면역항암제 효능 평가 및 저항성 발현 기전 탐구를 위한 난소암 동소이종이식 인간화 마우스 모델 개발 및 특성화

Abstract

Background: Although immunotherapy has not yet been as successful in ovarian cancer (OC), it holds promise as a therapeutic approach. Preclinical models of OC are necessary to evaluate the efficacy of immuno-oncology (IO) drugs targeting human immune components but have been currently underexploited. Developing mouse models with a humanized (Hu) immune system could enhance our understanding of the human immune response to IO drugs, which have so far shown limited effectiveness in OC. This study aimed to establish a Hu mouse model of OC that mimics the OC tumor microenvironment (TME) with a human immune system. Methods: OC xenograft models were established in CD34+ Hu-mice by intraperitoneal injection with luciferase-expressing SKOV-3 Luc and OVCAR-3 Luc OC cells. Tumor growth was monitored using bioluminescence imaging (BLI), and the efficacy of PD-1 blockade with pembrolizumab was assessed in the SKOV-3 Luc Hu-mouse model. The immune profiles of the tumors were examined using colorimetric immunostaining and flow cytometry. RNA-seq data were also analyzed to explore the gene expression signature of pembrolizumab non- responsive tumors. Results: Tumor formation and growth were confirmed by increased BLI in both OC orthotopic xenograft Hu-mice models. Human lymphocyte and myeloid cell subsets were detected in the tumors, draining lymph nodes, blood, and spleens of these models. The SKOV-3 Luc tumor- bearing Hu-mice did not respond to pembrolizumab monotherapy. These tumors in this model exhibited a high prevalence of tumor-infiltrating macrophages. The tumors within intraperitoneal cavity of Hu-mice treated pembrolizumab showed lower levels of CD8+ T cells, memory B cells, and plasma cells, and higher levels of naïve M0 macrophages and activated mast cells compared to tumors in the PBS control group. Moreover, increased expression of Histone deacetylases (HDAC) class I target genes, genes associated with epithelial- mesenchymal transition (EMT), and fibroblasts were identified in tumors of pembrolizumab- treated Hu-mice. Conclusion: This study confirmed the successful growth of SKOV-3 Luc and OVCAR-3 Luc OC cells in the peritoneal cavity of Hu-mice. The two OC xenograft Hu-mouse models established in this study serves as a valuable resources for investigating the efficacy of IO drugs.