Finally, we show that increased levels of CK-B seen in SCLC are not accompanied by gene amplification or rearrangement, but reflect a greatly enhanced level of CK-B specific mRNA that is not seen in non-SCLC lines thus far examined.
After multiple passages, UMC-SCLC-1 gradually changed its culture characteristics to a cell line, UMC-SCLC-1A, with morphological features of large cell anaplastic carcinoma, an altered growth pattern, decrease in calcitonin, and increase in radioresistance but retained the other biochemical markers of classic SCLC (bombesin and dopa decarboxylase production).
Four neuroblastoma (LA-N-5, SH-SY5Y, Paju, and SK-N-MC) and three small-cell lung carcinoma (U-2020, U-1690, and U-1285) cell lines were selected on the basis of their stage of neurocrine differentiation, as determined by the expression of neuron-specific enolase.
They both expressed high concentrations of the SCLC marker enzymes neuron-specific enolase and the creatine kinase isoenzyme BB and showed no significant differences in their chromosomal characteristics. c-myc was amplified and expressed in both cell lines, and SCLC-21H had an additional rearranged and amplified EcoRI c-myc fragment.
They both expressed high concentrations of the SCLC marker enzymes neuron-specific enolase and the creatine kinase isoenzyme BB and showed no significant differences in their chromosomal characteristics. c-myc was amplified and expressed in both cell lines, and SCLC-21H had an additional rearranged and amplified EcoRI c-myc fragment.
Both UMC-SCLC-1 and UMC-SCLC-1A demonstrated the deletion of chromosome 3p, amplification and abundant expression of N-myc, and increased expression of c-raf.
Furthermore, karyotype analysis revealed that SCLC cell lines Lu134 and H69 contained a morphologically normal chromosome 7, which carries the EGF receptor gene.
After multiple passages, UMC-SCLC-1 gradually changed its culture characteristics to a cell line, UMC-SCLC-1A, with morphological features of large cell anaplastic carcinoma, an altered growth pattern, decrease in calcitonin, and increase in radioresistance but retained the other biochemical markers of classic SCLC (bombesin and dopa decarboxylase production).
After multiple passages, UMC-SCLC-1 gradually changed its culture characteristics to a cell line, UMC-SCLC-1A, with morphological features of large cell anaplastic carcinoma, an altered growth pattern, decrease in calcitonin, and increase in radioresistance but retained the other biochemical markers of classic SCLC (bombesin and dopa decarboxylase production).
Although the biomarkers L-Dopa decarboxylase, bombesin, carcinoembryonic antigen, and neurotensin were detectable in SCLC-22H, they were undetectable or low in SCLC-21H.
We analyzed in detail the structure of the L-myc gene isolated from human placental DNA and characterized its expression in several small-cell lung cancer cell lines.