IL-18R-dependent and independent pathways account for IL-18-enhanced antitumor ability of CAR-T cells.

Interleukin-18 (IL-18) has been demonstrated to augment the antitumor capacity of chimeric antigen receptor-T cells (CAR-T) but the underlying mechanisms are largely unknown. Here we explored the effects and mechanisms of exogenous IL-18 on the antitumor response of CAR-T cells. IL-18 boosted the cytotoxicity of human epidermal growth factor receptor-2 (HER2)-specific CAR-T cells ex vivo and enhanced the antitumor efficacy of the CAR-T cells in immunodeficient mice, moreover, IL-18 improved the antitumor capacity of OVA-specific T cells in immunocompetent mice, indicating the universal enhancing function of IL-18 for adoptive cell therapy. To address the roles of IL-18 receptor (IL-18R) in the enhancing function, we evaluated the effects of IL-18R knockout (IL-18R-/-) condition in immunocompetent host and CAR-T cells on the IL-18-enhanced antitumor activities. Interestingly, IL-18 persisted to improve the antitumor ability of IL-18R intact CAR-T cells in IL-18R-/- mice. For IL-18R-/- CAR-T cells, however, IL-18 still holds the enhancing ability to boost the antitumor efficacy in IL-18R-/- mice, albeit the ex vivo tumor-killing ability was lower than that of IL-18R intact CAR-T cells, indicating that IL-18R-independent pathway is involved in the enhancement. Furthermore, tagged IL-18 binded to the membrane of IL-18R-/- splenic and lymph node cells and IL-18R intact and IL-18R-/- CAR-T cells showed distinct transcriptomic profiles when stimulated by IL-18. These data demonstrate that IL-18R-independent pathways contribute to functions of IL-18.

Effect of isoverbascoside, a phenylpropanoid glycoside antioxidant, on proliferation and differentiation of human gastric cancer cell.

AIM: To investigate the effects of phenylpropanoid glycoside antioxidant isoverbascoside on cell proliferation and differentiation of human gastric cancer cell line MGC 803. METHODS: MGC 803 cells were treated with isoverbascoside. Its effects on cell proliferation, tumorigenicity, enzymatic activities, cell cycles, and gene expression were respectively evaluated with cell counting, tumor formation assay, enzymatic assay, flow cytometer analysis, and Western blotting, with Me2SO as positive control. RESULTS: Isoverbascoside could markedly inhibit cell proliferation in dose- and time-dependent manner. Isoverbascoside 20 micromol/L strikingly suppressed cell tumorigenicity, activities of alkaline phosphatase (ALP), and lactate dehydrogenase (LDH), and caused G0/G1 arrest. The expression of G1 S checkpoint related proteins, p53, p21/WAF1, and p16/INK4, were up-regulated after MGC 803 cells were treated with isoverbascoside 20 micromol/L for 4-8 h. Contrarily, the expression of C-myc protein was suppressed after 8 h treatment. CONCLUSION: Isoverbascoside inhibited cell proliferation, reversed cell malignant phenotypic characteristics, and consequently caused differentiation in MGC 803 cells. These effects might be associated with its activities of causing G0/G1 arrest and regulating the expression of cell cycle related proteins.

Sequencing of p53 mutation in established human hepatocellular carcinoma cell line of HHC4 and HHC15 in nude mice.

AIM:To set up cell lines of human hepatocellular carcinoma in nude mice for the research of cell biology and gene therapy.METHODS:Xenotransplantation of human hepatoma into nude mice was carried out and the growth rate, histopathology and immunology of the nude mice were studied. The DNA from xenografts were analyzed by HBV gen and PCR amplification of a fragment of p53 gene exon 7, which were identified by dot blot hybridization, restriction fragments length polymorphism and DNA sequencing.RESULTS:HHC4 and HHC15 cell lines could be successively transplanted in nude mice and the population doubling time was 7 and 5 days respectively. These strains retained the original characteristics of histopathology, secreting AFP and heteroploid karyotypes in human hepatocellular carcinoma. The fragment of HBV gene was detected in the genomic DNA of both hHCC4 and hHCC15, however only HHC4 secreted HBsAg.The mutation at 250 code (C A) and 249 code (G T) were detected respectively in the genomic DNA of HHC4 and HHC15.CONCLUSION:The two cell lines are useful material for the studying of cell biology and gene therapy in human hepatocellular carcinoma and provide molecular biological trace of relationship between high mortality of hepatoma and AFB1 severe pollution of the daily common foods in this district.