Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0023418 (leukemia)
 93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Some chemotherapeutic agents, as well as TNF and Fas, induce apoptotic cell death in tumor cells, but the cellular components involved in the process have not yet been identified. Interleukin 1 beta converting enzyme (ICE) is a mammalian homolog of CED-3, a protein required for programmed cell death in nematode Caenorhabditis elegans. We found that a selective inhibitor of ICE/ced 3 family proteases, benzyloxycarbonyl Asp CH2OC(O) 2 6,-dichlorobenzene (Z-Asp-CH2-DCB). completely blocked the apoptotic cell death of human leukemia cells caused by etoposide, camptothecin, 1-beta-D-arabinofuranosyl cytosine (Ara-C) and adriamycin. Moreover, in antitumor agent-treated U937 cells, an ICE-like (CPP32-like) protease was strongly activated. These results indicate that ICE/ ced 3 family proteases are involved in antitumor agent-induced apoptosis. Activation of ICE family proteases plays a key role in apoptosis. However, the subsequent mechanisms resulting in apoptosis are largely unknown. We identified actin as a substrate of ICE family proteases. Cleavage of actin and other substrate proteins by ICE family proteases could be critical in the ongoing process of antitumor agent-induced apoptosis in tumor cells.
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PMID:[Involvement of ICE/CED 3 family proteases in antitumor agent-induced apoptosis]. 903 Feb 33

7-hydroxystaurosporine (UCN-01) is a more selective protein kinase C inhibitor than staurosporine. UCN-01 exhibits antitumor activity in experimental tumor models and is presently in clinical trials. Our study reveals that human myeloblastic leukemia HL60 and K562 and colon carcinoma HT29 cells undergo internucleosomal DNA fragmentation and morphological changes characteristic of apoptosis after UCN-01 treatment. These three cell lines lack functional p53, and K562 and HT29 cells are usually resistant to apoptosis. DNA fragmentation in HT29 and K562 cells occurred after 1 day of treatment while it took less than 4 h in HL60 cells. Cycloheximide prevented UCN-01-induced DNA fragmentation in HT-29 cells, but not in HL60 and K562 cells, suggesting that macromolecular synthesis is selectively required for apoptotic DNA fragmentation in HT29 cells. UCN-01-induced DNA fragmentation was preceded by activation of cyclin B1/cdc2 kinase. Further studies in HL60 cells showed that UCN-01-induced apoptosis was associated with degradation of CPP32, PARP, and lamin B and that the inhibitor of caspases (ICE/CED-3 cysteine proteases), Z-VAD-FMK, and the serine protease inhibitor, DCI, protected HL60 cells from UCN-01-induced DNA fragmentation. However, only DCI and TPCK, but not Z-VAD-FMK, inhibited DNA fragmentation in the HL60 cell-free system, suggesting that serine protease(s) may play a role in the execution phase of apoptosis in HL60 cells treated with UCN-01. Z-VAD-FMK and DCI also inhibited apoptosis in HT29 cells. These data demonstrate that the protein kinase C inhibitor and antitumor agent, UCN-01 is a potent apoptosis inducer in cell lines that are usually resistant to apoptosis and lack p53 and that caspases and probably serine proteases are activated during UCN-01-induced apoptosis.
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PMID:7-Hydroxystaurosporine (UCN-01) induces apoptosis in human colon carcinoma and leukemia cells independently of p53. 926 Sep 9

The human leukemia cell line, HL60 is very sensitive to various apoptotic stimuli and p53-null. The death-related cysteine proteases of the caspases family play a central role in the execution phase of apoptosis, and we recently reported the importance of serine protease activation in camptothecin-induced apoptotic endonuclease activation in HL60 cells. In the present study, we investigated the role of caspases (ICE/CED-3-related cysteine proteases) and serine proteases in cell death induced by the topoisomerase I inhibitor, camptothecin, in HL60 cells and in a cell-free system. We found that CPP32 is activated during camptothecin-induced apoptosis, and that N-benzyloxycarbony-Val-Ala-Asp (O-methyl) -fluoromethyketone (Z-VAD-fmk), a cell permeable caspase inhibitor blocks all features of apoptosis: morphological changes, cleavage of caspase 3 (CPP32/Yama/Apopain) and poly(ADP-ribose) polymerase, lamin B degradation and DNA fragmentation. However, Z-VAD-fmk and two other ICE/CED-3 inhibitors, YVAD-CHO and DEVD-CHO, were inactive in a cell-free system reconstituted from nuclei of untreated HL60 cells and cytosol from camptothecin-treated cells, suggesting that caspases are not required for endonuclease activation or lamin B cleavage in the cell-free system. By contrast, the serine protease inhibitors, 3,4-dichloroisocoumarin (DCI) and L-1-chloro-3-(4-tosylamido)-4-phenyl-2-butanone tosyl-L-phenylalanine chloromethyl ketone (TPCK), abolished the apoptosis-associated biochemical changes induced by camptothecin both in whole cells and in a cell-free system. DCI also inhibited CPP32 cleavage. Taken together, these results suggest that in HL60 cells, both CPP32 and serine proteases are activated in camptothecin-induced apoptosis.
Leukemia 1997 Aug
PMID:Camptothecin-induced apoptosis in p53-null human leukemia HL60 cells and their isolated nuclei: effects of the protease inhibitors Z-VAD-fmk and dichloroisocoumarin suggest an involvement of both caspases and serine proteases. 926 76

Intracellular cysteine proteases are important mediators of apoptosis. Indeed, some nuclear proteins and enzymes are cleaved during apoptosis, in particular poly(ADP-ribose) polymerase (PARP), which is activated by DNA strand interruptions and is involved in DNA repair. PARP is cleaved into two fragments of 29 and 85 kDa (apparent molecular mass) in human promyelomonocytic leukemia cells, HL-60, treated with etoposide to induce apoptosis. These cells possess protease activities, caspases, that share many features with the ICE/CED-3 family. The cleavage occurs between Asp-214 and Gly-215, a site that is conserved in human, bovine, and chicken PARP. This cleavage has been shown to be an early marker of apoptosis. To monitor apoptosis, to understand the role of PARP cleavage by caspases, and to study the role of the two fragments in DNA repair, members of our laboratory have developed two polyclonal antipeptide antibodies directed against the two human PARP sequences: [196-214] for LP96-22 and [215-228] for LP96-24. Moreover, these antibodies will be useful to map the necrotic cleavage of PARP, which generates fragments different from those obtained during apoptosis, and thus to discriminate between apoptotic and necrotic cell death.
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PMID:Characterization of antibodies specific for the caspase cleavage site on poly(ADP-ribose) polymerase: specific detection of apoptotic fragments and mapping of the necrotic fragments of poly(ADP-ribose) polymerase. 949 68

Bcl-2 family proteins and interleukin-1-beta converting enzyme/Caenorhabditis elegans cell death gene-3 (ICE/CED-3) family proteases (caspases) represent the basic regulators of apoptosis. However, the precise mechanism by which they interact is unclear. In this study, we found that gamma-radiation-induced apoptosis of leukemia cells was associated with activation of multiple caspases and bax up-regulation. Membrane changes and caspase activities were suppressed by specific caspase inhibitors. Similarly, the serine protease inhibitors z-Ala-Ala-Asp-cmk (AAD) and tosyl-lysine chloromethyl ketone (TLCK) also prevented caspase activation and poly(ADP-ribose) polymerase cleavage in vivo but had no effect on caspase activity in vitro. TLCK also prevented bax up-regulation as a result of its inhibitory effect on p53 function. Inhibitors of caspases and serine proteases partially prevented cell death, suggesting a caspase involvement in Bax-mediated cell death. We propose an ordering of signaling events in Bax-mediated cell death, including steps upstream and downstream of p53 and bax up-regulation.
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PMID:Ionizing radiation-induced, Bax-mediated cell death is dependent on activation of cysteine and serine proteases. 1043 17

The majority of ovarian follicles undergo atresia mediated by apoptosis. Bcl-2-related proteins act as regulators of apoptosis via the formation of dimers with proteins inside and outside the Bcl-2 family. Previous studies have identified BAD as a proapoptotic Bcl-2 family member expressed in the ovary. It is known that BAD phosphorylation induced by survival factors leads to its preferential binding to 14-3-3 and suppression of the death-inducing function of BAD. To identify ovarian binding partners for hypophosphorylated BAD, we performed a yeast two-hybrid screening of a rat ovary complementary DNA library using as bait a mutant BAD incapable of binding to 14-3-3. Screening of yeast transformants yielded positive clones encoding the rat ortholog of Mcl-1 (myeloid cell leukemia-1), an antiapoptotic Bcl-2 protein. Amino acid sequence analysis revealed that rat and human Mcl-1 showed a complete conservation of the Bcl-2 homology domains BH1, BH2, and BH3. In the yeast two-hybrid system, Mcl-1 binds to the hypophosphorylated mutant of BAD and interacts preferentially with different proapoptotic (Bax, Bak, Bok, Bik, and BOD) compared with antiapoptotic Bcl-2 family members (Bcl-2, Bcl-xL, Bcl-w, Bfl-1, CED-9, and BHRF-1). Northern blot hybridization demonstrated expression of Mcl-1 transcripts of 2.3 and 3.7 kb in the ovary and diverse other rat tissues. In immature rats, PMSG treatment led to a transient increase in the 2.3-kb Mcl-1 transcript, peaking at 6 h after injection and returning to baseline levels after 24 h. Moreover, the same transcript was induced in the PMSG-primed preovulatory rat ovary 6 h after the administration of ovulatory doses of either hCG or FSH. In situ hybridization studies revealed that the gonadotropin stimulation of ovarian Mcl-1 message occurs in both granulosa and thecal cells. In conclusion, rat Mcl-1 was identified as an ovarian BAD-interacting protein and the message for the antiapoptotic Mcl-1 protein was induced after treatment with gonadotropins in granulosa and thecal cells of growing follicles.
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PMID:Characterization of the antiapoptotic Bcl-2 family member myeloid cell leukemia-1 (Mcl-1) and the stimulation of its message by gonadotropins in the rat ovary. 1057 8

Crk family adaptors are widely expressed and mediate the timely formation of signal transduction protein complexes upon a variety of extracellular stimuli, including various growth and differentiation factors. Selective formation of multi-protein complexes by the Crk and Crk-like (CRKL) proteins depends on specific motifs recognized by their SH2 and SH3 domains. In the case of the first SH3 domains [SH3(1)] a P-x-x-P-x-K motif is crucial for highly selective binding, while the SH2 domains prefer motifs which conform to the consensus pY-x-x-P. Crk family proteins are involved in the relocalization and activation of several different effector proteins which include guanine nucleotide releasing proteins like C3G, protein kinases of the Abl- and GCK-families and small GTPases like Rap1 and Rac. Crk-type proteins have been found not only in vertebrates but also in flies and nematodes. Major insight into the function of Crk within organisms came from the genetic model organism C. elegans, where the Crk-homologue CED-2 regulates cell engulfment and phagocytosis. Other biological outcomes of the Crk-activated signal transduction cascades include the modulation of cell adhesion, cell migration and immune cell responses. Crk family adaptors also appear to play a role in mediating the action of human oncogenes like the leukaemia-inducing Bcr-Abl protein. This review summarizes some key findings and highlights recent insights and open questions.
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PMID:Crk family adaptors-signalling complex formation and biological roles. 1160 38