Abstract 2656: Muscle wasting in head and neck carcinomas: Investigations on the underlying transcriptional reprogrammation

Abstract

Abstract Introduction: Cancer cachexia is a multifactorial syndrome associated with a skeletal muscle atrophy that affects at least 55% of patients bearing Head and Neck Squamous Cell Carcinomas (HNSCCs). To our knowledge, molecular mechanisms of muscle alterations have never been investigated on clinical muscle specimens from HNSCC patients. The aim of this study was to perform transcriptome profiling by bulk RNAseq on muscle fragments from HNSCC patients with and without cachexia and from nude mice bearing human HNSCC xenografts. Methods: Our study was made in three parts: 1) In Vitro investigations on human myoblasts co-cultivated with HNSCC cells. 2) In Situ investigations on muscles collected from nude mice xenografted with HNSSCs cells (FADU). 3) Exploration of clinical muscle samples collected from HNSCC patients. RNA sequencing was used to assess gene expression changes and gene function enrichment related to cachexia, in myoblasts co-cultivated with malignant cells as well as skeletal muscle samples collected from mice xenografted with HNSCC cells (FADU) or HNSCC patients. Results: In vitro experimentations showed significant impact of malignant cells on myoblast proliferation and differentiation. In nude mice, FADU xenografts resulted in distant loss of muscle mass at various anatomic locations. RNA sequencing of muscle samples from cachectic patients showed significant differences in gene expression compared with control muscles samples from tumor-free donors. Commonly modified pathways included immune and inflammatory response, mitochondrial metabolism and striated muscle differentiation. The most remarkable finding was the up-regulation of the BIRC3 transcript which encodes the anti-apoptotic protein c-IAP2. This alteration was observed both in human cachectic muscles and murine muscle fragments from tumor-bearing mice. Conclusions: Although the mechanism of BIRC3 up-regulation in cachectic muscle cells is not well understood, this finding is likely to be important for patient management in a context of promising therapeutic results obtained using Smac mimetics. Because these compounds are inhibitors of the c-IAP protein family, it will be important in the future to monitor their positive or negative effects on muscle alterations in cachectic HNSCC patients. Citation Format: Héla Hachicha, Iryna Pirozhkova, Aurore Gelin, François Bidault, Valérie Rouffiac, Thibault Dayris, Thierry Ragot, Ingrid Breuskin, Caroline Even, Philippe Gorphe, Pierre Busson. Muscle wasting in head and neck carcinomas: Investigations on the underlying transcriptional reprogrammation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2656.