Involvement of reactive oxygen species/c-Jun NH(2)-terminal kinase pathway in kotomolide A induces apoptosis in human breast cancer cells.

Abstract

The anticancer effects of kotomolide A (KTA), a new butanolide constituent isolated from the leaves of Cinnamomum kotoense (Lauraceae), on the two human breast cancer cell lines MCF-7 and MDA-MB-231, were first investigated in our study. KTA exhibited selectively antiproliferative effects in cancer cell lines without showing any toxicity in normal mammary epithelial cells. Treatment of cancer cells with KTA to trigger G2/M phase arrest was associated with increased p21/WAF1 levels and reduced amounts of cyclin A, cyclin B1, cdc2 and cdc25C. KTA induced cancer cell death treatment by triggering mitochondrial and death receptor 5 (DR5) apoptotic pathways, but did not act on the Fas receptor. Exposure of MCF-7 and MDA-MB-231 cells to KTA resulted in cellular glutathione reduction and ROS generation, accompanied by JNK activation and apoptosis. Both antioxidants, NAC and catalase, significantly decreased apoptosis by inhibiting the phosphorylation of JNK and subsequently triggering DR5 cell death pathways. The reduction of JNK expression by siRNA decreased KTA-mediated Bim cleavage, DR5 upregulation and apoptosis. Furthermore, daily KTA i.p. injections in nude mice with MDA-MB-231 s.c. tumors resulted in a 50% decrease of mean tumor volume, compared with vehicle-treated controls. Taken together, the data show that cell death of breast cancer cells in response to KTA is dependent upon ROS generation and JNK activation, triggering intrinsic and extrinsic apoptotic pathways. The ROS/JNK pathway could be a useful target for novel approaches in breast cancer chemotherapy.

• Authors: Po-Lin Kuo, Chung-Yi Chen, Tz-Fei Tzeng, Chun-Ching Lin, Ya-Ling Hsu
• Journal: Toxicology and applied pharmacology (Toxicol Appl Pharmacol) Vol. 229 Issue 2 Pg. 215-26 (Jun 01 2008) ISSN: 0041-008X [Print] United States
• PMID: 18374381 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Reactive Oxygen Species
• kotomolide A
• JNK Mitogen-Activated Protein Kinases
• 4-Butyrolactone

Topics

• 4-Butyrolactone (analogs & derivatives, pharmacology)
• Animals
• Apoptosis (drug effects)
• Breast Neoplasms (enzymology, metabolism, pathology)
• Cell Cycle (drug effects)
• Cell Line, Tumor
• Cell Proliferation (drug effects)
• Enzyme Activation
• Female
• Humans
• JNK Mitogen-Activated Protein Kinases (metabolism)
• Mice
• Mice, Inbred BALB C
• Mice, Nude
• Reactive Oxygen Species (metabolism)
• Stereoisomerism