Human pancreatic tumour organoid‐derived factors enhance myogenic differentiation

Background Most patients with pancreatic cancer develop cachexia, which is characterized by progressive muscle loss. The mechanisms underlying muscle loss in cancer cachexia remain elusive. Pancreatic tumour organoids are 3D cell culture models that retain key characteristics of the parent tumour. We aimed to investigate the effect of pancreatic tumour organoid‐derived factors on processes that determine skeletal muscle mass, including the regulation of muscle protein turnover and myogenesis. Methods Conditioned medium (CM) was collected from human pancreatic cancer cell lines (PK‐45H, PANC‐1, PK‐1, and KLM‐1), pancreatic tumour organoid cultures from a severely cachectic (PANCO‐9a) and a non‐cachectic patient (PANCO‐12a), and a normal pancreas organoid culture. Differentiating C2C12 myoblasts and mature C2C12 myotubes were exposed to CM for 24 h or maintained in control medium. In myotubes, NF‐kB activation was monitored using a NF‐κB luciferase reporter construct, and mRNA expression of E3‐ubiquitin ligases and REDD1 was analysed by RT‐qPCR. C2C12 myoblast proliferation and differentiation were monitored by live cell imaging and myogenic markers and myosin heavy chain (MyHC) isoforms were assessed by RT‐qPCR. Results Whereas CM from PK‐1 and KLM‐1 cells significantly induced NF‐κB activation in C2C12 myotubes (PK‐1: 3.1‐fold, P