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Disrupting EDEM3-induced M2-like macrophage trafficking by glucose restriction overcomes resistance to PD-1/PD-L1
Shaoyong Peng1,2, Minshan Wu1,2,3,4,5,6, Qian Yan2,3,4,5,6
1Department of General Surgery (Colorectal Surgery), The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China.
Background:
Immunotherapy is beneficial for some colorectal cancer (CRC) patients, but immunosuppressive networks limit its effectiveness. Cancer-associatedfibroblasts (CAFs) are significant in immune escape and resistance toimmunotherapy, emphasizing the urgent need for new treatment strategies.
Methods:
Flow cytometric, Western blotting, proteomics analysis, analysis of public database data, genetically modified cell line models, T cell coculture, crystal violetstaining, ELISA, metabonomic and clinical tumour samples were conducted to assess the role of EDEM3 in immune escape and itsmolecular mechanisms. We evaluated theeffects of FMD plus 2-DG on antitumour immunity using multipleximmunofluorescence, flow cytometry, cytokine profiling, TUNEL assays, xenografttumours, and in vivo studies.
Results:
We show thatCAFs upregulate PD-L1 glycosylation and contribute to immune evasion byglycosyltransferase EDEM3. Additionally, EDEM3 plays a role in tumour immunityduring tumour progression. However, the EDEM3-mediated upregulation of PD-L1 expression underpins PD-1/PD-L1 blockade resistance in vivo. This finding contradictsthe previous trend that positive PD-L1 expression indicates a strong responseto PD-1/PD-L1 blockade. Mechanistically, high-EDEM3 expression facilitates M2-like This finding contradictsthe previous trend that positive PD-L1 expression indicates a strong responseto PD-1/PD-L1 blockade.Mechanistically, polarizationand chemotactic migration of macrophages, which are enriched in theperipheral region of tumours compared to thecore region, precluding access of CD8+ T cells to tumourfoci. Furthermore, we EDEM3 predominantly activates the recruited M2-like macrophagesvia a glucose metabolism-dependent mechanism. Manipulationof glucose utilization by a fasting-mimicking diet(FMD) plus 2-DG treatmentsynergistically with PD-1 antibody elicits potent antitumour activity byeffectively decreasing tumour glycosylated PD-L1 expression, augmenting the CD8+effector T cell infiltration and activation while concurrently reducing the infiltration.TheCAFs-EDEM3-M2-like macrophage axis plays a critical role in promotingimmunotherapy resistance. infiltration.TheCAFs-EDEM3-M2-like macrophage axis plays a critical role in promotingimmunotherapy resistance.
Conclusions:
Our study suggests that blocking EDEM3-induced M2-like macro phage trafficking by FMD plus 2-DG is a promising and effective strategy to overcomeresistance to checkpoint blockade therapy offeringhope for improved treatment outcomes.
Key Points:
Cancer-associated fibroblasts (CAFs) can enhance PD-L1 glycosylation through the glycosyltransferase EDEM3, contributing to immune evasion during tumour progression. EDEM3 predominantly activates the recruit M2-like macrophages via a glucose metabolism-dependent mechanism. Blocking glucose utilization antagonizes recruiting and polarizing M2-like macrophages synergistically with PD-1 antibody to improve anticancer immunity.
Insights
Blocking cancer-associated fibroblasts (CAFs) and EDEM3 with a fasting-mimicking diet (FMD) plus 2-DG overcomes immunotherapy resistance in colorectal cancer by targeting M2-like macrophages and enhancing T cell response.
Area of Science:
- Oncology
- Immunology
- Cancer Biology
Background:
- Immunotherapy shows promise for colorectal cancer (CRC) but faces limitations due to immunosuppressive networks.
- Cancer-associated fibroblasts (CAFs) significantly contribute to immune evasion and immunotherapy resistance in CRC.
- Novel therapeutic strategies are urgently needed to overcome these resistance mechanisms.
Purpose of the Study:
- To investigate the role of EDEM3 in immune evasion mediated by CAFs in colorectal cancer.
- To elucidate the molecular mechanisms by which EDEM3 contributes to immunotherapy resistance.
- To evaluate the efficacy of combining a fasting-mimicking diet (FMD) with 2-deoxy-D-glucose (2-DG) to overcome resistance to PD-1/PD-L1 blockade therapy.
Main Methods:
- Utilized flow cytometry, Western blotting, proteomics, and analysis of public and clinical tumor data.
- Employed genetically modified cell line models, T cell co-culture assays, and ELISA.
- Assessed anti-tumor immunity using multiplex immunofluorescence, cytokine profiling, TUNEL assays, and in vivo xenograft studies.
Main Results:
- CAFs upregulate PD-L1 glycosylation via glycosyltransferase EDEM3, promoting immune evasion and resistance to PD-1/PD-L1 blockade.
- High EDEM3 expression promotes M2-like macrophage polarization and migration, hindering CD8+ T cell infiltration.
- EDEM3 activates M2-like macrophages through a glucose metabolism-dependent pathway.
- Combined FMD and 2-DG treatment synergizes with PD-1 antibody to reduce PD-L1 glycosylation, enhance CD8+ T cell activity, and reduce M2-like macrophage infiltration.
Conclusions:
- The CAFs-EDEM3-M2-like macrophage axis is critical for promoting immunotherapy resistance in colorectal cancer.
- Blocking EDEM3-induced M2-like macrophage trafficking via FMD plus 2-DG is a promising strategy to overcome resistance to checkpoint blockade therapy.
- This approach offers hope for improved treatment outcomes in patients resistant to current immunotherapies.
