title: The radiosensitizing effects of Nelfinavir on pancreatic cancer with and without pancreatic stellate cells.
abstract: We have previously shown in a phase I trial that nelfinavir (NFV) is safe with chemoradiation in PDAC with good signs for efficacy. Reverse translationally, we aimed to test the influence of PSCs on nelfinavir mediated radiosensitization to PDAC preclinically, because PDAC is very rich in desmoplasia and PSCs are known to mediate radioresistance.
  
  
  
  In a direct co-culture model of several PDAC cell lines with PSC we performed clonogenic assays +/- nelfinavir. This was repeated exposing cells to hypoxic conditions. In xenograft PDAC tumors we tested radiation +/- nelfinavir +/- PSC.
  
  
  
  NFV sensitized both, PDAC only and PDAC cocultured with PSC (PDAC: Panc-1, MiaPaCa-2, PSN-1). In Panc-1 and PSN-1 this effect was larger +PSC compared to -PSC. Human pancreatic stellate cells (hPSC) were also sensitized by NFV which reduced p-FAK levels in hPSC, an effect that we previously found to sensitize specifically PDAC/PSC coculture. Contrarily, LY294002 reduced p-Akt in PSC (hPSC and LTC-14) but had no impact on PSC radiation survival. In vitro, nelfinavir sensitized Panc-1 and PSN-1 under normoxic and hypoxic conditions. In PSN-1 xenografts, +PSC led to faster tumor regrowth after radiation vs -PSC. The regrowth delay effect of nelfinavir after radiation was dramatically larger +PSC vs -PSC (time to reach 250mm(3) 183% vs 22%).
  
  
  
  NFV mediated radiosensitization in PDAC with stroma is partly mediated by p-FAK inhibition (Chen et al., 2013). In vitro, NFV sensitizes both normoxic and hypoxic PDAC +/- PSC to a roughly similar extent. The dramatic increased effect of xenograft regrowth inhibition by nelfinavir in tumors with PSC is attributed to vascular normalization (Brunner et al., 2014) rather than direct modification of hypoxia as shown by the tumor regrowth after gemcitabine with NFV.
authors.affiliation: CRUK/MRC Oxford Institute for Radiation Oncology, Heidelberg, Partner Site Freiburg, Germany.
authors.forename: Osama
authors.initials: O
authors.lastname: Al-Assar
authors.affiliation: CRUK/MRC Oxford Institute for Radiation Oncology, Heidelberg, Partner Site Freiburg, Germany; Dept. of Radiation Oncology Freiburg, Heidelberg, Partner Site Freiburg, Germany.
authors.forename: Martin-Immanuel
authors.initials: MI
authors.lastname: Bittner
authors.affiliation: CRUK/MRC Oxford Institute for Radiation Oncology, Heidelberg, Partner Site Freiburg, Germany.
authors.forename: Serena
authors.initials: S
authors.lastname: Lunardi
authors.affiliation: CRUK/MRC Oxford Institute for Radiation Oncology, Heidelberg, Partner Site Freiburg, Germany.
authors.forename: Michael R
authors.initials: MR
authors.lastname: Stratford
authors.affiliation: CRUK/MRC Oxford Institute for Radiation Oncology, Heidelberg, Partner Site Freiburg, Germany.
authors.forename: W Gillies
authors.initials: WG
authors.lastname: McKenna
authors.affiliation: CRUK/MRC Oxford Institute for Radiation Oncology, Heidelberg, Partner Site Freiburg, Germany; Dept. of Radiation Oncology Freiburg, Heidelberg, Partner Site Freiburg, Germany; German Cancer Consortium (DKTK), Heidelberg, Partner Site Freiburg, Germany. Electronic address: thomas.brunner@uniklinik-freiburg.de.
authors.forename: Thomas B
authors.initials: TB
authors.lastname: Brunner
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D004195:Disease Models, Animal; D005260:Female; D017320:HIV Protease Inhibitors / Q000494:pharmacology*; D051379:Mice; D008819:Mice, Nude; D019888:Nelfinavir / Q000494:pharmacology*; D010190:Pancreatic Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D058954:Pancreatic Stellate Cells / Q000187:drug effects*; D011838:Radiation-Sensitizing Agents / Q000494:pharmacology*
chemical_list: D017320:HIV Protease Inhibitors; D011838:Radiation-Sensitizing Agents; D019888:Nelfinavir
keywords: Hypoxia; Nelfinavir; Pancreatic cancer; Pancreatic stellate cells; Radiotherapy