Targeting RARγ Decreases Immunosuppressive Macrophage Polarization and Reduces Tumor Growth

Tumor-associated macrophages (TAMs) play a critical role in the tumor microenvironment (TME), interacting with cancer cells and other components to promote tumor growth. Given the influence of TAMs on tumor progression and resistance to therapy, regulating the activity of these macrophages is crucia...

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Main Authors: Jihyeon Park, Jisun Oh, Sang-Hyun Min, Ji Hoon Yu, Jong-Sup Bae, Hui-Jeon Jeon
Format: Article
Language:English
Published: MDPI AG 2025-07-01
Series:Molecules
Subjects:
Online Access:https://www.mdpi.com/1420-3049/30/15/3099
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author Jihyeon Park
Jisun Oh
Sang-Hyun Min
Ji Hoon Yu
Jong-Sup Bae
Hui-Jeon Jeon
author_facet Jihyeon Park
Jisun Oh
Sang-Hyun Min
Ji Hoon Yu
Jong-Sup Bae
Hui-Jeon Jeon
author_sort Jihyeon Park
collection DOAJ
description Tumor-associated macrophages (TAMs) play a critical role in the tumor microenvironment (TME), interacting with cancer cells and other components to promote tumor growth. Given the influence of TAMs on tumor progression and resistance to therapy, regulating the activity of these macrophages is crucial for improving cancer treatment outcomes. TAMs often exhibit immunosuppressive phenotypes (commonly referred to as M2-like macrophages), which suppress immune responses and contribute to drug resistance. Therefore, inhibiting immunosuppressive polarization offers a promising strategy to impede tumor growth. This study revealed retinoic acid receptor gamma (RARγ), a nuclear receptor, as a key regulator of immunosuppressive polarization in THP-1 macrophages. Indeed, the inhibition of RARγ, either by a small molecule or gene silencing, significantly reduced the expression of immunosuppressive macrophage markers. In a three-dimensional tumor spheroid model, immunosuppressive macrophages enhanced the proliferation of HCT116 colorectal cancer cells, which was significantly hindered by RARγ inhibition. These findings suggest that targeting RARγ reprograms immunosuppressive macrophages and mitigates the tumor-promoting effects of TAMs, highlighting RARγ as a promising therapeutic target for developing novel anti-cancer strategies.
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spelling doaj-art-5b95147fa4b8498189e3d3f5b48e2ea92025-08-20T03:02:55ZengMDPI AGMolecules1420-30492025-07-013015309910.3390/molecules30153099Targeting RARγ Decreases Immunosuppressive Macrophage Polarization and Reduces Tumor GrowthJihyeon Park0Jisun Oh1Sang-Hyun Min2Ji Hoon Yu3Jong-Sup Bae4Hui-Jeon Jeon5College of Pharmacy, Kyungpook National University, Daegu 41566, Republic of KoreaNew Drug Development Center, Daegu-Gyeongbuk Medical Innovation Foundation (K-MEDI hub), Daegu 41061, Republic of KoreaDepartment of Innovative Pharmaceutical Sciences, Kyungpook National University, Daegu 41566, Republic of KoreaNew Drug Development Center, Daegu-Gyeongbuk Medical Innovation Foundation (K-MEDI hub), Daegu 41061, Republic of KoreaCollege of Pharmacy, Kyungpook National University, Daegu 41566, Republic of KoreaNew Drug Development Center, Daegu-Gyeongbuk Medical Innovation Foundation (K-MEDI hub), Daegu 41061, Republic of KoreaTumor-associated macrophages (TAMs) play a critical role in the tumor microenvironment (TME), interacting with cancer cells and other components to promote tumor growth. Given the influence of TAMs on tumor progression and resistance to therapy, regulating the activity of these macrophages is crucial for improving cancer treatment outcomes. TAMs often exhibit immunosuppressive phenotypes (commonly referred to as M2-like macrophages), which suppress immune responses and contribute to drug resistance. Therefore, inhibiting immunosuppressive polarization offers a promising strategy to impede tumor growth. This study revealed retinoic acid receptor gamma (RARγ), a nuclear receptor, as a key regulator of immunosuppressive polarization in THP-1 macrophages. Indeed, the inhibition of RARγ, either by a small molecule or gene silencing, significantly reduced the expression of immunosuppressive macrophage markers. In a three-dimensional tumor spheroid model, immunosuppressive macrophages enhanced the proliferation of HCT116 colorectal cancer cells, which was significantly hindered by RARγ inhibition. These findings suggest that targeting RARγ reprograms immunosuppressive macrophages and mitigates the tumor-promoting effects of TAMs, highlighting RARγ as a promising therapeutic target for developing novel anti-cancer strategies.https://www.mdpi.com/1420-3049/30/15/3099tumor microenvironmenttumor-associated macrophagesM2 polarizationretinoic acid receptor gammatherapeutic target
spellingShingle Jihyeon Park
Jisun Oh
Sang-Hyun Min
Ji Hoon Yu
Jong-Sup Bae
Hui-Jeon Jeon
Targeting RARγ Decreases Immunosuppressive Macrophage Polarization and Reduces Tumor Growth
Molecules
tumor microenvironment
tumor-associated macrophages
M2 polarization
retinoic acid receptor gamma
therapeutic target
title Targeting RARγ Decreases Immunosuppressive Macrophage Polarization and Reduces Tumor Growth
title_full Targeting RARγ Decreases Immunosuppressive Macrophage Polarization and Reduces Tumor Growth
title_fullStr Targeting RARγ Decreases Immunosuppressive Macrophage Polarization and Reduces Tumor Growth
title_full_unstemmed Targeting RARγ Decreases Immunosuppressive Macrophage Polarization and Reduces Tumor Growth
title_short Targeting RARγ Decreases Immunosuppressive Macrophage Polarization and Reduces Tumor Growth
title_sort targeting rarγ decreases immunosuppressive macrophage polarization and reduces tumor growth
topic tumor microenvironment
tumor-associated macrophages
M2 polarization
retinoic acid receptor gamma
therapeutic target
url https://www.mdpi.com/1420-3049/30/15/3099
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