Chemokine (C-C motif) ligand 2 mediates the prometastatic effect of dysadherin in human breast cancer cells

Dysadherin expression in prostatic adenocarcinoma and its relationship with E-cadherin and β-catenin

BACKGROUND

We analyzed immunoexpression of Dysadherin, E-cadherin and ß-catenin proteins in prostate.

METHODS

53 radical prostatectomy specimens were included. Dysadherin, E-cadherin and ß-catenin were evaluated in prostatic adenocarcinoma and in adjacent non-tumorous tissue, and correlated with clinicomorphological features in prostatic adenocarcinoma.

RESULTS

We report cytoplasmic/membraneous and nuclear staining for Dysadherin in prostatic tissue. Cytoplasmic/membraneous expression was stronger in prostatic adenocarcinoma when compared to adjacent non-tumorous prostatic tissue (p < 0.001).

Dysadherin positively correlated with T status (rho = 0.326, P = 0.017) and Grade Group (rho = 0.278, P = 0.044). We report no correlation with recurrence, surgical margins status, sPSA and N status. E-cadherin was negatively correlated with recurrence (rho = -0.297, P = 0.031), T status (rho = -0.430, P = 0.001), Grade Group (rho = -0.558, P < 0.001) and positive surgical margins (rho = -0.404, P = 0.003). ß-catenin negatively correlated with Grade Group (rho = -0.557, P < 0,001). No correlation was observed between Dysadherin and E-cadherin and Dysadherin and ß-catenin expression.

CONCLUSION

Our results suggest a potential role for Dysadherin in tumor progression. No significant correlation between Dysadherin and E-cadherin or ß-catenin indicates potential independence of Dysadherin in its regulatory role in prostatic adenocarcinoma.

The dysadherin/MMP9 axis modifies the extracellular matrix to accelerate colorectal cancer progression

The dynamic alteration of the tumor microenvironment (TME) serves as a driving force behind the progression and metastasis of colorectal cancer (CRC). Within the intricate TME, a pivotal player is the extracellular matrix (ECM), where modifications in components, degradation, and stiffness are considered critical factors in tumor development. In this study, we find that the membrane glycoprotein dysadherin directly targets matrix metalloprotease 9 (MMP9), initiating ECM remodeling within the TME and amplifying cancer progression. Mechanistically, the dysadherin/MMP9 axis not only enhances CRC cell invasiveness and ECM proteolytic activity but also activates cancer-associated fibroblasts, orchestrating the restructuring of the ECM through the synthesis of its components in human CRC cells, patient samples, and mouse models. Notably, disruption of ECM reorganization by dysadherin knockout results in a discernible reduction in the immunosuppressive and proangiogenic milieu in a humanized mouse model. Intriguingly, these effects are reversed upon the overexpression of MMP9, highlighting the intricate and pivotal role of the dysadherin/MMP9 axis in shaping the development of a malignant TME. Therefore, our findings not only highlight that dysadherin contributes to CRC progression by influencing the TME through ECM remodeling but also suggest that dysadherin may be a potential therapeutic target for CRC.

The chemokine monocyte chemoattractant protein-1/CCL2 is a promoter of breast cancer metastasis

Breast cancer is the most prevalent cancer worldwide, and metastasis is the leading cause of death in cancer patients. Human monocyte chemoattractant protein-1 (MCP-1/CCL2) was isolated from the culture supernatants of not only mitogen-activated peripheral blood mononuclear leukocytes but also malignant glioma cells based on its in vitro chemotactic activity toward human monocytes. MCP-1 was subsequently found to be identical to a previously described tumor cell-derived chemotactic factor thought to be responsible for the accumulation of tumor-associated macrophages (TAMs), and it became a candidate target of clinical intervention; however, the role of TAMs in cancer development was still controversial at the time of the discovery of MCP-1. The in vivo role of MCP-1 in cancer progression was first evaluated by examining human cancer tissues, including breast cancers. Positive correlations between the level of MCP-1 production in tumors and the degree of TAM infiltration and cancer progression were established. The contribution of MCP-1 to the growth of primary tumors and metastasis to the lung, bone, and brain was examined in mouse breast cancer models. The results of these studies strongly suggested that MCP-1 is a promoter of breast cancer metastasis to the lung and brain but not bone. Potential mechanisms of MCP-1 production in the breast cancer microenvironment have also been reported. In the present manuscript, we review studies in which the role of MCP-1 in breast cancer development and progression and the mechanisms of its production were examined and attempt to draw a consensus and discuss the potential use of MCP-1 as a biomarker for diagnosis.

Thymoquinone Inhibition of Chemokines in TNF-α-Induced Inflammatory and Metastatic Effects in Triple-Negative Breast Cancer Cells

The lack of identifiable molecular targets or biomarkers hinders the development of treatment options in triple-negative breast cancer (TNBC). However, natural products offer a promising alternative by targeting inflammatory chemokines in the tumor microenvironment (TME). Chemokines are crucial in promoting breast cancer growth and metastasis and correlate to the altered inflammatory process. In the present study, we evaluated the anti-inflammatory and antimetastatic effects of the natural product thymoquinone (TQ) on TNF-α-stimulated TNBC cells (MDA-MB-231 and MDA-MB-468) to study the cytotoxic, antiproliferative, anticolony, antimigratory, and antichemokine effects using enzyme-linked immunosorbent assays, quantitative real-time reverse transcription-polymerase chain reactions, and Western blots were used in sequence to validate the microarray results further. Four downregulated inflammatory cytokines were identified, CCL2 and CCL20 in MDA-MB-468 cells and CCL3 and CCL4 in MDA-MB-231 cells. Furthermore, when TNF-α-stimulated MDA-MB-231 cells were compared with MDA-MB-468 cells, the two cells were sensitive to TQ's antichemokine and antimetastatic effect in preventing cell migration. It was concluded from this investigation that genetically different cell lines may respond to TQ differently, as TQ targets CCL3 and CCL4 in MDA-MB-231 cells and CCL2 and CCL20 in MDA-MB-468 cells. Therefore, the results indicate that TQ may be recommended as a component of the therapeutic strategy for TNBC treatment. These outcomes stem from the compound's capacity to suppress the chemokine. Even though these findings support the usage of TQ as part of a therapy strategy for TNBC associated with the identified chemokine dysregulations, additional in vivo studies are needed to confirm these in vitro results.

Transcriptomic Profiling of Breast Cancer Cells Induced by Tumor-Associated Macrophages Generates a Robust Prognostic Gene Signature

Breast cancer, one of the most prevalent neoplasms in the world, continues attracting worldwide attention. Macrophage, as the most abundant non-malignant cell in tumor, plays critical roles in both immune surveillance and tumorigenesis and has become a cell target of immunotherapy. Among all macrophages, tumor-associated macrophage (TAM) is regarded as the main force to promote tumorigenesis. To get an overall view of its impact on breast cancer, we employed a simplified and indirect coculturing cell model followed by RNA-sequencing to detect cancer cell's transcriptomic response induced by TAM and a prognostic gene signature was constructed based on it. Evidence from both cell models and clinical samples strengthened TAM's full-dimensional impact on breast cancer, involved in almost all known signal pathways dysregulated during tumorigenesis from transcription, translation and molecule transport to immune-related pathways. Consequently, the gene signature developed from these genes was tested to be powerful in prognostic prediction and associated with various clinical and biological features of breast cancer. Our study presented a more complete view of TAM's impact on breast cancer, which strengthened its role as an important therapy target. A 45-gene signature from the TAM-regulated genes was developed and shown potential in clinical application.

Prognostic value of dysadherin in cancer: A systematic review and meta-analysis

Cancer is a leading cause of death worldwide and novel prognostic factors are reported with increasing numbers. Systematic reviews and meta-analyses on cumulative research data are crucial in estimating the true prognostic value of proposed factors. Dysadherin (FXYD Domain Containing Ion Transport Regulator 5; FXYD5) is a cell membrane glycoprotein that modulates Na+, K+-ATPase activity and cell-cell adhesion. It is abundantly expressed in a variety of cancer cells, but only in a limited number of normal cells and its levels are increased in many different tumor types. The expression or level of dysadherin has been suggested as an independent predictor for metastasis and poor prognosis by number of studies, yet we lack a definitive answer. In this study, we systematically evaluated the prognostic value of dysadherin in cancer and summarized the current knowledge on the subject. PubMed, Scopus, Web of Science and relevant clinical trial and preprint databases were searched for relevant publications and PRISMA and REMARK guidelines were applied in the process. After a careful review, a total of 23 original research articles were included. In each study, dysadherin was pointed as a marker for poor prognosis. Meta-analyses revealed 3- and 1.5-fold increases in the risk of death (fixed effects HR 3.08, 95% CI 1.88-5.06, RR 1.47, 95% CI 1.06-2.05 on overall survival, respectively) for patients with high (>50%) tumoral FXYD5 level. In many studies, a connection between dysadherin expression or level and metastatic behavior of the cancer as well as inverse correlation with E-cadherin level were reported. Thus, we conclude that dysadherin might be a useful prognostic biomarker in the assessment of disease survival of patients with solid tumors.

Alteration in Plasma Metabolome in High-Fat Diet-Fed Monocyte Chemotactic Protein-1 Knockout Mice Bearing Pulmonary Metastases of Lewis Lung Carcinoma

Both clinical and laboratory studies have shown that monocyte chemotactic protein-1 (MCP-1) is involved in cancer spread. To understand the role of MCP-1 in metabolism in the presence of metastasis, we conducted an untargeted metabolomic analysis of primary metabolism on plasma collected from a study showing that MCP-1 deficiency reduces spontaneous metastasis of Lewis lung carcinoma (LLC) to the lungs in mice fed a high-fat diet (HFD). In a 2 × 2 design, wild-type (WT) or Mcp-1 knockout (Mcp-1 -/-) mice maintained on the AIN93G standard diet or HFD were subcutaneously injected with LLC cells to induce lung metastasis. We identified 87 metabolites for metabolomic analysis from this study. Amino acid metabolism was altered considerably in the presence of LLC metastases with the aminoacyl-tRNA biosynthesis pathways as the leading pathway altered. The HFD modified lipid and energy metabolism, evidenced by lower contents of arachidonic acid, cholesterol, and long-chain saturated fatty acids and higher contents of glucose and pyruvic acid in mice fed the HFD. These findings were supported by network analysis showing alterations in fatty acid synthesis and glycolysis/gluconeogenesis pathways between the 2 diets. Furthermore, elevations of the citrate cycle intermediates (citric acid, fumaric acid, isocitric acid, and succinic acid) and glyceric acid in Mcp-1 -/- mice, regardless of diet, suggest the involvement of MCP-1 in mitochondrial energy metabolism during LLC metastasis. The present study demonstrates that MCP-1 deficiency and the HFD altered plasma metabolome in mice bearing LLC metastases. These findings can be useful in understanding the impact of obesity on prevention and treatment of cancer metastasis.

Sanguinarine Inhibition of TNF-α-Induced CCL2, IKBKE/NF-κB/ERK1/2 Signaling Pathway, and Cell Migration in Human Triple-Negative Breast Cancer Cells

Angiogenesis is a process that drives breast cancer (BC) progression and metastasis, which is linked to the altered inflammatory process, particularly in triple-negative breast cancer (TNBC). In targeting inflammatory angiogenesis, natural compounds are a promising option for managing BC. Thus, this study was designed to determine the natural alkaloid sanguinarine (SANG) potential for its antiangiogenic and antimetastatic properties in triple-negative breast cancer (TNBC) cells. The cytotoxic effect of SANG was examined in MDA-MB-231 and MDA-MB-468 cell models at a low molecular level. In this study, SANG remarkably inhibited the inflammatory mediator chemokine CCL2 in MDA-MB-231 and MDA-MB-468 cells. Furthermore, qRT-PCR confirmed with Western analysis studies showed that mRNA CCL2 repression was concurrent with reducing its main regulator IKBKE and NF-κB signaling pathway proteins in both TNBC cell lines. The total ERK1/2 protein was inhibited in the more responsive MDA-MB-231 cells. SANG exhibited a higher potential to inhibit cell migration in MDA-MB-231 cells compared to MDA-MB-468 cells. Data obtained in this study suggest a unique antiangiogenic and antimetastatic effect of SANG in the MDA-MB-231 cell model. These effects are related to the compound’s ability to inhibit the angiogenic CCL2 and impact the ERK1/2 pathway. Therefore, SANG use may be recommended as a component of the therapeutic strategy for TNBC.

Fxyd5 activates the NF‑κB pathway and is involved in chondrocytes inflammation and extracellular matrix degradation

It is known that increased inflammation and extracellular matrix (ECM) degradation in chondrocytes can promote the development of osteoarthritis (OA). The FXYD domain containing ion transport regulator 5 (Fxyd5) has been found to promote chronic inflammatory responses. The present study aimed to investigate the role of Fxyd5 in OA. Murine ATDC5 chondrocytes were transfected with short hairpin RNAs specifically targeting Fxyd5 to silence its expression. Subsequently, cells were induced with lipopolysaccharide (LPS). The protein expression levels of Fxyd5, MMPs and proteins related to ECM, apoptosis and NF-κB signaling were detected using western blot analysis. In addition, cell viability was assessed using a Cell Counting Kit-8 assay, while the secretion of the proinflammatory factors and those of the oxidative stress-related markers were measured using the corresponding kits. Finally, cells were treated with the NF-κB activator, betulinic acid (BA) and the above experiments were repeated. The results demonstrated that Fxyd5 was significantly upregulated in ATDC5 cells treated with LPS. Additionally, Fxyd5 knockdown increased cell viability, enhanced the protein expression of Bcl-2, Aggrecan and collagen II, while reduced the expression of Bax, cleaved caspase-3/caspase-3, MMP3 and MMP13 in LPS-induced ATDC5 cells. The production of IL-1β, IL-6 and IL-18 as well as reactive oxygen species and malondialdehyde, and the reduction of superoxide dismutase caused by LPS in ATDC5 cells, were also reversed by Fxyd5 silencing. Fxyd5 silencing inhibited the phosphorylation of p65 and IκBα induced by LPS. Finally, BA reversed the protective effect of Fxyd5 silencing on LPS induced chondrocytes injury. In conclusion, Fxyd5 could enhance chondrocyte inflammation and ECM degradation via activating the NF-κB signaling.

Cancer-Associated Fibroblasts in Breast Cancer Treatment Response and Metastasis

Breast cancer (BrCa) is the leading cause of death among women worldwide, with about one million new cases diagnosed each year. In spite of the improvements in diagnosis, early detection and treatment, there is still a high incidence of mortality and failure to respond to current therapies. With the use of several well-established biomarkers, such as hormone receptors and human epidermal growth factor receptor-2 (HER2), as well as genetic analysis, BrCa patients can be categorized into multiple subgroups: Luminal A, Luminal B, HER2-enriched, and Basal-like, with specific treatment strategies. Although chemotherapy and targeted therapies have greatly improved the survival of patients with BrCa, there is still a large number of patients who relapse or who fail to respond. The role of the tumor microenvironment in BrCa progression is becoming increasingly understood. Cancer-associated fibroblasts (CAFs) are the principal population of stromal cells in breast tumors. In this review, we discuss the current understanding of CAFs' role in altering the tumor response to therapeutic agents as well as in fostering metastasis in BrCa. In addition, we also review the available CAFs-directed molecular therapies and their potential implications for BrCa management.

Reduced IQGAP2 expression promotes EMT and inhibits apoptosis by modulating the MEK-ERK and p38 signaling in breast cancer irrespective of ER status

IQGAP2, a member of the IQGAP family, functions as a tumor suppressor in most of the cancers. Unlike IQGAP1 and IQGAP3, which function as oncogenes in breast cancer, the role of IQGAP2 is still unexplored. Here we report a reduced expression of IQGAP2, which was associated with lymph node positivity, lymphovascular invasion, and higher age in breast cancer patients. We found an inverse correlation of IQGAP2 expression levels with oncogenic properties of breast cancer cell lines in estrogen receptor (ER) independent manner. IQGAP2 expression enhanced apoptosis via reactive oxygen species (ROS)-P38-p53 pathway and reduced epithelial-mesenchymal transition (EMT) in a MEK-ERK-dependent manner. IQGAP2-IQGAP1 ratio correlated negatively with phospho-ERK levels in breast cancer patients. Pull-down assay showed interaction of IQGAP1 and IQGAP2. IQGAP2 overexpression rescued, IQGAP1-mediated ERK activation, suggesting the possibility of IQGAP1 sequestration by IQGAP2. IQGAP2 depletion, in a tumor xenograft model, increased tumor volume, tumor weight, and phospho-ERK expression. Overall, our findings suggest that IQGAP2 is negatively associated with proliferative and metastatic abilities of breast cancer cells. Suppression of IQGAP1-mediated ERK activation is a possible route via which IQGAP2 restricts oncogenic properties of breast cancer cells. Our study highlights the candidature of IQGAP2 as a potent target for therapeutic intervention.

Molecular mechanism of gossypol mediating CCL2 and IL‑8 attenuation in triple‑negative breast cancer cells

Chronic inflammation associated with cancer is characterized by the production of different types of chemokines and cytokines. In cancer, numerous signaling pathways upregulate the expression levels of several cytokines and evolve cells to the neoplastic state. Therefore, targeting these signaling pathways through the inhibition of distinctive gene expression is a primary target for cancer therapy. The present study investigated the anticancer effects of the natural polyphenol gossypol (GOSS) in triple-negative breast cancer (TNBC) cells, the most aggressive breast cancer type with poor prognosis. GOSS effects were examined in two TNBC cell lines: MDA-MB-231 (MM-231) and MDA-MB-468 (MM-468), representing Caucasian Americans (CA) and African Americans (AA), respectively. The obtained IC₅₀s revealed no significant difference between the two cell lines' response to the compound. However, the use of microarray assays for cytokine determination indicated the ability of GOSS to attenuate the expression levels of cancer-related cytokines in the two cell lines. Although GOSS did not alter CCL2 expression in MM-468 cells, it was able to cause 30% inhibition in TNF-α-stimulated MM-231 cells. Additionally, IL-8 was not altered by GOSS treatment in MM-231 cells, while its expression was inhibited by 60% in TNF-α-activated MM-468 cells. ELISA assays supported the microarray data and indicated that CCL2 expression was inhibited by 40% in MM-231 cells, and IL-8 expression was inhibited by 50% in MM-468 cells. Furthermore, in MM-231 cells, GOSS inhibited CCL2 release via the repression of IKBKE, CCL2 and MAPK1 gene expression. Additionally, in MM-468 cells, the compound downregulated the release of IL-8 through repressing IL-8, MAPK1, MAPK3, CCDC88A, STAT3 and PIK3CD gene expression. In conclusion, the data obtained in the present study indicate that the polyphenol compound GOSS may provide a valuable tool in TNBC therapy.

Evaluation of the Effect of Foeniculum vulgare on the Expression of E-Cadherin, Dysadherin and Ki-67 in BALB/C Mice with 4T1 Model of Breast Cancer

Introduction: Breast cancer is described as a serious disease and one of the important factors of cancer-related deaths. Considering the drug resistance, special attention has been paid to natural compounds. This study aimed at evaluating the anti-metastatic activity of fennel in a breast cancer mouse model.Methods: A total of 28 adult female BALB/C mice were used in this study. Breast cancer was induced by subcutaneous injection of 4T1 cells in the right lower flank. The mice received fennel extracts daily via intraperitoneal injection for two weeks. Meanwhile, tumor volume was measured every day using calipers. After two weeks, each animal was anesthetized. The expression levels of ki-67 and dysadherin as tumor markers, as well as E-cadherin as a tumor suppressor, were measured in tumor tissue and ovary. Also the expression of her2 was measured in ovary.Results: Tumor size significantly decreased after nine days treatment of the fennel. Fennel treatment caused an increase in the ratio of the expression of E-cadherin to Ki-67 and dysadherin in the tumor tissues. On the other hand, the expression of Ki-67 and HER2 decreased in the ovary.Conclusion: Based on our findings, fennel has anti-tumor and anti-metastatic activities against aggressive cancers.

Dietary Selenium Supplementation Does Not Attenuate Mammary Tumorigenesis-Mediated Bone Loss in Male MMTV-PyMT Mice

Bone wasting occurs during the progression of breast cancer and contributes to breast cancer mortality. We evaluated the effect of methylseleninic acid (MSeA), an anti-carcinogenic form of selenium, on bone microstructural changes in the presence of mammary tumors in a male breast cancer model of mouse mammary tumor virus-polyomavirus middle T-antigen (MMTV-PyMT). In this study, we performed microcomputed tomographic analysis of femurs and vertebrae collected from a study showing that dietary supplementation with MSeA reduces mammary tumorigenesis in male mice. Compared to age-matched, non-tumor-bearing mice (MMTV-PyMT negative), the presence of mammary tumors significantly reduced the bone volume fraction, trabecular thickness, and bone mineral density while it increased the structure model index in femurs, but not in vertebrae. Moreover, mammary tumorigenesis decreased plasma concentrations of osteocalcin. Supplementation with MSeA did not affect these changes in MMTV-PyMT mice. In conclusion, mammary tumorigenesis caused bone loss in MMTV-PyMT mice. However, dietary supplementation with MSeA did not attenuate mammary tumor-associated bone loss in this model of male breast cancer.

Characterization of Glyceollins as Novel Aryl Hydrocarbon Receptor Ligands and Their Role in Cell Migration

Recent studies strongly support the use of the aryl hydrocarbon receptor (AhR) as a therapeutic target in breast cancer. Glyceollins, a group of soybean phytoalexins, are known to exert therapeutic effects in chronic human diseases and also in cancer. To investigate the interaction between glyceollin I (GI), glyceollin II (GII) and AhR, a computational docking analysis, luciferase assays, immunofluorescence and transcriptome analyses were performed with different cancer cell lines. The docking experiments predicted that GI and GII can enter into the AhR binding pocket, but their interactions with the amino acids of the binding site differ, in part, from those interacting with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Both GI and GII were able to weakly and partially activate AhR, with GII being more potent. The results from the transcriptome assays showed that approximately 10% of the genes regulated by TCDD were also modified by both GI and GII, which could have either antagonistic or synergistic effects upon TCDD activation. In addition, we report here, on the basis of phenotype, that GI and GII inhibit the migration of triple-negative (ER-, PgR-, HER2NEU-) MDA-MB-231 breast cancer cells, and that they inhibit the expression of genes which code for important regulators of cell migration and invasion in cancer tissues. In conclusion, GI and GII are AhR ligands that should be further investigated to determine their usefulness in cancer treatments.

FXYD5/Dysadherin, a Biomarker of Endometrial Cancer Myometrial Invasion and Aggressiveness: Its Relationship With TGF-β1 and NF-κB Pathways

Objective: Endometrial cancer (EC) is the second most common gynecological cancer worldwide. Myometrial invasion (MI) is a key event in EC dissemination. This study aimed to evaluate FXYD5/dysadherin (FXYD5/Dys) expression in EC tissue and uterine aspirate (UA) biopsies and to assess molecular/functional changes associated with its expression in cellular models. Methods: FXYD5/Dys messenger RNA (mRNA) levels were determined in EC tissue and UA biopsies. FXYD5/Dys expression was evaluated in EC RNAseq data from The Cancer Genome Atlas (TCGA) and GENEVESTIGATOR tools. FXYD5/Dys impact on E-cadherin expression and cell behavior was assessed in EC Hec1a cells treated with transforming growth factor (TGF)-β1, stably transfected with ETV5, and transiently transfected with FXYD5/Dys small interfering RNA (siRNA) or pcDNA3-FXYD5/Dys plasmid. Results: FXYD5/Dys was associated with EC aggressiveness, finding high mRNA levels in tumors depicting MI > 50%, Grade 3, and intermediate/high risk of recurrence. FXYD5/Dys was highly expressed at the tumor invasive front compared to the superficial area. Most results were recapitulated in UA biopsies. FXYD5/Dys modulation in Hec1a cells altered cell migration/adhesion and E-cadherin expression. TGF-β1 treatment of Hec1a cells induced FXYD5/Dys expression. TCGA-UCEC RNAseq analysis revealed a positive correlation between FXYD5/Dys, TGF-β1, and plasminogen activator inhibitor (PAI)-1 mRNA levels. FXYD5/Dys induced nuclear factor (NF)-κB pathway activation in Hec1a cells. FXYD5/Dys mRNA levels positively correlated with transcriptional activation of NF-κB p65-regulated genes. Survival analysis revealed patient segregation into low- and high-risk groups, the latter depicting the highest FXYD5/Dys, PAI-1, tumor necrosis factor (TNF)-α, and TGF-β1 mRNA levels and shorter survival rates. Conclusion: FXYD5/Dys is a novel biomarker of EC progression related to TGF-β1 and NF-κB pathways that collectively promote tumor dissemination and result in poor patient prognosis.

A FXYD5/TGF‑β/SMAD positive feedback loop drives epithelial‑to‑mesenchymal transition and promotes tumor growth and metastasis in ovarian cancer

Epithelial ovarian cancer is aggressive and lacks effective prognostic indicators or therapeutic targets. In the present study, using immunohistochemistry and bioinformatics analysis on ovarian cancer tissue data from The Obstetrics and Gynecology Hospital of Fudan University and The Cancer Genome Atlas database, it was identified that FXYD domain‑containing ion transport regulator 5 (FXYD5) expression was upregulated in the SKOV3‑IP cell line compared with its parental cell line, SKOV3, and in ovarian cancer tissues compared with in normal tissues. In addition, FXYD5 upregulation was predictive of poor patient survival. Furthermore, through various in vitro (Transwell assay, clonogenic assay and western blot analysis) and in vivo (nude mouse model) experiments, it was demonstrated that FXYD5 promoted the metastasis of ovarian cancer cells. Mechanistically, RNA sequencing, western blot analysis, a luciferase reporter assay and chromatin immunoprecipitation were performed to reveal that FXYD5 dispersed the SMAD7‑SMAD specific E3 ubiquitin protein ligase 2‑TGF‑β receptor 1 (TβR1) complex, deubiquitinated and stabilized TβR1, and subsequently enhanced transforming growth factor‑β (TGF‑β) signaling and sustained TGF‑β‑driven epithelial‑mesenchymal transition (EMT). The TGF‑β‑activated SMAD3/SMAD4 complex was in turn directly recruited to the FXYD5 promoter region, interacted with specific SMAD‑binding elements, and then promoted FXYD5 transcription. In brief, FXYD5 positively regulated TGF‑β/SMADs signaling activities, which in turn induced FXYD5 expression, creating a positive feedback loop to drive EMT in the process of ovarian cancer progression. Collectively, the findings of the present study suggested a mechanism through which FXYD5 serves a critical role in the constitutive activation of the TGF‑β/SMADs signaling pathways in ovarian cancer, and provided a promising therapeutic target for human ovarian cancer.

FXYD5 (Dysadherin) upregulation predicts shorter survival and reveals platinum resistance in high-grade serous ovarian cancer patients

BACKGROUND

High-grade serous ovarian carcinoma (HGSOC) is generally associated with a very dismal prognosis. Nevertheless, patients with similar clinicopathological characteristics can have markedly different clinical outcomes. Our aim was the identification of novel molecular determinants influencing survival.

METHODS

Gene expression profiles of extreme HGSOC survivors (training set) were obtained by microarray. Differentially expressed genes (DEGs) and enriched signalling pathways were determined. A prognostic signature was generated and validated on curatedOvarianData database through a meta-analysis approach. The best prognostic biomarker from the signature was confirmed by RT-qPCR and by immunohistochemistry on an independent validation set. Cox regression model was chosen for survival analysis.

RESULTS

Eighty DEGs and the extracellular matrix-receptor (ECM-receptor) interaction pathway were associated to extreme survival. A 10-gene prognostic signature able to correctly classify patients with 98% of accuracy was identified. By an 'in-silico' meta-analysis, overexpression of FXYD domain-containing ion transport regulator 5 (FXYD5), also known as dysadherin, was confirmed in HGSOC short-term survivors compared to long-term ones. Its prognostic and predictive power was then successfully validated, both at mRNA and protein level, first on training than on validation sample set.

CONCLUSION

We demonstrated the possible involvement of FXYD5 and ECM-receptor interaction signal pathway in HCSOC survival and prognosis.

Tumor-Stroma-Inflammation Networks Promote Pro-metastatic Chemokines and Aggressiveness Characteristics in Triple-Negative Breast Cancer

The tumor microenvironment (TME) plays key roles in promoting disease progression in the aggressive triple-negative subtype of breast cancer (TNBC; Basal/Basal-like). Here, we took an integrative approach and determined the impact of tumor-stroma-inflammation networks on pro-metastatic phenotypes in TNBC. With the TCGA dataset we found that the pro-inflammatory cytokines tumor necrosis factor α (TNFα) and interleukin 1β (IL-1β), as well as their target pro-metastatic chemokines CXCL8 (IL-8), CCL2 (MCP-1), and CCL5 (RANTES) were expressed at significantly higher levels in basal patients than luminal-A patients. Then, we found that TNFα- or IL-1β-stimulated co-cultures of TNBC cells (MDA-MB-231, MDA-MB-468, BT-549) with mesenchymal stem cells (MSCs) expressed significantly higher levels of CXCL8 compared to non-stimulated co-cultures or each cell type alone, with or without cytokine stimulation. CXCL8 was also up-regulated in TNBC co-cultures with breast cancer-associated fibroblasts (CAFs) derived from patients. CCL2 and CCL5 also reached the highest expression levels in TNFα/IL-1β-stimulated TNBC:MSC/CAF co-cultures. The elevations in CXCL8 and CCL2 expression partly depended on direct physical contacts between the tumor cells and the MSCs/CAFs, whereas CCL5 up-regulation was entirely dependent on cell-to-cell contacts. Supernatants of TNFα-stimulated TNBC:MSC "Contact" co-cultures induced robust endothelial cell migration and sprouting. TNBC cells co-cultured with MSCs and TNFα gained migration-related morphology and potent migratory properties; they also became more invasive when co-cultured with MSCs/CAFs in the presence of TNFα. Using siRNA to CXCL8, we found that CXCL8 was significantly involved in mediating the pro-metastatic activities gained by TNFα-stimulated TNBC:MSC "Contact" co-cultures: angiogenesis, migration-related morphology of the tumor cells, as well as cancer cell migration and invasion. Importantly, TNFα stimulation of TNBC:MSC "Contact" co-cultures in vitro has increased the aggressiveness of the tumor cells in vivo, leading to higher incidence of mice with lung metastases than non-stimulated TNBC:MSC co-cultures. Similar tumor-stromal-inflammation networks established in-culture with luminal-A cells demonstrated less effective or differently-active pro-metastatic functions than those of TNBC cells. Overall, our studies identify novel tumor-stroma-inflammation networks that may promote TNBC aggressiveness by increasing the pro-malignancy potential of the TME and of the tumor cells themselves, and reveal key roles for CXCL8 in mediating these metastasis-promoting activities.

SERPINB2 Is a Novel Indicator of Cancer Stem Cell Tumorigenicity in Multiple Cancer Types

Drug resistance is one of the major characteristics of cancer stem cells (CSCs) and a mechanism of tumor recurrence. Therefore, selectively targeting CSCs may be an effective therapeutic strategy to overcome cancer recurrence. In the present study, we found that exposure to tumorigenic compounds significantly increased the growth potential and stem-cell-like properties of various CSCs. Early-response genes involved in tumorigenesis can be used as specific markers to predict potential tumorigenicity. Importantly, for the first time we identified, a labile tumorigenic response gene—SERPINB2—and showed that tumorigenic compound exposure more profoundly affected its expression in CSCs than in non-stem cancer cells, although both cells exhibit basal expression of SERPINB2 in multiple cancer types. Our data also revealed a strong relationship between the significantly enhanced expression of SERPINB2 and metastatic progression in multiple cancer types. To the best of our knowledge, this is the first study to focus on the functions of SERPINB2 in the tumorigenicity of various CSCs and these findings will facilitate the development of promising tumorigenicity test platforms.

A strategy for generating cancer-specific monoclonal antibodies to aberrant O-glycoproteins: identification of a novel dysadherin-Tn antibody

Successful application of potent antibody-based T-cell engaging immunotherapeutic strategies is currently limited mainly to hematological cancers. One major reason is the lack of well-characterized antigens on solid tumors with sufficient cancer specific expression. Aberrantly O-glycosylated proteins contain promising cancer-specific O-glycopeptide epitopes suitable for immunotherapeutic applications, but currently only few examples of such antibody epitopes have been identified. We previously showed that chimeric antigen receptor T-cells directed towards aberrantly O-glycosylated MUC1 can control malignant growth in a mouse model. Here, we present a discovery platform for the generation of cancer-specific monoclonal antibodies targeting aberrant O-glycoproteins. The strategy is based on cancer cell lines engineered to homogeneously express the truncated Tn O-glycoform, the so-called SimpleCells. We used SimpleCells of different cancer origin to elicit monoclonal antibodies with selectivity for aberrant O-glycoproteins. For validation we selected and characterized one monoclonal antibody (6C5) directed to a Tn-glycopeptide in dysadherin (FXYD5), known to be upregulated in cancer and promote metastasis. While dysadherin is widely expressed also in normal cells, we demonstrated that the 6C5 epitope is specifically expressed in cancer.

LNMAT1 promotes lymphatic metastasis of bladder cancer via CCL2 dependent macrophage recruitment

Tumor-associated macrophages (TAMs) are the most abundant inflammatory infiltrates in the tumor microenvironment and contribute to lymph node (LN) metastasis. However, the precise mechanisms of TAMs-induced LN metastasis remain largely unknown. Herein, we identify a long noncoding RNA, termed Lymph Node Metastasis Associated Transcript 1 (LNMAT1), which is upregulated in LN-positive bladder cancer and associated with LN metastasis and prognosis. Through gain and loss of function approaches, we find that LNMAT1 promotes bladder cancer-associated lymphangiogenesis and lymphatic metastasis. Mechanistically, LNMAT1 epigenetically activates CCL2 expression by recruiting hnRNPL to CCL2 promoter, which leads to increased H3K4 tri-methylation that ensures hnRNPL binding and enhances transcription. Furthermore, LNMAT1-induced upregulation of CCL2 recruits macrophages into the tumor, which promotes lymphatic metastasis via VEGF-C excretion. These findings provide a plausible mechanism for LNMAT1-modulated tumor microenvironment in lymphatic metastasis and suggest that LNMAT1 may represent a potential therapeutic target for clinical intervention in LN-metastatic bladder cancer.

The inhibitory effects of plumbagin on the NF-қB pathway and CCL2 release in racially different triple-negative breast cancer cells

Breast cancer (BC) is the second leading cause of death among women in the US, and its subtype triple-negative BC (TNBC) is the most aggressive BC with poor prognosis. In the current study, we investigated the anticancer effects of the natural product plumbagin (PL) on racially different TNBC cells. The PL effects were examined in two TNBC cell lines: MDA-MB-231 (MM-231) and MDA-MB-468 (MM-468), representing Caucasian Americans and African Americans, respectively. The results obtained indicate that PL inhibited cell viability and cell proliferation and induced apoptosis in both cell lines. Notably, MM-468 cells were 5-fold more sensitive to PL than MM-231 cells were. Testing PL and Taxol® showed the superiority of PL over Taxol® as an antiproliferative agent in MM-468 cells. PL treatment resulted in an approximately 20-fold increase in caspase-3 activity with 3 μM PL in MM-468 cells compared with an approximately 3-fold activity increase in MM-231 cells with 8 μM PL. Moreover, the results indicate a higher sensitivity to PL in MM-468 cells than in MM-231 cells. The results also show that PL downregulated CCL2 cytokine expression in MM-468 cells by 30% compared to a 90% downregulation in MM-231 cells. The ELISA results confirmed the array data (35% vs. 75% downregulation in MM-468 and MM-231 cells, respectively). Moreover, PL significantly downregulated IL-6 and GM-CSF in the MM-231 cells. Indeed, PL repressed many NF-қB-regulated genes involved in the regulation of apoptosis, proliferation, invasion, and metastasis. The compound significantly downregulated the same genes (BIRC3, CCL2, TLR2, and TNF) in both types of cells. However, PL impacted five more genes in MM-231 cells, including BCL2A1, ICAM1, IKBKE, IL1β, and LTA. In conclusion, the data obtained in this study indicate that the quinone compound PL could be a novel cancer treatment for TNBC in African American women.

Dysadherin specific drug conjugates for the treatment of thyroid cancers with aggressive phenotypes

Background

EDC1 is a novel type of antibody-drug conjugate which binds and inhibits the Na,K-ATPase on the surface of cancer cells expressing dysadherin. The purpose of this study was to determine the expression of dysadherin in different types of thyroid carcinoma, and evaluate the therapeutic potential of EDC1 for thyroid carcinomas.

Methods

Thyroid tissues from 158 patients were examined for dysadherin expression and correlation with clinicopathological features. Thyroid cancer cell lines were examined for the expression of dysadherin and effective dose range of EDC1.

RESULTS

One in 53 benign thyroid tissues and 62% of thyroid cancers expressed dysadherin. All anaplastic and a majority of papillary thyroid cancers overexpressed dysadherin, while 25% of follicular thyroid cancers was found to be positive for dysadherin. Dysadherin expression significantly correlated with extrathyroidal extension and lymph node metastases in papillary thyroid cancer. Five of six human thyroid cancer cell lines analyzed expressed high levels of dysadherin. Of those cells lines sensitive to EDC1, half maximal effective concentrations (EC50) were observed to be between 0.125 nM and 1 nM.

Conclusions

EDC1 showed selective inhibition of growth in thyroid cancer cells with moderate to high expression of dysadherin, thus could be a specific and effective treatment.

Novel metastatic models of esophageal adenocarcinoma derived from FLO-1 cells highlight the importance of E-cadherin in cancer metastasis

There is currently a paucity of preclinical models available to study the metastatic process in esophageal cancer. Here we report FLO-1, and its isogenic derivative FLO-1LM, as two spontaneously metastatic cell line models of human esophageal adenocarcinoma. We show that FLO-1 has undergone epithelial-mesenchymal transition and metastasizes following subcutaneous injection in mice. FLO-1LM, derived from a FLO-1 liver metastasis, has markedly enhanced proliferative, clonogenic, anti-apoptotic, invasive, immune-tolerant and metastatic potential. Genome-wide RNAseq profiling revealed a significant enrichment of metastasis-related pathways in FLO-1LM cells. Moreover, CDH1, which encodes the adhesion molecule E-cadherin, was the most significantly downregulated gene in FLO-1LM compared to FLO-1. Consistent with this, repression of E-cadherin expression in FLO-1 cells resulted in increased metastatic activity. Importantly, reduced E-cadherin expression is commonly reported in esophageal adenocarcinoma and independently predicts poor patient survival. Collectively, these findings highlight the biological importance of E-cadherin activity in the pathogenesis of metastatic esophageal adenocarcinoma and validate the utility of FLO-1 parental and FLO-1LM cells as preclinical models of metastasis in this disease.

The chemokine MCP-1 (CCL2) in the host interaction with cancer: a foe or ally?

Macrophages are one of the most abundant leukocyte populations infiltrating tumor tissues and can exhibit both tumoricidal and tumor-promoting activities. In 1989, we reported the purification of monocyte chemoattractant protein-1 (MCP-1) from culture supernatants of mitogen-activated peripheral blood mononuclear cells and tumor cells. MCP-1 is a potent monocyte-attracting chemokine, identical to the previously described lymphocyte-derived chemotactic factor or tumor-derived chemotactic factor, and greatly contributes to the recruitment of blood monocytes into sites of inflammatory responses and tumors. Because in vitro-cultured tumor cells often produce significant amounts of MCP-1, tumor cells are considered to be the main source of MCP-1. However, various non-tumor cells in the tumor stroma also produce MCP-1 in response to stimuli. Studies performed in vitro and in vivo have provided evidence that MCP-1 production in tumors is a consequence of complex interactions between tumor cells and non-tumor cells and that both tumor cells and non-tumor cells contribute to the production of MCP-1. Although MCP-1 production was once considered to be a part of host defense against tumors, it is now believed to regulate the vicious cycle between tumor cells and macrophages that promotes the progression of tumors.

HIF2α/EFEMP1 cascade mediates hypoxic effects on breast cancer stem cell hierarchy

Breast cancer stem cells (BCSCs) have been shown to contribute to tumor growth, metastasis, and recurrence. They are also markedly resistant to conventional cancer treatments, such as chemotherapy and radiation. Recent studies have suggested that hypoxia is one of the prominent micro-environmental factors that increase the self-renewal ability of BCSCs, partially by enhancing CSC phenotypes. Thus, the identification and development of new therapeutic approaches based on targeting the hypoxia-dependent responses in BCSCs is urgent. Through various in vitro studies, we found that hypoxia specifically up-regulates BCSC sphere formation and a subset of CD44+/CD24-/low CSCs. Hypoxia inducible factors 2α (HIF2α) depletion suppressed CSC-like phenotypes and CSC-mediated drug resistance in breast cancer. Furthermore, the stimulatory effects of hypoxia-induced HIF2α on BCSC sphere formation were successfully attenuated by epidermal growth factor-containing fibulin-like extracellular matrix protein 1 (EFEMP1) knockdown. Taken together, these data suggest that HIF2α mediates hypoxia-induced cancer growth/metastasis and that EFEMP1 is a downstream effector of hypoxia-induced HIF2α during breast tumorigenesis.

Monocyte chemotactic protein-1 deficiency reduces spontaneous metastasis of Lewis lung carcinoma in mice fed a high-fat diet

Adipose-produced pro-inflammatory cytokines contribute to obesity and cancer. This 2×2 experiment was designed to investigate effects of monocyte chemotactic protein-1 (MCP-1) deficiency on pulmonary metastasis of Lewis lung carcinoma (LLC) in MCP-1 deficient and wild-type mice fed a modified AIN93G diet containing 16% and 45% of energy from corn oil, respectively. The high-fat diet significantly increased the number and size (cross-sectional area and volume) of lung metastases compared to the AIN93G control diet. Deficiency in MCP-1 reduced lung metastases by 37% in high-fat diet-fed mice; it reduced metastatic cross-sectional area by 46% and volume by 69% compared to wild-type mice. Adipose and plasma concentrations of MCP-1 were significantly higher in high-fat diet-fed wild-type mice than in their AIN93G-fed counterparts; they were not detectable in MCP-1 deficient mice regardless of diet. Plasma concentrations of plasminogen activator inhibitor-1, tumor necrosis factor-α, vascular endothelial growth factor and tissue inhibitor of metalloproteinase-1 were significantly higher in MCP-1 deficient mice compared to wild-type mice. We conclude that adipose-produced MCP-1 contributes to high-fat diet-enhanced metastasis. While MCP-1 deficiency reduces metastasis, the elevation of pro-inflammatory cytokines and angiogenic factors in the absence of MCP-1 may support the metastatic development and growth of LLC in MCP-1 deficient mice.

Monocyte chemotactic protein-1 deficiency attenuates and high-fat diet exacerbates bone loss in mice with Lewis lung carcinoma

Bone loss occurs in obesity and cancer-associated complications including wasting. This study determined whether a high-fat diet and a deficiency in monocyte chemotactic protein-1 (MCP-1) altered bone structural defects in male C57BL/6 mice with Lewis lung carcinoma (LLC) metastases in lungs. Compared to non-tumor-bearing mice, LLC reduced bone volume fraction, connectivity density, trabecular number, trabecular thickness and bone mineral density and increased trabecular separation in femurs. Similar changes occurred in vertebrae. The high-fat diet compared to the AIN93G diet exacerbated LLC-induced detrimental structural changes; the exacerbation was greater in femurs than in vertebrae. Mice deficient in MCP-1 compared to wild-type mice exhibited increases in bone volume fraction, connectivity density, trabecular number and decreases in trabecular separation in both femurs and vertebrae, and increases in trabecular thickness and bone mineral density and a decrease in structure model index in vertebrae. Lewis lung carcinoma significantly decreased osteocalcin but increased tartrate-resistant acid phosphatase 5b (TRAP 5b) in plasma. In LLC-bearing mice, the high-fat diet increased and MCP-1 deficiency decreased plasma TRAP 5b; neither the high-fat diet nor MCP-1 deficiency resulted in significant changes in plasma concentration of osteocalcin. In conclusion, pulmonary metastasis of LLC is accompanied by detrimental bone structural changes; MCP-1 deficiency attenuates and high-fat diet exacerbates the metastasis-associated bone wasting.

FXYD5 (dysadherin) may mediate metastatic progression through regulation of the β-Na+-K+-ATPase subunit in the 4T1 mouse breast cancer model

FXYD5 is a Na+-K+-ATPase regulator, expressed in a variety of normal epithelia. In parallel, it has been found to be associated with several types of cancer and effect lethal outcome by promoting metastasis. However, the molecular mechanism underlying FXYD5 mediated invasion has not yet been identified. In this study, using in vivo 4T1 murine breast cancer model, we found that FXYD5-specific shRNA significantly inhibited lung cancer metastasis, without having a substantial effect on primary tumor growth. Our study reveals that FXYD5 participates in multiple stages of metastatic development and exhibits more than one mode of E-cadherin regulation. We provide the first evidence that FXYD5-related morphological changes are mediated through its interaction with Na+-K+-ATPase. Experiments in cultured 4T1 cells have indicated that FXYD5 expression may downregulate the β1 isoform of the pump. This behavior could have implications on both transcellular interactions and intracellular events. Further studies suggest that differential localization of the adaptor protein Annexin A2 in FXYD5-expressing cells may correlate with matrix metalloproteinase 9 secretion and adhesion changes in 4T1 wild-type cells.

FXYD5 Is an Essential Mediator of the Inflammatory Response during Lung Injury

The alveolar epithelium secretes cytokines and chemokines that recruit immune cells to the lungs, which is essential for fighting infections but in excess can promote lung injury. Overexpression of FXYD5, a tissue-specific regulator of the Na,K-ATPase, in mice, impairs the alveolo-epithelial barrier, and FXYD5 overexpression in renal cells increases C-C chemokine ligand-2 (CCL2) secretion in response to lipopolysaccharide (LPS). The aim of this study was to determine whether FXYD5 contributes to the lung inflammation and injury. Exposure of alveolar epithelial cells (AEC) to LPS increased FXYD5 levels at the plasma membrane, and FXYD5 silencing prevented both the activation of NF-κB and the secretion of cytokines in response to LPS. Intratracheal instillation of LPS into mice increased FXYD5 levels in the lung. FXYD5 overexpression increased the recruitment of interstitial macrophages and classical monocytes to the lung in response to LPS. FXYD5 silencing decreased CCL2 levels, number of cells, and protein concentration in bronchoalveolar lavage fluid (BALF) after LPS treatment, indicating that FXYD5 is required for the NF-κB-stimulated epithelial production of CCL2, the influx of immune cells, and the increase in alveolo-epithelial permeability in response to LPS. Silencing of FXYD5 also prevented the activation of NF-κB and cytokine secretion in response to interferon α and TNF-α, suggesting that pro-inflammatory effects of FXYD5 are not limited to the LPS-induced pathway. Furthermore, in the absence of other stimuli, FXYD5 overexpression in AEC activated NF-κB and increased cytokine production, while FXYD5 overexpression in mice increased cytokine levels in BALF, indicating that FXYD5 is sufficient to induce the NF-κB-stimulated cytokine secretion by the alveolar epithelium. The FXYD5 overexpression also increased cell counts in BALF, which was prevented by silencing the CCL2 receptor (CCR2), or by treating mice with a CCR2-blocking antibody, confirming that FXYD5-induced CCL2 production leads to the recruitment of monocytes to the lung. Taken together, the data demonstrate that FXYD5 is a key contributor to inflammatory lung injury.

Autocrine MCP-1/CCR2 signaling stimulates proliferation and migration of renal carcinoma cells

The chemokine monocyte chemoattractant protein-1 [MCP-1; also known as chemokine (C-C motif) ligand 2] is an important mediator of monocyte recruitment during inflammatory processes. Pathologically high expression levels of MCP-1 by tumor cells have been observed in a variety of cancer types. In the majority of cases, high MCP-1 expression is associated with a poor prognosis, as infiltration of the tumor with inflammatory monocytes promotes tumor progression and metastasis. MCP-1 is also expressed in renal cell carcinoma (RCC). In the present study, the function and the regulation of MCP-1 was investigated in two RCC cell lines, CaKi-1 and 786-O. In both cell lines, expression of MCP-1 was significantly enhanced compared with non-cancerous control cells. As expected, secretion of MCP-1 into the medium facilitated the recruitment of peripheral blood monocytes via the chemokine (C-C motif) receptor type 2 (CCR2). As expression of CCR2 was also detected in 786-O and CaKi-1 cells, the effect of autocrine MCP-1/CCR2 signaling was evaluated in these cells. In proliferation assays, administration of an MCP-1 neutralizing antibody or of a CCR2 antagonist to CaKi-1 and 786-O cells significantly decreased cell growth; supplementation of the growth medium with recombinant human MCP-1 had no additional effect on proliferation. The migration ability of RCC cells was impaired by MCP-1 neutralization or pharmacological CCR2 inhibition, while it was stimulated by the addition of recombinant human MCP-1, compared with untreated control cells. Finally, substantial differences in the regulation of MCP-1 expression were observed between RCC cell lines. In CaKi-1 cells, expression of MCP-1 appears to be largely mediated by the transcription factor nuclear factor of activated T cells 5, while in 786-O cells, deletion of the tumor suppressor gene Von-Hippel-Lindau appeared to be responsible for MCP-1 upregulation, as suggested by previous studies. Taken together, the results of the current study indicate that expression of MCP-1 in RCC cells promotes tumor progression and metastasis not only by paracrine, but also by autocrine, MCP-1/CCR2 signaling events, enhancing cell proliferation and migration ability. Therefore, the present findings suggest the MCP-1/CCR2 axis is a potential target for future therapeutic strategies in the treatment of metastatic RCC.

The O-glycosylated ectodomain of FXYD5 impairs adhesion by disrupting cell-cell trans-dimerization of Na,K-ATPase β1 subunits

FXYD5 (also known as dysadherin), a regulatory subunit of the Na,K-ATPase, impairs intercellular adhesion by a poorly understood mechanism. Here, we determined whether FXYD5 disrupts the trans-dimerization of Na,K-ATPase molecules located in neighboring cells. Mutagenesis of the Na,K-ATPase β1 subunit identified four conserved residues, including Y199, that are crucial for the intercellular Na,K-ATPase trans-dimerization and adhesion. Modulation of expression of FXYD5 or of the β1 subunit with intact or mutated β1-β1 binding sites demonstrated that the anti-adhesive effect of FXYD5 depends on the presence of Y199 in the β1 subunit. Immunodetection of the plasma membrane FXYD5 was prevented by the presence of O-glycans. Partial FXYD5 deglycosylation enabled antibody binding and showed that the protein level and the degree of O-glycosylation were greater in cancer than in normal cells. FXYD5-induced impairment of adhesion was abolished by both genetic and pharmacological inhibition of FXYD5 O-glycosylation. Therefore, the extracellular O-glycosylated domain of FXYD5 impairs adhesion by interfering with intercellular β1-β1 interactions, suggesting that the ratio between FXYD5 and α1-β1 heterodimer determines whether the Na,K-ATPase acts as a positive or negative regulator of intercellular adhesion.

CWP232228 targets liver cancer stem cells through Wnt/β-catenin signaling: a novel therapeutic approach for liver cancer treatment

Liver cancer stem cells (CSCs) are resistant to conventional chemotherapy and radiation, which may destroy tumor masses, but not all liver CSCs contribute to tumor initiation, metastasis, and relapse. In the present study, we showed that liver CSCs with elevated Wnt/β-catenin signaling possess much greater self-renewal and clonogenic potential. We further documented that the increased clonogenic potential of liver CSCs is highly associated with changes in Wnt/β-catenin signaling and that Wnt/β-catenin signaling activity is positively correlated with CD133 expression and aldehyde dehydrogenase (ALDH) enzymatic activity. Notably, the small molecule inhibitor CWP232228, which antagonizes the binding of β-catenin to TCF in the nucleus, inhibits Wnt/β-catenin signaling and depletes CD133+/ALDH+ liver CSCs, thus ultimately diminishing the self-renewal capacity of CSCs and decreasing tumorigenicity in vitro and in vivo. Taken together, our findings suggest that CWP232228 acts as a candidate therapeutic agent for liver cancer by preferentially targeting liver CSCs.

FXYD5: Na(+)/K(+)-ATPase Regulator in Health and Disease

FXYD5 (Dysadherin, RIC) is a single span type I membrane protein that plays multiple roles in regulation of cellular functions. It is expressed in a variety of epithelial tissues and acts as an auxiliary subunit of the Na⁺/K⁺-ATPase. During the past decade, a correlation between enhanced expression of FXYD5 and tumor progression has been established for various tumor types. In this review, current knowledge on FXYD5 is discussed, including experimental data on the functional effects of FXYD5 on the Na⁺/K⁺-ATPase. FXYD5 modulates cellular junctions, influences chemokine production, and affects cell adhesion. The accumulated data may provide a basis for understanding the molecular mechanisms underlying FXYD5 mediated phenotypes.

FXYD5 Protein Has a Pro-inflammatory Role in Epithelial Cells

The FXYD proteins are a family of small membrane proteins that share an invariant four amino acid signature motif F-X-Y-D and act as tissue-specific regulatory subunits of the Na,K-ATPase. FXYD5 (also termed dysadherin or RIC) is a structurally and functionally unique member of the FXYD family. As other FXYD proteins, FXYD5 specifically interacts with the Na,K-ATPase and alters its kinetics by increasing Vmax However, unlike other family members FXYD5 appears to have additional functions, which cannot be readily explained by modulation of transport kinetics. Knockdown of FXYD5 in MDA-MB-231 breast cancer cells largely decreases expression and secretion of the chemokine CCL2 (MCP-1). A related effect has also been observed in renal cell carcinoma cells. The current study aims to further characterize the relationship between the expression of FXYD5 and CCL2 secretion. We demonstrate that transfection of M1 epithelial cell line with FXYD5 largely increases lipopolysaccharide (LPS) stimulated CCL2 mRNA and secretion of the translated protein. We have completed a detailed analysis of the molecular events leading to the above response. Our key findings indicate that FXYD5 generates a late response by increasing the surface expression of the TNFα receptor, without affecting its total protein level, or mRNA transcription. LPS administration to mice demonstrates induced secretion of CCL2 and TNFα in FXYD5-expressing lung peripheral tissue, which suggests a possible role for FXYD5 in normal epithelia during inflammation.

The Wnt/β-catenin signaling/Id2 cascade mediates the effects of hypoxia on the hierarchy of colorectal-cancer stem cells

Hypoxia, a feature common to most solid tumors, is known to regulate many aspects of tumorigenesis. Recently, it was suggested that hypoxia increased the size of the cancer stem-cell (CSC) subpopulations and promoted the acquisition of a CSC-like phenotype. However, candidate hypoxia-regulated mediators specifically relevant to the stemness-related functions of colorectal CSCs have not been examined in detail. In the present study, we showed that hypoxia specifically promoted the self-renewal potential of CSCs. Through various in vitro studies, we found that hypoxia-induced Wnt/β-catenin signaling increased the occurrence of CSC-like phenotypes and the level of Id2 expression in colorectal-cancer cells. Importantly, the levels of hypoxia-induced CSC-sphere formation and Id2 expression were successfully attenuated by treatment with a Wnt/β-catenin-signaling inhibitor. We further demonstrated, for the first time, that the degree of hypoxia-induced CSC-sphere formation (CD44(+) subpopulation) in vitro and of tumor metastasis/dissemination in vivo were markedly suppressed by knocking down Id2 expression. Taken together, these data suggested that Wnt/β-catenin signaling mediated the hypoxia-induced self-renewal potential of colorectal-cancer CSCs through reactivating Id2 expression.

Targeting multiple tyrosine kinase receptors with Dovitinib blocks invasion and the interaction between tumor cells and cancer-associated fibroblasts in breast cancer

A constitutive and dynamic interaction between tumor cells and their surrounding stroma is a prerequisite for tumor invasion and metastasis. Fibroblasts and myofibroblasts (collectively called cancer associated fibroblasts, CAFs) often represent the major cellular components of tumor stroma. Tumor cells secret different growth factors which induce CAFs proliferation and differentiation, and, consequently, CAFs secrete different chemokines, cytokines or growth factors which induce tumor cell invasion and metastasis. In this study we showed here that CAFs from breast cancer surgical specimens significantly induced the invasion of breast cancer cells in vitro. Most interestingly, the novel multiple tyrosine kinase inhibitor Dovitinib significantly blocked the CAFs-induced invasion of breast cancer cells by, at least in part, inhibition of the expression and secretion of CCL2, CCL5 and VEGF in CAFs. Inhibition of PI3K/Akt/mTOR signaling could be responsible for the effects of Dovitinib, since Dovitinib antagonized the promoted phosphorylated Akt after treatment with PDGF, FGF or breast cancer cell-conditioned media. Treatment with Dovitinib in combination with PI3K/Akt/mTOR signaling inhibitors Ly294002 or RAD001 resulted in additive inhibition of cell invasion. This is the first in vitro study to show that the multiple tyrosine kinase inhibitor has therapeutic activities against breast cancer metastasis by targeting both tumor cells and CAFs.

Deciphering mechanisms of drug sensitivity and resistance to Selective Inhibitor of Nuclear Export (SINE) compounds

BACKGROUND

Exportin 1 (XPO1) is a well-characterized nuclear export protein whose expression is up-regulated in many types of cancers and functions to transport key tumor suppressor proteins (TSPs) from the nucleus. Karyopharm Therapeutics has developed a series of small-molecule Selective Inhibitor of Nuclear Export (SINE) compounds, which have been shown to block XPO1 function both in vitro and in vivo. The drug candidate, selinexor (KPT-330), is currently in Phase-II/IIb clinical trials for treatment of both hematologic and solid tumors. The present study sought to decipher the mechanisms that render cells either sensitive or resistant to treatment with SINE compounds, represented by KPT-185, an early analogue of KPT-330.

METHODS

Using the human fibrosarcoma HT1080 cell line, resistance to SINE was acquired over a period of 10 months of constant incubation with increasing concentration of KPT-185. Cell viability was assayed by MTT. Immunofluorescence was used to compare nuclear export of TSPs. Fluorescence activated cell sorting (FACS), quantitative polymerase chain reaction (qPCR), and immunoblots were used to measure effects on cell cycle, gene expression, and cell death. RNA from naïve and drug treated parental and resistant cells was analyzed by Affymetrix microarrays.

RESULTS

Treatment of HT1080 cells with gradually increasing concentrations of SINE resulted in >100 fold decrease in sensitivity to SINE cytotoxicity. Resistant cells displayed prolonged cell cycle, reduced nuclear accumulation of TSPs, and similar changes in protein expression compared to parental cells, however the magnitude of the protein expression changes were more significant in parental cells. Microarray analyses comparing parental to resistant cells indicate that a number of key signaling pathways were altered in resistant cells including expression changes in genes involved in adhesion, apoptosis, and inflammation. While the patterns of changes in transcription following drug treatment are similar in parental and resistant cells, the extent of response was more robust in the parental cells.

CONCLUSIONS

These results suggest that SINE resistance is conferred by alterations in signaling pathways downstream of XPO1 inhibition. Modulation of these pathways could potentially overcome the resistance to nuclear export inhibitors.

Epithelioid Sarcoma: Opportunities for Biology-Driven Targeted Therapy

Epithelioid sarcoma (ES) is a soft tissue sarcoma of children and young adults for which the preferred treatment for localized disease is wide surgical resection. Medical management is to a great extent undefined, and therefore for patients with regional and distal metastases, the development of targeted therapies is greatly desired. In this review, we will summarize clinically relevant biomarkers (e.g., SMARCB1, CA125, dysadherin, and others) with respect to targeted therapeutic opportunities. We will also examine the role of EGFR, mTOR, and polykinase inhibitors (e.g., sunitinib) in the management of local and disseminated disease. Toward building a consortium of pharmaceutical, academic, and non-profit collaborators, we will discuss the state of resources for investigating ES with respect to cell line resources, tissue banks, and registries so that a roadmap can be developed toward effective biology-driven therapies.

Blockade of Wnt/β-catenin signaling suppresses breast cancer metastasis by inhibiting CSC-like phenotype

The identification of cancer stem cells (CSCs) represents an important milestone in the understanding of chemodrug resistance and cancer recurrence. More specifically, some studies have suggested that potential metastasis-initiating cells (MICs) might be present within small CSC populations. The targeting and eradication of these cells represents a potential strategy for significantly improving clinical outcomes. A number of studies have suggested that dysregulation of Wnt/β-catenin signaling occurs in human breast cancer. Consistent with these findings, our previous data have shown that the relative level of Wnt/β-catenin signaling activity in breast cancer stem cells (BCSCs) is significantly higher than that in bulk cancer cells. These results suggest that BCSCs could be sensitive to therapeutic approaches targeting Wnt/β-catenin signaling pathway. In this context, abnormal Wnt/β-catenin signaling activity may be an important clinical feature of breast cancer and a predictor of poor survival. We therefore hypothesized that Wnt/β-catenin signaling might regulate self-renewal and CSC migration, thereby enabling metastasis and systemic tumor dissemination in breast cancer. Here, we investigated the effects of inhibiting Wnt/β-catenin signaling on cancer cell migratory potential by examining the expression of CSC-related genes, and we examined how this pathway links metastatic potential with tumor formation in vitro and in vivo.

Breast cancer: coordinated regulation of CCL2 secretion by intracellular glycosaminoglycans and chemokine motifs

The chemokine CCL2 (MCP-1) has been identified as a prominent tumor-promoting factor in breast cancer. The major source for CCL2 is in the tumor cells; thus, identifying the mechanisms regulating CCL2 release by these cells may enable the future design of modalities inhibiting CCL2 secretion and consequently reduce tumorigenicity. Using cells deficient in expression of glycosaminoglycans (GAGs) and short hairpin RNAs reducing heparan sulfate (HS) and chondroitin sulfate (CS) expression, we found that intracellular HS and CS (= GAGs) partly controlled the trafficking of CCL2 from the Golgi toward secretion. Next, we determined the secretion levels of GFP-CCL2-WT and GFP-CCL2-variants mutated in GAG-binding domains and/or in the 40s loop of CCL2 (⁴⁵TIVA⁴⁸). We have identified partial roles for R18+K19, H66, and the ⁴⁵TIVA⁴⁸ motif in regulating CCL2 secretion. We have also demonstrated that in the absence of R24 or R18+K19 +⁴⁵TIVA⁴⁸, the secretion of CCL2 by breast tumor cells was almost abolished. Analyses of the intracellular localization of GFP-CCL2-mutants in the Golgi or the endoplasmic reticulum revealed particular intracellular processes in which these CCL2 sequences controlled its intracellular trafficking and secretion. The R24, ⁴⁵TIVA⁴⁸ and R18+K19 +⁴⁵TIVA⁴⁸ domains controlled CCL2 secretion also in other cell types. We propose that targeting these chemokine regions may lead to reduced secretion of CCL2 by breast cancer cells (and potentially also by other malignant cells). Such a modality may limit tumor growth and metastasis, presumably without affecting general immune activities (as discussed below).

Wnt/β-Catenin Small-Molecule Inhibitor CWP232228 Preferentially Inhibits the Growth of Breast Cancer Stem-like Cells

Breast cancer stem cells (BCSC) are resistant to conventional chemotherapy and radiotherapy, which may destroy tumor masses but not all BCSC that can mediate relapses. In the present study, we showed that the level of Wnt/β-catenin signaling in BCSC is relatively higher than in bulk tumor cells, contributing to a relatively higher level of therapeutic resistance. We designed a highly potent small-molecule inhibitor, CWP232228, which antagonizes binding of β-catenin to T-cell factor (TCF) in the nucleus. Notably, although CWP232228 inhibited the growth of both BCSC and bulk tumor cells by inhibiting β-catenin-mediated transcription, BCSC exhibited greater growth inhibition than bulk tumor cells. We also documented evidence of greater insulin-like growth factor-I (IGF-I) expression by BCSC than by bulk tumor cells and that CWP232228 attenuated IGF-I-mediated BCSC functions. These results suggested that the inhibitory effect of CWP232228 on BCSC growth might be achieved through the disruption of IGF-I activity. Taken together, our findings indicate that CWP232228 offers a candidate therapeutic agent for breast cancer that preferentially targets BCSC as well as bulk tumor cells.

Paraoxonases and chemokine (C-C motif) ligand-2 in noncommunicable diseases

Oxidative stress and inflammation underpin most diseases; their mechanisms are inextricably linked. Chronic inflammation is associated with oxidation, anti-inflammatory cascades are linked to decreased oxidation, increased oxidative stress triggers inflammation, and redox balance inhibits the inflammatory cellular response. Whether or not oxidative stress and inflammation represent the cause or consequence of cellular pathology, they contribute significantly to the pathogenesis of noncommunicable diseases (NCD). The incidence of obesity and other related metabolic disturbances are increasing, as are age-related diseases due to a progressively aging population. Relationships between oxidative stress, inflammatory signaling, and metabolism are, in the broad sense of energy transformation, being increasingly recognized as part of the problem in NCD. In this chapter, we summarize the pathologic consequences of an imbalance between circulating and cellular paraoxonases, the system for scavenging excessive reactive oxygen species and circulating chemokines. They act as inducers of migration and infiltration of immune cells in target tissues as well as in the pathogenesis of disease that perturbs normal metabolic function. This disruption involves pathways controlling lipid and glucose homeostasis as well as metabolically driven chronic inflammatory states that encompass several response pathways. Dysfunction in the endoplasmic reticulum and/or mitochondria represents an important feature of chronic disease linked to oxidation and inflammation seen as self-reinforcing in NCD. Therefore, correct management requires a thorough understanding of these relationships and precise interpretation of laboratory test results.

Enhancement of paclitaxel and carboplatin therapies by CCL2 blockade in ovarian cancers

Ovarian cancer is associated with a leukocyte infiltrate and high levels of chemokines such as CCL2. We tested the hypothesis that CCL2 inhibition can enhance chemotherapy with carboplatin and paclitaxel. Elevated CCL2 expression was found in three non-MDR paclitaxel resistant ovarian cancer lines ES-2/TP, MES-OV/TP and OVCAR-3/TP, compared to parental cells. Mice xenografted with these cells were treated with the anti-human CCL2 antibody CNTO 888 and the anti-mouse MCP-1 antibody C1142, with and without paclitaxel or carboplatin. Our results show an additive effect of CCL2 blockade on the efficacy of paclitaxel and carboplatin. This therapeutic effect was largely due to inhibition of mouse stromal CCL2. We show that inhibition of CCL2 can enhance paclitaxel and carboplatin therapy of ovarian cancer.

Bisphosphonates modulate vital functions of human osteoblasts and affect their interactions with breast cancer cells

Bisphosphonates (BPs) are in clinical use for the treatment of breast cancer patients with bone metastases. Their anti-resorptive effect is mainly explained by inhibition of osteoclast activity, but recent evidence also points to a direct action of BPs on bone-forming osteoblasts. However, the mechanisms how BPs influence osteoblasts and their interactions with breast cancer cells are still poorly characterized. Human osteoblasts isolated from bone specimens were characterized in depth by their expression of osteogenic marker genes. The influence of the nitrogen-containing BPs zoledronate (Zol), ibandronate (Iban), and pamidronate (Pam) on molecular and cellular functions of osteoblasts was assessed focusing on cell proliferation and viability, apoptosis, cytokine secretion, and osteogenic-associated genes. Furthermore, effects of BPs on osteoblast-breast tumor cell interactions were examined in an established in vitro model system. The BPs Zol and Pam inhibited cell viability of osteoblasts. This effect was mediated by an induction of caspase-dependent apoptosis in osteoblasts. By interfering with the mevalonate pathway, Zol also reduces the proliferation of osteoblasts. The expression of phenotypic markers of osteogenic differentiation was altered by Zol and Pam. In addition, both BPs strongly influenced the secretion of the chemokine CCL2 by osteoblasts. Breast cancer cells also responded to Zol and Pam with a reduced cell adhesion to osteoblast-derived extracellular matrix molecules and with a decreased migration in response to osteoblast-secreted factors. BPs revealed prominent effects on human osteoblasts. Zol and Pam as the most potent BPs affected not only the expression of osteogenic markers, osteoblast viability, and proliferation but also important osteoblast-tumor cell interactions. Changing the osteoblast metabolism by BPs modulates migration and adhesion of breast cancer cells as well.

High aldehyde dehydrogenase activity enhances stem cell features in breast cancer cells by activating hypoxia-inducible factor-2α

High aldehyde dehydrogenase (ALDH) activity has been recognized as a marker of cancer stem cells (CSCs) in breast cancer. In this study, we examined whether inhibition of ALDH activity suppresses stem-like cell properties in a 4T1 syngeneic mouse model of breast cancer. We found that ALDH-positive 4T1 cells showed stem cell-like properties in vitro and in vivo. Blockade of ALDH activity reduced the growth of CSCs in breast cancer cell lines. Treatment of mice with the ALDH inhibitor diethylaminobenzaldehyde (DEAB) significantly suppressed 4T1 cell metastasis to the lung. Recent evidence suggests that ALDH affects the response of stem cells to hypoxia; therefore, we examined a possible link between ALDH and hypoxia signaling in breast cancer. Hypoxia-inducible factor-2α (HIF-2α) was highly dysregulated in ALDH-positive 4T1 cells. We observed that ALDH was highly correlated with the HIF-2α expression in breast cancer cell lines and tissues. DEAB treatment of breast cancer cells reduced the expression of HIF-2α in vitro. In addition, reduction of HIF-2α expression suppressed in vitro self-renewal ability and in vivo tumor initiation in ALDH-positive 4T1 cells. Therefore, our findings may provide the evidence necessary for exploring a new strategy in the treatment of breast cancer.

Importance of chemokine (CC-motif) ligand 2 in breast cancer

Breast cancer is the leading cause of cancer-related death in women in the United States. Chemokine (CC-motif) ligand 2 (CCL2), an inflammatory cytokine and chemokine, is highly expressed within the tumor and stromal cell populations and has been associated with enhanced tumorigenesis. In breast cancer patients, CCL2 has been correlated with high tumor grade and has been shown to have significant prognostic value for relapse-free survival. CCL2 likely exerts its pro-tumorigenic effects through recruitment of tumor-associated macrophages (TAMs); TAMs promote a tumorigenic microenvironment through the induction of growth enhancers, angiogenic factors and inflammatory mediators. CCL2 may also stimulate angiogenesis independently of TAM recruitment as it is closely associated with several endothelial cell growth factors. Additionally, CCL2 has been implicated in several processes leading to metastatic establishment including the development of bone metastasis. It has also been reported to directly upregulate pro-tumorigenic inflammatory mediators, including regulated upon activation, normal T cell expressed and secreted (RANTES) and tumor necrosis factor-alpha (TNF-α). While there is emerging support for a tumor promoting role of CCL2 in breast cancer, additional research is required before CCL2 can be decisively established as a prognostic factor and/or treatment target in breast cancer.