title: Peanut-like 1 (septin 5) gene expression in normal and neoplastic human endocrine pancreas.
abstract: Peanut-like 1 (PNUTL1) is a septin gene which is expressed at high levels in human brain. There it plays a role in the process of membrane fusion during exocytosis by interacting with syntaxin and synaptophysin. As the secretory apparatus of pancreatic islet cells closely resembles that of neurons, we decided to study the expression of PNUTL1 in the human endocrine pancreas, both in normal islets and in pancreatic endocrine tumors (PETs). Normal pancreatic tissue, purified islets, 11 PETs and two cell lines were used to evaluate the presence of PNUTL1 by RT-PCR and Western blot. The expression of the PNUTL1 protein was also evaluated by immunohistochemistry on normal pancreas, additional 26 PETs, eight pancreatic adenocarcinomas, one mixed endocrine-exocrine pancreatic neoplasm, a specimen of solid papillary pseudomucinous tumor, an adult islet cell hyperplasia and a case of neonatal nesidioblastosis. In addition, a tissue array (LandMark High Density Cancer Tissue MicroArray) comprising 280 various tumor and matched normal specimens was utilized. In PETs, the expression of pancreatic hormones, chromogranin-A, synaptophysin and Ki-67 were also evaluated. In the normal pancreas PNUTL1 expression is almost exclusively confined to the islet cells, weak expression was occasionally seen in some acinar cells, while immunoreactivity was completely absent in the ductal epithelia. PNUTL1 expression is maintained at similar high levels in hyperplastic and neoplastic islet cells, but this did not correlate with any of the clinicopathological data nor with proliferation status in PETs. Weak immunoreactivity was also noted in a proportion of exocrine neoplasms. Our findings describe for the first time the high expression levels of PNUTL1 in human pancreatic endocrine cells that suggests a similar role of this protein in islet cells to that demonstrated in neuronal tissues, and warrants further functional studies of this protein.
authors.affiliation: Digestive and Liver Disease Unit, II Medical School, University La Sapienza, Roma, Italy.
authors.forename: Gabriele
authors.initials: G
authors.lastname: Capurso
authors.forename: Tatjana
authors.initials: T
authors.lastname: Crnogorac-Jurcevic
authors.forename: Massimo
authors.initials: M
authors.lastname: Milione
authors.forename: Francesco
authors.initials: F
authors.lastname: Panzuto
authors.forename: Nicoletta
authors.initials: N
authors.lastname: Campanini
authors.forename: Sally E
authors.initials: SE
authors.lastname: Dowen
authors.forename: Alessia
authors.initials: A
authors.lastname: Di Florio
authors.forename: Claudio
authors.initials: C
authors.lastname: Sette
authors.forename: Cesare
authors.initials: C
authors.lastname: Bordi
authors.forename: Nicholas R
authors.initials: NR
authors.lastname: Lemoine
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Delle Fave
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015152:Blotting, Northern / Q000379:methods; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D005260:Female; D015870:Gene Expression / Q000502:physiology*; D015972:Gene Expression Regulation, Neoplastic / Q000502:physiology*; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D007223:Infant; D007515:Islets of Langerhans / Q000378:metabolism*; D018653:Juniperus / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D010190:Pancreatic Neoplasms / Q000378:metabolism*; D040081:Protein Array Analysis / Q000379:methods; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D058112:Septins
chemical_list: D018797:Cell Cycle Proteins; D012333:RNA, Messenger; C109366:SEPTIN5 protein, human; D058112:Septins