title: Minnelide effectively eliminates CD133(+) side population in pancreatic cancer.
abstract: BACKGROUND
  Pancreatic Ductal Adenocarcinoma (PDAC) is a devastating disease hallmarked by limited patient survival. Resistance to chemotherapy, a major cause of treatment failure in PDAC patients, is often attributed to Cancer Stem Cells (CSCs). Pancreatic CSCs are a small subset of quiescent cells within a tumor represented by surface markers like CD133. These cells are responsible not only for tumor recurrence, but also poor prognosis based on their "stem-like" characteristics. At present, conventional therapy is directed towards rapidly dividing PDAC cells and thus fails to target the CSC population.
  
  
  METHODS
  MIA PaCa-2, S2-013 and AsPC-1 were treated with 12.5 nM triptolide (12 T cells) for 7 days. The surviving cells were recovered briefly in drug-free growth media and then transferred to Cancer Stem cell Media (CSM). As a control, untreated cells were also transferred to CSM media (CSM). The 12 T and CSM cells were tested for stemness properties using RNA and protein markers. Low numbers of CSM and 12 T cells were implanted subcutaneously in athymic nude mice to study their tumorigenic potential. 12 T and CSM cells were sorted for CD133 expression and assayed for their colony forming ability and sphere forming ability. Invasiveness of 12 T cells, CSM and MIA PaCa-2 were compared using Boyden chamber assays.
  
  
  RESULTS
  Treated 12 T cells displayed increased expression of the surface marker CD133 and the drug transporter ABCG2 compared to untreated cells (CSM cells). Both 12 T and CSM cells formed subcutaneous tumors in mice confirming their tumor-initiating properties. When tested for invasion, 12 T cells had increased invasiveness compared to CSM cells. CD133(+) cells in both CSM and 12 T showed greater colony and sphere forming ability compared to CD133(-) cells from each group. Consistent with these data, when injected subcutaneously in mice, CD133(-) cells from CSM or 12 T did not form any tumors whereas CD133(+) cells from both groups showed tumor formation at a very low cell number. Despite pre-exposure to triptolide in 12 T CD133(+) cells, treatment of tumors formed by these cells with Minnelide, a triptolide pro-drug, showed significant tumor regression.
  
  
  CONCLUSIONS
  Our results indicated that triptolide enhanced and enriched the "stemness" in the PDAC cell lines at a low dose of 12.5 nM, but also resulted in the regression of tumors derived from these cells.
authors.affiliation: Department of Surgery, Division of Basic and Translational Research, University of Minnesota, Minneapolis, MN, 55455, USA.
authors.forename: Alice
authors.initials: A
authors.lastname: Nomura
authors.affiliation: Department of Surgery, Division of Basic and Translational Research, University of Minnesota, Minneapolis, MN, 55455, USA.
authors.forename: Olivia
authors.initials: O
authors.lastname: McGinn
authors.affiliation: Department of Surgery, Division of Basic and Translational Research, University of Minnesota, Minneapolis, MN, 55455, USA.
authors.forename: Vikas
authors.initials: V
authors.lastname: Dudeja
authors.affiliation: Department of Surgery, Division of Basic and Translational Research, University of Minnesota, Minneapolis, MN, 55455, USA.
authors.forename: Veena
authors.initials: V
authors.lastname: Sangwan
authors.affiliation: Department of Surgery, Division of Basic and Translational Research, University of Minnesota, Minneapolis, MN, 55455, USA.|Masonic Cancer Center, University of Minnesota, Minneapolis, MN, USA.
authors.forename: Ashok K
authors.initials: AK
authors.lastname: Saluja
authors.affiliation: Department of Surgery, Division of Basic and Translational Research, University of Minnesota, Minneapolis, MN, 55455, USA. sbanerje@umn.edu.|Masonic Cancer Center, University of Minnesota, Minneapolis, MN, USA. sbanerje@umn.edu.
authors.forename: Sulagna
authors.initials: S
authors.lastname: Banerjee
mesh_terms: D000071916:AC133 Antigen; D015703:Antigens, CD / Q000378:metabolism*; D000970:Antineoplastic Agents / Q000494:pharmacology*; D021441:Carcinoma, Pancreatic Ductal / Q000188:drug therapy* / Q000473:pathology; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004224:Diterpenes / Q000494:pharmacology; D019008:Drug Resistance, Neoplasm; D004354:Drug Screening Assays, Antitumor; D004852:Epoxy Compounds / Q000494:pharmacology; D006023:Glycoproteins / Q000378:metabolism*; D006801:Humans; D014411:Neoplastic Stem Cells / Q000187:drug effects / Q000502:physiology; D010755:Organophosphates / Q000494:pharmacology*; D010190:Pancreatic Neoplasms / Q000188:drug therapy* / Q000473:pathology; D010455:Peptides / Q000378:metabolism*; D010616:Phenanthrenes / Q000494:pharmacology*; D058985:Side-Population Cells / Q000187:drug effects
chemical_list: D000071916:AC133 Antigen; D015703:Antigens, CD; D000970:Antineoplastic Agents; D004224:Diterpenes; D004852:Epoxy Compounds; D006023:Glycoproteins; D010755:Organophosphates; C000606023:PROM1 protein, human; D010455:Peptides; D010616:Phenanthrenes; C000606024:Prom1 protein, mouse; C001899:triptolide; C579022:14-O-phosphonooxymethyltriptolide disodium salt