NK-resistant Lines Research Articles

SURG-09. TARGETING A SHARED GLIOBLASTOMA CELL STATE THROUGH ADAPTIVE NATURAL KILLER CELLS AUGMENTED WITH TRISPECIFIC KILLER CELL ENGAGER (TRIKE) IMMUNE-MODULATOR AGAINST CD276

Abstract INTRODUCTION T and NK (Natural Killer) cells have emerged as promising platforms for immunotherapy. While T cells require antigen priming and complex MHC-dependent interactions, NK cells exhibit limited persistence and limited antigen specificity. Trispecific Killer cell Engagers (TriKEs) are constructs developed to address these limitations, combining interleukin 15 (IL15, to enhance persistence), a single-chain antibody fragment against CD16 (to immune-activate NK), and a second fragment targeting a tumor surface marker. Objective: In this study, we identified CD276 (B7H3) as the surface marker optimal for an anti-glioblastoma TriKE and tested its effect on the anti-glioblastoma activity of NK cells. Method: Mass-spectrometry, RNA-Seq, and single cell RNA-Seq profiling of glioblastoma lines. Laboratory characterization and murine modeling Result: Orthogonal analysis of mass-spec identified cell surface molecules enriched in glioblastoma lines and RNA-seq of lines with defined sensitivity to NK cells identified surface proteins highly expressed in NK-resistant lines. Screening of these candidates for genes that showed poor survival association using the TCGA identified CD276. qPCR analysis confirmed higher CD276 expression in the NK-resistant lines, though expression is also detected in NK-sensitive glioblastoma lines. Western blotting analysis and TCGA analysis showed higher level CD276 expression in all glioblastoma subtypes (proneural, neural, mesenchymal, and classical) relative to normal brain. Single cell RNA-Seq of clinical specimens confirmed high expression of CD276 in glioblastoma cells in OPC-like, NPC-like, AC-like, and MES-like cell states. Co-incubation of a IL15, CD16, and CD276 targeting TriKE with either adaptive or iPS derived NK cells enhanced anti-glioblastoma cytotoxicity against cells otherwise refractory to NK treatment in vitro. Synergy between these reagents were also observed in vivo upon orthotopic injection. CONCLUSION Our results suggest that a therapeutic strategy combining intra-tumoral injections of NK cells and a B7H3 specific TriKE holds promise and warrants clinical trial consideration.

Natural killer (NK)-like cytotoxic activity of allospecific T cell receptor-gamma,delta+ T cell clones. Distinct receptor-ligand interactions mediate NK-like and allospecific cytotoxicity.

We recently generated a series of human alloantigen-specific, CD3+,TCR-gamma,delta+ clones by stimulating CD3+,CD4-,CD8- T cells from normal individuals with allogeneic lymphoblastoid cell lines (LCL). As reported previously, these clones display cytotoxic activity against their specific stimulators but not against irrelevant LCL. Further studies of these and other TCR-gamma,delta+ clones, described in this report, indicate that most but not all of these clones express the NK cell associated marker, NKH-1 or Leu-19, and kill NK-sensitive targets such as the K562 and Molt 4 lines, but not an irrelevant LCL or NK-resistant line, Raji. TCR-gamma,delta+ clones which lacked expression of Leu-19 lysed their allospecific targets but had no detectable NK activity. The allospecific cytotoxicity of Leu-19+ and Leu-19- clones was inhibited by mAb to CD3 or the TCR delta-chain. In contrast, the NK-like activity of the Leu-19+ clones was enhanced by these antibodies over a wide range of antibody concentration. Although mAb to LFA-1 markedly inhibited both the allospecific and NK-like activity of these clones, an HLA class I framework specific mAb (W6/32) had no effect on NK-like cytolysis but did inhibit allospecific killing, suggesting that the target structures on the surface of allospecific and NK-sensitive cells are distinct. The receptors utilized by the TCR-gamma,delta+ clones to recognize NK-sensitive and allospecific targets are also distinct, since killing of NK-sensitive targets was blocked by the presence of cold (unlabeled) NK-sensitive cells but not by cold allospecific targets, whereas allospecific cytolysis was inhibited by cold allospecific targets but not by NK-sensitive cells. We conclude that some CD3+,TCR-gamma,delta+ clones exhibit NK-like as well as allospecific killing and that these two activities are mediated by distinct receptor-ligand interactions.