The use of arsenic trioxide (As2O3) in the treatment of acute promyelocytic leukemia

Arsenic trioxide (As2O3) has been shown to be even more effective than all-trans retinoid (ATRA) in the treatment of acute promyelocytic leukemia (APL). The combination of induction of apoptosis, induction of differentiation and inhibiting the proliferation, and killing of APL cells could be the main cellular mechanisms of As2O3 in APL treatment. As2O3 may affect APL cells by disturbing the activities of some important intracorporal enzymes, regulating the related gene expression and arresting the progression of cell cycle.     

Clinical outcomes of therapeutic leukapheresis in acute promyelocytic leukemia: A single-center retrospective cohort study

BackgroundIn acute promyelocytic leukemia (APL), increased cell burden in the peripheral blood due to either the disease itself or early treatment with all-trans retinoic acid could cause hyperleukocytosis (HL) before induction chemotherapy. However, therapeutic leukapheresis has seldom been used because of concerns of subsequent coagulopathy after this invasive procedure. The aim of this study was to evaluate the effects of leukapheresis in APL, especially for efficacy and safety.MethodsWe retrospectively analyzed newly diagnosed patients with APL from January 2009 to March 2022. Among 323 patients, 85 had white blood cell count above 40 × 10⁹/L before induction chemotherapy. Thirty-nine patients were initially treated with leukapheresis, whereas the other 46 were not. Clinical and laboratory parameters between these groups were compared.ResultsThere was a trend toward favorable 30-day survival rate for the leukapheresis group compared with the non-leukapheresis group (76.9% and 67.4%; P = 0.24). The complications including subsequent intensive unit care (P = 0.23), severe hemorrhagic events (P = 0.13) showed no significant differences between the two groups. The patients were divided into subcohorts, and the survival rates of the leukapheresis and non-leukapheresis groups were 92.3% (95% confidence interval [CI], 77.8%–100.0%) versus 58.3% (95% CI, 38.6%–78.1%) (P = 0.03) in “sequential HL” and 76.7% (95% CI, 61.5%–91.8%) versus 54.8% (95% CI, 37.3%–72.4%) (P = 0.03) in “symptomatic HL,” respectively. Moreover, in the “sequential HL” subcohort, the cumulative incidence of differentiation syndrome and following adverse events were significantly lower in the leukapheresis group.ConclusionsIn APL with “sequential HL” or “symptomatic HL” from either the disease itself or the effect of all-trans retinoic acid, therapeutic leukapheresis could be applied to reduce leukemic cell burden without significant risks.     

Insight into the selectivity of arsenic trioxide for acute promyelocytic leukemia cells by characterizing Saccharomyces cerevisiae deletion strains that are sensitive or resistant to the metalloid

The genome-wide set of Saccharomyces cerevisiae deletion strains provides the opportunity to analyze how other organisms may respond to toxic agents. Since arsenic trioxide selectively kills human acute promyelocytic leukemia (APL) cells by a poorly understood mechanism we screened the yeast deletion strains for sensitivity or resistance. In addition to confirming mutants previously identified as sensitive to sodium arsenite, a large number of additional genes, and cellular processes, were required for arsenic trioxide tolerance. Of the 4546 mutants, 7.6% were more sensitive to arsenic trioxide than the wild type, while 1.5% was more resistant. IC50 values for all sensitive and resistant mutants were determined. Prominent as sensitive was that missing the MAP kinase, Hog1. The most resistant lacked the plasma-membrane glycerol and arsenite transporter, Fps1. Hog1 and Fps1 control the response to osmotic stress in yeast by regulating glycerol production and plasma membrane flux, respectively. We therefore tested whether APL cells have impaired osmoregulation. The APL cell line NB4 did not produce glycerol in response to osmotic stress and underwent apoptotic cell death. Moreover, the glycerol content of NB4 and differentiated NB4 cells correlated with the level of arsenic trioxide uptake and the sensitivity of the cells. Additionally, NB4 cells accumulated more arsenic trioxide than non-APL cells and were more sensitive. These findings demonstrate the usefulness of the S. cerevisiae deletion set and show that the selectivity of arsenic trioxide for APL cells relates, at least in part, to impaired osmoregulation and control of uptake of the drug.     

Arsenic trioxide promotes histone H3 phosphoacetylation at the chromatin of CASPASE-10 in acute promyelocytic leukemia cells

Arsenic trioxide (As(2)O(3)) is highly effective for the treatment of acute promyelocytic leukemia, even in patients who are unresponsive to all-trans-retinoic acid therapy. As(2)O(3) is believed to function primarily by promoting apoptosis, but the underlying molecular mechanisms remain largely unknown. In this report, using cDNA arrays, we have examined the changes in gene expression profiles triggered by clinically achievable doses of As(2)O(3) in acute promyelocytic leukemia NB4 cells. CASPASE-10 expression was found to be potently induced by As(2)O(3). Accordingly, caspase-10 activity also substantially increased in response to As(2)O(3) treatment. A selective inhibitor of caspase-10, Z-AEVD-FMK, effectively blocked caspase-3 activation and significantly attenuated As(2)O(3)-triggered apoptosis. Interestingly, the treatment of NB4 cells with As(2)O(3) markedly increased histone H3 phosphorylation at serine 10, an event that is associated with acetylation of the lysine 14 residue. Chromatin immunoprecipitation assays revealed that As(2)O(3) potently enhances histone H3 phosphoacetylation at the CASPASE-10 locus. These results suggest that the effect of As(2)O(3) on histone H3 phosphoacetylation at the CASPASE-10 gene may play an important role in the induction of apoptosis and thus contribute to its therapeutic effects on acute promyelocytic leukemia.     

Advances in the understanding and management of acute promyelocytic leukemia

Considerable progress has been made over the past decade in the understanding and management of acute promyelocytic leukemia (APL). At the laboratory level, molecular mechanisms underlying the arrest of differentiation that typically features in this malignancy, have been clarified and currently provide important models for addressing future investigation aimed at releasing the maturation block in other malignancies. In the clinic, advances in the management of APL have converted this rapidly fatal disease into the most frequently curable leukemia in adults. Use of retinoids in combinatorial protocols with anthracycline-based chemotherapy for front line treatment currently results in long-term survival and potential cure in at least 60% of newly diagnosed patients. Even after relapse, the disease is still curable in a high percentage of cases by various approaches including combinations of chemotherapy, retinoids, arsenic trioxide, stem cell transplantation and antibody-targeted chemotherapy. Genetic testing for identification of the disease-specific gene rearrangement and monitoring of residual disease have proved critical in establishing correct diagnosis and better evaluate the response to therapy at the molecular level. Current 'hot' issues for clinical investigation include: (i) better understanding and management of the severe coagulopathy present at diagnosis in most patients; (ii) the definition of risk categories to improve identification of patients at highest risk of relapse and (iii) the translation of successful differentiation therapy to other leukemia subsets.     

The cell biology of disease: Acute promyelocytic leukemia, arsenic, and PML bodies

Acute promyelocytic leukemia (APL) is driven by a chromosomal translocation whose product, the PML/retinoic acid (RA) receptor α (RARA) fusion protein, affects both nuclear receptor signaling and PML body assembly. Dissection of APL pathogenesis has led to the rediscovery of PML bodies and revealed their role in cell senescence, disease pathogenesis, and responsiveness to treatment. APL is remarkable because of the fortuitous identification of two clinically effective therapies, RA and arsenic, both of which degrade PML/RARA oncoprotein and, together, cure APL. Analysis of arsenic-induced PML or PML/RARA degradation has implicated oxidative stress in the biogenesis of nuclear bodies and SUMO in their degradation.     

Myeloid sarcoma of the tongue as a first manifestation of acute promyelocytic leukemia: A case report

IntroductionWe describe a 35-year-old male patient showing a myeloid sarcoma (MS) of the tongue as the first manifestation of acute promyelocytic leukemia (APL). The MS can appear in all parts of the human body, but it is extremely rare in the tongue.Clinical caseThe main symptoms were a pain in the tongue, asthenia, gingivorrhagia, fever. We found a tumor in the tongue, which was irregular in size and located in the posterior region of the right lateral edge of the tongue. The diagnosis of MS was made by the anatomopathological and immunohistochemical study, while the definite diagnosis of APL was confirmed by the molecular test. The treatment of APL was based on the administration of trans-retinoic acid 45 mg/m² daily continuously and daunorubicin 60 mg/m² every other day for 4 doses, with a favorable therapeutic response to APL and MS.ConclusionPromyelocytic myeloid cells can infiltrate many organs extramedullary, such as the tongue, and this might precede bone marrow infiltration. The early identification of myeloid sarcoma allows to carry out an early treatment of the APL.     

Characterization of arsenic trioxide resistant clones derived from Jurkat leukemia T cell line: Focus on PI3K/Akt signaling pathway

In this study the role of PI3K/Akt signaling pathway in arsenic trioxide (ATO)-treated parental Jurkat cells and also in derived ATO-resistant clones grown in the presence of given ATO concentration was investigated. ATO-resistant clones (cultured for 8–12 weeks in the presence of 1, 2.5 and 5 μM ATO) were characterized by high viability in the presence of ATO but slower growth rate compared to the parental cells. Morphological and functional characterization of derived ATO-resistant clones revealed that they did not differ fundamentally from parental Jurkat cells in terms of cell size, level of GSH, the lysosomal fluorescence or CD95/Fas surface antigen expression. However, a slight increase in the mitochondrial potential (JC-1 staining) was detected in the clones compared to parental Jurkat cells. Side population analysis (Vybrant DyeCycle Violet™ staining) in ATO resistant clones did not indicate any enrichment withcancer stem cells. Akt1/2, AktV or wortmannin inhibitors decreased viability of ATO-resistant clones grown in the presence of ATO, with no effect on ATO-treated parental cells. Flow cytometry analysis showed that ATO decreased the level of p-Akt in ATO-treated parental cells, while the resistant clones exhibited higher levels of p-Akt immunostaining than parental Jurkat cells. Expression analysis of 84 genes involved in the PI3K/Akt pathway revealed that this pathway was predominantly active in ATO-resistant clones. c-JUN seems to play a key role in the induction of cell death in ATO-treated parental Jurkat cells, as dose-dependent strong up-regulation of JUN was specific for the ATO-treated parental Jurkat cells. On the other hand, changes in expression of cyclin D1 (CCND1), insulin receptor substrate 1 (IRS1) and protein kinase C isoforms (PRKCZ,PRKCB and PRKCA) may be responsible for the induction of resistance to ATO. The changes in expression of growth factor receptor-bound protein 10 (GRB10) observed in ATO-resistant clones suggest a possibility of induction of different mechanisms in development of resistance to ATO depending on the drug concentration and thus involvement of different signaling mediators.     

Synthesis of 4(3H)quinazolinimines with selective cytotoxic effect on human acute promyelocytic leukemia cells

We synthesized a new family of six 4(3H)quinazolinimines based on the reaction between (E)-N-(2-cyanophenyl)benzimidoyl chloride and substituted anilines reaching the formation of their corresponding C2, N3-substituted quinazoliniminium chlorides. This method provides novel, direct and flexible access to diverse substituted 4(3H)quinazolinimines.New compounds obtained following the proposed synthesis were fully characterized and, including the thirteen 4(3H)quinazolinimines synthesized by this method and previously reported by us, were used to study its cytotoxic effect on neoplastic cell lines. The mechanism involved in cell toxicity was also studied. Results showed that these compounds were highly cytotoxic, in particular on Human Promyelocytic Leukemia cells (HL60) and Chronic Myelogenous Leukemia cells (K562) when compared with conventional antineoplastic drugs such as etoposide and cisplatin. The mechanism associated to cytotoxic effect was mainly apoptosis, which not was decreased by antioxidant addition, thereby suggesting that the compounds exert apoptotic death through a mechanism unrelated with oxidative stress.     

急性早幼粒细胞白血病患者小孢根霉变种感染1例

报道1例由小孢根霉变种导致的皮肤毛霉病.患者女,30岁.因患急性早幼粒细胞白血病,化疗后继发口腔颌面部小孢根霉变种感染,表现为发热、右侧颊黏膜水肿,皮损中央溃疡、焦痂,周边组织炎性水肿,以面颊部、颌下区为中心明显肿胀,逐渐累及右侧颈部及右下颌,进行性加重.坏死组织涂片镜检显示有粗大、无分隔直角菌丝,真菌学检查鉴定为小孢根霉,分子测序证实为小孢根霉变种.给予两性霉素B、伊曲康唑静脉滴注和手术清创,坏死组织连续3次真菌培养均未培养出小孢根霉变种,患者体温逐渐恢复正常,治疗2周后颔面部肿胀明显减退,浅表淋巴结未触及肿大,4周后额部及右眼睑肿胀已完全消退,伤口结痂愈合.随访2 a,右侧颌下可见长约2 cm手术疤痕,未见皮肤毛霉病复发.     

Targeted therapy: The new lease on life for acute promyelocytic leukemia, and beyond

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.     

三氧化二砷对人胃腺癌细胞株SGC-7901细胞核及线粒体作用的实验研究

目的:研究三氧化二砷(As203)对人胃腺癌细胞株SGC-7901的生物效应及其对线粒体和半胱氨酸蛋白酶家族-3(caspase-3)的作用.方法:通过MTT比色实验检测不同浓度As2O3对该细胞株的生长抑制作用;经Hoechst 33258染色后用荧光显微镜观察细胞核的形态变化;经过细胞线粒体膜电位检测区分凋亡细胞与正常细胞,并经流式细胞仪分析;caspase-3吸光度检测法测定As2O3组caspase-3的活化程度.结果:As2O3明显抑制SGC-7901人胃腺癌细胞的生长,抑制作用的强度呈时间依赖性(方差分析,P<0.01);Hoechst 33258染色后荧光显微镜观察细胞核固缩碎裂边集呈强蓝色荧光;线粒体膜电位检测法,流式细胞仪检测法,caspase-3吸光度检测法均检测到胃腺癌细胞的凋亡.结论:As2O3破坏线粒体跨膜电位和激活caspase-3活性可能是As2O3诱导人胃腺癌SGC-7901细胞凋亡的重要机制.     

RXR, a key member of the oncogenic complex in acute promyelocytic leukemia

Acute promyelocytic leukaemia (APL) is induced by fusion proteins always implying the retinoic acid receptor RARa. Although PML-RARa and other fusion oncoproteins are able to bind DNA as homodimers, in vivo they are always found in association with the nuclear receptor RXRa (Retinoid X Receptor). Thus, RXRa is an essential cofactor of the fusion protein for the transformation. Actually, RXRa contributes to several aspects of in vivo -transformation: RARa fusion:RXRa hetero-oligomeric complexes bind DNA with a much greater affinity than RARa fusion homodimers. Besides, PML-RARa:RXRa recognizes an enlarged repertoire of DNA binding sites. Thus the association between fusion proteins and RXRa regulates more genes than the homodimer alone. Titration of RXRa by the fusion protein may also play a role in the transformation process, as well as post-translational modifications of RXRa in the complex. Finally, RXRa is required for rexinoid-induced APL differentiation. Thus, RXRa is a key member of the oncogenic complex.     

FLT3 and NPM-1 mutations in a cohort of acute promyelocytic leukemia patients from India

Background:

Acute promyelocytic leukemia (APL) with t (15;17) is a distinct category of acute myeloid leukemia (AML) and is reported to show better response to anthracyclin based chemotherapy. A favorable overall prognosis over other subtypes of AML has been reported for APL patients but still about 15% patients relapse.

Methods:

This study evaluated the presence of Famus like tyrosine kinase-3 (FLT3) and nucleophosmin-1 (NPM1) gene mutations in a cohort of 40 APL patients. Bone marrow/peripheral blood samples from patients at the time of diagnosis and follow-up were processed for immunophenotyping, cytogenetic markers and isolation of DNA and RNA. Samples were screened for the presence of mutations in FLT3 and NPM1 genes using polymerase chain reaction followed by sequencing.

Results:

Frequency of FLT3/internal tandem duplication and FLT3/tyrosine kinase domain was found to be 25% and 7% respectively. We observed a high frequency of NPM1 mutation (45%) in the present population of APL patients.