Adaptive immunity is required for durable responses to alectinib in murine models of EML4-ALK lung cancer

Abstract

PPurpose: Lung cancers bearing oncogenic EML4-ALK fusions respond to targeted tyrosine kinase inhibitors (TKIs; e.g. alectinib), with variation in the degree of shrinkage and duration of treatment (DOT). We previously demonstrated a positive association of a TKI-induced interferon gamma (IFNgamma) transcriptional response with DOT in EGFR-mutant lung cancers. Herein, we used murine models of EML4-ALK lung cancer to test a role for host immunity in the therapeutic response to alectinib. Experimental Design: Three murine EML4-ALK cell lines (EA1, EA2, EA3) were implanted orthotopically into the lungs of immunocompetent and immunodeficient mice and treated with alectinib. Tumor volumes were serially measured by micro CT. Immune cell content was measured by flow cytometry, multispectral immunofluorescence and CyTOF. Transcriptional responses to alectinib were assessed by RNAseq and secreted chemokines were measured by ELISA. Results: All cell lines were sensitive to alectinib in vitro. EA1 and EA3 tumors retained residual disease that rapidly progressed upon termination of treatment while EA2 tumors were eliminated by TKI treatment. Alectinib induced inflammatory transcriptional programs and multiple chemokines in all cell lines while untreated tumors exhibited distinct baseline chemokine expression patterns and content of CD8+ T cells and myeloid subsets. When propagated in immune-deficient mice, all three cell line-derived lung tumor models exhibited significant shrinkage followed by prompt progression despite continuous alectinib treatment. Conclusions: The findings support an hypothesis that host and TKI-stimulated production of chemokines by tumor cells promotes functional engagement of adaptive immune cells within the tumor microenvironment that enhances the durability and depth of TKI response.

Novel EGFR-Mutant Mouse Models of Lung Adenocarcinoma Reveal Adaptive Immunity Requirement for Durable Osimertinib Response

“…Using these murine EGFR mutant cell lines, we present strong evidence for adaptive immunity as a requirement for durable inhibition of orthotopic tumors by osimertinib (Figure 4). In this regard, our present study adds to a growing body of evidence supporting host immunity as a contributor to therapeutic efficacy of oncogene-targeted agents [20][21][22][23][24][25][26][27]48]. We previously reported that the degree of induction of the IFNg Hallmark response as well as a T cell signature [49] in on-treatment biopsies associate with the duration of therapeutic benefit in patients bearing EGFR mutant lung cancers [18].…”

Evaluation of KRASG12C Inhibitor Responses in Novel Murine KRASG12C Lung Cancer Cell Line Models

“…Canon et al demonstrated the involvement of anti-tumor immunity in the therapeutic response to sotorasib (AMG-510) using the CT-26 cell line model 26 . Also, our own studies with murine EML4-ALK-driven cell lines demonstrate a requirement for adaptive immunity for durable responses to the ALK inhibitor, alectinib 19 . Current understanding surrounding the depth and duration of response to oncogene-targeted inhibitors suggests that the extent to which chemokine induction occurs with oncogene-specific therapies associates with the degree of response, as EGFR mutant lung cancer patients exhibiting greater interferon γ transcriptional responses to TKIs presented with longer progression-free survival.…”

“…5), indicating a role for adaptive immunity for full therapeutic efficacy. In fact, a role for innate and adaptive immunity in contributing to anti-tumor responses to oncogene-targeted therapeutics is documented in the literature [16][17][18][19][20][21][22]26,27 . In addition, our data show that KRAS G12C inhibitors variably induce chemokines (CXCL10) capable of recruiting anti-tumorigenic immune cells such as NK, CD8 T, and dendritic cells into the TME, which is exacerbated in combination with SHP2 inhibitor (Fig.…”

“…Our lab and others have shown the importance of innate and adaptive immunity in driving pre-clinical and clinical responses to oncogene-targeted therapies [16][17][18][19][20][21][22] . Thus, comprehensive assessment of the therapeutic potential of oncogene-targeted agents requires immune competent murine models.…”

Upregulation of complement proteins in lung cancer cells mediates tumor progression

“…We have previously demonstrated that responsiveness to IFNγ and induction of MHCII in the tumor cells are important determinants of response to anti-PD-1 therapy in KRas-driven lung tumors ( 15 , 16 ). Interactions with the immune system also appears critical in mediating the response to tyrosine kinase inhibitors in ALK positive lung cancer ( 46 ). Similarly, common pathways that were downregulated in all four cell lines, including G2M checkpoint and E2F targets, suggest that the cancer cells grow more slowly in vivo , presumably due to signals originating from the TME inhibiting proliferation.…”