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)

Glucosinolates (GL) can inhibit, retard or reverse experimental multistage carcinogenesis. When brassica plant tissue is broken, GLs are hydrolyzed by the endogenous enzyme myrosinase (Myr), releasing many products including isothiocyanates (ITC). Synthetic ITCs like sulforaphane exert chemopreventive effects against chemically induced tumors in animals, modulating enzymes required for carcinogens' activation/detoxification and/or the induction of cell-cycle arrest and apoptosis in tumor cell lines. To investigate the chemopreventive potential of ITCs while reproducing the circumstances of dietary contact with sulforaphane, we studied proliferation, apoptosis induction and p53, bcl-2 and bax protein expression in Jurkat T-leukemia cells by sulforaphane, the ITC generated in situ in a quantitative manner by Myr starting from glucoraphanin (GRA). Jurkat cells were treated with different doses of GRA-Myr mixture. Effects on cell growth or survival were evaluated by counting trypan blue-excluding cells. Cell-cycle progression, apoptosis and expression of p53, bax and bcl-2 proteins were analyzed by flow cytometry. Results were analyzed by two-sided Fisher's exact test. Sulforaphane, but not GRA, caused G(2)/M-phase arrest (P = 0.028) and increase of apoptotic cell fraction (P < 0.0001) in a time- and dose-dependent manner. Necrosis was observed after prolonged exposure to elevated sulforaphane doses. Moreover, it markedly increased p53 and bax protein expression, and slightly affected bcl-2 expression. These findings indicate that sulforaphane but not the native GL GRA can exert both protective and toxic effects inhibiting leukemic cell growth. Sulforaphane therefore deserves study as a potential chemopreventive/chemotherapeutic antileukemic agent.
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PMID:Growth inhibition, cell-cycle arrest and apoptosis in human T-cell leukemia by the isothiocyanate sulforaphane. 1196 Sep 9

It is well known that hyperthermia causes a transient tolerance of cells to a second heat challenge (acquired thermotolerance). The present study addresses the question of whether hyperthermic pre-treatment also increases the tolerance against heat- and hydrogen peroxide-induced apoptosis in rat IPC-81 leukaemia cells. This cell line exhibits an aberrant heat shock response which is characterized by a lack of the inducible Hsp70 isoform, even under conditions of heat or hydrogen peroxide stress, while the constitutively expressed Hsc70 and the inducible isoform of hemoxygenase (HO-1) are strongly enhanced by heat stress (43.5 degrees C; 30 min). In spite of this Hsp70 deficiency, hyperthermic pre-treatment protects IPC-81 leukaemia cells against apoptotic cell death induced by heat or hydrogen peroxide, but is less effective against necrosis induced by higher doses of the applied stressors. Addition of hydrogen peroxide (25 microM) enhances the amount of bax mRNA, while the level of bcl-2 mRNA remains unchanged. No increase of bax mRNA, in contrast, could be detected in heat shock-primed IPC-81 cells when treated with hydrogen peroxide after a 12h recovery. These results indicate that hyperthermic pre-treatment may exert its anti-apoptotic function not only by enhanced expression of constitutive as well as inducible HSPs but also by lowering the level of bax transcripts and thereby increasing the Bcl-2/Bax ratio.
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PMID:Hyperthermic pre-treatment protects rat IPC-81 leukaemia cells against heat- and hydrogen peroxide-induced apoptosis. 1207 89

We have studied the effect of N-(4-hydroxyphenyl)retinamide on either malignant human leukaemia cells or normal cells and investigated its mechanism of action. We demonstrate that 4HPR induces reactive oxygen species increase on mitochondria at a target between mitochondrial respiratory chain complex I and II. Such oxidative stress causes cardiolipin peroxidation which in turn allows cytochrome c release to cytosol, caspase-3 activation and therefore apoptotic consumption. Moreover, this apoptotic pathway seems to be bcl-2/bax independent and count only on malignant cells but not normal nor activated lymphocytes.
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PMID:Implication of mitochondria-derived ROS and cardiolipin peroxidation in N-(4-hydroxyphenyl)retinamide-induced apoptosis. 1208 92

Basic studies of oncogenesis have demonstrated that either the elevated production of particular oncogene proteins or the occurrence of qualitative abnormalities in oncogenes can contribute to neoplastic cellular transformation. The purpose of this study was to identify unique oncogenes that are differentially expressed in human cancers and characterize their functions in tumorigenesis. To discover new putative oncogenes, the differential display RT-PCR method was applied using normal cervical tissues, cervical cancer cell lines, cervical cancer tissues, and metastatic tissues. We identified a new human cervical cancer oncogene HCCR-2 that was overexpressed in various human tumors including leukemia, lymphoma, and carcinomas of the breast, kidney, ovary, stomach, colon, and uterine cervix. Ectopic expression of HCCR-2 resulted in direct tumorigenic conversions of NIH/3T3 and Rat1 fibroblasts. Nude mice injected with NIH/3T3 cells stably transfected with HCCR-2 formed tumors in 4 weeks. The resultant tumors display characteristics of an epithelial carcinoma. In HCCR-2 transfected NCI-H460 cells and RKO cells, stabilization of the p53 tumor suppressor occurred without genetic mutation and correlated with functional impairment, as indicated by the defective induction of p53-induced p21(WAF1), MDM2, and bax. These results indicate that HCCR-2 probably represents a new oncogene that is related to tumorigenesis, functioning as a negative regulator of the p53 tumor suppressor.
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PMID:Identification and differential expression of novel human cervical cancer oncogene HCCR-2 in human cancers and its involvement in p53 stabilization. 1287 13

The anti-leukemia activity of the saponin rich Gleditsia sinensis Lam. fruit extract (GSE) was investigated on cancer cell lines and bone marrow cells obtained from consented patients with chronic myelogenous leukemia (CML) and acute myelogenous leukemia (AML) during presentation. The growth inhibitory activity of the extract was determined by [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium] (MTS) assay. Colony formation assay was performed to investigate the regeneration potential. Cellular morphology change was studied. Apoptosis was demonstrated by DNA electrophoresis, reverse transcription polymerase chain reaction (RT-PCR) and flow cytometry. The mean concentration to inhibit the cell growth by 50% (MTS50) was 18+/-1.6 micro g/ml for K562 CML cell line and 12+/-1.3 micro g/ml for HL-60 acute promyelocytic leukemia cell line. Patient samples showed a mean MTS50 of 13-28 micro g/ml. Non-malignant hematological disorder bone marrow samples showed a mean MTS50 from 45 to 53 micro g/ml. Loss of regeneration property after treatment with GSE of these two cancer cell lines were confirmed by colony formation assay. GSE was able to induce cell shrinkage in K-562. DNA laddering was observed by incubating the leukemia cells with GSE. RT-PCR demonstrated that the pro-apoptic gene bax was induced while the anti-apoptic gene bcl-2 and cell cycle active gene PCNA were reduced. Flow cytometric analysis showed that the apoptotic effect of GSE on leukemia cell line was time- and dose-dependent. Thus GSE might be potentially used as a chemotherapeutic drug to treat patients with acute and chronic myelogenous leukemia.
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PMID:Gleditsia sinensis fruit extract is a potential chemotherapeutic agent in chronic and acute myelogenous leukemia. 1288 47

We investigated proliferation and apoptosis induction in Jurkat T-leukemia cells by the new isothiocyanate 4-(methylthio)butylisothiocyanate (MTBITC). To help elucidate whether the effects of MTBITC are specific for cancer cells, we tested MTBITC on freshly isolated, non-transformed human peripheral T lymphocytes. The effects of MTBITC are leukemic-cell-specific and consist of derangements in a critical point of cell-cycle control (G2/M transition). In fact, an increase in the proportion of G2 cells (from about 18% to 50%) was apparent following 24 h of treatment, associated with a decrease in the protein expression of cyclin B1. The expression of cyclin-dependent kinase (CDK) 1 was more mildly attenuated by MTBITC. Our results demonstrated that high concentrations of MTBITC can also induce apoptosis, through an increase of p53 and bax, but not bcl-2, protein expression. No effects of MTBITC were demonstrated on non-transformed T lymphocytes. Taking into account its in vitro antineoplastic activity and selectivity toward leukemia cells, MTBITC can be viewed as a conceptually promising agent in cancer therapy.
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PMID:The new isothiocyanate 4-(methylthio)butylisothiocyanate selectively affects cell-cycle progression and apoptosis induction of human leukemia cells. 1473 60

Isothiocyanates exert chemopreventive effects against chemically induced tumors in animals, modulating enzymes required for carcinogens' activation/detoxification and/or the induction of cell-cycle arrest and apoptosis in tumor cell lines. To investigate the chemopreventive potential of isothiocyanates, we studied proliferation, apoptosis induction and p53, bcl-2 and bax protein expression in Jurkat T-leukemia cells by the isothiocyanate sulforaphane. Sulforaphane caused G(2)/M-phase delay and increase of apoptotic cell fraction in a time- and dose-dependent manner. Necrosis was observed after prolonged exposure to elevated sulforaphane doses. Moreover, it markedly increased p53 and bax protein expression, and slightly affected bcl-2 expression. Since selective targeting and low toxicity for normal host tissues are fundamental requisites for proposed chemopreventive agents such as sulforaphane, we tested sulforaphane on non-transformed phytohemagglutinin-stimulated human T-lymphocytes. We demonstrated that sulforaphane arrested cell-cycle progression in G1 phase by a significant down-modulation of cyclin D3. Moreover, sulforaphane induced apoptosis (and also necrosis), mediated by an increase in the expression of p53, whereas it exerted little effect on bcl-2 and bax levels. These findings indicate that sulforaphane can exert protective effects inhibiting leukemic cell growth. Moreover, sulforaphane is active not only in transformed lymphocytes but also in their normal counterpart. Although in vitro studies do not necessarily predict in vivo outcomes, our findings raise important questions regarding the suitability of sulforaphane for cancer chemoprevention.
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PMID:Sulforaphane modulates cell cycle and apoptosis in transformed and non-transformed human T lymphocytes. 1503 59

Transcriptional activation of AP-1 is intricately involved in cell proliferation and transformation. The natural product, nordihydroguaiaretic acid (NDGA) shows an inhibitory effect on the binding of jun/AP-1 protein to the AP-1 site in 12-O-tetradecanoylphorbol-13-acetate (TPA)-stimulated HL60 cells. The NDGA inhibits the auto-regulated de novo synthesis of c-jun mRNA in TPA-stimulated HL60 cells. Our data also determine that this compound induces proliferation inhibition and apoptosis in human leukemia HL60 cells. To obtain information on the functional role of the AP-1 inhibition by NDGA in apoptosis signaling, the effects of pharmacological inhibition of AP-1 binding on c-myc, p53, and bax protein level were determined. Our results indicate that treatment of cells with NDGA enhances c-myc, p53, and bax protein levels. To rule out the possibility that NDGA will induce apoptosis because of the effects on proteins other than AP-1, we investigated the effect of another AP-1 inhibitor, SP600125, which is specific to Jun-N-terminal kinase. SP600125 decreased not only the phosphorylation level of jun protein but also AP-1/DNA binding activity. Also, apoptosis was observed to be induced by SP600125, concomitant with the increase in c-myc, p53, and bax protein level. In addition, apoptosis induced by both AP-1 inhibitors was accompanied by the activation of a downstream apoptotic cascade such as caspase 9, caspase 3, and poly[ADP-ribose]polymerase (PARP). When the cells were treated with NDGA or SP600125 in the presence of antisense c-myc oligonucleotides, apoptosis was not observed and an increase of c-myc, p53, and bax proteins was not manifested. All these results show that the inhibition of the transcription factor AP-1 action is related with either the drug-induced apoptosis or the drug toxicity of the HL60 cells. The apoptosis induced by AP-1 inhibition may be dependent on c-myc protein levels suggesting that the c-myc protein induces apoptosis at a low level of AP-1 binding activity. Altogether, our findings suggest that the presence of the AP-1 signal acts as a survival factor that determines the outcome of myc-induced proliferation or apoptosis.
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PMID:Inhibition of AP-1 transcription activator induces myc-dependent apoptosis in HL60 cells. 1503 32

The Eastern Cooperative Oncology Group (ECOG) performed a phase 2 study in B-cell chronic lymphocytic leukemia (CLL) of oral theophylline, a methylxanthine that inhibits cyclic nucleotide phosphodiesterases, thereby inducing the intracellular accumulation of cyclic adenosine monophosphate (cAMP). In 25 patients with Rai stages 0-I, theophylline, 200 mg given orally every 12 h was well tolerated. There was one complete response after 22.5 months of treatment, which continues at 27+ months, and 18 other patients had stable disease. In vitro exposure of patients' lymphocytes to aminophylline (75-250 microg/ml), the soluble form of theophylline, resulted in dose- and time-dependent induction of apoptosis in 9/20 patients studied. Apoptosis was documented flow-cytometrically by monitoring the expression of bcl-2 and bax, forward light scatter, fluorescence intensity of binding of CD45 antibody, and the binding of annexin. Patients whose leukemic lymphocytes were susceptible to apoptosis induction by aminophylline in vitro experienced a significantly longer progression-free survival than patients whose cells were resistant to the drug in culture (P=0.025). This suggests that in a CLL population treated with theophylline, induction of an apoptotic response to the drug in vitro is prognostic for absence of clinical progression.
Leukemia 2004 Oct
PMID:Phase II study of theophylline in chronic lymphocytic leukemia: a study of the Eastern Cooperative Oncology Group (E4998). 1535 46

As with other candidate chemopreventive agents, most of our knowledge on the biological effects of isothiocyanates (the many sulfur-containing metabolites found in cruciferous vegetables) comes from studies of single natural or synthetic compounds. To investigate whether the biological/chemopreventive effects of administration of single isothiocyanates can differ from those of a mixture of isothiocyanates, we tested the effects of a mixture of four different isothiocyanates on cell-cycle progression and apoptosis in human T leukemia Jurkat cells, and identified some of the molecular pathways triggered by the mixture. The mixture affected critical points of the cell cycle via modulation of the expression of cyclin B1. Moreover, it induced apoptosis, mediated by an increase in p53 and bax (expression of bcl-2 was unaffected). Comparison of the data with those previously obtained with the single isothiocyanates under identical experimental conditions provides evidence that the quantitative effects of a single, specific isothiocyanate can be significantly different from those of an isothiocyanate mixture at realistic doses.
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PMID:A mixture of isothiocyanates induces cyclin B1- and p53-mediated cell-cycle arrest and apoptosis of human T lymphoblastoid cells. 1545 Apr 19


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