title: Up-regulation of microRNA let-7c by quercetin inhibits pancreatic cancer progression by activation of Numbl.
abstract: Pancreatic Ductal Adenocarcinoma (PDA) is a highly malignant tumor with poor prognosis. MicroRNAs (miRs) may offer novel therapeutic approaches to treatment. The polyphenol quercetin, present in many fruits and vegetables, possesses anti-carcinogenic properties. To unravel the effect of quercetin to miR signaling we performed miR profiling in PDA cells before and after quercetin treatment, followed by biostatistical analysis. miR let-7c was among the top up-regulated candidates after quercetin treatment, as measured by qRT-PCR and confirmed in two established and one primary PDA cell lines. By computational analysis we identified the Notch-inhibitor Numbl as let-7c target gene. This was strengthened by luciferase assays, where lipofected let-7c mimics induced a Numbl 3-UTR wild type construct, but not the mutated counterpart. Let-7c induced Numbl mRNA and protein expression but inhibited Notch just like quercetin. It also inhibited colony formation, wound healing, and protein expression of progression markers. In vivo xenotransplantation of PDA cells and subsequent intravenous injection of let-7c resulted in a significant decrease in tumor mass without obvious toxic effects in the fertilized chick egg model. The delivery rate of the miR mimics to the tumor mass was 80%, whereas minor amounts were present in host tissue. By immunohistochemistry we demonstrated that let-7c inhibited Notch and progression markers but up-regulated Numbl. These findings show that quercetin-induced let-7c decreases tumor growth by posttranscriptional activation of Numbl and indirect inhibition of Notch.
authors: Team Molecular OncoSurgery, Section Surgical Research, Department of General, Visceral and Transplantation Surgery, University of Heidelberg, Heidelberg, Germany.
authors: Clifford C
authors: CC
authors: Nwaeburu
authors: Team Molecular OncoSurgery, Section Surgical Research, Department of General, Visceral and Transplantation Surgery, University of Heidelberg, Heidelberg, Germany.
authors: Natalie
authors: N
authors: Bauer
authors: Team Molecular OncoSurgery, Section Surgical Research, Department of General, Visceral and Transplantation Surgery, University of Heidelberg, Heidelberg, Germany.
authors: Zhefu
authors: Z
authors: Zhao
authors: Team Molecular OncoSurgery, Section Surgical Research, Department of General, Visceral and Transplantation Surgery, University of Heidelberg, Heidelberg, Germany.
authors: Alia
authors: A
authors: Abukiwan
authors: Team Molecular OncoSurgery, Section Surgical Research, Department of General, Visceral and Transplantation Surgery, University of Heidelberg, Heidelberg, Germany.
authors: Jury
authors: J
authors: Gladkich
authors: Department of Biostatistics, German Cancer Research Center (DKFZ), Heidelberg, Germany.
authors: Axel
authors: A
authors: Benner
authors: Team Molecular OncoSurgery, Section Surgical Research, Department of General, Visceral and Transplantation Surgery, University of Heidelberg, Heidelberg, Germany.
authors: Ingrid
authors: I
authors: Herr
mesh_terms: D020413:3' Untranslated Regions; D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology; D002642:Chick Embryo; D019295:Computational Biology; D018450:Disease Progression; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D035683:MicroRNAs / Q000378:metabolism*; D009368:Neoplasm Transplantation; D014411:Neoplastic Stem Cells; D010006:Osteoblasts / Q000378:metabolism; D010190:Pancreatic Neoplasms / Q000235:genetics / Q000378:metabolism*; D011794:Quercetin / Q000494:pharmacology*; D051881:Receptor, Notch1 / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D015854:Up-Regulation
chemical_list: D020413:3' Untranslated Regions; D000972:Antineoplastic Agents, Phytogenic; D047908:Intracellular Signaling Peptides and Proteins; D035683:MicroRNAs; C497761:NOTCH1 protein, human; C530266:NUMBL protein, human; D051881:Receptor, Notch1; C487931:mirnlet7 microRNA, human; D011794:Quercetin
keywords: cancer; microRNA; phytochemicals; stem cell signaling