A Worldwide Support Network For Chronic Myelogenous Leukemia
Posted by rob on October 28, 2010 under Uncategorized | 
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Second-generation tyrosine kinase inhibitors in chronic myelogenous leukemia: before or after imatinib?
Cancer. 2010 Oct 26;
Authors: Tefferi A
PMID: 20979064 [PubMed - as supplied by publisher]
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Postremission gemtuzumab ozogamicin for elderly patients with acute myelogenous leukemia with favorable characteristics and comorbid conditions.
Int J Hematol. 2010 Oct 28;
Authors: Ichikawa M, Hangaishi A, Nannya Y, Kurokawa M
PMID: 20978876 [PubMed - as supplied by publisher]
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JAK2 Translocations in hematological malignancies: Review of the literature.
J Assoc Genet Technol. 2010;36(3):107-9
Authors: Ho K, Valdez F, Garcia R, Tirado CA
JAK2 is a cytoplasmic tyrosine kinase whose gene is located on chromosome 9p24. It is involved in the regulation of different cytokines and growth factors and plays an important role in the diagnosis and treatment of myeloproliferative neoplasms (Smith et al., 2008). Translocations involving the JAK2 locus are uncommon with just a few cases described in the literature, and they usually lead to a fusion protein with JAK2 (Patnaik et al., 2010). Chromosome 9p24 abnormalities have been described in myeloid and lymphoid neoplasms including chronic myelogenous leukemia (CML), acute megakaryoblastic leukemia, CD10+ B-cell acute lymphoblastic leukemia, T-cell ALL and chronic myeloproliferative disorders (CMD) (Smith et al., 2008; Lacronique et al., 1997). Although the breakpoints of each translocation are known, characterization of the partner gene has not been done in many of the cases reported due to insufficient sample or other factors. In the present study we review all translocations involving JAK2 that have been reported in the literature.
PMID: 20978341 [PubMed - in process]
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Participation of CYP2C8 and CYP3A4 in the N-demethylation of imatinib in human hepatic microsomes.
Br J Pharmacol. 2010 Nov;161(5):1059-69
Authors: Nebot N, Crettol S, D’Esposito F, Tattam B, Hibbs DE, Murray M
BACKGROUND AND PURPOSE Imatinib is a clinically important inhibitor of tyrosine kinases that are dysregulated in chronic myelogenous leukaemia and gastrointestinal stromal tumours. Inter-individual variation in imatinib pharmacokinetics is extensive, and influences drug safety and efficacy. Hepatic cytochrome P450 (CYP) 3A4 has been implicated in imatinib N-demethylation, but the clearance of imatinib decreases during prolonged therapy. CYP3A phenotype correlates with imatinib clearance at the commencement of therapy, but not at steady state. The present study evaluated the possibility that multiple CYPs may contribute to imatinib oxidation in liver. EXPERIMENTAL APPROACH Imatinib biotransformation in human liver microsomes (n= 20) and by cDNA-expressed CYPs was determined by LC-MS. Relationships between imatinib N-demethylation and other drug metabolizing CYPs were assessed. KEY RESULTS N-desmethylimatinib formation was correlated with microsomal oxidation of the CYP3A4 substrates testosterone (?= 0.60; P < 0.01) and midazolam (?= 0.46; P < 0.05), and the CYP2C8 substrate paclitaxel (?= 0.58; P < 0.01). cDNA-derived CYPs 2C8, 3A4, 3A5 and 3A7 supported imatinib N-demethylation, but 10 other CYPs were inactive; in kinetic studies, CYP2C8 was a high-affinity enzyme with a catalytic efficiency ?15-fold greater than those of CYPs 3A4 and 3A5. The CYP3A inhibitors ketoconazole and troleandomycin, and the CYP2C8 inhibitors quercetin and paclitaxel decreased imatinib oxidation. From molecular modelling, the imatinib structure could be superimposed on a pharmacophore for CYP2C8 substrates. CONCLUSIONS AND IMPLICATIONS CYP2C8 and CYPs 3A contribute to imatinib N-demethylation in human liver. The involvement of CYP2C8 may account in part for the wide inter-patient variation in imatinib pharmacokinetics observed in clinical practice.
PMID: 20977456 [PubMed - in process]
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The antimicrobial peptide human cationic antimicrobial protein-18/cathelicidin LL-37 as a putative growth factor for malignant melanoma.
Br J Dermatol. 2010 Nov;163(5):959-67
Authors: Kim JE, Kim HJ, Choi JM, Lee KH, Kim TY, Cho BK, Jung JY, Chung KY, Cho D, Park HJ
Background? Recent evidence suggests cathelicidin LL-37 to be a growth factor for various human cancers such as lung cancer, ovarian cancer and breast cancer. However, the effect of LL-37 against malignant skin cancer has not been reported. Objectives? To investigate whether the human cathelicidin LL-37 is involved in the carcinogenesis of various skin tumours. Methods? Human cationic antimicrobial protein-18 (hCAP-18)/LL-37 production in several cell lines including HaCaT, a chronic myelogenous leukaemia (CML) cell line and various melanoma cell lines was examined using reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay. Immunohistochemical analysis of melanoma, nonmelanoma skin cancer and precancerous and benign skin lesions was performed. After adding LL-37 to a melanoma cell line, tumour cell proliferation, migration and invasion were investigated. Results? Human malignant melanoma cell lines overexpressed hCAP-18/LL-37 mRNA and peptide compared with HaCaT and CML cell lines. Immunohistochemistry showed that the peptide was strongly expressed in malignant melanoma and moderately expressed in squamous cell carcinoma, whereas basal cell carcinoma, precancerous lesions and seborrhoeic keratosis showed no or weak expression. LL-37 also stimulated melanoma cell proliferation, migration and invasion in vitro. Conclusions? Cathelicidin LL-37 was primarily expressed in human malignant skin cancer. LL-37 promoted melanoma cell proliferation, migration and invasion in vitro. We report that an increase in the level of LL-37 is associated with malignant skin tumours such as malignant melanoma. These results highlight the importance of LL-37 in the malignant tendency of skin tumours.
PMID: 20977442 [PubMed - in process]
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Properties of CD34+ CML stem/progenitor cells that correlate with different clinical responses to imatinib mesylate.
Blood. 2010 Sep 23;116(12):2112-21
Authors: Jiang X, Forrest D, Nicolini F, Turhan A, Guilhot J, Yip C, Holyoake T, Jorgensen H, Lambie K, Saw KM, Pang E, Vukovic R, Lehn P, Ringrose A, Yu M, Brinkman RR, Smith C, Eaves A, Eaves C
Imatinib mesylate (IM) induces clinical remissions in chronic-phase chronic myeloid leukemia (CML) patients but IM resistance remains a problem. We recently identified several features of CML CD34(+) stem/progenitor cells expected to confer resistance to BCR-ABL-targeted therapeutics. From a study of 25 initially chronic-phase patients, we now demonstrate that some, but not all, of these parameters correlate with subsequent clinical response to IM therapy. CD34(+) cells from the 14 IM nonresponders demonstrated greater resistance to IM than the 11 IM responders in colony-forming cell assays in vitro (P < .001) and direct sequencing of cloned transcripts from CD34(+) cells further revealed a higher incidence of BCR-ABL kinase domain mutations in the IM nonresponders (10%-40% vs 0%-20% in IM responders, P < .003). In contrast, CD34(+) cells from IM nonresponders and IM responders were not distinguished by differences in BCR-ABL or transporter gene expression. Interestingly, one BCR-ABL mutation (V304D), predicted to destabilize the interaction between p210(BCR-ABL) and IM, was detectable in 14 of 20 patients. T315I mutant CD34(+) cells found before IM treatment in 2 of 20 patients examined were preferentially amplified after IM treatment. Thus, 2 properties of pretreatment CML stem/progenitor cells correlate with subsequent response to IM therapy. Prospective assessment of these properties may allow improved patient management.
PMID: 20574046 [PubMed - indexed for MEDLINE]
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Activity of the multitargeted kinase inhibitor, AT9283, in imatinib-resistant BCR-ABL-positive leukemic cells.
Blood. 2010 Sep 23;116(12):2089-95
Authors: Tanaka R, Squires MS, Kimura S, Yokota A, Nagao R, Yamauchi T, Takeuchi M, Yao H, Reule M, Smyth T, Lyons JF, Thompson NT, Ashihara E, Ottmann OG, Maekawa T
Despite promising clinical results from imatinib mesylate and second-generation ABL tyrosine kinase inhibitors (TKIs) for most BCR-ABL(+) leukemia, BCR-ABL harboring the mutation of threonine 315 to isoleucine (BCR-ABL/T315I) is not targeted by any of these agents. We describe the in vitro and in vivo effects of AT9283 (1-cyclopropyl-3[5-morpholin-4yl methyl-1H-benzomidazol-2-yl]-urea), a potent inhibitor of several protein kinases, including Aurora A, Aurora B, Janus kinase 2 (JAK2), JAK3, and ABL on diverse imatinib-resistant BCR-ABL(+) cells. AT9283 showed potent antiproliferative activity on cells transformed by wild-type BCR-ABL and BCR-ABL/T315I. AT9283 inhibited proliferation in a panel of BaF3 and human BCR-ABL(+) cell lines both sensitive and resistant to imatinib because of a variety of mechanisms. In BCR-ABL(+) cells, we confirmed inhibition of substrates of both BCR-ABL (signal transducer and activator of transcription-5) and Aurora B (histone H3) at physiologically achievable concentrations. The in vivo effects of AT9283 were examined in several mouse models engrafted either subcutaneously or intravenously with BaF3/BCR-ABL, human BCR-ABL(+) cell lines, or primary patient samples expressing BCR-ABL/T315I or glutamic acid 255 to lysine, another imatinib-resistant mutation. These data together support further clinical investigation of AT9283 in patients with imatinib- and second-generation ABL TKI-resistant BCR-ABL(+) cells, including T315I.
PMID: 20548094 [PubMed - indexed for MEDLINE]
