Targeting FROUNT with disulfiram suppresses macrophage accumulation and its tumor-promoting properties

Yuya Terashima,Koji Ohnishi,Toshihiko Iwamoto ,Etsuko Toda,Hirofumi Rokutan,Ichio Shimada,Mitsuhiro Takeda,Hirotatsu Kojima,Akira Shimizu,Hiroaki Terasawa,Hirofumi Nakano,Takayoshi Okabe,Kana Kokubo,Francis H.w Shand ,Shiro Kanegasaki,Miki Ohira,Sana Yokoi,Ming Rong Zhang ,Ming Chen Chen ,Yoshihiro Komohara,Sosuke Yoshinaga,Meiji Itakura,Mikiya Otsuji,Hiroki Nagase,Yutaka Kofuku,Kazuhiro Okumura,Kouji Matsushima

doi:10.1038/s41467-020-14338-5

Abstract

Tumor-associated macrophages affect tumor progression and resistance to immune checkpoint therapy. Here, we identify the chemokine signal regulator FROUNT as a target to control tumor-associated macrophages. The low level FROUNT expression in patients with cancer correlates with better clinical outcomes. Frount-deficiency markedly reduces tumor progression and decreases macrophage tumor-promoting activity. FROUNT is highly expressed in macrophages, and its myeloid-specific deletion impairs tumor growth. Further, the anti-alcoholism drug disulfiram (DSF) acts as a potent inhibitor of FROUNT. DSF interferes with FROUNT-chemokine receptor interactions via direct binding to a specific site of the chemokine receptor-binding domain of FROUNT, leading to inhibition of macrophage responses. DSF monotherapy reduces tumor progression and decreases macrophage tumor-promoting activity, as seen in the case of Frount-deficiency. Moreover, co-treatment with DSF and an immune checkpoint antibody synergistically inhibits tumor growth. Thus, inhibition of FROUNT by DSF represents a promising strategy for macrophage-targeted cancer therapy.

Highlights

Tumor-associated macrophages affect tumor progression and resistance to immune checkpoint therapy
Considering the role of FROUNT as a common regulator of chemokine receptors CCR2 and CCR5, which have been implicated in tumor progression, we hypothesized that FROUNT expression levels affect clinical outcomes
When patients were divided into FROUNT-high (n = 20) and FROUNT-low groups (n = 20) (Fig. 1a), recurrence-free and total survival rates were significantly higher in the FROUNT-low group than the FROUNT-high group (Fig. 1b, c)

Summary

Introduction

Tumor-associated macrophages affect tumor progression and resistance to immune checkpoint therapy. Blockade of CCR2 or CCR5 has been shown to inhibit tumor progression in some animal models[11,12,13,16,17] Distinct in their chemokine usage, these receptors share a common binding region for FROUNT in the intracellular membrane-proximal C-terminal domain. Studies using clinical specimens and Frount-gfp reporter mice showed that FROUNT is highly expressed in macrophages, and Frount deficiency in mice decreased macrophage accumulation at the tumor site and impaired the tumor-promoting activity of macrophages. DSF reduced macrophage accumulation in the tumor, suppressed macrophage activity, increased the numbers of cytotoxic CD8+ T cells in the tumor when combined with the immune-checkpoint inhibitor anti-PD-1 antibody, and inhibited tumor growth and metastasis. Our findings suggest that regulating tumor-promoting macrophages by targeting FROUNT may be a safe and effective approach in cancer therapy

Methods

Results

Conclusion