Mutations in Bone Morphogenetic Protein (BMP) Receptor (BMPR)1A and SMAD4 are detected in 50% of juvenile polyposis syndrome (JPS) patients, who develop stroma-rich hamartomatous polyps. The... Show moreMutations in Bone Morphogenetic Protein (BMP) Receptor (BMPR)1A and SMAD4 are detected in 50% of juvenile polyposis syndrome (JPS) patients, who develop stroma-rich hamartomatous polyps. The established role of stromal cells in regulating BMP activity in the intestine implies a role for stromal cells in polyp development. We used conditional Cre-LoxP mice to investigate how specific loss of BMPR1A in endothelial cells, fibroblasts, or myofibroblasts/smooth muscle cells affects intestinal homeostasis. Selective loss of BMPR1A in fibroblasts causes severe histological changes in the intestines with a significant increase in stromal cell content and epithelial cell hyperproliferation, leading to numerous serrated polyps. This phenotype suggests that crucial changes occur in the fibroblast secretome that influences polyp development. Analyses of publicly available RNA expression databases identified CXCL12 as a potential candidate. RNAscope in situ hybridization showed an evident increase of Cxcl12-expressing fibroblasts. In vitro, stimulation of fibroblasts with BMPs resulted in downregulation of CXCL12, while inhibition of the BMP pathway resulted in gradual upregulation of CXCL12 over time. Moreover, neutralization of CXCL12 in vivo in the fibroblast-specific BMPR1A KO mice resulted in a significant decrease in polyp formation. Finally, in CRC patient specimens, mRNA-expression data showed that patients with high GREMLIN1 and CXCL12 expression had a significantly poorer overall survival. Significantly higher GREMLIN1, NOGGIN, and CXCL12 expression were detected in the Consensus Molecular Subtype 4 (CMS4) colorectal cancers, which are thought to arise from serrated polyps. Taken together, these data imply that fibroblast-specific BMP signaling-CXCL12 interaction could have a role in the etiology of serrated polyp formation. Show less
Quispel, W.T.; Stegehuis-Kamp, J.A.; Blijleven, L.; Santos, S.J.; Lourda, M.; Bos, C. van den; ... ; Egeler, R.M. 2016
Metastatic cancer is aggressive and rapidly developing, making it difficult to treat, often leading to mortality. Cancer cells are not isolated, but rather survive and proliferate in complex tumor...Show moreMetastatic cancer is aggressive and rapidly developing, making it difficult to treat, often leading to mortality. Cancer cells are not isolated, but rather survive and proliferate in complex tumor microenvironments. Importantly, tumor cells “educate” immune cells to play a supportive role during cancer progression. Therefore, understanding how cancer cells and immune cells communicate is of pivotal importance to limit tumor progression. In this project, we identified the chemokine receptor CXCR4 and its correspondent ligand, CXCL12, as a key couple that regulate the interaction between tumor cells and immune cells. The research has been performed using the zebrafish xenograft model. This model offers the advantage of looking at tumor-immune cell interaction on a single cell level and in a living whole organism. The transparency of the embryo and the current genetic tools available, in combination with the ease in pharmacological approaches, make this model an excellent tool to determine and impair cancer-microenvironment inter-communication. We showed that inhibiting the CXCL12-CXCR4 axis either on the tumor side or on the immune cell side leads to impaired tumor progression, during the early phases of metastasis formation. We propose that blocking cancer-stroma communication represents a promising therapeutic strategy to fight cancer.Show less
