Establishment of a large cell lung cancer cell line (Y-ML-1B) producing granulocyte colony-stimulating factor.

We established a new lung cancer cell line, designated Y-ML-1B, from a lung cancer of a 70-year-old Japanese man with leukocytosis and thrombocytosis. Before surgical resection, the white blood cell and platelet counts were elevated to 34,400/mm3 and 668,000/mm3, respectively, and the granulocyte colony-stimulating factor (G-CSF) level in the serum was increased at 141 pg/mL. The primary tumor showed an undifferentiated morphology with large cells and induced extensive thickening of the pleura in the right hemithorax. The Y-ML-1B cells grow as a monolayer, with a doubling time of 19 hours, and are tumorigenic in nude mice, which showed a morphology similar to the primary tumor in xenografts. Analysis of the supernatant of cell culture medium of Y-ML-1B showed elevated levels of G-CSF and other cytokines such as interleukin (IL)-6, IL-8, and granulocyte-macrophage colony-stimulating factor (GM-CSF), consistent with the high levels detected in the patient's serum. Cytogenetic analysis revealed aneuploidy of greater than 56 in metaphases with many structural abnormalities. Mutation analysis of the tumor suppressor genes showed that Y-ML-1B is inactivated in TP53 and RASSF1A, but not in p14(ARF), p16(INK4A), or RB. Neither activating mutations of KRAS or NRAS nor amplification of MYC or MDM2 were detected. Y-ML-1B expressed N-cadherin but not E-cadherin. This newly established cell line might serve as a useful model for studying the molecular pathogenesis for large cell cancers of the lung which express high levels of cytokines.