title: Reprogramming the lung microenvironment by inhaled immunotherapy fosters immune destruction of tumor.
abstract: Due to their constant exposure to inhaled antigens, lungs represent a particularly immunosuppressive environment that limits excessive immune responses; however, cancer cells can exploit this unique environment for their growth. We previously described the ability of aerosolized CpG-ODN combined with Poly(I:C) (TLR9 and TLR3 agonists, respectively) to promote antitumor immunity in a B16 melanoma lung metastasis model. Here, we explored the possibility of improving the therapeutic efficacy of TLR9/TLR3 agonist combinations by including in the inhalant either an antibody directed to both Ly6G and Ly6C markers to locally deplete myeloid-derived suppressive cells (MDSCs) or IFNα to directly activate the natural killer (NK) and macrophage innate immune cells in the lung. Addition of nebulized anti-MDSC antibody RB6-8C5 to aerosolized CpG-ODN/Poly(I:C) resulted in reduced mRNA levels of immunsuppressive molecules (IL10, Arg-1, and Nos2), increased activation of resident NK cells and improved treatment outcome, with a significant reduction in established B16 melanoma lung metastases compared to treatment with CpG-ODN/Poly(I:C) alone. Likewise, addition of aerosolized IFNα led to increased mRNA levels of proinflammatory cytokines (IL15 and IFNγ) in the lung and recruitment of highly activated NK cells, with no evident signs of toxicity and with a significantly improved antitumor effect as compared with aerosolized CpG-ODN/Poly(I:C). Combining both IFNα and RB6-8C5 with CpG-ODN/Poly(I:C) did not produce an additive effect compared to IFNα + CpG-ODN/Poly(I:C) or RB6-8C5 + CpG-ODN/Poly(I:C). Our results indicate that the inhalation therapy is a feasible and non-invasive strategy to deliver immunodulatory molecules, including antibodies and cytokines that reprogram the lung tumor microenvironment to foster immune destruction of tumors.
authors.affiliation: Dipartimento di Scienze Biomediche per la Salute, Università degli Studi di Milano, Milan, Italy; Molecular Targeting Unit, Milan, Italy.
authors.forename: Valentino
authors.initials: V
authors.lastname: Le Noci
authors.affiliation: Dipartimento di Scienze Biomediche per la Salute, Università degli Studi di Milano, Milan, Italy; Molecular Targeting Unit, Milan, Italy.
authors.forename: Michele
authors.initials: M
authors.lastname: Sommariva
authors.affiliation: Molecular Pharmacology Unit, Fondazione IRCCS Istituto Nazionale dei Tumori , Milan, Italy.
authors.forename: Monica
authors.initials: M
authors.lastname: Tortoreto
authors.affiliation: Molecular Pharmacology Unit, Fondazione IRCCS Istituto Nazionale dei Tumori , Milan, Italy.
authors.forename: Nadia
authors.initials: N
authors.lastname: Zaffaroni
authors.affiliation: Molecular Targeting Unit , Milan, Italy.
authors.forename: Manuela
authors.initials: M
authors.lastname: Campiglio
authors.affiliation: Molecular Targeting Unit , Milan, Italy.
authors.forename: Elda
authors.initials: E
authors.lastname: Tagliabue
authors.affiliation: Dipartimento di Scienze Biomediche per la Salute, Università degli Studi di Milano, Milan, Italy; Molecular Targeting Unit, Milan, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Balsari
authors.affiliation: Dipartimento di Scienze Biomediche per la Salute, Università degli Studi di Milano , Milan, Italy.
authors.forename: Lucia
authors.initials: L
authors.lastname: Sfondrini
keywords: IFNα; inhalation therapy; TLR agonists; lung microenvironment; tumor