A temporally regulated miRNA signature in pancreatic cancer extracellular vesicles disrupts the circadian clock and promotes muscle atrophy

Pancreatic ductal adenocarcinoma (PDAC) carries a dismal prognosis, aggravated by cachexia, a systemic wasting syndrome whose molecular mediators remain incompletely defined. Circadian disruption is a further hallmark of PDAC, yet a shared mechanistic basis between these two features has not been established. Here we show that the PDAC secretome, and the small extracellular vesicles (sEVs) it carries, are sufficient to disrupt the circadian clock in independent reporter cell lines and in differentiated myotubes, and to induce myotube atrophy. PANC-1 sEV release and miRNA cargo display pronounced time-of-day variation, with the cargo resolving into two functionally distinct pools: a rhythmically secreted subset, whose release is phase-coordinated and which transmits time-of-day information to the recipient tissue, and a constitutively secreted subset that, although non-rhythmic at the source, is itself capable of perturbing the recipient circadian clock. Individual miRNAs drawn from both pools exert distinct and non-redundant effects on circadian period and myotube diameter. Seahorse extracellular flux analysis further reveals that these miRNAs reprogram mitochondrial respiration and substrate utilization along three divergent trajectories, energetic, high-metabolic, and glycolytic, rather than along a single bioenergetic axis. Intersecting the tumor sEV secretome with serum sEV miRNAs from a pancreatic cancer patient cohort and with the miRNA-Seq landscape of 495 PDAC tumors defines a stable, broadly tumor-abundant, patient-detectable miRNA signature that collectively regulates circadian, proteostatic, and cachexia-relevant gene networks. Across these orthogonal datasets, hsa-miR-27b-3p emerges as a node within the rhythmically secreted pool: consistently detected in patient serum, ranked among the top 50 most abundant miRNAs in >90% of these tumors, and individually sufficient to shorten the circadian period, drive myotube atrophy comparable to dexamethasone, and impose an energetic mitochondrial phenotype. Together, these findings identify PDAC sEV miRNAs as temporally organized mediators coupling circadian disruption, muscle bioenergetics, and cachexia-relevant muscle reprogramming.