Effect of THC on p53 protein expression. CEM and HL60 cells were cultured with an IC₅₀ concentration (day 2), and p53 expression was assessed by immunoblot analysis at 6, 24, and 48 hours (A). Similarly, culturing MOLT-4 cells with THC for 2 days also showed no increase in p53 levels, while culturing with cisplatin (cddp) did (B). The culture of CEM cells with THC at 1 × and 5 × IC₅₀ resulted in duration-independent increases in cleaved PARP and decreases in phosphorylated-pERK (C).