Blocking IFNAR1 inhibits multiple myeloma–driven Treg expansion and immunosuppression
Yawara Kawano, … , Jamil Azzi, Irene M. Ghobrial
Yawara Kawano, … , Jamil Azzi, Irene M. Ghobrial
Published March 20, 2018
Citation Information: J Clin Invest. 2018;128(6):2487-2499. https://doi.org/10.1172/JCI88169.
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Research Article Hematology Immunology

Blocking IFNAR1 inhibits multiple myeloma–driven Treg expansion and immunosuppression

Abstract

Despite significant advances in the treatment of multiple myeloma (MM), most patients succumb to disease progression. One of the major immunosuppressive mechanisms that is believed to play a role in myeloma progression is the expansion of regulatory T cells (Tregs). In this study, we demonstrate that myeloma cells drive Treg expansion and activation by secreting type 1 interferon (IFN). Blocking IFN α and β receptor 1 (IFNAR1) on Tregs significantly decreases both myeloma-associated Treg immunosuppressive function and myeloma progression. Using syngeneic transplantable murine myeloma models and bone marrow (BM) aspirates of MM patients, we found that Tregs were expanded and activated in the BM microenvironment at early stages of myeloma development. Selective depletion of Tregs led to a complete remission and prolonged survival in mice injected with myeloma cells. Further analysis of the interaction between myeloma cells and Tregs using gene sequencing and enrichment analysis uncovered a feedback loop, wherein myeloma-cell-secreted type 1 IFN induced proliferation and expansion of Tregs. By using IFNAR1-blocking antibody treatment and IFNAR1-knockout Tregs, we demonstrated a significant decrease in myeloma-associated Treg proliferation, which was associated with longer survival of myeloma-injected mice. Our results thus suggest that blocking type 1 IFN signaling represents a potential strategy to target immunosuppressive Treg function in MM.

Authors

Yawara Kawano, Oksana Zavidij, Jihye Park, Michele Moschetta, Katsutoshi Kokubun, Tarek H. Mouhieddine, Salomon Manier, Yuji Mishima, Naoka Murakami, Mark Bustoros, Romanos Sklavenitis Pistofidis, Mairead Reidy, Yu J. Shen, Mahshid Rahmat, Pavlo Lukyanchykov, Esilida Sula Karreci, Shokichi Tsukamoto, Jiantao Shi, Satoshi Takagi, Daisy Huynh, Antonio Sacco, Yu-Tzu Tai, Marta Chesi, P. Leif Bergsagel, Aldo M. Roccaro, Jamil Azzi, Irene M. Ghobrial

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Figure 7

Blocking IFNAR1 suppresses Treg expansion and myeloma progression.

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Blocking IFNAR1 suppresses Treg expansion and myeloma progression. (A) R...
(A) Representative FACS analysis of Ki-67 expression of Tregs expanded under coculture with Vk*MYC cells and IFNAR1 antibody (IFNAR1 Ab) or isotype control (isotype Ab). (B) Significant decrease of Ki-67 expression in Tregs cocultured with Vk*MYC and IFNAR1 Ab compared with those with isotype Ab. Average of experiments performed in triplicate is shown. The experiment was repeated 3 times. (C) Representative FACS analysis of Treg expansion assay with IFNAR1 Ab or isotype Ab coculture. Proportion of FOXP3+ cells in the CD4+ cells is shown. (D) Significant decrease of Treg proliferation by cells cocultured with Vk*MYC and IFNAR1 Ab compared with isotype Ab. Average of experiments performed in triplicate is shown. The experiment was repeated 3 times. (E) Non-Tregs (3 × 106) were injected with or without 1 × 106 C57BL/6 Tregs or IFNAR1-KO Tregs i.v. into Rag2-KO mice followed by Vk*MYC cell injection 5 days afterwards. (F) Kaplan-Meier curve showing survival of mice injected with C57BL/6 Tregs and CD3+ non-Tregs (WT Tregs + CD3+ non-Tregs) compared with mice injected with IFNAR1-KO Tregs and CD3+ non-Tregs (IFNAR1-KO Tregs + CD3+ non-Tregs) and only with CD3+ non-Tregs (n = 6/group). (G) Significant decrease of BM Tregs in the IFNAR1-KO group (IFNAR1 -KO Tregs + CD3+ non-Tregs) compared with wild-type group (n = 3/group) by FACS. (H) Representative FACS analysis of BM Tregs of mice transferred with IFNAR1-KO Tregs compared with mice transferred with wild-type Tregs. (I) FACS analysis of checkpoint-related molecules on BM Tregs obtained from mice injected with IFNAR1-KO Tregs and wild-type Tregs. Significant decrease of LAG3 was observed in BM Tregs obtained from mice injected with IFNAR1-KO mice (n = 3/group). P value determined by 2-tailed t test. Error bars indicate SD.