Inhibition of squamous cancer growth in a mouse model by Staphylococcal enterotoxin B-triggered Th9 cell expansion

Abstract

Currently, therapy for squamous cancer (SqC) is unsatisfactory. Staphylococcal enterotoxin B (SEB) has strong immune regulatory activity. This study tests the hypothesis that SEB enforces the effect of immunotherapy on SqC growth in a mouse model. C3H/HeN mice and the SqC cell line squamous cell carcinoma VII were used to create an SqC mouse model. Immune cell assessment was performed by flow cytometry. Real-time RT-PCR and western blotting were used to evaluate target molecule expression. An apoptosis assay was used to assess the suppressive effect of T helper-9 (Th9) cells on the SqC cells. The results showed that immunotherapy consisting of SEB plus SqC antigen significantly inhibited SqC growth in the mice. The frequency of Th9 cells was markedly increased in the SqC tissue and mouse spleens after treatment. SEB markedly increased the levels of signal transducer and activator of transcription 5 phosphorylation and the expression of histone deacetylase-1 (HDAC1) and PU.1 (the transcription factor of the interleukin 9 (IL-9) gene) in CD4 T cells. Exposure to SqC-specific Th9 cells markedly induced SqC cell apoptosis both in vitro and in vivo. In conclusion, the administration of SEB induces Th9 cells in SqC-bearing mice, and theseTh9 cells inhibit SqC growth.

TGF-β enhances the cytotoxic activity of Vδ2 T cells

“…We previously reported that TGF-β-expanded Vδ2 T cells also produce high amounts of IL-9, 17 but this is most likely not the reason for the enhanced cytotoxicity observed in our present study, since neutralizing anti-IL-9 antibodies did not affect the cytotoxic activity. Miao et al described a direct cytotoxic effect of IL-9 (produced by Th9 T cells) on squamous cancer cells 27 and Nalleweg et al reported that IL-9 counteracted the proliferation of an epithelial tumor cell line. 28 However, most other studies reporting a beneficial effect of IL-9-producing T cells on antitumor immunity were in vivo studies, in which IL-9 indirectly affected anti-tumor immunity.…”

“…For the surface labeling of adherent tumor cells, the cells were detached by accutase. For intracellular staining the following mAb were used: anti-granzyme A (clone: CB9), anti-granzyme B (clone: GB11), anti-IFN-γ (clone: 4S.B3), anti-IL-9 (clone: MH9A3), anti-TNF-α (clone: 359-81-11), anti-perforin (clone: dG9), IgG1 (clone: MOPC-21) and IgG2b (clone: [27][28][29][30][31][32][33][34][35] isotype controls (all from BD Biosciences). For intracellular staining, cells were stimulated for 6 h with 10 ng/mL 12-O-tetradecanoylphorbol-13-acetate (TPA; Sigma Aldrich, Missouri, USA) and 1 µg/mL ionomycin (EMD Millipore/Calbiochem, Darmstadt, Germany) as indicated; 3 µM monensin (EMD Millipore/ Calbiochem) was added 4 h before fixation in each case.…”

Human Vδ2 T cells are a major source of interleukin-9

“…Th9 cells themselves can exert enhanced antitumor activity (41), but IL-9 might also act indirectly via mast cells (8) or recruitment of dendritic cells to the tumor site (7). Significant numbers of γδ T cells are present among tumor-infiltrating lymphocytes (TILs) in many cancer types (42), and, in fact, the proportion of γδ T cells among TILs is the best predictive parameter across 25 human tumor entities (43).…”

IL-9 and IL-9-producing cells in tumor immunity

“…Research has shown that Id3 can regulate the antitumor immunity of experimental melanoma-bearing mice by negatively regulating the differentiation of Th9 cells [86]. A metabolite of a bacterium, staphylococcal enterotoxin B (SEB) can induce the proliferation of Th9 cells and inhibit the growth of mouse squamous carcinoma [87]. It has also been reported that SEB can promote the induction of specific Th9 cells to inhibit glioma cell growth [88] ( Table 3).…”