Study on the synergistic proliferation-inhibiting and apoptosis-inducing effects of recombinant human-derived interleukin-24 and recombinant human-derived decorin on human hepatocellular carcinoma cells HepG2 / 肿瘤研究与临床

ABSTRACT

Objective To investigate the synergistic proliferation-inhibiting and apoptosis-inducing effects of recombinant human-derived interleukin-24 (rhIL-24) and recombinant human-derived decorin (rhDCN) on human hepatocellular carcinoma cells HepG2.Methods Cellular growth and morphological changes of HepG2 cells were observed under the inverted microscope at 48 h after being transiently transfected with pcDNA3.1 (+)-IL-24 and pcDNA3.1 (+)-DCN by Lipofectamine.The proliferation-inhibiting effects of IL-24 and DCN on HepG2 cells,respectively and jointly,were observed with MTT assay at 24 h,48 h and 72 h post-transfection.Apoptosis and cell-cycle of HepG2 cells were analyzed by flow cytometry at 48 h post-transfection.Results Compared to control groups,the cells of target gene groups presented typically changes of proliferation inhibition and apoptotic morphology,which occurred obviously in co-transfection group.The results of MTT assay showed that at 48 h and 72 h post-transfection,the profiferation-inhibiting rates in the group of cells co-transfected with IL-24 and DCN were (31.88±6.57) ％ and (36.83±3.76) ％,respectively,displaying significant difference with those of other groups (P ＜ 0.01).The results of flow cytometry showed that IL-24 and DCN can induce HepG2 cells apoptosis to some extent.Compared to the early apoptosis rate of cells of control groups,plasmid (2.98±0.72) ％,blank cell (3.50±0.92) ％,IL-24 (20.01±1.08) ％ and DCN (22.20±0.91) ％,a statistically remarkable apoptosis rate,(32.56±0.90) ％,can be seen in the group of cells treated with IL-24 and DCN jointly (P ＜ 0.01).The result of cell cycle analysis revealed that,compared to control groups,the proportion of cells was higher in the phase of G2/M in the IL-24 group (11.24±0.35) ％ and in the phase of G0/G1 in the DCN group (77.93±0.67) ％.The proportions of cells in the phases of G2/M increased to (71.36±0.60) ％ and that of G0/G1 statistically increased to (10.39±0.67) ％ in the group of cells co-transfected with IL-24 and DCN (P ＜ 0.01).Conclusions Combinatorial treatment of HepG2 cells with IL-24 and DCN can exert stronger synergistic proliferation-inhibiting effect and apoptosisinducing activity-in comparison to single therapies.IL-24 and DCN can induce cell cycle arrest on HepG2 cells,occurred in the phase of G2/M and G0/G1,respectively.Promoting effect of cell cycle arrest in the phase of both G2/M and G0/G1 can be seen on HepG2 cells co-transfected with IL-24 and DCN,which maybe the possible mechanism of the synergistic proliferation-inhibiting and apoptosis-inducing effect.