Combining glutathione and electroporation as novel head and neck cancer therapy

• Applicant: Professor Dr. Sander Bekeschus
• Subject Area: Otolaryngology, Phoniatrics and Audiology ; Dermatology ; Hematology, Oncology
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 569251017

Electrochemotherapy (ECT) is based on local tumor electroporation using pulsed electric fields combined with systemic or intratumoral drug injection, leading to locally 50-fold amplified drug uptake and cytotoxicity. This way, the systemic toxicity of anticancer drugs such as bleomycin and cisplatin is drastically decreased. The therapy is frequently used in topical primary or metastatic tumors, such as ulcerating breast cancers, malignant melanomas, and squamous cell carcinoma of the skin and head and neck (HNSCC). However, chemotherapeutics used in ECT have remained unchanged since the 1990s, albeit clinical response rates have room for improvement. We identified glutathione (GSH), the most common biological antioxidant and human dietary supplement, to enable electroporation-induced cancer cell death at unexpectedly high rates in vitro. Counter-intuitively, our data suggest this killing to occur in a ROS-dependent fashion. This proposal outlines a research strategy to elucidate the findings' mechanisms and translational relevance. This includes testing across seven malignant and one non-malignant cell lines, cell death kinetics and mechanisms, the role of ROS auto-amplification by NADPH oxidases, and the immunogenic or immunosuppressive profiles of GSH-electroporated cells. Apart from testing in 2D cultures and 3D tumor spheroids, vascularized and matrix-generating 3D tumors will be tested in the TUM-CAM model in ovo. In addition, a syngeneic mouse model using stably luciferase-expressing murine SCC7 cells will allow in vivo bioluminescence imaging to follow tumor growth non-invasively. The model also allows the dissection of the immune system's role in the anticipated GSH-electroporation-mediated tumor reduction by deciphering the intratumoral leukocyte infiltration and cellular activation status in lymph nodes. This model was recently successfully established in our laboratory to investigate anti-PD1 checkpoint antibody therapy. Pulsed electric field applications have been shown to induce the release of tumor antigens at the treatment site, promoting an abscopal antitumor immune response. Using GSH as a putative 'endogenous drug' injected intratumorally would be a virtually side-effect-free approach with game-changing implications for oncological electroporation therapies beyond HNSCC applications. Specifically, the objectives are: identifying the boundary conditions under which synergistic conditions occur, elucidating the mode of action of combined GSH-electroporation, investigating the tumor debulking capacity and benefit of GSH-electroporation, and assessing the immunological dimension of GSH-electroporation. Benefiting from a strong complementarity and operating in leading international oncology research centers, our consortium may be able to deliver new GSH-PEF basic mechanisms of action and low side-effect protocols that could rapidly be transferred to clinics.

• DFG Programme: Research Grants
• International Connection: France
• Cooperation Partner: Professorin Catherine Brenner, Ph.D.