Development of new transformants of mouse JB6P series cells as tools for understanding redox and transcriptional factor regulation

4269 The mouse epidermal JB6P cell line consists of tumor promotion sensitive (JB6P+) and tumor promotion resistant cells (JB6P-) that have been widely utilized to study tumor promotion. We transformed the JB6P+ cell line with prolonged low dose, UVBR (10mJ/cm 2 ), H 2 O 2 (10µM), and CdCl 2 (1µg/ml). Cell transformation was confirmed by anchorage-independence. JB6P+ parent cells formed colonies in soft agar culture (13.7±3.5 per 20 high-power fields) which are increased by stimulation with the tumor promotor TPA (44.7±2.9). For the new transformants in the absence of TPA, colonies formed (104.0± 17.3 per 20 high-power fields, JB6P+/UV; 56.7±15.0, JB6P+/H 2 O 2 ; 64.3±22, JB6P+/Cd cells; p 2 O 2 (6.5, 1.3-fold), and JB6P+/Cd cells (3.6,1.4 fold). Many nuclear transcription factors, for example Activating Protein-1(AP-1), are rapidly activated by elevated ROS stresses. Using Western Blot analysis of nuclear protein extractions, the distinct AP-1 composition patterns are summarized in the table below. We hypothesize that the UVBR, H 2 O 2 and CdCl 2 transformed the JB6P+ cells through different mechanisms. Relative l densitometric laser measurements of AP-1 subunits Each band was scanned and the densitometric measurements normalized to the JB6P+ results. ( C-Fos was normalized to JB6P+/UV results). * The zero value represents