INOS regulates the therapeutic response of pancreatic cancer cells to radiotherapy A C

Patricia M.R. Pereira, Kimberly J. Edwards, Komal Mandleywala, Lukas M. Carter, Freddy E. Escorcia, Luis Felipe Campesato, Mike Cornejo, Lolkje Abma, Abu Akeel Mohsen, Christine A. Iacobuzio-Donahue, Taha Merghoub, Jason S. Lewis

Research output: Contribution to journalArticlepeer-review

29 Scopus citations


Pancreatic ductal adenocarcinoma (PDAC) is highly resistant to radiotherapy, chemotherapy, or a combination of these modalities, and surgery remains the only curative intervention for localized disease. Although cancer-associated fibroblasts (CAF) are abundant in PDAC tumors, the effects of radiotherapy on CAFs and the response of PDAC cells to radiotherapy are unknown. Using patient samples and orthotopic PDAC biological models, we showed that radiotherapy increased inducible nitric oxide synthase (iNOS) in the tumor tissues. Mechanistic in vitro studies showed that, although undetectable in radiotherapy-activated tumor cells, iNOS expression and nitric oxide (NO) secretion were significantly increased in CAFs secretome following radiotherapy. Culture of PDAC cells with conditioned media from radiotherapy-activated CAFs increased iNOS/NO signaling in tumor cells through NF-kB, which, in turn, elevated the release of inflammatory cytokines by the tumor cells. Increased NO after radiotherapy in PDAC contributed to an acidic microenvironment that was detectable using the radiolabeled pH (low) insertion peptide (pHLIP). In murine orthotopic PDAC models, pancreatic tumor growth was delayed when iNOS inhibition was combined with radiotherapy. These data show the important role that iNOS/NO signaling plays in the effectiveness of radiotherapy to treat PDAC tumors. Significance:Aradiolabeled pH-targeted peptide can be used as a PET imaging tool to assess therapy response within PDAC and blocking iNOS/NO signaling may improve radiotherapy outcomes.

Original languageEnglish
Pages (from-to)1681-1692
Number of pages12
JournalCancer research
Issue number8
StatePublished - Apr 15 2020


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