Establishment and characterization of a human ovarian small cell carcinoma, hypercalcemic type, cell line (OS-1) secreting PTH, PthrP and ACTH--special reference to the susceptibility of anti-cancer drugs.

We successfully established a novel cell line (OS-1) derived from human ovarian small cell carcinoma, hypercalcemic type secreted PTH, PTH-rP and ACTH. The OS-1 cell line was established from metastatic focus of uterus. A patient was 25-year-old Japanese woman. The first she received left ovariectomy on April 2002. The histopathological diagnosis was ovarian small cell carcinoma, pT2c, Nx, Mx. Then on June 2003, metastatic focus of uterus was ectomied. A part of the recurrent tumor of uterus was cut into small pieces with razor blades, and dissociated with 0.1% trypsin-0.02% EDTA/ PBS(-) solution at room temperature. The single cells and small cell clusters were seeded into 60mm dishes and cultured in growth medium (GM: DMEM/F12 supplemented with 20% fetal bovine serum and 0.1% non-essential amino acids solution) at 37 degrees C, 4.7% CO2 in humidified air. Medium was exchanged twice a week. The OS-1 cells grew as floating cultures in the dishes. Radioimmunoassay of the conditioned media was revealed that the cultures secreted large amount of PTH, PTHrP and ACTH simultaneously. Susceptibilities of anti-cancer drugs to the OS-1 cells were examined using oxygen electrode meter (Daikin), and the results suggested VLB and TXL were effective, and CDDP, CPT-11, VP-16, VCR, CPA, MMC and CBDCA were not effective. In our knowledge, it is the first report that the cell line secreting PTH, PTHrP and ACTH was successfully established from ovarian small cell carcinoma, hypercalcemic type. We expect that OS-1 cell line contribute to study on the mechanism of ectopic hormone secretion and susceptibility of anti cancer drugs to the small cell carcinoma.