自噬在急性早幼粒细胞白血病中的研究进展

急性早幼粒细胞白血病（APL）具有特征性的t（15;17）（q22;q21）染色体易位,其表达PML-RARα融合蛋白。全反式维甲酸（ATRA）和三氧化二砷（As2O3）诱导早幼粒白血病细胞分化或凋亡,使APL成为第一种可以治愈的白血病。自噬是维持细胞稳态的重要代谢方式之一,最近有研究显示自噬在ATRA／As2O3诱导治疗中发挥重要作用,而且还可能影响APL对药物诱导凋亡作用的敏感性。因此,今后靶向自噬、调控自噬可能成为APL乃至于其他白血病治疗的一种新手段。对近年来自噬对APL的作用研究进行综述。     

Retinoic acid syndrome induced by arsenic trioxide in treating recurrent all-trans retinoic acid resistant acute promyelocytic leukemia

Arsenic Trioxide (As2O3) is an effective agent for treating acute promyelocytic leukemia achieving a complete remission rate of about 60% to 90%. It is similar to all-trans retinoic acid (ATRA) when treating acute promyelocytic leukemia (APL), because both agents have limited side effects compared to conventional chemotherapy, although the treatment period is more prolonged. During treatment, both agents may induce leukocytosis, and in patients taking ATRA, leukocytosis appears to be related to the development of retinoic acid syndrome (RAS). We report here a case of APL treated with ATRA in combination with chemotherapy 3 years earlier. During treatment, an episode of RAS with fever, edema, pericardiac effusion etc. was encountered. Recently, she had a relapse of leukemia, and As2O3 therapy was used. Leukocytosis developed again, and symptoms of fever, skin rash, edema resembling a RAS also developed, which was quickly relieved by steroid administration in a manner resembling response to RAS.     

急性早幼粒细胞白血病耐药机制的研究进展

全反式维甲酸(ATRA)与三氧化二砷(As2O3)作为一线药物治疗急性早幼粒细胞白血病(APL)以来,APL患者的治愈率得到显著提高.但ATRA和(或)As2O3耐药的出现成为一个严重问题.现就近年来新提出的一些耐药机制如融合基因突变、细胞信号通路异常、染色质重构复合物异常、凋亡调控异常、骨髓微环境介导耐药等方面进行综述.     

Extramedullary relapse in a patient with acute promyelocytic leukemia: successful treatment with arsenic trioxide, all-trans retinoic acid and gemtuzumab ozogamicin therapies

Acute promyelocytic leukemia (APL) is characterized by the presence of the t(15;17) translocation, resulting in the PML-RAR fusion protein. Standard treatment consists of the combination of all-trans retinoic acid (ATRA) with an anthracycline that results in complete remission (CR) rates in excess of 90%. Recently, several new agents have been shown to have clinical activity in APL. These include a liposomal formulation of ATRA (lipo-ATRA), and gemtuzumab ozogamicin (GO). Herein, we report a patient with APL who relapsed with extramedullary disease 2.5 years after lipo-ATRA therapy and was successfully treated with the sequence of A2O3, ATRA, and GO and we summarize our experience with patients with isolated extramedullary relapse in APL.     

全反式维甲酸联合三氧化二砷治疗儿童急性早幼粒细胞白血病疗效观察

 目的　观察全反式维甲酸（ ATRA ）联合三氧化二砷（ As2O3）治疗儿童初发急性早幼粒细胞白血病（ APL）的疗效和不良反应。方法　ATRA 联合As2O3治疗初发 APL患儿16例。治疗方案：ATRA 25 mg·m-2·d-1，分2～3次口服，As2O3 0.16 mg·kg-1·d-1，加入生理盐水或50 g／L葡萄糖溶液静脉滴注，持续 4～6 h，1次／d。结果　14 例患者获得完全缓解（CR），CR率87.5 ％，CR时间短，没有明显不良反应。结论　ATRA联合As2O3治疗儿童APL能获得很好疗效。     

全反式维A酸+三氧化二砷联合诱导分化治疗急性早幼粒细胞白血病

 目的 研究联合应用全反式维A酸（ATRA）+三氧化二砷（As2O3）诱导分化治疗急性早幼粒细胞白血病（APL）的疗效及毒副作用。方法 治疗组共46例患者,均给予ATRA+As2O3诱导分化治疗,对照组30例给予ATRA诱导分化治疗,分别判别疗效及毒副作用。结果 治疗组及对照组获得CR时间分别为（26.2±4.0）d,（49.5±8.5）d,差异有统计学意义（P＜0.05）,而两组毒副作用发生率差异无统计学意义（P＞0.05）。结论 联合应用ATRA+ As2O3诱导分化治疗APL获得CR时间明显缩短,而且毒副作用无明显增加。     

低剂量氧化砷治疗早幼粒细胞白血病的实验研究

背景与目的：低剂量三氧化二砷（arsenic trioxide,As2O3）是治疗急性早幼粒细胞性白血病（APL）的有效手段之一,它不仅对初发APL病人有效,而且对全反式维甲酸（ATRA）巳耐受的复发APL病人可获得完全缓解。然而,目前其诱导APL缓解的机制尚不清楚。为此,本研究试图探低剂量As2O3治疗APL的可能机制。方法：以APL细胞株NB4和来源于APL患者骨髓的原代细胞为模型。通过观察细胞形态、对四氮唑蓝的还原能力和细胞表面分化抗原的变化来鉴定细胞分化;并应用免疫荧光和Western blot分析细胞内PML-RARα融合蛋白的变化。结果：0.25μmol/L AS2O3联合环腺苷酸（cAMP）拟似物8-对氯苯硫基环腺苷酸（8-CPT-CAMP）可诱导NB4细胞和原代细胞分化,而且该效应能被蛋白激酶PKA的抑制剂H89抑制。进一步研究还显示8-CPT-CAMP可以促进AS2O3介导的PML-RARα融合蛋白降解。结论：cAMP可增强AS2O3对APL细胞的分化诱导效应。     

Arsenic trioxide therapy for relapsed acute promyelocytic leukemia: an useful salvage therapy

Arsenic trioxide (As2O3) was recently identified as a very potent agent against acute promyelocytic leukemia (APL). Intravenous infusion of 10 mg As2O3 daily for one to two months can induce significant complete remission (CR) of APL, and there is no cross drug-resistance between As2O3 and other antileukemic agents, including all-trans retinoic acid (ATRA). The CR rate of relapsed and/or refractory APL patients who received As2O3 treatment ranged from 52.3% to 93.3%. The median duration to CR ranged from 38 to 51 days, with accumulative As2O3 dosage of 340-430 mg. Although most adverse reactions of As2O3 treatment were tolerable, certain infrequent but severe toxicities related to As2O3 were observed, including renal failure, hepatic damage, cardiac arrhythmia and chronic neuromuscular degeneration, which should be monitored carefully. As2O3 can induce partial differentiation and subsequent apoptosis of APL cells through degradation of wild type PML and PML/RAR alpha chimeric proteins and possible anti-mitochondrial effects. Like the treatment of ATRA in APL, early relapses from As2O3 treatment within a few months were not infrequently seen, indicating that rapid emerging resistance to As2O3 can occur. Nevertheless, the PML/RAR alpha fusion protein was reported to disappear in some APL patients who received As2O3, and who might earn long-survival. However, the follow-up is still too short to draw the conclusion. Intriguingly, it has been shown that As2O3 can also induce apoptosis of other non-APL tumor cells with clinical achievable concentrations. However, the detailed molecular mechanisms are not yet fully understood. Further studies regarding to the pharmacological characters, clinical efficacies, toxicities, apoptogenic mechanisms, and spectrum of anti-tumor activity of As2O3 are warranted.     

Advances in therapies for acute promyelocytic leukemia

Acute promyelocytic leukemia (APL), a distinct subtype of acute myelogenous leukemia (AML), results from the arrest of the maturation of hematopoietic progenitors at the promyelocyte stage. It has been shown that APL is associated with a reciprocal chromosomal translocation, involving chromosomes 15 and 17, which fuses the gene encoding the retinoic acid receptor α (RARα) and the promyelocytic leukemia (PML) gene. The resultant PML-RARα fusion protein plays a critical role in the pathogenesis of APL. Although there are many subtypes of AML, all are typically managed using a standard chemotherapy regimen of an anthracycline plus cytarabine arabinoside (CA). Despite high rates of complete remission following standard chemotherapy, most patients relapse and long-term disease-free survival is only 30-40%. The introduction of drugs such as all-trans retinoic acid (ATRA) that promote progenitor differentiation by directly inhibiting the PML-RARα fusion protein has changed the treatment paradigm for APL and markedly improved patient survival. The purposes of the present review are to provide the latest results and future directions of clinical research into APL and to illustrate how new therapies, such as ATRA plus anthracycline-based induction and consolidation therapy, risk-adapted therapy, salvage therapy containing arsenic trioxide-based regimens, and hematopoietic stem cell transplantation, have improved the treatment outcomes for APL patients.     

Acute promyelocytic leukemia in childhood

Acute promyelocytic leukemia (APL) is a relatively rare form of acute myelogenous leukemia (AML). In the United States, APL in children constitutes only 5% to 10% of AML. Molecularly, the disease is characterized by a fusion protein, promyelocytic leukemia (PML)-retinoic acid receptor (RAR)-α that results from a balanced reciprocal translocation between the PML gene on chromosome 15 and the RAR-α (RARA) gene on chromosome 17. A major advance in the field of APL treatment has been the use of all-trans-retinoic acid (ATRA). Advances in the treatment of APL have taken this form of AML from a disease with significant morbidity and mortality to one with an excellent outcome. This has resulted largely from the incorporation of ATRA into frontline regimens with chemotherapy. Anthracyclines remain a cornerstone of treatment at this point. Recent trials have shown a role for arsenic trioxide in both newly diagnosed and relapsed APL.     

Retinoid/arsenic combination therapy of promyelocytic leukemia: induction of telomerase-dependent cell death.

Acute promyelocytic leukemia (APL) is efficiently treated with a cell differentiation inducer, all-trans retinoic acid (ATRA). However, a significant percentage of patients still develop resistance to this treatment. Recently, arsenic trioxide (As2O3), alone or in combination with ATRA, has been identified as an alternative therapy in patients with both ATRA-sensitive and ATRA-resistant APL. Previous investigations restricted the mechanism of this synergism to the modulation and/or degradation of PML-RARalpha oncoprotein through distinct pathways. In this study, using several ATRA maturation-resistant APL cell lines, we demonstrate in vitro that the success of ATRA/As2O3 treatment in APL pathology can be explained, at least in part, by a synergistic effect of these two drugs in triggering downregulation of telomerase efficient enough to cause telomere shortening and subsequent cell death. Such long-term low-dose combinatorial therapy strategies, developed also to avoid acute side effects, reinforce the notion that the antitelomerase strategy, based on a combination of active agents, should now be considered and evaluated not only in APL but also in other malignancies.     

Tissue factors on acute promyelocytic leukemia and endothelial cells are differently regulated by retinoic acid, arsenic trioxide and chemotherapeutic agents.

The aberrant expression of tissue factor (TF) in acute promyelocytic leukemia (APL) cells has been implicated in the pathogenesis of the APL coagulopathy. In this study, we found that in APL patients receiving ATRA or As2O3 treatment, the improvement in hypercoagulobility and hyperfibrinolysis paralleled the correction of plasma fibrinogen level and amelioration of bleeding symptoms. Notably, clinical improvement was also correlated to ATRA/As2O3-induced rapid decrease of membrane procoagulant activity (PCA) and TF contents of APL blasts. Consistent with the in vivo findings, the membrane PCA, TF antigen and its mRNA level within NB4 cells were rapidly down-regulated by 1 microM ATRA or As2O3, while 0.2 microg/ml DNR increased these TF parameters prior to its effect upon apoptosis induction. The down-regulation of TF mRNA by ATRA was partially de novo protein synthesis-dependent and at least partially attributed to a mechanism of destabilizing TF mRNA. On the other hand, in addition to its modulation on mRNA, As2O3 could also induce an accelerated TF protein turnover. These distinct effects were corroborated with the properties of these agents in causing the degradation of PML-RARalpha protein. All three therapeutic agents, however, enhanced the potential of NB4 cells to stimulate the expression of TF and PCA in endothelium. Taken together, our data suggest that the rapid and distinct regulation of TF on APL cells by these therapeutic agents might at least partially contribute to their effects on APL coagulopathy.     

早幼粒白血病-维甲酸受体α融合蛋白对RIAM基因转录的负调控作用探讨

目的:研究异常转录因子早幼粒白血病-维甲酸受体α(promyelocytic leukemia-retinoic acid receptor alpha,PML-RARα)融合蛋白对RIAM基因的转录调控机制.方法:利用表达谱数据库(GSE1159)比较RIAM基因在急性髓系白血病(acute myeloid leukemia,AML)各亚型中的表达情况,以及RIAM基因和PML-RARα融合蛋白之间的相关性.采用蛋白质印迹法和实时荧光定量-PCR法分别检测PML-RARα融合蛋白和RIAM基因在急性早幼粒细胞白血病(acute promyelocytic leukemia,APL)模式细胞株PR9及APL患者来源的细胞株NB4中的表达情况,以及在全反式维甲酸(all-trans retinoic acid,ATRA)处理前后的RIAM mRNA的表达情况.利用染色质免疫沉淀技术检测细胞内PML-RARα融合蛋白在RIAM基因启动子附近的结合情况.结果:RIAM基因在APL(即M3型AML)中的表达水平明显低于其他AML亚型(M0、M1、M2、M4、M5和M7型)和正常造血细胞(P＜0.05).随着PML-RARα融合蛋白的表达,RIAM基因的表达水平明显降低.ATRA能激活RIAM基因的表达,且PML-RARα融合蛋白的表达能增强ATRA对RIAM基因表达的激活效应.PML-RARα融合蛋白结合在RIAM基因的启动子区域.结论:RIAM基因是PML-RARα融合蛋白的靶基因,PML-RARα融合蛋白通过结合到RIAM基因的启动子区域对其转录进行负调控.     

Successful treatment of all-trans retinoic acid resistant and chemotherapy naïve acute promyelocytic patients with arsenic trioxide--two case reports

Arsenic trioxide(As2O3) has proved highly effective in treating both refractory or primary cases of acute promyelocytic leukemia (APL). The role of arsenic trioxide in APL treatment has been confirmed by study groups in China and in the USA. However, what is the role of As2O3 in treating APL? Should it be used as first line therapy, or should it be used as a second line drug. This still remains to be defined. Here, we report two cases of APL, who were treated successfully with As2O3 when they relapsed. Initially, both received all-trans retinoic acid (ATRA) for primary remission induction therapy, and obtained a complete remission. For ethical or personal reasons, they did not receive chemotherapy as consolidation therapy and when they relapsed at 23 months and 12 months later respectively, they both received As2O3 therapy after being resistant to ATRA treatment. Two courses of As2O3 were given and both reached complete remission. There were very few adverse reactions to the drug, only mild abdominal cramps, mild fluid retention, and transient elevation of transaminases. They both had rather good quality of life throughout the treatment and both remain in remission for 32 months and 10 months since therapy, respectively.     

不同方案治疗急性早幼粒细胞白血病169例疗效分析

 目的 探讨不同治疗方案对急性早幼粒细胞白血病（APL）的治疗效果。方法 对不同治疗方案的APL疗效进行回础性分析比较。结果 采用全反式维A酸（ATRA）+三氧化二砷（As2O3）或者两者交替组获得CR中位时间分别为34,35.5 d,与单用ATRA的62 d比较,差异有统计学意义（P＜0.05）。ATRA+As2O3组或两者交替组,3年无病生存率分别为78 %和80 %,与单用ATRA组比较,差异有统计学意义（P＜0.05）。15例行造血干细胞移植（HSCT）者,仅2例复发,其余13例中位无病生存时间（DFS）为11.5年, 该13例PCR检测PML-RARα融合基因转阴性。结论 应用ATRA+As2O3或两者交替加化疗治疗APL获得CR时间明显缩短,而且3年无病生存率相对较高。缓解后6个月进行HSCT者,DFS可进一步延长。     

三氧化二砷(As_2O_3)治疗2例儿童难治性急性早幼粒细胞白血病

为探讨三氧化二砷治疗儿童白血病的效果。对2例难治性儿童患者进行了治疗。1例达CR。使用过程无明显毒副反应，且与全反式维甲酸（ATRA）无交叉耐药。细胞形态学检查显示：AS2O3有诱导分化及促凋亡双重作用。     

Use of arsenic trioxide (As2O3) in the treatment of patients with acute promyelocytic leukemia: the M. D. Anderson experience

BACKGROUND: Approximately 20-30% of patients with acute promyelocytic leukemia (APL) who are treated with all-trans retinoic acid (ATRA) and an anthracycline develop recurrent disease. It has been reported that arsenic trioxide (As(2)O(3)) is effective in this setting. The authors report the experience of The M. D. Anderson Cancer Center with As(2)O(3) in the treatment of patients with recurrent APL. METHODS: Twelve patients who developed recurrent APL after treatment with ATRA were included. Patients received intravenous As(2)O(3) 0.15 mg/kg per day until they achieved a complete remission (CR) or up to a maximum of 60 days. Their median age was 44 years (range, 26-72 years), and the median duration of first remission was 52 weeks (range, 23-292 weeks). RESULTS: All 12 patients achieved a CR. The median time to achieve CR was 52 days (range, 27-75 days). Seven of 10 evaluable patients achieved a molecular remission (i.e., polymerase chain reaction [PCR] analysis was negative for the gene encoding fusion of the nuclear receptor for retinoic acid to the PML gene at the time of CR; 70% of patients; 95% confidence interval, 0.35-0.93), and all other patients had negative PCR results after they received post-remission therapy. All patients received subsequent therapy: Four patients received As(2)O(3) alone, six patients received As(2)O(3) with other chemotherapeutic agents, and two patients received idarubicin plus ATRA without As(2)O(3). Eight patients continued in CR after a median follow-up of 24 months (range, 9-45 months). Side effects were mild, except for two patients who developed Grade 2 and 3 peripheral neuropathy, respectively; one of those patients required discontinuation of therapy. CONCLUSIONS: As(2)O(3) is effective and well tolerated therapy for patients with recurrent APL. Molecular remission may be achieved at the time of CR in the majority of patients, and remissions are durable.