It remains unclear how obesity worsens treatment outcomes in patients with pancreatic ductal adenocarcinoma (PDAC).
In normal pancreas, obesity promotes inflammation and fibrosis. We found in mouse models of PDAC that obesity also promotes desmoplasia associated with accelerated tumor growth and impaired delivery/efficacy of chemotherapeutics through reduced perfusion.
Genetic and pharmacological inhibition of angiotensin-II type-1 receptor (AT1) reverses obesity-augmented desmoplasia and tumor growth and improves response to chemotherapy. Augmented activation of pancreatic stellate cells (PSCs) in obesity is induced by tumor-associated neutrophils (TANs) recruited by adipocyte-secreted IL-1ß. PSCs further secrete IL-1ß, and inactivation of PSCs reduces IL-1ß expression and TAN recruitment.
Furthermore, depletion of TANs, IL-1ß inhibition, or inactivation of PSCs prevents obesity-accelerated tumor growth.
In pancreatic cancer patients, we confirmed that obesity is associated with increased desmoplasia and reduced response to chemotherapy.
We conclude that crosstalk between adipocytes, TANs, and PSCs exacerbates desmoplasia and promotes tumor progression in obesity.