The Role of FoxP1 in Muscle Wasting During Cancer

Cancer cachexia is a common issue, affecting up to 80% of cancer patients. It reduces their quality of life and survival rates. Previously, it was shown that the transcriptional repressor Forkhead box P1 (FoxP1) is increased in the skeletal muscle of both cachectic mice and humans with cancer. When overexpressed, it can cause muscle wasting symptoms similar to cachexia. But the role of FoxP1 in normal muscle function and cancer-induced muscle wasting is not well understood. To explore this, researchers created a mouse line where FoxP1 was specifically deleted in skeletal muscle cells (FoxP1SkmKO ). In mice without cancer, deleting FoxP1 increased muscle fiber size in both males and females, with males showing a significant increase in overall muscle mass. When these mice were exposed to a pancreatic tumor, FoxP1 in muscle fibers was found to be crucial for the muscle wasting and weakness seen in the diaphragm of male mice. Overall, the study highlights that FoxP1 in muscle fibers negatively affects muscle growth, with varying impacts based on sex in the context of cancer.