Norcantharidin preferentially induces apoptosis in human leukemic Jurkat cells without affecting viability of normal blood mononuclear cells.
Norcantharidin (NCTD) is known to have anti-cancer potentials. The aim of this study was to assess the apoptosis-inducing effect of NCTD on human leukemic Jurkat cells. We found that NCTD preferentially inhibited the growth of Jurkat cells in a dose- and time-dependent manner, but not the growth of normal blood mononuclear cells (MNC). Pretreatment with agonistic (CH-11) and antagonistic (ZB4) Fas antibodies on Jurkat cells showed that NCTD-induced apoptosis might not involve Fas-FasL signaling. Flow cytometric assay of Jurkat cells treated with NCTD showed a markedly increased sub-G1 DNA phase and cell cycle arrest at S phase. Western blot analysis of NCTD-treated cells showed increased expressions of cytochrome c, active caspase-9 and -3, and cleavage of poly(ADP-ribose) polymerase (PARP), but the expressions of Bcl-2, Bax and apoptosis-inducing factor were not increased. The transcription factor STAT1 was translocated from cytosol to nucleus. Pancaspase inhibitor z-VAD-FMK not only limited the level of sub-G1 phase, but also prevented the degradation of PARP in NCTD-treated cells. The NCTD-induced cell cycle arrest and apoptosis were mediated through the regulation of ataxia-telangiectasia mutated (ATM), rather than P63 protein. The conditioned medium produced from human MNC (NCTD-MNC-CM) increased the percentage of apoptotic cells and the expression of PARP cleavage in Jurkat cells. Protein array assay of NCTD-MNC-CM showed 32.4- and 6.2-folds increases in TNF-alpha and GM-CSF, respectively, and the expression of MCP-1, GRO, RANTES and IL-10 was decreased. We conclude that NCTD can induce apoptosis in human leukemic Jurkat cells via a caspase-dependent pathway without affecting the viability of normal MNC, and that the apoptosis-inducing effect of NCTD can also be achieved by soluble cytokines produced from peripheral MNC.
Liao
Hui-Fen
HF
Laboratory of Biophysics, Department of Research and Education, Taipei Veterans General Hospital, Taipei 112, Taiwan.
Su
Shu-Li
SL
Chen
Yu-Jen
YJ
Chou
Chin-Hung
CH
Kuo
Cheng-Deng
CD
D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000494:pharmacology*; D020169:Caspases / Q000378:metabolism; D049109:Cell Proliferation; D002470:Cell Survival / Q000187:drug effects; D016207:Cytokines / Q000096:biosynthesis; D004247:DNA / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005434:Flow Cytometry; D006801:Humans; D019169:Jurkat Cells / Q000187:drug effects*; D007963:Leukocytes, Mononuclear / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D020935:MAP Kinase Signaling System / Q000187:drug effects; D016196:S Phase / Q000187:drug effects*; D013997:Time Factors
D000970:Antineoplastic Agents; D019086:Bridged Bicyclo Compounds, Heterocyclic; D016207:Cytokines; C069741:norcantharidin; D004247:DNA; D020169:Caspases