Abstract 485: Cancer killing effect of ultrasound-responsive mechanophore nanoparticles

Abstract Radiotherapy, a mainstay in cancer treatment, often inadvertently damages healthy tissues while targeting malignancies with free radicals. As an alternative, Photodynamic Therapy (PDT) employs non-ionizing photons to generate reactive oxygen species (ROS) in tumors, offering precise targeting with minimal long-term effects. However, its efficacy is constrained to superficial tumors due to the limited penetration of light. Sonodynamic Therapy (SDT), an evolution of PDT, uses ultrasound to enhance tissue penetration while maintaining its non-invasive nature. Initial SDT studies suggest that ultrasound can activate PDT's photosensitizers to produce ROS, offering a potential pathway for tumor eradication. Nevertheless, the principal mechanisms of ROS generation in SDT, namely pyrolysis and sonoluminescence, raise concerns about potential tissue injury. In our research, we introduce an innovative approach employing mechanophores into nanoparticles. Mechanophores, molecular units within polymers sensitive to mechanical stress, undergo transformations under such conditions, including the release of small molecules or free radicals. We have developed injectable nano-sized mechanophore nanoparticles, designed to respond to high-frequency ultrasound (>100 kHz) more efficiently and with reduced energy requirements. This study focuses on nano-engineering the echogenicity of these mechanophore nanoparticles to enhance ROS generation. When agitated with focused ultrasound (FUS), these nanoparticles successfully induced ROS, leading to significant cell death, a result not observed with FUS alone in the absence of nanoparticles. In vivo experiments using mouse orthotopic cancer models demonstrated these nanoparticles' ability to inhibit tumor growth effectively. Under biocompatible ultrasound conditions, the nanoparticles cause effective cancer cell eradication with minimal impact on surrounding healthy tissues. Our findings not only introduce a novel approach to cancer treatment but also pave the way for broader applications of mechanophore nanoparticles in biomedicine. This study underscores the potential of ultrasound-activatable mechanophore nanoparticles as a versatile, effective, and safe option for cancer therapy. Citation Format: Jian Wang, Shensheng Zhao, Junxi Yi, Yunyan Sun, Megha Agrawal, King Li, Jeffrey S. Moore, Michael Oelze, Yun-Sheng Chen. Cancer killing effect of ultrasound-responsive mechanophore nanoparticles [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 485.