**Figure 6.** **Signaling pathways involved in low-CPT1C-expression-induced senescence in vector PANC-1 cells and regulation of the TP53 signaling pathway on CPT1C.** (**A**) Quantitative RT-PCR analysis for suppressed genes in senescent vector PANC-1 cells. Data are presented as the mean ± S.E.M, n = 3 (****p* < 0.001). (**B**) Images and densitometric analysis for protein bands altered in senescent vector PANC-1 cells. The left panel shared the same GAPDH control with Figure 2D, all these bands were harvested from the same experiment. Data are presented as the mean ± S.E.M, n = 3 (**p* < 0.05, ***p* < 0.01, ****p* < 0.001). (**C**) The *CPT1C* mRNA level is upregulated after inducing *TP53* mRNA expression with 0.7 μM doxorubicin (Sigma) for 24 h in PANC-1 cells. (**D**) *CPT1C* mRNA is increased after overexpressing 2 μg of TP53 plasmids for 24 h in PANC-1 cells. (**E**) *CPT1C* mRNA expression was downregulated after knockdown of *TP53* mRNA expression with 50 μM si-TP53 for 72 h in PANC-1 cells. The sequences of specific human siRNAs were commercially available (RiboBio) and listed in Supplementary Table 2. The optimal sense against *TP53* was the following: 5'-GCACAGAGGAAGAGAAUCU dTdT-3'. (**F**) Doxorubicin reversed the si-TP53-induced downregulation of *CPT1C* mRNA expression. For the statistical analysis of *TP53* mRNA expression, ^{1} si-Control+Doxorubicin *vs* si-Control+DMSO, ****p* < 0.001; ^{2} si-TP53+DMSO *vs* si-Control+DMSO, ****p* < 0.001; and ^{3} si-TP53+Doxorubicin *vs* si-TP53+DMSO, ***p* < 0.01. For the statistical analysis of *CDKN1A/P53* mRNA level, ^{4} si-Control+Doxorubicin *vs* si-Control+DMSO, ****p* < 0.001; ^{5} si-TP53+DMSO *vs* si-Control+DMSO, **p* < 0.05; and ^{6} si-TP53+Doxorubicin *vs* si-TP53+DMSO, ***p* < 0.01. For the statistical analysis of *CPT1C* mRNA expression, ^{7} si-Control+Doxorubicin *vs* si-Control+DMSO, ****p* < 0.001; ^{8} si-TP53+DMSO *vs* si-Control+DMSO, **p* < 0.05; and ^{9} si-TP53+Doxorubicin *vs* si-TP53+DMSO, ***p* < 0.01. See also Supplementary Figure 7.