Project description:In colorectal cancer, increased expression of the CXC chemokine receptor 4 (CXCR4) has been shown to provoke metastatic disease due to the interaction with its ligand stromal cell-derived factor 1 (SDF-1). Recently, a second SDF-1 receptor, CXCR7, was found to enhance tumor growth in solid tumors. Albeit signaling cascades via SDF-1/CXCR4 have been intensively studied, the significance of the SDF-1/CXCR7-induced intracellular communication triggering malignancy is still only marginally understood. In tumor tissue of 52 colorectal cancer (CRC) patients, we observed that expression of CXCR7 and CXCR4 increased with tumor stage, tumor size, and lymph node infiltration. Asking whether activation of CXCR4 or CXCR7 might result in a similar expression pattern, we performed microarray expression analyses using lentivirally CXCR4- and/or CXCR7-overexpressing SW480 colon cancer cell lines with and without stimulation by SDF-1α. Gene regulation via SDF-1α/CXCR4 and SDF-1α/CXCR7 was completely different and partly antidromic. Expressions of the differentially expressed genes AKR1C3, AXL, EGFR, IGFBP7, IL24, TNNC1, TRIP6 were confirmed by qPCR. Differentially regulated genes were assigned by GO to migration and lipid metabolic processes. Furthermore, using the in silico gene set enrichment analysis we showed for the first time that expressions of miR-217 and miR-218 were increased in CXCR4 and reduced in CXCR7 cells after stimulation with SDF-1α. As expected, their putative target mRNAs were inversely expressed. Functional assays exerted that exposure to SDF-1α resulted in strongly amplified invasiveness and chemosensitivity of CXCR4-expressing cells. CXCR7 overexpression led to reduced invasiveness which could only be marginally increased by SDF-1α. The CXCR4 antagonist plerixafor significantly reduced invasiveness of CXCR4-overexpressing cells only. Similarly, compared to control cells, CXCR4 cells showed increased sensitivity against 5-FU, while CXCR7 cells were more chemoresistant. These opposing results for CXCR4- or CXCR7-overexpressing colon carcinoma cells demand an unexpected attention in the clinical application of chemokine receptor antagonists like Plerixafor.

Project description:Recent studies have noted the tumor-stroma interaction as an integral part of tumor growth and spread as well as novel avenues for effective treatment. However, the details by which tumor and stroma cells communicate remain poorly understood. Here we show that the migration speed of the non-small-cell lung tumor cell line H838 is significantly increased under the influence of human pulmonary endothelial cells, HPAEC, in a transfilter co-culture system. To elucidate the effect of cell communication on the increased tumor cell migration, we record the H838 transcriptome response after the induction of migration in a hetero- and homogenous co-culture conditions. Gene Set enrichment analysis indicates a migration response of H838 in heterogenous co-culture system. Moreover, computationally transcription factor analysis relates the specific gene expression response to the cytokine-induced up-stream receptor activity and subsequently linking these factors to the upstream receptors via shortest paths across a directed protein-protein interaction network. This analysis predicted TNF- and SDF-1 signaling as well as multiple receptors upstream of Stat3 as putative mediators of the transcriptome response. To close the signaling information path from transcription factors to the possible receptor activation, we determine secretome quantification using a cytokine array. The latter revealed the predicted TNFa, SDF-1a signaling molecules as well as other known migration cytokines, like IL8 and IL6, as possible candidates for increased migration. Addition through the recombinant proteins or respected inhibitions reveal TNFa as well as SDF-1a as an immediate and early-late secreted factors that cause the increase in H838 migration. Interestingly, both factors were not regulated on the gene level of the H838 in heterogenous co-culture conditions, consequential HPAEC produce TNFa and SDF1a as shown by qPCR technique. Concluding, our combined computational and experimental approach revealed a holistic overview on the migration enhancement of lung tumor cells due to endothelial derived factors. Increase in migration is caused by an early TNFa induced inflammation response followed by a SDF-1a activity to sustaining the phenotype of migration. This tumor-endothelial-communication give a new insight for tumor migration.

Project description:In colorectal cancer, increased expression of the CXC chemokine receptor 4 (CXCR4) has been shown to provoke metastatic disease due to the interaction with its ligand stromal cell-derived factor 1 (SDF-1). Recently, a second SDF-1 receptor, CXCR7, was found to enhance tumor growth in solid tumors. Albeit signaling cascades via SDF-1/CXCR4 have been intensively studied, the significance of the SDF-1/CXCR7-induced intracellular communication triggering malignancy is still only marginally understood. In tumor tissue of 52 colorectal cancer (CRC) patients, we observed that expression of CXCR7 and CXCR4 increased with tumor stage, tumor size, and lymph node infiltration. Asking whether activation of CXCR4 or CXCR7 might result in a similar expression pattern, we performed microarray expression analyses using lentivirally CXCR4- and/or CXCR7-overexpressing SW480 colon cancer cell lines with and without stimulation by SDF-1M-NM-1. Gene regulation via SDF-1M-NM-1/CXCR4 and SDF-1M-NM-1/CXCR7 was completely different and partly antidromic. Expressions of the differentially expressed genes AKR1C3, AXL, EGFR, IGFBP7, IL24, TNNC1, TRIP6 were confirmed by qPCR. Differentially regulated genes were assigned by GO to migration and lipid metabolic processes. Furthermore, using the in silico gene set enrichment analysis we showed for the first time that expressions of miR-217 and miR-218 were increased in CXCR4 and reduced in CXCR7 cells after stimulation with SDF-1M-NM-1. As expected, their putative target mRNAs were inversely expressed. Functional assays exerted that exposure to SDF-1M-NM-1 resulted in strongly amplified invasiveness and chemosensitivity of CXCR4-expressing cells. CXCR7 overexpression led to reduced invasiveness which could only be marginally increased by SDF-1M-NM-1. The CXCR4 antagonist plerixafor significantly reduced invasiveness of CXCR4-overexpressing cells only. Similarly, compared to control cells, CXCR4 cells showed increased sensitivity against 5-FU, while CXCR7 cells were more chemoresistant. These opposing results for CXCR4- or CXCR7-overexpressing colon carcinoma cells demand an unexpected attention in the clinical application of chemokine receptor antagonists like Plerixafor. 24 samples

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