307 Transgelin Regulates Colon Cancer Cell Invasion by Interacting With PARP1 and Activating Rho Signaling Pathway: A Bioinformatics Analysis

Abstract

INTRODUCTION: Our previous studies found that Transgelin was up-regulated in node-positive colorectal cancer versus in node-negative disease. Transgelin, an actin-binding protein, is associated with the remodeling of cytoskeleton in the cytoplasm. However, we found that Transgelin had nuclear localization in colon cancer cells and gene expression profiling identified that TAGLN over-expression affected the expression of 256 downstream genes closely related to cell morphology, migration and invasion. In addition, we found that Transgelin could interact with 297 proteins by immunoprecipitation and liquid chromatography -mass spectrometry. Thus, we speculate that Transgelin may play different roles in the nucleus and the cytoplasm, which collaboratively participate in the invasion and metastasis of colon cancer cells. METHODS: 256 downstream genes regulated by Transgelin were analyzed by bioinformatics analysis. Transgelin has been found to regulate colon cancer metastasis through specific key genes and signaling pathways. Then, by analyzing the promoter regions of these key genes, a protein has been predicted to be the transcription factor of these genes. Further, by comparing the 297 proteins that have been previously detected to potentially interact with Transgelin, we found that the predicted transcription factor fell in this pool. Finally, we verified the interaction between Transgelin and this transcription factor by immunoprecipitation and Western blotting. RESULTS: Over-expression of TAGLN could lead to differential expression of 184 downstream genes. By constructing the network of gene-encoded proteins, we conducted network topology analysis and identified the key genes, including CALM1, MYO1F, NCKIPSD, PLK4, RAC1, WAS and WIPF1 (Figure 1). They are mainly involved in the Rho signaling pathway which is related to oncogenesis and tumor metastasis. In addition, bioinformatics analysis (GCBI tools) showed that all of the promoter regions of the key genes had binding sites with PARP1 protein. And PARP1 also fell in the 297 proteins that have been previously detected to interact with Transgelin. Thus, PARP1 protein was selected as a potential transcription factor. Immunoprecipitation validated that PARP1 interacted with Transgelin in RKO human colon cancer cells. CONCLUSION: Bioinformatics analysis revealed that Transgelin may activate the Rho signaling pathway in promoting colon cancer metastasis by interacting with PARP1.