Neoadjuvant Chemotherapy by Liposomal Doxorubicin Boosts Immune Protection of Tumor Membrane Antigens-Based Nanovaccine

Using Liposomal Doxorubicin Neoadjuvant Chemotherapy to Enhance Immune Protection of Tumor Membrane Antigen-Based Nanovaccine

Background and Significance

Surgical resection remains the primary treatment for solid tumors, but postoperative tumor recurrence and metastasis continue to be major challenges. A promising emerging strategy in personalized immunotherapy is tumor membrane antigen-based vaccines (TMVs). These vaccines utilize patients’ own tumor cells as the source of antigens, capable of activating immune responses to reduce the risk of recurrence and metastasis. However, the clinical efficacy of autologous tumor cells remains limited, constrained by the inherently weak immunogenicity of tumor cells.

In clinical practice, patients are often subject to various therapeutic modalities, such as systemic preoperative chemotherapy (neoadjuvant chemotherapy), before receiving personalized tumor antigen-based vaccines. Studies have shown that chemotherapy can alter the tumor immune microenvironment and release tumor-associated antigens and signals through immunogenic cell death (ICD). However, the immunosuppressive side effects of chemotherapy may also weaken vaccine efficacy. To date, no study has directly explored the impact of neoadjuvant chemotherapy on the efficacy of tumor membrane antigen-based vaccines.

In response to this knowledge gap, Professor Yang Chen and colleagues conducted a systematic study to investigate the effect of preoperative chemotherapy on the efficacy of autologous tumor membrane antigen-based vaccines and assess the potential of a nanoparticle-bound liposomal formulation of doxorubicin (NP-Dox) in enhancing the immune protective effect of these vaccines.

Source of the Study

This research paper was conducted by Yang Chen, Hao Qin, Nan Li, and colleagues from institutions including the National Center for Nanoscience and Technology, the University of the Chinese Academy of Sciences, and Capital Medical University. The paper was published on January 21, 2025, in Cell Reports Medicine, under the title “Neoadjuvant Chemotherapy by Liposomal Doxorubicin Boosts Immune Protection of Tumor Membrane Antigen-Based Nanovaccine.”

Research Process in Detail

Experimental Workflow and Methods

  1. Tumor Membrane Extraction and Nanovaccine Preparation
    The researchers collected tumors from three groups of mice following surgery: untreated (TM group), treated with free doxorubicin (DTM group), and treated with liposomal doxorubicin (NTM group). Tumor membranes (TM, DTM, NTM) were then extracted through enzymatic and ultrasonic processing. These membranes were co-extruded with PLGA-R848 nanoparticles, which encapsulate a potent toll-like receptor 78 agonist (Resiquimod). This procedure yielded three tumor membrane nanovaccines: TM-NPs, DTM-NPs, and NTM-NPs.

  2. Proteomic Analysis of Tumor Membranes
    Proteomic analysis was conducted to compare the protein composition of the three tumor membranes (TM, DTM, NTM) and their involvement in immune-related pathways. Results revealed that the tumor membranes from the NTM group (NTM) exhibited significant upregulation of immune-effector process-related proteins such as MHC class I molecules and their antigen-presenting abilities. These findings demonstrate that NP-Dox chemotherapy not only modifies the immune properties of tumor membranes but also enhances their immunogenicity.

  3. In Vitro Immune Effects
    In vitro experiments showed that all three nanovaccines were internalized by bone marrow-derived dendritic cells (BMDCs) and induced their maturation. The NTM-NPs group significantly increased the expression of co-stimulatory molecules (CD80 and CD86) in BMDCs. ELISA assays revealed elevated pro-inflammatory cytokine production (IL-1β, IL-6, TNF-α) in this group. Furthermore, TMVs directly activated isolated mouse CD8+ T cells, with the NTM-NPs group achieving the highest T cell activation efficiency.

  4. In Vivo Immunity Studies and Tumor Model Experiments
    Using 4T1 breast cancer and B16-F10 melanoma mouse models, the researchers conducted in vivo experiments to observe the inhibitory effects of postoperative vaccination on tumor recurrence and metastasis. Results showed that the NTM-NPs group not only significantly increased the number of infiltrating effector CD8+ T cells in the tumor site but also reduced the proportion of regulatory T cells (Tregs). This group suppressed postoperative recurrence and metastasis and notably prolonged the survival rate of mice.

  5. Safety Assessment and Immune Microenvironment Analysis
    Mice experienced slight weight loss at the beginning of chemotherapy but gradually returned to normal. Histological analysis (H&E staining) revealed no significant damage to major organs. In addition, the tumor microenvironment in the NTM-NPs group showed a marked increase in pro-inflammatory M1 macrophages and a decrease in tumor-promoting M2 macrophages, further confirming NP-Dox’s effect on improving the immune microenvironment.

Supporting Data

  • Proteomic analysis identified 359 unique immune-related proteins in the NTM group, with upregulated MHC class I antigen-presentation pathways directly confirming NP-Dox chemotherapy’s impact on enhancing tumor immunogenicity.
  • In vitro, the NTM-NPs group induced 312 pg/mL of IL-6 production from BMDCs, nearly three times higher than the TM group.
  • In the 4T1 model, none of the mice in the NTM-NPs group exhibited tumor recurrence, compared to 62.5% and 87.5% in the DTM-NPs and TM-NPs groups, respectively.

Conclusions and Significance

The study demonstrated that preoperative use of NP-Dox can enhance the efficacy of tumor membrane antigen-based vaccines through the following mechanisms: 1. Activating the immune microenvironment at the tumor site. 2. Significantly upregulating tumor membrane antigens and immune-related molecule expression. 3. Improving vaccine internalization and dendritic cell maturation efficiency. 4. Effectively activating anti-tumor effector T cells.

These findings confirm that neoadjuvant chemotherapy can induce immunogenic changes in tumor cells, which not only enhance the immunoprotective effect of postoperative vaccines but also provide a new strategy for the clinical application of personalized tumor vaccines.

Highlights of the Research

  • Innovative Approach: The study employed liposomal formulation of doxorubicin to enhance drug targeting and reduce side effects, achieving significant modifications in tumor membrane immune properties.
  • Key Discoveries: For the first time, it was found that preoperative chemotherapy significantly improves TMVs’ immune efficacy, with optimized NTM-NPs vaccines demonstrating superior performance in both in vitro and in vivo experiments.
  • Clinical Potential: The study emphasized the critical role of chemotherapy drug selection in vaccine preparation, offering theoretical guidance for personalized cancer treatment.

With rigorous mechanistic exploration and comprehensive data validation, this study lays a vital foundation for future chemo-vaccine combination strategies in cancer immunotherapy, demonstrating impressive scientific and clinical value.