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Xing H, Yang X, Liu T, Lin J, Chen X, Gong Y. The study of resistant mechanisms and reversal in an imatinib resistant Ph+ acute lymphoblastic leukemia cell line. Leuk Res 2012; 36:509-13. [PMID: 22285507 DOI: 10.1016/j.leukres.2011.12.018] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2011] [Revised: 11/16/2011] [Accepted: 12/22/2011] [Indexed: 02/05/2023]
Abstract
In this study, we established an imatinib resistant Ph+ acute lymphoblastic leukemia (ALL) cell line SUP-B15/RI in vitro and studied the mechanism of imatinib resistance. Our results showed that the BCR-ABL1 fusion gene and the mdr1 gene were 6.1 times and 1.7 times, respectively, as high as that of parental SUP-B15 cell line. We found no mutation in the Abl kinase domain of SUP-B15/RI. Furthermore, the detection of cell signaling pathway of PI3K/AKT/mTOR, RAS/RAF, NF-κB, JNK and STAT showed the up-regulation of phosphorylation of AKT, mTOR, P70S6K, and RAF, ERK, and MEK, down-regulation of PTEN and 4EBP-1, and no change in other cell signaling pathways in SUP-B15/RI. However, dasatinib and nilotinib showed partial resistance. Interestingly, bortezomib had no resistance. Imatinib combination with rapamycin had synergistic effect on overcoming the resistance. Altogether, over-expression of BCR-ABL1 and mdr1 gene were involved in the resistance mechanisms, and up-regulation of the cell signaling pathways of PI3K/AKT/mTOR, RAS/RAF in SUP-B15/RI cell line may be correlated with them. The SUP-B15/RI cell line was also resistant to the second generation tyrosine kinase, dasatinib, and nilotinib, not bortezomib. The combination of imatinib with rapamycin can partially overcome the resistance and blockade of the ubiquitin-proteasome can be also a promising pathway to overcome imatinib resistance.
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Affiliation(s)
- Hongyun Xing
- Department of Hematology, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital of Sichuan University, Chengdu, China
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Modeling of molecular interaction between apoptin, BCR-Abl and CrkL--an alternative approach to conventional rational drug design. PLoS One 2012; 7:e28395. [PMID: 22253690 PMCID: PMC3254606 DOI: 10.1371/journal.pone.0028395] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2011] [Accepted: 11/07/2011] [Indexed: 12/02/2022] Open
Abstract
In this study we have calculated a 3D structure of apoptin and through modeling and docking approaches, we show its interaction with Bcr-Abl oncoprotein and its downstream signaling components, following which we confirm some of the newly-found interactions by biochemical methods. Bcr-Abl oncoprotein is aberrantly expressed in chronic myelogenous leukaemia (CML). It has several distinct functional domains in addition to the Abl kinase domain. The SH3 and SH2 domains cooperatively play important roles in autoinhibiting its kinase activity. Adapter molecules such as Grb2 and CrkL interact with proline-rich region and activate multiple Bcr-Abl downstream signaling pathways that contribute to growth and survival. Therefore, the oncogenic effect of Bcr-Abl could be inhibited by the interaction of small molecules with these domains. Apoptin is a viral protein with well-documented cancer-selective cytotoxicity. Apoptin attributes such as SH2-like sequence similarity with CrkL SH2 domain, unique SH3 domain binding sequence, presence of proline-rich segments, and its nuclear affinity render the molecule capable of interaction with Bcr-Abl. Despite almost two decades of research, the mode of apoptin's action remains elusive because 3D structure of apoptin is unavailable. We performed in silico three-dimensional modeling of apoptin, molecular docking experiments between apoptin model and the known structure of Bcr-Abl, and the 3D structures of SH2 domains of CrkL and Bcr-Abl. We also biochemically validated some of the interactions that were first predicted in silico. This structure-property relationship of apoptin may help in unlocking its cancer-selective toxic properties. Moreover, such models will guide us in developing of a new class of potent apoptin-like molecules with greater selectivity and potency.
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53
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Kreil S, Waghorn K, Ernst T, Chase A, White H, Hehlmann R, Reiter A, Hochhaus A, Cross NCP. A polymorphism associated with STAT3 expression and response of chronic myeloid leukemia to interferon α. Haematologica 2011; 95:148-52. [PMID: 20065083 DOI: 10.3324/haematol.2009.011510] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Interferon alpha (IFN) induces variable responses in chronic myeloid leukemia (CML), with 8-30% of early chronic phase cases achieving a complete cytogenetic response. We hypothesized that polymorphic differences in genes encoding IFN signal transduction components might account for different patient responses. We studied 174 IFN-treated patients, of whom 79 achieved less than 35% Philadelphia-chromosome (Ph) positive metaphases (responders) and 95 failed to show any cytogenetic response (more than 95% Ph-positive metaphases; non-responders). We compared 17 single nucleotide polymorphisms (SNPs) at IFNAR1, IFNAR2, JAK1, TYK2, STAT1, STAT3 and STAT5a/b between the two groups and found a significant difference for rs6503691, a SNP tightly linked to STAT5a, STAT5b and STAT3 (minor allele frequency 0.16 for non-responders; 0.06 for responders, P=0.007). Levels of STAT3 mRNA correlated with rs6503691 genotype (P<0.001) as assessed by real time quantitative PCR and therefore we conclude that rs6503691 is associated with the STAT3 expression levels and response of CML patients to IFN.
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Affiliation(s)
- Sebastian Kreil
- Wessex Regional Genetics Laboratory, Salisbury District Hospital, Salisbury, UK
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54
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SHP-1 expression accounts for resistance to imatinib treatment in Philadelphia chromosome-positive cells derived from patients with chronic myeloid leukemia. Blood 2011; 118:3634-44. [PMID: 21821701 DOI: 10.1182/blood-2011-03-341073] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
We prove that the SH2-containing tyrosine phosphatase 1 (SHP-1) plays a prominent role as resistance determinant of imatinib (IMA) treatment response in chronic myelogenous leukemia cell lines (sensitive/KCL22-S and resistant/KCL22-R). Indeed, SHP-1 expression is significantly lower in resistant than in sensitive cell line, in which coimmunoprecipitation analysis shows the interaction between SHP-1 and a second tyrosine phosphatase SHP-2, a positive regulator of RAS/MAPK pathway. In KCL22-R SHP-1 ectopic expression restores both SHP-1/SHP-2 interaction and IMA responsiveness; it also decreases SHP-2 activity after IMA treatment. Consistently, SHP-2 knocking-down in KCL22-R reduces either STAT3 activation or cell viability after IMA exposure. Therefore, our data suggest that SHP-1 plays an important role in BCR-ABL-independent IMA resistance modulating the activation signals that SHP-2 receives from both BCR/ABL and membrane receptor tyrosine kinases. The role of SHP-1 as a determinant of IMA sensitivity has been further confirmed in 60 consecutive untreated patients with chronic myelogenous leukemia, whose SHP-1 mRNA levels were significantly lower in case of IMA treatment failure (P < .0001). In conclusion, we suggest that SHP-1 could be a new biologic indicator at baseline of IMA sensitivity in patients with chronic myelogenous leukemia.
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Irino T, Uemura M, Yamane H, Umemura S, Utsumi T, Kakazu N, Shirakawa T, Ito M, Suzuki T, Kinoshita K. JAK2 V617F-dependent upregulation of PU.1 expression in the peripheral blood of myeloproliferative neoplasm patients. PLoS One 2011; 6:e22148. [PMID: 21789226 PMCID: PMC3138766 DOI: 10.1371/journal.pone.0022148] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2010] [Accepted: 06/20/2011] [Indexed: 01/28/2023] Open
Abstract
Myeloproliferative neoplasms (MPN) are multiple disease entities characterized by clonal expansion of one or more of the myeloid lineages (i.e. granulocytic, erythroid, megakaryocytic and mast cell). JAK2 mutations, such as the common V617F substitution and the less common exon 12 mutations, are frequently detected in such tumor cells and have been incorporated into the diagnostic criteria published by the World Health Organization since 2008. However, the mechanism by which these mutations contribute to MPN development is poorly understood. We examined gene expression profiles of MPN patients focusing on genes in the JAK–STAT signaling pathway using low-density real-time PCR arrays. We identified the following 2 upregulated genes in MPN patients: a known target of the JAK–STAT axis, SOCS3, and a potentially novel target, SPI1, encoding PU.1. Induction of PU.1 expression by JAK2 V617F in JAK2-wildtype K562 cells and its downregulation by JAK2 siRNA transfection in JAK2 V617F-positive HEL cells supported this possibility. We also found that the ABL1 kinase inhibitor imatinib was very effective in suppressing PU.1 expression in BCR-ABL1-positive K562 cells but not in HEL cells. This suggests that PU.1 expression is regulated by both JAK2 and ABL1. The contribution of the two kinases in driving PU.1 expression was dominant for JAK2 and ABL1 in HEL and K562 cells, respectively. Therefore, PU.1 may be a common transcription factor upregulated in MPN. PU.1 is a transcription factor required for myeloid differentiation and is implicated in erythroid leukemia. Therefore, expression of PU.1 downstream of activated JAK2 may explain why JAK2 mutations are frequently observed in MPN patients.
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Affiliation(s)
- Tamotsu Irino
- Shiga Medical Center for Adults, Moriyama, Japan
- Division of Medical Biophysics, Kobe University Graduate School of Health Science, Kobe, Japan
| | | | - Humitsugu Yamane
- Department of Environmental and Preventive Medicine, Shimane University School of Medicine, Izumo, Japan
| | | | | | - Naoki Kakazu
- Department of Environmental and Preventive Medicine, Shimane University School of Medicine, Izumo, Japan
| | - Taku Shirakawa
- Division of Medical Biophysics, Kobe University Graduate School of Health Science, Kobe, Japan
| | - Mitsuhiro Ito
- Division of Medical Biophysics, Kobe University Graduate School of Health Science, Kobe, Japan
| | | | - Kazuo Kinoshita
- Shiga Medical Center Research Institute, Moriyama, Japan
- * E-mail:
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56
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Redig AJ, Vakana E, Platanias LC. Regulation of mammalian target of rapamycin and mitogen activated protein kinase pathways by BCR-ABL. Leuk Lymphoma 2011; 52 Suppl 1:45-53. [PMID: 21299459 DOI: 10.3109/10428194.2010.546919] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A large body of evidence has established that BCR-ABL regulates engagement and activation of mammalian target of rapamycin (mTOR) and mitogen activated protein kinase (MAPK) signaling cascades. mTOR-mediated signals, as well as signals transduced by ERK, JNK, and p38 MAPK, are important components of the aberrant signaling induced by BCR-ABL. Such deregulation of mTOR or MAPK pathways contributes to BCR-ABL leukemogenesis, and their targeting with selective inhibitors provides an approach to enhance antileukemic responses and/or overcome leukemic cell resistance in chronic myeloid leukemia (CML) and Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukemia (ALL). This review explores recent advances in our understanding of mTOR and MAPK signaling in BCR-ABL-expressing leukemias and discusses the potential therapeutic targeting of these pathways in CML and Ph+ ALL.
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Affiliation(s)
- Amanda J Redig
- Robert H. Lurie Comprehensive Cancer Center and Division of Hematology/Oncology, Northwestern University Medical School and Jesse Brown VA Medical Center, Chicago, IL, USA
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57
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Perrotti D, Harb JG. BCR-ABL1 kinase-dependent alteration of mRNA metabolism: potential alternatives for therapeutic intervention. Leuk Lymphoma 2011; 52 Suppl 1:30-44. [PMID: 21299458 DOI: 10.3109/10428194.2010.546914] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The use of first- and second-generation tyrosine kinase inhibitors (TKIs) significantly improves prognosis for patients with early chronic phase chronic myeloid leukemia (CML) and efficiently counteracts leukemia in most patients with CML bearing a disease characterized by the expression of BCR-ABL1 mutants. However, the so-called 'tinib' TKIs (e.g. imatinib, nilotinib, dasatinib, and bosutinib) are both ineffective in patients who undergo blastic transformation and unable to eradicate CML at the stem cell level. This raises a few important questions. Is BCR-ABL1 expression and/or activity essential for blastic transformation? Is blastic transformation the result of genetic or epigenetic events that occur at the stem cell level which only become apparent in the granulocyte-macrophage progenitor (GMP) cell pool, or does it arise directly at the GMP level? As altered mRNA metabolism contributes to the phenotype of blast crisis CML progenitors (decreased translation of tumor suppressor genes and transcription factors essential for terminal differentiation and increased translation of anti-apoptotic genes), one attractive concept is to restore levels of these essential molecules to their normal levels. In this review, we discuss the mechanisms by which mRNA processing, translation, and degradation are deregulated in BCR-ABL1 myeloid blast crisis CML progenitors, and present encouraging results from studies with pharmacologic inhibitors which support their inclusion in the clinic.
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Affiliation(s)
- Danilo Perrotti
- Human Cancer Genetics Program, Depatment of Molecular Virology, Immunology and Medical Genetics, Comprehensive Cancer Center and Center for RNA Biology, The Ohio State University, Columbus, OH 43210-2207, USA.
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Abstract
Despite the success of imatinib mesylate (IM) in the early chronic phase of chronic myeloid leukemia (CML), patients are resistant to IM and other kinase inhibitors in the later stages of CML. Our findings indicate that inhibition of Janus kinase 2 (Jak2) in Bcr–Abl+ cells overcomes IM resistance although the precise mechanism of Jak2 action is unknown. Knocking down Jak2 in Bcr–Abl+ cells reduced levels of the Bcr–Abl protein and also the phosphorylation of Tyr177 of Bcr–Abl, and Jak2 overexpression rescued these knockdown effects. Treatment of Bcr–Abl+ cells with Jak2 inhibitors for 4–6 h but not with IM also reduced Bcr–Abl protein and pTyr177 levels. In vitro kinase experiments performed with recombinant Jak2 showed that Jak2 readily phosphorylated Tyr177 of Bcr–Abl (a Jak2 consensus site, YvnV) whereas c-Abl did not. Importantly, Jak2 inhibition decreased pTyr177 Bcr–Abl in immune complexes but did not reduce levels of Bcr–Abl, suggesting that the reduction of Bcr–Abl by Jak2 inhibition is a separate event from phosphorylation of Tyr177. Jak2 inhibition by chemical inhibitors (TG101209/WP1193) and Jak2 knockdown diminished the activation of Ras, PI-3 kinase pathways and reduced levels of pTyrSTAT5. These findings suggest that Bcr–Abl stability and oncogenic signaling in CML cells are under the control of Jak2.
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59
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Chang WL, Chang CS, Chiang PC, Ho YF, Liu JF, Chang KW, Guh JH. 2-Phenyl-5-(pyrrolidin-1-yl)-1-(3,4,5-trimethoxybenzyl)-1H-benzimidazole, a benzimidazole derivative, inhibits growth of human prostate cancer cells by affecting tubulin and c-Jun N-terminal kinase. Br J Pharmacol 2010; 160:1677-89. [PMID: 20649571 DOI: 10.1111/j.1476-5381.2010.00832.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND AND PURPOSE The c-Jun N-terminal kinase (JNK) and tubulin are, frequently, targets for developing anti-cancer drugs. A major obstacle to successful development is P-glycoprotein (P-gp)-mediated resistance. Here, we have assessed a compound that inhibited growth of cancer cells, for effects on JNK and tubulin and as a substrate for P-gp. EXPERIMENTAL APPROACH Several pharmacological and biochemical assays were used to characterize signalling pathways of 2-phenyl-5-(pyrrolidin-1-yl)-1-(3,4,5-trimethoxybenzyl)-1H-benzimidazole (PPTMB), a benzimidazole analogue, in prostate cancer cells. KEY RESULTS PPTMB inhibited proliferation of several human prostate cancer cell lines. It displayed similar activity against a P-gp-rich cell line, indicating that PPTMB was not a substrate for P-gp. PPTMB induced G2/M arrest of the cell cycle and subsequent apoptosis, using flow cytometry. Tubulin polymerization assays and Western blot analysis showed that PPTMB directly acted on tubulin and caused disruption of microtubule dynamics, inducing mitotic arrest and sustained high levels of cyclin B1 expression and Cdk1 activation. Subsequently, mitochondria-related apoptotic cascades were induced, including Bcl-2 and Bcl-xL phosphorylation, Mcl-1 down-regulation, truncated Bad formation and activation of caspase-9 and -3. PPTMB stimulated JNK phosphorylation at Thr(183)/Tyr(185). SP600125, a specific JNK inhibitor, significantly inhibited apoptotic signalling, indicating that JNK plays a key role in PPTMB action. PPTMB showed a 10-fold higher potency against prostate cancer cells than normal prostate cells. CONCLUSIONS AND IMPLICATIONS PPTMB is an effective anti-cancer agent. It disrupted microtubule dynamics, leading to mitotic arrest of the cell cycle and JNK activation, which in turn stimulated the mitochondria-related apoptotic cascades in prostate cancer cells.
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Affiliation(s)
- Wei-Ling Chang
- School of Pharmacy, National Taiwan University, Taipei, Taiwan
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60
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Ma LD, Zhou M, Wen SH, Ni C, Jiang LJ, Fan J, Xia L. Effects of STAT3 silencing on fate of chronic myelogenous leukemia K562 cells. Leuk Lymphoma 2010; 51:1326-36. [PMID: 20497005 DOI: 10.3109/10428194.2010.483748] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Signal transducer and activator of transcription 3 (STAT3), a transcription factor, is constitutively activated in various types of cancers. Previous investigations have demonstrated that this overexpression of STAT3 in human malignancies plays important roles in maintaining the characteristics of malignant tumors by having an effect on proliferation, differentiation, and/or immortalization. Thus, inhibition of STAT3 expression could be a potent therapeutic approach in cancer treatment. In this study, we introduced STAT3 siRNA into the human chronic myelogenous leukemia (CML) K562 cell line, which has constitutive activation of STAT3, to elucidate the role of STAT3 in CML. The cells were transducted with STAT3 siRNA using lentivirus. FACS, real-time PCR, and Western blot were used to study changes in STAT3 expression levels in transducted cells by comparing with negative control siRNA lentivirus transduction. Knockdown of STAT3 by STAT3 siRNA caused a decrease in STAT3 protein level, inhibition of growth and proliferation, cell cycle blockade, visible morphologic changes, and induction of apoptosis in K562 cells. These findings demonstrate that STAT3 does indeed play a critical role in the survival of K562 cells, which may have potential application in designing molecular therapies for CML treatment.
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Affiliation(s)
- Ling-di Ma
- Center Laboratory, Second Changzhou People's Hospital, Affiliated Hospital of Nanjing Medical University, Changzhou, China.
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61
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Lai SY, Johnson FM. Defining the role of the JAK-STAT pathway in head and neck and thoracic malignancies: implications for future therapeutic approaches. Drug Resist Updat 2010; 13:67-78. [PMID: 20471303 DOI: 10.1016/j.drup.2010.04.001] [Citation(s) in RCA: 132] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2010] [Accepted: 04/06/2010] [Indexed: 12/17/2022]
Abstract
Although the role of the Janus kinase (JAK)-signal transducer and activator of transcription (STAT) pathway has been most extensively studied in hematopoietic cells and hematologic malignancies, it is also activated in epithelial tumors, including those originating in the lungs and head and neck. The canonical pathway involves the activation of JAK following ligand binding to cytokine receptors. The activated JAKs then phosphorylate STAT proteins, leading to their dimerization and translocation into the nucleus. In the nucleus, STATs act as transcription factors with pleiotropic downstream effects. STATs can be activated independently of JAKs, most notably by c-Src kinases. In cancer cells, STAT3 and STAT5 activation leads to the increased expression of downstream target genes, leading to increased cell proliferation, cell survival, angiogenesis, and immune system evasion. STAT3 and STAT5 are expressed and activated in head and neck squamous cell carcinoma (HNSCC) where they contribute to cell survival and proliferation. In HNSCC, STATs can be activated by a number of signal transduction pathways, including the epidermal growth factor receptor (EGFR), alpha7 nicotinic receptor, interleukin (IL) receptor, and erythropoietin receptor pathways. Activated STATs are also expressed in lung cancer, but the biological effects of JAK/STAT inhibition in this cancer are variable. In lung cancer, STAT3 can be activated by multiple pathways, including EGFR. Several approaches have been used to inhibit STAT3 in the hopes of developing an antitumor agent. Although several STAT3-specific agents are promising, none are in clinical development, mostly because of drug delivery and stability issues. In contrast, several JAK inhibitors are in clinical development. These orally available, ATP-competitive, small-molecule kinase inhibitors are being tested in myeloproliferative disorders. Future studies will determine whether JAK inhibitors are useful in the treatment of HNSCC or lung cancer.
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Affiliation(s)
- Stephen Y Lai
- Department of Head and Neck Surgery, The University of Texas M.D. Anderson Cancer Center at Houston, Houston, TX 77030, USA
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Zhang MX, Zhao X, Wang ZG, Zhao WM, Wang YS. Constitutive activation of signal transducer and activator of transcription 3 regulates expression of vascular endothelial growth factor in human meningioma differentiation. J Cancer Res Clin Oncol 2010; 136:981-8. [PMID: 20052595 PMCID: PMC2874489 DOI: 10.1007/s00432-009-0743-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2009] [Accepted: 11/24/2009] [Indexed: 02/07/2023]
Abstract
Purpose Janus tyrosine kinases (JAKs) and signal transducer and activator of transcription factors (STATs), especially STAT3, are constitutively activated in human cancers. The function of STAT3 in the pathogenesis of meningioma remains unknown. In this study, we investigated the role of JAK1/STAT3 regulating vascular endothelial growth factor (VEGF) expression in the occurrence and progression of human meningioma. Methods We detected the expression of JAK1, p-JAK1, STAT3, p-STAT3, and VEGF in human meningioma and normal dura tissues by RT–PCR, Western blot analysis, and immunohistochemistry. Results JAK1, p-JAK1, STAT3, p-STAT3, and VEGF showed high expression in grade I and grade II meningioma. The level of STAT3 activation was associated with VEGF expression; all meningioma tumors that expressed p-STAT3 also expressed VEGF. Both frequency of positivity and expression were enhanced with increasing tumor grade; high frequencies and levels were found in grade II tumors, with no expression detected in normal dura tissues (P < 0.05). Conclusions VEGF is directly regulated by constitutive STAT3 activity and associated with meningioma differentiation. STAT3 has an important role in the occurrence and development of human meningioma by regulating VEGF expression.
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Affiliation(s)
- Mao Xiu Zhang
- Department of Microbiology, Shandong University School of Medicine, 44#, Wenhua Xi Road, 250012 Jinan, Shandong, People's Republic of China
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63
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Dominis M. Significance of nanoscale technology in identification of biological response to therapy. Future Oncol 2009; 5:945-7. [PMID: 19792963 DOI: 10.2217/fon.09.76] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Evaluation of: Fan AC, Deb-Basu D, Orban MW et al.: Nanofluidic proteomic assay for serial analysis of oncoprotein activation in clinical specimens. Nat. Med. 15, 566–571 (2009). In order to detect oncoprotein expression and phosphorylation in a small amount of cells, the authors developed a nanofluidic proteomic immunoassay. Several different settings were tested. This method showed results in protein detection comparable with western blot in both in vitro and in vivo experiments. It was demonstrated that the nanofluidic proteomic immunoassay can be used for assessment of protein phosphorylation changes, and thus could be useful for therapy monitoring. Detection of protein isoforms was also carried out for in vitro and in vivo settings. In conclusion, a method that combines isoelectric focusing of proteins and antibody detection of specific targets with chemiluminescence is applicable in many preclinical trials, as well as for the monitoring of disease treatment in practice.
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Affiliation(s)
- Mara Dominis
- Institute of Pathology and Cytology, University Hospital Merkur, 10 000 Zagreb, Croatia.
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64
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Short-term regulation of organic anion transporters. Pharmacol Ther 2009; 125:55-61. [PMID: 19744520 DOI: 10.1016/j.pharmthera.2009.08.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2009] [Accepted: 08/19/2009] [Indexed: 12/19/2022]
Abstract
Organic anion transporters (OATs), which belong to the superfamily SLC22A, are key determinants in the absorption, distribution, and excretion of a diverse array of environmental toxins, and clinically important drugs, and, therefore, are critical for the survival of mammalian species. Alteration in the function of these drug transporters plays important roles in intra- and inter-individual variability of the therapeutic efficacy and the toxicity of many drugs. As a result, the activity of OATs must be under tight regulation so as to carry out their normal functions. This review article highlights the recent advances from our laboratory as well as from others in delineating the short-term regulation of OATs. These advances provide important insights into strategies to maximize therapeutic efficacy in drug development.
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65
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LLL-3, a STAT3 inhibitor, represses BCR-ABL-positive cell proliferation, activates apoptosis and improves the effects of Imatinib mesylate. Cancer Chemother Pharmacol 2009; 65:1039-46. [PMID: 19701750 DOI: 10.1007/s00280-009-1109-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2009] [Accepted: 08/07/2009] [Indexed: 10/20/2022]
Abstract
PURPOSE The chimeric protein BCR-ABL, a constitutively active protein-tyrosine kinase, triggers downstream signalling proteins, such as STAT3, ultimately resulting in the survival of myeloid progenitors in BCR-ABL-positive leukemias. Here, we evaluated the effect of LLL-3, an inhibitor of STAT3 activity, on cell viability and its addictive effects with Imatinib mesylate (IM) treatment in BCR-ABL-positive cells. METHODS Viability of cell lines was determined using the WST-1 assay in response to drug treatment, either LLL-3 alone or in conjunction with IM. Annexin V-FITC/PI staining, sub-G1 DNA content and Caspase-3/7 activation assays were performed to evaluate apoptosis. RESULTS LLL-3 treatment decreased cell viability, triggered apoptosis and activated Caspases-3/7 in K562 cells. LLL-3 increases IM treatment to inhibited cell viability and activation of apoptosis in BCR-ABL-positive cell lines. CONCLUSIONS LLL-3 reduced cell viability and induced apoptosis in K562 cells. Moreover, the observed addictive effects of co-treatment with IM and LLL-3 suggest this combination has therapeutic potential.
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66
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Zhang WW, Cortes JE, Yao H, Zhang L, Reddy NG, Jabbour E, Kantarjian HM, Jones D. Predictors of primary imatinib resistance in chronic myelogenous leukemia are distinct from those in secondary imatinib resistance. J Clin Oncol 2009; 27:3642-9. [PMID: 19506164 DOI: 10.1200/jco.2008.19.4076] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
PURPOSE A subset of patients with chronic myelogenous leukemia (CML) do not respond to the tyrosine kinase inhibitor (TKI) imatinib mesylate. Such primary imatinib resistance is distinguished from secondary resistance which reemerges after attainment of cytogenetic remission. PATIENTS AND METHODS We studied gene expression patterns in total WBCs using a panel of 21 genes previously implicated in TKI handling, resistance, or progression comparing patients who had newly diagnosed TKI-naive CML that had optimal (n = 41), or suboptimal (n = 7) responses to imatinib, or primary resistance (n = 20). Expression patterns were compared to those in secondary TKI-resistant chronic phase CML without ABL1 kinase domain mutations (n = 29), and to lymphoid (n = 15) or myeloid blast phase disease (n = 12). RESULTS Fifteen genes in the panel distinguished blast phase from chronic phase disease, and 12 genes distinguished newly diagnosed CML from TKI-resistant CML without ABL1 kinase domain mutations, but only a single gene, prostaglandin-endoperoxide synthase 1/cyclooxgenase 1 (PTGS1/COX1; P = .005), differentiated imatinib-responsive from primary imatinib-resistant CML. The association of primary imatinib resistance with higher transcript levels of the drug metabolism gene PTGS1 was confirmed in a separate data set of 68 newly diagnosed, imatinib-treated CML (P = .008). In contrast, up to 11 different genes were identified in a multivariate model that optimally discriminated secondary imatinib resistance lacking ABL1 kinase domain mutation from imatinib-responsive cases, likely related to the more complex pathogenesis of secondary resistance. CONCLUSION Gene expression profiling of CML at diagnosis for PTGS1 may be useful in predicting imatinib response and in selecting alternate therapy.
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Affiliation(s)
- Wenyong W Zhang
- Department of Pathology, Baylor College of Medicine, Houston TX, USA
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Defective homing and impaired induction of cytotoxic T cells by BCR/ABL-expressing dendritic cells. Blood 2009; 113:4681-9. [DOI: 10.1182/blood-2008-05-156471] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Abstract
Chronic myelogenous leukemia (CML) is a malignant myeloproliferative disease arising from a hematopoietic stem cell expressing the BCR/ABL fusion protein. Leukemic and dendritic cells (DCs) develop from the same transformed hematopoietic progenitors. How BCR/ABL interferes with the immunoregulatory function of DCs in vivo is unknown. We analyzed the function of BCR/ABL-expressing DCs in a retroviral-induced murine CML model using the glycoprotein of lymphocytic choriomeningitis virus as a model leukemia antigen. BCR/ABL-expressing DCs were found in bone marrow, thymus, spleen, lymph nodes, and blood of CML mice. They were characterized by a low maturation status and induced only limited expansion of naive and memory cytotoxic T lymphocytes (CTLs). In addition, immunization with in vitro–generated BCR/ABL-expressing DCs induced lower frequencies of specific CTLs than immunization with control DCs. BCR/ABL-expressing DCs preferentially homed to the thymus, whereas only few BCR/ABL-expressing DCs reached the spleen. Our results indicate that BCR/ABL-expressing DCs do not efficiently induce CML-specific T-cell responses resulting from low DC maturation and impaired homing to secondary lymphoid organs. In addition, BCR/ABL-expressing DCs in the thymus may contribute to CML-specific tolerance induction of specific CTLs.
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Bixby D, Talpaz M. Mechanisms of resistance to tyrosine kinase inhibitors in chronic myeloid leukemia and recent therapeutic strategies to overcome resistance. HEMATOLOGY. AMERICAN SOCIETY OF HEMATOLOGY. EDUCATION PROGRAM 2009; 2009:461-476. [PMID: 20008232 DOI: 10.1182/asheducation-2009.1.461] [Citation(s) in RCA: 126] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Given its relative rarity, it may at first seem surprising that chronic myeloid leukemia (CML) has garnered so much attention over the last decade. Yet, the advances in molecular pathogenesis that have been derived from studying this leukemia have clearly benefited all of oncology. Moreover, the strides in drug design and development that have also ensued around CML have given rise to what others have called a molecular revolution in cancer therapy. While a majority of patients with chronic phase CML (CP-CML) have an excellent durable response to imatinib (Gleevec, Novartis, Basel, Switzerland), a clear minority will unfortunately have signs of primary or secondary resistance to therapy. Significant efforts geared toward understanding the molecular mechanisms of imatinib resistance have yielded valuable insights into the biology of drug trafficking into and out of cells, epigenetic control of cellular processes, alterations in enzymatic structures, and the rational structural-based design of small molecule enzyme inhibitors. This review will describe the efforts at understanding the pathogenesis of imatinib resistance and the molecular rationale for the development of second- and now third-generation therapies for patients with CML.
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MESH Headings
- Antineoplastic Agents/administration & dosage
- Antineoplastic Agents/pharmacokinetics
- Antineoplastic Agents/pharmacology
- Antineoplastic Agents/therapeutic use
- Benzamides
- Biological Transport/drug effects
- Dose-Response Relationship, Drug
- Drug Delivery Systems
- Drug Design
- Drug Resistance, Neoplasm/drug effects
- Drugs, Investigational/pharmacology
- Drugs, Investigational/therapeutic use
- Epigenesis, Genetic
- Fusion Proteins, bcr-abl/antagonists & inhibitors
- Fusion Proteins, bcr-abl/genetics
- Fusion Proteins, bcr-abl/physiology
- Humans
- Imatinib Mesylate
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/drug therapy
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/enzymology
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics
- Neoplasm Proteins/antagonists & inhibitors
- Neoplasm Proteins/genetics
- Neoplasm Proteins/physiology
- Piperazines/administration & dosage
- Piperazines/pharmacokinetics
- Piperazines/pharmacology
- Piperazines/therapeutic use
- Protein Kinase Inhibitors/administration & dosage
- Protein Kinase Inhibitors/classification
- Protein Kinase Inhibitors/pharmacokinetics
- Protein Kinase Inhibitors/pharmacology
- Protein Kinase Inhibitors/therapeutic use
- Protein-Tyrosine Kinases/antagonists & inhibitors
- Pyrimidines/administration & dosage
- Pyrimidines/pharmacokinetics
- Pyrimidines/pharmacology
- Pyrimidines/therapeutic use
- Salvage Therapy
- Signal Transduction/drug effects
- Signal Transduction/genetics
- Signal Transduction/physiology
- Structure-Activity Relationship
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Affiliation(s)
- Dale Bixby
- Division of Hematology and Oncology, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
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69
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Wang W, Edington HD, Jukic DM, Rao UNM, Land SR, Kirkwood JM. Impact of IFNalpha2b upon pSTAT3 and the MEK/ERK MAPK pathway in melanoma. Cancer Immunol Immunother 2008; 57:1315-21. [PMID: 18386001 PMCID: PMC11030104 DOI: 10.1007/s00262-008-0466-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2007] [Accepted: 01/28/2008] [Indexed: 12/12/2022]
Abstract
PURPOSE High-dose IFNalpha2b (HDI) was established as the first effective adjuvant therapy for patients with high-risk resected melanoma more than a decade ago, but its fundamental molecular mechanism of action remains unclear. STAT3 and the mitogen activated protein kinases (MAPKs), especially ERK (extracellular signal-regulating kinase) and MEK (MAPK/ERK kinase), play roles in melanoma progression and host immunity. We have therefore evaluated STAT3 and MEK/ERK MAP kinases in patients with regional lymph node metastasis (stage IIIB) of melanoma in the context of a prospective neoadjuvant trial of HDI (UPCI 00-008). PATIENTS AND METHODS In the context of this trial, HDI was administered daily for 20 doses following diagnostic biopsy, and prior to definitive surgery. Immunohistochemistry for pSTAT3, phospho-MEK1/2, phospho-ERK1/2, and EGFR was performed on paired fixed (nine patients) biopsies. RESULTS HDI was found to down-regulate pSTAT3 (P = 0.008) and phospho-MEK1/2 (P = 0.008) levels significantly in tumor cells. Phospho-ERK1/2 was down-regulated by HDI in tumor cells (P = 0.015), but not in lymphoid cells. HDI down-regulated EGFR (P = 0.013), but pSTAT3 activation appeared not to be associated with EGFR expression and the MEK/ERK MAPK pathway. CONCLUSION We conclude that HDI regulates MAPK signaling differentially in melanoma tumor cells and host lymphoid cells in vivo. STAT3 activation is independent of the EGFR/MEK/ERK signaling pathway.
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Affiliation(s)
- Wenjun Wang
- Department of Medicine, Division of Hematology/Oncology, University of Pittsburgh, Hillman Cancer Center, Research Pavilion, Suite 1.32, 5117 Centre Avenue, Pittsburgh, PA 15213-2584 USA
- Melanoma and Skin Cancer Program, University of Pittsburgh Cancer Institute, Hillman Cancer Center, Research Pavilion, Suite 1.32, 5117 Centre Avenue, Pittsburgh, PA 15213-2584 USA
| | | | - Drazen M. Jukic
- Department of Dermatology, University of Pittsburgh Medical Center, Pittsburgh, PA USA
- Department of Pathology, University of Pittsburgh Medical Center, Pittsburgh, PA USA
| | - Uma N. M. Rao
- Department of Pathology, University of Pittsburgh Medical Center, Pittsburgh, PA USA
| | - Stephanie R. Land
- Department of Biostatistics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA USA
| | - John M. Kirkwood
- Department of Medicine, Division of Hematology/Oncology, University of Pittsburgh, Hillman Cancer Center, Research Pavilion, Suite 1.32, 5117 Centre Avenue, Pittsburgh, PA 15213-2584 USA
- Melanoma and Skin Cancer Program, University of Pittsburgh Cancer Institute, Hillman Cancer Center, Research Pavilion, Suite 1.32, 5117 Centre Avenue, Pittsburgh, PA 15213-2584 USA
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70
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Abstract
Pluripotent ES (embryonic stem) cells can be expanded in culture and induced to differentiate into a wide range of cell types. Self-renewal of ES cells involves proliferation with concomitant suppression of differentiation. Some critical and conserved pathways regulating self-renewal in both human and mouse ES cells have been identified, but there is also evidence suggesting significant species differences. Cytoplasmic and receptor tyrosine kinases play important roles in proliferation, survival, self-renewal and differentiation in stem, progenitor and adult cells. The present review focuses on the role of tyrosine kinase signalling for maintenance of the undifferentiated state, proliferation, survival and early differentiation of ES cells.
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Affiliation(s)
- Cecilia Annerén
- Department of Medical Biochemistry and Microbiology, Biomedical Center, Uppsala University, 751 23 Uppsala, Sweden
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71
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Katsoulidis E, Sassano A, Majchrzak-Kita B, Carayol N, Yoon P, Jordan A, Druker BJ, Fish EN, Platanias LC. Suppression of interferon (IFN)-inducible genes and IFN-mediated functional responses in BCR-ABL-expressing cells. J Biol Chem 2008; 283:10793-803. [PMID: 18287094 PMCID: PMC2447623 DOI: 10.1074/jbc.m706816200] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2007] [Revised: 01/31/2008] [Indexed: 01/12/2023] Open
Abstract
The interferons (IFNs) are cytokines that play key roles in host defense against viral infections and immune surveillance against cancer. We report that BCR-ABL transformation of hematopoietic cells results in suppression of IFN-dependent responses, including transcription of IFN-inducible genes and generation of IFN-mediated antiviral effects. BCR-ABL transformation suppresses expression of several IFN-regulated genes containing IFN-sensitive response element (ISRE) or GAS elements in their promoters, including Isg15, Irf1, Irf9, and Ifit2 (interferon-induced protein with tetratricopeptide repeats 2). Suppression of transcription of ISRE-containing genes is also seen in cells expressing various BCR-ABL kinase domain mutants, including T315I, H396P, Y253F, and E255K, but not kinase-defective BCR-ABL. Such effects are associated with impaired IFN-dependent phosphorylation of Stat1 on Tyr(701) and Stat3 on Tyr(705) and defective binding of Stat complexes to ISRE or GAS elements. Beyond suppression of Stat activities, BCR-ABL inhibits IFN-inducible phosphorylation/activation of the p38 MAPK, suggesting a dual mechanism by which this abnormal fusion protein blocks IFN transcriptional responses. The inhibitory activities of BCR-ABL ultimately result in impaired IFNalpha-mediated protection against encephalomyocarditis virus infection and reversal of IFN-dependent growth suppression. Altogether, our data provide evidence for a novel mechanism by which BCR-ABL impairs host defenses and promotes malignant transformation, involving dual suppression of IFN-activated signaling pathways.
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Affiliation(s)
- Efstratios Katsoulidis
- Robert H. Lurie Comprehensive Cancer Center and Division of Hematology-Oncology, Northwestern University Medical School and Lakeside Veterans Affairs Medical Center, Chicago, Illinois 60611, USA
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72
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Krajewska M, Banares S, Zhang EE, Huang X, Scadeng M, Jhala US, Feng GS, Krajewski S. Development of diabesity in mice with neuronal deletion of Shp2 tyrosine phosphatase. THE AMERICAN JOURNAL OF PATHOLOGY 2008; 172:1312-24. [PMID: 18403587 DOI: 10.2353/ajpath.2008.070594] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Obesity and diabetes, termed "diabesity," are serious health problems that are increasing in frequency. However, the molecular mechanisms and neuronal regulation of these metabolic disorders are not fully understood. We show here that Shp2, a widely expressed Src homology 2-containing Tyr phosphatase, plays a critical role in the adult brain to control food intake, energy balance, and metabolism. Mice with a neuron-specific, conditional Shp2 deletion were generated by crossing a pan-neuronal Cre-line (CRE3) with Shp2(flox/flox) mice. These congenic mice, CRE3/Shp2-KO, developed obesity and diabetes and the associated pathophysiological complications that resemble those encountered in humans, including hyperglycemia, hyperinsulinemia, hyperleptinemia, insulin and leptin resistance, vasculitis, diabetic nephropathy, urinary bladder infections, prostatitis, gastric paresis, and impaired spermatogenesis. This mouse model may help to elucidate the molecular mechanisms that lead to the development of diabesity in humans and provide a tool to study the in vivo complications of uncontrolled diabetes.
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Affiliation(s)
- Maryla Krajewska
- Burnham Institute for Medical Research, University of California San Diego, La Jolla, CA 92037, USA
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73
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STAT3 as a target for inducing apoptosis in solid and hematological tumors. Cell Res 2008; 18:254-67. [PMID: 18227858 DOI: 10.1038/cr.2008.18] [Citation(s) in RCA: 387] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Studies in the past few years have provided compelling evidence for the critical role of aberrant Signal Transducer and Activator of Transcription 3 (STAT3) in malignant transformation and tumorigenesis. Thus, it is now generally accepted that STAT3 is one of the critical players in human cancer formation and represents a valid target for novel anticancer drug design. This review focuses on aberrant STAT3 and its role in promoting tumor cell survival and supporting the malignant phenotype. A brief evaluation of the current strategies targeting STAT3 for the development of novel anticancer agents against human tumors harboring constitutively active STAT3 will also be presented.
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74
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Tsyrulnyk A, Moriggl R. A detailed protocol for bacterial artificial chromosome recombineering to study essential genes in stem cells. Methods Mol Biol 2008; 430:269-93. [PMID: 18370306 DOI: 10.1007/978-1-59745-182-6_19] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Bacterial artificial chromosome (BAC) recombineering is a novel technique for DNA manipulation. It starts from an original chromosomal gene locus that is modified to introduce a transgene under the expression control of the original gene locus. In most cases a cell type specific promoter is chosen and the transgene is placed in a way that the exon containing the start codon is replaced. Alternatively, BACs such as the Rosa26 BAC are chosen because of their known open chromatin and ubiquitous promoter activity that allows a broad expression profile of the transgene in the whole body. Thus, transgenes can be overexpressed within their natural transcriptional regulatory circuit. BAC transgenes have a high tendency to maintain their appropriate chromatin status because the endogenous locus was expressed in different cell types. Here, we give a detailed protocol based on the original idea to choose a BAC approach until the injection of the modified BAC DNA that leads to the generation of novel transgenic mouse lines. As an example for a BAC mouse model suitable for the analysis of stem cell or hematopoietic stem cell functions, we chose modification of the locus for the transcription factor Stat3. Stat3 variants replace the wild-type Stat3 gene to study their function in particular in the earliest cell types of the body.
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75
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Kim YK, Shin MG, Kim HR, Yang DH, Cho SH, Lee JJ, Chung IJ, Ryang DW, Kim HJ. Simultaneous occurrence of the JAK2V617F mutation and BCR-ABL gene rearrangement in patients with chronic myeloproliferative disorders. Leuk Res 2007; 32:993-5. [PMID: 18055011 DOI: 10.1016/j.leukres.2007.10.018] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2007] [Revised: 10/23/2007] [Accepted: 10/25/2007] [Indexed: 11/16/2022]
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Sakamoto A, Matono H, Yoshida T, Tanaka K, Matsuda S, Oda Y, Iwamoto Y. Dedifferentiated liposarcoma with leukocytosis. A case report of G-CSF-producing soft-tissue tumors, possible association with undifferentiated liposarcoma lineage. World J Surg Oncol 2007; 5:131. [PMID: 18021394 PMCID: PMC2203997 DOI: 10.1186/1477-7819-5-131] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2007] [Accepted: 11/16/2007] [Indexed: 11/26/2022] Open
Abstract
Background Granulocyte-colony-stimulating factor (G-CSF) functions as a hematopoietic growth factor and it is responsible for leukocytosis. G-CSF-producing tumors associated with leukocytosis include various types of malignancies. Case presentation We report the case of a 72-year-old man with dedifferentiated liposarcoma characterized by dedifferentiated components of malignant fibrous histiocytoma (MFH)-like features in addition to well-differentiated lipoma-like liposarcoma, arising from his upper arm. Preoperative laboratory data showed leukocytosis (103,700/μl). The serum level of G-CSF was also elevated (620 pg/ml [normal, <8 pg/ml]). Nine days after the surgery, the leukocytosis was relieved (WBC; 6,920/μl) and the elevated serum G-CSF level was significantly decreased (G-CSF; 12 pg/ml). One month after the surgery, leukocytosis gradually began to appear again. Three months after the surgery metastatic lung lesions were confirmed, and the patient subsequently died of respiratory problems. In the English literature regarding soft-tissue tumors with leukocytosis, including the current case, we could review a total of 6 cases of liposarcoma with leukocytosis. The subtype of these 6 liposarcoma cases was undifferentiated liposarcoma, comprising dedifferentiated liposarcoma in 4 cases and pleomorphic liposarcoma in 2 cases. Conclusion Since the only other soft-tissue tumor that was associated with leukocytosis was MFH, and since MFH is characterized by the absence of any specific differentiation, we would like to propose a possible association between G-CSF-producing soft-tissue tumors and an undifferentiated liposarcoma lineage, such as dedifferentiated liposarcoma or pleomorphic liposarcoma.
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Affiliation(s)
- Akio Sakamoto
- Department of Orthopedic Surgery, Graduate School of Medical Sciences, Kyushu University, Fukuoka, 812-8582, Japan.
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77
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Identification of novel posttranscriptional targets of the BCR/ABL oncoprotein by ribonomics: requirement of E2F3 for BCR/ABL leukemogenesis. Blood 2007; 111:816-28. [PMID: 17925491 DOI: 10.1182/blood-2007-05-090472] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Several RNA binding proteins (RBPs) have been implicated in the progression of chronic myelogenous leukemia (CML) from the indolent chronic phase to the aggressively fatal blast crisis. In the latter phase, expression and function of specific RBPs are aberrantly regulated at transcriptional or posttranslational levels by the constitutive kinase activity of the BCR/ABL oncoprotein. As a result, altered expression/function of RBPs leads to increased resistance to apoptotic stimuli, enhanced survival, growth advantage, and differentiation arrest of CD34+ progenitors from patients in CML blast crisis. Here, we identify the mRNAs bound to the hnRNP-A1, hnRNP-E2, hnRNP-K, and La/SSB RBPs in BCR/ABLtransformed myeloid cells. Interestingly, we found that the mRNA encoding the transcription factor E2F3 associates to hnRNP-A1 through a conserved binding site located in the E2F3 3' untranslated region (UTR). E2F3 levels were up-regulated in CML-BCCD34+ in a BCR/ABL kinase- and hnRNP-A1 shuttling-dependent manner. Moreover, by using shRNA-mediated E2F3 knock-down and BCR/ABL-transduced lineage-negative bone marrow cells from E2F3+/+ and E2F3-/- mice, we show that E2F3 expression is important for BCR/ABL clonogenic activity and in vivo leukemogenic potential. Thus, the complexity of the mRNA/RBP network, together with the discovery of E2F3 as an hnRNP-A1-regulated factor, outlines the relevant role played by RBPs in posttranscriptional regulation of CML development and progression.
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78
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Ben-Eliezer M, Phillip M, Gat-Yablonski G. Leptin regulates chondrogenic differentiation in ATDC5 cell-line through JAK/STAT and MAPK pathways. Endocrine 2007; 32:235-44. [PMID: 18080100 DOI: 10.1007/s12020-007-9025-y] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2007] [Revised: 07/23/2007] [Accepted: 09/12/2007] [Indexed: 12/19/2022]
Abstract
Leptin, the satiety hormone, has been found to affect growth-plate cartilage development. In the present study, some of the signal transduction pathways that mediate leptin signaling in the ATDC5 chondrogenic cell-line, a model for endochondral ossification, were analyzed. For this purpose, real-time PCR, Western blots and immunofluorescence techniques were used. It was found that leptin increased phosphorylation of ERK1/2, p38, and STAT3 in a time- and dose-dependent manner. Specific inhibition of STAT3 or ERK1/2, but not of P38, blocked the stimulatory effect of leptin on type X collagen mRNA levels. Moreover, leptin induced the translocation of ERK1/2 into the nucleus, as well as c-fos expression, indicating full activation of this cascade. Leptin-induced JNK phosphorylation was not observed, although leptin significantly and rapidly increased JNK protein levels and c-jun mRNA levels. In addition, ERK5 was identified in these cells, but there was no apparent effect of leptin on either its phosphorylation or protein level. The study indicates that the effects of leptin on growth-plate chondrocytes are specifically mediated through ERK1/2 and STAT3, while P38 is not essential for leptin-induced type X collagen expression. This is the first demonstration that these pathways are involved in leptin-induced growth.
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Affiliation(s)
- Miri Ben-Eliezer
- Felsenstein Medical Research Center, 14 Kaplan Street, Petach Tikva, 49202, Israel
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79
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Chakraborty A, Guha S. Granulocyte colony-stimulating factor/granulocyte colony-stimulating factor receptor biological axis promotes survival and growth of bladder cancer cells. Urology 2007; 69:1210-5. [PMID: 17572226 DOI: 10.1016/j.urology.2007.02.035] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2006] [Revised: 01/16/2007] [Accepted: 02/20/2007] [Indexed: 10/23/2022]
Abstract
OBJECTIVES A significant fraction of invasive bladder carcinomas express both granulocyte colony-stimulating factor (G-CSF) and granulocyte colony-stimulating factor receptor (G-CSFR). We sought to determine whether G-CSF/G-CSFR signaling promotes survival and growth of bladder cancer cells. The bladder carcinoma cell line 5637 constitutively secretes G-CSF but lacks G-CSFR expression. In contrast, TCC-SUP lacks expression of both G-CSF and G-CSFR. Using these bladder cancer cell lines as our model systems, we studied the effects of G-CSFR expression on cell proliferation, survival, and growth in vivo. METHODS The TCC-SUP and 5637 cells were transiently transfected with either empty vector (3.1) or G-CSFR (GR). Cell proliferation was assessed with or without G-CSF by MTT assay in TCC-SUP-3.1 and TCC-SUP-GR cells. Apoptosis was examined by flow cytometry in 5637-GR with or without anti-G-CSF antibody and in TCC-SUP-GR in the presence of increasing concentrations of G-CSF. We examined the effects of STAT3 (signal transducer and activator of transcription 3) dominant-negative expression on G-CSF/G-CSFR-mediated STAT3 phosphorylation by Western blotting in TCC-SUP-3.1 and TCC-SUP-GR cells. We characterized the effects of STAT3-dominant-negative expression on G-CSF/G-CSFR-mediated survivin expression by flow cytometry in TCC-SUP-3.1 and TCC-SUP-GR cells. We also examined tumor growth using 5637-3.1 and 5637-GR in the nude mice xenograft model. RESULTS The G-CSF/G-CSFR loop significantly increased proliferation in TCC-SUP-GR cells. Anti-G-CSF antibody significantly increased apoptosis in serum-starved 5637-GR cells, G-CSF abrogated apoptosis in serum-starved TCC-SUP-GR cells in a dose-dependent manner. STAT3-dominant-negative expression blocked G-CSF-mediated STAT3 phosphorylation and survivin expression in TCC-SUP-GR cells. Furthermore, 5637-GR cells produced a significantly larger tumor in the subcutaneous nude mice xenograft model. CONCLUSIONS The G-CSF/G-CSFR autocrine/paracrine signaling loop significantly promotes survival and growth of bladder cancer cells.
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Affiliation(s)
- Arup Chakraborty
- Department of Experimental Therapeutics, University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030, USA.
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