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)

CREB-binding protein (CBP) and highly related p300 protein are transcriptional co-activators that play an essential role in chromatin remodeling through histone acetyltransferase activity and interaction with other transcriptional regulators. In this study, various hematological malignancies, including nine cell lines and 45 clinical samples (32 acute myeloid leukemias (AML), nine acute lymphoblastic leukemias (ALL), two cases of myelodysplastic syndrome (MDS), one multiple myeloma, and one chronic myelogenous leukemia in blast crisis), were examined to ask whether mutation of the CBP and p300 genes could be involved in leukemogenesis. The answer was approached by employing the reverse transcription-polymerase chain reaction and single-strand conformation polymorphism (RT-PCR/SSCP) technique and subsequent sequence analysis. A T-lymphoblastic cell line, CEM had an in-frame 21-base-pair deletion within the bromodomain of its p300 cDNA. Genomic DNA analysis revealed aberrant splicing caused by mutation of the acceptor site of intron 17 from ag to gg, which should interfere with catalytic step II of the pre-mRNA splicing reaction. In 1 MDS patient, a missense mutation was detected, which caused a replacement from Ser to Gly at codon 507 of p300. This is the first report of CBP/p300 mutations in leukemias, which might be relatively rare but nonetheless contribute to pathogenesis in some fraction of cases.
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PMID:Disease-related potential of mutations in transcriptional cofactors CREB-binding protein and p300 in leukemias. 1531 79

Bcr-Abl-independent signaling pathways are known to be involved in imatinib resistance in some patients with chronic myelogenous leukemia (CML). In this study, to find new targets for imatinib-resistant CML displaying loss of Bcr-Abl kinase target dependence, we isolated imatinib-resistant variants, K562/R1, K562/R2, and K562/R3, which showed profound declines of Bcr-Abl levels and its tyrosine kinase activity, from K562 cells. Importantly, the imatinib resistance mechanism in these variants also included aberrant acetylation of nonhistone proteins such as p53, Ku70, and Hsp90 that was due to upregulation of histone deacetylases (HDACs) and down-regulation of histone acetyltransferase (HAT). In comparison with K562 cells, the imatinib-resistant variants showed up-regulation of HDAC1, -2, and -3 (class I HDACs) and class III SIRT1 and down-regulation of CBP/p300 and PCAF with HAT activity, and thereby p53 and cytoplasmic Ku70 were aberrantly acetylated. In addition, these were associated with down-regulation of Bax and up-regulation of Bcl-2. In contrast, the class II HDAC6 level was significantly decreased, and this was accompanied by an increase of Hsp90 acetylation in the imatinib-resistant variants, which was closely associated with loss of Bcr-Abl. These results indicate that alteration of the normal balance of HATs and HDACs leads to deregulated acetylation of Hsp90, p53, and Ku70 and thereby leads to imatinib resistance, suggesting the importance of the acetylation status of apoptosis-related nonhistone proteins in Bcr-Abl-independent imatinib resistance. We also revealed that imatinib-resistant K562 cells were more sensitive to suberoylanilide hydroxamic acid, an HDAC inhibitor, than K562 cells. These findings may have implications for HDAC as a molecular target in imatinib-resistant leukemia cells.
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PMID:Bcr-Abl-independent imatinib-resistant K562 cells show aberrant protein acetylation and increased sensitivity to histone deacetylase inhibitors. 1756 22

Acetylation of histones and nonhistone proteins is a posttranslational modification which plays a major role in the regulation of intracellular processes involved in tumorigenesis. It was shown that different acetylation of proteins correlates with development of leukemia. It is proposed that histone acetyltransferases (HATs) are important novel drug targets for leukemia treatment, however data are still not consistent. Our previous data showed that a derivative of anacardic acid - small molecule MG153, which has been designed and synthesized to optimize the HAT inhibitory potency of anacardic acid, is a potent inhibitor of p300/CBP associated factor (PCAF) acetyltransferase. Here we ask whether inhibition of PCAF acetyltransferase with MG153 will show proapoptotic effects in cells expressing BCR-ABL, which show increased PCAF expression and are resistant to apoptosis. We found that inhibition of PCAF decreases proliferation and induces apoptosis, which correlates with loss of the mitochondrial membrane potential and DNA fragmentation. Importantly, cells expressing BCR-ABL are more sensitive to PCAF inhibition compared to parental cells without BCRABL. Moreover, inhibition of PCAF in BCR-ABL-expressing cells breaks their resistance to DNA damage-induced cell death. These findings provide direct evidence that targeting the PCAF alone or in combination with DNA-damaging drugs shows cytotoxic effects and should be considered as a prospective therapeutic strategy in chronic myeloid leukemia cells. Moreover, we propose that anacardic acid derivative MG153 is a valuable agent and further studies validating its therapeutic relevance should be performed.
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PMID:Inhibition of PCAF by anacardic acid derivative leads to apoptosis and breaks resistance to DNA damage in BCR-ABL-expressing cells. 2315 91