Mcl-1小分子抑制剂研究进展

MCL-1(myeloid cell leukemia-1)蛋白是BCL-2(B-cell lymphoma-2)蛋白家族中重要的抗凋亡蛋白成员之一,在多种肿瘤细胞中过表达。Mcl-1蛋白的过表达不仅与肿瘤的发生发展密切相关,还会导致肿瘤细胞对化疗药物产生耐药性,因此以Mcl-1为靶点的小分子抑制剂是未来抗肿瘤药物研发的重点。本文对2012-2017年间发表的Mcl-1小分子抑制剂进行了综述,主要介绍小分子抑制剂的化学结构和生物活性,旨在为Mcl-1小分子抑制剂的深入研究以及更多海洋来源的新型Mcl-1小分子抑制剂的开发提供参考。     

Mcl-1蛋白的结构、功能及其抑制剂的研究进展

细胞凋亡与许多人类疾病的发生密切相关,过度凋亡引发神经退行性疾病,而抑制凋亡则与肿瘤等疾病的产生有关.研究表明,Bcl-2蛋白家族在细胞凋亡中发挥重要作用,特别是近几年对Bcl-2蛋白家族成员Mcl-1及其抑制剂研究越来越多.本文介绍了Mcl-1蛋白的结构与功能特点,综述了近几年作为抗肿瘤药物的Mcl-1抑制剂的研究进展.     

姜黄素的免疫调节作用及其肿瘤免疫治疗的研究进展

癌症发病率逐年增长,且死亡率居高不下。肿瘤免疫治疗作为目前肿瘤治疗领域中最具前景的研究方向之一,其治疗手段主要包括过继性细胞治疗、免疫调节治疗、肿瘤疫苗治疗、分子靶向治疗等。姜黄素是姜黄中主要活性成分,主要通过抑制细胞增殖、诱导细胞凋亡、抑制肿瘤侵袭等机制发挥抗肿瘤功效。在免疫治疗领域,姜黄素通过调节机体的固有免疫系统、获得性免疫系统以及肿瘤相关分子的表达和活性达到抗肿瘤作用,并联合免疫检查点抑制剂、其他肿瘤免疫治疗方法用于肿瘤治疗。总结了姜黄素的免疫调节作用及其用于肿瘤免疫治疗的研究进展。     

欧前胡素对顺铂的骨肉瘤细胞抗肿瘤作用的增效作用

目的 研究欧前胡素是否能提高人骨肉瘤细胞(human osteosarcoma cells,HOS细胞)对顺铂的敏感性。方法 HOS细胞用欧前胡素和顺铂处理,MTT法检测体外细胞活力,Western blot检测Bcl-2 蛋白家族成员(Mcl-1、Bcl-2、Bcl-xl、Bad和Bax)的表达水平,流式细胞术检测细胞凋亡水平和线粒体膜电位的变化情况。构建Mcl-1真核表达载体,MTT法检测Mcl-1表达载体转染对欧前胡素联合顺铂治疗骨肉瘤疗效的影响。结果 欧前胡素在体外可显著提高顺铂对骨肉瘤细胞系HOS的杀伤活性。欧前胡素可显著降低HOS细胞Mcl-1的表达,而顺铂对Mcl-1的表达水平无影响。相比于欧前胡素或顺铂单治疗组,两者联合可显著诱导HOS细胞发生凋亡并降低其线粒体膜电位。体外转染Mcl-1真核表达载体显著降低顺铂联合欧前胡素对HOS细胞的杀伤活性。结论 欧前胡素通过靶向于Mcl-1增强顺铂对骨肉瘤细胞的杀伤活性。     

索拉菲尼增强TRAIL 诱导人肝癌细胞凋亡的作用及机制探讨

目的观察索拉菲尼(Sorafenib)是否能增强肿瘤坏死因子相关凋亡诱导配体(TRAIL)诱导人肝癌细胞凋亡并探讨其作用机制。方法体外培养人肝癌HepG2细胞,MTT法测定细胞增殖活性,碘化丙啶(PI)染色流式细胞术(FCM)和细胞凋亡ELISA检测试剂盒检测细胞凋亡,Western blotting分析Mcl-1的表达。结果索拉菲尼具有增强TRAIL诱导人肝癌HepG2细胞凋亡的作用,并呈剂量和时间依赖的方式抑制Mcl-1的表达。Mcl-1过表达能抑制索拉菲尼增强TRAIL诱导HepG2细胞凋亡的作用。结论索拉菲尼通过抑制Mcl-1的蛋白表达增强TRAIL诱导人肝癌细胞凋亡的作用。     

选择性B—Raf激酶抑制剂的研究进展

随着细胞分子生物学的发展,肿瘤的分子靶向治疗已成为目前抗肿瘤药物研究的重要领域之一。其中Raf激酶,特刊是B-Raf由于在肿瘤中的突变率高,是目前抗肿瘤药物研充的重要靶点之一。一些Raf抑制剂在早期临床研究中有特犀性抑制活性,显现其具有良好的临床应用前景。     

非喜树碱类DNA拓扑异构酶Ⅰ抑制剂的研究进展

DNA拓扑异构酶Ⅰ（TopoⅠ）是抗肿瘤治疗的重要靶点。喜树碱类TopoⅠ抑制剂已在肿瘤的临床治疗中被广泛使用,但受分子骨架制约,其存在水溶性低、稳定性差、毒副作用大等缺点,而具有新颖结构的非喜树碱类TopoⅠ抑制剂则有望克服这些缺点。按结构分类综述非喜树碱类TopoⅠ抑制剂的抗肿瘤活性及构效关系研究新进展。     

基于分子对接、定量构效关系和分子动力学研究筛选小分子SIRT1抑制剂

为了寻找和发现靶向SIRT1的治疗AML的新型先导化合物,本研究利用分子对接与MM-GBSA结合自由能计算进行虚拟筛选,从231511个天然小分子类药分子库中筛选出8个潜在的SIRT1抑制剂,通过对已有的SIRT1抑制剂分子作为训练集和测试集进行QSAR建模,对筛选出的潜在SIRT1抑制剂分子进行活性预测,随后进行分子动力学模拟验证这些潜在抑制剂与SIRT1蛋白的结合模式与稳定性,最后通过OCI-AML2、OCI-AML3和MV4-11三种AML细胞增殖实验和SIRT1酶活性验证了这些分子的生物活性,发现其中5个分子对3种AML细胞具有不同程度的抑制作用,其中活性最强的化合物ZINC000001774455对AML细胞OCI-AML2的IC50达到2.29±0.09μmol·L^-1μmol·L^-1浓度下对SIRT1抑制率为65.33%,可作为SIRT1抑制剂先导化合物进行结构修饰,为开发新的AML治疗药物奠定了前期基础。     

miR-363对顺铂耐药乳腺癌细胞的作用及机制

目的 研究miR-363对顺铂耐药乳腺癌细胞的作用及机制。方法 采集以顺铂为主要化疗药物的中晚期乳腺癌患者血清,用定量PCR法检测化疗前和化疗后血清标本miR-363的表达水平。构建顺铂抵抗MCF-7细胞系(MCF-7-R),MTT法检测不同浓度顺铂对MCF-7及MCF-7-R细胞活力的影响。在MCF-7-R细胞中转染miR-363,MTT法检测miR-363是否能提高顺铂对MCF-7-R的杀伤活性。利用生物信息学、定量PCR及western blot方法验证miR-363是否调节MCF-7-R细胞中Mcl-1的表达。构建Mcl-1真核表达载体,MTT法检测Mcl-1表达载体转染对miR-363联合顺铂治疗MCF-7-R疗效的影响。结果 中晚期乳腺癌患者顺铂治疗后血清miR-363水平相较化疗前显著下降。MTT结果表明相同浓度顺铂对MCF-7-R的杀伤活性显著低于MCF-7细胞,且miR-363转染能显著提高顺铂对MCF-7-R的杀伤活性。生物信息学、定量PCR及western blot结果表明miR-363转染可显著降低MCF-7-R细胞中Mcl-1的表达。miR-363联合顺铂在Mcl-1表达载体转染后对MCF-7-R细胞的杀伤活性显著低于未转染Mcl-1表达载体的miR-363联合顺铂组。结论 MiR-363能增强耐顺铂乳腺癌细胞对顺铂杀伤作用的敏感性。     

应用组织芯片技术研究胃癌组织中Mcl-1蛋白的表达及其意义

目的探讨胃癌组织髓样细胞白血病蛋白-1(Mcl-1)蛋白的表达与临床病理特征的相关性及其与胃癌发生、发展的关系。方法用组织芯片和免疫组化的方法检测148例胃癌组织、20例胃正常组织(含正常胃黏膜组织及癌旁正常胃组织)中Mcl-1蛋白的表达。结果胃癌组织、胃正常组织中均有Mcl-1蛋白的表达,定位于细胞浆中,着色呈淡黄色至深棕色;胃癌组织、胃正常组织Mcl-1蛋白阳性表达率分别为83.78%(124/148)、60.00%(12/20),差异具有统计学意义(χ2=6.464,P=0.011)。胃癌组织中Mcl-1蛋白的表达随肿瘤分化程度的降低而增强,与是否伴有淋巴结转移相关;但与患者的年龄、性别、肿瘤大小、浸润深度等无关。结论胃癌组织中Mcl-1蛋白的表达增高,与胃癌的发生、分化程度、淋巴结转移密切相关。     

Mechanism of Mcl‐1 Conformational Regulation Upon Small Molecule Binding Revealed by Molecular Dynamic Simulation

Inhibition of interactions between Mcl‐1 and proapoptotic proteins is considered to be a therapeutic strategy to induce apoptosis in cancer cells. Here, we adopted molecular dynamics simulation with molecular mechanics–Poisson Boltzmann/surface area method (MM‐PB/SA) to study the inhibition mechanism of three Mcl‐1 inhibitors, compounds 1 , 2 and 3 . Analysis of energy components shows that the better binding free energy of compound 3 than compounds 1 and 2 is attributable to the van der Waals energy (ΔE_vdw) and non‐polar solvation energy (ΔG_np) upon binding. In addition to the excellent agreement with previous experimentally determined affinities, our simulation results further show a bend of helix 4 on Mcl‐1 upon compound 3 binding, which is driven by hydrophobic interaction with residue Val²⁵³, leading to a narrowed BH3‐binding groove to impede Puma^BH3 binding. The computational result is consistent with our competitive isothermal titration calorimetry (ITC) assays, which shows that the competitive ability of compound 3 toward Mcl‐1/Puma^BH3 complex is improved beyond its direct binding affinity toward Mcl‐1 itself, and compound 3 exhibits much more efficiency to compete with Puma^BH3 than compound 2 . Our study provides a new strategy to improve inhibitory activity on Mcl‐1 based on the conformational dynamic change.     

Targeting human MutT homolog 1 (MTH1) for cancer eradication: current progress and perspectives

Since accelerated metabolism produces much higher levels of reactive oxygen species (ROS) in cancer cells compared to ROS levels found in normal cells, human MutT homolog 1 (MTH1), which sanitizes oxidized nucleotide pools, was recently demonstrated to be crucial for the survival of cancer cells, but not required for the proliferation of normal cells. Therefore, dozens of MTH1 inhibitors have been developed with the aim of suppressing cancer growth by accumulating oxidative damage in cancer cells. While several inhibitors were indeed confirmed to be effective, some inhibitors failed to kill cancer cells, complicating MTH1 as a viable target for cancer eradication. In this review, we summarize the current status of developing MTH1 inhibitors as drug candidates, classify the MTH1 inhibitors based on their structures, and offer our perspectives toward the therapeutic potential against cancer through the targeting of MTH1.     

Overview of ribonucleotide reductase inhibitors: an appealing target in anti-tumour therapy

This review provides up-to-date information on the inhibition of ribonucleotide reductase (RNR), the enzyme that catalyses the reduction of ribonucleotides into deoxyribonucleotides. Taking in account that DNA replication and repair are essential mechanisms for cell integrity and are dependent on the availability of deoxyribonucleotides, many researchers are giving special attention to this enzyme, since it is an attractive target to treat several diseases of our time specially cancer. This investment has already given some benefits since some of these inhibitors show potent chemotherapeutic efficacy against a wide range of tumours such as non-small cell lung cancer, adenocarcinoma of pancreas, bladder cancer, leukaemia and some solid tumours. In fact a few of them have already been approved for the clinical treatment of some kinds of cancer. All aspects of RNR inhibition and corresponding inhibitors are the subjects of this review. The inhibitors are divided in three main groups: translation inhibitors, which unable the formation of the enzyme; dimerization inhibitors that prevent the complexation of the two RNR subunits (R1 and R2); and catalytic inhibitors that inactivate subunit R1 and/or subunit R2, leading to RNR inactivity. In this last group special focus will be addressed to substrate analogues.     

Arylazopyrazole AAP1742 Inhibits CDKs and Induces Apoptosis in Multiple Myeloma Cells via Mcl‐1 Downregulation

Inhibitors of cyclin‐dependent kinases 9 have been developed as potential anticancer drugs for the treatment of multiple myeloma. We have previously prepared a library of arylazo‐3,5‐diaminopyrazole inhibitors of CDKs. Here, we describe a novel member, AAP1742 (CDK9 inhibition with IC₅₀ = 0.28 μm ), that reduces the viability of multiple myeloma cell lines in low micromolar concentrations. Consistent with inhibition of CDK9, AAP1742 decreases the phosphorylation of RNA polymerase II and inhibits mRNA synthesis of anti‐apoptotic proteins Mcl‐1, Bcl‐2, and XIAP, followed by apoptosis in the RPMI‐8226 cell line in a dose‐ and a time‐dependent manner. These results are consistent with the biochemical profile of AAP1742 and further suggest cellular inhibition of CDK9 as a possible target for anticancer drugs.     

Heat‐Shock Protein 90 (Hsp90) as Anticancer Target for Drug Discovery: An Ample Computational Perspective

There are over 100 different types of cancer, and each is classified based on the type of cell that is initially affected. If left untreated, cancer can result in serious health problems and eventually death. Recently, the paradigm of cancer chemotherapy has evolved to use a combination approach, which involves the use of multiple drugs each of which targets an individual protein. Inhibition of heat‐shock protein 90 (Hsp90) is one of the novel key cancer targets. Because of its ability to target several signaling pathways, Hsp90 inhibition emerged as a useful strategy to treat a wide variety of cancers. Molecular modeling approaches and methodologies have become ‘close counterparts’ to experiments in drug design and discovery workflows. A wide range of molecular modeling approaches have been developed, each of which has different objectives and outcomes. In this review, we provide an up‐to‐date systematic overview on the different computational models implemented toward the design of Hsp90 inhibitors as anticancer agents. Although this is the main emphasis of this review, different topics such as background and current statistics of cancer, different anticancer targets including Hsp90, and the structure and function of Hsp90 from an experimental perspective, for example, X‐ray and NMR, are also addressed in this report. To the best of our knowledge, this review is the first account, which comprehensively outlines various molecular modeling efforts directed toward identification of anticancer drugs targeting Hsp90. We believe that the information, methods, and perspectives highlighted in this report would assist researchers in the discovery of potential anticancer agents.     

Targeting HIV protease: from peptidomimetics to non-peptide inhibitors

The identification of HIV-1 protease as a target for therapeutic intervention against AIDS, soon followed by the resolution of its three-dimensional structure, has had a major impact on drug-design methodologies. The possible HIV-1 protease inhibitors that have been synthesized number in the thousands and exhibit amazing chemical diversity, but only a few happen to be useful for human therapy. This review covers the development of some of these inhibitors, the reasons for this limited success, current therapeutic problems and challenges remaining ahead.     

Discovery of Novel Allosteric Eg5 Inhibitors Through Structure‐Based Virtual Screening

Mitotic kinesin Eg5 is an attractive anticancer drug target. Discovery of Eg5 inhibitors has been focused on targeting the ‘monastrol‐binding site’. However, acquired drug resistance has been reported for such inhibitors. Therefore, identifying new Eg5 inhibitors which function through a different mechanism(s) could complement current drug candidates and improve drug efficacy. In this study, we explored a novel allosteric site of Eg5 and identified new Eg5 inhibitors through structure‐based virtual screening. Experiments with the saturation‐transfer difference NMR demonstrated that the identified Eg5 inhibitor SRI35566 binds directly to Eg5 without involving microtubules. Moreover, SRI35566 and its two analogs significantly induced monopolar spindle formation in colorectal cancer HCT116 cells and suppressed cancer cell viability and colony formation. Together, our findings reveal a new allosteric regulation mechanism of Eg5 and a novel drug targeting site for cancer therapy.     

Camptothecin induces apoptosis in cancer cells via microRNA-125b-mediated mitochondrial pathways

Camptothecin (CPT) is an effective chemotherapeutic agent for treatment of patients with cancer. The mechanisms underlying CPT-mediated responses in cancer cells are not fully understood. MicroRNA (miRNA) play important roles in tumorigenesis and drug sensitivity. However, the interaction between camptothecin and miRNA has not been previously explored. In this study, we verified that miR-125b was down-regulated in CPT-induced apoptosis in cancer cells and that ectopic expression of miR-125b partially restored cell viability and inhibited cell apoptosis that was induced by CPT. In addition, we demonstrated that CPT induced apoptosis in cancer cells by miR-125b-mediated mitochondrial pathways via targeting to the 3'-untranslated (UTR) regions of Bak1, Mcl1, and p53. A significant increase in Bak1, Mcl1, and p53 protein levels was detected in response to the treatments of CPT. It is noteworthy that the expression levels of Bak1, Mcl1, and p53 increased in a time-dependent manner and negatively correlated with miR-125b expression. It is noteworthy that we revealed that miR-125b directly targeted the 3'UTR regions of multiple genes in a CPT-induced mitochondrial pathway. In addition, most targets of miR-125b were proapoptotic genes, whereas some of the targets were antiapoptotic genes. We hypothesized that miR-125b may mediate the activity of chemotherapeutic agents to induce apoptosis by regulating multiple targets. This is the first report to show that camptothecin induces cancer cell apoptosis via miRNA-mediated mitochondrial pathways. The results suggest that suppression of miR-125b may be a novel approach for the treatment of cancer.     

Targeting multiple kinases in glioblastoma multiforme

Glioblastoma multiforme (GBM), the most common primary malignant brain tumor in adults, is associated with high mortality. Current standard-of-care treatments, including surgery, radiation and chemotherapy, offer only palliation. Recent research in cancer therapy has shifted towards targeting the specific molecular aberrations that underlie the pathogenesis of cancers including GBM. Protein kinases are a family of enzymes that are key components in regulating cellular homeostasis. Protein kinases can be deregulated by several mechanisms, which contribute to cancer initiation and maintenance. Several protein kinases are important in gliomagenesis, thus representing new therapeutic targets in GBM. Low molecular weight inhibitors are the most commonly used agents to target protein kinases in the treatment of cancers. However, first-generation kinase inhibitors targeting only single kinases have demonstrated limited efficacy in unselected GBM patient populations. Several mechanisms of failure of monotherapy with single-targeted kinase inhibitors have been explained as new therapeutic strategies have emerged to overcome resistance. Simultaneous disruption of several kinases can be achieved by either multitargeted kinase inhibitors or combination of single-targeted kinase inhibitors with one another or with traditional cytotoxics. In this review, we will discuss the current clinical status of targeted therapy in GBM and recent approaches to target multiple kinases in this devastating cancer.     

Current and future directions in mammalian target of rapamycin inhibitors development

INTRODUCTION: The mammalian target of the rapamycin (mTOR) signalling pathway has a central role in the regulation of cell growth, survival and angiogenesis and the frequent dysregulation of this pathway in tumor cells makes it a crucial target in the treatment of cancer. Temsirolimus and everolimus are approved for use in metastatic renal cell carcinoma and temsirolimus is also approved for mantle cell lymphoma. All three rapalogs, temsirolimus, everolimus and deforolimus, are currently being evaluated in Phase III studies in several tumors. AREAS COVERED: This paper provides a review of the published literature on the mTOR pathway and related pathway signaling, analogs and novel mTOR inhibitors. The most recent and important data on the mTOR pathway, the role of mTOR inhibitors in cancer treatment and the current status of development of second-generation highly potent and selective mTOR inhibitors are overviewed. EXPERT OPINION: The published data on new mTOR inhibitors are still limited, but the available preclinical results indicate that they have a potent antiproliferative activity against a broad panel of tumor cell lines, have a favorable safety profile, can obtain disease stabilization or even tumor regression and, in some cases, enhance the efficacy of other targeted or standard-of-care anticancer drugs when used in vivo in preclinical studies.