ANNULATE LAMELLAE IN A LARGE CELL LUNG-CARCINOMA CELL-LINE WITH HIGH EXPRESSION OF TYROSINE KINASE RECEPTOR AND PROTOONCOGENES

The morphology, karyotype, in vitro growth properties, and expression of tyrosine kinase receptors and proto-oncogenes are reported for a newly established large cell undifferentiated lung carcinoma cell line (RVH-6849). The results were analyzed concomitantly with those for two well established cell lines from an adenocarcinoma of the lung (A549) and a squamous cell carcinoma (A431). All three cell lines demonstrated common ultrastructural features of epithelial cells, but only RVH-6849 had frequent aggregates of centrioles and annulate lamellae (AL) and was polyploid, having five to seven copies of chromosome 7 by karyotype analysis. All three cell lines expressed transforming growth factor-alpha (TGF-alpha), epidermal growth factor receptor (EGFR), c-erb B-2, and c met genes. RVH-6849 cells, however, expressed the most messenger RNA (mRNA) for TGF-alpha, c-erb B-2, and c-met. Only EGFR mRNA was expressed more in the other two cell lines, especially in A431 cells-.AL represent an exaggerated form of the nuclear membrane pore complex that is found in actively proliferating cells such as germ and some neoplastic cells. AL are suspected to be involved in the deposition or processing of mRNA: The enhanced coexpression of AL and mRNAs of three tyrosine kinase containing receptors in RVH-6849 cells may represent such a relationship.