Efficient blockade of locally reciprocated tumor-macrophage signaling using a TAM-avid nanotherapy

Abstract

Interpreting how multicellular interactions in the tumor affect resistance pathways to BRAF and MEK1/2 MAPK inhibitors (MAPKi) remains a challenge. To investigate this, we profiled global ligand-receptor interactions among tumor and stromal/immune cells from biopsies of MAPK-driven disease. MAPKi increased tumor-associated macrophages (TAMs) in some patients, which correlated with poor clinical response, and MAPKi coamplified bidirectional tumor-TAM signaling via receptor tyrosine kinases (RTKs) including AXL, MERTK, and their ligand GAS6. In xenograft tumors, intravital microscopy simultaneously monitored in situ single-cell activities of multiple kinases downstream of RTKs, revealing MAPKi increased TAMs and enhanced bypass signaling in TAM-proximal tumor cells. As a proof-of-principle strategy to block this signaling, we developed a multi-RTK kinase inhibitor nanoformulation that accumulated in TAMs and delayed disease progression. Thus, bypass signaling can reciprocally amplify across nearby cell types, offering new opportunities for therapeutic design.

In vivo microscopy reveals macrophage polarization locally promotes coherent microtubule dynamics in migrating cancer cells

“…For track-based analyses sample sizes were not predetermined as all the tracks computationally determined were used for downstream analyses. Sample sizes for cells, tumors, or mice were chosen based on estimated effect sizes from prior studies with this xenograft model and in vitro cell culture experiments 19 , 20 , 23 , 24 , 64 . All experiments were performed with ≥2 independent replicates as described in the figure captions.…”

Macrophage imaging and subset analysis using single-cell RNA sequencing

“…Past clinical trials, including one that studied a small cohort of melanoma patients, have found correlation between MΦ infiltration and poor response to immune checkpoint blockade using the programmed death 1 (PD1) targeted monoclonal antibody (mAb) nivolumab [10]. Additionally, in a small study of 9 patients with melanoma, kinase inhibitor response correlated more negatively with the drug-induced accumulation of MΦ than any other immune cell-type assessed [11]. These instances of clinical correlations and many others suggest that MΦ quantification may be useful in predicting responses to a variety of different drugs [12].…”

“…IgG4, deglycosylated mAbs, Fc-null or Fc-effectorless mAbs) act instead to bind and block extracellular signal transmission [79]. FcγR2b is unique in that it has an ITIM (immunoreceptor tyrosine-based inhibition motif) domain in place of the activating ITAM (immunoreceptor tyrosine-based [11] using scRNAseq data GSE72056 [28], copyright 2020. B) Average expression values corresponding to single-cell data in A.…”

“…In the case of targeted mitogen activated protein kinase (MAPK) - extracellular related kinase (ERK) inhibition in Braf V600E cancers, inhibition of the MAPK/ERK pathway using a clinical MEK1/2 inhibitor enriched xenografts for TAM content, stimulated VEGF and growth factor production in MΦ, stimulated MΦ to more avidly accumulate nanoparticles, and therefore led to greater nanoparticle uptake in treated tumors ( Fig. 10 ) 11 . Analysis of these tumor cell populations by scRNAseq elucidated the complex ligand-receptor communication that occurs between tumor cells and MΦ, offering new avenues for therapeutic intervention.…”

“…In this patient cohort, expression of the target of nivolumab, an IgG4 anti-PD1 antibody, is primarily found in T-cells, while its inhibitory Fc receptor FcγR2b is primarily found in B-cells and myeloid cells, including MΦ. Figure adapted with permission from 11 using scRNAseq data GSE72056 28 , copyright 2020. B) Average expression values corresponding to single-cell data in A .…”