Danusertib,an aurora kinase inhibitor

Introduction: Drugs that interfere with the normal progression of mitosis belong to the most successful cytotoxic agents currently used for anticancer treatment. Aurora kinases are serine/threonine kinases that function as key regulators of mitosis and are frequently overexpressed in human cancers. The use of several small molecule aurora kinase inhibitors as potential anticancer therapeutic is being investigated. Danusertib (formerly PHA-739358) is a small ATP competitive molecule that inhibits aurora A, B and C kinases. Interestingly, danusertib also inhibits several receptor tyrosine kinases such as Abl, Ret, FGFR-1 and TrkA. These tyrosine kinases are involved in the pathogenesis of a variety of malignancies and the observed multi-target inhibition may increase the antitumor activity resulting in extending the indication. Danusertib was one of the first aurora kinase inhibitors to enter the clinic and has been studied in Phase I and II trials.

Areas covered: This review provides an updated summary of preclinical and clinical experience with danusertib up to July 2011.

Expert opinion: Future studies with danusertib should focus on the possibility of combining this agent with other targeted anticancer agents, chemotherapy or radiotherapy. As a single agent, danusertib may show more promise in the treatment of leukemias than in solid tumors.     

Natural anthraquinone compound emodin as a novel inhibitor of aurora A kinase: A pilot study

Aurora kinase A (AURKA) carries out an essential role in proliferation and involves in cisplatin resistance in various cancer cells. Overexpression of AURKA is associated with the poor prognosis of cancer patients. Thus, AURKA has been considered as a target for cancer therapy. Developing AURKA inhibitors became an important issue in cancer therapy. A natural compound emodin mainly extracted from rhubarbs possesses anti-cancer properties. However, the effect of emodin on AURKA has never been investigated. In the present study, molecular docking analysis indicated that emodin interacts with AURKA protein active site. We also found nine emodin analogues from Key Organic database by using ChemBioFinder software. Among that, one analogue 8L-902 showed a similar anti-cancer effect as emodin. The bindings of emodin and 8L-902 on AURKA protein were confirmed by cellular thermal shift assay. Furthermore, emodin inhibited the AURKA kinase activity in vitro and enhanced the cisplatin-DNA adduct level in a resistant ovarian cancer cell line. It seems that emodin may have the potential to inhibit cancer cell growth and enhance cisplatin therapy in cancer with resistance. Collectively, our finding reveals a novel AURKA inhibitor, emodin, which may be vulnerable to ovarian cancer therapy in the future.     

An update on the pharmacokinetics and pharmacodynamics of alisertib,a selective Aurora kinase A inhibitor

Human Aurora kinases, including Aurora kinase A (AURKA), B (AURKB), and C (AURKC), play an essential role in mitotic events such as monitoring of the mitotic checkpoint, creation of bipolar mitotic spindle and alignment of centrosomes on it, also regulating centrosome separation, bio‐orientation of chromosomes and cytokinesis. AURKA and AURKB are key regulators of mitosis and centrosome via polymerizing microfilaments and controlling chromatid segregation. In particular, AURKA plays critical roles in the regulation of mitotic entry, centrosome function, bipolar spindle assembly, and chromosome segregation. AURKA has been found to be overexpressed in various solid and haematological cancers and has been linked with poor prognosis. Its important role in cancer initiation, growth, and metastasis has brought the focus to search for potent and selective AURKA inhibitors for cancer treatment. MLN8237, also known as alisertib, is one selective AURKA inhibitor that has shown remarkable anticancer effects in preclinical studies. Alisertib exhibits favourable pharmacokinetic properties. Alisertib has generally showed good partial response rates of 4–52% and good safety profiles in Phase I and II trials when it is solely administered as well as combined with cytotoxic chemotherapeutic drugs. Recently, the multicentre, randomized Phase III study of alisertib in patients with relapsed or refractory peripheral T‐cell lymphoma has been discontinued due to unsatisfactory efficacy. The low risk of side effects, accessibility, and effectiveness of alisertib makes it a new promising anticancer therapy and further mechanistic and clinical studies are warranted.     

In vitro and in vivo pharmacokinetic characterizations of AMG 900, an orally bioavailable small molecule inhibitor of aurora kinases

1. AMG 900 is a small molecule being developed as an orally administered, highly potent, and selective pan-aurora kinase inhibitor. The aim of the investigations was to characterize in vitro and in vivo pharmacokinetic (PK) properties of AMG 900 in preclinical species.

2. AMG 900 was rapidly metabolized in liver microsomes and highly bound to plasma proteins in the species tested. It was a weak Pgp substrate with good passive permeability.

3. AMG 900 exhibited a low-to-moderate clearance and a small volume of distribution. Its terminal elimination half-life ranged from 0.6 to 2.4?h. AMG 900 was well-absorbed in fasted animals with an oral bioavailability of 31% to 107%. Food intake had an effect on rate (rats) or extent (dogs) of AMG 900 oral absorption.

4. The clearance and volume of distribution at steady state in humans were predicted to be 27.3?mL/h/kg and 93.9?mL/kg, respectively.

5. AMG 900 exhibited acceptable PK properties in preclinical species and was predicted to have low clearance in humans. AMG 900 is currently in Phase I clinical testing as a treatment for solid tumours. Preliminary human PK results appear to be consistent with the predictions.

     

Identification of AKN-032, a novel 2-aminopyrazine tyrosine kinase inhibitor, with significant preclinical activity in acute myeloid leukemia

Aberrant signal transduction by mutant or overexpressed protein kinases has emerged as a promising target for treatment of acute myeloid leukemia (AML). We here present a novel low molecular weight kinase inhibitor, AKN-032, targeting the FMS-like tyrosine kinase 3 (FLT3) and discovered in a new type of screening funnel combining the target therapy approach with sequential cellular screens. AKN-032 was identified among 150 selected hits from three different high throughput kinase screens. Further characterization showed inhibitory activity on FLT3 enzyme with an IC₅₀ of 70 nM. Western blot analysis revealed reduced autophosphorylation of the FLT3-receptor in AML cell line MV4-11 cells after exposure to AKN-032. Flow cytometry disclosed cytotoxic activity against MV4-11, but not against non-malignant 3T3-L1 fibroblast cells. Using a fluorometric microculture cytotoxicity assay, AKN-032 was tested against 15 cell lines and displayed a potent cytotoxic activity in AML cell lines MV4-11 (IC₅₀ = 0.4 μM) and Kasumi-1 (IC₅₀ = 2.3 μM). AKN-032 was also highly cytotoxic in tumor cells from AML patients in vitro. Furthermore, AKN-032 demonstrated significant antileukemic effect in a relatively resistant in vivo hollow fiber mouse model. No major toxicity was observed in the animals. In conclusion, AKN-032 is a promising new kinase inhibitor with significant in vivo and in vitro activity in AML. Results from the hollow fiber mouse assay suggest a favorable toxicity profile. Future studies will focus on pharmacokinetic properties, toxicity as well as further clarifying the mechanisms of action of AKN-032 in AML.     

Investigational FMS-like tyrosine kinase 3 inhibitors in treatment of acute myeloid leukemia

Introduction: Outcomes for the majority of patients with acute myeloid leukemia (AML) remain poor. Over the past decade, significant progress has been made in the understanding of the cytogenetic and molecular determinants of AML pathogenesis. One such advance is the identification of recurring mutations in the FMS-like tyrosine kinase 3 gene (FLT3). Currently, this marker, which appears in approximately one-third of all AML patients, not only signifies a poorer prognosis but also identifies an important target for therapy. FLT3 inhibitors have now undergone clinical evaluation in Phase I, II and III clinical trials, as both single agents and in combination with chemotherapeutics. Unfortunately, to date, none of the FLT3 inhibitors have gained FDA approval for the treatment of patients with AML. Yet, several promising FLT3 inhibitors are being evaluated in all phases of drug development.

Areas covered: This review aims to highlight the agents furthest along in their development. It also focuses on those FLT3 inhibitors that are being evaluated in combination with other anti-leukemia agents.

Expert opinion: The authors believe that the field of research for FLT3 inhibitors remains promising, despite the historically poor prognosis of this subgroup of patients with AML. The most promising areas of research will likely be the elucidation of the mechanisms of resistance to FLT3 inhibitors, and development of potent FLT3 inhibitors alone or in combination with hypomethylating agents, cytotoxic chemotherapy or with other targeted agents.     

小分子EGFR酪氨酸激酶抑制剂盐酸埃罗替尼

盐酸埃罗替尼是一种小分子表皮生长因子酪氨酸激酶可逆抑制剂,通过抑制酪氨酸激酶的磷酸化,阻断信号传导,抑制肿瘤生长.临床前研究表明其对表皮生长因子酪氨酸激酶有抑制作用;临床研究显示该药对多种肿瘤有抗肿瘤活性,不良反应较轻,与化疗药物合用不增加毒性.2004年经FDA批准上市,用于一线化疗失败的局部晚期或转移性非小细胞肺癌的治疗.     

一种新的细胞周期蛋白依赖性激酶(CDK)9抑制剂QHRD107对急性髓系白血病的临床前疗效

QHRD107是细胞周期蛋白依赖性激酶(CDK)9的特异性抑制剂.体外对白血病细胞增殖具有高度抑制作用,在急性髓系白血病异种移植模型体内显著抑制肿瘤细胞生长,并能显著延长小鼠寿命.Molm-13异种移植模型单次灌胃给予QHRD107后,QHRD107迅速被吸收并靶向性分布至肿瘤组织,肿瘤半衰期(T1/2)较血浆延长3倍...     

表皮生长因子受体酪氨酸激酶抑制剂吉非替尼

吉非替尼(ZD1839,Iressa)是一种表皮生长因子受体酪氨酸激酶抑制剂,通过阻断酪氨酸激酶信号传导通路抑制肿瘤生长.2个大型的Ⅱ期临床试验(IDEAL)证实了其对于晚期非小细胞肺癌具有应用前景,可以改善症状,延长患者的生存期.此外,在对多种恶性实体瘤的Ⅰ期和Ⅱ期临床研究中也初步证实了该药具有抗肿瘤活性.     

Targets and effectors of the cellular response to aurora kinase inhibitor MK-0457 (VX-680) in imatinib sensitive and resistant chronic myelogenous leukemia

MK-0457 inhibits aurora, BCR-ABL and other kinases and may be clinically active in imatinib resistant leukemia. To define mediators of MK-0457 responsiveness, kinase inhibitory profiles were examined in multiple cell models of imatinib sensitive and resistant disease. Aurora and BCR-ABL kinase inhibition were consistently measured at 20-100 nM and 2-10 μM MK-0457, respectively, but expression of T315I-BCR-ABL and overexpression of Lyn kinase reduced MK-0457 sensitivity. Aurora kinase inhibition was associated with cell cycle restriction and p53 induction and p53-null cells were far less responsive to MK-0457, requiring BCR-ABL inhibitory concentrations for apoptotic activity. In wild-type p53 expressing CML cells MK-0457 sensitivity was modulation by alterations in p53 levels through HDM-2 inhibition and gene silencing. MK-0457 suppressed aurora kinase activity and induced apoptosis in imatinib resistant clinical specimens expressing T315I and other BCR-ABL mutations without effecting BCR-ABL kinase activity. Together, these results suggest that MK-0457 apoptotic activity in CML cells is primarily associated with aurora kinase inhibition but can be altered by multiple molecular changes associated with disease progression or acquisition of imatinib resistance.     

多靶点激酶抑制药GNF-7对白血病细胞表达谱的影响

目的探索多靶点激酶抑制药GNF-7对白血病细胞表达谱的影响。方法从基因表达公共数据库下载表达谱数据集GSE49534,用BRB-Array Tools软件包筛选差异表达基因(DEGs),分别对差异基因进行基因本体(GO)功能分析、通路富集分析、基因互作网络分析和通路互作网络分析。结果共筛选出847个差异基因,其中上调表达基因426个,下调表达基因419个。DEGs发挥的分子功能集中在结合、蛋白激酶活性和信号转导因子活性等,主要参与信号转导、小分子代谢和细胞凋亡等生物学过程。DEGs显著富集的通路有核糖体合成、代谢通路、Janus激酶-信号转导和转录激活因子(JAK-STAT)信号通路等。网络分析挖掘出的核心基因有多核糖核苷酸核苷酸转移酶1(PNPT1)、腺苷酸激酶4(AK4)、Janus激酶2(JAK2)、信号转导和转录激活因子2(STAT2)、MYC,核心pathway包括丝裂原活化蛋白激酶(MAPK)信号通路、凋亡、细胞周期和肿瘤通路等。结论 GNF-7通过诱导凋亡和细胞周期阻滞等抑制白血病细胞。     

Nilotinib for the treatment of Philadelphia-chromosome-positive chronic myeloid leukemia

Importance of the field: Although the introduction of imatinib revolutionized the management of chronic myeloid leukemia (CML), some patients exhibit resistance or intolerance to the drug. Nilotinib induces high and rapid rates of cytogenetic and molecular responses. With recent approval for newly diagnosed patients with chronic phase CML, the current algorithm for treatment will probably be transformed.

Areas covered in this review: This review will describe evaluations of nilotinib in all phases of CML from 1995 to the present. Early preclinical data and Phase I, Phase II and Phase III evaluations will demonstrate the role of nilotinib in newly diagnosed CML, as well as in imatinib-resistant or imatinib-intolerant disease.

What the reader will gain: Mutations in the BCR-ABL kinase domain are responsible for the majority of resistance to imatinib. In comparison with imatinib, nilotinib displays increased selectivity and potency at inhibiting proliferation of BCR-ABL expressing cells. Although several mutations, including T315I, remain resistant to nilotinib, activity in all phases of CML has been reported.

Take home message: Nilotinib induces high and rapid rates of cytogenetic and molecular response, with less progression to advanced forms of disease compared with imatinib. Considering that the rapid achievement of these clinical milestones has been associated with positive long-term outcomes, nilotinib as initial therapy in patients with CML in chronic phase represents the future in CML treatment. Longer follow-up is necessary to recognize survival advantages.     

COX-2特异性抑制剂依托考昔对白血病化疗增效作用的体外研究

目的 研究COX-2抑制剂与化疗药物合用对白血病细胞株杀伤作用的影响.方法 改良MTT法检测Jurkat、K562、K562/A02白血病细胞株分别用化疗药物多柔比星、柔红霉素、长春新碱、阿糖胞苷、门冬酰胺酶、地塞米松诱导凋亡及联用COX-2特异性抑制剂依托考昔后IC50及药物抑制曲线的改变,金氏方程计算药物联用的增效作用.结果 Jurkat、K562及K562/AO2细胞株单独加依托考昔时,均未出现生长抑制,Jurkat联用依托考昔及多个浓度的多柔比星、柔红霉素、长春新碱或门冬酰胺时,均比化疗药单独使用时抑制率提高(Q≥1.15);联用依托考昔及地塞米松时抑制率降低,表现出拮抗作用(Q＜0.85);K562联用多个浓度的阿糖胞苷、多柔比星或柔红霉素时,表现出协同作用(Q≥1.15);K562/AO2联用依托考昔及多柔比星时,表现出协同作用(Q≥1.15).结论 COX-2特异性抑制剂依托考昔不能直接抑制白血病细胞,在体外化疗药物作用于白血病细胞株时,加依托考昔表现出增效作用.     

The expanding role of nilotinib in chronic myeloid leukemia

Importance of the field: Several therapeutic options, including tyrosine kinase inhibitors, exist for the treatment of patients with Philadelphia chromosome (Ph)-positive chronic myeloid leukemia (CML). Despite impressive results, there is room for improvement for those patients who are either resistant or intolerant to imatinib.

Areas covered in this review: An overview is given on the clinical results with nilotinib, a rationally designed second-generation tyrosine kinase inhibitor, as first- and second-line therapy in patients with Ph-positive CML. Important factors in predicting resistance to nilotinib and guiding therapeutic decisions are addressed.

What the reader will gain: Knowledge on the clinical efficacy and safety of nilotinib after imatinib failure and as first-line treatment. Point mutations in the kinase domain (KD) of BCR-ABL1 are important determinants of clinical sensitivity to currently available tyrosine kinase inhibitors, including nilotinib. Information on specific BCR-ABL1 KD mutations and safety profiles assist in therapeutic decision making.

Take home message: Nilotinib is a highly effective and well-tolerated therapeutic option in patients with Ph-positive CML after imatinib failure. Early evidence demonstrating increased efficacy has allowed expanding nilotinib to previously untreated patients in chronic phase. Insights into mechanisms of resistance to tyrosine kinase inhibitors and predictive factors for response will allow for a more individualized use of these agents.     

检查点激酶Bub1抑制剂2OH-BNPP1的合成研究

目的：研究检查点激酶Bub1抑制剂2OH-BNPP1的合成方法。方法：将2-羟基苯乙酸转化成苄基保护的酰氯,再与丙二腈缩合得化合物5,经硫酸二甲酯对5的烯醇式甲基化得化合物6,6与叔丁基肼反应完成了吡唑环的构筑以形成化合物7,7与甲酰胺作用构筑并嘧啶环,最后将所得的化合物8脱苄,即得目标物1。结果与结论：以苄基保护起始原料的2-位酚羟基,使路线中的各步中间体稳定、极性小而易于硅胶柱色谱分离,最后催化脱苄几乎定量完成,保证了终产物的化学纯度。目标物的HPLC检测纯度为98.8 %,其结构经ESI&;#61485;MS和1H&;#61485;NMR确证。     

早幼粒细胞白血病蛋白在髓系白血病中的表达及其对慢性粒细胞白血病增殖的影响分析

目的 探讨早幼粒细胞白血病(PML)蛋白在髓系白血病中的表达情况及其对慢性粒细胞白血病细胞增殖的抑制作用.方法 收集髓系白血病患者(髓系白血病组)60例,非肿瘤性血液病患者(对照组)15例,患者骨髓制备石蜡切片,采用免疫荧光技术观察PML在细胞内的分布和表达;提取骨髓单核细胞总RNA,采用逆转录聚合酶链反应观察PML mRNA的表达情况;提取骨髓总蛋白,采用蛋白质印迹法(Western Blot)观察PML蛋白的表达情况;K562细胞分别转染空质粒(MSCV组)、截短失活PML(DN组)和野生型PML(Wt组),测定PML基因对K562细胞增殖和集落产生的影响.结果 非肿瘤性血液病患者的PML表达聚集在细胞核内,而髓系白血病患者的PML分散表达在细胞核和胞质内;髓系白血病组PML mRNA水平0.356±0.092显著低于对照组的表达0.536±0.066(t=7.11,P<0.01);髓系白血病组PML蛋白相对表达水平0.189±0.032显著低于对照组0.323±0.025(t=16.10,P<0.01);DN(转染截短失活PML)组,MSCV(转染空质粒)组和Wt(转染野生型PML)组在450 nm波长下吸光度值(Optical Density450,OD450)和集落生成单位(Colony-Forming Units,CFU)的数据均差异有统计学意义(F=34.28,25.39,P<0.05),q检验结果显示,均为Wt组的数值低于DN组和MSCV组.结论 髓系白血病患者中PML蛋白表达水平下降导致细胞异常增殖可能是其发病机制.     

An open-label,single-dose,phase 1 study of the absorption,metabolism and excretion of quizartinib,a highly selective and potent FLT3 tyrosine kinase inhibitor,in healthy male subjects,for the treatment of acute myeloid leukemia

1. Quizartinib absorption, metabolism and excretion were characterized in six healthy men receiving a single oral dose of 60?mg (≈100?μCi) of [¹⁴C]-quizartinib. Blood, plasma, urine and faeces were collected ≤336?h postdose.

2. Four hours postdose, maximum mean?±?SD blood radioactivity concentrations were 296?±?67.4?ng equivalents/g. A mean?±?SD of 1.64?±?0.482% and 76.3?±?6.23% of the dose was recovered in urine and faeces, respectively, within 336?h postdose.

3. Radio-detector high-performance liquid chromatography (radio-HPLC) and liquid chromatography–mass spectrometry (LC–MS) showed two main radioactive peaks in plasma, unchanged quizartinib and mono-oxidative metabolite, AC886. Five additional metabolites in plasma were identified by LC–MS, but low levels prevented radio-HPLC detection. Although unchanged quizartinib was the main radioactive component in faeces (mean, 4.0% of administered dose), 15 metabolites representing a mean of 1.0–3.5% of administered dose were found. Quizartinib was predominantly metabolized by phase I biotransformations (oxidation, reduction, dealkylation, deamination, hydrolysis and combinations thereof).

4. This study indicated that quizartinib was rapidly and orally bioavailable, extensively metabolized, with AC886 as the major circulating metabolite, and predominantly eliminated in faeces. Quizartinib was well tolerated in the subjects.     

Aurora kinase targeted therapeutics in oncology: past,present and future

Aurora A, B and C are a family of serine-threonine protein kinases that regulate distinct functions of the mitotic phase of the cell cycle. All three Auroras are overexpressed in human cancers with an associated polyploid phenotype. Crystal structures of Aurora A or B with bound small molecular inhibitors have provided detailed insight of the active site, mode of binding and hotspots for developing resistance through point mutations. Structural studies have aided fragment-based rational drug discovery of Aurora inhibitors, including compounds specific for Aurora A or B. Aurora inhibitors have excellent antitumor activity in rodent models of cancer. At present, Aurora inhibitors are being evaluated in Phase I trials. The future holds promise for rational combinations in both solid and hematological malignancies.