Cancer-associated fibroblasts (CAF) are major mediators in tumor microenvironment. We investigated the changes in protein expression in colon cancer-associated fibroblasts compared with normal ...fibroblasts (NF) in the context of searching for prognostic biomarkers, particularly for stage II patients.
CAFs and NFs isolated from colon cancer patients were used to identify differentially expressed proteins using quantitative proteomics. Stromal expression of deregulated proteins was analyzed by IHC. Prognostic impact was studied using external gene-expression datasets for training, then quantitative PCR and IHC for validation in different cohorts of patients. Combined datasets were used for prediction of risk assessment at stages II and III.
A desmoplastic signature composed of 32 proteins, highly specific for stromal components in colon cancer, was identified. These proteins were enriched for extracellular matrix organization components, TGFβ signaling pathway, fibrosis, and wound-healing proteins. The expression in CAFs of 11 upregulated proteins and four downregulated proteins, selected for biomarker validation, was verified by orthogonal techniques. LOXL2 displayed a high prognostic impact by using external independent datasets and further validation in two different cohorts of patients. High expression of LOXL2 was associated with higher recurrence P = 0.001 HR, 5.38 95% confidence interval (CI), 1.70-17.01 and overall survival P = 0.001 HR, 8.52 (95% CI, 1.90-38.29). IHC analysis revealed a prognostic value for LOXL2 in stage II patients.
We identified LOXL2 to be associated with the outcome of colon cancer patients. Furthermore, it can be used to stratify patients at stages II and III for further therapeutic decisions.
Expression of Snail1 in epithelial cells triggers an epithelial-mesenchymal transition (EMT). Here, we demonstrate that the synthesis of Zeb2, a transcriptional repressor of E-cadherin, is ...up-regulated after Snail1-induced EMT. Snail1 does not affect the synthesis of Zeb2 mRNA, but prevents the processing of a large intron located in its 5'-untranslated region (UTR). This intron contains an internal ribosome entry site (IRES) necessary for the expression of Zeb2. Maintenance of 5'-UTR Zeb2 intron is dependent on the expression of a natural antisense transcript (NAT) that overlaps the 5' splice site in the intron. Ectopic overexpression of this NAT in epithelial cells prevents splicing of the Zeb2 5'-UTR, increases the levels of Zeb2 protein, and consequently down-regulates E-cadherin mRNA and protein. The relevance of these results is demonstrated by the strong association between NAT presence and conservation of the 5'-UTR intron in cells that have undergone EMT or in human tumors with low E-cadherin expression. Therefore, the results presented in this article reveal the existence of a NAT capable of activating Zeb2 expression, explain the mechanism involved in this activation, and demonstrate that this NAT regulates E-cadherin expression.
PARP inhibition can induce anti-neoplastic effects when used as monotherapy or in combination with chemo- or radiotherapy in various tumor settings; however, the basis for the anti-metastasic ...activities resulting from PARP inhibition remains unknown. PARP inhibitors may also act as modulators of tumor angiogenesis. Proteomic analysis of endothelial cells revealed that vimentin, an intermediary filament involved in angiogenesis and a specific hallmark of EndoMT (endothelial to mesenchymal transition) transformation, was down-regulated following loss of PARP-1 function in endothelial cells. VE-cadherin, an endothelial marker of vascular normalization, was up-regulated in HUVEC treated with PARP inhibitors or following PARP-1 silencing; vimentin over-expression was sufficient to drive to an EndoMT phenotype. In melanoma cells, PARP inhibition reduced pro-metastatic markers, including vasculogenic mimicry. We also demonstrated that vimentin expression was sufficient to induce increased mesenchymal/pro-metastasic phenotypic changes in melanoma cells, including ILK/GSK3-β-dependent E-cadherin down-regulation, Snail1 activation and increased cell motility and migration. In a murine model of metastatic melanoma, PARP inhibition counteracted the ability of melanoma cells to metastasize to the lung. These results suggest that inhibition of PARP interferes with key metastasis-promoting processes, leading to suppression of invasion and colonization of distal organs by aggressive metastatic cells.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Cancer-associated fibroblasts (CAF) actively participate in reciprocal communication with tumor cells and with other cell types in the microenvironment, contributing to a tumor-permissive ...neighborhood and promoting tumor progression. The aim of this study is the characterization of how CAFs from primary human colon tumors promote migration of colon cancer cells.
Primary CAF cultures from 15 primary human colon tumors were established. Their enrichment in CAFs was evaluated by the expression of various epithelial and myofibroblast specific markers. Coculture assays of primary CAFs with different colon tumor cells were performed to evaluate promigratory CAF-derived effects on cancer cells. Gene expression profiles were developed to further investigate CAF characteristics.
Coculture assays showed significant differences in fibroblast-derived paracrine promigratory effects on cancer cells. Moreover, the association between CAFs' promigratory effects on cancer cells and classic fibroblast activation or stemness markers was observed. CAF gene expression profiles were analyzed by microarray to identify deregulated genes in different promigratory CAFs. The gene expression signature, derived from the most protumorogenic CAFs, was identified. Interestingly, this "CAF signature" showed a remarkable prognostic value for the clinical outcome of patients with colon cancer. Moreover, this prognostic value was validated in an independent series of 142 patients with colon cancer, by quantitative real-time PCR (qRT-PCR), with a set of four genes included in the "CAF signature."
In summary, these studies show for the first time the heterogeneity of primary CAFs' effect on colon cancer cell migration. A CAF gene expression signature able to classify patients with colon cancer into high- and low-risk groups was identified.
Chemical descriptors encode the physicochemical and structural properties of small molecules, and they are at the core of chemoinformatics. The broad release of bioactivity data has prompted enriched ...representations of compounds, reaching beyond chemical structures and capturing their known biological properties. Unfortunately, bioactivity descriptors are not available for most small molecules, which limits their applicability to a few thousand well characterized compounds. Here we present a collection of deep neural networks able to infer bioactivity signatures for any compound of interest, even when little or no experimental information is available for them. Our signaturizers relate to bioactivities of 25 different types (including target profiles, cellular response and clinical outcomes) and can be used as drop-in replacements for chemical descriptors in day-to-day chemoinformatics tasks. Indeed, we illustrate how inferred bioactivity signatures are useful to navigate the chemical space in a biologically relevant manner, unveiling higher-order organization in natural product collections, and to enrich mostly uncharacterized chemical libraries for activity against the drug-orphan target Snail1. Moreover, we implement a battery of signature-activity relationship (SigAR) models and show a substantial improvement in performance, with respect to chemistry-based classifiers, across a series of biophysics and physiology activity prediction benchmarks.
Tumor epithelial cells within a tumor coexist with a complex microenvironment in which a variety of interactions between its various components determine the behavior of the primary tumors. ...Cancer‐associated fibroblasts (CAF) and M2 macrophages, characterized by high expression of different markers, including α‐SMA, FSP1 and FAP, or CD163 and DCSIGN, respectively, are involved in the malignancy of different tumors. In the present study, expression of the above markers in CAF and M2 macrophages was analyzed using RT‐PCR and immunohistochemistry in the normal mucosa and tumor tissue from a cohort of 289 colorectal cancer patients. Expression of CAF and M2 markers is associated with the clinical outcome of colorectal cancer patients. Moreover, the combination of CAF and M2 markers identifies three groups of patients with clear differences in the progression of the disease. This combined variable could be a decisive factor in the survival of advanced‐stage patients. Taken together, these analyses demonstrate the prognostic involvement of interrelationships between DCSIGN, CD163, α‐SMA, FSP1 and FAP markers in the survival of colon cancer patients.
E-cadherin (CDH1) gene expression is strictly regulated. The transcriptional factors SNAIL and ZEB1 are involved in its repression, whereas activation of vitamin D receptor (VDR) by vitamin D induces ...its transcription. We study the expression and functional correlation of SNAIL, CDH1, VDR and ZEB1 genes and examine their possible involvement in colon cancer. The expression of these four genes was measured by real time-PCR in 114 patients with colorectal cancer, and tumor characteristics were analyzed in each patient. SNAIL expression was associated with downregulation of CDH1 (P<0.001) and VDR (P<0.001) gene products. We also found a positive correlation between CDH1 and VDR expressions. However, the association between SNAIL and CDH1 was not found in patients with high expression of ZEB1. We observed a correlation between downregulation of: a) ZEB1 and presence of polyps in surgical resections; b) VDR and poor differentiation and c) CDH1 and poor differentiation, vascular invasion, presence of lymph node metastases and advanced stages; as well as a trend toward a correlation between SNAIL expression in tumors and vascular invasion. The correlations between SNAIL, CDH1, VDR and ZEB1 and the association between reduced expression of CDH1 and VDR and aggressive tumor characteristics emphasize the value of analyzing these genes in colon cancer patients for prognostic purposes and for predicting response to possible therapies with vitamin D or its analogs.
Met receptor phosphorylation is associated with poor prognosis in human small cell lung cancer (SCLC). The aim of our work was to investigate the effects of hepatocyte growth factor ...(HGF)/Met-mediated epithelial-to-mesenchymal transition (EMT) in SCLC and to evaluate the role of Met inhibition in mesenchymal/chemorefractory SCLC models.
SCLC models of HGF-induced EMT were evaluated in vitro and in vivo (subcutaneous xenografts in BALB/c nude mice) for chemosensitivity and response to Met inhibition with PF-2341066 (crizotinib). Human SCLC samples at diagnosis (N = 87) and relapse (N = 5) were evaluated by immunohistochemistry and immunofluorescence for EMT markers and Met status and these were correlated with patient outcome.
We identified that the activation of the Met receptor through HGF induced expression of mesenchymal markers, an aggressive phenotype, and chemoresistance. Blockade of this process with the Met inhibitor resensitized cells to chemotherapy in vitro and in vivo. Moreover, mesenchymal markers in human SCLC specimens were associated with Met activation, predicted worse survival, and were upregulated in chemorefractory disease.
These results provide novel evidence on an important role of Met-dependent EMT in the adverse clinical behavior of SCLC and support clinical trials of Met inhibitors and chemotherapy in this fatal disease.
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