DEVELOPMENT AND ELONGATION OF NEURITE-LIKE OUTGROWTH ON SMALL-CELL LUNG-CANCER CELL-LINES

One (Lu-134A) of nine human small cell lung cancer cell lines which gr ow as Boating cell aggregates changed its morphology dramatically when cells Here cultured on a coverslip coated with polyethylenimine or ex tracellular matrix of human lung adenocarcinoma cell line PC-9 cells. The Lu-134A cells adhered to the substrate and developed elongated cyt oplasmic processes which gradually grew into long neuronal-like proces ses. These processes developed to a length of more than 10 times the c ell body length after 20 days of culture. Addition of dibutyryl cyclic adenosine 3', 5'-monophosphate to the cells on these substrates remar kably promoted the development and elongation of the precesses, which grew into a netlike arrangement. The characteristics of these elongate d neuronal-like processes were studied using immunocytochemical and el ectron microscopical methods. The processes reacted intensely with mon oclonal antibodies against beta-tubulin and microtubule-associated pro tein-2. The swelling portions of the distal tips of these processes re acted strongly with polyclonal antibody against synaptophysin. Neurose cretory granules and bundles of microtubules were observed within proc esses. These findings suggested that this human small cell lung cancer cell line (Lu-134A) differentiated into neuronal cells, and indicated that attachment of cells to a substrate is the key to the development of long neurite-like outgrowths.