LAUSR

Glioblastoma multiforme (GBM) is the most aggressive brain tumor with chemo-resistant, immunosuppressive, and invasive property. Despite the application of standard therapies which include a combination of surgery, radiotherapy, and temozolomide (TMZ) chemotherapy, tumor inevitably recurred (in patients) at peritumoral region. Targeting multiple arms of the GBM-mediated immunosuppressive ability and their invasiveness can improve therapeutic efficacy. Genomic screening identified that IL-19 is a predicted immune suppressive cytokine in peritumoral region and was associated with poor survival in patients with GBM. IL-19 blockade inhibited both TMZ-sensitive and resistant tumor progression. Molecular studies revealed that silencing IL-19 markedly abrogated IL-19-WISP1-AKT signaling to inhibit TMZ-resistant GBM cell invasion, as well as weaken its suppressive ability on CD8+T cell activation. Single cell transcriptome analysis revealed that IL-19 blockade promoted T cell activation, upregulated effector function of T cell subsets, and reprogrammed tumor-associated macrophage subsets toward a weakened pro-tumoral phenotypes. Thus, Targeting IL-19 can be a novel therapeutic strategy to reverse immunosuppressive microenvironment and restrict invasiveness of chemo-resistant GBM. Citation Format: Gilbert A. Lee, Cheng-Yu Chen. IL-19 blockade reprograms glioblastoma immunosuppressive microenvironment and overcomes chemo-resistance as revealed by single-cell transcriptome analyses. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5652.