Neuropilin-1 identifies a subset of bone marrow Gr1-monocytes that can induce tumor vessel normalization and inhibit tumor growth

Alessandro Carrer, Silvia Moimas, Serena Zacchigna, Lucia Pattarini, Lorena Zentilin, Giulia Ruozi, Miguel Mano, Milena Sinigaglia, Federica Maione, Guido Serini, Enrico Giraudo, Federico Bussolino, Mauro Giacca

Research output: Contribution to journalArticlepeer-review


Improving tumor perfusion, thus tempering tumor-associated hypoxia, is known to impair cancer progression. Previous work from our laboratory has shown that VEGF-A165 and semaphorin 3A (Sema3A) promote vessel maturation through the recruitment of a population of circulating monocytes expressing the neuropilin-1 (Nrp1) receptor (Nrp1-expressing monocytes; NEM). Here, we define the characteristics of bone marrow NEMs and assess whether these cells might represent an exploitable tool to induce tumor vessel maturation. Gene expression signature and surface marker analysis have indicated that NEMs represent a specific subset of CD11b+ Nrp1+ Gr1- resident monocytes, distinctively recruited by Sema3A. NEMs were found to produce several factors involved in vessel maturation, including PDGFb, TGF-β, thrombospondin-1, and CXCL10; consistently, they were chemoattractive for vascular smooth muscle cells in vitro. When directly injected into growing tumors, NEMs, isolated either from the bone marrow or from Sema3A-expressing muscles, exerted antitumor activity despite having no direct effects on the proliferation of tumor cells. NEM inoculation specifically promoted mural cell coverage of tumor vessels and decreased vascular leakiness. Tumors treated with NEMs were smaller, better perfused and less hypoxic, and had a reduced level of activation of HIF-1α. We conclude that NEMs represent a novel, unique population of myeloid cells that, once inoculated into a tumor, induce tumor vessel normalization and inhibit tumor growth.

Original languageEnglish
Pages (from-to)6371-6381
Number of pages11
JournalCancer Research
Issue number24
Publication statusPublished - Dec 15 2012

ASJC Scopus subject areas

  • Cancer Research
  • Oncology


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