Establishment of Patient-Derived Gastric Cancer Organoids and Peripheral Blood Mononuclear Cells Co-culture Model for Personalized Drug Screening

Selecting effective chemotherapy after immunotherapy remains a major clinical challenge in advanced gastric cancer because patient responses are highly heterogeneous. A major obstacle is the lack of personalized preclinical models that faithfully recapitulate the immune-activated tumor microenvironment (TME) following immunotherapy and enable evaluation of subsequent chemotherapy responses while preserving immune–tumor interactions. Here, we developed an immune-activated co-culture model comprising patient-derived gastric cancer organoids and autologous peripheral blood mononuclear cells (PBMCs). Immune activation was achieved using anti-PD-1-loaded gold nanocages (aPD-1@Au NCs), which integrate near-infrared-triggered photothermal tumor ablation with sustained anti-PD-1-mediated immune modulation. The resulting model recapitulates key features of the post-immunotherapy TME, including enhanced immune-cell infiltration, increased tumor-cell apoptosis, and CD8+ T-cell activation. We then applied this model to evaluate five clinically relevant chemotherapeutic agents, including oxaliplatin, irinotecan, fluorouracil, doxorubicin, and docetaxel, for personalized chemotherapy screening after immunotherapy. Compared with monoculture organoids or non-activated co-cultures, the immune-activated model revealed drug-specific differences in tumor-killing efficacy, immune-mediated chemosensitization, and PBMC toxicity. Among the tested agents, oxaliplatin showed the strongest immune-mediated chemosensitization, whereas docetaxel achieved favorable tumor cell killing with relatively low immunotoxicity. These findings demonstrate that chemotherapy responses after immune activation are highly drug-specific, underscoring the importance of personalized chemotherapy selection following immunotherapy. As a proof-of-concept study, this work establishes an immune-activated patient-derived gastric cancer organoid–PBMC co-culture model that partially recapitulates the post-immunotherapy TME. This model provides a promising framework for developing personalized chemotherapy screening strategies after immunotherapy.

Leping Yan is currently an Associate Professor and Principal Investigator (PI) at the Guangdong Provincial Key Laboratory of Digestive Cancer Research, the Seventh Affiliated Hospital, Sun Yat-sen University. His research centres on the development of advanced organoid-on-chip models to recapitulate the disease microenvironment. He has authored more than 30 peer-reviewed publications, which have attracted over 2300 citations in Google Scholar. Dr. Yan is the inventor of four granted patents, including two overseas and two domestic ones. He serves as an Editorial Board Member for the journal In Vitro Models. In addition, he has secured competitive research grants with a total budget exceeding 4 million CNY. As a principal investigator, he has led multiple projects including two National Key R&D Program projects and a General Program funded by the National Natural Science Foundation of China (NSFC). He also acts as Co-PI for the Horizon EU Staff Exchange project-EngVIPO, an international consortium with collaborators from six countries.