Diabetes Fuels Pancreatic Cancer by Aging Blood Vessel Cells Prematurely

Pancreatic ductal adenocarcinoma (PDAC) has a dismal 5-year survival rate, and approximately 35–50% of patients carry comorbid diabetes. Clinical analysis of two independent cohorts—MSK-IMPACT (386 resectable PDAC patients) and the Xijing Hospital cohort (268 patients)—confirmed that diabetes is an independent predictor of worse overall survival by multivariate Cox regression, even after controlling for age, sex, tumor stage, CA199, and other comorbidities. Preoperative hyperglycemia alone did not fully explain the survival gap, suggesting that broader systemic metabolic dysfunction in diabetes is responsible.

To dissect the underlying biology, the researchers constructed orthotopic pancreatic tumor models in C57BL/6J mice fed a high-fat diet (HFD) with or without streptozotocin (STZ) to induce type 2 diabetes-like hyperglycemia. Diabetic tumor-bearing mice (HFD+STZ) developed significantly larger, heavier tumors than normoglycemic controls, and insulin treatment to normalize blood glucose partially reversed this effect—demonstrating that hyperglycemia contributes but is not the sole driver. Single-cell RNA sequencing (scRNA-seq) and bulk transcriptomics of tumor microenvironments revealed a marked expansion of a senescent endothelial cell subpopulation specifically in diabetic tumors. These cells upregulated canonical senescence markers (p16, p21, SA-β-gal activity, γH2AX foci) and displayed a robust SASP signature.

Among SASP factors elevated in diabetic tumor endothelial cells, INHBB—a member of the TGF-β superfamily encoding the inhibin beta-B subunit—emerged as a top candidate. INHBB expression was significantly higher in diabetic tumor endothelium and was regulated by Notch signaling; pharmacological or genetic inhibition of Notch reduced INHBB secretion. Recombinant INHBB promoted PDAC cell proliferation, migration, and invasion in vitro, while INHBB knockdown in endothelial cells attenuated tumor-promoting paracrine effects. Mechanistically, INHBB activated Smad2/3 signaling in pancreatic cancer cells.

Therapeutically, the authors tested bimagrumab, a clinically evaluated monoclonal antibody targeting activin receptor type II (ActRII)—the receptor for INHBB—originally developed for muscle wasting and obesity. Bimagrumab significantly inhibited tumor growth in diabetic orthotopic mouse models. Importantly, short-term bimagrumab treatment did not significantly lower blood glucose in diabetic tumor-bearing mice, addressing a potential concern about metabolic side effects. Combining bimagrumab with metformin (a first-line diabetes drug with known antitumor properties) produced synergistic suppression of tumor growth, offering a rationale for combination therapy tailored to PDAC patients with diabetes.

This work positions senescent tumor endothelial cells and their SASP factor INHBB as a previously unrecognized, therapeutically actionable axis linking diabetes to PDAC aggressiveness. It also highlights the potential of repurposing bimagrumab—already in clinical trials for other indications—for this high-risk patient subgroup, and supports the concept of individualized oncology strategies based on metabolic comorbidities.