Abstract 811: Development of a NOX-ROS nanoinhibitor for enhancing response to radiotherapy in lung cancer cells while mitigation radiation-induced inflammation and injury in the normal lung tissue

Abstract Objective: One of the unmet clinical challenges is that many tumors remain insensitive to radiotherapy owing to intrinsic resistance or acquired resistance that leads to tumor progression or recurrence. Moreover, radiation-induced acute injury and chronic inflammation in normal tissues limit the radiation dose that can be applied to the tumor, and tolerable doses are often linked to suboptimal tumor control—even accepting side effects that lead to decreased quality of life. Our goal of the study is to develop a nanoformulated radiosensitizer that inhibits NOX-ROS signal pathway to enhance therapeutic response in tumor cells while reducing radiotoxicity in normal tissues. Methods: We developed a biomaterial-based nanoparticle radiosensitizer that acts upon abnormal redox status and altered metabolism in tumor cells to trigger a cascade of changes in signal pathways to enhance response to radiotherapy. This CD44-targeted radiosensitizer consists of a biodegradable and bioactive hyaluronic acid nanoparticle (HANP) encapsulated with a dual NOX1/4 inhibitor, GKT831 (HANP/GKT831). Orthotopic and subcutaneous NSCLC tumor mouse models using a WRJ388 cell line that was isolated from a metastatic lung adenocarcinoma in a lymph node of a KrasG12D/Lkb1null GEMM mouse were established for evaluation of the effect on the inhibition of tumor growth and protection of normal tissue after the treatment with intravenous administrations of HANP/GKT831 at 5 mg/kg (twice per week for five times) combined with radiation (2 Gy/each dose, twice per week for five times). The anti-tumor effect, immune response, and inflammation in the normal lung tissues were investigated using histological and immunofluorescence analyses. Results: Our results showed that HANP/GKT831 had stronger inhibitory effects on ROS generation and cell proliferation than that of GKT831 in mouse NSCLC tumor cells in vitro. Systemic injection of HANP/GKT831 combined with radiation had the strongest inhibition on tumor growth (~79%) compared with the combination of non-nanoformulated GKT831 with radiation treated mouse group (<50%). HANP/GKT831 combined with radiation led to an increased tumor specific CD8+ T cells in tumors and markedly reduced the level of myeloid derived suppressive cells (CD11b+/GR1+) in tumors. Furthermore, the combination of radiation and HANP/GKT831 reduced inflammatory cytokines, such as IFN-γ and TNF-α, and cells (CD11b+ cells) in the irradiated normal lung tissues. Conclusion: HANP/GKT831 is a biomaterial-based nanoparticle radiosensitizer that acts upon abnormal redox status and altered metabolism in tumor cells to trigger a cascade of changes in signal pathways to enhance the response of tumor cells to radiotherapy. It also has the potential to reduce the radiation-induced inflammatory response in normal lung tissues. Citation Format: Lei Zhu, Lumeng Zhang, Tongrui Liu, Wei Ping Qian, Wei Zhou, Lily Yang. Development of a NOX-ROS nanoinhibitor for enhancing response to radiotherapy in lung cancer cells while mitigation radiation-induced inflammation and injury in the normal lung tissue [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 811.