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)

Stille cross-coupling of aryltriflates 10 and dienylstannane 11, oxidation and Horner-Wadsworth-Emmons reaction afforded stereoselectively retinoates 15. Saponification provided the carboxylic acids 8a and 8b, retinoids that incorporate a bulky hydrophobic ring while preserving the 9-cis-geometry of the parent system. In contrast to the pan-RAR/RXR agonistic profile of the lower homologue of 8a, compound 7 (LG100567), retinoids 8 showed selective binding and transactivation of RXR, devoid of significant RAR activation. In PLB985 leukemia cells that require RXR agonists for differentiation compounds 8 induced maturation in the presence of the RAR-selective pan-agonist TTNPB; this effect was blocked by an RXR-selective antagonist.
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PMID:9-cis-retinoic acid analogues with bulky hydrophobic rings: new RXR-selective agonists. 1554 41

Retinoids (derivatives of vitamin A) are signalling molecules that play important roles in cell growth, differentiation and death. Retinoids act through two types of receptors - retinoic acid receptors (RAR alpha, RAR beta and RAR gamma) and retinoid X receptors (RXR alpha, RXR beta and RXR gamma) - which themselves act as ligand-dependent transcription factors. Retinoids are of special interest in cancer research owing to their antiproliferative and cancer-preventative properties. They have been used successfully to cure acute promyelocytic leukaemia (APL) and can suppress carcinogenesis in a variety of tissue types (e.g. skin, lung, breast and oral cancers). Extensive research efforts have been dedicated to elucidating the molecular and cellular networks that are induced by retinoids, and this has recently yielded novel insights into how retinoids can both prevent and combat cancer.
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PMID:Retinoids: potential in cancer prevention and therapy. 1556 96

Leukemic cells are defined by two main biological features: arrest of differentiation at a specific stage compatible with continued proliferation, and enhanced resistance to stress. Recent work shows that the leukemia-associated fusion protein PML-RAR can mediate both biological effects targeting independent pathways, through a unifying mechanism. Differentiation block is achieved through transcriptional silencing of genes physiologically regulated by RAR, which are involved in hematopoietic differentiation. In contrast, enhanced resistance to stress is due to the capacity of the fusion protein to cause degradation of the tumor suppressor p53, thus explaining the puzzling observation that mutations of p53 are remarkably rare in acute myeloid leukemias (AMLs). Interestingly, this latter phenomenon depends on expression of wild-type PML, acting as a molecular bridge between p53 and the fusion protein. Strikingly, both effects require a unifying molecular mechanism: aberrant recruitment of histone deacetylases (HDACs). Therefore, the study of this form of leukemia appears also of interest for a better understanding of the action of HDAC inhibitors, potential antitumor drugs that are at the early stages of clinical studies.
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PMID:Leukemia-associated fusion proteins. Multiple mechanisms of action to drive cell transformation. 1561 39

In the last twenty years, using all-trans retinoic acid (ATRA) as a differentiation inducer, Shanghai Institute of Hematology has achieved an important breakthrough in the treatment of acute promyelocytic leukemia (APL), which realized the theory of reversing phenotype of cells and provided a successful model of differentiation therapy in cancers. Our group first discovered in the world the variant chromosome translocation t(11;17)(q23;q21) of APL, and cloned the PML-RAR alpha, PLZF-RAR alpha and NPM-RAR alpha fusion genes corresponding to the characterized chromosome translocations t(15;17); t(11;17) and t(5;17) in APL. Moreover, establishment of transgenic mice model of APL proved their effects on leukemogenesis. The ability of ATRA to modify the recruitment of nuclear receptor co-repressor with PML-RAR alpha but not PLZF-RAR alpha caused by the variant chromosome translocation elucidated the therapeutic mechanism of ATRA from the molecular level and provides new insight into transcription-modulating therapy. Since 1994, our group has successfully applied arsenic trioxide (As(2)O(3)) in treating relapsed APL patients, with the complete remission rate of 70% - 80%. The molecular mechanism study revealed that As(2)O(3) exerts a dose-dependent dual effect on APL. Low-dose As(2)O(3) induced partial differentiation of APL cells, while the higher dose induced apoptosis. As(2)O(3) binds ubiquitin like SUMO-1 through the lysine 160 of PML, resulting in the degradation of PML-RAR alpha. Taken together, ATRA and As(2)O(3) target the transcription factor PML-RAR alpha, the former by retinoic acid receptor and the latter by PML sumolization, both induce PML-RAR alpha degradation and APL cells differentiation and apoptosis. Because of the different acting pathways, ATRA and As(2)O(3) have no cross-resistance and can be used as combination therapy. Clinical trial in newly diagnosed APL patients showed that ATRA/As(2)O(3) in combination yields a longer disease-free survival time. With the median survival of 18 months, none of the 20 cases in combination treatment relapsed, whereas 7 relapsed in 37 cases in mono-treatment. This is the best clinical effect achieved in treating adult acute leukemia to this day, possibly making APL the first adult curable leukemia. Based on the great success of the pathogenetic gene target therapy in APL, this strategy may extend to other leukemias. Combination of Gleevec and arsenic agents in treating chronic myeloid leukemia has already make a figure both in clinical and laboratory research, aiming at counteracting the abnormal tyrosine kinase activity of ABL and the degradating BCR-ABL fusion protein. In acute myeloid leukemia M(2b), using new target therapy degradating AML1-ETO fusion protein and reducing the abnormal tyrosine kinase activity of c-kit will also lead to new therapeutic management in acute leukemias.
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PMID:[Basic and clinical studies of the gene product-targeting therapy based on leukemogenesis--editorial]. 1574 26

All-trans retinoic acid (ATRA) can induce complete remission in acute promyelocytic leukemia (APL), but resistance to this treatment develops rapidly partly due to increased ATRA metabolism. Among the cytochrome P450s (CYPs) involved in ATRA metabolism, the ATRA-inducible cytochrome P450 26A1 (CYP26A1) is particularly active although the molecular mechanisms involved in its regulation are not well defined in the target leukemia cells. To study CYP26A1 expression and regulation in APL cells, we used the NB4 promyelocytic leukemia cell line. CYP26A1 constitutive expression was barely detectable in NB4 cells, but ATRA could induce high levels of CYP26A1 expression, which reached a maximum at 72h. To further define CYP26A1 induction mechanisms in the NB4 leukemia cells, we used RARs and RXR selective agonists. The RARalpha agonist BMS753 could elicit maturation, as expected, but not CYP26A1 expression. Treatment with the RARbeta agonist BMS641, or the RARbeta/gamma agonist BMS961, could not elicit maturation, as expected, nor induce CYP26A1 expression. Because CYP26A1 expression could not be induced by RAR ligands alone, NB4 cells were then co-treated with the RXR agonist BMS649. The RXR agonist alone could not induce CYP26A1 expression, nor in combination with either the RARbeta agonist or the RARbeta/gamma agonist. However, the combination of the RXR agonist and the RARalpha agonist could elicit a marked induction of CYP26A1 expression. In conclusion, we have shown that CYP26A1 induction is not essential for the granulocytic maturation of NB4 leukemia cells, and that CYP26A1 induction requires the activation of both RARalpha and RXR in these cells.
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PMID:Regulation of CYP26A1 expression by selective RAR and RXR agonists in human NB4 promyelocytic leukemia cells. 1589 39

Recurrent chromosomal translocations involving the RAR alpha locus on chromosome 17 are the hallmark of acute promyelocytic leukemia (APL). The RAR alpha gene fuses to variable partners (PML, PLZF, NPM, NuMA and STAT5B: X genes) leading to the expression of APL-specific fusion proteins with identical RAR alpha moieties. To analyse whether the variable X moiety could affect the activity of the fusion protein in vivo, we generated and characterized, on a comparative basis, NPM/RAR alpha transgenic mice (TM) in which the fusion gene is expressed under the control of a human Cathepsin G (hCG) minigene. We compared the features of the leukemia observed in these TM with those in hCG-PML/RAR alpha and hCG-PLZF/RAR alpha TM. In all three transgenic models, leukemia developed after a variably long latency, with variable penetrance. However, the three leukemias displayed distinct cytomorphological features. hCG-NPM/RAR alpha leukemic cells resembled monoblasts. This phenotype contrasts with what was observed in the hCG-PML/RAR alpha TM model in which the leukemic phase was characterized by the proliferation of promyelocytic blasts. Similarly, hCG-PLZF/RAR alpha TM displayed a different phenotype where terminally differentiated myeloid cells predominated. Importantly, the NPM/RAR alpha oncoprotein was found to localize in the nucleolus, unlike PML/RAR alpha and PLZF/RAR alpha, thus possibly interfering with the normal function of NPM. Similarly to what was observed in human APL patients, we found that NPM/RAR alpha and PML/RAR alpha, but not PLZF/RAR alpha leukemia, was responsive to all-trans retinoic acid (ATRA) or As2O3 treatments. Taken together, our results underscore the critical relevance of the X moiety in dictating the biology of the disease and the activity of the APL fusion oncoprotein.
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PMID:Leukemia with distinct phenotypes in transgenic mice expressing PML/RAR alpha, PLZF/RAR alpha or NPM/RAR alpha. 1633 Dec 71

The study was aimed to detect expression rate of survivin gene in APL cell and to explore the relationship between its expression and clinical manifestation. PML/RARalpha and survivin mRNA expression were analyzed by using reverse transcriptase polymerase chain reaction (RT-PCR) technique. The results showed: (1) the survivin gene expression was detected in NB4 cell line. By treatment with ATRA, survivin mRNA expression in NB4 cell gradually decreased along with time delay and almost could not be detected at the 72th hour. (2) the positive and negative rate of survivin mRNA expression was 67% and 33% respectively, while in all 36 cases of de novo and relapse APL patients, the PML/RAR(alpha) fusion gene expression was positive. In 22 cases at remission stage, the PML/RARalpha fusion gene expression was negative, and the positive and negative rate of survivin mRNA expression was 36% and 64% respectively. The survivin mRNA expression positive rates in the de novo group, relapse group and PML/RARalpha fusion gene L-type positive group were obviously higher than those in remission period group (P < 0.05) and were significantly lower than those in acute leukemia group (P < 0.05, < 0.001). (3) whether the survivin mRNA expression was positive or negative in 36 cases of de novo and relapse APL patients, all the 36 cases could obtain complete remission. 4 APL patients with positive expression of survivin mRNA had DIC and serious infection (one patient died). The clinical symptom showed slight skin or mucosa bleeding, fever and asthenic in the patients with negative expression of survivin mRNA. When 2 APL patients with positive expression of survivin mRNA had been treated with ATRA, induction differentiation sign in their peripheral blood and bone marrow figures was not obvious. It is concluded that the survivin gene positive expression rate is lower in acute promyelocytic leukemia than that in any other types of leukemia and is related to clinical manifestation.
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PMID:[Expression of survivin gene in NB4 cell line and cells of acute promyelocytic leukemia and its anti-apoptosis and clinical significance]. 1663 9

Human myeloid leukemias provide models of maturation arrest and differentiation therapy of cancer. The genetic lesions of leukemia result in a block of differentiation (maturation arrest) that allows myeloid leukemic cells to continue to proliferate and/or prevents the terminal differentiation and apoptosis seen in normal white blood cells. In chronic myeloid leukemia, the bcr-abl (t9/22) translocation produces a fusion product that is an activated tyrosine kinase resulting in constitutive activation cells at the myelocyte level. This activation may be inhibited by imatinib mesylate (Gleevec, STI-571), which blocks the binding of ATP to the activated tyrosine kinase, prevents phosphorylation, and allows the leukemic cells to differentiate and undergo apoptosis. In acute promyelocytic leukemia, fusion of the retinoic acid receptor-alpha with the gene coding for promyelocytic protein, the PML-RAR alpha (t15:17) translocation, produces a fusion product that blocks the activity of the promyelocytic protein, which is required for formation of the granules of promyelocytes and prevents further differentiation. Retinoic acids bind to the retinoic acid receptor (RAR alpha) component of the fusion product, resulting in degradation of the fusion protein by ubiquitinization. This allows normal PML to participate in granule formation and differentiation of the promyelocytes. In one common type of acute myeloid leukemia, which results in maturation arrest at the myeloid precursor level, there is a mutation of FLT3, a transmembrane tyrosine kinase, which results in constitutive activation of the IL-3 receptor. This may be blocked by agents that inhibit farnesyl transferase. In each of these examples, specific inhibition of the genetically altered activation molecules of the leukemic cells allows the leukemic cells to differentiate and die. Because acute myeloid leukemias usually have mutation of more than one gene, combinations of specific inhibitors that act on the effects of different specific genetic lesions promises to result in more effective and permanent treatment.
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PMID:Leukemia: stem cells, maturation arrest, and differentiation therapy. 1714 56

The promyelocytic leukaemia gene (Pml) is a tumor suppressor identified in acute promyelocytic leukaemia (APL), where it is fused to RAR alpha gene as a result of the chromosomal translocation t(15;17). Pml encodes both nuclear and cytoplasmic isoforms. While nuclear PML has been intensively investigated, cytoplasmic PML proteins are less characterized. PML nuclear isoforms (nPML) are the essential components of subnuclear structures referred to as PML nuclear bodies (PML-NB). In response to cellular insults such as DNA damage and oncogenic activation, nPML modulates p53 activity through CBP-mediated acetylation and activates its pro-apoptotic and growth suppressive functions. Two missense mutations resulting in truncated PML cytoplasmic proteins (Mut PML) have been identified in aggressive APL cases. Here we report that cytoplasmic PML is able to induce the relocation of nPML to the cytoplasm, thus reducing the number of PML-NBs. Remarkably, Mut PML inhibits p53 transcriptional, growth suppressive, and apoptotic functions, thus suggesting that cytoplasmic expression of PML has an impact on survival through inhibition of nuclear PML. Overall our findings shed new light on the role of PML cytoplasmic proteins in the regulation of p53.
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PMID:A cytoplasmic PML mutant inhibits p53 function. 1717 28

On the basis of the observations that chalcone 7 (MX781) and some related adamantyl arotinoids (AdArs) inhibit IkappaB alpha kinase beta (IKKbeta) activity, inhibit cell growth, and induce apoptosis in cancer cells, a new series of AdArs structurally related to 7 have been designed and synthesized. Modifications were intended to reduce or eliminate RAR activity, and we evaluated the effect of the novel analogues of 7 on IKKbeta activity and proliferation of a variety of cancer cell lines (leukemia, Jurkat; prostate, PC-3; breast carcinomas, T47D, MDA-MB-468). Consistent with the design principles, the biological activities of these AdArs do not appear to be RAR-mediated, since most analogues are unable to activate RAR-mediated transactivation and exhibit significantly diminished antagonist activity. All compounds are capable of inducing apoptosis in Jurkat cells, as demonstrated by elevated DEVDase activity and externalization of phosphatidylserine. Several of the analogues elicit stronger growth inhibitory activity against prostate (PC-3) and breast (MDA-MB-468) carcinoma cells, which contain elevated basal IKK activity; this antiproliferative activity correlates with increased inhibition of recombinant IKKbeta in vitro, suggesting that the anticancer activities of these AdArs might be related to the inhibition of IKK/NFkappaB signaling.
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PMID:Inhibition of IkappaB kinase-beta and anticancer activities of novel chalcone adamantyl arotinoids. 1870 57


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