Targeted inhibition of Aurora kinase A promotes immune checkpoint inhibition efficacy in human papillomavirus-driven cancers

Human papillomavirus (HPV)-driven cancers include head and neck squamous cell carcinoma and cervical cancer and represent approximately 5% of all cancer cases worldwide. Standard-of-care chemotherapy, radiotherapy, and immune checkpoint inhibitors (ICIs) are associated with adverse effects and limited responses in patients with HPV-driven cancers. The integration of targeted therapies with ICIs may improve outcomes. In a previous study, we demonstrated that Aurora kinase A (AURKA, Aurora A) inhibitors lead to apoptosis of human HPV-positive cancer cells in vitro and in vivo. Here, we explored the potential of Aurora A inhibition to enhance response to ICIs in immune-competent preclinical models of HPV-driven cancers.

Our study establishes the potential of Aurora A inhibition to sensitize HPV-positive tumors to ICIs, specifically anti-CTLA-4 treatment. This combination strategy resulted in enhanced antitumor efficacy, driven by systemic and intratumoral increases in CD8 T-cell responses and reduced immunosuppressive cell populations, specifically MDSCs. These findings offer insights into the synergistic effects of Aurora A inhibition and ICIs and argue for further investigation and optimization of this combination approach in HPV-driven cancers.

We assessed the induction of apoptosis, DNA damage, and immunogenic cell death (ICD) in response to treatment with the Aurora A inhibitor alisertib in vitro and antitumor efficacy of alisertib as a monotherapy and in combination with ICIs that inhibit programmed cell death protein-1 (PD-1) or cytotoxic T-lymphocyte associated protein 4 (CTLA-4) in murine HPV-positive immune-competent tumor models. In each treatment group, we determined the tumor growth kinetics and long-term survival and assessed the tumor immune microenvironment using polychromatic flow cytometry.

Aurora A inhibition induced apoptosis, DNA damage, and ICD in vitro in multiple human and murine HPV-positive cancer cell lines. Importantly, Aurora A inhibition induced selective apoptotic depletion of myeloid-derived suppressor cells (MDSCs). In vivo experiments demonstrated that the combination of alisertib with ICIs, specifically anti-CTLA4, resulted in improved survival outcomes by altering the tumor immune microenvironment. This combination enhanced CD8 T-cell infiltration and decreased the frequencies of MDSCs, whereas neither alisertib nor ICIs (anti-PD-1/anti-CTLA-4) alone showed such effects.