Immunosurveillance constitutes the first step of cancer immunoediting in which developing malignant lesions are eliminated by anti-tumorigenic immune cells. However, the mechanisms by which neoplastic cells induce an immunosuppressive state to evade the immune response are still unclear. The transcription factor Stat3 has been implicated in breast carcinogenesis and tumor immunosuppression in advanced disease, but its involvement in early disease development has not been established. Here, we genetically ablated Stat3 in the tumor epithelia of the inducible PyVmT mammary tumor model and found that Stat3-deficient mice recapitulated the three phases of immunoediting: elimination, equilibrium, and escape. Pathological analyses revealed that Stat3-deficient mice initially formed hyperplastic and early adenoma-like lesions that later completely regressed, thereby preventing the emergence of mammary tumors in the majority of animals. Furthermore, tumor regression was correlated with massive immune infiltration into the Stat3-deficient lesions, leading to their elimination. In a minority of animals, focal, non-metastatic Stat3-deficient mammary tumors escaped immunosurveillance after a long latency or equilibrium period. Taken together, our findings suggest that tumor epithelial expression of Stat3 plays a critical role in promoting an immunosuppressive tumor microenvironment during breast tumor initiation and progression, and prompt further investigation of Stat3 inhibitory strategies that may reactivate the immunosurveillance program.
STAT3 Establishes an Immunosuppressive Microenvironment during the Early Stages of Breast Carcinogenesis to Promote Tumor Growth and Metastasis.
Age, Specimen part
View SamplesIn order to investigate what signalling pathways are turned on by tenascin-C, we generated Mouse Embryonic Fibroblasts (MEFs) deficient for tenascin-C and compared their gene expression profile to MEFs proficient for tenascin-C.
Tenascin-C triggers fibrin accumulation by downregulation of tissue plasminogen activator.
Specimen part
View SamplesCelastrol has been shown to sensitize leptin receptor signaling and reduce ER stress. Current microarray data provide the gene expression profile in mouse embryonic fibroblasts (MEFs) after Celastrol treatment compared with control.
Withaferin A is a leptin sensitizer with strong antidiabetic properties in mice.
Specimen part, Treatment
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