Integrated genomics-based approach to identify new therapeutic targets and cancer biomarkers for lung cancer.

Abstract

e13019 Background: Because the number of lung cancer patients who show good response to standard therapies is still limited, development of new anti-cancer agents with minimum risk of adverse effects and highly sensitive molecular biomarkers is urgently required. Methods: We have been screening novel therapeutic targets and their companion biomarkers for lung cancer as follows; i) To identify up-regulated genes in lung cancers by the gene microarray analysis, ii) To verify the candidate genes for their low expression in normal organs, iii) To validate the clinicopathological significance of their protein expression by tissue microarray covering hundreds of lung cancers, and iv) To verify their function for the growth of lung cancer cells by siRNAs. Results: We identified dozens of candidate oncoproteins and selected a serine/threonine kinase LASK2 (lung cancer-associated kinase 2). Immunohistochemical analysis showed that strong LASK2 positivity was an independent prognostic factor for non-small cell lung cancer patients (P < 0.0001). Suppression of LASK2 expression by its siRNAs inhibited proliferation of lung cancer cells. Introduction of LASK2 in mammalian cells also enhanced cellular growth in vitro and in mice model. Induction of LASK2 appeared to increase the levels of phosphorylation of oncogenic signal proteins for lung cancer. The data indicate that LASK2 is a prognostic biomarker and therapeutic target for lung cancers. Conclusions: Integrated genomics-based approach could facilitate the development of new cancer biomarkers as well as therapeutic targets for small molecules, monoclonal antibodies, nucleic acid drugs, and immunotherapies.