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  2. Enhancing immunotherapy efficacy in NSCLC through the combined use of phenelzine and Akkermansia muciniphila to regulate gut microbial metabolite 5-HIAA

Enhancing immunotherapy efficacy in NSCLC through the combined use of phenelzine and Akkermansia muciniphila to regulate gut microbial metabolite 5-HIAA

  • J Immunother Cancer. 2025 Sep 10;13(9):e011831. doi: 10.1136/jitc-2025-011831.
Shilong Sun # 1 2 Longhao Wang # 3 Kang Cui # 4 Yuchao Ding 1 Yujie Wei 1 Yuanyuan Zheng 1 5 Zhibo Shen 5 Lili Zhu 1 Yaqi Yang 1 Pu Yu 4 Yiqiong Song 1 Ke Chao 1 Yixing Zhang 1 Yahao Ge 1 Wenxuan Ji 1 Chunwei Li 1 Gautam Sethi 6 Lifeng Li 7 8 9 Jie Zhao 7 2
Affiliations

Affiliations

  • 1 National Engineering Laboratory for Internet Medical Systems and Applications, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China.
  • 2 Department of Pharmacy, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China.
  • 3 Department of Oncology, Henan Provincial People's Hospital, Zhengzhou, Henan, China.
  • 4 Department of Oncology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China.
  • 5 Department of Radiation Oncology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China.
  • 6 Department of Pharmacology, National University of Singapore, Singapore.
  • 7 National Engineering Laboratory for Internet Medical Systems and Applications, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China zhaojie@zzu.edu.cn lilifeng0317@163.com.
  • 8 Cancer Center, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China.
  • 9 Hospital of Traditional Chinese Medicine of Xinjiang Uygur Autonomous Region, Uygur Autonomous Region, Xinjiang, China.
  • # Contributed equally.
Abstract

Background: Improving the efficacy of anti-programmed death 1 (PD-1) monoclonal antibody (mAb) therapy remains a major challenge for Cancer Immunotherapy in non-small cell lung Cancer (NSCLC). Gut microbial metabolites can influence immunotherapy efficacy.

Methods: ELISA was used to compare the serum 5-hydroxyindoleacetic acid (5-HIAA) level in patients with NSCLC. Humanized mice were constructed to observe the effect of 5-HIAA on immunotherapy. RNA-seq and flow cytometry were used to analyze the effect of 5-HIAA on tumor-infiltrating lymphocytes. The effects of phenelzine (Phe) and Akkermansia muciniphila (AKK) on 5-HIAA synthesis, antitumor immunity and immunotherapy efficacy were analyzed. Finally, the synergistic effect of Phe combined with AKK on anti-PD-1 mAb was observed.

Results: Here we found that 5-HIAA, which is regulated by gut microbiota, has increased concentrations in the serum of non-responders to immunotherapy. Supplementation of 5-HIAA inhibited the efficacy of anti-PD-1 mAb and tumor infiltration of CD8+ T cells. The use of Monoamine Oxidase Inhibitor (MAO-I) Phe inhibited the synthesis of 5-HIAA, then improved the efficacy of anti-PD-1 mAb. In addition, supplementation of AKK can also decrease 5-HIAA in serum. Finally, the combination of Phe and AKK maximally inhibited 5-HIAA synthesis and improved immunotherapy efficacy.

Conclusions: Our investigations reveal that alterations in gut microbial composition leading to increased 5-HIAA synthesis can negatively impact CD8+ T cell functionality and the success of immunotherapy. The combination of Phe and AKK supplementation holds potential for optimizing immunotherapy efficacy.

Keywords

Immunotherapy; Lung Cancer.

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