PTBP1 enhances exon11a skipping in Mena pre-mRNA to promote migration and invasion in lung carcinoma cells.

Abstract

Alternative splicing (AS) events occur in the majority of human genes. AS in a single gene can give rise to different functions among multiple isoforms. Human ortholog of mammalian enabled (Mena) is a conserved regulator of actin dynamics that plays an important role in metastasis. Mena has been shown to have multiple splice variants in human tumor cells due to AS. However, the mechanism mediated Mena AS has not been elucidated. Here we showed that polypyrimidine tract-binding protein 1 (PTBP1) could modulate Mena AS. First, PTBP1 levels were elevated in metastatic lung cancer cells as well as during epithelial-mesenchymal transition (EMT) process. Then, knockdown of PTBP1 using shRNA inhibited migration and invasion of lung carcinoma cells and decreased the Mena exon11a skipping, whereas overexpression of PTBP1 had the opposite effects. The results of RNA pull-down assays and mutation analyses demonstrated that PTBP1 functionally targeted and physically interacted with polypyrimidine sequences on both upstream intron11 (TTTTCCCCTT) and downstream intron11a (TTTTTTTTTCTTT). In addition, the results of migration and invasion assays as well as detection of filopodia revealed that the effect of PTBP1 was reversed by knockdown of Mena but not Mena11a+. Overexpressed MenaΔ11a also rescued the PTBP1-induced migration and invasion. Taken together, our study provides a novel mechanism that PTBP1 modulates Mena exon11a skipping, and indicates that PTBP1 depends on the level of Mena11a- to promote lung cancer cells migration and invasion. The regulation of Mena AS may be a potential prognostic marker and a promising target for treatment of lung carcinoma.

• Authors: Shuaiguang Li, Lianghua Shen, Luyuan Huang, Sijia Lei, Xingdong Cai, Mason Breitzig, Bin Zhang, Annan Yang, Wenzuo Ji, Meiyan Huang, Qing Zheng, Hanxiao Sun, Feng Wang
• Journal: Biochimica et biophysica acta. Gene regulatory mechanisms (Biochim Biophys Acta Gene Regul Mech) Vol. 1862 Issue 8 Pg. 858-869 (08 2019) ISSN: 1876-4320 [Electronic] Netherlands
• PMID: 31075540 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2019 Elsevier B.V. All rights reserved.

Chemical References

• Enah protein, human
• Heterogeneous-Nuclear Ribonucleoproteins
• Microfilament Proteins
• PTBP1 protein, human
• Polypyrimidine Tract-Binding Protein

Topics

• A549 Cells
• Alternative Splicing
• Cell Movement
• Epithelial-Mesenchymal Transition
• Exons
• Gene Expression Regulation, Neoplastic
• Heterogeneous-Nuclear Ribonucleoproteins (genetics, metabolism)
• Humans
• Lung Neoplasms (genetics, metabolism)
• Microfilament Proteins (genetics)
• Neoplasm Invasiveness
• Polypyrimidine Tract-Binding Protein (genetics, metabolism)
• Up-Regulation