Nordihydroguaiaretic acid-induced Ca2+ handling and cytotoxicity in human prostate cancer cells.

Abstract

The effect of nordihydroguaiaretic acid (NDGA), a compound commonly used as a lipoxygenases inhibitor, on intracellular free Ca2+ levels ([Ca2+]i) in PC3 human prostate cancer cells was investigated. [Ca2+]i was measured by using the Ca2+ -sensitive dye fura-2. NDGA increased [Ca2+]i in a concentration-dependent manner with an EC50 of 30 microM. The Ca2+ signal comprised a gradual and sustained increase. Removal of extracellular Ca2+ partly decreased the NDGA-induced [Ca2+]i increase, suggesting that the Ca2+ signal was due to both extracellular Ca2+ influx and intracellular Ca2+ release. NDGA-induced Ca2+ influx was independently confirmed by measuring NDGA-induced Mn2+ -coupled quench of fura-2 fluorescence. The NDGA-induced Ca2+ influx was not affected by L-type Ca2+ channel blockers. In Ca2+ -free medium, the NDGA-induced [Ca2+]i increase was abolished by pretreatment with 1 microM thapsigargin (an endoplasmic reticulum Ca2+ pump inhibitor), and conversely, pretreatment with NDGA abolished thapsigargin-induced [Ca2+]i increase. NDGA-induced intracellular Ca2+ release was not altered by inhibition of phospholipase C. Overnight treatment with 20-50 microM NDGA inhibited cell proliferation rate in a concentration-dependent manner. Several other lipoxygenases inhibitors did not alter [Ca2+]i. Collectively, this study shows that in prostate cells, NDGA induced a [Ca2+]i increase via releasing stored Ca2+ from the endoplasmic reticulum in a manner independent of phospholipase C activity, and by causing Ca2+ influx. NDGA also caused cytotoxicity at higher concentrations.

• Authors: Jong-Khing Huang, Wei-Chuan Chen, Chun-Jen Huang, Shu-Shong Hsu, Jin-Shyr Chen, He-Hsiung Cheng, Hong-Tai Chang, Bang-Ping Jiann, Chung-Ren Jan
• Journal: Life sciences (Life Sci) Vol. 75 Issue 19 Pg. 2341-51 (Sep 24 2004) ISSN: 0024-3205 [Print] Netherlands
• PMID: 15350831 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Antineoplastic Agents
• Calcium Channel Blockers
• Calcium Channels, L-Type
• Fluorescent Dyes
• Lipoxygenase Inhibitors
• Solutions
• Masoprocol
• Type C Phospholipases
• Calcium
• Fura-2

Topics

• Antineoplastic Agents
• Calcium (metabolism)
• Calcium Channel Blockers (pharmacology)
• Calcium Channels, L-Type (drug effects)
• Cell Division (drug effects)
• Cell Line, Tumor
• Cell Survival (drug effects)
• Colorimetry
• Fluorescent Dyes
• Fura-2
• Humans
• Lipoxygenase Inhibitors (pharmacology)
• Male
• Masoprocol (pharmacology)
• Prostatic Neoplasms (drug therapy, metabolism)
• Solutions
• Type C Phospholipases (metabolism)