Cervical Cancer Evades the Host Immune System through the Inhibition of Type I Interferon and CXCL9 by LIF.

Purpose: Cervical cancer is a viral-associated tumor caused by the infection with the human papilloma virus. Cervical cancer is an immunogenic cancer that expresses viral antigens. Despite being immunogenic, cervical cancer does not fully respond to immune checkpoint inhibitors (ICI). LIF is a crucial cytokine in embryo implantation, involved in maternal tolerance that acts as an immunomodulatory factor in cancer. LIF is expressed in cervical cancer and high levels of LIF is associated with poor prognosis in cervical cancer.

Experimental Design: We evaluated the impact of LIF on the immune response to ICI using primary plasmocytoid dendritic cells (pDC) and macrophage cultures, syngeneic animals and patient-derived models that recapitulate the human tumor microenvironment.

Results: We found that the viral proteins E6 and E7 induce the expression of LIF via the NFκB pathway. The secreted LIF can then repress type I interferon expressed in pDCs and CXCL9 expressed in tumor-associated macrophages. Blockade of LIF promotes the induction of type I interferon and CXCL9 inducing the tumor infiltration of CD8 T cells. This results in the sensitization of the tumor to ICI. Importantly, we observed that patients with cervical cancer expressing high levels of LIF tend to be resistant to ICI.

Conclusions: Our data show that the HPV virus induces the expression of LIF to provide a selective advantage to the tumor cell by generating local immunosuppression via the repression of type I interferon and CXCL9. Combinatory treatment with blocking antibodies against LIF and ICI could be effective against cervical cancer expressing high levels of LIF.