JUN and cancer: It was demonstrated that JNK/c-Jun signaling activation by anisomycin could significantly increase PD-L1 expression in the parental cancer cells, while JNK/c-Jun signaling inhibition by SP600125 could markedly decrease PD-L1 expression in the drug-resistant cancer cells (Fig. 3e and f), which confirmed the crucial role of JNK/c-Jun signaling.