A complex of cadherin 17 with desmocollin 1 and p120-catenin regulates colorectal cancer migration and invasion according to the cell phenotype.

BACKGROUND: Cadherin-17 (CDH17), a marker of differentiation in intestinal cells, binds and activates α2ß1 integrin to promote cell adhesion and proliferation in colorectal cancer (CRC) metastasis. Furthermore, CDH17 associates with p120- and ß-catenin in a manner yet to be fully elucidated. In this report, we explored the molecular mediators involved in this association, their contribution to CRC dissemination and potential therapeutic implications. METHODS: Proteomic and confocal analyses were employed to identify and validate CDH17 interactors. Functional characterization involved the study of proliferation, migration, and invasion in cell lines representative of various phenotypes. Immunohistochemistry was conducted on CRC tissue microarrays (TMA). In vivo animal experiments were carried out for metastatic studies. RESULTS: We found that desmocollin-1 (DSC1), a desmosomal cadherin, interacts with CDH17 via its extracellular domain. DSC1 depletion led to increased or decreased invasion in CRC cells displaying epithelial or mesenchymal phenotype, respectively, in a process mediated by the association with p120-catenin. Down-regulation of DSC1 resulted in an increased expression of p120-catenin isoform 1 in epithelial cells or a shift in cellular location in mesenchymal cells. Opposite results were observed after forced expression of CDH17. DSC1 is highly expressed in budding cells at the leading edge of the tumor and associates with poor prognosis in the stem-like, mesenchymal CRC subtypes, while correlates with a more favorable prognosis in the less-aggressive subtypes. In vivo experiments demonstrated that DSC1 silencing reduced tumor growth, liver homing, and metastasis in CRC mesenchymal cells. Furthermore, a synthetic peptide derived from CDH17, containing the NLV motif, effectively inhibited invasion and liver homing in vivo, opening up new possibilities for the development of novel therapies focused on desmosomal cadherins. CONCLUSIONS: These findings shed light on the multifaceted roles of CDH17, DSC1, and p120-catenin in CRC metastasis, offering insights into potential therapeutic interventions for targeting desmosomal cadherins in poorly-differentiated carcinomas.

Schnurri-3 drives tumor growth and invasion in cancer cells expressing interleukin-13 receptor alpha 2.

Interleukin 13 receptor alpha 2 (IL13Rα2) is a relevant therapeutic target in glioblastoma (GBM) and other tumors associated with tumor growth and invasion. In a previous study, we demonstrated that protein tyrosine phosphatase 1B (PTP1B) is a key mediator of the IL-13/IL13Rα2 signaling pathway. PTP1B regulates cancer cell invasion through Src activation. However, PTP1B/Src downstream signaling mechanisms that modulate the invasion process remain unclear. In the present research, we have characterized the PTP1B interactome and the PTP1B-associated phosphoproteome after IL-13 treatment, in different cellular contexts, using proteomic strategies. PTP1B was associated with proteins involved in signal transduction, vesicle transport, and with multiple proteins from the NF-κB signaling pathway, including Tenascin-C (TNC). PTP1B participated with NF-κB in TNC-mediated proliferation and invasion. Analysis of the phosphorylation patterns obtained after PTP1B activation with IL-13 showed increased phosphorylation of the transcription factor Schnurri-3 (SHN3), a reported competitor of NF-κB. SHN3 silencing caused a potent inhibition in cell invasion and proliferation, associated with a down-regulation of the Wnt/ß-catenin pathway, an extensive decline of MMP9 expression and the subsequent inhibition of tumor growth and metastasis in mouse models. Regarding clinical value, high expression of SHN3 was associated with poor survival in GBM, showing a significant correlation with the classical and mesenchymal subtypes. In CRC, SHN3 expression showed a preferential association with the mesenchymal subtypes CMS4 and CRIS-B. Moreover, SHN3 expression strongly correlated with IL13Rα2 and MMP9-associated poor prognosis in different cancers. In conclusion, we have uncovered the participation of SNH3 in the IL-13/IL13Rα2/PTP1B pathway to promote tumor growth and invasion. These findings support a potential therapeutic value for SHN3.

A prognostic six-gene expression risk-score derived from proteomic profiling of the metastatic colorectal cancer secretome.

The necessity to accurately predict recurrence and clinical outcome in early stage colorectal cancer (CRC) is critical to identify those patients who may benefit from adjuvant chemotherapy. Here, we developed and validated a gene-based risk-score algorithm for patient stratification and personalised treatment in early stage disease based on alterations in the secretion of metastasis-related proteins. A quantitative label-free proteomic analysis of the secretome of highly and poorly metastatic CRC cell lines with different genetic backgrounds revealed 153 differentially secreted proteins (fold-change >5). These changes in the secretome were validated at the transcriptomic level. Starting from 119 up-regulated proteins, a six-gene/protein-based prognostic signature composed of IGFBP3, CD109, LTBP1, PSAP, BMP1, and NPC2 was identified after sequential discovery, training, and validation in four different cohorts. This signature was used to develop a risk-score algorithm, named SEC6, for patient stratification. SEC6 risk-score components showed higher expression in the poor prognosis CRC subtypes: consensus molecular subtype 4 (CMS4), CRIS-B, and stem-like. High expression of the signature was also associated with patients showing dMMR, CIMP+ status, and BRAF mutations. In addition, the SEC6 signature was associated with lower overall survival, progression-free interval, and disease-specific survival in stage II and III patients. SEC6-based risk stratification indicated that 5-FU treatment was beneficial for low-risk patients, whereas only aggressive treatments (FOLFOX and FOLFIRI) provided benefits to high-risk patients in stages II and III. In summary, this novel risk-score demonstrates the value of the secretome compartment as a reliable source for the retrieval of biomarkers with high prognostic and chemotherapy-predictive capacity, providing a potential new tool for tailoring decision-making in patient care.

Interleukin 13 receptor alpha 2 (IL13Rα2): Expression, signaling pathways and therapeutic applications in cancer.

Interleukin 13 receptor alpha 2 (IL13Rα2) is increasingly recognized as a relevant player in cancer invasion and metastasis. Despite being initially considered a decoy receptor for dampening the levels of interleukin 13 (IL-13) in diverse inflammatory conditions, accumulating evidences in the last decades indicate the capacity of IL13Rα2 for mediating IL-13 signaling in cancer cells. The biological reasons behind the expression of this receptor with such extremely high affinity for IL-13 in cancer cells remain unclear. Elevated expression of IL13Rα2 is commonly associated with invasion, late stage and cancer metastasis that results in poor prognosis for glioblastoma, colorectal or breast cancer, among others. The discovery of new mediators and effectors of IL13Rα2 signaling has been critical for deciphering its underlying molecular mechanisms in cancer progression. Still, many questions about the effects of inflammation, the cancer type and the tumor degree in the expression of IL13Rα2 remain largely uncharacterized. Here, we review and discuss the current status of the IL13Rα2 biology in cancer, with particular emphasis in the role of inflammation-driven expression and the regulation of different signaling pathways. As IL13Rα2 implications in cancer continue to grow exponentially, we highlight new targeted therapies recently developed for glioblastoma, colorectal cancer and other IL13Rα2-positive tumors.

Inhibition of Liver Metastasis in Colorectal Cancer by Targeting IL-13/IL13Rα2 Binding Site with Specific Monoclonal Antibodies.

BACKGROUND: IL13Rα2 is reportedly a promising therapeutic target in different cancers. Still, no specific antagonists have reached the clinics yet. We investigated the use of a IL-13/IL13Rα2 binding motif, called D1, as a new target for the development of therapeutic monoclonal antibodies (mAbs) for colorectal cancer (CRC) metastasis. METHODS: IL13Rα2 D1 peptides were prepared and used for immunization and antibody development. Antibodies were tested for inhibition of cellular invasion through Matrigel using CRC cell lines. Effects of the mAbs on cell signaling, receptor internalization and degradation were determined by western blot and flow cytometry. Swiss nude mice were used for survival analysis after treatment with IL13Rα2-specific mAbs and metastasis development. RESULTS: IL13Rα2 D1 peptides were used to generate highly selective mAbs that blocked IL13/IL13Rα2-mediated SRC activation and cell invasion in colorectal cancer cells. Antibodies also provoked a significant reduction in cell adhesion and proliferation of metastatic cancer cells. Treatment with mAbs impaired the FAK, SRC and PI3K/AKT pathway activation. Blocking effectivity was shown to correlate with the cellular IL13Rα2 expression level. Despite mAb 5.5.4 partially blocked IL-13 mediated receptor internalization from the cancer cell surface it still promotes receptor degradation. Compared with other IL13Rα2-specific antibodies, 5.5.4 exhibited a superior efficacy to inhibit metastatic growth in vivo, providing a complete mouse survival in different conditions, including established metastasis. CONCLUSIONS: Monoclonal antibody 5.5.4 showed a highly selective blocking capacity for the interaction between IL-13 and IL13Rα2 and caused a complete inhibition of liver metastasis in IL13Rα2-positive colorectal cancer cells. This capacity might be potentially applicable to other IL13Rα2-expressing tumors.

CDH6-activated αIIbß3 crosstalks with α2ß1 to trigger cellular adhesion and invasion in metastatic ovarian and renal cancers.

Cadherin 6 (CDH6) is significantly overexpressed in advanced ovarian and renal cancers. However, the role of CDH6 in cancer metastasis is largely unclear. Here, we investigated the impact of CDH6 expression on integrin-mediated metastatic progression. CDH6 preferentially bound to αIIbß3 integrin, a platelet receptor scarcely expressed in cancer cells, and this interaction was mediated through the cadherin Arginine-glycine-aspartic acid (RGD) motif. Furthermore, CDH6 and CDH17 were found to interact with α2ß1 in αIIbß3low cells. Transient silencing of CDH6, ITGA2B, or ITGB3 genes caused a significant loss of proliferation, adhesion, invasion, and lung colonization through the downregulation of SRC, FAK, AKT, and ERK signaling. In ovarian and renal cancer cells, integrin αIIbß3 activation appears to be a prerequisite for proper α2ß1 activation. Interaction of αIIbß3 with CDH6, and subsequent αIIbß3 activation, promoted activation of α2ß1 and cell adhesion in ovarian and renal cancer cells. Additionally, monoclonal antibodies specific to the cadherin RGD motif and clinically approved αIIbß3 inhibitors could block pro-metastatic activity in ovarian and renal tumors. In summary, the interaction between CDH6 and αIIbß3 regulates α2ß1-mediated adhesion and invasion of ovarian and renal cancer metastatic cells and constitutes a therapeutic target of broad potential for treating metastatic progression.

Regulation of cytokine signaling through direct interaction between cytokine receptors and the ATG16L1 WD40 domain.

ATG16L1, an autophagy mediator that specifies the site of LC3 lipidation, includes a C-terminal domain formed by 7 WD40-type repeats (WD40 domain, WDD), the function of which is unclear. Here we show that the WDD interacts with the intracellular domain of cytokine receptors to regulate their signaling output in response to ligand stimulation. Using a refined version of a previously described WDD-binding amino acid motif, here we show that this element is present in the intracellular domain of cytokine receptors. Two of these receptors, IL-10RB and IL-2Rγ, recognize the WDD through the motif and exhibit WDD-dependent LC3 lipidation activity. IL-10 promotes IL-10RB/ATG16L1 interaction through the WDD, and IL-10 signaling is suboptimal in cells lacking the WDD owing to delayed endocytosis and inefficient early trafficking of IL10/IL-10R complexes. Our data reveal WDD-dependent roles of ATG16L1 in the regulation of cytokine receptor trafficking and signaling, and provide a WDD-binding motif that might be used to identify additional WDD activators.

Protein Tyrosine Phosphatase-1B Inhibition Disrupts IL13Rα2-Promoted Invasion and Metastasis in Cancer Cells.

Background: Interleukin 13 receptor alpha 2 subunit (IL13Rα2) is overexpressed in glioblastoma (GBM), metastatic colorectal cancer (CRC) and ovarian cancer (OC). Here, we investigated the IL13Rα2 interactome searching for novel targets in cancer invasion and metastasis. Methods: The interactome of IL13Rα2 was determined in GBM by using a proteomic analysis and then validated in CRC and OC. Cell signaling was investigated using siRNA interference, protein tyrosine phosphatase-1B (PTP1B) inhibitors and Western blot analysis. Animal models of GBM and metastatic CRC were used for testing PTP1B inhibitors. Results: PTP1B was identified and validated as a mediator of IL13Rα2 signaling. An in silico analysis revealed that PTP1B overexpression is associated with lower overall survival of patients in the three types of cancer. PTP1B silencing or treatment with Claramine, a PTP1B inhibitor, caused a significant decrease in IL-13-mediated adhesion, migration and invasion of IL13Rα2-expressing cancer cells by inhibiting the dephosphorylation of Src Tyr530 and consequently, the phosphorylation of Src Tyr419, AKT and ERK1/2. In addition, Claramine inhibited EGF-mediated activation of EGFR Tyr1068. In vivo treatment with Claramine caused a total inhibition of liver metastasis in mice inoculated with CRC cells and a significant increase in the survival of mice bearing intracranial GBM patient-derived xenografts. Conclusions: We have uncovered that IL13 signaling through IL13Rα2 requires PTP1B activity and therefore, PTP1B inhibition represents a promising therapeutic strategy in multiple types of cancer, including glioblastoma.