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Construction and Mechanism of IL-15-Based Coactivated Polymeric Micelles for NK Cell Immunotherapy
Dongyan Shao1, Ting Bai2, Bobo Zhu1
1Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi'an, 710072, China.
Abstract:
Natural killer (NK) cells are an important contributor to cancer immunotherapy, but their antitumor efficacy remains suboptimal. While cytokine-based priming shows promise in enhancing NK-cell activity, its clinical translation faces many challenges, including coactivation of multiple cytokines, poor pharmacokinetics, and limited mechanistic understanding. Here, this work develops a polymeric micelle-based IL-15/IL-2 codelivery system (IL-15/2-PEG-PTMC) for NK-cell activation. In vivo studies demonstrate that half-life of IL-15 and IL-2 and the recruitment of NK cell within tumor tissue are significantly increased after PEG-PTMC loading. Coupled with the coactivation effect of IL-15 and IL-2 conferred by this system, it noticeably delays the growth of tumors compared to conventional NK-cell activation approach, that is free IL-15 and IL-2. It is also surprisingly found that cholesterol metabolism is highly involved in the NK cell activation by IL-15/2-PEG-PTMC. Following stimulation with IL-15/2-PEG-PTMC or IL-15, NK cells undergo a series of cholesterol metabolism reprogramming, which elevates the cholesterol levels on NK cell membrane. This in turn promotes the formation of lipid rafts and activates immune synapses, effectively contributing to the enhancement of NK cell's antitumor activity. It is believed that it will open a new avenue for improving the efficacy of NK cell immunotherapy by regulating cholesterol metabolism.
Insights
This study developed a novel micelle system for codelivering IL-15 and IL-2 to enhance natural killer (NK) cell immunotherapy. The system improved NK cell activity and delayed tumor growth by reprogramming cholesterol metabolism.
Area of Science:
- Immunology
- Biotechnology
- Cancer Research
Background:
- Natural killer (NK) cells are crucial for cancer immunotherapy but have suboptimal antitumor efficacy.
- Clinical translation of cytokine-based NK cell activation faces challenges like multiple cytokine coactivation, poor pharmacokinetics, and limited mechanistic understanding.
Purpose of the Study:
- To develop a polymeric micelle-based system for co-delivering Interleukin-15 (IL-15) and Interleukin-2 (IL-2) to enhance NK cell activation.
- To investigate the in vivo efficacy and underlying mechanisms of this novel codelivery system for cancer immunotherapy.
Main Methods:
- Development of a polymeric micelle-based IL-15/IL-2 codelivery system (IL-15/2-PEG-PTMC).
- In vivo evaluation of the system's impact on IL-15 and IL-2 half-life, NK cell recruitment, and tumor growth.
- Analysis of NK cell activation pathways, including cholesterol metabolism, lipid raft formation, and immune synapse activation.
Main Results:
- The IL-15/2-PEG-PTMC system significantly increased the half-life of IL-15 and IL-2 and enhanced NK cell recruitment in tumor tissues.
- Codelivery via IL-15/2-PEG-PTMC notably delayed tumor growth compared to free cytokines.
- Cholesterol metabolism reprogramming, leading to elevated cell membrane cholesterol, lipid raft formation, and immune synapse activation, was identified as a key mechanism for enhanced NK cell antitumor activity.
Conclusions:
- The polymeric micelle-based IL-15/IL-2 codelivery system effectively enhances NK cell immunotherapy by improving pharmacokinetics and coactivation.
- Regulation of cholesterol metabolism represents a novel strategy to boost NK cell antitumor activity and improve immunotherapy efficacy.
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