Effect of rapamycin on the biological behaviors of human non-Hodgkin lymphoma Raji cells and its mechanism

Abstract

Objective To investigate the effects of rapamycin on the biological behaviors of human non-Hodgkin lymphoma Raji cells with different concentrations and time, and to explore its mechanism. Methods Different concentrations (0, 10, 50, 100, 250, 500 nmol/L) of rapamycin were used in Raji cells for 24, 48, 72 h respectively. The apoptosis of Raji cells was detected by using CCK-8 method, and flow cytometry was used to detect the cell apoptosis and cycle of Raji cells. The enzymatic activity of Caspase-3 and Caspase-9 in Raji cells was detected by Caspase-3 and Caspase-9 activity testing kit. The expressions of bcl-2, p53 protein and mRNA were detected by Western blot method and reverse transcription-polymerase chain reaction (RT-PCR). Results The proliferative inhibition rate of Raji cells was increased from (23.7±4.2)% to (51.7±3.7)%, the cell apoptosis rate was increased from (4.9±1.9)% to (20.5±1.5)%, the proportion of G0/G1 was increased from (40.8±1.4)% to (63.6±1.7)%, the Caspase-3 enzyme activity of Raji cell in 24 h was increased from 0.16±0.05 to 1.08±0.04, Caspase-9 enzyme activity was increased from 0.19±0.04 to 1.34±0.06 after 24 h with the increasing concentration of rapamycin from 0 nmol/L to 500 nmol/L (P < 0.01). The mRNA of bcl-2 was decreased from 0.90±0.03 to 0.46±0.03, and mRNA of p53 was increased from 2.51±0.41 to 5.85±0.21. The protein expression of bcl-2 was reduced and the protein expression of p53 was increased. The experimental results of Raji cells in 48 h and 72 h were consistent with the experimental results of 24 h. Conclusion Rapamycin may inhibit the proliferation of Raji cells through Caspase-3, Caspase-9, bcl-2, p53 and induce its cell apoptosis. Key words: Lymphoma, non-Hodgkin; Sirolimus; Apoptosis; Caspase 3; Caspase 9; Genes, bcl-2; Genes, p53