Identification of Genes (SPON2 and C20orf2) Differentially Expressed between Cancerous and Noncancerous Lung Cells by mRNA Differential Display

Abstract

mRNA differential display was applied to three small cell lung carcinoma (SCLC) cell lines, six non-small cell lung carcinoma (NSCLC) cell lines, and three normal lung tissues to identify genes differentially expressed between lung carcinoma cells and normal lung tissues and between SCLC cells and NSCLC cells. We isolated five differentially expressed genes, two that were novel and three that were already known. DIL-1 (differentially expressed in cancerous and noncancerous lung cells; HGMW-approved symbol SPON2) and pulmonary surfactant apoprotein A were expressed in normal lung tissues but not in lung carcinoma cell lines, whereas DIL-2 (HGMW-approved symbol C20orf2) and nm23-H1 were expressed in lung carcinoma cell lines but not in normal lung tissues. The remaining gene, Annexin II, was expressed at a lower level in SCLC than in NSCLC and normal lung tissues. These genes were also differentially expressed in primary lung cancers. One of the two novel genes, DIL-1, encodes a secreted protein homologous to the Mindin/F-spondin family. The other, DIL-2, encodes a protein with a putative ATP/GTP binding site motif. These data provide basic information necessary to understand the differences in gene expression profiles between lung carcinoma and normal lung and between SCLC and NSCLC. Further characterization of these genes will help to clarify the molecular mechanisms of human lung carcinogenesis.