Enhancement of esculetin on Taxol-induced apoptosis in human hepatoma HepG2 cells.
The potential use of low dose chemotherapy has been appealing since lower dosages are more attainable during cancer therapy and cause less toxicity in patients. Combination therapy of Taxol, a promising frontline chemotherapy agent, with natural anti-tumor agents that are considerably less toxic with a capability of activating additional apoptotic signals or inhibiting survival signals may provide a rational molecular basis for novel chemotherapeutic strategies. Esculetin, a well-known lipoxygenase inhibitor, showed an inhibitory effect on the cell cycle progression of HL-60 cells in our previous study. In this report, the effects of a concomitant administration of esculetin and Taxol were investigated in human hepatoma HepG2 cells. Firstly, esculetin alone could exert an antiproliferation effect together with an inhibitory effect on the activation of ERKs and p38 MAPK. As compared to the treatment with Taxol only, a co-administration with esculetin and Taxol could result in a further enhancement of apoptosis as revealed by DNA fragmentation assay and Annexin-V-based assay. Meanwhile, immunoblotting analysis also showed that the co-administration of esculetin and Taxol could increase the expression of Bax and the cytosolic release of cytochrome C and enhance the expression of Fas and Fas ligand while the activation of caspase-8 and caspase-3 was also increased. Finally, the ERK cascade was proven to be involved in the enhancement of esculetin on the Taxol-induced apoptosis.
Kuo
Hsing-Chun
HC
Institute of Biochemistry and Biotechnology, Chung Shan Medical University, Chien Kuo N. Road, Taichung 402, Taiwan.
Lee
Herng-Jiun
HJ
Hu
Chao-Chin
CC
Shun
Han-I
HI
Tseng
Tsui-Hwa
TH
D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D020169:Caspases / Q000378:metabolism; D045744:Cell Line, Tumor; D045304:Cytochromes c / Q000378:metabolism; D004357:Drug Synergism; D004591:Electrophoresis, Polyacrylamide Gel; D053222:Fas Ligand Protein; D006801:Humans; D015151:Immunoblotting; D008562:Membrane Glycoproteins / Q000378:metabolism; D008856:Microscopy, Fluorescence; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D017239:Paclitaxel / Q000494:pharmacology*; D048069:Tumor Necrosis Factors / Q000378:metabolism; D014468:Umbelliferones / Q000494:pharmacology*; D051028:bcl-2-Associated X Protein / Q000378:metabolism
D000970:Antineoplastic Agents; C494826:BAX protein, human; C505661:FASLG protein, human; D053222:Fas Ligand Protein; D008562:Membrane Glycoproteins; D048069:Tumor Necrosis Factors; D014468:Umbelliferones; D051028:bcl-2-Associated X Protein; D045304:Cytochromes c; D020928:Mitogen-Activated Protein Kinases; D020169:Caspases; D017239:Paclitaxel; C007628:esculetin