Establishment of a testicular carcinoma cell line producing alpha-fetoprotein

Objective To characterize a newly established human testicular carcinoma ce ll line that continuously produces alpha -fetoprotein (AFP), and to investi gate the effects of retinoic acid on AFP production. Materials and methods A 24-year-old man underwent a radical orchidectomy fo r a right testicular tumour and was found to have two separate metastatic l esions in the lungs, both of which were removed surgically. The cancer cell s were isolated from one of the tumours, which was composed of undifferenti ated germ cells and produced AFP; the cells were cultured in a monolayer. T his cell line was designated as KU-MT. Results The cell line was successfully maintained both in athymic nude mice and in culture. Histological examination showed that the xenografted tumou rs were composed of cells in the reticular, solid and glandular patterns of a yolk sac tumour, and of embryonal carcinoma cells. These cells immunosta ined positively for AFP. On electron microscopy, the extracellular depositi on of a basement lamina-like substance, a typical feature of yolk sac tumou r, was detected. The AFP production in mice correlated well with the tumour weight of the xenograft. The cultured KU-MT cells were oval to polygonal i n morphology and grew exponentially, with a population doubling time of app roximate to 2 days. Chromosomal analysis showed a modal number of 57 with c onsistent structural abnormalities of +add(1)(p13), del(1)(q32), del(2)(q31 ), add(6)(q21), +add(9)(p22), add(11)(p15), and add(14)(p11). Reverse-trans cription polymerase chain reaction analysis showed that the retinoic acid r eceptors (RAR)-alpha, RAR-gamma, and retinoid X receptor-alpha were present in the cells. The expression of AFP mRNA was up-regulated in response to a ll-trans-retinoic acid; treatment with this agent caused morphological chan ges and induced apoptosis in the cells. Conclusions This newly established cell line provides a reproducible model system that should offer a good insight into the differentiation of testicu lar carcinoma.