Proteomics Analysis Of The TGF-beta Response Program In GBM Cells

TGF-beta Plays an essential role in maintaining tissue homeostasis through its ability to induce cell cycle arrest, differentiation, apoptosis, and to preserve genomic stablity.Thus, TGF-beta is a potent anticancer agent that prohibits the uncontrolled proliferation of epithelial, endothelial and hematopoietic cells. Interestingly, tumorigenesis typically elicits aberrations in TGF-beta signaling pathway that engenders resistance to the cytostatic activities of TGF-beta, thereby enhancing the development and progression of human malignancies. Moreover, these genetic and epigenetic events conspire to convert TGF-beta from a suppressor of tumor formation to a promoter of their growth, invasion and metastasis. TGF-beta regulates tumorigenesis and its signaling pathways are often modified during tumor progressionin human cancers, such as Glioblastoma (GBM), which is the most common and most aggressive malignant primary brain tumor in human. Prior to initiation and early during progression TGF-beta acts as a tumor suppressor, however, at later stage it is often a tumor promoter. The dichotomous nature of TGF-beta during tumorigenesis is known as its paradox.Here, we focus on the potential role of TGF-betal in Glioblastoma, and proteomics analysis of the TGF-beta response in GBM cells by a novel method: Triple-SILAC. We have developed an efficient workflow by combining this method and other traditional molecular methods. The applicability of some new methods in this workflow was proved. The intracellular proteins and extracellular matrix proteins from GBM cell line M059J were extracted for SILAC experiments separately. As results,2771 intracellular proteins and 471 extracellular matrix proteins were identified by MS/MS. Within these proteins,255 intracellular proteins and 93 extracellular matrix proteins with significant differential expression between the GBM samples of TGF-betal+/-treatment were found by SILAC, which might be associated with TGF-beta response in GBM cells. Furthermore, the quantitative change of mRNA for 19 proteins chosed from those 348 proteins was validated by qPCR. In conclusion, our results provide a valuable protomics dataset for understanding TGF-beta pathway in glioblastoma cancer.