EVALUATION OF THE TETRACYCLINE-REPRESSIBLE TRANSACTIVATOR SYSTEM FOR INDUCIBLE GENE-EXPRESSION IN HUMAN PROSTATE-CANCER CELL-LINES

BACKGROUND. Studies of genes that may inhibit growth or induce death o f cells are facilitated greatly by tightly controlled expression of th ose genes. A promising system for control of transgene expression over a wide range is the tetracycline-repressible transactivator (tTA) sys tem developed by Gossen and Bujard [Proc Natl Acad Sci USA 1992;89:554 7-5551]. We investigated the effectiveness of this system in three wel l-established human prostate cancer cell lines. METHODS. LNCaP, PC-3, and Tsu-Pr1 cells were transfected with a vector coding for the tTA pr otein and/or a luciferase reporter vector, and luciferase activity was measured in the presence and absence of tetracycline or the tTA prote in. RESULTS. Ln the absence of tetracycline, the tTA system yielded hi gh levels of luciferase activity in all three cell lines. Background l uciferase activity in the presence of tetracycline was nearly undetect able in LNCaP cells, moderate in Tsu-Pr1 cells, and more than 20-fold higher in PC-3 than in Tsu-Pr1 cells. Similar background activity was observed in Tsu-Prl and PC-3 cells, even in the absence of the transac tivator protein. CONCLUSIONS. The tTA system should be useful for stab le transfection of cytotoxic transgenes in LNCaP cells and for control of transgene expression over a wide range in Tsu-Pr1 and PC-3 cells. (C) 1997 Wiley-Liss, Inc.