Notch1-WISP-1 axis determines the regulatory role of mesenchymal stem cell-derived stromal fibroblasts in melanoma metastasis

Reprogramming of cancer-associated fibroblasts by apoptotic cancer cells inhibits lung metastasis via Notch1-WISP-1 signaling

The interplay between apoptotic cancer cells and the tumor microenvironment modulates cancer progression and metastasis. Cancer-associated fibroblasts (CAFs) play a crucial role in promoting these events through paracrine communication. Here, we demonstrate that conditioned medium (CM) from lung CAFs exposed to apoptotic cancer cells suppresses TGF-β1-induced migration and invasion of cancer cells and CAFs. Direct exposure of CAFs to apoptotic 344SQ cells (ApoSQ) inhibited CAF migration and invasion and the expression of CAF activation markers. Enhanced secretion of Wnt-induced signaling protein 1 (WISP-1) by CAFs exposed to ApoSQ was required for these antimigratory and anti-invasive effects. Pharmacological inhibition of Notch1 activation or siRNA-mediated Notch1 silencing prevented WISP-1 production by CAFs and reversed the antimigratory and anti-invasive effects. Enhanced expression of the Notch ligand delta-like protein 1 on the surface of ultraviolet-irradiated apoptotic lung cancer cells triggered Notch1-WISP-1 signaling. Phosphatidylserine receptor brain-specific angiogenesis inhibitor 1 (BAI1)-Rac1 signaling, which facilitated efferocytosis by CAFs, participated in crosstalk with Notch1 signaling for optimal production of WISP-1. In addition, a single injection of ApoSQ enhanced WISP-1 production, suppressed the expression of CAF activation markers in isolated Thy1⁺ CAFs, and inhibited lung metastasis in syngeneic immunocompetent mice via Notch1 signaling. Treatment with CM from CAFs exposed to ApoSQ suppressed tumor growth and lung metastasis, whereas treatment with WISP-1-immunodepleted CM from CAFs exposed to ApoSQ reversed the antitumorigenic and antimetastatic effects. Therefore, treatment with CM from CAFs exposed to apoptotic lung cancer cells could be therapeutically applied to suppress CAF activation, thereby preventing cancer progression and metastasis.

Mechanistic Interrogation of Cell Transformation In Vitro: The Transformics Assay as an Exemplar of Oncotransformation

The Transformics Assay is an in vitro test which combines the BALB/c 3T3 Cell Transformation Assay (CTA) with microarray transcriptomics. It has been shown to improve upon the mechanistic understanding of the CTA, helping to identify mechanisms of action leading to chemical-induced transformation thanks to RNA extractions in specific time points along the process of in vitro transformation. In this study, the lowest transforming concentration of the carcinogenic benzo(a)pyrene (B(a)P) has been tested in order to find molecular signatures of initial events relevant for oncotransformation. Application of Enrichment Analysis (Metacore) to the analyses of the results facilitated key biological interpretations. After 72 h of exposure, as a consequence of the molecular initiating event of aryl hydrocarbon receptor (AhR) activation, there is a cascade of cellular events and microenvironment modification, and the immune and inflammatory responses are the main processes involved in cell response. Furthermore, pathways and processes related to cell cycle regulation, cytoskeletal adhesion and remodeling processes, cell differentiation and transformation were observed.

The CCN axis in cancer development and progression

Since the authors first reviewed this subject in 2016 significant progress has been documented in the CCN field with advances made in the understanding of how members of the CCN family of proteins, CCN1-6, contribute to the pathogenesis and progression, positive and negative, of a larger variety of cancers. As termed matricellular proteins, and more recently the connective communication network, it has become clearer that members of the CCN family interact complexly with other proteins in the extracellular microenvironment, membrane signaling proteins, and can also operate intracellularly at the transcriptional level. In this review we expand on this earlier information providing new detailed information and insights that appropriate a much greater involvement and importance of their role in multiple aspects of cancer. Despite all the new information many more questions have been raised and intriguing results generated that warrant greater investigation. In order to permit the reader to smoothly integrate the new information we discuss all relevant CCN members in the context of cancer subtypes. We have harmonized the nomenclature with CCN numbering for easier comparisons. Finally, we summarize what new has been learned and provide a perspective on how our knowledge about CCN1-6 is being used to drive new initiatives on cancer therapeutics.

The Role of Cancer-Associated Fibroblast as a Dynamic Player in Mediating Cancer Stemness in the Tumor Microenvironment

The enrichment of cancer-associated fibroblast (CAFs) in a tumor microenvironment (TME) cultivates a pro-tumorigenic niche via aberrant paracrine signaling and matrix remodeling. A favorable niche is critical to the maintenance of cancer stem cells (CSCs), a population of cells that are characterized by their enhanced ability to self-renew, metastasis, and develop therapy resistance. Mounting evidence illustrates the interplay between CAF and cancer cells expedites malignant progression. Therefore, targeting the key cellular components and factors in the niche may promote a more efficacious treatment. In this study, we discuss how CAF orchestrates a niche that enhances CSC features and the potential therapeutic implication.

Converting melanoma-associated fibroblasts into a tumor-suppressive phenotype by increasing intracellular Notch1 pathway activity

Cancer-associated fibroblasts (CAFs) play a crucial role in cancer progression, drug resistance and tumor recurrence. We have recently shown that the Notch pathway determines the tumor-regulatory role of experimentally created ‘CAFs’. Here, we examined the status of Notch signaling in human melanoma-associated fibroblasts (MAFs) versus their normal counterparts and tested whether manipulation of the Notch pathway activity in MAFs alters their tumor-regulatory function. Using tissue microarrays, we found that MAFs exhibit decreased Notch pathway activity compared with normal fibroblasts in adjacent and non-adjacent skin. Consistently, MAFs isolated from human metastatic melanoma exhibited lower Notch activity than did normal human fibroblasts, demonstrating that Notch pathway activity is low in MAFs. We then investigated the effect of increasing Notch pathway activity in MAF on melanoma growth in co-cultures and in a mouse co-graft model. We found that activation of the Notch pathway in MAFs significantly restricted melanoma cell growth in vitro and suppressed melanoma skin growth and tumor angiogenesis in vivo. Our study demonstrates that the Notch signaling is inhibited in MAFs. Increase of Notch pathway activity can confer tumor-suppressive function on MAFs. Thus, targeting melanoma by activating Notch signaling in MAF may represent a novel therapeutic approach.

Notch1 signaling determines the plasticity and function of fibroblasts in diabetic wounds

Fibroblasts play a pivotal role in wound healing. However, the molecular mechanisms determining the reparative response of fibroblasts remain unknown. Here, we identify Notch1 signaling as a molecular determinant controlling the plasticity and function of fibroblasts in modulating wound healing and angiogenesis. The Notch pathway is activated in fibroblasts of diabetic wounds but not in normal skin and non-diabetic wounds. Consistently, wound healing in the FSP-1 ^+/- ;ROSA ^LSL-N1IC+/+ mouse, in which Notch1 is activated in fibroblasts, is delayed. Increased Notch1 activity in fibroblasts suppressed their growth, migration, and differentiation into myofibroblasts. Accordingly, significantly fewer myofibroblasts and less collagen were present in granulation tissues of the FSP-1 ^+/- ;ROSA ^LSL-N1IC+/+ mice, demonstrating that high Notch1 activity inhibits fibroblast differentiation. High Notch1 activity in fibroblasts diminished their role in modulating the angiogenic response. We also identified that IL-6 is a functional Notch1 target and involved in regulating angiogenesis. These findings suggest that Notch1 signaling determines the plasticity and function of fibroblasts in wound healing and angiogenesis, unveiling intracellular Notch1 signaling in fibroblasts as potential target for therapeutic intervention in diabetic wound healing.

The Matrix Revolution: Matricellular Proteins and Restructuring of the Cancer Microenvironment

The extracellular matrix (ECM) surrounding cells is indispensable for regulating their behavior. The dynamics of ECM signaling are tightly controlled throughout growth and development. During tissue remodeling, matricellular proteins (MCP) are secreted into the ECM. These factors do not serve classical structural roles, but rather regulate matrix proteins and cell-matrix interactions to influence normal cellular functions. In the tumor microenvironment, it is becoming increasingly clear that aberrantly expressed MCPs can support multiple hallmarks of carcinogenesis by interacting with various cellular components that are coupled to an array of downstream signals. Moreover, MCPs also reorganize the biomechanical properties of the ECM to accommodate metastasis and tumor colonization. This realization is stimulating new research on MCPs as reliable and accessible biomarkers in cancer, as well as effective and selective therapeutic targets.

Intracellular Notch1 Signaling in Cancer-Associated Fibroblasts Dictates the Plasticity and Stemness of Melanoma Stem/Initiating Cells

Cancer stem cells (CSCs) play critical roles in cancer initiation, metastasis, recurrence, and drug resistance. Recent studies have revealed involvement of cancer‐associated fibroblasts (CAFs) in regulating CSCs. However, the intracellular molecular mechanisms that determine the regulatory role of CAFs in modulating the plasticity of CSCs remain unknown. Here, we uncovered that intracellular Notch1 signaling in CAFs serves as a molecular switch, which modulates tumor heterogeneity and aggressiveness by inversely controlling stromal regulation of the plasticity and stemness of CSCs. Using mesenchymal stem cell‐derived fibroblasts (MSC‐DF) harboring reciprocal loss‐of‐function and gain‐of‐function Notch1 signaling, we found that MSC‐DF^{Notch1−/−} prompted cocultured melanoma cells to form more spheroids and acquire the phenotype (CD271⁺ and Nestin⁺) of melanoma stem/initiating cells (MICs), whereas MSC‐DF^N1IC+/+ suppressed melanoma cell sphere formation and mitigated properties of MICs. MSC‐DF^{Notch1−/−} increased stemness of CD271⁺ MIC, which resultantly exhibited stronger aggressiveness in vitro and in vivo, by upregulating Sox2/Oct4/Nanog expression. Consistently, when cografted with melanoma cells into NOD scid gamma (NSG) mice, MSC‐DF^{Notch1−/−} increased, but MSC‐DF^N1IC+/+ decreased, the amounts of CD271⁺ MIC in melanoma tissue. The amounts of CD271⁺ MIC regulated by MSC‐DF carrying high or low Notch1 pathway activity is well correlated with capability of melanoma metastasis, supporting that melanoma metastasis is MIC‐mediated. Our data demonstrate that intracellular Notch1 signaling in CAFs is a molecular switch dictating the plasticity and stemness of MICs, thereby regulating melanoma aggressiveness, and therefore that targeting the intracellular Notch1 signaling pathway in CAFs may present a new therapeutic strategy for melanoma. stem cells2019;37:865–875

WNT1-inducible signaling pathway protein 1 (WISP1/CCN4) stimulates melanoma invasion and metastasis by promoting the epithelial-mesenchymal transition

Besides intrinsic changes, malignant cells also release soluble signals that reshape their microenvironment. Among these signals is WNT1-inducible signaling pathway protein 1 (WISP1), a secreted matricellular protein whose expression is elevated in several cancers, including melanoma, and is associated with reduced survival of patients diagnosed with primary melanoma. Here, we found that WISP1 knockout increases cell proliferation and represses wound healing, migration, and invasion of mouse and human melanoma cells in multiple in vitro assays. Metastasis assays revealed that WISP1 knockout represses tumor metastasis of B16F10 and YUMM1.7 melanoma cells in both C57BL/6Ncrl and NOD-scid IL2Rγ^null (NSG) mice. WT B16F10 cells having an invasion phenotype in a transwell assay possessed a gene expression signature similar to that observed in the epithelial-mesenchymal transition (EMT), including E-cadherin repression and fibronectin and N-cadherin induction. Upon WISP1 knockout, expression of these EMT signature genes went in the opposite direction in both mouse and human cell lines, and EMT-associated gene expression was restored upon exposure to media containing WISP1 or to recombinant WISP1 protein. In vivo, Wisp1 knockout-associated metastasis repression was reversed by the reintroduction of either WISP1 or snail family transcriptional repressor 1 (SNAI1). Experiments testing EMT gene activation and inhibition with recombinant WISP1 or kinase inhibitors in B16F10 and YUMM1.7 cells suggested that WISP1 activates AKT Ser/Thr kinase and that MEK/ERK signaling pathways shift melanoma cells from proliferation to invasion. Our results indicate that WISP1 present within the tumor microenvironment stimulates melanoma invasion and metastasis by promoting an EMT-like process.

The emerging role of WISP proteins in tumorigenesis and cancer therapy

Accumulated evidence has demonstrated that WNT1 inducible signaling pathway protein (WISP) genes, which belong to members of the CCN growth factor family, play a pivotal role in tumorigenesis and progression of a broad spectrum of human cancers. Mounting studies have identified that WISP proteins (WISP1-3) exert different biological functions in various human malignancies. Emerging evidence indicates that WISP proteins are critically involved in cell proliferation, apoptosis, invasion and metastasis in cancers. Because the understanding of a direct function of WISP proteins in cancer development and progression has begun to emerge, in this review article, we describe the physiological function of WISP proteins in a variety of human cancers. Moreover, we highlight the current understanding of how the WISP protein is involved in tumorigenesis and cancer progression. Furthermore, we discuss that targeting WISP proteins could be a promising strategy for the treatment of human cancers. Hence, the regulation of WISP proteins could improve treatments for cancer patients.

LncRNA FOXC2-AS1 protects cardiomyocytes from doxorubicin-induced cardiotoxicity through activation of WNT1-inducible signaling pathway protein-1

Doxorubicin (Dox) is an anthracycline antibiotic that has been used to treat different cancers. Dox-induced cardiotoxicity is common in clinical practice, while its mechanism is unknown. It has been proved that lncRNA FOXC2-AS1 may promote doxorubicin resistance and WNT1-inducible signaling pathway protein-1 (WISP1) blocks doxorubicin-induced cardiomyocyte death. Our study aimed to investigate the involvement of lncRNA FOXC2-AS1 and WISP1 in doxorubicin-induced cardiotoxicity and to explore their interactions. In our study we observed that FOXC2-AS1 and WISP1 mRNA were downregulated in heart tissues of mice with Dox-induced cardiotoxicity. FOXC2-AS1 and WISP1 mRNA expression were positively correlated in mice with Dox-induced cardiotoxicity but not in healthy mice. Overexpression of FOXC2-AS1 promoted to viability of mice cardiomyocytes under Dox treatment and also increased the expression level of WISP1. In contrast, WISP1 overexpression showed no significant effect on FOXC2-AS1. We therefore conclude that lncRNA FOXC2-AS1 may upregulate WISP1 to protect cardiomyocytes from doxorubicin-induced cardiotoxicity.

The role of CCN4/WISP-1 in the cancerous phenotype

CCN proteins are secreted into the extracellular environment where they interact with both components of the extracellular matrix and with cell surface receptors to regulate cellular function. Through these interactions, CCNs act as extracellular ligands to activate intracellular signal transduction pathways. CCN4/WISP-1, like other CCNs, plays multiple physiologic roles in development and also participates in pathogenesis. CCN4 is of particular interest with respect to cancer, showing promise as a biomarker or prognostic factor as well as a potential therapeutic target. This review focuses on recent work addressing the role of CCN4 in cancer. While CCN4 has been identified as an oncogene in a number of cancers, where it enhances cell migration and promoting epithelial-mesenchymal transition, there are other cancers where CCN4 appears to play an inhibitory role. The mechanisms underlying these differences in cellular response have not yet been delineated, but are an active area of investigation. The expression and activities of CCN4 splice variants are likewise an emerging area for study. CCN4 acts as an autocrine factor that regulates the cancer cells from which it is secreted. However, CCN4 is also a paracrine factor that is secreted by stromal fibroblasts, and can affect the function of vascular endothelial cells. In summary, current evidence is abundant in regard to establishing potential roles for CCN4 in oncogenesis, but much remains to be learned about the functions of this fascinating protein as both an autocrine and paracrine regulator in the tumor microenvironment.

MicroRNA-143-3p inhibits growth and invasiveness of melanoma cells by targeting cyclooxygenase-2 and inversely correlates with malignant melanoma progression

Malignant melanoma is one of the most leading form of skin cancer associated with a low patient survival rate. Increasing evidence revealed that microRNAs (miRNAs) play a crucial role in the occurrence and development of several form of cancer including melanoma. In this study, we aimed at investigating the expression and role of miR-143-3p in human malignant melanoma. Our results showed that the expression of miR-143-3p was lower in human melanoma cells, as well as human biopsy specimens, when compared to normal human melanocytes. Ectopic expression of miR-143-3p in human melanoma cells inhibited proliferation, migration, invasion and promoted apoptosis acting through a molecular mechanism that, at least in part, is dependent on inhibition of cyclooxygenase-2 (COX-2) gene. Collectively, these results demonstrate that miR-143-3p could represent at the same time, a new early diagnostic marker and therapeutic target acting as tumor suppressor in melanoma cancer.

Tp53 Mutation Inhibits Ubiquitination and Degradation of WISP1 via Down-Regulation of Siah1 in Pancreatic Carcinogenesis

Wnt1 inducible signaling pathway protein-1 (WISP1) may play an important role in promoting carcinogenesis. However, the biological function and underlying mechanism of WISP1 in pancreatic carcinogenesis still remains enigmatic. In this study, immunochemistry staining showed that protein levels of WISP1 were more significantly upregulated in pancreatic ductal adenocarcinoma (PDAC) tissues with Tp53 mutation than in PDAC tissues with Tp53 wild-type. In addition, a significant correlation was observed between increased malignant phenotype of tumors from well-differentiated adenocarcinoma tissues to moderately- or poorly-differentiated adenocarcinoma tissues shifting from cytoplasmic expression to nuclear accumulation of WISP1. Interestingly, WISP1 expression was correlated with the poor prognosis in PDAC patients with Tp53 mutation. Also, the biological function analysis showed that WISP1 may act as a potential oncogene in PDAC cells. In addition, immunofluorescence analysis showed that Tp53 mutation promoted WISP1 expression in PanIN and PDAC cells, while Siah E3 Ubiquitin Protein Ligase 1 (Siah1) inhibited WISP1 expression in PDAC cells. Moreover, through immunoprecipitation, immunoblotting analysis, in vitro binding assay, and ubiquitination assay, we found that Tp53 mutation inhibited ubiquitination and degradation of Siah1-dependent WISP1. Therefore, Tp53 mutation-Siah1-WISP1 is a new signaling pathway, playing an important role in pancreatic carcinogenesis.

Identification of CD24 as a marker for tumorigenesis of melanoma

Objective

Cutaneous melanoma (CM) is a common skin cancer. Surgery is still the primary treatment for CM, as melanoma is resistant to chemotherapy. In the recent years, it has been found that cancer stem-like cells (CSCs) are responsible for this drug resistance. CD24 is a widely used marker to isolate CSCs. In this study, we aimed to analyze the properties of CD24⁺ and CD24^- subpopulation of melanoma cells.

Materials and methods

We isolated CD24⁺ cells CSCs using magnetic-activated cell sorting system. We extracted total RNA and carried out reverse transcription polymerase chain reaction analysis. We counted the cell colonies using soft agar assay and assessed the cell invasion using cell migration assay. We implanted CD24⁺ or CD24^- cells into the flank of non-obese diabetic severe combined immunodeficiency mice, and measured the tumor volumes every 5 days until the end of the experiment. We carried out immunohistochemical analysis to study the tissue sections.

Results

We demonstrated that the CD24⁺ subpopulation has self-renewal properties in vitro and in vivo by using soft agar assay and xenograft tumor model. Furthermore, we confirmed that CD24 expression is accompanied by activation of Notch1 signaling pathway.

Conclusion

This study provides new knowledge on the role of CD24 in the tumorigenic ability of melanoma.