Regulation of dynamin-related protein 1 (DRP1) levels modulates myoblast atrophy induced by C26 colon cancer-conditioned medium.

BACKGROUND: Cancer associated-cachexia, which involves progressive skeletal muscle loss, is induced by multiple factors. However, the underlying mechanism remains unclear. Dynamin-related protein 1 (DRP1), a major modulator of mitochondrial fission, has been reported to participate in muscle turnover. This study aimed to explore the role of DRP1 in muscle during the process of cancer associated-cachexia (CAC) via an in vitro model and the mechanisms involved. METHODS: C26 colon cancer cell-conditioned medium (CM) was used to incubate with C2C12 myotubes to simulate cachexia. Myotubes were then transduced with lentiviral vectors of DRP1-small interfering RNA (siRNA), DRP1 overexpression plasmid, or a control plasmid to regulate the DRP1 levels, and their diameters were assessed using a biological microscope. Furthermore, transcriptome sequencing was performed to screen the pathways involved, and real-time polymerase chain reaction (RT-PCR) was used for verification. RESULTS: The cachexia model was successfully established with a decreased myotube diameter and increased DRP1 expression. DRP1 knockdown significantly ameliorated myotube wasting during cachexia, while DRP1 overexpression intensified this phenomenon. Transcriptome sequencing indicated that DRP1 knockdown was associated with the activation of ribosomal biogenesis. However, PCR results showed that compared to the control, one of the ribosomal biogenesis marker's (Ubf) level was decreased by C26 CM, and DRP1 knockdown did not significantly restore its level. CONCLUSIONS: During C26 CM-induced cachexia, DRP1 was activated, while the regulation of DRP1 levels was able to modulate the atrophy of C2C12 myotubes. The underlying mechanism of the alleviated muscle atrophy induced by DRP1 knockdown was likely associated with increased ribosomal activity.