KHYG-1 cells with EGFRvIII-specific CAR induced a pseudoprogression-like feature in subcutaneous tumours derived from glioblastoma-like cells

Abstract

Background/Aim: We previously established a novel type of epidermal growth factor receptor variant III (EGFRvIII)-specific chimeric antigen receptor (CAR)- expressing natural killer (NK) cell line, designated EvCARKHYG- 1, which inhibited the growth of glioblastoma (GBM) cells in vitro via apoptosis. Materials and Methods: We investigated the cytokine-producing effect of EvCARKHYG- 1 cells on GBM-like cell lines and their antitumour effect using in vivo xenograft assays. Results: EvCARKHYG- 1 cells produced interleukin-2, interferon-γ, and tumour necrosis factor-α on EGFRvIII-expressing U87MG cells. In vivo xenograft assays showed that EvCAR-KHYG- 1 cells did not reduce the volume of subcutaneous tumours derived from EGFRvIII-expressing U87MG cells but did reduce tumour cell occupancy. Conclusion: EvCAR-KHYG- 1 cells led to expression of cellular immunity-related cytokines on EGFRvIII-expressing U87MG in vitro but did not inhibit tumour progression due to the induction of a pseudo progression-like pathological feature. Future studies investigating the effect of different conditions in vivo are required to study the inhibition of tumour progression in GBM.