Abstract 4919: Myristoylated alanine-rich C kinase substrate (MARCKS) phosphorylation potentiates human lung cancer cell malignancy .

Abstract

Abstract Myristoylated alanine-rich C kinase substrate (MARCKS), a substrate of protein kinase C (PKC), is a key regulatory molecule controlling mucin secretion by airway epithelial cells in vitro and in vivo. Phosphorylated MARCKS (p-MARCKS) has been reportedly to promote inflammatory cell migration in several lung diseases. However, the functionality of MARCKS and its related phosphorylation in lung cancer malignancy has not been characterized. This study demonstrated MARCKS expression and elevated p-MARCKS in various lung cancer cell lines with high malignancy, such as CL1-0-F3, CL1-5, PC9, A549 and several tyrosine kinase inhibitor (TKI) resistant cell lines (H1650 and H1975), as compared with normal human bronchial epithelial (NHBE) cells and low metastasis cancer cell line. siRNA knockdown MARCKS expression resulted in an inhibition of cell migration, accompanying with a decrease of Slug expression in these malignant lung cancer cell lines. Treatment with myristoylated 24-amino-acid MARCKS N-terminus sequence (MANS) peptide, but not the control myristoylated random N-terminal sequence (RNS) peptide, suppressed MARCKS phosphorylation and impaired cell migration and wound healing ability in these lung cancer cell lines. Importantly, MANS peptide treatment resulted in a suppression of lamellipodia/filopodia formation and an enhancement of cell-cell contacts with increased E-cadherin expression. These results confirmed a crucial role for MARCKS, specifically its phosphorylation, in potentiating lung cancer cell migration and malignancy. This study has also suggested a potential usage of MANS or the MARCKS-related peptides in the treatment of lung cancer metastasis. Citation Format: Ching-Hsien Chen, Phillip Thai, Reen Wu. Myristoylated alanine-rich C kinase substrate (MARCKS) phosphorylation potentiates human lung cancer cell malignancy . [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4919. doi:10.1158/1538-7445.AM2013-4919