Gene expression data from 4T1 irradiated tumors treated with TGFbeta blockade

Here we tested the hypothesis that TGFβ hinders the ability of RT to promote anti-tumor immunity. Development of tumor-specific immunity was examined in a pre-clinical model of metastatic breast cancer. Mice bearing established 4T1 mouse mammary carcinoma treated with pan-isoform specific TGFβ neutralizing antibody, 1D11, showed significantly improved control of the irradiated tumor and non-irradiated metastases, but no effect in the absence of RT. Notably, whole tumor transcriptional analysis demonstrated the selective upregulation of genes associated with immune-mediated rejection only in tumors of mice treated with RT+TGFβ blockade. Mice treated with RT+TGFβ blockade exhibited cross-priming of CD8+ T cells producing IFNγ in response to three tumor-specific antigens in tumor-draining lymph nodes, which was not evident for single modality treatment. Analysis of the immune infiltrate in mouse tumors showed a significant increase in CD4+ and CD8+ T cells only in mice treated with the combination of RT+TGFβ blockade. Depletion of CD4+ or CD8+ T cells abrogated the therapeutic benefit of RT+TGFβ blockade. These data identify TGFβ as a master inhibitor of the ability of RT to generate an in situ tumor vaccine, which supports testing inhibition of TGFβ during radiotherapy to promote therapeutically effective anti-tumor immunity. We used genome-wide microarray to depict main biological processes responsibles for the therapeutic benefit of the combination ofTGF-beta blockade and local radiotherapy.