ATRA resistant CRL-2151 cells did not show changes in Chmp1A, P53 or phospho-P53 upon ATRA treatment but showed growth inhibition and an increase in the expression of these proteins upon Chmp1A over-expression. (A) CRL-2151 cells were counted and equal numbers of cells were seeded in 10 cm tissue culture dishes. Next day cells were treated with control DMSO or ATRA. The following 4 days, cells were counted and plotted for the graph. Black line with circle represents DMSO treated and gray line with square represents ATRA treated. Notice that there is no significant change in growth between DMSO and ATRA treated cells. (B) The cells were processed for Western blot analysis following lysis. Chmp1A, P53 and phospho-P53 protein expression showed no difference with DMSO or ATRA treated cells. Gapdh indicates the equal loading of samples. (C-E) Growth was inhibited a day after transfection with Chmp1A compared to control (C). The expression of Chmp1A, P53 and phospho-P53 (at serine 15 and 37) was increased a day after transfection with Chmp1A compare with control (D). Densitometric analysis was performed and the change of protein level was determined by setting control as "1" after corrected for Gapdh (E).