Background <p>Pancreatic ductal adenocarcinoma (PDAC) exhibits a profoundly immunosuppressive tumour microenvironment (TME) dominated by inflammatory monocytes (IMs) and tumour-associated macrophages (TAMs), which restrict adaptive immunity and drive resistance to immune checkpoint blockade (ICB). Recruitment of CCR2⁺ IMs by tumour-derived CCL2 is a central mechanism underlying TAM accumulation. Conventional gemcitabine (GEM) and small-molecule CCR2 inhibitors provide limited benefit due to poor intratumoural delivery, transient target engagement, and compensatory myeloid recruitment.</p> Methods <p>We engineered a CCR2-targeted nanotheranostic by conjugating a CCR2-binding peptide (ECL1i) and GEM onto ultrasmall copper nanoclusters (CuNCs-ECL1i-GEM; C-E-G). Therapeutic efficacy and immune remodelling were evaluated using orthotopic subcutaneous and the autochthonous PDAC mouse models model, using scRNAseq, flow cytometry, multiplex immunohistochemistry, and in vitro functional assays.</p> Results <p>C-E-G exhibited robust tumour accumulation and selectively eliminated CCR2⁺ TAMs without systemic myelotoxicity, while durably reprogramming residual macrophages. Mechanistically, C-E-G induced the emergence of an immunostimulatory CCRL2⁺ TAM subset through true macrophage repolarization rather than monocyte replacement. CCRL2⁺ TAMs accumulated intratumoural chemerin, upregulated antigen-presentation and co-stimulatory programs, and were essential for CD8⁺ T-cell recruitment and activation. Genetic and orthotopic studies confirmed their CCR2-independent origin and requirement for tumour control. C-E-G remodelled the TME toward a lymphocyte-permissive inflammatory state and synergized with ICB to induce complete tumour regression and prolong survival in KPPC mice.</p> Conclusions <p>CCR2-targeted cytotoxic nanotherapy eliminates immunosuppressive CCR2 + TAMs, reprograms the macrophage landscape including CCRL2⁺ TAMs, and unlocks durable anti-tumour immunity in PDAC, supporting translational development of this strategy.</p>

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Therapeutic reprogramming of tumour-associated macrophages in pancreatic cancer using a cytotoxic CCR2-targeted nanotheranostic

  • Vikas Kumar Somani,
  • Xiaohui Zhang,
  • Timothy Hung-Po Chen,
  • Ashenafi Bulle,
  • Sapana Bansod,
  • Lin Li,
  • Yutong Geng,
  • Liang-I Kang,
  • Gyu Seong Heo,
  • Hannah Luehmann,
  • Yuena Zhang,
  • Muhammad A. Saeed,
  • Kory J. Lavine,
  • David G. DeNardo,
  • Russell K. Pachynski,
  • Yongjian Liu,
  • Kian-Huat Lim

摘要

Background

Pancreatic ductal adenocarcinoma (PDAC) exhibits a profoundly immunosuppressive tumour microenvironment (TME) dominated by inflammatory monocytes (IMs) and tumour-associated macrophages (TAMs), which restrict adaptive immunity and drive resistance to immune checkpoint blockade (ICB). Recruitment of CCR2⁺ IMs by tumour-derived CCL2 is a central mechanism underlying TAM accumulation. Conventional gemcitabine (GEM) and small-molecule CCR2 inhibitors provide limited benefit due to poor intratumoural delivery, transient target engagement, and compensatory myeloid recruitment.

Methods

We engineered a CCR2-targeted nanotheranostic by conjugating a CCR2-binding peptide (ECL1i) and GEM onto ultrasmall copper nanoclusters (CuNCs-ECL1i-GEM; C-E-G). Therapeutic efficacy and immune remodelling were evaluated using orthotopic subcutaneous and the autochthonous PDAC mouse models model, using scRNAseq, flow cytometry, multiplex immunohistochemistry, and in vitro functional assays.

Results

C-E-G exhibited robust tumour accumulation and selectively eliminated CCR2⁺ TAMs without systemic myelotoxicity, while durably reprogramming residual macrophages. Mechanistically, C-E-G induced the emergence of an immunostimulatory CCRL2⁺ TAM subset through true macrophage repolarization rather than monocyte replacement. CCRL2⁺ TAMs accumulated intratumoural chemerin, upregulated antigen-presentation and co-stimulatory programs, and were essential for CD8⁺ T-cell recruitment and activation. Genetic and orthotopic studies confirmed their CCR2-independent origin and requirement for tumour control. C-E-G remodelled the TME toward a lymphocyte-permissive inflammatory state and synergized with ICB to induce complete tumour regression and prolong survival in KPPC mice.

Conclusions

CCR2-targeted cytotoxic nanotherapy eliminates immunosuppressive CCR2 + TAMs, reprograms the macrophage landscape including CCRL2⁺ TAMs, and unlocks durable anti-tumour immunity in PDAC, supporting translational development of this strategy.