Targeting the ERβ/HER Oncogenic Network in <i>KRAS</i> Mutant Lung Cancer Modulates the Tumor Microenvironment and Is Synergistic with Sequential Immunotherapy
High ERβ/HER oncogenic signaling defines lung tumors with an aggressive biology. We previously showed that combining the anti-estrogen fulvestrant with the pan-HER inhibitor dacomitinib reduced ER/HER crosstalk and produced synergistic anti-tumor effects in immunocompromised lung cancer models, incl...
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2021-12-01
|
| Series: | International Journal of Molecular Sciences |
| Subjects: | |
| Online Access: | https://www.mdpi.com/1422-0067/23/1/81 |
| Summary: | High ERβ/HER oncogenic signaling defines lung tumors with an aggressive biology. We previously showed that combining the anti-estrogen fulvestrant with the pan-HER inhibitor dacomitinib reduced ER/HER crosstalk and produced synergistic anti-tumor effects in immunocompromised lung cancer models, including <i>KRAS</i> mutant adenocarcinoma. How this combination affects the tumor microenvironment (TME) is not known. We evaluated the effects of fulvestrant and dacomitinib on murine bone marrow-derived macrophages (BMDMs) and CD8+ T cells, and tested the efficacy of the combination in vivo, using the <i>KRAS</i> mutant syngeneic lung adenocarcinoma model, FVBW-17. While this combination synergistically inhibited proliferation of FVBW-17 cells, it had unwanted effects on immune cells, by reducing CD8+ T cell activity and phagocytosis in BMDMs and inducing PD-1. The effects were largely attributed to dacomitinib, which caused downregulation of Src family kinases and Syk in immune cells. In a subcutaneous flank model, the combination induced an inflamed TME with increased myeloid cells and CD8+ T cells and enhanced PD-1 expression in the splenic compartment. Concomitant administration of anti-PD-1 antibody with fulvestrant and dacomitinib was more efficacious than fulvestrant plus dacomitinib alone. Administering anti-PD-1 sequentially after fulvestrant plus dacomitinib was synergistic, with a two-fold greater tumor inhibitory effect compared to concomitant therapy, in both the flank model and in a lung metastasis model. Sequential triple therapy has potential for treating lung cancer that shows limited response to current therapies, such as <i>KRAS</i> mutant lung adenocarcinoma. |
|---|---|
| ISSN: | 1661-6596 1422-0067 |