title: Polyphenols from marine brown algae target radiotherapy-coordinated EMT and stemness-maintenance in residual pancreatic cancer.
abstract: BACKGROUND
  Therapy-associated onset of stemness-maintenance in surviving tumor-cells dictates tumor relapse/recurrence. Recently, we recognized the anti-pancreatic cancer (PC) potential of seaweed polyphenol manifolds and narrowed down three superior drug-deliverables that could serve as adjuvants and benefit PC cure. Utilizing the PC- cancer stem cells (PC-CSCs) grown ex vivo and mouse model of residual-PC, we investigated the benefits of seaweed polyphenols in regulating stemness-maintenance.
  
  
  METHODS
  ALDH(+)CD44(+)CD24(+) PC-CSCs from Panc-1, Panc-3.27, MiaPaCa-2, or BxPC-3 cells-derived xenografts grown ex vivo were either mock-irradiated, exposed to fractionated irradiation (FIR, 2Gy/D for 5 days), treated with polyphenols (100 μg/ml) of Hormophysa triquerta (HT-EA), Spatoglossum asperum (SA-EA) or Padina tetrastromatica (PT-EA) with/without FIR were examined for cell viability, transcription of 93 stem-cell-related molecules (QPCR profiling). Polyphenol-dependent regulation of FIR-transactivated Oct4, Zic3, EIF4C, Nanog, and LIF (QPCR) and functional translation of Nanog, SOX2, and OCT3/4 (immunoblotting) were examined in Panc-1/Panc-3.27/MiaPaCa-2/BxPC-3-xenografts derived PC-CSCs. Effect of seaweed-polyphenols in the regulation of EMT (N-Cadherin), pluripotency- (SOX2, OCT3/4, Nanog) and stemness-maintenance (PI3KR1, LIF, CD44) in therapy (FIR, 2Gy/D for 5D/wk for 3-weeks) resistant residual tumors were examined by tissue microarray construction and automated immunohistochemistry.
  
  
  RESULTS
  Ex vivo exposure of PC-CSCs to SA-EA, PT-EA and HT-EA exhibit dose-dependent inhibition of cell viability. FIR amplified the transcription of 69, 80, 74 and 77 stem-cell related genes in MiaPaCa-2-, Panc-1-, Panc-3.27- and BXPC3-established xenograft-derived ALDH(+)CD44(+)CD24(+)PC-CSCs. Treatment with SA-EA, PT-EA, or HT-EA completely suppressed FIR-activated stem-cell transcriptional machinery in ALDH(+)CD44(+)CD24(+)PC-CSCs established from MiaPaCa-2, Panc-1, Panc-3.27 and BXPC3 xenografts. QPCR validated EIF4C, OCT3/4, Nanog, LIF, and ZIC3 transcriptional profile outcomes. Nanog, Sox2, and OCT3/4 immunoblotting affirmed the PC-CSC radiosensitizing benefit of seaweed polyphenols. Residual-PC tissues microarrayed and immunostained after in vivo treatments recognized complete regulation of FIR-induced SOX2, OCT3/4, Nanog, LIF, CD44, PIK3R1, N-Cadherin, and E-Cadherin with SA-EA, PT-EA, and HT-EA.
  
  
  CONCLUSIONS
  These data, for the first time, documented the EMT/stemness-maintenance in therapy-resistant PC-CSCs. Further, the data suggest that seaweed polyphenols may inhibit PC relapse/recurrence by targeting therapy-orchestrated stem-cell signaling in residual cells.
authors.affiliation: Department of Marine Sciences, Center of Advance Study in Marine Biology, Annamalai University, Parangipettai, TN, 608 502, India. saravind@ouhsc.edu.|Stephenson Cancer Center, 975 NE 10th Street, Oklahoma City, OK, 73104-5419, USA. saravind@ouhsc.edu.
authors.forename: Sheeja
authors.initials: S
authors.lastname: Aravindan
authors.affiliation: Department of Radiation Oncology, University of Oklahoma Health Sciences Center, 940 Stanton L. Young Boulevard, Oklahoma City, OK, 73104, USA. sramraj@ouhsc.edu.
authors.forename: Satish Kumar
authors.initials: SK
authors.lastname: Ramraj
authors.affiliation: Department of Marine Sciences, Center of Advance Study in Marine Biology, Annamalai University, Parangipettai, TN, 608 502, India. drstscas@yahoo.com.
authors.forename: Somasundaram T
authors.initials: ST
authors.lastname: Somasundaram
authors.affiliation: Department of Radiation Oncology, University of Oklahoma Health Sciences Center, 940 Stanton L. Young Boulevard, Oklahoma City, OK, 73104, USA. therman@ouhsc.edu.
authors.forename: Terence S
authors.initials: TS
authors.lastname: Herman
authors.affiliation: Department of Radiation Oncology, University of Oklahoma Health Sciences Center, 940 Stanton L. Young Boulevard, Oklahoma City, OK, 73104, USA. naravind@ouhsc.edu.
authors.forename: Natarajan
authors.initials: N
authors.lastname: Aravindan
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D058750:Epithelial-Mesenchymal Transition / Q000187:drug effects / Q000528:radiation effects; D006801:Humans; D008297:Male; D051379:Mice; D008819:Mice, Nude; D018365:Neoplasm, Residual / Q000188:drug therapy / Q000473:pathology / Q000532:radiotherapy; D014411:Neoplastic Stem Cells / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D018384:Oxidative Stress / Q000187:drug effects; D010190:Pancreatic Neoplasms / Q000188:drug therapy* / Q000473:pathology / Q000532:radiotherapy; D000459:Phaeophyceae / Q000737:chemistry*; D059808:Polyphenols / Q000302:isolation & purification* / Q000494:pharmacology*; D014158:Transcription, Genetic / Q000187:drug effects / Q000528:radiation effects; D023041:Xenograft Model Antitumor Assays
chemical_list: D059808:Polyphenols