Author
Sai-Juan Chen
Other affiliations: Harbin Medical University
Bio: Sai-Juan Chen is an academic researcher from Ruijin Hospital. The author has contributed to research in topics: Acute promyelocytic leukemia & Arsenic trioxide. The author has an hindex of 17, co-authored 33 publications receiving 2837 citations. Previous affiliations of Sai-Juan Chen include Harbin Medical University.
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TL;DR: As2O3 treatment is an effective and relatively safe drug in APL patients refractory to ATRA and conventional chemotherapy, and Pharmacokinetic studies showed that after a peak level of 5.54 micromol/L, plasma arsenic was rapidly eliminated, and the continuous administration of As2O2 did not alter its pharmacokinetic behaviors.
1,398 citations
TL;DR: The results encouraged us to hypothesize that As2O3 induces APL cell differentiation through direct or indirect activation of retinoic acid receptor-related signaling pathway(s), while ΔΨm collapse is the common mechanism of As 2O3-induced apoptosis.
Abstract: Recent studies showed that arsenic trioxide (As2O3) could induce apoptosis and partial differentiation of leukemic promyelocytes. Here, we addressed the possible mechanisms underlying these two different effects. 1.0 microM As2O3-induced apoptosis was associated with condensation of the mitochondrial matrix, disruption of mitochondrial transmembrane potentials (DeltaPsim) and activation of caspase-3 in acute promyelocytic leukemia (APL) cells regardless of their sensitivity to all-trans retinoic acid (ATRA). All these effects were inhibited by dithiothreitol (DTT) and enhanced by buthionine sulfoximine (BSO). Furthermore, BSO could also render HL60 and U937 cells, which had the higher cellular catalase activity, sensitive to As2O3-induced apoptosis. Surprisingly, 1.0 microM As2O3 did not induce the DeltaPsim collapse and apoptosis, while 0.1 microM As2O3 induced partial differentiation of fresh BM cells from a de novo APL patient. In this study, we also showed that 0.2 mM DTT did not block low-dose As2O3-induced NB4 cell differentiation, and 0. 10.5 microM As2O3 did not induce differentiation of ATRA-resistant NB4-derived sublines, which were confirmed by cytomorphology, expression of CD11b, CD33 and CD14 as well as NBT reduction. Another interesting finding was that 0.10.5 microM As2O3 could also induce differentiation-related changes in ATRA-sensitive HL60 cells. However, the differentiation-inducing effect could not be seen in ATRA-resistant HL60 sublines with RARalpha mutation. Moreover, low-dose As2O3 and ATRA yielded similar gene expression profiles in APL cells. These results encouraged us to hypothesize that As2O3 induces APL cell differentiation through direct or indirect activation of retinoic acid receptor-related signaling pathway(s), while DeltaPsim collapse is the common mechanism of As2O3-induced apoptosis.
250 citations
TL;DR: Molecular studies showed rearrangements of the retinoic acid receptor alpha (RAR alpha) gene but no rearrangement of the promyelocytic leukemia gene consistent with the cytogenetic data.
Abstract: Cytogenetic study of a patient with acute promyelocytic leukemia (APL) showed an unusual karyotype 46,xy,t(11;17) (q23;21) without apparent rearrangement of chromosome 15. Molecular studies showed rearrangements of the retinoic acid receptor alpha (RAR alpha) gene but no rearrangement of the promyelocytic leukemia gene consistent with the cytogenetic data. Similar to t(15;17) APL, all-trans retinoic acid treatment in this patient produced an early leukocytosis which was followed by a myeloid maturation, but the patient died too early to achieve remission. Further molecular analysis of this patient showed a rearrangement between the RAR alpha gene and a newly discovered zinc finger gene named PLZF (promyelocytic leukemia zinc finger). The fusion PLZF-RAR alpha gene found in this case, was not found in DNA obtained from the bone marrow of normals, APL with t(15;17) and in one patient with AML-M2 with a t(11;17). Fluorescence in situ hybridization using a PLZF specific probe localized the PLZF gene to chromosomal band 11q23.1. Partial exon/intron structure of the PLZF gene flanking the break point on chromosome 11 was also established and the breakpoint within the RAR alpha gene was mapped approximately 2 kb downstream of the exon encoding the 5' untranslated region and the unique A2 domain of the RAR alpha 2 isoform.
219 citations
TL;DR: Interestingly, As2O3 over a wide range of concentration induces degradation of a key leukemogenic protein, PML–RARα, as well as the wild-type PML, thus setting up a good example of targeting therapy for human cancers.
Abstract: Acute promyelocytic leukemia (APL) is an interesting model in cancer research, because it can respond to the differentiation/apoptosis induction therapy using all-trans retinoic acid (ATRA) and arsenic trioxide (As(2)O(3)). Over the past 5 years, it has been well demonstrated that As(2)O(3) induces a high complete remission (CR) rate in both primary and relapsed APL patients (around 85 to 90%). The side effects are mild to moderate in relapsed patients, while severe hepatic lesions have been found in some primary cases. After CR obtained in relapsed patients, chemotherapy in combination with As(2)O(3) as post-remission therapy has given better survival than those treated with As(2)O(3) alone. The effect of As(2)O(3) has been shown to be related to the expression of APL-specific PML-RARalpha oncoprotein, and there is a synergistic effect between As(2)O(3) and ATRA in an APL mouse model. Cell biology studies have revealed that As(2)O(3) exerts dose-dependent dual effects on APL cells. Apoptosis is evident when cells are treated with 0.5 approximately 2.0 microM of As(2)O(3) while partial differentiation is observed using low concentrations (0.1 approximately 0.5 microM) of the drug. The apoptosis-inducing effect is associated with the collapse of mitochondrial transmembrane potentials in a thiol-dependent manner, whereas the mechanisms underlying APL cell differentiation induced by low dose arsenic remain to be explored. Interestingly, As(2)O(3) over a wide range of concentration (0.1 approximately 2.0 microM) induces degradation of a key leukemogenic protein, PML-RARalpha, as well as the wild-type PML, thus setting up a good example of targeting therapy for human cancers.
219 citations
TL;DR: It is demonstrated that low-dose As2O3 had the same effect as the conventional dosage and the mechanism of low- dose arsenic seemed to primarily induce differentiation of APL cells.
Abstract: Twenty cases of patients with relapsed acute promyelocytic leukemia (APL) were entered into this study for evaluating the clinical efficacy and pharmacokinetics of low-dose arsenic trioxide (As2O3). As2O3 was given at a daily dose of 0.08 mg/kg intravenously for 28 days. Pharmacokinetic study was carried out in eight patients. 16/20 (80%) patients achieved CR. The occurrence of some toxic events including gastrointestinal disturbance, facial edema and cardiac toxicity seemed reduced in the low-dose group than those in the standard-dose group. Differentiation changes were observed in peripheral blood, as well as in bone marrow (BM). Pharmacokinetic study showed that the plasma concentration increased soon after administration of As2O3 with the peak values of 1.535-3.424 micromol/l. After infusion, the plasma concentration was around 0.1-0.5 micromol/l. The arsenic concentration of the plasma of BM aspirates 24 h after administration in five patients was close to the level needed for differentiation-inducing effect. The estimated 2-year OS and RFS were 61.55+/-15.79% and 49.11+/-15.09% respectively, with no difference as compared with those in patients treated with conventional dose (P = 0.2865 and 0.7146, respectively). In conclusion, we demonstrated that low-dose As2O3 had the same effect as the conventional dosage and the mechanism of low-dose arsenic seemed to primarily induce differentiation of APL cells.
142 citations
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TL;DR: ROS stress in cancer cells is reviewed, its underlying mechanisms and relationship with mitochondrial malfunction and alteration in drug sensitivity are reviewed, and new therapeutic strategies that take advantage of increased ROS in cancer Cells to enhance therapeutic activity and selectivity are suggested.
1,823 citations
TL;DR: The role of these four ABC transporter proteins in protecting tissues from a variety of toxicants is discussed and species variations in substrate specificity and tissue distribution of these transporters are addressed since these properties have implications for in vivo models of toxicity used for drug discovery and development.
1,327 citations
TL;DR: Low doses of arsenic trioxide can induce complete remissions in patients with APL who have relapsed and the clinical response is associated with incomplete cytodifferentiation and the induction of apoptosis with caspase activation in leukemic cells.
Abstract: Background Two reports from China have suggested that arsenic trioxide can induce complete remissions in patients with acute promyelocytic leukemia (APL). We evaluated this drug in patients with APL in an attempt to elucidate its mechanism of action. Methods Twelve patients with APL who had relapsed after extensive prior therapy were treated with arsenic trioxide at doses ranging from 0.06 to 0.2 mg per kilogram of body weight per day until visible leukemic cells were eliminated from the bone marrow. Bone marrow mononuclear cells were serially monitored by flow cytometry for immunophenotype, fluorescence in situ hybridization, reverse-transcription–polymerase-chain-reaction (RT-PCR) assay for PML–RAR-α fusion transcripts, and Western blot analysis for expression of the apoptosis-associated proteins caspases 1, 2, and 3. Results Of the 12 patients studied, 11 had a complete remission after treatment that lasted from 12 to 39 days (range of cumulative doses, 160 to 515 mg). Adverse effects were relatively m...
1,210 citations
TL;DR: The current understanding of the apoptotic pathways, including the extrinsic (cytoplasmic) and intrinsic (mitochondrial) pathways, and the agents being developed to target these pathways are reviewed.
Abstract: Apoptosis, or programmed cell death, is a mechanism by which cells undergo death to control cell proliferation or in response to DNA damage. The understanding of apoptosis has provided the basis for novel targeted therapies that can induce death in cancer cells or sensitize them to established cytotoxic agents and radiation therapy. These novel agents include those targeting the extrinsic pathway such as tumor necrosis factor-related apoptosis-inducing ligand receptor 1, and those targeting the intrinsic Bcl-2 family pathway such as antisense bcl-2 oligonucleotides. Many pathways and proteins control the apoptosis machinery. Examples include p53, the nuclear factor kappa B, the phosphatidylinositol 3 kinase pathway, and the ubiquitin/proteosome pathway. These can be targeted by specific modulators such as bortezomib, and mammalian target of rapamycin inhibitors such as CCI-779 and RAD 001. Because these pathways may be preferentially altered in tumor cells, there is potential for a selective effect in tumors sparing normal tissue. This article reviews the current understanding of the apoptotic pathways, including the extrinsic (cytoplasmic) and intrinsic (mitochondrial) pathways, and the agents being developed to target these pathways.
1,193 citations
University of Rome Tor Vergata1, Dresden University of Technology2, University of Bari3, Catholic University of the Sacred Heart4, University of Hamburg5, Sapienza University of Rome6, Casa Sollievo della Sofferenza7, University of Freiburg8, University of Cagliari9, University of Modena and Reggio Emilia10, Vita-Salute San Raffaele University11, University of Ulm12, Hannover Medical School13
TL;DR: ATRA plus arsenic trioxide is at least not inferior and may be superior to ATRA plus chemotherapy in the treatment of patients with low-to-intermediate-risk APL.
Abstract: Background All-trans retinoic acid (ATRA) with chemotherapy is the standard of care for acute promyelocytic leukemia (APL), resulting in cure rates exceeding 80%. Pilot studies of treatment with arsenic trioxide with or without ATRA have shown high efficacy and reduced hematologic toxicity. Methods
1,184 citations