Carnosol attenuated atrophy of C2C12 myotubes induced by tumour‐derived exosomal miR‐183‐5p through inhibiting Smad3 pathway activation and keeping mitochondrial respiration

Abstract

Cancer-derived exosomes are involved in the development of cancer cachexia.Carnosol, which exhibited ameliorating effects on cancer cachexia of C26 tumour-bearing mice in our previous study, alleviated atrophy of C2C12 myotubes induced by exosomes of C26 tumour cells in the present study. MiR-183-5p was found to be rich in C26 cells and C26 exosomes, and miR-183-5p mimic could directly induce atrophy of C2C12 myotubes. Carnosol at 5 to 20 μM could dose-dependently ameliorate the myotube atrophy induced by miR-183-5p. Four and a half LIM domain protein 1 (FHL1) was shown to be the direct target of miR-183-5p. Increase in myostatin, p-Smad3, MuRF-1, Atrogin-1, HIF-1α and p-STAT3 and decrease in mitochondrial respiration were also induced by miR-183-5p mimic in C2C12 myotubes. Carnosol could not affect the decrease in FHL-1 and the activation of STAT3 pathway but could significantly alleviate the increase in myostatin, p-Smad3, MuRF-1, Atrogin-1 and the decrease in mitochondrial respiration induced by miR-183-5p. The protective effects of carnosol on myotubes against atrophy of C2C12 myotubes induced by miR-183-5p, based on both its inhibiting effects on MuRF-1 and Atrogin-1-mediated protein degradation and its ability of keeping the mitochondrial respiration, might contribute to its ameliorating effects on cancer cachexia.

The role of extracellular vesicles in skeletal muscle wasting

“…The reason is that the levels of miR‐195a‐5p and miR‐125b‐1‐3p in C26 EVs were much higher than those in MC38 EVs, as confirmed by miRNA‐seq data 48 . In another study, the same group reported another colon cancer cell‐derived EV‐associated miRNA named miR‐183‐5p could also induce myotube protein degradation 49 . By targeting FHL1, miR183‐5p activates the myostatin/Smad3 pathway, thus promoting muscle proteolysis mediated by Atrogin‐1 and MuRF‐1, canonical regulators of the ubiquitin‐proteasome pathway 49 .…”

“…And it was found that skeletal muscle wasting could also be induced by angiotensin II, so the FDA‐approved drug losartan could be used to provide protection against muscle wasting 77,78 . Carnosol, an active component of the herbal medicine rosemary, has the ability to attenuate muscle loss induced by EVs 49 . Glycyrrhizin, an inhibitor of HMGB1, can be used as a potential drug to alleviate muscle wasting 57 .…”

Extracellular vesicles in cancer cachexia: deciphering pathogenic roles and exploring therapeutic horizons

“…Additionally, tumor-derived EVs can exacerbate cachexia by sending pro-cachectic signals to distant tissues. Therapeutically, targeting these tumor-derived EVs [ 198 – 201 ] or blocking their pathway activation [ 43 , 56 , 67 ] can mitigate cachexia-related complications. For example, amiloride, a commonly used diuretic, significantly improves metabolic disorders in cachectic gastrocnemius by effectively inhibiting tumor-derived exosome release, thus affecting muscle catabolism, protein synthesis, glycolysis, and ketone body oxidation [ 201 ].…”

Exosomes in the pathogenesis and treatment of cancer-related cachexia

“…An enrichment of miR-183-5p was observed in C26 cells and C26 exosomes. Furthermore, the induction of muscle duct atrophy in C2C12 cells by miR-183-5p mimics was accompanied by increased expression of Atrogin-1, MuRF-1, myostatin, HIF-1α, p-SMAD3, and p-STAT3, along with decreased mitochondrial respiration [ 97 ]. Four and a half LIM domain protein 1 (FHL1) plays a role in muscle growth, differentiation, and myomas formation, and it is also recognized as a regulator of skeletal muscle mass.…”

“…Additionally, FHL1 gene has been identified as a direct target of miR-183-5p. By reducing the expression of Atrogin-1, MuRF-1, and myostatin, inhibiting the activation of the Smad3 pathway, and preserving the mitochondrial respiration, Carnosol has a protective effect on mir-183-5p-induced muscular tube atrophy of C2C12 cells [ 97 ].…”