GIT1 promotes lung cancer cell metastasis through modulating Rac1/Cdc42 activity and is associated with poor prognosis

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// Jeng-Shou Chang 1, 2 , Chia-Yi Su 2 , Wen-Hsuan Yu 3, 4 , Wei-Jiunn Lee 5, 6 , Yu-Peng Liu 7 , Tsung-Ching Lai 2 , Yi-Hua Jan 2 , Yi-Fang Yang 2 , Chia-Ning Shen 2 , Jin-Yuh Shew 2 , Jean Lu 2 , Chih-Jen Yang 8 , Ming-Shyan Huang 8 , Pei-Jung Lu 9 , Yuan-Feng Lin 10 , Min-Liang Kuo 11 , Kuo-Tai Hua 12 , Michael Hsiao 2 1 Institute of Biochemistry and Molecular Biology, National Yang-Ming University, Taipei, Taiwan 2 Medical Biology, Genomics Research Center, Academia Sinica, Taipei, Taiwan 3 Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA 4 Graduate School of Biomedical Sciences, The University of Texas Houston Health Science Center, Houston, Texas, USA 5 Department of Urology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan 6 Department of Medical Education and Research, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan 7 Institute of Genomic Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan 8 Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan 9 Institute of Clinical Medicine, Medical College, National Cheng Kung University, Tainan, Taiwan 10 Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan 11 Institute of Biochemical Science, National Taiwan University College of Life Science, Taipei, Taiwan 12 Graduate Institute of Toxicology, National Taiwan University College of Medicine, Taipei, Taiwan Correspondence to: Michael Hsiao, e-mail: mhsiao@gate.sinica.edu.tw Kuo-Tai Hua, e-mail: kthua@ntu.edu.tw Keywords: GIT1, Rac1/Cdc42, Rho GTPases, metastasis, lung cancer prognosis Received: April 17, 2015 Accepted: September 28, 2015 Published: October 08, 2015 ABSTRACT G-protein-coupled receptor kinase interacting protein 1 (GIT1) is participated in cell movement activation, which is a fundamental process during tissue development and cancer progression. GIT1/PIX forming a functional protein complex that contributes to Rac1/Cdc42 activation, resulting in increasing cell mobility. Although the importance of Rac1/Cdc42 activation is well documented in cancer aggressiveness, the clinical importance of GIT1 remains largely unknown. Here, we investigated the clinical significance of GIT1 expression in non-small-cell lung cancer (NSCLC) and also verified the importance of GIT1-Rac1/Cdc42 axis in stimulating NSCLC cell mobility. The result indicated higher GIT1 expression patients had significantly poorer prognoses in disease-free survival (DFS) and overall survival (OS) compared with lower GIT1 expression patients. Higher GIT1 expression was an independent prognostic factor by multivariate analysis and associated with migration/invasion of NSCLC cells in transwell assay. In vivo studies indicated that GIT1 promotes metastasis of NSCLC cells. Finally, GIT1 was found to stimulate migration/invasion by altering the activity of Rac1/Cdc42 in NSCLC cells. Together, the GIT1 expression is associated with poor prognosis in patients with NSCLC. GIT1 is critical for the invasiveness of NSCLC cells through stimulating the activity of Rac1/Cdc42.