LAP+CD4+T cells regulate the anti-tumor role of CIK cells in colorectal cancer through IL-10 and TGF-β.

The rate of colorectal cancer (CRC) is increasing. Adoptive immune cell therapy (ACT) is a research hotspot in CRC treatment, and the common adoptive cells are cytokine-induced killer cells (CIK). The problem of ACT is that some regulatory T cells (Treg) will affect the efficacy. Latent associated polypeptide (LAP)+CD4+T is a new Treg, and its immunosuppressive effect is much higher than that of traditional Tregs. This research mainly explored the influence of LAP+CD4+T cells on anti-tumor lethality of CIK cells, so as to fill this gap. The LAP+CD4+T CIK cells and LAP-CD4+T CIK cells were sorted by immunomagnetic beads. LAP+CD4+T cells were expanded in vitro, and high expression cytokine genes were screened by RT-qPCR. LAP+CD4+T and LAP-CD4+T CIK cells were co-cultured to test cyto-activity. Transplanted tumor models of CRC were established in nude mice, which were randomized into a control group (CG), CIK group, LAP (-) group, LAP (+) group, IL-10 siRNA group, and TGF-siRNA group, and the tumor growth in each group was observed. The research results revealed that interleukin-10 (IL-10) and transforming growth factor-β (TGF-β) were highly expressed in LAP+CD4+T cells. LAP+CD4+T could effectively suppress CIK cell proliferation and activity. LAP-CD4+T could suppress IL-10 and TGF-β, and inhibit CIK cell apoptosis, proliferation, and tumor growth, thus improving their anti-tumor lethality. LAP+CD4+T cells regulate the anti-tumor role of CIK cells in CRC through IL-10 and TGF-β. AJTR