46 | Investigating the impact of the tumor secretome on in vitro human skeletal and cardiac muscle models of cancer-induced cachexia

Ashley Ju-Wei Wang¹, L. Yedigaryan ^1|2, M. Campaner Socias¹, J. Zhang¹, F. Palmieri³, L. Rinvenuto¹, V. Marini¹, R. Squecco³, M. Seelaender⁴, M. Sampaolesi^1|5 | ¹Laboratory of Translational Cardiomyology, Stem Cell Institute Leuven, Department of Development and Regeneration, KU Leuven, Leuven, Belgium; ²IGBMC (Institut de Génétique et de Biologie Moléculaire et Cellulaire), Inserm U1258, CNRS UMR7104, Université de Strasbourg, Illkirch, France; ³Department of Experimental and Clinical Medicine, Section of Physiological Sciences, University of Florence, Florence, Italy; ⁴Cancer Metabolism Research Group, Institute of Biomedical Sciences, University of São Paulo, São Paulo SP, Brazil; ⁵Histology and Medical Embryology Unit, Department of Anatomy, Histology, Forensic Medicine and Orthopaedics, Sapienza University of Rome, Rome, Italy. | Correspondence to A. Ju-Wei Wang and M. Sampaolesi, ashley.wang@kuleuven.be; maurilio.sampaolesi@kuleuven.be.

Cancer cachexia is a complex and poorly diagnosed metabolic syndrome primarily characterized by depletion of skeletal muscle and adipose tissue. Although cachexia impacts multiple organs, including the heart, research has remained focused on skeletal muscle, with no robust in vitro model of cardiac cachexia available. Furthermore, current knowledge regarding cancer cachexia is mainly derived from animal studies, which lack direct translatability to human physiology. Therefore, this project aims to bridge these gaps by integrating an established murine model of cancer cachexia with advanced human in vitro systems and, ultimately, patient-derived tissue explants to investigate the effects of the tumor secretome on skeletal and cardiac muscles. Specifically, we developed fully human in vitro models by indirectly exposing immortalized myoblasts to the secretome of human colon carcinoma cells (HCT116) using transwell-based co-cultures, which led to reduced expression of mature myogenic markers and formation of smaller myotubes. Applying the same approach to human induced pluripotent stem cell (hiPSC)-derived cardiomyocytes, we observed impaired cardiac differentiation and maturation as well as reduced cardiomyocyte contractile function. Experiments with hiPSC-derived cardiac organoids, which offer increased complexity and greater physiological relevance, are ongoing. In parallel, since we have observed more small extracellular vesicles (sEVs) containing stress-related proteins in cachectic cancer patients compared to weight stable patients, we have begun testing the sEV inhibitor Manumycin A in our cell systems. These experiments showed reduced sEV secretion, and we plan to assess whether sEV inhibition can mitigate cachectic phenotypes in our skeletal and cardiac models. By leveraging state-of-the-art human models and sEV-modulating interventions, this research will provide crucial insights into cachexia-induced alterations in skeletal and cardiac muscles.