Dense stroma activates the TGF-β1/FBW7 axis to induce metabolic subtype switching in pancreatic cancer.

[BACKGROUND] Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal diseases. Although several chemotherapy regimens have been developed over the past decades, few targeted therapies have shown a significant improvement in overall survival, partly due to the identification of PDAC as a single disease.

[METHODS] Combining metabolomic analysis and immunohistochemistry staining with Oil Red O staining, analysis for the oxygen consumption rate and extracellular acidification rate, we stratified pancreatic cancer cells into two subtypes. The impact of transforming growth factor β (TGF-β)-1/F-box and WD repeat domain-containing 7 (FBW7) on the switch of the metabolic subtype was further validated in vitro and in vivo . Finally, cell growth was performed to identify the TGF-β1/FBW7 ratio as a molecular marker for gemcitabine resistance.

[RESULTS] PDAC was stratified into the glycolytic subtype and lipogenic subtype. Furthermore, pancreatic cancer-associated fibroblasts-derived TGF-β1 and tumor cell-derived FBW7 were demonstrated to co-determine the metabolic phenotypes in PDAC. A high TGF-β1/FBW7 ratio always represented the glycolytic PDAC with dense stroma. This subtype of PDAC exhibited mesenchymal features and was predictive of unfavorable prognoses, despite being more sensitive than the lipogenic subtype to combination treatment with gemcitabine and an inhibitor of TGF-β receptor I (TGF-βR1).

[CONCLUSIONS] The TGF-β1/FBW7 ratio could be regarded as a molecular marker of metabolic phenotypes in PDAC and may contribute to the development of effective therapeutic strategies to improve the survival of PDAC patients.