Overexpression of PP2A inhibitor SET oncoprotein is associated with tumor progression and poor prognosis in human non-small cell lung cancer.

Abstract

SET oncoprotein is an endogenous inhibitor of protein phosphatase 2A (PP2A), and SET-mediated PP2A inhibition is an important regulatory mechanism for promoting cancer initiation and progression of several types of human leukemia disease. However, its potential relevance in solid tumors as non-small cell lung cancer (NSCLC) remains mostly unknown. In this study, we showed that SET was evidently overexpressed in human NSCLC cell lines and NSCLC tissues. Clinicopathologic analysis showed that SET expression was significantly correlated with clinical stage (p < 0.001), and lymph node metastasis (p < 0.05). Kaplan-Meier analysis revealed that patients with high SET expression had poorer overall survival rates than those with low SET expression. Moreover, knockdown of SET in NSCLC cells resulted in attenuated proliferative and invasive abilities. The biological effect of SET on proliferation and invasion was mediated by the inhibition of the PP2A, which in turn, activation of AKT and ERK, increased the expression of cyclin D1 and MMP9, and decreased the expression of p27. Furthermore, we observed that restoration of PP2A using SET antagonist FTY720 impaired proliferative and invasive potential in vitro, as well as inhibited tumor growth in vivo of NSCLC cells. Taken together, SET oncoprotein plays an important role in NSCLC progression, which could serve as a potential prognosis marker and a novel therapeutic target for NSCLC patients.

• Authors: Hao Liu, Yixue Gu, Hongsheng Wang, Jiang Yin, Guopei Zheng, Zhijie Zhang, Minyin Lu, Chenkun Wang, Zhimin He
• Journal: Oncotarget (Oncotarget) Vol. 6 Issue 17 Pg. 14913-25 (Jun 20 2015) ISSN: 1949-2553 [Electronic] United States
• PMID: 25945834 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• DNA-Binding Proteins
• Histone Chaperones
• SET protein, human
• Transcription Factors
• Cyclin D1
• Cyclin-Dependent Kinase Inhibitor p27
• Proto-Oncogene Proteins c-akt
• Extracellular Signal-Regulated MAP Kinases
• Protein Phosphatase 2
• Matrix Metalloproteinase 9
• Fingolimod Hydrochloride

Topics

• Animals
• Blotting, Western
• Carcinoma, Non-Small-Cell Lung (genetics, metabolism, pathology)
• Cell Line, Tumor
• Cell Proliferation (drug effects, genetics)
• Cyclin D1 (metabolism)
• Cyclin-Dependent Kinase Inhibitor p27 (metabolism)
• DNA-Binding Proteins
• Disease Progression
• Extracellular Signal-Regulated MAP Kinases (metabolism)
• Fingolimod Hydrochloride (pharmacology)
• Histone Chaperones (genetics, metabolism)
• Humans
• Kaplan-Meier Estimate
• Lung Neoplasms (genetics, metabolism, pathology)
• Lymphatic Metastasis
• Matrix Metalloproteinase 9 (metabolism)
• Mice
• Neoplasm Staging
• Prognosis
• Protein Phosphatase 2 (genetics, metabolism)
• Proto-Oncogene Proteins c-akt (metabolism)
• RNA Interference
• Reverse Transcriptase Polymerase Chain Reaction
• Transcription Factors (genetics, metabolism)
• Transplantation, Heterologous