Abstract
Metabolic reprogramming is a prominent feature of clear cell renal cell carcinoma (ccRCC). Protein succinylation influences cell metabolism, but its effects on ccRCC tumorigenesis remain largely uncharacterized. In this study, we investigated the lysine succinylome of ccRCC tissues by using tandem mass tag labeling, affinity enrichment, liquid chromatography-tandem mass spectrometry and integrated bioinformatics analyses. Proteins involved in metabolic process, the tricarboxylic acid (TCA) cycle, oxidation-reduction and transport processes were subject to succinylation. A total of 135 sites in 102 proteins were differentially succinylated between ccRCC and adjacent normal tissues. Succinate dehydrogenase complex subunit A (SDHA), which is involved in both the TCA cycle and oxidative phosphorylation, was desuccinylated at lysine 547 in ccRCC. SDHA desuccinylation by mimetic mutation (K547R) suppressed its activity through the inhibition of succinate dehydrogenase 5 (SDH5) binding, further promoted ccRCC cell proliferation. The desuccinylase sirtuin5 (SIRT5) was found to interact with SDHA, and SIRT5 silencing led to the hypersuccinylation and reactivation of SDHA. SIRT5 was also found to be upregulated in ccRCC tissues, and its silencing inhibited ccRCC cell proliferation. This indicates that SIRT5 promotes ccRCC tumorigenesis through inhibiting SDHA succinylation. This is the first quantitative study of lysine succinylome in ccRCC, through which we identified succinylation in core enzymes as a novel mechanism regulating various ccRCC metabolic pathways. These results expand our understanding about the mechanisms of ccRCC tumorigenesis and highlight succinylation as a novel therapeutic target for ccRCC.