Suppression Of Lung Cancer Malignancy By Peptides Targeting Marcks Phosphorylation Site Domain: A Comparative Study

We have recently reported elevated MARCKS phosphorylation (p-MARCKS) in lung cancer tissues but not in their adjacent normal non-cancer tissue sections. We have extended this study to a tumor tissue array from a cohort of 110 human patients with lung cancer. Immunohistochemistry results have shown a significant association of elevated p-MARCKS with advanced-stage, lymph node metastasis and malignant phenotypes of lung cancer, confirming the importance of p-MARCKS in lung cancer progression. To see if this newly discover biomarker can be a target for therapeutic treatment for the suppression of lung cancer malignancy, we have employed two peptides for this potential; one is the MANS peptide developed by our collaborator many years ago to target myristoylated N-terminal amino acid region for the control of airway mucus granule secretion, the other peptide is MPS that directly targets the MARCKS phosphorylation site domain. For MANS peptide, our recent publication has shown it is effective in blocking lung cancer cell migration and invasiveness in vitro as well as in vivo metastasis. A similar observation was seen for MPS peptide treatment. However, in contrast to MANS peptide, MPS treatment can directly block PIP3-dependent AKT signaling and repress lung tumor growth in vivo in addition to the suppression of metastasis, while MANS can only reduce cancer metastasis. These results support the initial notion on the involvement of p-MARCKS as a biomarker in lung cancer and the potential to target the phosphorylation site domain for controlling cancer progression. Our data have also suggested a direct targeting MARCKS phosphorylation site domain by MPS peptide is more effective in the suppression of lung cancer malignancy. Citation Format: Ching-Hsien Chen, Sarah Statt, Phillip Thai, Jasmine G. Lee, Kenneth B. Adler, Pan-Chyr Yang, Reen Wu. Suppression of lung cancer malignancy by peptides targeting MARCKS phosphorylation site domain: A comparative study. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2596. doi:10.1158/1538-7445.AM2014-2596