Establishment and characterization of an immortalized human sebaceous gland cell line (SZ95)

Human facial sebaceous gland cells were transfected with a PBR-322-based pl asmid containing the coding region for the Simian virus-40 large T antigen, The resulting proliferating cell cultures have been passaged over 50 times to date, have been cloned, and show no signs of senescence after 4 1/2 y i n vitro, whereas normal human sebocytes can only be grown for three to six passages, The immortalized transfected cells, termed SZ95, expressed the Si mian virus-40 large T antigen and presented an hyperdiploid-aneuploid karyo type with a modal chromosome number of 64.5. The SZ95 cell line exhibited e pithelial, polymorphous characteristics with different cell sizes of up to 3.25-fold during proliferation and 6-fold at confluence, showing numerous c ytoplasmic lipid droplets. The cells showed large cytoplasm profiles with a bundant organelles, including vacuoles and myelin figures which indicated l ipid synthesis, Lack of or only few desmosomal areas were observed, SZ95 ce lls expressed molecules typically associated with human sebocytes, such as keratins 7, 13, and 19, and several proteins of the polymorphous epithelial mucin family, Functional studies revealed synthesis of the sebaceous lipid s squalene and wax esters as well as of triglycerides and free fatty acids, even after 25-40 passages; active lipid secretion; population doubling tim es of 52.4 +/- 1.6 h; reduced growth but maintenance of lipid synthesis und er serum-free conditions; and retrieval of cell proliferation after additio n of 5 alpha-dihydrotestosterone, Retinoids significantly inhibited prolife ration of certain SZ95 cell clones in the expected magnitude 13-cis-retinoi c acid > au-tuans-retinoic acid>>acitretin, Thus SZ95 is an immortalized hu man sebaceous gland cell line that shows the morphologic, phenotypic and fu nctional characteristics of normal human sebocytes.