The Effect of Mechanical Stretch on Myotube Growth Suppression by Colon-26 Tumor-Derived Factors.

Jessica L Halle,Brittany R Counts-Franch,Rose M Prince,James A Carson

doi:10.3389/fcell.2021.690452

Jessica L Halle, Brittany R Counts-Franch + Show 2 more

Open Access

https://doi.org/10.3389/fcell.2021.690452

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Abstract

Preclinical models and in vitro experiments have provided valuable insight into the regulation of cancer-induced muscle wasting. Colon-26 (C26) tumor cells induce cachexia in mice, and conditioned media (CM) from these cells promotes myotube atrophy and catabolic signaling. While mechanical stimuli can prevent some effects of tumor-derived factors on myotubes, the impact of mechanical signaling on tumor-derived factor regulation of myosin heavy chain (MyHC) expression is not well understood. Therefore, we examined the effects of stretch-induced mechanical signaling on C2C12 myotube growth and MyHC expression after C26 CM exposure. C26 CM was administered to myotubes on day 5 of differentiation for 48 h. During the last 4 or 24 h of C26 CM exposure, 5% static uniaxial stretch was administered. C26 CM suppressed myotube growth and MyHC protein and mRNA expression. Stretch for 24 h increased myotube size and prevented the C26 CM suppression of MyHC-Fast protein expression. Stretch did not change suppressed MyHC mRNA expression. Stretch for 24 h reduced Atrogin-1/MAFbx, MuRF-1, and LC3B II/I ratio and increased integrin β1D protein expression and the myogenin-to-MyoD protein ratio. Stretch in the last 4 h of CM increased ERK1/2 phosphorylation but did not alter the CM induction of STAT3 or p38 phosphorylation. These results provide evidence that in myotubes pre-incubated with CM, the induction of mechanical signaling can still provide a growth stimulus and preserve MyHC-Fast protein expression independent of changes in mRNA expression.

Highlights

Cancer-induced skeletal muscle wasting, or cancer cachexia, is multifactorial and involves a complex interplay between host- and tumor-derived factors resulting in disrupted skeletal muscle function and metabolism (Jackman et al, 2017; Argiles et al, 2019)
Along with decreased myotube size, C26 + growth media (GM)-treated myotubes had significantly lower protein expression of both myosin heavy chain (MyHC)-Fast (p < 0.001, −50%) and MyHCSlow (p = 0.007, −60%) isoforms compared with the GM and EL4 + GM conditions (Figure 1D)
These results demonstrate that C26 tumor-derived factors can suppress myotube growth and MyHC protein expression and that these effects are specific to cachectic tumor-derived factors

Summary

Introduction

Cancer-induced skeletal muscle wasting, or cancer cachexia, is multifactorial and involves a complex interplay between host- and tumor-derived factors resulting in disrupted skeletal muscle function and metabolism (Jackman et al, 2017; Argiles et al, 2019). While dynamic exercise promotes metabolic and functional adaptations, mechanical stimulation of muscle involving passive movement (i.e., stretch) can produce important functional adaptations (Carson et al, 1995; Carson, 1997; De Deyne, 2001; Zöllner et al, 2012; Schiaffino et al, 2013; Hardee et al, 2016). Critical gaps remain in our knowledge of how tumor-derived cachectic factors influence mechanotransduction in cachectic muscle. It is not well understood if mechanical stimulation can induce. A better understanding of how increased mechanotransduction may elicit beneficial effects on cancer-induced muscle wasting is necessary

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