Abstract: Abstract: Objective　To explore the effect of Sirtuin5 (SIRT5) on the proliferation, apoptosis and migration of Lovo cells in high glucose environment and its possible mechanism. Methods　Lovo cells with high expression of SIRT5 were cultured in vitro with high glucose medium (4 500 mg/L) and ordinary medium (2 000 mg/L). Lentivirus transfection experiment was performed. SIRT5-RNAi transfected with SIRT5-RNAi lentivirus was used as KD group, blank control group with no intervention was used as MOCK group, and negative control group transfected with control RNAi lentivirus was used as NC group. The cell proliferation was observed by MTT assay, apoptosis rate was determined by flow cytometry, and cell migration rate was measured by scratch test. The expressions of mammalian target of rapamycin (mTOR), hypoxia inducible factor-1α (HIF-1α), M2 pyruvate kinase (PKM2) and hexokinase2 (HK2) were detected by real-time PCR, and their protein expressions were detected by Western blot assay. Results　Compared with NC and MOCK, the proliferation decreased at the 3-5 day following SIRT5 silence, the cell apoptosis rate increased and the cell migration rate decreased in KD with high glucose medium (P＜0.01). The proliferation decreased at the 5-day following SIRT5 silence (P＜0.05), but no significant difference in the cell apoptosis rate between KD and NC groups at the 1-4 day. The expressions of SIRT5, mTOR, HIF-1 α, PKM2, HK2 mRNA and proteins were significantly lower in KD group than those in NC and MOCK groups with high glucose medium (P＜0.05). Conclusion　SIRT5 promotes the development of colon cancer in high glucose environment, which may be related with the regulating glycolysis by affecting the key glucose metabolism enzymes HK2 and mTOR/HIF-1α/PKM2 signal pathway. 

Key words: colonic neoplasms, cell line,tumor;sirtuins, hypoxia-inducible factor 1,alpha subunit, pyruvate kinase, hexokinase, high glucose, mammalian target of rapamycin, sirtuin 5