金属氮杂环卡宾配合物的抗肿瘤活性研究进展

自1978年顺铂成功地被开发成癌症临床治疗药物以来,金属配合物作为小分子抗癌药物的开发成为人们的研究热点。其中,氮杂环卡宾能与多种过渡金属中心形成稳定的共价键,这种特殊的稳定性使得金属氮杂环卡宾配合物具有被开发成药物的潜能。近年来,金属氮杂环卡宾配合物被发现具有良好的抗癌活性,激发了广大无机药物化学研究者的研究热情。综合笔者课题组在金属氮杂环卡宾抗肿瘤配合物方面的前期研究,本文将对银、金、铑和铂氮杂环卡宾配合物的抗肿瘤活性及作用机制进行综述,以期为新型金属氮杂环卡宾抗肿瘤化合物的设计合成提供参考。     

Rational design of multi-targeting ruthenium- and platinum-based anticancer complexes

Platinum-based anticancer drugs, including cisplatin and its analogues, have played important roles in the clinical treatment of solid tumors over the past 38 years. However, poor selectivity, high toxicity and intrinsic or acquired drug resistance profoundly limit their application, which encourages the development of novel transition metal-based anticancer agents with different mechanisms of action. To this end, transition metal complexes that can simultaneously act on more than one target, termed as single-molecule multi-targeting complexes, have attracted increasing attention because of their enhanced efficacy and diminished chance of drug resistance. In this review, we systematically discuss the recent progress in the development of platinum- and ruthenium-based anticancer agents, in particular the rational design of platinum and ruthenium complexes with multi-targeting features.     

Anticancer platinum‐based complexes with non‐classical structures

Although classical platinum drugs such as cisplatin, carboplatin and oxaliplatin play a vitally important role in cancer treatment, nonselective distribution of platinum drugs in normal and tumor cells can induce serious gastrointestinal reaction, nephrotoxicity, ototoxicity, neurotoxicity and cross resistance, limiting their applications. Over the past few years, a great number of platinum complexes of non‐classical structures have been extensively investigated and evaluated in vitro and in vivo, some of them exhibiting considerable activity. In this review, platinum‐based complexes with non‐classical structures which have anticancer potential are described and several representative examples are discussed with their mechanism of action.     

钯(Ⅱ)类抗肿瘤药物研究进展

20世纪60年代,美国密执安州立大学Rosenberg发现了顺铂具有抗癌活性,开辟了金属类抗肿瘤药物研究的新领域.经过40余年的研究,已相继成功开发了卡铂、奈达铂、奥沙利铂、舒铂、洛铂和双环铂等铂类抗肿瘤药物.虽然对于铂类抗肿瘤药物研究取得了一定的成绩,但在临床使用过程中也存在一些问题,如其毒副作用和抗药性,限制了其在临床上的进一步广泛应用.为了解决这些问题,科研工作者开始寻找新的金属类抗肿瘤药物以弥补现有铂类抗肿瘤药物的不足.在金属元素中,唯有钯(II)与铂(II)配合物具有相似或相同的结构特征,进而表现出相近或相似的化学性质.因此,继铂类抗肿瘤配合物后,钯(II)配合物作为潜在抗肿瘤药物成为一个诱人的领域.本文综述了近年来钯(II)类抗肿瘤药物的研究进展,并探讨了其构效关系,这对于指导新型钯(II)类抗肿瘤药物的合成具有重要的参考价值.     

Recent advancements in the anticancer potentials of first row transition metal complexes

The frequently severe effects of currently utilized platinum-based complexes have prompted researchers to develop less toxic transition metal based anticancer drugs. Transition metal complexes have recently gained considerable attention as promising anticancer agents due to their efficient drug design and fast optimisation. Some transition metal complexes displayed better anticancer activity than cis-platin. This led to the transition metal complexes for clinical application of chemotherapeutic drugs for cancer therapy. Cytotoxicity of the complexes has been evaluated on the basis of their IC₅₀ values. In this review, we have focussed on recent findings about the anticancer mechanism of action of first row transition metal complexes during the last ten years.     

金属抗癌药物设计的新策略和新趋势*

金属药物有许多其它药物无法比拟的独特性质,以顺铂为代表的铂类抗癌药物在癌症临床化疗中发挥了巨大作用。但是铂类药物的毒副作用严重限制了它们的实际疗效和适用范围,因此需要继续研究具有不同作用机理的新型金属抗癌药物,以改良或补充现有铂类药物的性能。本文重点介绍了近年来设计金属抗癌药物的一些新策略,包括改变铂类药物与DNA的作用模式、改进铂类药物对肿瘤的靶向性、研发非铂类金属抗癌药物和寻找DNA以外的作用靶标等。这些内容体现了该领域的最新发展趋势,为从事金属抗癌药物开发研究的科技人员提供了有益的参考信息。     

New Cisplatin Analogues—On the Way to Better Antitumor Agents

The clinical success of cisplatin (cis -diamminedichloroplatinum(II )) in antitumor chemotherapy has encouraged an all-out search for analogues with lower toxicity, improved therapeutic index and increased activity. Literally thousands of analogues, obtained by replacement of the ammine- and chloro-ligands by other amines and anionic ligands, respectively, have been systematically screened for activity in experimental tumor models. Some of these analogues have been selected for clinical evaluation, but only very few of them appear to be promising antitumor agents. More recently, cisplatin analogues have been designed and synthesized on the basis of, inter alia, the following considerations: 1) platinum complexes with carrier molecules as ligands should prove useful for achieving increasing drug concentration in tumor tissues; 2) platinum complexes with chemotherapeutic agents as ligands could afford polyfunctional drugs with synergistic action; 3) complexes containing more than one platinum atom might be more effective than complexes containing only one platinum atom; 4) platinum complexes could be used as sensitizers in radiation therapy. In this paper, we shall give a brief account of the “traditional” analogues, and then critically discuss what we believe could be the new trends in the design of cisplatin analogues.     

Rationalization of the Superior Anticancer Activity of Phenanthriplatin: An In-Depth Computational Exploration

In the effort to overcome issues of toxicity and resistance inherent to treatment by the approved platinum anticancer agents, a large number of cisplatin variants continues today to be prepared and tested. One of the applied strategies is to use monofunctional platinum complexes that, unlike traditional bifunctional compounds, are able to form only a single covalent bond with nuclear DNA. Chirality, aquation reaction, interaction with guanine and N-acetyl methionine as well as, intercalation into, binding to and distortion of DNA have been investigated by using both quantum mechanical DFT and molecular dynamics computations aiming at contributing to the elucidation of the molecular mechanism underlying the significantly enhanced spectrum of activity of the monofunctional Pt^II drug phenanthriplatin. Analogous calculations have been performed in parallel for other two less potent monofunctional Pt^II drugs, pyriplatin and enpyriplatin, which show very different cytotoxic effects.     

Metals in Medicine

Not only the 24 or so essential elements , but also nonessential and even radioactive elements have enormous potential for applications in medicine. In the fight against cancer cisplatin, one of the world's best selling anticancer drugs, is being joined by other platinum, titanium, and ruthenium complexes. Gadolinium(III ) complexes can be safely injected as magnetic resonance imaging contrast agents, and ligand design allows targeting of paramagnetic ions as well as radiodiagnostic (e.g. ^99mTc) and radiotherapeutic isotopes (e.g. ¹⁸⁶Re). Manganese superoxide dismutase mimics, vanadium insulin mimics, ruthenium nitric oxide scavengers, lanthanide-based photosensitizers, and metal-targeted organic agents show exciting clinical potential.     

Internalization of Ineffective Platinum Complex in Nanocapsules Renders It Cytotoxic

Anticancer therapy by platinum complexes, based on nanocarrier‐based delivery, may offer a new approach to improve the efficacy and tolerability of the platinum family of anticancer drugs. The original rules for the design of new anticancer platinum drugs were affected by the fact that, although cisplatin (cis‐[PtCl₂(NH₃)₂) was an anticancer drug, its isomer transplatin was not cytotoxic. For the first time, it is demonstrated that simple encapsulation of an inactive platinum compound in phospholipid bilayers transforms it into an efficient cytotoxic agent. Notably, the encapsulation of transplatin makes it possible to overcome the resistance mechanisms operating in cancer cells treated with cisplatin and prevents inactivation of transplatin in the extracellular environment. It is also shown that transplatin delivered to the cells in nanocapsules, in contrast to free (nonencapsulated) complex, forms cytotoxic cross‐links on DNA.     

Combining aspects of the platinum anticancer drugs picoplatin and BBR3464 to synthesize a new family of sterically hindered dinuclear complexes; their synthesis, binding kinetics and cytotoxicity

Picoplatin is a sterically hindered mononuclear platinum drug undergoing clinical trials. The 2-methylpyridine ring provides steric hindrance to the drug, preventing attack from biological nucleophiles. BBR3464 is a trinuclear platinum drug which was recently in Phase II clinical trials, and is highly cytotoxic both in vitro and in vivo; it derives this activity through the flexible adducts it forms with DNA. In this work we sought to combine the properties of both drugs to synthesise a family of sterically hindered, dinuclear platinum complexes as potential anticancer agents. The bis-pyridyl-based ligands were synthesised through a peptide coupling reaction using diaminoalkanes of differing lengths (n = 2, 4 or 8) and 4-carboxypyridine or 2-methyl-4-carboxypyridine. The resultant dinuclear platinum complexes were synthesised by reacting two equivalents of transplatin or mono-aquated transplatin to each ligand, followed by purification by precipitation with acetone. The unprotected complexes react faster with 5'-guanosine monophosphate (drug to nucleotide ratio 1?:?2; t(1/2) = 2 h), glutathione (1?:?10, t(1/2) = 55 min) and human serum albumin (HSA) (1?:?1, t(1/2) = 24 h) compared to their hindered, protected equivalents (5'-guanosine monophosphate, t(1/2) = 3.5 h; glutathione = 1.7 h; HSA, t(1/2) = 110 h). The complexes were tested for in vitro cytotoxicity in the A2780 and A2780/cp70 ovarian cancer cell line. The unprotected platinum complexes were more cytotoxic than their protected derivatives, but none of the complexes were able to overcome resistance. The results provide important proof-of-concept for the development of a larger family of sterically hindered multinuclear-based platinum complexes.     

Palladium complexes: new candidates for anti-cancer drugs

Platinum complexes which are most studied metal complexes due to their importance as adjuvant therapy of cancers aiming to induce tumor-cell-death. Some of the platinum-based antitumor drugs like cisplatin, carboplatin and oxaliplatin, have several disadvantages including side effects, cisplatin-resistant tumors, limited solubility in aqueous media, and so on. Thus, to achieve lower undesirable toxicity, enhanced solubility, and tumor selectivity, significant amount of work have been devoted to the preparation of modified platinum complexes. One of the ways to design the new anti-tumor agents related to cisplatin is to change the nature of central metal ion. Among the non-platinum metal complexes studied for cancer treatment, palladium(II) derivatives were readily chosen due to their structural analogy with those containing Pt(II) complexes. This review focuses on anti-tumor property of Pd(II) complexes and makes comparisons with similar property of cisplatin. Then, in the review, palladium(II) complexes have been classified according to their leaving ligands into palladium(II) complexes. In the last part, the most important factors affecting on the anti-tumor activity of the Pd(II) complexes were discussed. These factors are encouraging more researches in this field, for future applications.     

基于天然产物的铂类和芳基金属抗癌药物研究进展

临床使用的现代药物超过50%都来自于天然产物,它们不仅能够通过阻止细胞周期进程、抑制癌细胞存活信号通路以及调节免疫细胞等多种生物途径来阻止肿瘤生长及其进程,而且对正常组织表现出较低的毒性。虽然以顺铂为代表的金属抗肿瘤药物广泛用于临床,但是它们存在严重的耐药性和毒副作用,包括肾毒性、神经毒性等。因此,利用天然产物中的优势来改造铂类配合物,有望开发出新型铂类抗癌药物以克服铂药的缺陷。另一方面,芳基金属配合物因其良好的水溶性和对正常组织的低毒性受到了广泛关注,将天然产物与芳基金属配合物相结合,也为开发高效低毒的新型抗癌药物提供了更多可能。结合天然产物和金属各自优势开发基于天然产物的金属配合物作为抗癌剂已成为研究热点,开辟了抗癌的新途径。本文对已经报道的有关天然产物的铂类和芳基金属配合物的研究及作用机理进行了较为全面的综述,并对该领域的未来发展进行了展望。     

Platinum(II)–Gadolinium(III) Complexes as Potential Single‐Molecular Theranostic Agents for Cancer Treatment

Theranostic agents are emerging multifunctional molecules capable of simultaneous therapy and diagnosis of diseases. We found that platinum(II)–gadolinium(III) complexes with the formula [{Pt(NH₃)₂Cl}₂GdL](NO₃)₂ possess such properties. The Gd center is stable in solution and the cytoplasm, whereas the Pt centers undergo ligand substitution in cancer cells. The Pt units interact with DNA and significantly promote the cellular uptake of Gd complexes. The cytotoxicity of the Pt–Gd complexes is comparable to that of cisplatin at high concentrations (≥0.1 mM ), and their proton relaxivity is higher than that of the commercial magnetic resonance imaging (MRI) contrast agent Gd–DTPA. T₁‐weighted MRI on B6 mice demonstrated that these complexes can reveal the accumulation of platinum drugs in vivo. Their cytotoxicity and imaging capabilities make the Pt–Gd complexes promising theranostic agents for cancer treatment.     

Imine‐N‐Heterocyclic Carbenes as Versatile Ligands in Ruthenium(II) p‐Cymene Anticancer Complexes: A Structure–Activity Relationship Study

A family of novel imine‐N‐heterocyclic carbene ruthenium(II) complexes of the general formula [(η⁶‐p‐cymene)Ru(C^N)Cl]PF₆⁻ (where C^N is an imine‐N‐heterocyclic carbene chelating ligand with varying substituents) have been prepared and characterized. In this imine‐N‐heterocyclic carbene chelating ligand framework, there are three potential sites that can be modified, which distinguishes this class of ligand and provides a body of flexibilities and opportunities to tune the cytotoxicity of these ruthenium(II) complexes. The influence of substituent effects of three tunable domains on the anticancer activity and catalytic ability in converting coenzyme NADH to NAD⁺ is investigated. This family of complexes displays an exceedingly distinct anticancer activity against A549 cancer cells, despite their close structural similarity. Complex 9 shows the highest anticancer activity in this series against A549 cancer cells (IC₅₀=14.36 μm ), with an approximately 1.5‐fold better activity than the clinical platinum drug cisplatin (IC₅₀=21.30 μm ) in A549 cancer cells. Mechanistic studies reveal that complex 9 mediates cell death mainly through cell stress, including cell cycle arrest, inducing apoptosis, increasing intracellular reactive oxygen species (ROS) levels, and depolarization of the mitochondrial membrane potential (MMP). Furthermore, lysosomal damage is also detected by confocal microscopy.     

Platinum(II) complexes of reduced amino acid ester Schiff bases: synthesis, characterization, and antitumor activity

A series of platinum(II) complexes of reduced amino acid esters Schiff bases were synthesized as potential anticancer agents and characterized by ¹H NMR, EA, IR, and molar conductivity. These compounds were tested for their DNA interaction with salmon sperm DNA by ultraviolet spectrum and CD spectrum, and their in vitro anticancer activities have been validated against HL-60, KB, BGC-823, and Bel-7402 cell lines by MTT assay. The cytotoxicity of complexes 5d and 5f are better than cisplatin against Bel-7402 cell lines, and show a close cytotoxic effect against HL-60 cell line.     

Insertion of (Bioactive) Equatorial Ligands into Platinum(IV) Complexes

Platinum(IV) prodrugs are highly interesting alternatives to platinum(II) anticancer therapeutics due to their increased tumor selectivity and reduced side effects. In contrast to the established theory, we recently observed that the equatorial ligand(s) of e.g. oxaliplatin(IV) complexes can be hydrolyzed with formation of [(DACH)Pt(OH_eq)₂(OAc_ax)₂]. In the work presented here, we investigated the reactivity and synthetic usability of this complex to be exploited as a precursor for the development of novel platinum(IV) complexes, not able to be synthesized by conventional protocols. Indeed, we could substitute the equatorial hydroxido ligand(s) e.g. by one or two monodentate biotin ligands (which would be oxidized under standard methods). The formed complexes turned out to be very stable with slow ligand release after reduction, ideal for long-circulating tumor-targeting strategies. Therefore, two platinum(IV) complexes with equatorial maleimides, capable of exploiting serum albumin as a natural nanocarrier, were synthesized as well. The complexes showed massively prolonged plasma half-life and distinctly improved anticancer activity in vivo compared to oxaliplatin. Taken together, the newly developed synthetic platform allows the simple and specific insertion of equatorial ligands into platinum(IV) complexes. This will enable the attachment of three different (bioactive) moieties generating targeted triple-action platinum(IV) prodrugs within one single platinum complex.     

钌宝宝的自荐信——我是抗癌小战士

Using the anthropomorphic approach, this article introduces the discovery history of ruthenium elements in the first person role, and focuses on the ruthenium complexes as important therapeutic agents for cancer treatment. We have focused our attention on KP1019 incorporating ruthenium ions complexes which have been already used in clinical or have been advanced to clinical trials as anticancer agents. Moreover, the half-sandwich ruthenium and ruthenium polypyridine complexes drugs are also reviewed.     

Synthesis and cytotoxicity of dinuclear platinum(Ⅱ) complexes of (1S, 3S)-1, 2, 3, 4-tetrahydroisoquinolines

A series of novel dinuclear platinum(Ⅱ) complexes with (1S, 3S)-1,2,3,4-tetrahydroisoquinolines as the ligands were synthesized as potential anticancer agents in several steps starting from commercially available L-DOPA. The cytotoxicities of the series of dinuclear platinum(Ⅱ) complexes of tetrahydroisoquinoline were tested against HCT-8, BEL-7402, A2780, MCF-7, Hela, A549 and BGC-823 cell lines by the MTT test. These complexes showed selective inhibition activity against cisplatin-insensitive cell line Skov3.