Introduction: Pancreatic ductal adenocarcinoma (PDAC) is the third leading cause of cancer-related deaths and frequently leads to PDAC-induced skeletal muscle wasting (SMW). Increased systemic levels of insulin-like growth factor-binding protein 3 (IGFBP-3) is associated with skeletal muscle loss in murine models of PDAC. Recent work from our lab demonstrated significant improvements in skeletal muscle mass in mice with orthotopic PDAC tumors lacking IGFBP-3. While much evidence suggests a link between mitochondrial dysfunction and cancer-induced SMW, the effects of tumor-derived IGFBP-3 on skeletal muscle mitochondrial function remain unclear. Here, we investigated the relationship among tumor-derived IGFBP-3, mitochondrial dysfunction, and PDAC-induced SMW using a mitochondria focused transcriptomic analysis. Methods: Ptf1atm1(cre)Cvw/WT; Kras tm4Tyj/WT; Trp53tm5Tyj/tm5Tyj (KP2) PDAC tumor cells underwent genetic deletion of the IGFBP-3 gene using a CRISPR/Cas9 system. Female C57Bl/6 mice were randomized to one of three treatment groups (n=3); 1) non-tumor control (NTC), 2) orthotopically injected with KP2 parental tumor cells (KP2) or 3) orthotopically injected with IGFBP-3 null tumor cells (IGFBP-3-/-) animals were sacrificed at URMC’s IACUC’s definition of failure to thrive and quadriceps muscles were harvested for bulk RNA sequencing and Fast Gene Set Enrichment Analysis (fGSEA). Longitudinal sections of tibialis anterior muscle from NTC, KP2, and IGFBP-3-/- mice were analyzed by transmission electron microscopy (TEM) for mitochondrial morphology. Mitochondrial superoxide was measured using Mitosox Red and MitoTracker Green FM in differentiated C2C12 myotubes after 24hours of treatment with 50% conditioned media from cultured KP2 and IGFBP-3-/- tumor cells. Results: We identified 2406 upregulated and 2137 downregulated differentially expressed genes (DEG) in the skeletal muscle of KP2 mice (P < 0.05), compared with 128 upregulated and 16 downregulated DEGs in the IGFBP-3-/- mice (P < 0.05). To further define transcriptomic changes in the absence of tumor-derived IGFBP-3, we directly compared the KP2 and IGFBP-3-/- gene expression and identified 1977 upregulated and 2025 downregulated DEG in the KP2 tumor-bearing group compared to the IGFBP-3-/- group (P < 0.05). An fGSEA of the IGFBP-3-/- vs KP2 DEGs revealed that 7 of the top 10 significantly downregulated pathways were related to mitochondrial function. Using the MitoCarta3.0 database to perform a focused mitochondrial transcriptomic analysis, we identified 69 upregulated and 118 downregulated mitochondrial DEGs in KP2 mouse muscle, while the IGFBP-3-/- mouse muscle had only a single downregulated mitochondrial DEG relative to NTC (P < 0.05). These mitochondrial DEGs in the KP2 muscle were primarily associated with lipid metabolism, mitochondrial RNA (mtRNA) metabolism, and mitochondrial translation. Consistent with these transcriptomic changes, TEM revealed a distinct alteration in mitochondrial morphology and increased lipid droplet accumulation in KP2 muscle, that was absent in the IGFBP-3-/- muscle. Additionally, C2C12 myotubes treated with KP2 conditioned media exhibited a significant increase in mitochondrial superoxide production when compared to both control (P < 0.001) and IGFBP-3-/- media (P < 0.01). Conclusions: Together, these findings demonstrate that the absence of tumor-derived IGFBP-3 attenuates PDAC-induced SMW which is associated with improvements in mitochondrial function in murine skeletal muscle. This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.
Belcher et al. (Fri,) studied this question.