The suppressive effect of co-inhibiting PD-1 and CTLA-4 expression on H22 hepatomas in mice

Abstract

ObjectiveWe investigated the suppressive effect of siRNA-mediated co-inhibition of PD-1 and CTLA-4 expression on H22 hepatomas in mice.MethodsMurine H22 cells were cultured in vivo in ICR mice. An allograft tumor model was also established in another ICR mouse group. The tumor-bearing mice were randomly divided into four groups: control, single PD-1 siRNA, single CTLA-4 siRNA, and double PD-1 + CTLA-4 siRNAs. The survival time and physiological condition of the mice were observed after the injection of the siRNAs and placebo. The volume and weight of the solid tumor were measured to assess the inhibition of the tumor. To assess the effects of siRNAs on mouse immune function, the protein levels of IFN-γ and IL-10 in the blood and PD-L1 in the tumor and liver were determined using ELISA, and the mRNA levels of IFN-γ, PD-L1, PD-1, CTLA-4, IL-6 and Survivin in the tumor, liver and spleen were determined using quantitative RT-PCR. The ratios of Bax and Bcl-2 protein were determined via western blot to analyze the effect of siRNAs on tumor cell apoptosis.ResultsThe anti-tumor effect appeared in all groups with siRNA-mediated inhibition. The tumor growth suppression was stronger in the group with double inhibition. The weight and volume of the tumors were significantly lower and the survival rate improved in the three siRNA groups. IFN-γ levels increased but IL-10 levels decreased in the blood of the siRNA group mice compared with the results for the control group. In the tumor and spleen tissue, the IFN-γ levels significantly increased, but in the liver tissue they significantly decreased in the three siRNA groups. The results of quantitative RT-PCR showed that the mRNAs for PD-1 and CTLA-4 were downregulated in spleen tissue in the three siRNA groups, while the PD-L1 mRNA and protein levels increased significantly in the tumor, but decreased in the liver. Survivin and IL-6 mRNA levels decreased in the tumor. Western blot results showed that ratio of Bax and Bcl-2 had significantly increased. These results indicated that downregulating PD-1 and CTLA-4 could increase the body’s immune response and promote apoptosis of tumor cells.ConclusionCo-inhibiting the expressions of PD-1 and CTLA-4 can effectively suppress the growth of H22 hepatoma and promote the apoptosis of tumor cells in mice. Blocking PD-1 and CTLA-4 can improve the vitality of T cells, and improve the immune environment and response.

Evaluation of efficiency of Fas-mediated apotosis of peripheral blood lymphocytes in patients with type 1 diabetes mellitus

“…В исследованиях с использованием изолированных островков поджелудочный железы человека показано, что воздействие стрессовых факторов (гипергликемия, избыточное количество свободных радикалов, активные формы кислорода, продукция IL-1β клетками микроокружения) усиливает экспрессию Fas на β-клетках, что приводит к их гибели по механизму Fas-опосредованного апоптоза [18]. Иммунокомпетентные клетки, инфильтрирующие островковую ткань поджелудочный железы, продуцируют провоспалительные цитокины: интерлейкин 1b (IL-1b), фактор некроза опухолей α (TNF-a) и интерферон g (IFN-g), известные своими проапоптогенными свойствами [16,19,20]. IL-1β индуцирует усиление экспрессии Fas на β-клетках, что повышает их готовность к Fas-опосредованному апоптозу, который реализуется аутореактивными Т-клетками, экспрессирующими FasL.…”

Mouse Models of Hepatocellular Carcinoma: Classification, Advancement, and Application

“…The early-stage transplantation model was mainly based on the transplantation with the same gene strain tumor cells on homologous mice. Transplanted H22 cells into BALB/C mice ( 78 ) or Hepa1-6 cells into C57 mice ( 79 ) subcutaneously or in situ could be constructed as a mouse resource HCC model. Subcutaneous tumors are easier to be observed and monitored, and in situ tumors mimic the local environment better ( 80 ).…”

Application of lipid-based nanoparticles in cancer immunotherapy

“…siRNA against PD-L1 can preferentially transfer CD11c+ PD-L1+ tolerogenic DCs into potent stimulators of CTLs in TMEs through PD-L1 downregulation and multiple TLRs activation ( 119 ). The antitumor efficacy of siRNA against PD-L1 can be enhanced by co-inhibiting with CTLA-4 ( 120 ). Another study also indicated that siRNA against PD-L1 or PD-L1 improved effector functions of tumor-specific CD4+ and CD8+ T cells in vitro ( 121 ), suggesting that PD-L1/PD-L2 siRNA is an exciting strategy to inhibit the immune suppressive tumor-specific T cells.…”