title: Glutamate receptor GRIA3--target of CUX1 and mediator of tumor progression in pancreatic cancer.
abstract: Previously, we identified the transcription factor CUX1 as an important modulator of invasion and resistance to apoptosis. Expression profiles suggested that CUX1 regulates a complex transcriptional program mediating tumor progression. We aimed to identify functionally relevant targets of CUX1 by using RNA interference (RNAi)-based loss-of-function screens. Therefore, we generated an RNAi library containing putative transcriptional targets of CUX1 identified by microarrays and performed cell viability screens. Using this approach, several CUX1 targets with effect on tumor cell viability were identified, including the glutamate receptor GRIA3, which was validated in detail for its effects on proliferation, apoptosis, and cell migration using RNAi knock-down and overexpression strategies in vitro, as well as xenograft models in vivo. The expression of GRIA3 was evaluated in human pancreatic cancer tissues. We found that knock-down of GRIA3 significantly reduced proliferation and migration and enhanced apoptosis. In contrast, overexpression of GRIA3 significantly reduced apoptosis and enhanced both proliferation and tumor cell migration. GRIA3 could be confirmed as a downstream effector of CUX1 and was expressed in pancreatic cancer tissues. In vivo, GRIA3 significantly enhanced the growth of subcutaneous xenografts. Inhibitors of glutamate receptors such as GYKI52466 and SYM2206 significantly decreased survival of pancreatic cancer cells, suggesting the presence of glutamate signaling in pancreatic cancer. In conclusion, GRIA3 plays a role as a mediator of tumor progression in pancreatic cancer downstream CUX1. To our knowledge, this is the first report to identify a glutamate receptor as a modulator of tumor progression in a solid cancer outside the brain.
authors.affiliation: Department of Gastroenterology, University Hospital, Philipps University, Marburg, Germany.
authors.forename: Stefanie
authors.initials: S
authors.lastname: Ripka
authors.forename: Jan
authors.initials: J
authors.lastname: Riedel
authors.forename: Albrecht
authors.initials: A
authors.lastname: Neesse
authors.forename: Heidi
authors.initials: H
authors.lastname: Griesmann
authors.forename: Malte
authors.initials: M
authors.lastname: Buchholz
authors.forename: Volker
authors.initials: V
authors.lastname: Ellenrieder
authors.forename: Franz
authors.initials: F
authors.lastname: Moeller
authors.forename: Peter
authors.initials: P
authors.lastname: Barth
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Gress
authors.forename: Patrick
authors.initials: P
authors.lastname: Michl
mesh_terms: D000230:Adenocarcinoma / Q000235:genetics* / Q000473:pathology; D000818:Animals; D002465:Cell Movement / Q000187:drug effects / Q000235:genetics; D002470:Cell Survival / Q000187:drug effects / Q000235:genetics; D018450:Disease Progression; D005260:Female; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D018398:Homeodomain Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D006801:Humans; D051379:Mice; D008819:Mice, Nude; D009361:Neoplasm Invasiveness; D009687:Nuclear Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D020411:Oligonucleotide Array Sequence Analysis; D009857:Oncogenes / Q000235:genetics / Q000502:physiology; D010190:Pancreatic Neoplasms / Q000235:genetics* / Q000473:pathology; D034622:RNA Interference / Q000502:physiology; D018091:Receptors, AMPA / Q000235:genetics* / Q000502:physiology*; D012097:Repressor Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D014157:Transcription Factors; D014183:Transplantation, Heterologous; D014407:Tumor Cells, Cultured
chemical_list: C080632:CUX1 protein, human; D018398:Homeodomain Proteins; D009687:Nuclear Proteins; D018091:Receptors, AMPA; D012097:Repressor Proteins; D014157:Transcription Factors; C104723:glutamate receptor ionotropic, AMPA 3