TRERF1 and renal carcinoma: In contrast, in 786-0 renal cancer cells (where c-Met is over-expressed and can induce PD-L1), Honokiol decreased the basal PD-L1 expression, while RAPA alone did not mediate any significant change; however, the combination of RAPA and Honokiol markedly down-regulated the basal PD-L1 (Figure 6B).