ABSTRACT
Identifying novel targets that control both tumorigenesis and angiogenesis can aid in developing a more potent anti-angiogenic therapeutic strategy. We previously reported that reduction of FRG1 is associated with increased p38-MAPK signaling in prostate cancer and with elevated MEK-ERK signaling in breast cancer. Here, we reveal the role of FRG1 in tumor angiogenesis. Our findings demonstrate that depleted FRG1 levels enhance the proliferation, migration, and tubule formation of HUVECs in a paracrine manner, and this was further substantiated in multiple animal models. Mechanistically, FRG1 depletion activated the expression of FGF2 in breast cancer cells, which triggered the ERK/AKT cascade in endothelial cells. As FRG1 affects multiple tumorigenic properties and it is upstream of FGF2, it can be explored as a therapeutic target that is less prone to resistance.
Subject(s)
Fibroblast Growth Factor 2 , Proto-Oncogene Proteins c-akt , Animals , Male , Carcinogenesis/metabolism , Endothelial Cells/metabolism , Fibroblast Growth Factor 2/metabolism , MAP Kinase Signaling System , Proto-Oncogene Proteins c-akt/metabolism , Signal Transduction , RNA-Binding Proteins/metabolism , Microfilament Proteins/metabolismABSTRACT
The chick chorioallantoic membrane (CAM) is an extra-embryonic membrane, comprised of a high density of blood and lymphatic vessels. CAM has a dense capillary network and is commonly used to study in vivo angiogenesis and anti-angiogenesis in response to potential biomolecules and drugs. Most of the earlier reported CAM assays described the in-ovo method-where the viability of the embryo is higher, but accessibility to the CAM is limited. Ex-ovo CAM methods were previously described that employed shell-less cultures of chick embryos, but the low viability of embryos reduced the overall robustness of the angiogenesis assays. We described a method (named as cup-CAM method) which is more economical, has better accessibility and has significantly improved the viability of the embryo till advanced developmental stages. We could perform this simple yet useful experimentation with the common tools available in the laboratory. We successfully used the cup-CAM method for showing the paracrine effects of conditioned media from tumor cells, on the angiogenesis. This method can be used to assay the angiogenic potential of a drug or protein and to observe the embryonic development of the chick embryo and other related scientific applications.
