Establishment of lung cancer cell line producing parathyroid hormone-related protein.

Parathyroid hormone-related protein (PTHrP) producing cell line (KCC-C1) was established from malignant pleural effusion of a patient with squamous cell lung carcinoma. Hypercalcemia and granulocytosis were noted in the patient. The serum level of PTHrP, measured by N-terminal specific radioimmunoassay, was 110 pg/ml (normal < 20 pg/ml). The established KCC-C1 tumor cells proved to have PTHrP RNA transcripts and produce a large amount of PTHrP. Besides the production of PTHrP, the culture medium contained a significant level of interleukin 1 (IL-1). However, tumor necrosis factor or colony stimulating factor was not defected. Transplantation of KCC-C1 tumor cells into nude mice resulted in tumor formation with hypercalcemia. As IL-1 is also known to have bone-resorbing activity, KCC-C1 which may prove valuable in the study of the interaction between PTHrP and IL-1 for induction of hypercalcemia.