TMPRSS11B promotes an acidified microenvironment and immune suppression in squamous lung cancer
Lung cancer is the leading cause of cancer-related deaths worldwide. Existing therapeutic options have limited efficacy, particularly for lung squamous cell carcinoma (LUSC), underscoring the critical need for the identification of new therapeutic targets. We previously identified the Transmembrane Serine Protease TMPRSS11B as a novel gene that promotes transformation of human bronchial epithelial cells and enhances lactate export in LUSC. To determine the impact of TMPRSS11B activity on the host immune system and the tumor microenvironment (TME), we evaluated the effect of Tmprss11b depletion in syngeneic and autochthonous mouse models. Tmprss11b depletion significantly reduced tumor burden in immunocompetent mice and triggered an infiltration of immune cells. RNA FISH analysis and spatial transcriptomics in the Rosa26LSL-Sox2-IRES-GFP; Nkx2-1 fl/fl; Lkb1fl/fl (SNL) model revealed an enrichment of Tmprss11b expression in LUSC tumors, specifically in Krt13+ hillock-like cells. Ultra-pH sensitive nanoparticle imaging and metabolite analysis identified regions of acidification, elevated lactate, and enrichment of macrophages in LUSC tumors. These results demonstrate that TMPRSS11B promotes an acidified and immunosuppressive TME and suggests a potential to therapeutically target this enzyme in LUSC. Overall design: RNA-seq profiling of KLN205 syngeneic tumors expressing scrambled shRNA or shRNAs targeting Tmprss11b. Briefly KLN205 cells expressing scrambled shRNA or Tmprss11b shRNA were injected subcutaneously into the right flanks DBA/2 female mice. Tumor volumes were measured every 3 days using calipers. When the average tumor volume across all the study groups reached 100 mm3, mice were maintained on doxycycline water to induce the expression of the shRNAs for the duration of the experiment. At the terminal timepoint of Day 50 post-injection, the tumors were resected for downstream analysis.Total RNA was isolated from tumor tissues using Trizol, followed by additional cleanup and DNase digestion using RNeasy Mini Kit and subsquently used for RNA-seq profiling.