Basic Research
Copyright ©2008 The WJG Press and Baishideng. All rights reserved.
World J Gastroenterol. Jul 28, 2008; 14(28): 4473-4479
Published online Jul 28, 2008. doi: 10.3748/wjg.14.4473
Lysophosphatidic acid induced nuclear translocation of nuclear factor-κB in Panc-1 cells by mobilizing cytosolic free calcium
Yoshiyuki Arita, Tetsuhide Ito, Takamasa Oono, Ken Kawabe, Terumasa Hisano, Ryoichi Takayanagi
Yoshiyuki Arita, Tetsuhide Ito, Takamasa Oono, Ken Kawabe, Terumasa Hisano, Ryoichi Takayanagi, Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan
Author contributions: Arita Y and Ito T designed research; Arita Y, Oono T, Kawabe K, and Hisano T performed research; Arita Y, Ito T, and Takayanagi R analyzed data; Arita Y and Ito T wrote the paper.
Correspondence to: Tetsuhide Ito, MD, PhD, Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan. itopapa@intmed3.med.kyushu-u.ac.jp
Telephone: +81-92-6425285
Fax: +81-92-6425287
Received: February 20, 2008
Revised: July 14, 2008
Accepted: July 21, 2008
Published online: July 28, 2008
Abstract

AIM: To clarify whether Lysophosphatidic acid (LPA) activates the nuclear translocation of nuclear factor-κB (NF-κB) in pancreatic cancer.

METHODS: Panc-1, a human pancreatic cancer cell line, was used throughout the study. The expression of LPA receptors was confirmed by reverse-transcript polymerase chain reaction (RT-PCR). Cytosolic free calcium was measured by fluorescent calcium indicator fura-2, and the localization of NF-κB was visualized by immunofluorescent method with or without various agents, which effect cell signaling.

RESULTS: Panc-1 expressed LPA receptors, LPA1, LPA2 and LPA3. LPA caused the elevation of cytosolic free calcium dose-dependently. LPA also caused the nuclear translocation of NF-κB. Cytosolic free calcium was attenuated by pertussis toxin (PTX) and U73122, an inhibitor of phospholipase C. The translocation of NF-κB was similarly attenuated by PTX and U73122, but phorbol ester, an activator of protein kinase C, alone did not translocate NF-κB. Furthermore, the translocation of NF-κB was completely blocked by Ca2+ chelator BAPTA-AM. Thapsigargin, an endoplasmic-reticulum Ca2+-ATPase pump inhibitor, also promoted the translocation of NF-κB. Staurosporine, a protein kinase C inhibitor, attenuated translocation of NF-κB induced by LPA.

CONCLUSION: These findings suggest that protein kinase C is activated endogenously in Panc-1, and protein kinase C is essential for activating NF-κB with cytosolic calcium and that LPA induces the nuclear translocation of NF-κB in Panc-1 by mobilizing cytosolic free calcium.

Keywords: Lysophosphatidic acid; Nuclear translocation; Nuclear factor-κB; Cytosolic free calcium; Panc-1