Bi-Specific Killer Cell Engager Enhances NK Cell Activity against Interleukin-13 Receptor Alpha-2 Positive Gliomas

Abstract

Glioblastoma (GBM) is a lethal brain tumor with limited therapeutic options. Bi-specific killer cell engagers (BiKEs) are novel immunotherapies designed to engage natural killer (NK) cells against cancer. We designed a BiKE molecule consisting of a single-domain CD16 antibody, an interleukin-15 linker, and a single-chain variable antibody against the glioma-associated antigen interleukin 13 receptor alpha 2 (IL13Rα2). Recombinant BiKE protein was expressed in HEK cells and purified. Flow cytometric analysis of co-cultures of peripheral blood-derived NK cells with GBM6 and GBM39 patient-derived xenograft lines revealed significantly increased activation of NK cells (CD25+CD69+) and increased glioma cell killing following BiKE treatment compared to controls (n = 4, p < 0.01). Glioma cell killing was also confirmed via immunofluorescence staining for cleaved caspase-3 (p < 0.05). In vivo, intracranial delivery of NK cells with BiKE extended median survival in mice bearing GBM6 (p < 0.01) and GBM12 (p < 0.01) tumors compared to controls. Finally, histological analysis of brain tissues revealed a higher frequency of peritumoral NK cells in mice treated with BiKE than with NK cells alone (p < 0.05). In conclusion, we demonstrate that a BiKE generated in a mammalian expression system is functional in augmenting NK cell targeting of IL13Rα2-positive gliomas.

Expression of Interleukin-13 Receptor Alpha 2 in Brainstem Gliomas

“…There are six ongoing clinical trials, registered in clinicaltrial.gov, exploring its safety and efficacy in treating a variety of brain malignancies, including melanoma, ependymoma, medulloblastoma, and glioblastoma. Recent reports highlight the promising effects of novel immune cell therapies targeting IL13Ra2, such as bispecific T-cell engagers (BiTEs) and bispecific killer cell engagers (BiKEs), demonstrating their cytotoxicity against GBM, potentially showing more therapeutic potential than traditional immune cell therapies [ 35 , 36 ]. Apart from immune cell therapies, targeting IL13Ra2 with antibody treatments is another promising avenue.…”

Harnessing immune cells to eliminate HIV reservoirs

“…Also an inspiration from the cancer field [85–88], various bispecifics are under investigation to enhance clearance of HIV-infected cells. Bispecific killer cell engagers (BiKEs) [89] and bispecific T cell engagers (BiTEs) [90] show preclinical promise in enhancing directed cytotoxicity of NK cells and T cells, respectively, towards HIV-infected targets.…”