ATM-mediated DNA damage signals mediate immune escape through integrin-αvß3-dependent mechanisms.

ABSTRACT

Although the tumor microenvironment plays a critical role in tumor progression and metastasis, the relationship between chemotherapy resistance and modulation of the tumor microenvironment remains unclear. Here, we report a novel mechanism showing how constitutive DNA damage signals in therapy-resistant tumor cells suppress antitumor immunity in an integrin-αvß3-dependent manner. Integrin-αvß3 was upregulated on various therapy-resistant tumor cells through chronic activation of ATM/Chk2-and NFκB-mediated pathways. Inhibiting tumor-specific expression of integrin-αvß3 improved therapeutic responses to anticancer drugs by stimulating endogenous host immune systems. Mechanistic investigations revealed that tumor-specific integrin-αvß3 expression targeted dendritic cells, facilitating their ability to phagocytose viable therapy-resistant tumor cells and thereby impaired their ability to cross-prime antigen-specific T lymphocytes. Together, our results clarify the detrimental effects of constitutive DNA damage signals to chemosensitivity and antitumor immunity. Furthermore, these findings suggest that integrin-αvß3 targeting may benefit patients' refractory to current anticancer regimens by defeating DNA damage signaling-induced immune escape.