Abstract 6573: Real-time precision analysis of exosome treatment in cancer immunodynamics using intravital microscopy

Abstract Exosomes play a crucial role in cancer therapy, actively engaging in stimulating the tumor microenvironment and recruiting immune cells, as demonstrated by numerous studies. In exosome-based cancer therapy, precision diagnosis of immune mechanisms utilizes technologies such as X-ray, PET, CT, MRI, and bioluminescence analysis. However, further research is needed to fully understand the impact of exosomes on cancer development and suppression. Particularly, the potential functions of exosomes in cancer immunotherapy and drug delivery have garnered significant attention. Therefore, novel precision analysis methods are essential to further advance these well-established functions in cancer therapy. This is because exosomes play a vital role in critical steps of cancer cell therapy, such as efficient trafficking in cancer metabolism, navigation through the tumor microenvironment, entry into the vasculature, and resumption of inhibitory processes.To address these needs, we conducted a study utilizing exosomes in a brain cancer cell xenograft mouse model and analyzed cancer metabolism treated with exosomes using intravital microscopy (IVM), comparing it with a bioluminescence system. First, exosome fluorescence signals in the xenograft mouse model were screened using the IVIS system. Subsequently, intravital microscopy was performed on the same mouse model to track the trafficking of the exosome fluorescence signals.As a result, IVM demonstrated more detailed and precise expression of exosome fluorescence signals in the xenograft mouse model compared to the IVIS system, which also revealed macrophage activity in the same region. While the IVIS system displayed fluorescence signals as contour-like patterns, IVM provided significantly more detailed and meaningful signals, especially in terms of efficacy, based on the morphology of blood vessels observed in the in vivo mouse model. Furthermore, IVM revealed how interactions between exosomes and cancer cells manifest as phenotypic signals. This indicates that exosome activation is expressed not only at the site of cancer cell accumulation in the brain but also directly at the cancer cell site. Such detailed observations are achievable only with the IVM system, as the IVIS system is insufficient to monitor these intricacies in the xenograft model.These findings suggest that IVM systems are likely to align with the trends in new drug development and regulatory guidelines from institutions such as the FDA, EMA, and TGA. Additionally, the efficiency and functionality of exosomes are best expressed and validated through intravital microscopy, demonstrating its potential as an essential precision analysis method. Citation Format: Hyunseok Kim, Hyungjin Kwon, Jenny Junghyon Ohm, Junyoung Park, Sungwoon Yoon, Kubra Akyildiz, Hsuan-Ju Chen. Real-time precision analysis of exosome treatment in cancer immunodynamics using intravital microscopy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 6573.