Involvement of Kv1.1 and Nav1.5 in proliferation of gastric epithelial cells

✍ Scribed by William Ka Kei Wu; Gui Rong Li; Helen Pui Shan Wong; Marco King Cheung Hui; Emily Kin Ki Tai; Emily Kai Yee Lam; Vivian Yvonne Shin; Yi Ni Ye; Peng Li; Ying Hua Yang; Jiing Chyuan Luo; Chi Hin Cho

• Publisher: John Wiley and Sons
• Year: 2006
• Tongue: English
• Weight: 295 KB
• Volume: 207
• Category: Article
• ISSN: 0021-9541
• DOI: 10.1002/jcp.20576

✦ Synopsis

Abstract

In the present study, patch clamp experiments demonstrated the expression of multiple ionic currents, including a Ba^2+^‐sensitive inward rectifier K^+^ current (I~Kir~), a 4‐aminopyridine‐ (4‐AP) sensitive delayed rectifier K^+^ current (IK~DR~), and a nifedipine‐sensitive, tetrodotoxin‐resistant inward Na^+^ current (I~Na.TTXR~) in the non‐transformed rat gastric epithelial cell line RGM‐1. RT‐PCR revealed molecular identities of mRNAs for the functional ionic currents, including K~ir~1.2 for I~Kir~, K~v~1.1, K~v~1.6, and K~v~2.1 for IK~DR~, and Na~v~1.5 for I~Na.TTXR~. Pharmacologic blockade of K~v~ and Na~v~, but not K~ir~, suppressed RGM‐1 cell proliferation. To further elucidate which subtypes of the ion channels were involved in cell proliferation, RNA interference was employed to knockdown specific gene expression. Downregulation of K~v~1.1 or Na~v~1.5 by RNA interference suppressed RGM‐1 cell proliferation. To conclude, our study is the first to delineate the expression of ion channels and their functions as growth modulators in gastric epithelial cells. J. Cell. Physiol. 207: 437–444, 2006. © 2005 Wiley‐Liss, Inc.