Loss of Two-pore channel 2 enhances CD8+ T cell cytotoxicity and directly impairs tumour growth via MAPK axis in HCC

Lina Ouologuem¹Anna Kübler²Sarah Ouologuem³Amar Hadzic^4,5,6Jan B. Stöckl⁷Anna Chiara Siciliano⁸Stefania Forciniti⁸Salvatore Nigro⁸Helena Iuele⁸Valentina Onesto⁸Anny Nguyen⁹Dana Matzek¹⁰Carla Abrahamian^11,12,13Prof. Dr. Dr. Christian Grimm^11,14,15Bastian Popper¹⁰Giuseppe Gigli⁸Loretta Laureana del Mercato⁸Olivia M. Merkel^16,9Thomas Frohlich⁷Sebastian Theurich^4,5,6Karin Bartel^16,9*

• ¹Ludwig-Maximilians-Universitat Munchen Department Pharmazie, Munich, Germany
• ²Ludwig Maximilian University of Munich, Munich, Germany
• ³Ludwig-Maximilians-Universitat Munchen Institut fur Informatik, Munich, Germany
• ⁴Gene Center, Cancer- and Immunometabolism Research Group, Ludwig-Maximilians-Universität München, Munich, Germany
• ⁵Department of Medicine III, LMU University Hospital, Ludwig-Maximilians-Universität München, Munich, Germany
• ⁶Deutsches Krebsforschungszentrum, Heidelberg, Germany
• ⁷Gene Center, Laboratory for Functional Genome Analysis, Ludwig-Maximilians-Universität München, Munich, Germany
• ⁸Istituto di Nanotecnologia Consiglio Nazionale delle Ricerche, Lecce, Italy
• ⁹Department of Pharmacy, Pharmaceutical Technology, Ludwig-Maximilians-Universität München, Munich, Germany
• ¹⁰Ludwig-Maximilians-Universitat Munchen Biomedizinisches Centrum Munchen, Munich, Germany
• ¹¹Ludwig-Maximilians-Universitat Munchen Walther-Straub-Institut fur Pharmakologie und Toxikologie, Munich, Germany
• ¹²Department of Cardiology, German Heart Centre, TUM University Hospital, TUM School of Medicine and Health, Technical University of Munich, Munich, Germany
• ¹³German Centre for Cardiovascular Research (DZHK e.V.), partner site Munich Heart Alliance, Munich, Germany
• ¹⁴University of Oxford Nuffield Department of Medicine, Oxford, United Kingdom
• ¹⁵Fraunhofer-Institut fur Translationale Medizin und Pharmakologie ITMP, Frankfurt, Germany
• ¹⁶Cluster for Nucleic Acid Therapeutics Munich (CNAT-M), Munich, Germany

Hepatocellular carcinoma (HCC) remains a major global health challenge with limited therapeutic options and high mortality rates. Despite advances in systemic and immunotherapies, many patients develop resistance or fail to respond, underscoring the need for novel therapeutic targets. Lysosomal ion channels have recently emerged as key regulators of cancer progression, yet their role in tumour–immune interactions remain poorly defined. Here, we identify the endolysosomal two-pore channel 2 (TPC2) as a critical modulator of immune evasion in HCC. Loss of TPC2 function enhances CD8⁺ T cell-mediated cytotoxicity by upregulating MHC-I and downregulating PD-L1 expression both in vitro and in vivo. Moreover, combination treatment of TPC2 inhibitor SG094 with immune checkpoint inhibitor (ICI) Nivolumab enhances CD8+ T cell cytotoxicity in vitro compared to single ICI treatments. Mechanistically, multi-omics profiling reveals that TPC2 knockout (KO) disrupts amino acid metabolism, glycolysis, and protein translation, resulting in reduced ERK1/2 expression and impaired MAPK signalling. This disruption contributes to the observed diminished tumour proliferation and metabolic activity, alongside enhanced MHC-I surface expression. Our findings establish TPC2 as a dual regulator of tumour-intrinsic signalling and immune evasion, highlighting its potential as a therapeutic target to improve immunotherapy responses in HCC.