GSE183544
Activin-A impedes the establishment of CD4+ T cell exhaustion and enhances anti-tumor immunity in the lung [RNA-seq]
Background: Although tumor-infiltrating T cells represent a favorable prognostic marker for cancer patients, the majority of these cells are rendered with an exhausted phenotype. Hence, there is an unmet need to identify factors which can reverse this dysfunctional profile and restore their anti-tumorigenic potential. Activin-A is a pleiotropic cytokine, exerting a broad range of pro- or anti-inflammatory functions in different disease contexts, including allergic and autoimmune disorders and cancer. Given that activin-A exhibits a profound effect on CD4+ T cells in the airways and is elevated in lung cancer patients, we hypothesized that activin-A can effectively regulate anti-tumor immunity in lung cancer. Methods: To evaluate the effects of activin-A in the context of lung cancer, we utilized the OVA-expressing Lewis Lung Carcinoma mouse model as well as the B16F10 melanoma model of pulmonary metastases. The therapeutic potential of activin-A-treated lung tumor-infiltrating CD4+ T cells was evaluated in adoptive transfer experiments, using CD4-/--tumor bearing mice as recipients. In a reverse approach, we disrupted activin-A signaling on CD4+ T cells using an inducible model of CD4+ T cell-specific knockout of activin-A type I receptor. RNA-Sequencing analysis was performed to assess the transcriptional signature of these cells and the molecular mechanisms which mediate activin-A's function. In a translational approach, we validated activin-A's anti-tumorigenic properties using primary human tumor-infiltrating CD4+ T cells from lung cancer patients. Results: Administration of activin-A in lung tumor-bearing mice attenuated disease progression, an effect associated with heightened ratio of infiltrating effector to regulatory CD4+ T cells. Therapeutic transfer of lung tumor-infiltrating activin-A-treated CD4+ T cells, delayed tumor progression in CD4-/- recipients and enhanced T cell-mediated immunity. CD4+ T cells genetically unresponsive to activin-A, failed to elicit effective anti-tumor properties and displayed an exhausted molecular signature governed by the transcription factors Tox and Tox2. Of translational importance, treatment of activin-A on tumor-infiltrating CD4+ T cells from lung cancer patients augmented their immunostimulatory capacity towards autologous CD4+ and CD8+ T cells. Conclusions: In this study, we introduce activin-A as a novel immunomodulatory factor in the lung tumor microenvironment, which bestows exhausted CD4+ T cells with effector properties. Overall design: In this study we induced the formation of lung tumors in WT and transgenic mice, which specifically lack the expression of ALK4 on CD4+ T cells (CD4/ALK4-KO). CD4+ T cells which infiltrated the lung tumors from both WT and CD4ALK4-KO mice were isolated and RNA was extracted. 4 samples in total were analyzed, consisting of 2 biological replicates from each mouse strain. Lung tumor-infiltrating CD4+ T cells from WT mice were used as control samples and the respective samples from CD4/ALK4-KO mice comprised the treated group.