SIRT4 is the molecular switch mediating cellular proliferation in colorectal cancer through GLS mediated activation of AKT/GSK3β/Cyclin D1 pathway

Mitochondria-localized sirtuin 4 (SIRT4) is associated with malignant phenotypes in colorectal cancer. However, the molecular mechanisms that drive SIRT4-mediated carcinogenesis are unclear. Initially, we confirmed expression of SIRT4 in colorectal cancer through public database and in colorectal cancer patient tissues using quantitative real-time reverse transcription PCR. We established HCT116 colorectal cells that overexpressed SIRT4 and HT29 cells were transfected with plasmids bearing a small interfering RNA siRNA construct to silence SIRT4. Assays to determine the malignant phenotypes (proliferation, invasion and migration) were performed. Xenograft in-vivo models were also constructed. A protein interactome network was built using differentially expressed proteins identified using the liquid chromatography/tandem mass spectrophotometry, the findings of which were confirmed using coimmunoprecipitation, western blotting, and phenotype rescue experiments. Decreased SIRT4 expression was associated with malignant phenotypes in vitro and in vivo. The ribosomal biogenesis pathway was enriched in the interactome network. SIRT4 suppression activated glutaminase, thereby initiating AKT activation. Our research provided novel insights into the molecular mechanisms underlying colorectal cancer, and identified that SIRT4 exerts its antitumor activity in colorectal cancer possibly dependent on glutaminase to inhibit proliferation, migration, and invasion via the AKT/GSK3β/CyclinD1 pathway.