Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0023473 (chronic myeloid leukemia)
 18,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Celecoxib, a selective cyclooxygenase-2 (COX-2) inhibitor, is the only non-steroidal anti-inflammatory drug so far which has been approved by the FDA for adjuvant treatment of patients with familial adenomatous polyposis. The molecular mechanism responsible for the anti-cancer effects of celecoxib is not fully understood. There is little data on the potential role of COX-2 in lymphoma pathogenesis. In view of the reported induction of apoptosis in cancer cells by cyclooxygenase-2 inhibitors, the present study is undertaken to test the effect of celecoxib on human chronic myeloid leukemia cell line, K562 and other hematopoietic cancer cell lines like Jurkat (human T lymphocytes), HL60 (human promyelocytic leukemia) and U937 (human macrophage). Treatment of these cells with celecoxib (10-100 microM) dose-dependently, reduced cell growth with arrest of the cell cycle at G0/G1 phase and induction of apoptosis. Further mechanism of apoptosis induction was elucidated in detail in K562 cell line. Apoptosis was mediated by release of cytochrome c into the cytoplasm and cleavage of poly (ADP-ribose) polymerase-1 (PARP-1). This was followed by DNA fragmentation. The level of anti-apoptotic protein Bcl-2 was decreased without any change in the pro-apoptotic Bax. Celecoxib also inhibited NF-kB activation. Celecoxib thus potentiates apoptosis as shown by MTT assay, cytochrome c leakage, PARP cleavage, DNA fragmentation, Bcl-2 downregulation and possibly by inhibiting NF-kB activation.
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PMID:Anti-proliferative and apoptotic effects of celecoxib on human chronic myeloid leukemia in vitro. 1591 Oct 99

The complex of lanthanum (III) was synthesized reacting the respective inorganic salt with 5-aminoorotic acid in amounts equal to the metal:ligand molar ratio of 1:3. The complex was prepared by adding an aqueous solution of lanthanum (III) nitrate to an aqueous solution of the ligand, subsequently raising the pH of the mixture gradually to approx. 5.0 through addition of a dilute solution of sodium hydroxide. The structure of the final complex was determined by means of spectral data (IR, Raman,( 1)H-NMR) and elemental analysis. Significant differences in the IR spectrum of the complex were observed as compared to the spectrum of the ligand. A comparative analysis of the Raman spectrum of the complex with that of the free 5-aminoorotic acid allowed a straightforward assignment of the vibrations of the ligand groups involved in coordination. The ligand and the complex were tested for the cytotoxic activities on the chronic myeloid leukemia derived K-562, overexpressing the BCR-ABL fusion protein and the non-Hodgkin lymphoma derived DOHH-2, characterized by a re-expression of the anti-apoptotic protein bcl-2 cell lines. The results obtained indicate that the tested compounds exerted a considerable cytotoxic activity upon the evaluated cell lines in a concentration-dependent matter, which enabled the construction of dose-response curves and the calculation of the corresponding IC(50 )values. The inorganic salt exerted a very weak cytotoxic effect on these cells, which is in contrast to the lanthanum (III) complex.
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PMID:New lanthanum (III) complex--synthesis, characterization, and cytotoxic activity. 1704 90

The complexes of gadolinium(III) and dysprosium(III) were synthesized by reaction of the respective inorganic salts with 3,5-pyrazoledicarboxylic acid in amounts equal to metal to ligand molar ratio of 1 : 2. The structures of the final complexes were determined by means of spectral and elemental analyses. To help further the binding mode elucidation in the new Gd(III)- and Dy(III)-complexes of H(3)pdc, detailed vibrational analysis was performed on the basis of comparison of experimental vibrational spectra of the ligand and its Ln(III)-complexes using data theoretically predicted by us earlier, as well as data from the literature about related compounds. Significant differences in the IR and Raman spectra of the complexes were observed as compared to the spectra of the ligand. The ligand and the complexes were tested for their cytotoxic activities on the chronic myeloid leukemia-derived K-562, overexpressing the BCR-ABL fusion protein and the non-Hodgkin lymphoma-derived DOHH-2, characterized by a re-expression of the anti-apoptotic protein bcl-2 cell lines. The results obtained indicate that the tested compounds exerted a considerable cytotoxic activity upon the evaluated cell lines in a concentration-dependent manner, which enabled the construction of dose-response curves and the calculation of the corresponding IC(50) values. The inorganic salts exerted a very weak cytotoxic effect on these cells. This is in contrast to the lanthanide complexes, which exhibited potent cytotoxic activity, even more than the activity of cisplatin towards K-562 and DOHH-2 cell lines.
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PMID:Cytotoxic activity of Gd(III)- and Dy(III)-complexes. 1799 6

This study was aimed to investigate the effect of STI571, an inhibitor of tyrosine kinase, on the proliferation and apoptosis of chronic myelogenous leukemia (CML) cells as well as expression of anti-apoptotic protein Mcl-1, and to explore the possible role of Mcl-1 in apoptosis-inducing mechanism. K562 cell line was used to observe the effect of STI571 on CML cells. Proliferation and cytotoxicity were analyzed by MTT assay. The apoptotic cells were labelled with Annexin V-FITC and PI and then analyzed by flow cytometry. The expression of apoptotic-related proteins in K562 cells was determined by Western blot with specific antibodies. The results showed that STI571 significantly inhibited the proliferation and induced apoptosis of K562 cells in a dose-and time-dependent manner. Coincidently, the protein phosphorylation on tyrosine residues was reduced and the expressions of anti-apoptotic protein Mcl-1 and Bcl-xl were down-regulated after exposure to STI571. It is concluded that STI571 induces the apoptosis of CML cells by down-regulating the expressions of Mcl-1 and Bcl-xl, which suggests that Mcl-1 and Bcl-xl may play an important role in anti-apoptotic process of CML cells.
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PMID:[STI571 induces apoptosis of K562 cells through down-regulation of anti-apoptotic protein Mcl-1 and Bcl-xl expression]. 1808 62

Busulfan (Bu) resistance is a major obstacle to hematopoietic stem cell transplantation (HSCT) of patients with chronic or acute myelogenous leukemia (CML or AML). We used gene expression analysis to identify cellular factors underlying Bu resistance. Two Bu-resistant leukemia cell lines were established, characterized and analyzed for differentially expressed genes. The CML B5/Bu250(6) cells are 4.5-fold more resistant to Bu than their parental B5 cells. The AML KBM3/Bu250(6) cells are 4.0-fold more Bu-resistant than KBM3 parental cells. Both resistant sublines evade Bu-mediated G2-arrest and apoptosis with altered regulations of CHK2 and CDC2 proteins, constitutively up-regulated anti-apoptotic genes (BCL-X(L), BCL2, BCL2L10, BAG3 and IAP2/BIRC3) and down-regulated pro-apoptotic genes (BIK, BNIP3, and LTBR). Bu-induced apoptosis is partly mediated by activation of caspases; use of the inhibitor Z-VAD-FMK completely abrogated PARP1 cleavage and reduced apoptosis by approximately 50%. Furthermore, Bu resistance in these cells may be attributed in part to up-regulation of HSP90 protein and activation of STAT3. The inhibition of HSP90 with geldanamycin attenuated phosphorylated STAT3 and made B5/Bu250(6) and KBM3/Bu250(6) more Bu-sensitive. The analysis of cells derived from patients classified as either clinically resistant or sensitive to high-dose Bu-based chemotherapy indicated alterations in gene expression that were analogous to those observed in the in vitro model cell lines, confirming the potential clinical relevance of this model for Bu resistance.
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PMID:Altered gene expression in busulfan-resistant human myeloid leukemia. 1833 23

The CALGB studied the feasibility and effectiveness of adding oblimersen (G3139; Genasense) to imatinib mesylate (IM) in imatinib-resistant chronic phase chronic myeloid leukemia (CML) patients. We hypothesised that IM resistant CML cells are no longer being driven to proliferate by Bcr/Abl activity alone. Instead, the anti-apoptotic protein Bcl-2 would regulate one of the pathways controlling growth and/or viability. Thus, blocking both Bcr/Abl and Bcl-2 simultaneously would result in hematologic and cytogenetic improvement. Oblimersen was administered via continuous intravenous infusion over 10 days every 21 days, along with daily IM. Doses of both drugs were escalated in 3 cohorts; the initial dose of IM was 600 mg/day. Response was defined as a decrease by >30% in the percentage of t(9;22) metaphase cells. Twelve patients had primary and nine had secondary imatinib resistance. Ten patients received 4 mg/kg/day oblimersen/600 mg IM, six patients received 7 mg/kg/day oblimersen/600 mg IM and five patients received 7 mg/kg/day oblimersen/800 mg IM. Only two (9.5%) patients achieved a decrease by >30% in the percentage of t(9;22) metaphase cells. Although the combination of oblimersen and IM is safe and feasible, we did not observe clinical benefit in these patients with imatinib-resistant CML using these doses and schedule.
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PMID:Feasibility of administering oblimersen (G3139; Genasense) with imatinib mesylate in patients with imatinib resistant chronic myeloid leukemia--Cancer and leukemia group B study 10107. 1860 12

The Bcr-abl kinase inhibitor STI571 produces clinical responses in most patients with Chronic Myeloid Leukemia (CML); however, development of resistance limits utility. One strategy to overcome STI571 resistance is to decrease the level/activity of Bcr-abl. We reported that disruption of the anti-apoptotic protein Survivin promoted STI571-induced apoptosis in Bcr-abl(+) K562 cells, through caspase-dependent Bcr-abl degradation. To investigate the utility of Survivin disruption in drug-resistant CML cells, we generated STI571-resistant K562 cells by long-term culture with STI571. In contrast to parental cells, where Survivin disruption enhances STI571-induced apoptosis, Survivin disruption in STI571-resistant cells failed to promote STI571-induced apoptosis; rather it protected cells from STI571 and other apoptosis-inducing compounds. Even though Survivin levels were similar in parental and STI571-resistant K562 cells, Survivin disruption in STI571-resistant cells increased telomerase activity, likely due to Bcr-abl/c-abl degradation. Our results indicate that emergence of STI571 resistance in Bcr-abl(+) K562 cells results from induction of additional pathways that circumvent STI571-responsiveness.
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PMID:Disruption of Survivin in K562 cells elevates telomerase activity and protects cells against apoptosis induced by the Bcr-abl kinase inhibitor STI571. 1907 92

The existence of leukemia stem cells (LSCs) responsible for tumor maintenance has been firmly established. Therefore, therapeutic targeting of these LSCs may have a profound impact on cancer eradication. The anti-apoptotic protein Bcl2 has been proposed as a therapeutic target, but its role in LSC biology has not been investigated. In order to understand the role of Bcl2 in LSC generation and maintenance, we have taken advantage of our Sca1-BCRABLp210 mouse model of human chronic myeloid leukemia and bcl2 gene-targeted mice. This study provides genetic evidence that the inhibition of Bcl2 is not critical for the generation, selection or maintenance of the tumor initiating and maintaining cells in mice.
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PMID:Bcl2 is not required for the development and maintenance of leukemia stem cells in mice. 2029 24

Chronic myeloid leukemia (CML) is a cytogenetic disorder resulting from formation of the Philadelphia chromosome (Ph), that is, the t(9;22) chromosomal translocation and the formation of the BCR-ABL1 fusion protein. Tyrosine kinase inhibitors (TKI), such as imatinib and nilotinib, have emerged as leading compounds with which to treat CML. t(9;22) is not restricted to CML, 20-30% of acute lymphoblastic leukemia (ALL) cases also carry the Ph. However, TKIs are not as effective in the treatment of Ph+ ALL as in CML. In this study, the Ph+ cell lines JURL-MK2 and SUP-B15 were used to investigate TKI resistance mechanisms and the sensitization of Ph+ tumor cells to TKI treatment. The annexin V/PI (propidium iodide) assay revealed that nilotinib induced apoptosis in JURL-MK2 cells, but not in SUP-B15 cells. Since there was no mutation in the tyrosine kinase domain of BCR-ABL1 in cell line SUP-B15, the cells were not generally unresponsive to TKI, as evidenced by dephosphorylation of the BCR-ABL1 downstream targets, Crk-like protein (CrkL) and Grb-associated binder-2 (GAB2). Resistance to apoptosis after nilotinib treatment was accompanied by the constitutive and nilotinib unresponsive activation of the phosphoinositide 3-kinase (PI3K) pathway. Treatment of SUP-B15 cells with the dual PI3K/mammalian target of rapamycin (mTOR) inhibitor BEZ235 alone induced apoptosis in a low percentage of cells, while combining nilotinib and BEZ235 led to a synergistic effect. The main role of PI3K/mTOR inhibitor BEZ235 and the reason for apoptosis in the nilotinib-resistant cells was the block of the translational machinery, leading to the rapid downregulation of the anti-apoptotic protein MDM2 (human homolog of the murine double minute-2). These findings highlight MDM2 as a potential therapeutic target to increase TKI-mediated apoptosis and imply that the combination of PI3K/mTOR inhibitor and TKI might form a novel strategy to combat TKI-resistant BCR-ABL1 positive leukemia.
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PMID:Inhibition of PI3K/mTOR overcomes nilotinib resistance in BCR-ABL1 positive leukemia cells through translational down-regulation of MDM2. 2434 24

Iminosugars have gained a remarkable importance as new therapeutic agents since 1966. In this study, compounds A and B, two iminosugar analogs synthesized previously, showed an inhibition of the growth of K562 cells. They allowed cell cycle arrested at the G0/G1 phase, promoted apoptotic activities and also lowered the mitochondrial membrane potential. Further exploration of the apoptosis mechanism revealed that compound B significantly suppressed the expression of Hsp70, which is a major anti-apoptotic molecular chaperone. Significant decrease was also found in the expression of Akt, a serine/threonine-specific protein kinase with anti-apoptosis activities also known as protein kinase B (PKB). At mitochondria level in comparison with compound A, compound B brought a better promotion in the expression of pro-apoptotic protein Bad in Bcl-2 family. As a result of the promotion, the expression of anti-apoptotic protein Bcl-xL was down-regulated. Cytochrome c was released, activating the intrinsic signaling pathways of caspase and resulting in the occurrence of cascade reaction. In addition, compound B stimulated autophagy effectively by up-regulating Beclin 1, thus causing the conversion of LC3-I to LC3-II through Akt/mTOR signaling pathway. In summary, these results indicated that compounds A and B induced cell death through multiple pathways. The disclosed results not only provide an evidence of antitumor activity of iminosugars as a foundation for further studies, but also may find potential applications in chronic myeloid leukemia therapy as new heat shock protein inhibitors and autophagy inducer.
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PMID:Cell cycle arrest, apoptosis and autophagy induced by iminosugars on K562 cells. 2465 62


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