Toxicity profile and pharmacokinetic study of a phase I low-dose schedule-dependent radiosensitizing paclitaxel chemoradiation regimen for inoperable non-small-cell lung cancer

PURPOSE: We report the toxicity profile and pharmacokinetic data of a schedule-dependent chemoradiation regimen using pulsed low-dose paclitaxel for radiosensitization in a Phase I study for inoperable non-small-cell lung cancer. METHODS AND MATERIALS: Paclitaxel at escalating doses of 15 mg/m(2), 20 mg/m(2), and 25 mg/m(2) were infused on Monday, Wednesday, and Friday with daily chest radiation in cohorts of 6 patients. Daily radiation was delayed for maximal G2/M arrest and apoptotic effect, an observation from preclinical investigations. Plasma paclitaxel concentration was determined by high-performance liquid chromatography. RESULTS: Dose-limiting toxicities included 3 of 18 patients with Grade 3 pneumonitis and 3 of 18 patients with Grade 3 esophagitis. There was no Grade 4 or 5 pneumonitis or esophagitis. There was also no Grade 3 or 4 neutropenia, thrombocytopenia, anemia or neuropathy. For Dose Levels I (15 mg/m(2)), II (20 mg/m(2)), and III (25 mg/m(2)), the mean peak plasma level was 0.23 +/- 0.06 micromol/l, 0.32 +/- 0.05 micromol/l, and 0.52 +/- 0.14 micromol/l, respectively; AUC was 0.44 +/- 0.09 micromol/l, 0.61 +/- 0.1 micromol/l, and 0.96 +/- 0.23 micromol/l, respectively; and duration of drug concentration >0.05 micromol/l (t > 0.05 micromol/l) was 1.6 +/- 0.3 h, 1.9 +/- 0.2 h, and 3.0 +/- 0.9 h, respectively. CONCLUSION: Pulsed low-dose paclitaxel chemoradiation is associated with low toxicity. Pharmacokinetic data showed that plasma paclitaxel concentration >0.05 micromol/l for a minimum of 1.6 h was sufficient for effective radiosensitization.     

Treatment of acute promyelocytic leukemia with arsenic trioxide: clinical and basic studies

Arsenic trioxide (As2O3) has recently been identified as an effective drug in the treatment of newly diagnosed and relapsed acute promyelocytic leukemia (APL) without cross-resistance to all-trans retinoic acid and achieved complete remission rates of 80-90% according to most reports. With intravenous infusion at a dose of 0.08-0.16 mg/kg daily, a course of 28-42 days is required to induce remission. As2O3 in combination with chemotherapy as postremission therapy results in longer survival than arsenic alone. In vitro, As2O3 exerts dose-dependent dual effect; triggering apoptosis at relatively high concentration (0.5-2.0 micromol/l), which is associated with the disruption of mitochondrial transmembrane potentials, while inducing partial differentiation at low concentration (0.1-0.5 micromol/l), which might be related to retinoic acid signaling pathway. Importantly, at both concentrations, As2O3 can degrade PML (promyelocytic leukemia) -RAR alpha (retinoic acid receptor), an oncoprotein that has a central role in leukemogenesis.     

氧化砷对MR2细胞耐药转运分子作用的研究

目的探讨三氧化二砷(As2O3)对肿瘤耐药转运分子的作用。方法以耐全反式维甲酸(ATRA)早幼粒白血病细胞株MR2为研究对象,以非耐药早幼粒白血病细胞株NB4为对照组,用免疫组化法观察P糖蛋白(Pgp)、多药耐药相关蛋白(MRP)和肺耐药相关蛋白(LRP)的表达。结果MR2细胞Pgp表达为30%～40%,NB4细胞为10%～20%,二者差异有极显著性(P<0.001)。MR2细胞MRP表达为56.9±3.4～21.2±1.1,NB4细胞为20.6±5.3～16.7±1.2,二者差异有极显著性(P<0.001)。0.5～2.0μmol/LAs2O3能显著降低MR2细胞中Pgp和MRP的表达,而对LRP的表达无影响。MR2细胞中Pgp和MRP表达的降低与As2O3作用浓度和作用时间呈负相关。结论MR2细胞耐药转运分子Pgp和MRP表达的下调,可能是As2O3克服耐药的敏感靶分子,而LRP则否。ATRA可能是Pgp和MRP的转运底物     

Arsenic trioxide-induced apoptosis and differentiation are associated respectively with mitochondrial transmembrane potential collapse and retinoic acid signaling pathways in acute promyelocytic leukemia.

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.     

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.     

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。     

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。     

Arsenic trioxide, a therapeutic agent for APL.

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.     

Arsenic trioxide cytotoxicity in steroid and chemotherapy-resistant myeloma cell lines: enhancement of apoptosis by manipulation of cellular redox state.

PURPOSE: We investigated the ability of pretreatment with buthionine sulfoximine (BSO) to overcome a priori resistance to arsenic trioxide (As(2)O(3)) in multiple myeloma (MM) cells and determine whether this was through an apoptotic mechanism that involves changes in the cellular redox state. EXPERIMENTAL DESIGN: Using a panel of dexamethasone and chemotherapy-resistant MM cell lines, we examined growth inhibition, induction of apoptosis, and changes in the redox state by As(2)O(3) alone or after preincubation with BSO. RESULTS: Whereas the sensitive cell lines showed 100% killing at 0.5 micromol/liter of As(2)O(3), the resistant cell lines required BSO pretreatment to achieve 100% killing at this dose. By comparison, the peak As(2)O(3) plasma concentration in acute promyelocytic leukemia in patients successfully treated was 5-7 micromol/liter with rapid decline to a sustained level of 1-2 micromol/liter. We demonstrated that BSO and As(2)O(3)-induced cytotoxicity was attributable to induction of apoptosis accompanied by activation of the death signals: caspases 3, 8, and 9. CONCLUSIONS: We have demonstrated that growth inhibition of highly resistant MM cell lines by As(2)O(3) is facilitated by BSO and that this effect is accompanied by caspase activation, presumably leading to activation of apoptosis. These data indicate that steroid and chemotherapy-resistant MM cell lines can be overcome by manipulation of the cellular redox state. Because BSO and As(2)O(3) can be used at clinically relevant concentrations, we believe that our observations may have important implications for the treatment of MM.     

Arsenic enhances the activation of Stat1 by interferon gamma leading to synergistic expression of IRF-1

Arsenic trioxide (As2O3) can induce clinical remission in patients with acute promyelocytic leukemia (APL), including those who have relapsed after treatment with all-trans-retinoic acid (RA). In vitro studies with the APL-derived NB4 cell line showed that As2O3 exerts a dose-dependent dual effect, which induces apoptosis at 1 microM, whereas at a lower concentration of 0.1 microM, a partial differentiation of APL is observed. In non-APL cells, interferon (IFN) alpha and 1 microM As2O3 act synergistically to induce apoptosis. In this report, we show that in NB4 cells and in two RA-resistant NB4-derived cell lines, NB4-R1 and NB4-R2, IFNalpha or IFNgamma combined with 0.1 microM As2O3 lead to an increased maturation effect. Moreover, IFNgamma alone is able to differentiate RA-sensitive and -resistant cells with a higher maturation effect on NB4-R2 cells. In contrast, all these cells underwent apoptosis in the presence of the cytokine and a higher concentration of As2O3. IFNgamma boosted As2O3-induced apoptosis in APL cells as tested by TUNEL, Annexin V staining and activation of caspase 3. As2O3 differently altered IFN-induced gene products; it downregulated PML/RARalpha and PML, did not alter PKR and Stat1, and upregulated interferon regulatory family (IRF)-1. Synergism by IFNgamma and arsenic on IRF-1 expression is mediated by a composite element in the IRF-1 promoter that includes an IFNgamma-activation site (GAS) overlapped by a nonconsensus site for nuclear factor kappa B (NFkappaB). Arsenic has no effect on NFkappaB, whereas it enhances the activation of Stat1 by IFNgamma in NB4 cells leading to an increase in IRF-1 expression.     

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.     

三氧化二砷联合丁硫氨酸亚砜胺诱导人白血病K562/ADM细胞凋亡

目的 观察三氧化二砷(As2O3)联合丁硫氨酸亚砜胺(BSO)对肿瘤多药耐药细胞K562/ADM的诱导凋亡效应,探讨谷胱甘肽(GSH)的含量变化对As2O3作用效果的影响.方法 以0.5、2.0、5.0 μmol/L As2O3单独及联合100 μmol/L BSO作用于K562/ADM细胞,应用二苯基溴化四氮唑蓝(MTT)比色法检测细胞的增殖活性,Annexin V/PI标记法观察细胞的凋亡效应,分光光度法检测细胞内GSH含量的变化.结果 K562/ADM细胞内GSH含量为(81.13±3.91)mg/g prot,明显高于K562细胞(P＜0.01).BSO单独或联合As2O3作用下,随作用时间的延长,K562/ADM细胞内GSH含量逐渐降低.临床剂量(0.5、2.0 μmol/L)As2O3联合BSO作用下,抑制作用逐步增强,72 h两组的细胞增殖抑制率分别为(90.63±5.95)%和(86.12±6.11)%,均分别高于单用相应剂量As2O3组(P＜0.01);凋亡效应逐步增强,72 h两组的细胞凋亡率分别为(82.15±9.28)%和(92.72±9.41)%,均分别高于单用相应剂量As2O3组(P＜0.01).结论 GSH的含量变化与As2O3的作用效果密切相关,As2O3联合BSO可有效诱导K562/ADM细胞发生凋亡.     

Arsenic derivatives in hematologic malignancies: a role beyond acute promyelocytic leukemia?

The importance of arsenic trioxide (As2O3) has been underscored over the last decade due to its efficacy against acute promyelocytic leukemia (APL), a disease in which this agent has been associated with complete hematologic and molecular remission rates of 87% and 83%, respectively. The different molecular mechanisms of action of As2O3 suggest its applicability in hematologic malignancies other than APL. However, responses obtained thus far have consisted of improvements in signs and symptoms without the elimination of a given disease. Toxicities derived from As2O3 are significant but manageable and reversible. However, the risk/benefit ratio of As2O3 in hematologic malignancies other than APL is still unclear. The development of new generations of orally bioavailable inorganic, as well as new organic, arsenic compounds with improved toxicity profiles may bolster the therapeutic application of arsenic derivatives in hematologic malignancies such as leukemia, multiple myeloma and myelodysplastic syndromes.     

Arsenic compounds as anticancer agents

In this paper the use of arsenic compounds as anticancer agents in clinical trials and in in vitro investigations is reviewed, including the experience at our institute. Treatment of newly diagnosed and relapsed patients with acute promyelocytic leukemia (APL) with arsenic trioxide (As2O3) has been found to result in complete remission (CR) rates of 85-93% when given by intravenous infusion for 2-3 h at a dose of 10 mg/day diluted in 5% glucose saline solution. Patients exhibit a response in 28-42 days. CR rates after administration of Composite Indigo Naturalis tablets containing arsenic sulfide and of pure tetraarsenic tetrasulfide reached 98% and 84.9%, respectively. At higher concentrations (1-2 microM), arsenic induced apoptosis, while at lower concentrations (0.1-0.5 microM), it triggered cell differentiation in vitro. As2O3-induced apoptosis has been observed in many cancer cell lines, including esophageal carcinoma, gastric cancer, neuroblastoma, lymphoid malignancies, and multiple myeloma. Its effectiveness was confirmed in the treatment of multiple myeloma. Arsenic compounds are effective agents in the treatment of APL and their activity against other types of cancer requires further investigation.     

An efficient therapeutic approach to patients with acute promyelocytic leukemia using a combination of arsenic trioxide with low-dose all-trans retinoic acid

The use of arsenic trioxide (As2O3, ATO) combined with all-trans retinoic acid (ATRA) has recently been reported to induce remission in patients with acute promyelocytic leukemia (APL). However, its efficiency remains inconclusive mainly due to the small number of the available cases. In this study, therefore, we present a clinical study using a combination of ATO with low-dose ATRA (LD-ATRA) to treat 108 APL patients (80 newly diagnosed patients, 28 relapsed patients). Therapeutic outcomes using the ATO/LD-ATRA approach were compared with those of APL patients treated either with ATO alone (65 patients) or ATRA alone (51 patients). The results showed that the ATO/LD-ATRA approach provided significantly better therapeutic outcomes as compared to either ATO or ATRA alone, as evidenced by lower mortality, a higher CR rate and a reduced period to CR. In addition, the toxic side-effects have been no worse with the combined ATO/LD-ATRA treatment than with either ATO or ATRO alone and in some cases have been reduced. These data suggest that the ATO/LD-ATRA regimen is superior to either regimen given alone to patients with APL.     

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.     

Arsenic trioxide induces apoptosis in leukemia/lymphoma cell lines via the CD95/CD95L system

Although arsenic trioxide (As2O3) has been shown to be an effective anticancer agent for acute promyelocytic leukemia (APL), its mechanisms of action as well as its effect on other leukemias than APL remain unclear. We studied in vitro effects of As2O3 at low concentrations (1.0-2.0 microM) on two human leukemia/lymphoma cell lines, HL-60, an acute myeloid leukemia cell line, and RL, a B-cell lymphoma cell line. As2O3 inhibited proliferation of HL-60 cells and RL cells to the similar degree to the reported inhibition by an APL cell line, NB4. As2O3-treated cell lines exhibited typical morphologic changes of apoptosis such as nuclear condensation and apoptotic bodies, and a cell cycle arrest at the subG1 phase. As2O3-treated cell lines also showed upregulation of CD95/CD95L expression and activation of caspases 8 and 3. Treatment of these cells with anti-CD95 antibodies capable of blocking the CD95 signaling pathway ameliorated As2O3-induced apoptosis. These data suggest that As2O3 can inhibit growth of leukemia/lymphoma cells by inducing the cell cycle arrest and apoptosis that is partially mediated by the CD95/CD95L system.     

Solid tumors subsequent to arsenic trioxide treatment for acute promyelocytic leukemia

Arsenic trioxide (As(2)O(3)) is highly efficacious for acute promyelocytic leukemia (APL). Environmental arsenic exposure predisposes to malignancies, but the risk for therapeutic arsenic is undefined. Three APL patients (de novo, 2; therapy-related, 1) in a cohort of 59 cases given oral-As(2)O(3) for induction and maintenance treatment developed secondary cancers (nasopharyngeal carcinoma, 2; colonic adenocarcinoma, 1) at 16, 36 and 55 months post-As(2)O(3) therapy. Retrospective analysis of biomarkers (Epstein Barr virus serology and quantification, carcinoembryonic antigen) showed the potential presence of cancers before or shortly after As(2)O(3) therapy, suggesting that As(2)O(3) had not initiated these malignancies. Compared against matched background population, there was an increased risk of second cancer (p=0.012, standard incidence ratio=6.5; 95% confidence interval=1.4-19.0).     

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。