The effect of secreted cytokines from killer cells induced by cytokines on apoptosis of hepatic cancer stem cells / 肿瘤

ABSTRACT

Objective: To investigate the effect of secreted cytokines from cytokine-induced killer (CIK) cells on apoptosis of human hepatic cancer stem cells (HCSCs). Methods: The HCSCs were enriched from human hepatic cancer cell line HepG2 by serumfree suspension culture and sphere-forming assay. The expressions of CD90 and CD1 33 of HCSCs were examined by flow cytometry (FCM). The tumorigenicity of HCSCs was detected by nude mouse transplantation tumor experiment. The CIK cells were produced from suspended peripheral blood mononuclear cells (PBMCs) induced by interferon γ (IFNγ), CD3 monoclonal antibody and recombinant human interleukin-2 (rhIL-2). The HCSCs were cultured together with CIK cells at different density in a Transwell chamber and cultured separately by the membrane of the Transwell chamber for 24 and 48 h, respectively. The apoptosis of HCSCs, which were cultured with CIK cells for 24 and 48 h, was analyzed by FCM. The expression levels of caspase-3 mRNA and protein were detected by reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting, respectively. Results: The result of FCM revealed that the stem cell markers CD90 and CD1 33 were highly expressed on the surface of HCSCs. The nude mouse transplantation tumor experiment showed that HCSCs possessed a high ability of tumorigenicity. The apoptosis of HCSCs could be significantly induced by secreted cytokines from CIK cells as compared with that of the control group (P < 0.01). The caspase-3 mRNA and protein expression levels were significantly up-regulated in HCSCs induced by secreted cytokines from CIK cells. Conclusion: The secreted cytokines from CIK cells can induce apoptosis of HCSCs, and this effect may be related to upregulation of caspase-3 expression.