PPARGC1A and hepatocellular carcinoma: Interestingly, SIRT1 positively regulates PGC-1α expression, and increases in PGC-1α expression reversed the beneficial effect of the inhibition of SIRT1 on HCC cell invasion and metastasis by increasing the expression of the mitochondrial biogenesis-related proteins transcription factor A, mitochondrial (TFAM), cytochrome C oxidase subunit 4, isoform 1 (COXIV), and translocase of outer mitochondrial membrane 20 (TOMM20) [19].