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Synergistic targeted therapy for acute promyelocytic leukaemia: a model of translational research in human cancer.
Mi, JQ, Chen, SJ, Zhou, GB, Yan, XJ, Chen, Z
Journal of internal medicine. 2015;(6):627-42
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Abstract
Acute promyelocytic leukaemia (APL), the M3 subtype of acute myeloid leukaemia, was once a lethal disease, yet nowadays the majority of patients with APL can be successfully cured by molecularly targeted therapy. This dramatic improvement in the survival rate is an example of the advantage of modern medicine. APL is characterized by a balanced reciprocal chromosomal translocation fusing the promyelocytic leukaemia (PML) gene on chromosome 15 with the retinoic acid receptor α (RARα) gene on chromosome 17. It has been found that all-trans-retinoic acid (ATRA) or arsenic trioxide (ATO) alone exerts therapeutic effect on APL patients with the PML-RARα fusion gene, and the combination of both drugs can act synergistically to further enhance the cure rate of the patients. Here, we provide an insight into the pathogenesis of APL and the mechanisms underlying the respective roles of ATRA and ATO. In addition, treatments that lead to more effective differentiation and apoptosis of APL cells, including leukaemia-initiating cells, and more thorough eradication of the disease will be discussed. Moreover, as a model of translational research, the development of a cure for APL has followed a bidirectional approach of 'bench to bedside' and 'bedside to bench', which can serve as a valuable example for the diagnosis and treatment of other malignancies.
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[Relationship between Arsenic (+3 Oxidation State) Methyltransferase Genetic Polymorphisms and Methylation Capacity of Inorganic Arsenic].
Agusa, T, Kunito, T, Minh Tue, N, Thi Mai Lan, V, Binh Minh, T, Thi Kim Trang, P, Fujihara, J, Takeshita, H, Takahashi, S, Hung Viet, P, et al
Nihon eiseigaku zasshi. Japanese journal of hygiene. 2015;(3):186-96
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Abstract
Arsenic metabolism affects the susceptibility of humans to arsenic toxicity; therefore, clarification of the factors associated with individual variations in arsenic metabolism is an important task. Genetic polymorphisms such as single nucleotide polymorphisms (SNPs) in arsenic (+3 oxidation state) methyltransferase (AS3MT), which can methylate arsenic compounds using S-adenosyl-l-methionine (AdoMet), have been reported to modify arsenic methylation. In this review, we summarize studies conducted by us in Vietnam and by others on the association of AS3MT genetic polymorphisms with arsenic metabolism as well as human health effects. Most of the SNPs in AS3MT showed inconsistent results in terms of genotype-dependent differences in arsenic metabolism among the studies. However, AS3MT 12390 (rs3740393) and 14458 (rs11191439) were consistently related to arsenic methylation regardless of the study population: AS3MT 12390 (rs3740393) affected the second step of methylation of arsenic, whereas 14458 (rs11191439) affected the first methylation step.
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Physical, chemical, and biological methods for the removal of arsenic compounds.
Lim, KT, Shukor, MY, Wasoh, H
BioMed research international. 2014;:503784
Abstract
Arsenic is a toxic metalloid which is widely distributed in nature. It is normally present as arsenate under oxic conditions while arsenite is predominant under reducing condition. The major discharges of arsenic in the environment are mainly due to natural sources such as aquifers and anthropogenic sources. It is known that arsenite salts are more toxic than arsenate as it binds with vicinal thiols in pyruvate dehydrogenase while arsenate inhibits the oxidative phosphorylation process. The common mechanisms for arsenic detoxification are uptaken by phosphate transporters, aquaglyceroporins, and active extrusion system and reduced by arsenate reductases via dissimilatory reduction mechanism. Some species of autotrophic and heterotrophic microorganisms use arsenic oxyanions for their regeneration of energy. Certain species of microorganisms are able to use arsenate as their nutrient in respiratory process. Detoxification operons are a common form of arsenic resistance in microorganisms. Hence, the use of bioremediation could be an effective and economic way to reduce this pollutant from the environment.
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Contemporary treatment of APL.
Cull, EH, Altman, JK
Current hematologic malignancy reports. 2014;(2):193-201
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Abstract
Acute promyelocytic leukemia (APL) is characterized by coagulopathy, leukopenic presentation and sensitivity to anthracyclines, all-trans retinoic acid (ATRA) and arsenic trioxide (ATO). For the last 25 years, APL has been treated with a combination of ATRA and chemotherapy for induction followed by consolidation and maintenance therapy. This general treatment approach has resulted in cure rates of 80-90 %. ATO, originally approved in relapsed APL, has been incorporated into contemporary upfront treatment regimens with excellent response rates. Recent studies show that most patients with APL can be cured with ATRA and ATO alone, eliminating cytotoxic chemotherapy and resulting in superior outcomes compared to standard treatment. We will herein review historical treatment of APL, treatment considerations in specific patient populations, and therapeutic updates.
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New strategies in acute promyelocytic leukemia: moving to an entirely oral, chemotherapy-free upfront management approach.
Zeidan, AM, Gore, SD
Clinical cancer research : an official journal of the American Association for Cancer Research. 2014;(19):4985-93
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Abstract
Incorporation of all-trans retinoic acid (ATRA) and arsenic trioxide (ATO) into the management paradigms of acute promyelocytic leukemia (APL) has markedly improved outcomes. Significant progress occurred in understanding the molecular pathogenesis of APL. ATO, in contrast with ATRA, is capable of eradicating the APL-initiating cells and can result in cure. Preclinical and clinical data confirmed the synergy of ATO and ATRA, and the ATRA-ATO combination was proved noninferior to a standard ATRA-chemotherapy regimen in patients with non-high-risk APL. Oral formulations of arsenic exhibited excellent activity in advanced clinical testing and their combinations with ATRA offer an opportunity for a completely oral, chemotherapy-free regimen for curing APL. Nonetheless, significant challenges remain. Reducing early death due to bleeding complications is an important area of unmet need. Data suggest that delays in initiation of ATRA upon suspecting APL continue to occur in the community and contribute to early mortality. Questions remain about the optimal place and schedule of arsenic in the therapeutic sequence and the role of the oral formulations. Refining the role of minimal residual disease in directing treatment decisions is important. Development of novel targeted agents to treat relapsed disease requires deeper understanding of the secondary resistance mechanisms to ATRA and ATO.
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[Arsenic trioxide: impact on the growth and differentiation of cancer cells and possible use in cancer therapy].
Hoffman, E, Mielicki, WP
Postepy higieny i medycyny doswiadczalnej (Online). 2013;:817-27
Abstract
Arsenic trioxide (As₂O₃) has recently been identified as an effective drug in different types of cancer therapy. It is a useful pharmacological agent in acute promyelocytic leukemia (APL) treatment, especially the form that is resistant to conventional chemotherapy with all-trans retinoic acid (ATRA). What is more, laboratory data suggest that As₂O₃ is also active when it comes to several solid tumor cell lines. However, the mechanism of action is not fully understood. As₂O₃ in high doses triggers apoptosis, while in lower concentrations it induces partial differentiation. The As₂O₃ mechanism of action involves effects on mitochondrial transmembrane potential which lead to apoptosis. It also acts on the activity of JNK kinase, glutathione, caspases, NF-ĸB nuclear factor or pro- and antiapoptotic proteins. This publication presents the current knowledge about the influence of arsenic trioxide in cancer cells.
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Targeted therapy: The new lease on life for acute promyelocytic leukemia, and beyond.
Chen, SJ, Zhou, GB
IUBMB life. 2012;(8):671-5
Abstract
Leukemia, a group of hematological malignancies characterized by abnormal proliferation, decreased apoptosis, and blocked differentiation of hematopoietic stem/progenitor cells, is a disease involving dynamic change in the genome. Chromosomal translocation and point mutation are the major mechanisms in leukemia, which lead to production of oncogenes with dominant gain of function and tumor suppressor genes with recessive loss of function. Targeted therapy refers to treatment strategies perturbing the molecules critical for leukemia pathogenesis. The t(15;17) which generates PML-RARα, t(8;21) that produces AML1-ETO, and t(9;22) which generates BCR-ABL are the three most frequently seen chromosomal translocations in myeloid leukemia. The past two to three decades have witnessed tremendous success in development of targeted therapies for acute and chronic myeloid leukemia caused by the three fusion proteins. Here, we review the therapeutic efficacies and the mechanisms of action of targeted therapies for myeloid leukemia and show how this strategy significantly improve the clinical outcome of patients and even turn acute promyelocytic leukemia from highly fatal to highly curable.
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Acute promyelocytic leukemia can be treated successfully without cytotoxic chemotherapy.
Ravandi, F
Oncology (Williston Park, N.Y.). 2011;(8):741-3
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Treatment of acute promyelocytic leukaemia with all-trans retinoic acid and arsenic trioxide: a paradigm of synergistic molecular targeting therapy.
Zhou, GB, Zhang, J, Wang, ZY, Chen, SJ, Chen, Z
Philosophical transactions of the Royal Society of London. Series B, Biological sciences. 2007;(1482):959-71
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Abstract
To turn a disease from highly fatal to highly curable is extremely difficult, especially when the disease is a type of cancer. However, we can gain some insight into how this can be done by looking back over the 50-year history of taming acute promyelocytic leukaemia (APL). APL is the M3 type of acute myeloid leukaemia characterized by an accumulation of abnormal promyelocytes in bone marrow, a severe bleeding tendency and the presence of the chromosomal translocation t(15;17) or variants. APL was considered the most fatal type of acute leukaemia five decades ago and the treatment of APL was a nightmare for physicians. Great efforts have been made by scientists worldwide to conquer this disease. The first use of chemotherapy (CT) was unsuccessful due to lack of supportive care and cytotoxic-agent-related exacerbated coagulopathy. The first breakthrough came from the use of anthracyclines which improved the complete remission (CR) rate, though the 5-year overall survival could only be attained in a small proportion of patients. A rational and intriguing hypothesis, to induce differentiation of APL cells rather than killing them, was raised in the 1970s. Laudably, the use of all-trans retinoic acid (ATRA) in treating APL resulted in terminal differentiation of APL cells and a 90-95% CR rate of patients, turning differentiation therapy in cancer treatment from hypothesis to practice. The combination of ATRA with CT further improved the 5-year overall survival. When arsenic trioxide (ATO) was used to treat relapsed APL not only the patients but also the ancient drug were revived. ATO exerts dose-dependent dual effects on APL cells: at low concentration, ATO induces partial differentiation, while at relatively high concentration, it triggers apoptosis. Of note, both ATRA and ATO trigger catabolism of the PML-RARalpha fusion protein which is the key player in APL leukaemogenesis generated from t(15;17), targeting the RARalpha (retinoic acid receptor alpha) or promyelocytic leukaemia (PML) moieties, respectively. Hence, in treating APL both ATRA and ATO represent paradigms for molecularly targeted therapy. At molecular level, ATRA and ATO synergistically modulate multiple downstream pathways/cascades. Strikingly, a clearance of PML-RARalpha transcript in an earlier and more thorough manner, and a higher quality remission and survival in newly diagnosed APL are achieved when ATRA is combined with ATO, as compared to either monotherapy, making APL a curable disease. Thus, the story of APL can serve as a model for the development of curative approaches for disease; it suggests that molecularly synergistic targeted therapies are powerful tools in cancer, and dissection of disease pathogenesis or anatomy of the cancer genome is critical in developing molecular target-based therapies.
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Relationship between cytokines and leukocytosis in patients with APL induced by all-trans retinoic acid or arsenic trioxide.
Bi, KH, Jiang, GS
Cellular & molecular immunology. 2006;(6):421-7
Abstract
Leukocytosis or hyperleukocytosis occurs during ATRA or arsenic trioxide differentiation therapy, which is related to the RA syndrome. The number of WBC often increased by ten or more times as high as that of pretreatment, around 7 to 20 days after treatment with ATRA or arsenic trioxide. Usually, when number of WBC tended to peak, there was concomitance with down-regulation of promyelocytes, up-regulation of myelocytes and more mature neutrophils. The same trend of classification of BM was observed in most of the patients with APL to whom leukocytosis happened. Although the mechanism of leukocytosis has not been demonstrated clearly, so far the proliferation hypothesis by cytokines and rheological hypothesis by adhesion molecules were taken into consideration. Otherwise, hypothesis about more divisions of differentiated myelocytes induced by ATRA or arsenic trioxide remains unclear. Usually, this kind of leukocytosis or hyperleukocytosis itself requires no additional cytotoxic treatment.