Exp Mol Med.  2006 Oct;38(5):535-545.

Doxorubicin-induced reactive oxygen species generation and intracellular Ca2+increase are reciprocally modulated in rat cardiomyocytes

• Kim SY
• Kim SJ
• Kim BJ
• Rah SY
• Chung SM
• Im MJ
• Kim UH

Abstract

Doxorubicin (DOX) is one of the most potent anticancer drugs and induces acute cardiac arrhythmias and chronic cumulative cardiomyopathy. Though DOX-induced cardiotoxicity is known to be caused mainly by ROS generation, a disturbance of Ca2+ homeostasis is also implicated one of the cardiotoxic mechanisms. In this study, a molecular basis of DOX-induced modulation of intracellular Ca2+ concentration ([Ca2+]i) was investigated. Treatment of adult rat cardiomyocytes with DOX increased [Ca2+]i irrespectively of extracellular Ca2+, indicating DOX-mediated Ca2+ release from intracellular Ca2+ stores. The DOX-induced Ca2+ increase was slowly processed and sustained. The Ca2+ increase was inhibited by pretreatment with a sarcoplasmic reticulum (SR) Ca2+ channel blocker, ryanodine or dantrolene, and an antioxidant, alpha-lipoic acid or alpha-tocopherol. DOX-induced ROS generation was observed immediately after DOX treatment and increased in a time-dependent manner. The ROS production was significantly reduced by the pretreatment of the SR Ca2+ channel blockers and the antioxidants. Moreover, DOX-mediated activation of caspase-3 was significantly inhibited by the Ca2+ channel blockers and a-lipoic acid but not a-tocopherol. In addition, cotreatment of ryanodine with alpha-lipoic acid resulted in further inhibition of the casapse-3 activity. These results demonstrate that DOX-mediated ROS opens ryanodine receptor, resulting in an increase in [Ca2+]i and that the increased [Ca2+]i induces ROS production. These observations also suggest that DOX/ROS-induced increase of [Ca2+]i plays a critical role in damage of cardiomyocytes.

Keyword

apoptosis; calcium signaling; doxorubicin; myocytes, cardiac; reactive oxygen species

MeSH Terms

Sarcoplasmic Reticulum/drug effects
Ryanodine Receptor Calcium Release Channel/metabolism
Reactive Oxygen Species/*chemical synthesis
Rats, Sprague-Dawley
Rats
Myocytes, Cardiac/*drug effects
Male
Female
Enzyme Activation/drug effects
Doxorubicin/*pharmacology
Cells, Cultured
Caspase 3/metabolism
Calcium Channel Blockers/pharmacology
Calcium/*metabolism
Antioxidants/pharmacology
Antibiotics, Antineoplastic/pharmacology
Animals