title: Expression of peptidyl-prolyl isomerase PIN1 and its role in the pathogenesis of extrahepatic cholangiocarcinoma.
abstract: The phosphorylation of proteins on serine/threonine residues that immediately precede proline (pSer/Thr-Pro) is a key signaling mechanism by which cell cycle regulation and cell differentiation and proliferation occur. The peptidyl-prolyl isomerase PIN1-catalyzed conformational changes of the pSer/Thr-Pro motifs may have profound effects on the function of numerous oncogenic and cell signaling pathways. To date, no studies have examined the expression of PIN1 and its potential role in the pathogenesis of extrahepatic cholangiocarcinoma (ECC). Therefore, the present study performed an immunohistochemistry analysis of the expression of PIN1 in 67 cases of ECC and evaluated its association with clinicopathological factors. In addition, the role of PIN1 was examined using synthetic small interfering RNA (siRNA) to silence PIN1 gene expression in human CC RBE cells. Positive PIN1 expression was observed in 35 of the 67 (52.2%) ECC cases and was predominantly localized to the nucleus of the tumor cells. The immunoreactive score for PIN1 was significantly higher in the tumor cells (4.07±0.4) compared with the adjacent benign bile duct cells (1.19±0.4) (P<0.001). PIN1 expression was significantly correlated with tumor cell proliferation (Ki-67 labeling index; P=0.024). Silencing PIN1 expression using siRNA significantly decreased the proliferation, migration and invasion of the tumor cells. In conclusion, the results indicated that the expression of PIN1 may play a key role in the development and progression of ECC.
authors.affiliation: Department of Pathology, Chonbuk National University, Medical School, Research Institute of Clinical Medicine and Research Institute for Endocrine Sciences, Jeonju, Chonbuk 561-756, South Korea.
authors.forename: Urangoo
authors.initials: U
authors.lastname: Jamiyandorj
authors.forename: Jun Sang
authors.initials: JS
authors.lastname: Bae
authors.forename: Sang Jae
authors.initials: SJ
authors.lastname: Noh
authors.forename: Sarangerel
authors.initials: S
authors.lastname: Jachin
authors.forename: Ji Eun
authors.initials: JE
authors.lastname: Choi
authors.forename: Kyu Yun
authors.initials: KY
authors.lastname: Jang
authors.forename: Myoung Ja
authors.initials: MJ
authors.lastname: Chung
authors.forename: Myoung Jae
authors.initials: MJ
authors.lastname: Kang
authors.forename: Dong Geun
authors.initials: DG
authors.lastname: Lee
authors.forename: Woo Sung
authors.initials: WS
authors.lastname: Moon
keywords: extrahepatic cholangiocarcinoma; peptidyl-prolyl isomerase PIN1; phosphorylation