The PKC delta inhibitor, rottlerin, induces apoptosis of haematopoietic cell lines through mitochondrial membrane depolarization and caspases' cascade.
Rottlerin is a widely selective protein kinase C delta (PKCdelta) inhibitor isolated from Mallotus philippinensis. It shown to be effective against several human tumor cell lines and in potentiating chemotherapy-induced cytotoxcicity. Using the trypan blue exclusion assay, we demonstrated that rottlerin reduced the viability in a dose- and time-dependent manner of human leukemia HL60 cells, human acute T cell leukemia Jurkat cells and mouse macrophage RAW 264.7 cells. Rottlerin caused apoptosis and the apaptotic processing was inhibited by a caspase inhibitor, z-VAD-fmk, in these haematopoietic cells. The apoptosis-inducing activities were determined by nuclear condensation, sub-G1 appearance, DNA fragmentation, loss of mitochondrial membrane potential (Deltapsim), release of mitochondrial cytochrome c into cytoplasm and proteolytic activation of caspase 9 and 3. Expression of PKCdelta and Bcl-2 protein inhibited Deltapsim change and repressed cell death. These studies suggest that the cytotoxic effects of rottlerin through inhibition of PKCdelta cause mitochondrial dysfunction, cytochrome c release from mitochondria into cytoplasm and the activation of caspases' cascade.
Liao
Ya-Fan
YF
Department of Life Sciences, National Chung-Hsing University, Taichung, Taiwan, ROC.
Hung
Ying-Cheng
YC
Chang
Wen-Huei
WH
Tsay
Gregory J
GJ
Hour
Tzyh-Chyuan
TC
Hung
Hui-Chih
HC
Liu
Guang-Yaw
GY
D000098:Acetophenones / Q000494:pharmacology*; D000818:Animals; D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D001578:Benzopyrans / Q000494:pharmacology*; D020169:Caspases / Q000378:metabolism* / Q000502:physiology; D045744:Cell Line, Tumor; D053938:DNA Fragmentation / Q000187:drug effects / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006412:Hematopoietic Stem Cells / Q000187:drug effects* / Q000201:enzymology; D006801:Humans; D007425:Intracellular Membranes / Q000187:drug effects* / Q000201:enzymology; D008564:Membrane Potentials; D051379:Mice; D008928:Mitochondria / Q000187:drug effects* / Q000201:enzymology; D011493:Protein Kinase C / Q000037:antagonists & inhibitors* / Q000502:physiology; D051745:Protein Kinase C-delta; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology
D000098:Acetophenones; D001578:Benzopyrans; D004791:Enzyme Inhibitors; C085746:rottlerin; C497259:Prkcd protein, mouse; C497258:PRKCD protein, human; D011493:Protein Kinase C; D051745:Protein Kinase C-delta; D020169:Caspases