The c-Myc-USP14-PFKP axis sustains chemoresistance in pancreatic ductal adenocarcinoma.

BACKGROUND: Therapeutic resistance remains a major clinical challenge in pancreatic ductal adenocarcinoma (PDAC). Increasing evidence indicates that metabolic reprogramming contributes to PDAC progression and drug resistance; however, the oncogenic signaling associated with metabolism in chemo-resistant PDAC remains incompletely defined.

METHODS: Integrated single-cell transcriptomic analyses combined with bulk RNA sequencing were performed to identify candidate genes associated with metastasis, proliferation, and drug resistance in PDAC, leading to the prioritization of phosphofructokinase-platelet (PFKP), a rate-limiting glycolytic enzyme implicated in tumor metabolic adaptation. Functional and mechanistic studies were conducted in PDAC cell lines, patient-derived organoids, syngeneic models, and xenograft models. Protein stability, ubiquitination dynamics, and transcriptional regulation of PFKP were examined using biochemical, molecular, and pharmacological approaches. The therapeutic impact of combined PFKP suppression and USP14 inhibition was evaluated in clinically relevant in vivo models.

RESULTS: Integrated transcriptomic analyses identified PFKP as a candidate gene associated with aggressive tumor states and reduced chemotherapy responsiveness in PDAC. Elevated PFKP expression correlated with poor patient survival and diminished sensitivity to gemcitabine-based chemotherapy. Functional studies showed that PFKP supports tumor cell proliferation, migration, invasion, and chemoresistance. Mechanistically, the deubiquitinase USP14 contributed to the stabilization of PFKP protein through K48-linked deubiquitination. In parallel, c-Myc transcriptionally upregulated USP14, while PFKP was associated with enhanced ERK-dependent stabilization of c-Myc protein, together forming a regulatory feed-forward circuit. Disruption of the c-Myc/USP14/PFKP axis increased chemotherapy sensitivity in PDAC models, and combined targeting PFKP and USP14 resulted in enhanced antitumor effects in patient-derived organoids, syngeneic model, and xenograft models.

CONCLUSION: Our findings support the existence of a c-Myc-USP14-PFKP regulatory circuit that contributes to PDAC progression and chemoresistance. Targeting this axis may represent a promising strategy to enhance therapeutic responses in PDAC.