concentrations after oral administration. Comprehensive molecular, cellular and systemic-level assays all support a high level of selectivity. KBU2046 binds chaperone heterocomplexes, selectively alters binding of client proteins that regulate motility, and lacks all the hallmarks of classical chaperone inhibitors, including toxicity. We identify a unique cell motility regulatory mechanism and synthesize a targeted therapeutic, providing a platform to pursue studies in humans.

In this study, the authors identify and validate a halogen-substituted isoflavanone able to inhibit prostate cancer cell motility, invasion and metastasis in vitro and in vivo. They demonstrate its ability to selectively inhibit activation of client proteins that stimulate cell motility.

The Biology of Bone Metastasis

Bone metastasis, or the development of secondary tumors within the bone of cancer patients, is a debilitating and incurable disease. Despite its morbidity, the biology of bone metastasis represents one of the most complex and intriguing of all oncogenic processes. This complexity derives from the intricately organized bone microenvironment in which the various stages of hematopoiesis, osteogenesis, and osteolysis are jointly regulated but spatially restricted. Disseminated tumor cells (DTCs) from various common malignancies such as breast, prostate, lung, and kidney cancers or myeloma are uniquely primed to subvert these endogenous bone stromal elements to grow into pathological osteolytic or osteoblastic lesions. This colonization process can be separated into three key steps: seeding, dormancy, and outgrowth. Targeting the processes of dormancy and initial outgrowth offers the most therapeutic promise. Here, we discuss the concepts of the bone metastasis niche, from controlling tumor-cell survival to growth into clinically detectable disease.