PLPP1 and lung cancer: To investigate whether PLPP1 participated in the effect of Z-ligustilide+cisplatin on the resistance of cisplatin-resistant lung cancer cells, we knocked down the expression of PLPP1 in A549/DDP and H460/DDP cells, and the mRNA level and protein expression of PLPP1 were examined using real-time PCR and Western blot analysis (Figure S3 and Figure 5A).