Type 2 immune responses are classically associated with parasite infections at barrier surfaces, and
evolved in part to repair the massive tissue damage that these maladies induce. However, the role of Type 2
immunity in cancer progression is understudied, despite the fact that many cancers occur at mucosal surfaces
that are primed to engage such responses upon tissue insult. Non-small cell lung carcinoma (NSCLC) is the
leading cause of cancer-related death worldwide. ¿PD-(L)1 immunotherapy has revolutionized care for NSCLC
patients, but its efficacy is limited by the immunosuppressive tumor microenvironment (TME) which is
predominantly populated by various myeloid cell subsets. Using single cell RNA-sequencing (scRNA-seq), we
recently mapped the immune landscape of the human and murine NSCLC TME. We identified several newfound
populations of myeloid cells that exhibited high transcriptional concordance across species. In both instances,
we found that myeloid cells within the TME specifically upregulated a transcriptional program driven by IL-4, a
prototypical Type 2 cytokine. Blockade of IL-4 strongly protected mice against orthotopic lung tumors.
Surprisingly, we found that IL-4-producing Th2 cells were essentially absent from the lung TME in mice and
humans. Instead, IL-4 was almost exclusively produced by basophils. Accordingly, antibody-mediated depletion
of basophils in vivo strongly reduced lung tumor development. Using mice with cell type-specific deletion of the
IL-4R¿¿ we found that granulocyte-monocyte progenitor (GMP)-derived cells were the dominant immune cells
responding to IL-4 to enhance tumor burden. Within the tumor, the overwhelming majority of these cells are
macrophages and neutrophils. Surprisingly, we also discovered that myeloid progenitors in BM directly sense
IL-4/IL-13 signaling during lung tumor development. Furthermore, GMP-specific deletion of IL-4R¿ enhanced
myeloid cell differentiation in response to lung tumors, preventing the so-called “emergency myelopoiesis” known
to fuel tumor growth.
Our central hypothesis is that basophil-derived IL-4 promotes NSCLC by controlling the development and
function of immunosuppressive myeloid cells. To address this, we first will identify signals from neoplastic cells
that activate basophils to produce IL-4 (Aim 1). Then, we will define how myeloid-intrinsic IL-4R¿ signaling
controls the immune response to NSCLC, both at the level of the TME and at the level of myeloid differentiation
in BM, and how these two arms synergize during ¿PD-1 immunotherapy (Aim 2). Finally, we will integrate our
findings from murine systems into the first human clinical trial of dupilumab, an FDA-approved IL-4R¿ blocking
antibody, in metastatic NSCLC patients who have not responded to immunotherapy and evaluate relevant
immunologic alterations. Collectively, our work will (i) define a novel axis controlling lung tumor development, (ii)
identify targets for therapeutic intervention, and (iii) reinforce a growing paradigm in which tumor signals instruct
the fates of developing myeloid cells to affect cancer outcome.