This study aims to investigate the role of slient mating-type information regulation 2 homolog 1(SIRT1)/tuberous sclerosis complex 2(TSC2)/mammalian target of rapamycin(mTOR) signaling pathways in the Periplaneta americana extract CⅡ-3-induced senescence of human leukemia K562 cells. K562 cells were cultured in vitro and treated with 0(control), 5, 10, 20, 40, 80, and 160 μg·mL~(-1) of P. americana extract CⅡ-3. Cell counting kit-8(CCK-8) and flow cytometry were employed to examine the proliferation and cell cycle of the K562 cells. Senescence-associated β-galactosidase stain kit(SA-β-gal) was used to detect the positive rate of senescent cells. Mitochondrial membrane potential was detected by flow cytometry. The relative mRNA level of telomerase reverse transcriptase(TERT) was determined by fluorescence quantitative PCR. The mRNA and protein levels of SIRT1, TSC2, and mTOR were determined by fluorescence quantitative PCR and Western blot, respectively. The results showed that CⅡ-3 significantly inhibited the proliferation of K562 cells and the treatment with 80 μg·mL~(-1) CⅡ-3 for 72 h had the highest inhibition rate. Therefore, 80 μg·mL~(-1) CⅡ-3 treatment for 72 h was selected as the standard for subsequent experiments. Compared with the control group, CⅡ-3 increased the proportion of cells arrested in G_0/G_1 phase, decreased the proportion of cells in S phase, increased the positive rate of SA-β-Gal staining, elevated the mitochondrial membrane potential and down-regulated the mRNA expression of TERT. Furthermore, the mRNA expression of SIRT1 and TSC2 was down-regulated, while the mRNA expression of mTOR was up-regulated. The protein expression of SIRT1 and p-TSC2 was down-regulated, while the protein expression of p-mTOR was up-regulated. The results indicated that P. americana extract CⅡ-3 induced the senescence of K562 cells via the SIRT1/mTOR signaling pathway.
Keywords: K562 cells; Periplaneta americana extract CⅡ-3; SIRT1; mTOR; senescence.