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Brennan MF, Singer S. Five decades of sarcoma care at Memorial Sloan Kettering Cancer Center. J Surg Oncol 2022; 126:896-901. [PMID: 36087086 DOI: 10.1002/jso.27032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 07/02/2022] [Indexed: 11/07/2022]
Abstract
Early studies of the management of soft tissue sarcoma at Memorial Sloan Kettering Cancer Center were influenced by development of robust prospective long-term databases. Increasing capacity for molecular diagnostics has identified a myriad of subtypes with definable natural history. Accurate identification of tissue-specific risk of recurrence and disease-specific survival have increasingly allowed selective use of surgery, radiation therapy, and target-specific cytotoxic and immune therapies.
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Affiliation(s)
- Murray F Brennan
- Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, New York, USA
| | - Samuel Singer
- Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, New York, USA
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Hedgehog pathway dysregulation contributes to the pathogenesis of human gastrointestinal stromal tumors via GLI-mediated activation of KIT expression. Oncotarget 2018; 7:78226-78241. [PMID: 27793025 PMCID: PMC5346634 DOI: 10.18632/oncotarget.12909] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 10/13/2016] [Indexed: 12/20/2022] Open
Abstract
Gastrointestinal stromal tumors (GIST) arise within the interstitial cell of Cajal (ICC) lineage due to activating KIT/PDGFRA mutations. Both ICC and GIST possess primary cilia (PC), which coordinate PDGFRA and Hedgehog signaling, regulators of gastrointestinal mesenchymal development. Therefore, we hypothesized that Hedgehog signaling may be altered in human GIST and controls KIT expression. Quantitative RT-PCR, microarrays, and next generation sequencing were used to describe Hedgehog/PC-related genes in purified human ICC and GIST. Genetic and pharmacologic approaches were employed to investigate the effects of GLI manipulation on KIT expression and GIST cell viability. We report that Hedgehog pathway and PC components are expressed in ICC and GIST and subject to dysregulation during GIST oncogenesis, irrespective of KIT/PDGFRA mutation status. Using genomic profiling, 10.2% of 186 GIST studied had potentially deleterious genomic alterations in 5 Hedgehog-related genes analyzed, including in the PTCH1 tumor suppressor (1.6%). Expression of the predominantly repressive GLI isoform, GLI3, was inversely correlated with KIT mRNA levels in GIST cells and non-KIT/non-PDGFRA mutant GIST. Overexpression of the 83-kDa repressive form of GLI3 or small interfering RNA-mediated knockdown of the activating isoforms GLI1/2 reduced KIT mRNA. Treatment with GLI1/2 inhibitors, including arsenic trioxide, significantly increased GLI3 binding to the KIT promoter, decreased KIT expression, and reduced viability in imatinib-sensitive and imatinib-resistant GIST cells. These data offer new evidence that genes necessary for Hedgehog signaling and PC function in ICC are dysregulated in GIST. Hedgehog signaling activates KIT expression irrespective of mutation status, offering a novel approach to treat imatinib-resistant GIST.
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Li CF, Fang FM, Chen YY, Liu TT, Chan TC, Yu SC, Chen LT, Huang HY. Overexpressed Fatty Acid Synthase in Gastrointestinal Stromal Tumors: Targeting a Progression-Associated Metabolic Driver Enhances the Antitumor Effect of Imatinib. Clin Cancer Res 2017; 23:4908-4918. [PMID: 28442505 DOI: 10.1158/1078-0432.ccr-16-2770] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Revised: 03/02/2017] [Accepted: 04/19/2017] [Indexed: 11/16/2022]
Abstract
Purpose: In gastrointestinal stromal tumors (GIST), lipid-metabolizing enzymes remain underexplored, including fatty acid synthase (FASN).Experimental Design: Forty GISTs were quantitated for FASN mRNA abundance. FASN immunoexpression was informative in 350 GISTs, including 213 with known KIT/PDGFRA/BRAF genotypes. In imatinib-resistant FASN-overexpressing GIST cells, the roles of overexpressed FASN and FASN-targeting C75 in tumor phenotypes, apoptosis and autophagy, KIT transcription, PI3K/AKT/mTOR activation, and imatinib resistance were analyzed by RNAi or myristoylated-AKT transfection. The therapeutic relevance of dual blockade of FASN and KIT was evaluated in vivoResults:FASN mRNA abundance significantly increased from very low/low-risk to high-risk levels of NCCN guidelines (P < 0.0001). FASN overexpression was associated with a nongastric location (P = 0.05), unfavorable genotype (P = 0.005), and increased risk level (P < 0.001) and independently predicted shorter disease-free survival (P < 0.001). In vitro, FASN knockdown inhibited cell growth and migration, inactivated the PI3K/AKT/mTOR pathway, and resensitized resistant GIST cells to imatinib. C75 transcriptionally repressed the KIT promoter, downregulated KIT expression and phosphorylation, induced LC3-II and myristoylated AKT-suppressible activity of caspases 3 and 7, attenuated the PI3K/AKT/mTOR/RPS6/4E-BP1 pathway activation, and exhibited dose-dependent therapeutic additivism with imatinib. Compared with both monotherapies, the C75/imatinib combination more effectively suppressed the growth of xenografts, exhibiting decreased KIT phosphorylation, Ki-67, and phosphorylated PI3K/AKT/mTOR levels and increased TUNEL labeling.Conclusions: We have characterized the prognostic, biological, and therapeutic implications of overexpressed FASN in GISTs. C75 represses KIT transactivation, abrogates PI3K/AKT/mTOR activation, and provides a rationale for dual blockade of KIT and FASN in treating imatinib-resistant GISTs. Clin Cancer Res; 23(16); 4908-18. ©2017 AACR.
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Affiliation(s)
- Chien-Feng Li
- Department of Pathology, Chi-Mei Medical Center, Tainan, Taiwan.,National Institute of Cancer Research, National Health Research Institutes, Tainan, Taiwan.,Department of Biotechnology, Southern Taiwan University of Science and Technology, Tainan, Taiwan.,Department of Pathology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Fu-Min Fang
- Department of Radiation Oncology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Yen-Yang Chen
- Division of Oncology, Department of Internal Medicine, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Ting-Ting Liu
- Department of Pathology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Ti-Chun Chan
- Department of Pathology, Chi-Mei Medical Center, Tainan, Taiwan
| | - Shih-Chen Yu
- Department of Pathology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Li-Tzong Chen
- National Institute of Cancer Research, National Health Research Institutes, Tainan, Taiwan
| | - Hsuan-Ying Huang
- Department of Pathology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan.
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Synthesis and evaluation of 7-substituted-5,6-dihydrobenzo[c]acridine derivatives as new c-KIT promoter G-quadruplex binding ligands. Eur J Med Chem 2017; 130:458-471. [PMID: 28284084 DOI: 10.1016/j.ejmech.2017.02.051] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2016] [Revised: 02/18/2017] [Accepted: 02/20/2017] [Indexed: 11/21/2022]
Abstract
It has been shown that treatment of cancer cells with c-KIT G-quadruplex binding ligands can reduce their c-KIT expression levels thus inhibiting cell proliferation and inducing cell apoptosis. Herein, a series of new 7-substituted-5,6-dihydrobenzo[c]acridine derivatives were designed and synthesized. Subsequent biophysical evaluation demonstrated that the derivatives could effectively bind to and stabilize c-KIT G-quadruplex with good selectivity against duplex DNA. It was found that 12-N-methylated derivatives with a positive charge introduced at 12-position of 5,6-dihydrobenzo[c]acridine ring had similar binding affinity but lower stabilizing ability to c-KIT G-quadruplex DNA, compared with those of nonmethylated derivatives. Further molecular modeling studies showed possible binding modes of G-quadruplex with the ligands. RT-PCR assay and Western blot showed that compound 2b suppressed transcription and translation of c-KIT gene in K562 cells, which was consistent with the property of an effective G-quadruplex binding ligand targeting c-KIT oncogene promoter. Further biological evaluation showed that compound 2b could induce apoptosis through activation of the caspase-3 cascade pathway.
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Zhou W, Bi X, Gao G, Sun L. miRNA-133b and miRNA-135a induce apoptosis via the JAK2/STAT3 signaling pathway in human renal carcinoma cells. Biomed Pharmacother 2016; 84:722-729. [DOI: 10.1016/j.biopha.2016.09.074] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Revised: 09/08/2016] [Accepted: 09/20/2016] [Indexed: 01/15/2023] Open
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Abbaspour Babaei M, Kamalidehghan B, Saleem M, Huri HZ, Ahmadipour F. Receptor tyrosine kinase (c-Kit) inhibitors: a potential therapeutic target in cancer cells. DRUG DESIGN DEVELOPMENT AND THERAPY 2016; 10:2443-59. [PMID: 27536065 PMCID: PMC4975146 DOI: 10.2147/dddt.s89114] [Citation(s) in RCA: 164] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
c-Kit, a receptor tyrosine kinase, is involved in intracellular signaling, and the mutated form of c-Kit plays a crucial role in occurrence of some cancers. The function of c-Kit has led to the concept that inhibiting c-Kit kinase activity can be a target for cancer therapy. The promising results of inhibition of c-Kit for treatment of cancers have been observed in some cancers such as gastrointestinal stromal tumor, acute myeloid leukemia, melanoma, and other tumors, and these results have encouraged attempts toward improvement of using c-Kit as a capable target for cancer therapy. This paper presents the findings of previous studies regarding c-Kit as a receptor tyrosine kinase and an oncogene, as well as its gene targets and signaling pathways in normal and cancer cells. The c-Kit gene location, protein structure, and the role of c-Kit in normal cell have been discussed. Comprehending the molecular mechanism underlying c-Kit-mediated tumorogenesis is consequently essential and may lead to the identification of future novel drug targets. The potential mechanisms by which c-Kit induces cellular transformation have been described. This study aims to elucidate the function of c-Kit for future cancer therapy. In addition, it has c-Kit inhibitor drug properties and their functions have been listed in tables and demonstrated in schematic pictures. This review also has collected previous studies that targeted c-Kit as a novel strategy for cancer therapy. This paper further emphasizes the advantages of this approach, as well as the limitations that must be addressed in the future. Finally, although c-Kit is an attractive target for cancer therapy, based on the outcomes of treatment of patients with c-Kit inhibitors, it is unlikely that Kit inhibitors alone can lead to cure. It seems that c-Kit mutations alone are not sufficient for tumorogenesis, but do play a crucial role in cancer occurrence.
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Affiliation(s)
| | - Behnam Kamalidehghan
- Department of Medical Genetics, National Institute of Genetic Engineering and Biotechnology (NIGEB), Shahrak-e Pajoohesh; Medical Genetics Department, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mohammad Saleem
- Department of Urology; Department of Laboratory Medicine and Pathology, Masonic Cancer Center, University of Minnesota; Section of Molecular Therapeutics & Cancer Health Disparity, The Hormel Institute, Austin, MN, USA
| | - Hasniza Zaman Huri
- Department of Pharmacy, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia; Clinical Investigation Centre, University Malaya Medical Centre, Lembah Pantai, Kuala Lumpur, Malaysia
| | - Fatemeh Ahmadipour
- Department of Pharmacy, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
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Hsueh YS, Chang HH, Chiang NJ, Yen CC, Li CF, Chen LT. MTOR inhibition enhances NVP-AUY922-induced autophagy-mediated KIT degradation and cytotoxicity in imatinib-resistant gastrointestinal stromal tumors. Oncotarget 2015; 5:11723-36. [PMID: 25375091 PMCID: PMC4294368 DOI: 10.18632/oncotarget.2607] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Accepted: 10/21/2014] [Indexed: 01/16/2023] Open
Abstract
Our previous study demonstrated NVP-AUY922, a HSP90AA1 inhibitor, could enhance mutant KIT degradation in gastrointestinal stromal tumor (GIST) cells through both proteasome- and autophagy-mediated pathways. Herein, we showed rapamycin, a MTOR inhibitor and autophagy inducer, could reduce total and phospho-KIT expression levels and enhance apoptosis in imatinib-resistant GIST cells. The involvement of autophagy in rapamycin-induced KIT downregulation was further confirmed by co-localization of KIT and autophagosome, and partial recovery of KIT expression level by either siRNA-mediated BECN1 and ATG5 silencing or autophagy inhibitors after rapamycin. Rapamycin and NVP-AUY922 synergistically inhibited GIST cells growth in vitro. The combination of low-dose NVP-AUY922 with rapamycin had comparable effects on reducing KIT expression, increasing MAP1LC3B puncta and tumor necrosis, and inhibiting tumor growth as high-dose NVP-AUY922 did in GIST430 xenograft model. Our results suggest the addition of a MTOR inhibitor may reduce NVP-AUY922 dose requirement and potentially improve its therapeutic index in mutant KIT-expressing GISTs.
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Affiliation(s)
- Yuan-Shuo Hsueh
- National Institute of Cancer Research, National Health Research Institutes, Tainan, Taiwan
| | - Hui Hua Chang
- Institute of Clinical Pharmacy and Pharmaceutical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Nai-Jung Chiang
- National Institute of Cancer Research, National Health Research Institutes, Tainan, Taiwan. Department of Internal Medicine, National Cheng Kung University Hospital, Tainan, Taiwan
| | - Chueh-Chuan Yen
- Division of Hematology and Oncology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan. National Yang-Ming University School of Medicine, Taipei, Taiwan
| | - Chien-Feng Li
- National Institute of Cancer Research, National Health Research Institutes, Tainan, Taiwan. Department of Pathology, Chi-Mei Foundation Medical Center, Tainan, Taiwan. Department of Biotechnology, Southern Taiwan University of Science and Technology, Tainan, Taiwan. Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Li-Tzong Chen
- National Institute of Cancer Research, National Health Research Institutes, Tainan, Taiwan. Institute of Clinical Pharmacy and Pharmaceutical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan. Department of Internal Medicine, National Cheng Kung University Hospital, Tainan, Taiwan. Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwann
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Ihle MA, Trautmann M, Kuenstlinger H, Huss S, Heydt C, Fassunke J, Wardelmann E, Bauer S, Schildhaus HU, Buettner R, Merkelbach-Bruse S. miRNA-221 and miRNA-222 induce apoptosis via the KIT/AKT signalling pathway in gastrointestinal stromal tumours. Mol Oncol 2015; 9:1421-33. [PMID: 25898773 DOI: 10.1016/j.molonc.2015.03.013] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Accepted: 03/30/2015] [Indexed: 02/09/2023] Open
Abstract
Aberrantly expressed microRNAs (miRNAs) are involved in many diseases including cancer. In gastrointestinal stromal tumours (GISTs) expression of miR-221 and miR-222 is reduced compared to control tissue and other sarcomas but the functional effects of this downregulation are not fully understood. This study aimed at evaluating the miR-221 and miR-222 expression profiles in different GIST subtypes and the functional role of these miRNAs. Expression of miR-221 and miR-222 was analysed in six KIT exon 9 and three KIT exon 11 mutated and nine wildtype GISTs by qPCR. Viability and apoptosis were examined in three different, KIT positive GIST cell lines (GIST882, GIST-T1 and GIST48) after overexpression of these miRNAs. The modulation of KIT and the PI3K/AKT pathways was determined by Western blot. Wildtype and KIT mutated GISTs revealed reduced miRNA expression compared to adequate control tissue. miRNA expression was lower for wildtype compared to mutated GISTs. Transient transfection of miR-221 and miR-222 reduced viability and induced apoptosis by inhibition of KIT expression and its phosphorylation and activation of caspases 3 and 7 in all three GIST cell lines. p-AKT, AKT and BCL2 expression was reduced after miRNA transfection whereas only slight influence on p-MTOR, MTOR and BCL2L11 (BIM) was detected. Our results demonstrate that miR-221 and miR-222 which are downregulated in wildtype and mutated GISTs, induce apoptosis in vitro by a signalling cascade involving KIT, AKT and BCL2. Therefore, overexpression of these miRNAs seems to functionally counteract oncogenic signalling pathways in GIST.
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Affiliation(s)
| | - Marcel Trautmann
- Institute of Pathology, University of Cologne, Medical Centre, Cologne, Germany
| | - Helen Kuenstlinger
- Institute of Pathology, University of Cologne, Medical Centre, Cologne, Germany
| | - Sebastian Huss
- Institute of Pathology, University of Cologne, Medical Centre, Cologne, Germany
| | - Carina Heydt
- Institute of Pathology, University of Cologne, Medical Centre, Cologne, Germany
| | - Jana Fassunke
- Institute of Pathology, University of Cologne, Medical Centre, Cologne, Germany
| | - Eva Wardelmann
- Institute of Pathology, University of Cologne, Medical Centre, Cologne, Germany
| | - Sebastian Bauer
- Sarcoma Centre, West German Cancer Centre, University of Essen, Essen, Germany
| | | | - Reinhard Buettner
- Institute of Pathology, University of Cologne, Medical Centre, Cologne, Germany
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Bottardi S, Mavoungou L, Pak H, Daou S, Bourgoin V, Lakehal YA, Affar EB, Milot E. The IKAROS interaction with a complex including chromatin remodeling and transcription elongation activities is required for hematopoiesis. PLoS Genet 2014; 10:e1004827. [PMID: 25474253 PMCID: PMC4256266 DOI: 10.1371/journal.pgen.1004827] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Accepted: 10/14/2014] [Indexed: 12/15/2022] Open
Abstract
IKAROS is a critical regulator of hematopoietic cell fate and its dynamic expression pattern is required for proper hematopoiesis. In collaboration with the Nucleosome Remodeling and Deacetylase (NuRD) complex, it promotes gene repression and activation. It remains to be clarified how IKAROS can support transcription activation while being associated with the HDAC-containing complex NuRD. IKAROS also binds to the Positive-Transcription Elongation Factor b (P-TEFb) at gene promoters. Here, we demonstrate that NuRD and P-TEFb are assembled in a complex that can be recruited to specific genes by IKAROS. The expression level of IKAROS influences the recruitment of the NuRD-P-TEFb complex to gene regulatory regions and facilitates transcription elongation by transferring the Protein Phosphatase 1α (PP1α), an IKAROS-binding protein and P-TEFb activator, to CDK9. We show that an IKAROS mutant that is unable to bind PP1α cannot sustain gene expression and impedes normal differentiation of IkNULL hematopoietic progenitors. Finally, the knock-down of the NuRD subunit Mi2 reveals that the occupancy of the NuRD complex at transcribed regions of genes favors the relief of POL II promoter-proximal pausing and thereby, promotes transcription elongation. Perturbation of the expression level of IKAROS, a transcription factor critical during hematopoiesis, is associated with malignant transformation in mice and humans. The importance of IKAROS expression levels for the control of target-gene regulation was addressed in hematopoietic progenitor cells. The collaboration between IKAROS and the Nucleosome Remodeling and Deacetylase (NuRD) complex can promote gene activation or repression. IKAROS can also interact with the Positive-Transcription Elongation Factor b (P-TEFb) and the Protein Phosphatase 1 (PP1), an important P-TEFb regulator. Immunoaffinity purification of IKAROS interacting proteins and Fast Protein Liquid Chromatography analysis revealed a dynamic interaction between IKAROS, PP1 and the newly defined NuRD-P-TEFb complex. This complex can be targeted to specific genes in cells expressing high levels of IKAROS to promote productive transcription elongation. Based on our results we suggest that, in addition to P-TEFb, the NuRD complex and PP1 are required to facilitate transcription elongation of IKAROS-target genes and normal differentiation of hematopoietic progenitor cells.
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Affiliation(s)
- Stefania Bottardi
- Maisonneuve Rosemont Hospital Research Center, Maisonneuve-Rosemont Hospital and Faculty of Medicine, University of Montreal, Montreal, Quebec, Canada
| | - Lionel Mavoungou
- Maisonneuve Rosemont Hospital Research Center, Maisonneuve-Rosemont Hospital and Faculty of Medicine, University of Montreal, Montreal, Quebec, Canada
| | - Helen Pak
- Maisonneuve Rosemont Hospital Research Center, Maisonneuve-Rosemont Hospital and Faculty of Medicine, University of Montreal, Montreal, Quebec, Canada
| | - Salima Daou
- Maisonneuve Rosemont Hospital Research Center, Maisonneuve-Rosemont Hospital and Faculty of Medicine, University of Montreal, Montreal, Quebec, Canada
| | - Vincent Bourgoin
- Maisonneuve Rosemont Hospital Research Center, Maisonneuve-Rosemont Hospital and Faculty of Medicine, University of Montreal, Montreal, Quebec, Canada
| | - Yahia A. Lakehal
- Maisonneuve Rosemont Hospital Research Center, Maisonneuve-Rosemont Hospital and Faculty of Medicine, University of Montreal, Montreal, Quebec, Canada
| | - El Bachir Affar
- Maisonneuve Rosemont Hospital Research Center, Maisonneuve-Rosemont Hospital and Faculty of Medicine, University of Montreal, Montreal, Quebec, Canada
| | - Eric Milot
- Maisonneuve Rosemont Hospital Research Center, Maisonneuve-Rosemont Hospital and Faculty of Medicine, University of Montreal, Montreal, Quebec, Canada
- * E-mail:
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Chung HY. Contradictory results of gene expression analysis affected by flavopiridol: comment on the article by Yik et Al. Arthritis Rheumatol 2014; 66:3525-6. [PMID: 25155262 DOI: 10.1002/art.38820] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Hye Yoon Chung
- Yonsei University College of Medicine, Seoul, Republic of Korea
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Abstract
Gastrointestinal stromal tumor (GIST) is the most common sarcoma of the intestinal tract. Nearly all tumors have a mutation in the KIT or, less often, platelet-derived growth factor receptor (PDGFRA) or B-rapidly Accelerated Fibrosarcoma (BRAF) gene. The discovery of constitutive KIT activation as the central mechanism of GIST pathogenesis, suggested that inhibiting or blocking KIT signaling might be the milestone in the targeted therapy of GISTs. Indeed, imatinib mesylate inhibits KIT kinase activity and represents the front line drug for the treatment of unresectable and advanced GISTs, achieving a partial response or stable disease in about 80% of patients with metastatic GIST. KIT mutation status has a significant impact on treatment response. Patients with the most common exon 11 mutation experience higher rates of tumor shrinkage and prolonged survival, as tumors with an exon 9 mutation or wild-type KIT are less likely to respond to imatinib. Although imatinib achieves a partial response or stable disease in the majority of GIST patients, complete and lasting responses are rare. About half of the patients who initially benefit from imatinib treatment eventually develop drug resistance. The most common mechanism of resistance is through polyclonal acquisition of second site mutations in the kinase domain, which highlights the future therapeutic challenges in salvaging these patients after failing kinase inhibitor monotherapies. More recently, sunitinib (Sutent, Pfizer, New York, NY), which inhibits vascular endothelial growth factor receptor (VEGFR) in addition to KIT and PDGFRA, has proven efficacious in patients who are intolerant or refractory to imatinib. This review summarizes the recent knowledge on targeted therapy in GIST, based on the central role of KIT oncogenic activation, as well as discussing mechanisms of resistance.
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Tao L, Fu R, Wang X, Yao J, Zhou Y, Dai Q, Li Z, Lu N, Wang W. LL-202, a newly synthesized flavonoid, inhibits tumor growth via inducing G2/M phase arrest and cell apoptosis in MCF-7 human breast cancer cells in vitro and in vivo. Toxicol Lett 2014; 228:1-12. [DOI: 10.1016/j.toxlet.2014.04.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Revised: 03/31/2014] [Accepted: 04/03/2014] [Indexed: 10/25/2022]
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Patwardhan PP, Surriga O, Beckman MJ, de Stanchina E, Dematteo RP, Tap WD, Schwartz GK. Sustained inhibition of receptor tyrosine kinases and macrophage depletion by PLX3397 and rapamycin as a potential new approach for the treatment of MPNSTs. Clin Cancer Res 2014; 20:3146-58. [PMID: 24718867 DOI: 10.1158/1078-0432.ccr-13-2576] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE Malignant peripheral nerve sheath tumor (MPNST) is a highly aggressive tumor type that is resistant to chemotherapy and there are no effective therapies. MPNSTs have been shown to have gene amplification for receptor tyrosine kinases (RTK), PDGFR and c-Kit. We tested the c-Kit inhibitor, imatinib, and PLX3397, a selective c-Fms and c-Kit inhibitor, to evaluate their efficacy against MPNST cells in vitro and in vivo. EXPERIMENTAL DESIGN We tested the efficacy of imatinib or PLX3397 either alone or in combination with TORC1 inhibitor rapamycin in a cell proliferation assay in vitro and by immunoblotting to determine target inhibition. Immunoblotting and immunohistochemical analysis was further carried out using xenograft samples in vivo. RESULTS Our in vitro studies show that imatinib and PLX3397 similarly inhibit cell growth and this can be enhanced with rapamycin with comparable target specificity. However, in vivo studies clearly demonstrate that compared with imatinib, PLX3397 results in sustained blockade of c-Kit, c-Fms, and PDGFRβ, resulting in significant suppression of tumor growth. Moreover, staining for Iba-1, a marker for macrophages, indicates that PLX3397 results in significant depletion of macrophages in the growing tumors. The combination of PLX3397 and rapamycin results in even greater macrophage depletion with continued growth suppression, even when the drug treatment is discontinued. CONCLUSIONS Taken together, our data strongly suggest that PLX3397 is superior to imatinib in the treatment of MPNSTs, and the combination of PLX3397 with a TORC1 inhibitor could provide a new therapeutic approach for the treatment of this disease.
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Affiliation(s)
- Parag P Patwardhan
- Authors' Affiliations: Jennifer Goodman Linn Laboratory of New Drug Development, Department of Medicine, Department of Molecular Pharmacology and Chemistry, Department of Surgery, Memorial Sloan Kettering Cancer Center; and Division of Hematology/Oncology, Columbia University Medical Center, New York, New York
| | - Oliver Surriga
- Authors' Affiliations: Jennifer Goodman Linn Laboratory of New Drug Development, Department of Medicine, Department of Molecular Pharmacology and Chemistry, Department of Surgery, Memorial Sloan Kettering Cancer Center; and Division of Hematology/Oncology, Columbia University Medical Center, New York, New York
| | - Michael J Beckman
- Authors' Affiliations: Jennifer Goodman Linn Laboratory of New Drug Development, Department of Medicine, Department of Molecular Pharmacology and Chemistry, Department of Surgery, Memorial Sloan Kettering Cancer Center; and Division of Hematology/Oncology, Columbia University Medical Center, New York, New York
| | - Elisa de Stanchina
- Authors' Affiliations: Jennifer Goodman Linn Laboratory of New Drug Development, Department of Medicine, Department of Molecular Pharmacology and Chemistry, Department of Surgery, Memorial Sloan Kettering Cancer Center; and Division of Hematology/Oncology, Columbia University Medical Center, New York, New York
| | - Ronald P Dematteo
- Authors' Affiliations: Jennifer Goodman Linn Laboratory of New Drug Development, Department of Medicine, Department of Molecular Pharmacology and Chemistry, Department of Surgery, Memorial Sloan Kettering Cancer Center; and Division of Hematology/Oncology, Columbia University Medical Center, New York, New York
| | - William D Tap
- Authors' Affiliations: Jennifer Goodman Linn Laboratory of New Drug Development, Department of Medicine, Department of Molecular Pharmacology and Chemistry, Department of Surgery, Memorial Sloan Kettering Cancer Center; and Division of Hematology/Oncology, Columbia University Medical Center, New York, New York
| | - Gary K Schwartz
- Authors' Affiliations: Jennifer Goodman Linn Laboratory of New Drug Development, Department of Medicine, Department of Molecular Pharmacology and Chemistry, Department of Surgery, Memorial Sloan Kettering Cancer Center; and Division of Hematology/Oncology, Columbia University Medical Center, New York, New York
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Abstract
Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumor of the gastrointestinal tract. Soon after GIST was recognized as a tumor driven by a KIT or platelet-derived growth factor receptor mutation, it became the first solid tumor target for tyrosine kinase inhibitor therapies. More recently, alternative molecular mechanisms for GIST pathogenesis have been discovered. These are related to deficiencies in the succinate dehydrogenase complex, NF1-gene alterations in connection with neurofibromatosis type 1 tumor syndrome, and mutational activation of the BRAF oncogene in very rare cases.
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Affiliation(s)
- Markku Miettinen
- Laboratory of Pathology, NCI/NIH, 9000 Rockville Pike, Building 10, Rm. 2B50, Bethesda, Maryland 20892,
| | - Jerzy Lasota
- Laboratory of Pathology, NCI/NIH, 9000 Rockville Pike, Building 10, Rm. 2B50, Bethesda, Maryland 20892,
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Shen FH, Jin J, Li J, Wang Y, Zhu SH, Lu YJ, Ou TM, Huang ZS, Huang M, Huang ZY. The G-quadruplex ligand, SYUIQ-FM05, targets proto-oncogene c-kit transcription and induces apoptosis in K562 cells. PHARMACEUTICAL BIOLOGY 2013; 51:447-454. [PMID: 23363047 DOI: 10.3109/13880209.2012.738424] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
CONTEXT N'-(7-Fluoro-5-N-methyl-10H-indolo[3,2-b]quinolin-5-ium)-N,N-dimethylpropane-1,3-diamine iodide (SYUIQ-FM05) is a semi-synthetic derivative of cryptolepine which is from Cryptolepis sanguinolenta (Lindl.) Schlechter (Periplocaeae). This ligand inhibits telomerase activity by stabilizing the G-quadruplex structure and induces growth arrest in cancer cells. OBJECTIVE The anticancer activity of SYUIQ-FM05 via inhibiting c-kit transcription was investigated in leukemic cells. MATERIALS AND METHODS The cytotoxicity of SYUIQ-FM05 in K562 cells was evaluated using a cell viability assay and flow cytometry (FCM) at 0.4, 2.0, 10.0 and 20.0 nM. Under the same concentrations of SYUIQ-FM05 or 100 nM imatinib mesylate (IM), quantitative polymerase chain reaction (Q-PCR) investigated transcription of c-kit and bcl-2, and western blotting analyzed the expression levels of c-Kit, total mitogen-activated protein kinase kinases (MEKs), phospho-MEK (p-MEK), total extracellular regulated protein kinases (ERKs), phospho-ERK (p-ERK), Bcl-2 and Bax. RESULTS SYUIQ-FM05 inhibited cellular growth with an IC(50) of 10.83 ± 0.05 nM in K562 cells. c-Kit transcription was suppressed 2.69-, 4.39-, 7.71- and 10.52-fold at 0.4, 2.0, 10.0 and 20.0 nM SYUIQ-FM05, respectively, which produced proportional loss of total c-Kit protein except IM. Both SYUIQ-FM05 and IM downregulated p-MEK and p-ERK. Furthermore, bcl-2 transcription was suppressed 1.58- and 1.86-fold at 10.0 and 20.0 nM SYUIQ-FM05, respectively, but 0.4 and 2.0 nM SYUIQ-FM05 had no effect. A decrease in Bcl-2 and an increase in Bax appeared in these treated cells. DISCUSSION AND CONCLUSION These findings demonstrate that SYUIQ-FM05 could induce apoptosis in a leukemic cell line through inhibiting c-kit transcription, which supports the anticancer potency of SYUIQ-FM05 in c-Kit-positive leukemic cells.
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Affiliation(s)
- Fei-Hai Shen
- Center of Preclinical Screening and Evaluation on New Drug, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, PR China
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16
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Locascio LE, Donoghue DJ. KIDs rule: regulatory phosphorylation of RTKs. Trends Biochem Sci 2013; 38:75-84. [PMID: 23312584 DOI: 10.1016/j.tibs.2012.12.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2012] [Revised: 11/29/2012] [Accepted: 12/03/2012] [Indexed: 01/14/2023]
Abstract
Receptor tyrosine kinases (RTKs) are mediators of multiple cell signaling networks linked to cell growth and differentiation. In general, they exhibit similar overall structure with a ligand-binding extracellular domain and a conserved intracellular tyrosine kinase domain. In many RTKs, the kinase domain is interrupted by a sequence known as the kinase insert domain (KID). In addition to phosphorylation sites within the kinase domain, regulatory phosphorylation also occurs within the KID of several RTKs important in human health and disease. Phosphorylation of specific Tyr or Ser residues within the KID of some RTKs triggers distinct cellular signaling outcomes. Here, we review the functionality of KIDs throughout all RTK families, and provide justification for further study of this often-overlooked domain.
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Affiliation(s)
- Lauren E Locascio
- Department of Chemistry and Biochemistry, Moores UCSD Cancer Center, University of California San Diego, La Jolla, CA 92093-0367, USA
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17
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Hsueh YS, Yen CC, Shih NY, Chiang NJ, Li CF, Chen LT. Autophagy is involved in endogenous and NVP-AUY922-induced KIT degradation in gastrointestinal stromal tumors. Autophagy 2012. [PMID: 23196876 PMCID: PMC3552885 DOI: 10.4161/auto.22802] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Gastrointestinal stromal tumor (GIST) is a prototype of mutant KIT oncogene-driven tumor. Prolonged tyrosine kinase inhibitor (TKI) treatment may result in a resistant phenotype through acquired secondary KIT mutation. Heat shock protein 90 (HSP90AA1) is a chaperone protein responsible for protein maturation and stability, and KIT is a known client protein of HSP90AA1. Inhibition of HSP90AA1 has been shown to destabilize KIT protein by enhancing its degradation via the proteasome-dependent pathway. In this study, we demonstrated that NVP-AUY922 (AUY922), a new class of HSP90AA1 inhibitor, is effective in inhibiting the growth of GIST cells expressing mutant KIT protein, the imatinib-sensitive GIST882 and imatinib-resistant GIST48 cells. The growth inhibition was accompanied with a sustained reduction of both total and phosphorylated KIT proteins and the induction of apoptosis in both cell lines. Surprisingly, AUY922-induced KIT reduction could be partially reversed by pharmacological inhibition of either autophagy or proteasome degradation pathway. The blockade of autophagy alone led to the accumulation of the KIT protein, highlighting the role of autophagy in endogenous KIT turnover. The involvement of autophagy in endogenous and AUY922-induced KIT protein turnover was further confirmed by the colocalization of KIT with MAP1LC3B-, acridine orange- or SQSTM1-labeled autophagosome, and by the accumulation of KIT in GIST cells by silencing either BECN1 or ATG5 to disrupt autophagosome activity. Therefore, the results not only highlight the potential application of AUY922 for the treatment of KIT-expressing GISTs, but also provide the first evidence for the involvement of autophagy in endogenous and HSP90AA1 inhibitor-induced KIT degradation.
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Affiliation(s)
- Yuan-Shuo Hsueh
- Institute of Clinical Pharmacy and Pharmaceutical Science, National Cheng Kung University, Tainan, Taiwan
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18
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Wu Y, Chen C, Sun X, Shi X, Jin B, Ding K, Yeung SCJ, Pan J. Cyclin-dependent kinase 7/9 inhibitor SNS-032 abrogates FIP1-like-1 platelet-derived growth factor receptor α and bcr-abl oncogene addiction in malignant hematologic cells. Clin Cancer Res 2012; 18:1966-78. [PMID: 22447844 DOI: 10.1158/1078-0432.ccr-11-1971] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE The "gate-keeper" mutations T674I platelet-derived growth factor receptor α (PDGFRα) in hypereosinophilic syndrome (HES) and T315I Bcr-Abl in chronic myeloid leukemia (CML) are resistant to imatinib and the second-generation small-molecule tyrosine kinase inhibitors (TKI). However, to combat acquired resistance to imatinib, an alternative approach is to decrease the expression of the addicted gene to efficiently kill resistant malignant hematologic cells. The purpose of this study was to evaluate the strategy of shutting down the transcription and expression of FIP1-like-1 (FIP1L1)-PDGFRα and Bcr-Abl with SNS-032, an inhibitor of cyclin-dependent kinase 7 (CDK7) and CDK9 in phase I clinical trials. EXPERIMENTAL DESIGN The effects of SNS-032 on PDGFRα and Bcr-Abl signaling pathways, apoptosis, and cell cycling were analyzed in TKI-resistant cells of HES and CML. The in vivo antitumor activity of SNS-032 was assessed with xenografted BaF3-T674I FIP1L1-PDGFRα and KBM5-T315I Bcr-Abl cells in nude mouse models. RESULTS SNS-032 inhibited the phosphorylation on Ser5 and Ser2 of RNA polymerase II. SNS-032 decreased both the mRNA and protein levels of FIP1L1-PDGFRα and Bcr-Abl and inhibited the proliferation of malignant cells expressing FIP1L1-PDGFRα or Bcr-Abl. It also decreased the phosphorylation of downstream molecules. It induced apoptosis by triggering both the mitochondrial pathway and the death receptor pathway. CONCLUSIONS This CDK7/9 inhibitor potently inhibits FIP1L1-PDGFRα-positive HES cells and Bcr-Abl-positive CML cells regardless of their sensitivity to imatinib. SNS-032 may have potential in treating hematologic malignancy by abrogating oncogene addiction.
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Affiliation(s)
- Yongbin Wu
- Department of Pathophysiology, Zhongshan School of Medicine, Sun Yat-Sen University, 74 Zhongshan Road II, Guangzhou 510089, PR China
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Transcription inhibition as a therapeutic target for cancer. Cancers (Basel) 2011; 3:4170-90. [PMID: 24213132 PMCID: PMC3763417 DOI: 10.3390/cancers3044170] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2011] [Revised: 11/14/2011] [Accepted: 11/16/2011] [Indexed: 01/10/2023] Open
Abstract
During tumorigenesis the transformed cells lose their normal growth control mechanisms and become dependent on oncogenes' products and pathways for survival. Treatments tailored to block the expression or function of transforming genes have shown efficacy in eliminating neoplastic cells. The mRNAs of many oncogenes, as well as regulators of other key processes such as cell proliferation, angiogenesis, and apoptosis, typically have shorter half-lives. Agents that impede mRNA synthesis are expected to selectively hinder the expression of these genes and, therefore, be detrimental to neoplastic cells that are physiologically dependent on them. In addition to exploiting the tumor cells' dependency on short-lived transcripts, RNA-directed agents also take advantage of the differential sensitivity between transformed and non-transformed cells, as the cytotoxic effects of inhibiting RNA synthesis have not been seen in non-transformed cells. The abrogation of the formation of oncotranscripts provides a new concept in cancer therapeutics and numerous agents have been developed which are able to target transcription. The focus of this review is to give an overview of transcription and the different inhibitory strategies that target various aspects of the transcriptional process.
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20
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Is autophagy rather than apoptosis the regression driver in imatinib-treated gastrointestinal stromal tumors? Transl Oncol 2011; 1:177-86. [PMID: 19043528 DOI: 10.1593/tlo.08157] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2008] [Revised: 09/04/2008] [Accepted: 09/08/2008] [Indexed: 12/23/2022] Open
Abstract
Although apoptosis (programmed cell death type I) is more frequently reported in the literature in imatinib-treated gastrointestinal stromal tumor (GIST) cell lines,morphological features consistent with autophagic changes aremore often encountered in surgical specimens of treated patients. Autophagy (programmed cell death type II) is highly regulated by a tumor-suppressor mechanism that mainly involves the genes beclin1, PI3KIII, and bcl2. Being our material not suitable for electron microscopy analysis (not paraformaldehyde-glutaraldehyde-fixed), we evaluated the morphological, biochemical, and immunophenotypical profiles expected to be related to autophagy and apoptosis in a series of surgically resected samples taken from 11 imatinib-treated patients with molecularly characterized GISTs. The samples were examined for imatinib-induced morphological changes, the presence/interactions of the autophagic-related proteins (beclin1, PI3KIII, bcl2, and LC3-II) and the presence of apoptosis-related proteins (caspase 3, caspase 7, and lamin A/C) by means ofWestern blot analysis and coimmunoprecipitation, complemented by immunohistochemistry. We also studied samples of two untreated GISTs used as controls. Sampling areas with different residual cellularity scores fromboth the imatinib-treated and untreated patients showed biochemical and immunohistochemical evidence of high levels of proautophagy beclin1/PI3KIII and low levels of antiautophagy beclin1/bcl2 complexes, together with the presence of LC3-II detected by Western blot analysis, thus supporting the presence of autophagy. There was no expression of cleaved/activated caspase 3 or 7 or cleaved lamin A/C. Our descriptive results support the idea that GISTs activate autophagy rather than apoptosis in response to imatinib treatment and that their molecular makeup includes fingerprints of autophagy.
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MicroRNA-193b regulates c-Kit proto-oncogene and represses cell proliferation in acute myeloid leukemia. Leuk Res 2011; 35:1226-32. [PMID: 21724256 DOI: 10.1016/j.leukres.2011.06.010] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2010] [Revised: 06/03/2011] [Accepted: 06/09/2011] [Indexed: 11/21/2022]
Abstract
Mutations and/or overexpression of c-Kit proto-oncogene frequently occur in subsets of acute myeloid leukemia (AML) and contribute to abnormal cell proliferation and poor outcomes. We showed that c-Kit expression was subject to post-transcriptional regulation by microRNA (miRNA)-193b. Notably, miR-193b was significantly down-regulated in the examined AML cells and its levels were inversely correlated with c-Kit levels. Restoration of miR-193b expression in AML cells resulted in distinctly reduced c-Kit expression and inhibited cell growth. These data reveal a role for miR-193b dysregulation in myeloid leukemogenesis and the therapeutic promise of regulating miR-193b expression for c-Kit-positive AML.
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22
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Affiliation(s)
- Maria Y Ho
- Division of Medical Oncology, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
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23
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Gastrointestinal stromal tumors: morphological, immunohistochemical and molecular changes associated with kinase inhibitor therapy. Pathol Oncol Res 2011; 17:455-61. [PMID: 21279555 DOI: 10.1007/s12253-011-9362-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2010] [Accepted: 01/06/2011] [Indexed: 01/23/2023]
Abstract
Recurrent or metastatic GISTs are currently treated with kinase inhibitors since they achieves disease control in 70-85% of patients but this response depend on KIT and PDGFRA gene mutation status. We review the morfological and molecular findings associated to kinase inhibitors administration in GISTs based on the literature on Medline and authors' own experience. The initial response to kinase inhibitors (imatinib mesylate, Gleevec, Novartis) usually is partial and depend on the mutational KIT or PDGFRA state. Amongst patients wih KIT mutations, the best results are achived in those harboring exon 11 (85%) and exon 9 (45%) mutations. GISTs harboring PDGFRA gene mutations generally respond favorably except those involving the Asp842Val mutation. In the absence of KIT/PDGFRA gene mutations, partial response or disease stabilization is reported in 23% and 50% of patients, respectively, and disease progression in 19%. Histological examination of tumors displaying an initial response to imatinib reveals a highly-variable reduction in the number of tumor cells, a decline in the proliferative index, myxohyaline or sclerohyaline stroma, and a varying degree of bleeding and edema, necrosis and cystification. 72% of patients with initial good response to imatinib, display metastases or new nodule growth within an existing clinically-quiescent tumor after 12-36 months of treatment. This secondary resistance is characterized by a number of well-defined morphological and molecular changes. Histologically, the new growths display increased mitotic activity, pleomorphism, an epithelioid or mixed phenotype and persistent KIT expression although more rarely, dedifferentiation and loss of KIT expression (Fig. 4), as well as trans-differentiation into a rhabdomyosarcoma or epithelial phenotype has been reported. Molecularly, 46-67% of patients present additional KIT mutations, generally in the kinase domain (exons 13, 14 and 17) but also in the ATP-binding domain (exons 15,16) of the same allele. Secondary PDGFRA mutations are very rare. Secondary mutations have not been observed in GISTs not harboring KIT/PDGFRA mutations, or in tumors displaying an unusual morphology or loss of CD117 expression. A number of studies highlight the presence of different resistance mutations within different new tumor nodules, as well as the simultaneous development of distinct resistant tumor subclones within a single lesion (acquired polyclonal resistance). Secondary mutation in genes other than KIT/PDGFRA has only been reported in BRAF (Val600Glu).
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Synergistic induction of apoptosis by the Bcl-2 inhibitor ABT-737 and imatinib mesylate in gastrointestinal stromal tumor cells. Mol Oncol 2010; 5:93-104. [PMID: 21115411 DOI: 10.1016/j.molonc.2010.10.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2010] [Revised: 10/07/2010] [Accepted: 10/08/2010] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Although imatinib mesylate has revolutionized the management of patients with gastrointestinal stromal tumor (GIST), resistance and progression almost inevitably develop with long-term monotherapy. To enhance imatinib-induced cytotoxicity and overcome imatinib-resistance in GIST cells, we examined the antitumor effects of the pro-apoptotic Bcl-2/Bcl-x(L) inhibitor ABT-737, alone and in combination with imatinib. METHODS We treated imatinib-sensitive, GIST-T1 and GIST882, and imatinib-resistant cells with ABT-737 alone and with imatinib. We determined the anti-proliferative and apoptotic effects by cell viability assay, flow cytometric apoptosis and cell cycle analysis, immunoblotting, and nuclear morphology. Synergism was determined by isobologram analysis. RESULTS The IC(50) of single-agent ABT-737 at 72 h was 10 μM in imatinib-sensitive GIST-T1 and GIST882 cells, and 1 μM in imatinib-resistant GIST48IM cells. ABT-737 and imatinib combined synergistically in a time- and dose-dependent manner to inhibit the proliferation and induce apoptosis of all GIST cells, as evidenced by cell viability and apoptosis assays, caspase activation, PARP cleavage, and morphologic changes. Isobologram analyses revealed strongly synergistic drug interactions, with combination indices <0.5 for most ABT-737/imatinib combinations. Thus, clinically relevant in vitro concentrations of ABT-737 have single-agent antitumor activity and are synergistic in combination with imatinib. CONCLUSION We provide the first preclinical evidence that Bcl-2/Bcl-x(L) inhibition with ABT-737 synergistically enhances imatinib-induced cytotoxicity via apoptosis, and that direct engagement of apoptotic cell death may be an effective approach to circumvent imatinib-resistance in GIST.
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A dose-finding, pharmacokinetic and pharmacodynamic study of a novel schedule of flavopiridol in patients with advanced solid tumors. Invest New Drugs 2010; 30:629-38. [PMID: 20938713 DOI: 10.1007/s10637-010-9563-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2010] [Accepted: 10/03/2010] [Indexed: 10/19/2022]
Abstract
PURPOSE Based on the promising activity and tolerability of flavopiridol administered with a pharmacokinetically-derived dosing schedule in chronic lymphocytic leukemia (CLL), we conducted a phase I study using this schedule in patients with advanced solid tumors. EXPERIMENTAL DESIGN Flavopiridol was given IV as a 30-min loading dose followed by a 4-hr infusion weekly for 4 weeks repeated every 6 weeks. Dose-escalation was in cohorts of three patients using the standard 3+3 phase I study design. Blood samples were obtained for pharmacokinetic and pharmacodynamic studies. RESULTS Thirty-four eligible patients with advanced solid tumors received a total of 208 doses (median 7, range 1-24). Total doses ranged from 40 to 105 mg/m(2). The primary dose limiting toxicity was cytokine release syndrome (CKRS). No antitumor responses were observed. The mean peak plasma concentration across all doses was 1.65 ± 0.86 μM. Area under the concentration-versus-time curve ([Formula: see text]) ranged from 4.31 to 32.2 μM[Symbol: see text]hr with an overall mean of 13.6 ± 7.0 μM[Symbol: see text]hr. Plasma flavopiridol concentrations and AUC increased proportionally with dose. There was no correlation between cytokine levels and clinical outcomes. CONCLUSIONS The maximum-tolerated dose of flavopiridol is 20 mg/m(2) bolus followed by 20 mg/m(2) infusion over 4 h given weekly for 4 weeks on a 6-week cycle in patients with advanced solid tumors. Flavopiridol PK was notably different, and there was a higher frequency of CKRS, despite prophylactic steroids, seen in this patient group compared to previous studies with CLL using a similar dosing schedule.
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Bayraktar UD, Bayraktar S, Rocha-Lima CM. Molecular basis and management of gastrointestinal stromal tumors. World J Gastroenterol 2010; 16:2726-34. [PMID: 20533592 PMCID: PMC2883128 DOI: 10.3748/wjg.v16.i22.2726] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Molecularly targeted agents have dramatically impacted the management of several cancers. Targeting KIT has led to a new treatment paradigm in gastrointestinal stromal tumors (GISTs). KIT is a cell surface receptor with tyrosine kinases that, upon binding of its ligand, stem cell factor, activates various signaling pathways. Imatinib and sunitinib, both tyrosine kinase inhibitors directed to KIT, were approved for first- and second-line treatment of metastatic and unresectable GISTs. In this article, we will review the molecular pathogenesis of GISTs followed by a discussion of imatinib and sunitinib’s role in the treatment of GISTs. Finally, we will introduce novel therapeutic options for imatinib- and sunitinib-resistant GISTs.
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27
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Papaetis GS, Syrigos KN. Targeted therapy for gastrointestinal stromal tumors: current status and future perspectives. Cancer Metastasis Rev 2010; 29:151-70. [PMID: 20112054 DOI: 10.1007/s10555-010-9206-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Gastrointestinal stromal tumors (GISTs) present 80% of gastrointestinal tract mesenchymal tumors, with systemic chemotherapy and radiotherapy being unable to improve survival of patients with advanced disease. The identification of activating mutations in either KIT cell surface growth factor receptor or platelet-derived growth factor receptor alpha, which lead to ligand-independent signal transduction, paved the way for the development of novel agents that selectively inhibit key molecular events in disease pathogenesis. The development of imatinib mesylate in the treatment of metastatic GIST represents a therapeutic breakthrough in molecularly targeted strategies, which crucially improved patients' prognosis while its usefulness in adjuvant and neoadjuvant setting is under study. Sunitinib malate is available in the second-line setting, with ongoing studies evaluating its role in an earlier disease stage, while other targets are under intense investigation in order to enrich the therapeutical armamentarium for this disease. GIST phenotype seems to be an essential indicator of treatment response; thus, obtaining genotype information of each patient may be critical in order to tailor individualized treatment strategies and achieve maximal therapeutic results.
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Affiliation(s)
- Georgios S Papaetis
- Oncology Unit, 3rd Department of Medicine, Athens School of Medicine, Sotiria General Hospital, Athens, Greece.
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28
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Liu S, Wu LC, Pang J, Santhanam R, Schwind S, Wu YZ, Hickey C, Yu J, Becker H, Maharry K, Radmacher MD, Li C, Whitman SP, Mishra A, Stauffer N, Eiring AM, Briesewitz R, Baiocchi RA, Chan KK, Paschka P, Caligiuri MA, Byrd JC, Croce CM, Bloomfield CD, Perrotti D, Garzon R, Marcucci G. Sp1/NFkappaB/HDAC/miR-29b regulatory network in KIT-driven myeloid leukemia. Cancer Cell 2010; 17:333-47. [PMID: 20385359 PMCID: PMC2917066 DOI: 10.1016/j.ccr.2010.03.008] [Citation(s) in RCA: 213] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2009] [Revised: 11/29/2009] [Accepted: 03/17/2010] [Indexed: 12/29/2022]
Abstract
The biologic and clinical significance of KIT overexpression that associates with KIT gain-of-function mutations occurring in subsets of acute myeloid leukemia (AML) (i.e., core binding factor AML) is unknown. Here, we show that KIT mutations lead to MYC-dependent miR-29b repression and increased levels of the miR-29b target Sp1 in KIT-driven leukemia. Sp1 enhances its own expression by participating in a NFkappaB/HDAC complex that further represses miR-29b transcription. Upregulated Sp1 then binds NFkappaB and transactivates KIT. Therefore, activated KIT ultimately induces its own transcription. Our results provide evidence that the mechanisms of Sp1/NFkappaB/HDAC/miR-29b-dependent KIT overexpression contribute to leukemia growth and can be successfully targeted by pharmacological disruption of the Sp1/NFkappaB/HDAC complex or synthetic miR-29b treatment in KIT-driven AML.
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Affiliation(s)
- Shujun Liu
- Divisions of Hematology-Oncology, The Ohio State University, Columbus, OH 4321
- The Comprehensive Cancer Center, The Ohio State University, Columbus, OH 4321
- To whom correspondence should be addressed: Shujun Liu and Guido Marcucci, The Ohio State University, 898 Biomedical Research Tower, 460 West 12th Avenue, Columbus, Ohio 43210. Phone: 614-293-7597. FAX: 614-293-7527. or
| | - Lai-Chu Wu
- Department of Molecular & Cellular Biochemistry, The Ohio State University, Columbus, OH 4321
| | - Jiuxia Pang
- The Comprehensive Cancer Center, The Ohio State University, Columbus, OH 4321
| | - Ramasamy Santhanam
- Divisions of Hematology-Oncology, The Ohio State University, Columbus, OH 4321
- The Comprehensive Cancer Center, The Ohio State University, Columbus, OH 4321
| | - Sebastian Schwind
- Divisions of Hematology-Oncology, The Ohio State University, Columbus, OH 4321
- The Comprehensive Cancer Center, The Ohio State University, Columbus, OH 4321
| | - Yue-Zhong Wu
- Divisions of Hematology-Oncology, The Ohio State University, Columbus, OH 4321
| | - Christopher Hickey
- Divisions of Hematology-Oncology, The Ohio State University, Columbus, OH 4321
| | - Jianhua Yu
- The Comprehensive Cancer Center, The Ohio State University, Columbus, OH 4321
- Department of Molecular Virology, Immunology and Cancer Genetics, The Ohio State University, Columbus, OH 4321
| | - Heiko Becker
- Divisions of Hematology-Oncology, The Ohio State University, Columbus, OH 4321
- The Comprehensive Cancer Center, The Ohio State University, Columbus, OH 4321
| | - Kati Maharry
- Divisions of Hematology-Oncology, The Ohio State University, Columbus, OH 4321
- The Comprehensive Cancer Center, The Ohio State University, Columbus, OH 4321
| | - Michael D Radmacher
- The Comprehensive Cancer Center, The Ohio State University, Columbus, OH 4321
| | - Chenglong Li
- Department of Molecular & Cellular Biochemistry, The Ohio State University, Columbus, OH 4321
| | - Susan P. Whitman
- The Comprehensive Cancer Center, The Ohio State University, Columbus, OH 4321
- Department of Molecular Virology, Immunology and Cancer Genetics, The Ohio State University, Columbus, OH 4321
| | - Anjali Mishra
- The Comprehensive Cancer Center, The Ohio State University, Columbus, OH 4321
- Department of Molecular Virology, Immunology and Cancer Genetics, The Ohio State University, Columbus, OH 4321
| | - Nicole Stauffer
- Divisions of Hematology-Oncology, The Ohio State University, Columbus, OH 4321
- The Comprehensive Cancer Center, The Ohio State University, Columbus, OH 4321
| | - Anna M. Eiring
- Department of Molecular Virology, Immunology and Cancer Genetics, The Ohio State University, Columbus, OH 4321
| | - Roger Briesewitz
- The Comprehensive Cancer Center, The Ohio State University, Columbus, OH 4321
| | - Robert A. Baiocchi
- Divisions of Hematology-Oncology, The Ohio State University, Columbus, OH 4321
- The Comprehensive Cancer Center, The Ohio State University, Columbus, OH 4321
| | - Kenneth K. Chan
- The Comprehensive Cancer Center, The Ohio State University, Columbus, OH 4321
- Division of Pharmaceutics of College of Pharmacy, The Ohio State University, Columbus, OH 4321
| | - Peter Paschka
- Department of Internal Medicine III, University Hospital of Ulm, Ulm, Germany
| | - Michael A. Caligiuri
- Divisions of Hematology-Oncology, The Ohio State University, Columbus, OH 4321
- The Comprehensive Cancer Center, The Ohio State University, Columbus, OH 4321
- Department of Molecular Virology, Immunology and Cancer Genetics, The Ohio State University, Columbus, OH 4321
| | - John C. Byrd
- Divisions of Hematology-Oncology, The Ohio State University, Columbus, OH 4321
- The Comprehensive Cancer Center, The Ohio State University, Columbus, OH 4321
- Department of Molecular Virology, Immunology and Cancer Genetics, The Ohio State University, Columbus, OH 4321
| | - Carlo M Croce
- The Comprehensive Cancer Center, The Ohio State University, Columbus, OH 4321
- Department of Molecular Virology, Immunology and Cancer Genetics, The Ohio State University, Columbus, OH 4321
| | - Clara D. Bloomfield
- Divisions of Hematology-Oncology, The Ohio State University, Columbus, OH 4321
- The Comprehensive Cancer Center, The Ohio State University, Columbus, OH 4321
| | - Danilo Perrotti
- The Comprehensive Cancer Center, The Ohio State University, Columbus, OH 4321
- Department of Molecular Virology, Immunology and Cancer Genetics, The Ohio State University, Columbus, OH 4321
| | - Ramiro Garzon
- Divisions of Hematology-Oncology, The Ohio State University, Columbus, OH 4321
- The Comprehensive Cancer Center, The Ohio State University, Columbus, OH 4321
| | - Guido Marcucci
- Divisions of Hematology-Oncology, The Ohio State University, Columbus, OH 4321
- The Comprehensive Cancer Center, The Ohio State University, Columbus, OH 4321
- Department of Molecular Virology, Immunology and Cancer Genetics, The Ohio State University, Columbus, OH 4321
- Division of Pharmaceutics of College of Pharmacy, The Ohio State University, Columbus, OH 4321
- To whom correspondence should be addressed: Shujun Liu and Guido Marcucci, The Ohio State University, 898 Biomedical Research Tower, 460 West 12th Avenue, Columbus, Ohio 43210. Phone: 614-293-7597. FAX: 614-293-7527. or
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PET and PET/CT in gastrointestinal stromal tumours: the unanswered questions and the potential newer applications. Eur J Nucl Med Mol Imaging 2010; 37:1255-8. [DOI: 10.1007/s00259-010-1404-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2009] [Accepted: 02/03/2010] [Indexed: 12/31/2022]
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Gordon PM, Fisher DE. Role for the proapoptotic factor BIM in mediating imatinib-induced apoptosis in a c-KIT-dependent gastrointestinal stromal tumor cell line. J Biol Chem 2010; 285:14109-14. [PMID: 20231287 DOI: 10.1074/jbc.m109.078592] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The c-KIT receptor tyrosine kinase is constitutively activated and oncogenic in the majority of gastrointestinal stromal tumors. The identification of selective inhibitors of c-KIT, such as imatinib, has provided a novel therapeutic approach in the treatment of this chemotherapy refractory tumor. However, despite the clinical importance of these findings and the potential it provides as a model system for understanding targeted therapy, this approach has not yielded curative outcomes in most patients, and the biochemical pathways connecting c-KIT inhibition to cell death are not completely understood. Here, we show that inhibition of c-KIT with imatinib in gastrointestinal stromal tumors (GISTs) triggered the up-regulation of the proapoptotic protein BIM via both transcriptional and post-translational mechanisms. The inhibition of c-KIT by imatinib increased levels of the dephosphorylated and deubiquitinated form of BIM as well as triggered the accumulation of the transcription factor FOXO3a on the BIM promoter to activate transcription of BIM mRNA. Furthermore, using RNA interference directed against BIM, we demonstrated that BIM knockdown attenuated the effects of imatinib, suggesting that BIM functionally contributes to imatinib-induced apoptosis in GIST. The identification and characterization of the pathways that mediate imatinib-induced cell death in GIST provide for a better understanding of targeted therapy and may facilitate the development of new therapeutic approaches to further exploit these pathways.
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Affiliation(s)
- Peter M Gordon
- Dana-Farber Cancer Institute, Boston, Massachusetts 02115, USA
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Liegl-Atzwanger B, Fletcher JA, Fletcher CDM. Gastrointestinal stromal tumors. Virchows Arch 2010; 456:111-27. [PMID: 20165865 DOI: 10.1007/s00428-010-0891-y] [Citation(s) in RCA: 152] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2010] [Accepted: 01/29/2010] [Indexed: 12/17/2022]
Abstract
Gastrointestinal stromal tumors (GISTs) have emerged from being poorly defined, treatment-resistant tumors to a well-recognized, well-understood, and treatable tumor entity within only one decade. The understanding of GIST biology has made this tumor a paradigm for molecularly targeted therapy in solid tumors and provides informative insights into the advantages and limitations of so-called targeted therapeutics. Approximately 85% of GISTs harbor activating mutations in KIT or the homologous receptor tyrosine kinase PDGFRA gene. These mutations are an early event in GIST development and the oncoproteins serve as a target for the small molecule tyrosine kinase inhibitors imatinib and sunitinib. The existing and emerging treatment options demand exact morphologic classification and risk assessment. Although, KIT (CD117) immunohistochemistry is a reliable diagnostic tool in the diagnosis of GIST, KIT-negative GISTs, GISTs showing unusual morphology as well as GISTs which progress during or after treatment with imatinib/sunitinib can be a challenge for pathologists and clinicians. This review focuses on GIST pathogenesis, morphologic evaluation, promising new immunohistochemical markers, risk assessment, the role of molecular analysis, and the increasing problem of secondary imatinib resistance and its mechanisms.
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Jin Y, Lu Z, Cao K, Zhu Y, Chen Q, Zhu F, Qian C, Pan J. The antitumor activity of homoharringtonine against human mast cells harboring the KIT D816V mutation. Mol Cancer Ther 2010; 9:211-23. [PMID: 20053766 DOI: 10.1158/1535-7163.mct-09-0468] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Gain-of-function mutations of the receptor tyrosine kinase KIT play a critical role in the pathogenesis of systemic mastocytosis (SM) and gastrointestinal stromal tumors. The various juxtamembrane type of KIT mutations, including V560G, are found in 60% to 70% of patients with gastrointestinal stromal tumors; loop mutant D816V, which exists in approximately 80% of SM patients, is completely resistant to imatinib. In the present study, we hypothesized that homoharringtonine (HHT), a protein synthesis inhibitor, would decrease the level of KIT protein by inhibiting translation, resulting in a decreased level of phospho-KIT and abrogating its constitutive downstream signaling. Imatinib-sensitive HMC-1.1 cells harboring the mutation V560G in the juxtamembrane domain of KIT, imatinib-resistant HMC-1.2 cells harboring both V560G and D816V mutations, and murine P815 cells were treated with HHT and analyzed in terms of growth, apoptosis, and signal transduction. The in vivo antitumor activity was evaluated by using the murine mast cell leukemia model. Our results indicated that HHT effectively inhibited the growth and induced apoptosis in cells bearing both V560G and D816V or D814Y KIT. Additionally, HHT inhibited the KIT-dependent phosphorylation of downstream signaling molecules Akt, signal transducer and activator of transcription 3 and 5, and extracellular signal-regulated kinase 1/2. Furthermore, HHT significantly prolonged the survival duration of mice with aggressive SM or mast cell leukemia by inhibiting the expansion and infiltration of imatinib-resistant mast tumor cells harboring imatinib-resistant D814Y KIT. Collectively, we show that HHT circumvents D816V KIT-elicited imatinib resistance. Our findings warrant a clinical trial of HHT in patients with SM harboring D816V or D814Y KIT.
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Affiliation(s)
- Yanli Jin
- Department of Pathophysiology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, People's Republic of China
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Pan J. RNA polymerase - an important molecular target of triptolide in cancer cells. Cancer Lett 2010; 292:149-52. [PMID: 20045594 DOI: 10.1016/j.canlet.2009.11.018] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2009] [Revised: 11/26/2009] [Accepted: 11/27/2009] [Indexed: 11/19/2022]
Abstract
Triptolide, a diterpenoid triepoxide, is the key biological component of Tripterygium wilfordii Hook. f. which was used in traditional Chinese medicine for centuries to treat inflammation and autoimmune diseases. Triptolide has shown potent activity in not only anti-inflammation and immune modulation, but also antiproliferative and proapoptotic activity in many different types of cancer cells. However, for a long time, the precise molecular target(s) of triptolide have remained elusive. Recently, several groups discovered that triptolide inhibited the activity of RNA polymerase. This review will focus on these breakthrough findings about the molecular target of triptolide and its implications for targeted-cancer therapeutics.
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Affiliation(s)
- Jingxuan Pan
- Department of Pathophysiology, Zhongshan School of Medicine, Sun Yat-sen University, 74 Zhongshan Road II, Guangzhou 510089, People's Republic of China.
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Bauer S, Parry JA, Mühlenberg T, Brown MF, Seneviratne D, Chatterjee P, Chin A, Rubin BP, Kuan SF, Fletcher JA, Duensing S, Duensing A. Proapoptotic activity of bortezomib in gastrointestinal stromal tumor cells. Cancer Res 2009; 70:150-9. [PMID: 20028860 DOI: 10.1158/0008-5472.can-09-1449] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Gastrointestinal stromal tumors (GIST) are caused by activating mutations in the KIT or PDGFRA receptor tyrosine kinase genes. Although >85% of GIST patients treated with the small-molecule inhibitor imatinib mesylate (Gleevec) achieve disease stabilization, complete remissions are rare and a substantial proportion of patients develop resistance to imatinib over time. Upregulation of soluble, non-chromatin-bound histone H2AX has an important role in imatinib-induced apoptosis of GIST cells. Additionally, H2AX levels in untreated GIST are maintained at low levels by a pathway that involves KIT, phosphoinositide 3-kinase, and the ubiquitin-proteasome system. In this study, we asked whether bortezomib-mediated inhibition of the ubiquitin-proteasome machinery could lead to upregulation of histone H2AX and GIST cell death. We show that bortezomib rapidly triggers apoptosis in GIST cells through a combination of mechanisms involving H2AX upregulation and loss of KIT protein expression. Downregulation of KIT transcription was an underlying mechanism for bortezomib-mediated inhibition of KIT expression. In contrast, the nuclear factor-kappaB signaling pathway did not seem to play a major role in bortezomib-induced GIST cell death. Significantly, we found that bortezomib would induce apoptosis in two imatinib-resistant GIST cell lines as well as a short-term culture established from a primary imatinib-resistant GIST. Collectively, our results provide a rationale to test the efficacy of bortezomib in GIST patients with imatinib-sensitive or -resistant tumors.
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Affiliation(s)
- Sebastian Bauer
- Sarcoma Center, West German Cancer Center, University of Essen Medical School, Essen, Germany
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Gramza AW, Corless CL, Heinrich MC. Resistance to Tyrosine Kinase Inhibitors in Gastrointestinal Stromal Tumors. Clin Cancer Res 2009; 15:7510-7518. [PMID: 20008851 DOI: 10.1158/1078-0432.ccr-09-0190] [Citation(s) in RCA: 167] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Gastrointestinal stromal tumors (GIST) are the most common type of sarcoma in the gastrointestinal tract. Surgery is the primary treatment modality, but many patients suffer disease recurrence or metastasis. Fortunately, the management of advanced GIST has been revolutionized by the use of small molecule kinase inhibitors that target the underlying pathogenetic mutant kinases found in the vast majority of cases. Approximately 85% of GISTs have oncogenic mutations in KIT, allowing for constitutive kinase activation that is responsible for cellular proliferation and survival. About 5 to 7% of GISTs have activating mutations of the homologous platelet-derived growth factor receptor alpha (PDGFRA) kinase. The progression-free and overall survival of patients with advanced disease is greatly improved by treatment with the kinase inhibitors imatinib and sunitinib. However, the emergence of drug-resistant tumor clones limits the long-term benefit of these drugs in most patients. Resistance to these kinase inhibitors is associated with distinctive clinical and molecular features, with the development of secondary mutations of the oncogenic kinase being the most common mechanism. We review the molecular basis of GIST response and/or resistance to TKIs, and discuss strategies to prevent and/or overcome drug resistance. These concepts are directly relevant to the development of targeted molecular therapy for other solid tumors. (Clin Cancer Res 2009;15(24):7510-8).
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Affiliation(s)
- Ann W Gramza
- Authors' Affiliations: Portland VA Medical Center and Oregon Health and Science University Knight Cancer Institute, Portland, Oregon
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Jin Y, Chen Q, Lu Z, Chen B, Pan J. Triptolide abrogates oncogene FIP1L1-PDGFRalpha addiction and induces apoptosis in hypereosinophilic syndrome. Cancer Sci 2009; 100:2210-7. [PMID: 19671059 PMCID: PMC11159907 DOI: 10.1111/j.1349-7006.2009.01283.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2009] [Revised: 06/27/2009] [Accepted: 07/03/2009] [Indexed: 11/27/2022] Open
Abstract
The pathogenesis of hypereosinophilic syndrome (HES) in some patients is highly dependent on FIP1-Like-1 (FIP1L1)-platelet-derived growth factor receptor alpha (PDGFRalpha), which can generate sustained activation signaling to maintain a cell malignant phenotype. HES usually shows good response to the tyrosine kinase inhibitor imatinib, but mutations in FIP1L1-PDGFRalpha (e.g. T674I) can confer acquired resistance to imatinib. An alternative therapeutic strategy other than with tyrosine kinase inhibitors is needed to overcome acquired drug resistance. We hypothesized that switching off the crucial chimeric oncoprotein FIP1L1-PDGFRalpha on which HES cells depend, should have deleterious effects on the cancer cells. We used low concentrations of triptolide, a transcription inhibitor, to shut down the expression of FIP1L1-PDGFRalpha. EOL-1 cells and BaF3 cells expressing wild-type or T674I FIP1L1-PDGFRalpha were treated with triptolide, and signaling pathways, cell cycling, and apoptosis were analyzed by RT-PCR, immunoblotting, and flow cytometry, respectively. The results revealed that at nanomolar concentrations triptolide decreased the levels of mRNA and protein of FIP1L1-PDGFRalpha and the growth of the neoplastic cells, regardless of the mutational status of PDGFRalpha. Triptolide also downregulated the signaling molecules Stat3, Akt, and Erk1/2, which are downstream from PDGFRalpha, and induced G1 cell-cycle arrest. Triptolide time- and dose-dependently induced apoptosis by decreasing the anti-apoptotic proteins Mcl-1 and Bcl-X(L),triggering the intrinsic apoptotic pathway. In conclusion, triptolide has potent activity against malignant cells in HES bearing FIP1L1-PDGFRalpha, regardless of its mutational status that confer acquired resistance to imatinib. Our results suggest that triptolide may be a promising agent in the treatment of HES.
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Affiliation(s)
- Yanli Jin
- Department of Pathophysiology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
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Affiliation(s)
- Maureen J O'Sullivan
- Consultant Paediatric Pathologist, Our Lady's Children's Hospital, Crumlin, Dublin 12, Ireland.
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Abstract
GIST (gastrointestinal stromal tumor) is a rare soft tissue malignancy arising in the gut. It has become well known recently because of the effectiveness of anti-KIT tyrosine kinase inhibitors. From a disease that 10 years ago was only treatable with surgery, now multiple phase 2 and phase 3 trials have identified active first-line systemic therapy, appropriate dosing, an active second-line agent, and established the role of adjuvant therapy after surgery for patients with intermediate- and high-risk tumors. These are accomplishments that took decades to achieve for other more common diseases such as breast cancer or lung cancer. GIST has been the ideal disease system for studying targeted therapy in solid tumors. The progress in treating GIST has come directly from the advances that have been made in the laboratory, understanding the basic biology of tyrosine kinases, the oncogenic activity of c-KIT, and how that enzymatic activity can be inhibited. By studying model diseases such as GIST, we should be able to develop paradigms to treat more common cancers as well.
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Affiliation(s)
- David D'Adamo
- Memorial Sloan Kettering Cancer Center, New York, NY, USA.
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Jin Y, Chen Q, Shi X, Lu Z, Cheng C, Lai Y, Zheng Q, Pan J. Activity of triptolide against human mast cells harboring the kinase domain mutant KIT. Cancer Sci 2009; 100:1335-43. [PMID: 19383029 PMCID: PMC11159779 DOI: 10.1111/j.1349-7006.2009.01159.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2008] [Revised: 02/17/2009] [Accepted: 03/04/2009] [Indexed: 01/18/2023] Open
Abstract
Gain-of-function mutations of the receptor tyrosine kinase KIT can cause systemic mastocytosis (SM) and gastrointestinal stromal tumors. Most of the constitutively active KIT can be inhibited by imatinib; D816V KIT cannot. In this study, we investigated the activity of triptolide, a diterpenoid isolated from the Chinese herb Tripterygium wilfordii Hook. f., in cells expressing mutant KIT, including D816V KIT. Imatinib-sensitive HMC-1.1 cells harboring the mutation V560G in the juxtamembrane domain of KIT, imatinib-resistant HMC-1.2 cells harboring both V560G and D816V mutations, and murine P815 cells, were treated with triptolide, and analyzed in terms of growth, apoptosis, and signal transduction. The in vivo antitumor activity was evaluated by using the nude mouse xenograft model. Our results demonstrated that triptolide potently inhibits the growth of both human and murine mast cells harboring not only imatinib-sensitive KIT mutation but also imatinib-resistant D816V KIT. Triptolide markedly inhibited KIT mRNA levels and strikingly reduced the levels of phosphorylated and total Stat3, Akt, and Erk1/2, downstream targets of KIT. Triptolide triggered apoptosis by inducing depolarization of mitochondrial potential and release of cytochrome c, downregulation of Mcl-1 and XIAP. Furthermore, triptolide significantly abrogated the growth of imatinib-resistant HMC-1.2 cell xenografts in nude mice and decreased KIT expression in xenografts. Our data demonstrate that triptolide inhibits imatinib-resistant mast cells harboring D816V KIT. Further investigation of triptolide for treatment of human neoplasms driven by gain-of-function KIT mutations is warranted.
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Affiliation(s)
- Yanli Jin
- Department of Pathophysiology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
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Bonvini P, Zorzi E, Mussolin L, Monaco G, Pigazzi M, Basso G, Rosolen A. The effect of the cyclin-dependent kinase inhibitor flavopiridol on anaplastic large cell lymphoma cells and relationship with NPM-ALK kinase expression and activity. Haematologica 2009; 94:944-55. [PMID: 19535344 DOI: 10.3324/haematol.2008.004861] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
BACKGROUND The loss of cell cycle regulation due to abnormal function of cyclin-dependent kinases (cdk) occurs in tumors and leads to genetic instability of chemotherapy-resistant cells. In this study, we investigated the effect of the cdk inhibitor flavopiridol in anaplastic large cell lymphomas, in which unrestrained proliferation depends on NPM-ALK tyrosine kinase activity. DESIGN AND METHODS Effects of flavopiridol were examined in ALK-positive and -negative anaplastic large cell lymphoma cells by means of immunoblotting and immunofluorescence analyses to assess cdk expression and activity, quantitative real time reverse transcriptase polymerase chain reaction to measure drug-induced changes in transcription, and FACS analyses to monitor changes in proliferation and survival. RESULTS Treatment with flavopiridol resulted in growth inhibition of anaplastic large cell lymphoma cells, along with accumulation of subG(1) cells and disappearance of S phase without cell cycle arrest. Consistent with flavopiridol activity, phosphorylation at cdk2, cdk4, cdk9 sites on RB and RNA polymerase II was inhibited. This correlated with induction of cell death through rapid mitochondrial damage, inhibition of DNA synthesis, and down-regulation of anti-apoptotic proteins and transcripts. Notably, flavopiridol was less active in ALK-positive cells, as apoptosis was observed at higher concentrations and later time points, and resistance to treatment was observed in cells maintaining NPM-ALK signaling. NPM-ALK inhibition affected proliferation but not survival of anaplastic large cell lym-phoma cells, whereas it resulted in a dramatic increase in apoptosis when combined with flavopiridol. CONCLUSIONS This work provides the first demonstration that targeting cdk is effective against anaplastic large cell lymphoma cells, and proves the critical role of NPM-ALK in the regulation of responsiveness of tumor cells with cdk dysregulation.
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Affiliation(s)
- Paolo Bonvini
- Clinica di Oncoematologia Pediatrica, Azienda Ospedaliera-Università di Padova, 35128 Padova, Italy.
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Kurokawa T, He G, Siddik ZH. Protein kinase inhibitors emodin and dichloro-ribofuranosylbenzimidazole modulate the cellular accumulation and cytotoxicity of cisplatin in a schedule-dependent manner. Cancer Chemother Pharmacol 2009; 65:427-36. [PMID: 19529937 DOI: 10.1007/s00280-009-1045-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2008] [Accepted: 05/26/2009] [Indexed: 01/29/2023]
Abstract
PURPOSE Protein kinase inhibitors (PKI) have become prominent agents in cancer therapeutics. However, the specificity for target kinase inhibition can be poor and unwanted effects can emerge in combination regimens. The PKI emodin, for instance, can produce mixed results when combined with cisplatin, and we have sought a biochemical pharmacologic explanation for the negative cytotoxic effects. METHODS Human ovarian A2780 tumor cells were exposed to the PKI emodin or dichloro-ribofuranosylbenzimidazole (DRB) with cisplatin using several schedules, and cytotoxicity determined by a growth inhibition assay. Intracellular platinum levels and DNA adducts were estimated by flameless atomic absorption spectrophotometry. RESULTS When A2780 cells were exposed first to emodin or DRB and then to cisplatin alone, the cytotoxic effects of cisplatin were significantly enhanced, whereas simultaneous exposure did not enhance the cytotoxicity, but instead inhibited it in the case of DRB. The increase in activity of cisplatin in the sequenced schedule was not due to increases in intracellular levels of cisplatin or DNA adducts, whereas the cytotoxic inhibition was related to a significant fall in both intracellular platinum levels and DNA adducts, which were ascribed to inhibition in cisplatin uptake. Knockdown of hCtr1 (the human copper transporter 1) by siRNA abrogated this inhibition in cisplatin uptake. CONCLUSION The results demonstrate that co-exposure of tumor cells to emodin or DRB with cisplatin inhibits platinum drug uptake by impacting the hCtr1 transporter and, thereby, reduce the cytotoxicity of cisplatin. Based on our findings, scheduling of the PKI and the cytotoxic agent should be a major consideration in the clinical design of combination regimens.
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Affiliation(s)
- Tetsuji Kurokawa
- Department of Experimental Therapeutics, The University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Blvd., Box 353, Houston, TX 77030, USA
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Nilsson B, Nilsson O, Ahlman H. Treatment of gastrointestinal stromal tumours: imatinib, sunitinib – and then? Expert Opin Investig Drugs 2009; 18:457-68. [DOI: 10.1517/13543780902806400] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Bengt Nilsson
- Sahlgrenska University Hospital, Department of Surgery, S-413 45 Göteborg, Sweden
| | - Ola Nilsson
- Institute of Biomedicine, Department of Pathology, S-41345 Göteborg, Sweden
| | - Håkan Ahlman
- Göteborg University, Department of Surgery, S-41345 Göteborg, Sweden
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Monoclonal antibody DOG1.1 shows higher sensitivity than KIT in the diagnosis of gastrointestinal stromal tumors, including unusual subtypes. Am J Surg Pathol 2009; 33:437-46. [PMID: 19011564 DOI: 10.1097/pas.0b013e318186b158] [Citation(s) in RCA: 184] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors in the gastrointestinal tract. Approximately 85% of GISTs harbor activating mutations in the KIT or platelet-derived growth factor receptor alpha (PDGFRA) gene and approximately 95% of GISTs are positive for KIT (CD117) by immunohistochemistry. Nevertheless, approximately 5% of GISTs lack KIT expression. Inhibition of KIT and PDGFRA by tyrosine kinase inhibitors has revolutionized the treatment of GISTs and demands accurate tumor classification. DOG1.1 is a recently described mouse monoclonal antibody reported to have superior sensitivity and specificity compared with KIT (CD117) and CD34. We evaluated this new antibody on a group of 81 GISTs obtained from 74 patients with special regard to KIT-negative GISTs (n=28), pediatric GISTs (n=11), and GISTs associated with neurofibromatosis type I (NF1) (n=16). Conventional GISTs (n=26) were also included. All conventional KIT-positive GISTs, all NF1-associated GISTs, and 9/11 pediatric GISTs expressed DOG1.1. DOG1.1 was expressed in 10/28 (36%) of KIT-negative tumors. The staining pattern was cytoplasmic and/or membranous. This study demonstrates that DOG1.1 is a sensitive immunohistochemical marker for GIST, comparable with KIT, with the additional benefit of detecting 36% of KIT-negative GISTs. DOG1.1 is also a sensitive marker for unusual GIST subgroups lacking KIT or PDGFRA mutations. In tumors that are negative for both KIT and DOG1.1, mutational screening may be required to confirm the diagnosis of GIST.
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Abstract
Gastrointestinal stromal tumors (GISTs) generally arise from primary activating mutations in the KIT or PDGFRA genes that result in constitutive activation of receptor tyrosine kinase activity. Imatinib provides targeted therapy for GIST by inhibiting the KIT and PDGFR-alpha tyrosine kinases. Clinical benefit is achieved in approximately 85% of patients with unresectable or metastatic disease, with a median progression-free survival of 20 to 24 months. The mechanisms of acquired resistance to imatinib are heterogeneous, with most involving the emergence of secondary mutations in KIT exons 13, 14, or 17. In patients failing or intolerant to imatinib, the multitargeted agent sunitinib achieves durable disease control in approximately 50% of cases. Experimental treatment options beyond those currently available consist of other KIT-targeting tyrosine kinase inhibitors, such as nilotinib, or agents targeting alternative pathways, such as antiangiogenic agents, mammalian target of rapamycin, RAF kinase, and chaperone inhibitors.
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Affiliation(s)
- Peter Reichardt
- Helios Klinikum Bad Saarow, Department of Hematology, Oncology, and Palliative Care, Sarcoma Center Berlin-Brandenburg, Pieskower Strasse 33, 15526 Bad Saarow, Germany.
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Kitamura Y. Gastrointestinal stromal tumors: past, present, and future. J Gastroenterol 2008; 43:499-508. [PMID: 18648736 DOI: 10.1007/s00535-008-2200-y] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2008] [Accepted: 04/08/2008] [Indexed: 02/06/2023]
Abstract
Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract. The name "GIST" was proposed in 1983, but the cell origin of GIST remained unclear until 1998, when my colleagues and I reported immunohistochemical evidence that GIST originated from interstitial cells of Cajal or their precursors. At the same time, we reported gain-of-function mutations of the Kit gene in GISTs. The Kit gene encodes KIT receptor tyrosine kinase, whose structure is similar to that of platelet-derived growth factor receptor (PDGFR). Imatinib mesylate was initially developed as an inhibitor of PDGFR. Then, it was found to be a potent inhibitor of BCR-ABL. Imatinib was successfully used for the treatment of chronic myeloid leukemia. When we reported gain-of-function mutations of the Kit gene in GISTs, the inhibitory effect of imatinib on KIT was already known. Imatinib was then successfully applied to the treatment of GISTs. The interrelationship between the type of Kit gain-of-function mutation and the therapeutic effect of imatinib has been well characterized in GISTs. Although various mutations of Kit and Pdgfr-alpha genes have been found in GISTs, most GISTs are luckily imatinibsensitive. After long-term administration of imatinib, however, new imatinib-resistant clones develop a secondary mutation of the Kit or Pdgfr-alpha gene. New drugs and adjuvant regimens against such secondary progression are now being intensively explored.
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Affiliation(s)
- Yukihiko Kitamura
- Developmental Research Laboratories, Shionogi & Co. Ltd., 3-1-1 Futaba-cho, Toyonaka 561-0825, Japan
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Teillet F, Boumendjel A, Boutonnat J, Ronot X. Flavonoids as RTK inhibitors and potential anticancer agents. Med Res Rev 2008; 28:715-45. [PMID: 18080331 DOI: 10.1002/med.20122] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Tyrosine kinase receptors (RTKs) play a crucial role in the regulation of the cell division cycle. Currently more than 50 RTKs divided into several subfamilies have been described. The inhibition of these enzymes has emerged as an important research-area. Compounds able to inhibit the activity of these enzymes are expected to display antiproliferative properties. Flavonoids are representative of various small molecules acting as RTK inhibitors. These naturally occurring compounds are able to bind to the ATP-binding site of several kinases. The most plausible current hypothesis explaining the action of these substances on kinases is that the chromenone moiety of the flavonoid acts as a mimetic of the adenine moiety of ATP, the receptor co-factor. In this review, we report recent results on the activity of natural and synthetic derivatives of flavonoids as inhibitors of RTKs. Mechanistic aspects, the therapeutic usefulness, and the potential clinical use are discussed.
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Affiliation(s)
- Florence Teillet
- Laboratoire de Dynamique Cellulaire, EPHE, Laboratoire TIMC-IMAG, UMR-CNRS 5525, Université Joseph Fourier, Pavillon Taillefer, 38706 La Tronche Cedex, France
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The structure of P-TEFb (CDK9/cyclin T1), its complex with flavopiridol and regulation by phosphorylation. EMBO J 2008; 27:1907-18. [PMID: 18566585 DOI: 10.1038/emboj.2008.121] [Citation(s) in RCA: 264] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2008] [Accepted: 05/28/2008] [Indexed: 11/09/2022] Open
Abstract
The positive transcription elongation factor b (P-TEFb) (CDK9/cyclin T (CycT)) promotes mRNA transcriptional elongation through phosphorylation of elongation repressors and RNA polymerase II. To understand the regulation of a transcriptional CDK by its cognate cyclin, we have determined the structures of the CDK9/CycT1 and free cyclin T2. There are distinct differences between CDK9/CycT1 and the cell cycle CDK CDK2/CycA manifested by a relative rotation of 26 degrees of CycT1 with respect to the CDK, showing for the first time plasticity in CDK cyclin interactions. The CDK9/CycT1 interface is relatively sparse but retains some core CDK-cyclin interactions. The CycT1 C-terminal helix shows flexibility that may be important for the interaction of this region with HIV TAT and HEXIM. Flavopiridol, an anticancer drug in phase II clinical trials, binds to the ATP site of CDK9 inducing unanticipated structural changes that bury the inhibitor. CDK9 activity and recognition of regulatory proteins are governed by autophosphorylation. We show that CDK9/CycT1 autophosphorylates on Thr186 in the activation segment and three C-terminal phosphorylation sites. Autophosphorylation on all sites occurs in cis.
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Ambrosini G, Seelman SL, Qin LX, Schwartz GK. The Cyclin-Dependent Kinase Inhibitor Flavopiridol Potentiates the Effects of Topoisomerase I Poisons by Suppressing Rad51 Expression in a p53-Dependent Manner. Cancer Res 2008; 68:2312-20. [DOI: 10.1158/0008-5472.can-07-2395] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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