CD70 as a critical mediator of tumor progression and immunosuppression in gliomas.

Abstract

18 Background: For malignant gliomas, current treatment modalities are rarely curative, necessitating development of novel therapies. Cancer immunotherapy has represented one of the most promising new treatment strategies for patients with gliomas based on the evidence that patients with brain tumors are able to mount immune responses against the autologous tumors. However, very few tumor specific targets have been discovered in this malignancy. Thus, identifying clinical useful targets for immunotherapeutic approaches is desperately needed. Methods: CD70 expression was tested from primary GBM and low grade gliomas patient tissues. CD70 gene expression and clinical outcomes were culled from TCGA datasets. CD70 inducing CD8 T cells death was performed by flowcytometry. Results: We demonstrate that CD70, a member of the TNF ligand family, was constitutively overexpressed by primary IDH-wild-type LGG and GBMs with mesenchymal gene signatures. Elevated CD70 expression was also found in recurrent tumors and correlated with tumor progression and poor survival outcome in LGGs and GBMs. CD70 was shown to be directly involved in tumor-chemokine production and associated with sustained T regulatory cells in tumor. Importantly, CD70 played a role inducing CD8+T- specific cell death via engagement of the EREG-EGFR axis in glioma. Conclusions: CD70 is a multi-pronged modulator of immunosuppression in gliomas and enhances tumor progression.