Cyst-derived cells do not exhibit accelerated growth or features of transformed cells in vitro.

Progressive renal enlargement is a prominent feature in autosomal dominant polycystic kidney disease (ADPKD), suggesting that the disease is due to hyperplasia and/or preneoplastic transformation of renal epithelial cells. In this study in vitro methods were developed to grow and propagate large numbers of cyst-derived epithelial cells from ADPKD kidneys and cortical epithelial cells from normal human kidneys (NK). In order to study their biologic features during early cell passages, cells were grown on Vitrogen (bovine dermal collagen)-FCS (fetal calf serum) coated dishes and fed a basic medium (DME:F12) supplemented with 10% FCS or a defined medium (Sens) containing insulin, transferrin, selenium, hydrocortisone, tri-iodothyronine and epidermal growth factor (EGF). Both ADPKD and NK cells grew as monolayers, were positive for keratin by immunohistochemistry and flow cytometry and had ultrastructural features of renal epithelial cells. Confluent NK and ADPKD monolayers formed domes. In contrast to NK cells, the growth and propagation of ADPKD cells were not supported by defined medium alone but required serum supplementation and ADPKD cells did not respond to growth factors (insulin, transferrin, EGF) that promoted the growth of NK cells. In serum supplemented media, the growth rate, cell doubling time and end cell number of ADPKD and NK cells were the same. Moreover, ADPKD cells did not exhibit any in vitro features of transformed cells: they were not immortal, they were sensitive to contact inhibition, they were anchorage dependent and they were not tumorigenic in nude mice. These findings do not support an increased rate of cell growth or cell transformation as causative factors in ADPKD.