Fig. 3. TLN468 restores p53-R231X activity. ( A ) Human H1299 (p53 −/− ) cells were cotransfected with pCMV-R213X, pCMV-LacZ, and p53BS-luc. The pCMV-R213X vector expresses the P53 gene with the nonsense R213X mutation. The p53BS-luc vector expresses the luciferase gene under the control of a p53-dependent promoter, leading to the detection of a transcriptionally active p53. The pCMVLacZ vector was used for normalization. ( B ) HDQ-P1 cells were left untreated or were treated with TLN468 (80 μM) for 48 h. mRNA levels for Bax, one of the major targets of p53, were determined by qRT-PCR ( n  = 3). The results are expressed relative to the normalized relative amount of mRNA in the absence of treatment, set to 1.