Abstract LB164: Development of a novel lung cancer orthotopic transplantation model for preclinical evaluation of anticancer agents

Abstract Heterotopic transplantation models, in which tumors are transplanted subcutaneously (SC model), are widely employed in cancer research because of their technical simplicity and ease of measuring tumor size. However, the SC model cannot replicate the primary tumor site, limiting its capacity to reflect the tumor microenvironment and natural progression accurately. To address this limitation, we developed a novel orthotopic transplantation (ORT) lung cancer model using bronchoscopy. This study aimed to compare the pathological features and evaluate the efficacy of the cytotoxic anticancer agents (carboplatin [CBDCA] and paclitaxel [PTX]) in ORT and SC models.In the ORT model, 3% lauryl-10 solution was administered to promote tumor engraftment in the left lung lobule via bronchoscopy three days before cancer cell transplantation. Two luciferase-expressing lung adenocarcinoma cell lines (A549-Luc and RERF-LC-KJ/CMV-Luc) were used in this study. The cells (1×105 cells in 20 μL of medium with 10% Matrigel) were transplanted into the left lung lobule of NOG mice on day 0. In the SC model, the same cell lines (1×105 cells in 100 μL of medium with 50% Matrigel) were injected subcutaneously. Tumor growth was monitored using luciferin luminescence in the ORT model and caliper-based measurements in the SC model.Pathologically, the SC model exhibited stable tumor growth characterized by central necrosis. In contrast, the ORT model exhibited scattered tumor nodules in the alveolar spaces without significant necrosis, closely mimicking the tumor microenvironment of lung cancer. The efficacy of the anticancer agents was assessed by administering CBDCA (50 mg/kg intraperitoneally, three times at five-day intervals) and PTX (15 mg/kg intraperitoneally, five times at three-day intervals) two weeks after tumor transplantation.In the ORT model with A549-Luc cells, PTX reduced luciferin luminescence, whereas CBDCA showed no notable effect, which is consistent with the results of the SC model. However, in the RERF-LC-KJ/CMV-Luc cell line, luciferin luminescence decreased following CBDCA treatment in both ORT and SC models. These findings suggest that the ORT model effectively reflects the differential responses of lung cancer cell lines to anticancer agents and provides a more physiologically relevant platform for drug evaluation.In conclusion, our bronchoscopy-based orthotopic lung cancer model offers a promising preclinical research tool for assessing tumor behavior and therapeutic efficacy in a more biologically relevant context than the SC model. Further studies using this model may advance our understanding of lung cancer pathophysiology and facilitate therapeutic development. Citation Format: Chiyoko Nishime, Eiko Nishinaka, Hitomi Satou, Toshio Imai, Misa Mochizuki, Kenji Kawai, Taichi Yamamoto, Masami Suzuki. Development of a novel lung cancer orthotopic transplantation model for preclinical evaluation of anticancer agents [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_2):Abstract nr LB164.