Activation of cellular immunity and marked inhibition of liver cancer in a mouse model following gene therapy and tumor expression of GM-SCF, IL-21, and Rae-1

Abstract

BackgroundCancer is both a systemic and a genetic disease. The pathogenesis of cancer might be related to dampened immunity. Host immunity recognizes nascent malignant cells – a process referred to as immune surveillance. Augmenting immune surveillance and suppressing immune escape are crucial in tumor immunotherapy.MethodsA recombinant plasmid capable of co-expressing granulocyte-macrophage colony- stimulating factor (GM-SCF), interleukin-21 (IL-21), and retinoic acid early transcription factor-1 (Rae-1) was constructed, and its effects determined in a mouse model of subcutaneous liver cancer. Serum specimens were assayed for IL-2 and INF-γ by ELISA. Liver cancer specimens were isolated for Rae-1 expression by RT-PCR and Western blot, and splenocytes were analyzed by flow cytometry.ResultsThe recombinant plasmid inhibited the growth of liver cancer and prolonged survival of tumor-loaded mice. Activation of host immunity might have contributed to this effect by promoting increased numbers and cytotoxicity of natural killer (NK) cells and cytotoxic T lymphocytes (CTL) following expression of GM-SCF, IL-21, and Rae-1. By contrast, the frequency of regulatory T cells was decreased, Consequently, activated CTL and NK cells enhanced their secretion of INF-γ, which promoted cytotoxicity of NK cells and CTL. Moreover, active CTL showed dramatic secretion of IL-2, which stimulates CTL. The recombinant expression plasmid also augmented Rae-1 expression by liver cancer cells. Rae-1 receptor expressing CTL and NK cells removed liver cancer.ConclusionsThe recombinant expression plasmid inhibited liver cancer by a mechanism that involved activation of cell-mediated immunity and Rae-1 in liver cancer.

Anti-cancer efficacy of biotinylated chitosan nanoparticles in liver cancer

“…Furthermore, Bio-CS / plasmid DNA has been shown to increase IFN-γ and IL-2 levels, whereas the ratio and cytotoxicity of NK and CTL cells was further reported to increase significantly, along with a concomitant reduction in the percentage of Treg cells. This finding is consistent with the previous study conducted by our group that indicated the capacity of the combination effect of GM-CSF, IL-21 and Rae-1 to enhance cellular immunity [ 7 ]. In the present study, the Bio-CS formulation was shown to promote cellular immune function.…”

“…Biotin, calf serum, DNase I, RPMI 1640 powder, Cell Counting Kit-8 (CCK-8) and tetramethylethylenediamine (TEMED) were purchased from Beijing Jiakangyuan Pharmaceutical Co., Ltd (Beijing, China), Hangzhou Sijiqing Pharmaceutical Co., Ltd (Hangzhou, China), TaKaRa Biomedicals (Tokyo, Japan), Gibco/Invitrogen Inc (CA, USA), Dojindo Molecular Technologies Inc. (Shanghai, China)and Sinopharm Chemical Reagent Co., Ltd (Shanghai, China), respectively. The plasmid DNA (pGM-CSF-GFP-IRES-Rae-1-IL-21) was obtained as described before [ 7 ].…”

“…Previous studies conducted by our group, demonstrated the construction of pGM-CSF-GFP-IRES-Rae-1-IL-21 as an “immune escape system”. The latter process can improve the activity of NK and CTL cells, reduce the percentage of regulatory T cells, increase the expression of NKG2D ligand Rae-1 in hepatocellular carcinoma cells and promote the recognition of hepatocellular carcinoma cells by CTL and NK cells in order to ultimately enhance immune surveillance and inhibit immune escape [ 7 ]. The efficacy of the “immune escape system” in the mouse model of orthotopic liver cancer remains unknown.…”

Adenovirus-mediated interleukin 21 gene transfer enhances antitumor immunity and reduces tumorigenicity of Hepa1–6 in mice

“…We also observed that the antitumor immune response was significantly enhanced in Ad5-IL-21-Hepa1–6 mice, which is consistent with the results of Pan et al (16) and Cheng et al (17), but the antitumor effect is much better, due to the infection and expression efficiency of IL-21 mediated by Ad5 compared with naked plasmid injection. The killing ability of NK and T cells in mouse spleen was significantly enhanced.…”

“…The immunotherapy with IL-21 in combination with sPD-1 was observed to induce antitumor immune response. Cheng et al (17) injected recombinant plasmid capable of co-expressing GM-SCF, IL-21 and Rae-1 into a H22 cell-bearing mouse, and the recombinant expression plasmid inhibited liver cancer by a mechanism that involved activation of cell-mediated immunity in liver cancer. However, the efficiency of gene expression by naked plasmid injection was limited, and the therapeutic effect requires improvement.…”