Abstract 3666: A human skeletal muscle stem/myotube model reveals multiple signaling targets of cancer secretome in skeletal muscle

Abstract

Abstract Skeletal muscle dysfunction due to the effects of cancer secretome is observed in multiple cancer types and extreme dysfunction is manifested as cachexia. Major preclinical studies on cancer-associated muscle defects utilized mouse models or mouse C2C12 mouse myoblast cell line for in vitro studies. Because of species specificity of certain cytokines/chemokines in the secretome, a human model system is required to fully comprehend the effects of cancer secretome on skeletal muscle. Here, we report a simple method to establish skeletal muscle stem cell line (hMuSC), which can be differentiated into myotubes. Using single nuclei ATAC-seq (snATAC-seq) and RNA-seq (snRNA-seq), we document chromatin accessibility and transcriptomic changes associated with hMuSCs to myotube transition. Cancer cell line derived factors accelerated stem to myotube differentiation with accompanying changes including an increase in PAX7+/MyoD+ myogenic progenitor cells. Among the pathways activated by cancer-derived factors include inflammatory pathway involving CXCL8 (also called IL-8), glucocorticoid receptor (GR) pathway, and wound healing pathway. Furthermore, cancer-derived factors significantly altered splicing machinery in hMuSCs. Additionally, AKT and p53 pathways that function in metabolic/survival pathways of the skeletal muscle were adversely affected when hMuSCs were exposed to cancer cell-derived factors. Cancer-derived factors increased the expression levels of previously known cachexia-associated genes such as MT-2, ZIP14, and PDK4. Thus, the model system not only recapitulates results of previous mouse studies but also provides much needed human model system that can easily be adapted for large scale studies to explore the epigenomic changes during hMuSC differentiation and to screen for drugs that restore skeletal muscle function in various diseases. Citation Format: Ruizhong Wang, Brijesh Kumar, Poornima Bhat-Nakshatri, Aditi Sanjay Khatpe, Michael P. Murphy, Kristen E. Wanczyk, Emma H. Doud, Amber L. Mosley, Yunlong Liu, Duojiao Chen, Ed Simpson, Hongyu Gao, Harikrishna Nakshatri. A human skeletal muscle stem/myotube model reveals multiple signaling targets of cancer secretome in skeletal muscle. [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 3666.