Theranostics 2018; 8(22):6307-6321. doi:10.7150/thno.29746

Research Paper

Anti-tumor macrophages activated by ferumoxytol combined or surface-functionalized with the TLR3 agonist poly (I : C) promote melanoma regression

Jiaojiao zhao1, Zhengkui Zhang2, Yaxian Xue1, Guoqun Wang3, Yuan Cheng4, Yuchen Pan1, Shuli Zhao5✉, Yayi Hou1,6✉

1. The State Key Laboratory of Pharmaceutical Biotechnology, Division of Immunology, Medical School, Nanjing University, Nanjing 210093, PR China
2. MOE Key Laboratory of High Performance Polymer Materials and Technology, Department of Polymer Science & Engineering, College of Chemistry & Chemical Engineering, and Jiangsu Key Laboratory for Nanotechnology, Nanjing University , Nanjing, 210093, PR China
3. Department of Oncology, First Affiliated Hospital, Nanjing Medical University, Nanjing 211166, PR China
4. Department of Biomedical Engineering, College of Engineering and Applied Sciences, Nanjing National Laboratory of Microstructures, Nanjing University, Nanjing, Jiangsu 210093, PR China
5. General Clinical Research Center, Nanjing First Hospital, Nanjing Medical University, Nanjing 210006, PR China
6. Jiangsu Key Laboratory of Molecular Medicine, Nanjing University, Nanjing 210093, PR China

Abstract

Macrophages orchestrate inflammation and control the promotion or inhibition of tumors and metastasis. Ferumoxytol (FMT), a clinically approved iron oxide nanoparticle, possesses anti-tumor therapeutic potential by inducing pro-inflammatory macrophage polarization. Toll-like receptor 3 (TLR3) activation also potently enhances the anti-tumor response of immune cells. Herein, the anti-tumor potential of macrophages harnessed by FMT combined with the TLR3 agonist, poly (I:C) (PIC), and FP-NPs (nanoparticles composed of amino-modified FMT (FMT-NH2) surface functionalized with PIC) was explored.

Methods: Proliferation of B16F10 cells co-cultured with macrophages was measured using immunofluorescence or flow cytometry (FCM). Phagocytosis was analyzed using FCM and fluorescence imaging. FP-NPs were prepared through electrostatic interactions and their properties were characterized using dynamic light scattering, transmission electron microscopy, and gel retardation assay. Anti-tumor and anti-metastasis effects were evaluated in B16F10 tumor-bearing mice, and tumor-infiltrating immunocytes were detected by immunofluorescence staining and FCM.

Results: FMT, PIC, or the combination of both hardly impaired B16F10 cell viability. However, FMT combined with PIC synergistically inhibited their proliferation by shifting macrophages to a tumoricidal phenotype with upregulated TNF-α and iNOS, increased NO secretion and augmented phagocytosis induced by NOX2-derived ROS in vitro. Combined treatment with FMT/PIC and FMT-NH2/PIC respectively resulted in primary melanoma regression and alleviated pulmonary metastasis with elevated pro-inflammatory macrophage infiltration and upregulation of pro-inflammatory genes in vivo. In comparison, FP-NPs with properties of internalization by macrophages and accumulation in the lung produced a more pronounced anti-metastatic effect accompanied with decreased myeloid-derived suppressor cells, and tumor-associated macrophages shifted to M1 phenotype. In vitro mechanistic studies revealed that FP-NPs nanoparticles barely affected B16F10 cell viability, but specifically retarded their growth by steering macrophages to M1 phenotype through NF-κB signaling.

Conclusion: FMT synergized with the TLR3 agonist PIC either in combination or as a nano-composition to induce macrophage activation for primary and metastatic melanoma regression, and the nano-composition of FP-NPs exhibited a more superior anti-metastatic efficacy.

Keywords: macrophage, ferumoxytol, poly (I : C), FP-NPs, melanoma

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How to cite this article:
zhao J, Zhang Z, Xue Y, Wang G, Cheng Y, Pan Y, Zhao S, Hou Y. Anti-tumor macrophages activated by ferumoxytol combined or surface-functionalized with the TLR3 agonist poly (I : C) promote melanoma regression. Theranostics 2018; 8(22):6307-6321. doi:10.7150/thno.29746. Available from http://www.thno.org/v08p6307.htm