超分子抗癌药物双环铂的结构研究

铂类抗癌药物在水中的溶解度和稳定性直接与药物的活性和毒性有关.几十年来,为了改进药物的效能和降低药物的毒性,做了大量的研究.超分子铂类化合物可能具有与众不同的物理化学性质,我们成功设计和合成了一个新型的超分子抗癌药物-双环铂,己证实双环铂对人类的恶性肿瘤有好的治疗效果.用X射线单晶衍射法测定了双环铂的晶体结构,又用电喷雾离子化质谱研究了它在水溶液中的状态.根据实验结果提出了双环铂在水溶液中的结构模型,解释了双环铂在水中好的稳定性和溶解度.     

Structural studies of dicycloplatin, an antitumor supramolecule

The solubility and stability of platinum-based anticancer agents have a direct bearing on their activity and toxicity. Much research has been conducted over the past decades in order to prepare drugs such as cisplatin and carboplatin with improved efficacy and reduced toxicity. Based on the premise that supramolecular platinum agents may have superior physicochemical properties, we successfully designed a novel anticancer agent, dicycloplatin, which has proven to be active against a number of human malignancies. The crystal structure of dicycloplatin has been determined. An aqueous solution of dicycloplatin was also studied using electrospray ionization mass spectrometry (ESI-MS). Based on the experimental observations, a model of the structure in aqueous solution is proposed which explains both the higher solubility and higher stability of dicycloplatin compared with carboplatin.     

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.     

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.     

Potent Anticancer Activity and Possible Low Toxicity of Platinum(II) Complexes with Functionalized 1,1‐Cyclobutanedicarboxylate as a Leaving Ligand

Two platinum(II) complexes, DN603 and DN604, were designed and prepared by using 3‐oxocyclobutane‐1,1‐dicarboxylate as a ligand. The compounds were prepared according to the concept that incorporation of a functionalized moiety in the leaving ligand that did not affect its coordination bonding to the metal atom would play a key role in the anticancer activity of the resulting platinum complex. The newly prepared compounds were found to show potent in vitro anticancer activity comparable to cisplatin and oxaliplatin; especially DN604, which exhibited low acute toxicity similar to carboplatin, and presented acceptable solubility and stability in water. Chemical and biological results indicated that the functionalized moiety, uncoordinated, led to potent anticancer activity and low apparent toxicity of the platinum complexes by affecting the kinetic properties of the compounds.     

抗肿瘤多核铂配合物的研究

多核铂配合物作为非经典铂抗肿瘤药物,其抗肿瘤机制与现有铂类抗肿瘤药物不同,因而在克服现有铂类抗肿瘤药物耐药性方面有着巨大的潜力。本文综述了多核铂类抗肿瘤药物的研究进展,以连接铂原子的桥配体结构的不同,可分为六大类:以烷基二胺及其衍生物为桥的多核铂配合物、以含氮杂环为桥的多核铂配合物、以羧酸根为桥的多核铂配合物、以卤素离子为桥的多核铂配合物、以含硫配体为桥的多核铂配合物及以其他配体为桥的多核铂配合物。本文还介绍了这几类多核铂配合物的抗肿瘤机理及在克服顺铂耐药性机理方面的研究进展。     

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。     

A Triangular Platinum(II) Multinuclear Complex with Cytotoxicity Towards Breast Cancer Stem Cells

The preparation of multinuclear metal complexes offers a route to novel anticancer agents and delivery systems. The potency of a novel triangular multinuclear complex containing three platinum atoms, Pt‐3 , towards breast cancer stem cells (CSCs) is reported. The trinuclear platinum(II) complex, Pt‐3 exhibits selective toxicity towards breast CSCs over bulk breast cancer cells and non‐tumorigenic breast cells. Remarkably, Pt‐3 inhibits the formation, size, and viability of mammospheres to a better extent than salinomycin, an established CSC‐potent agent, and cisplatin and carboplatin, clinically used platinum drugs. Mechanism of action studies show that Pt‐3 effectively enters breast CSCs, penetrates the nucleus, induces genomic DNA damage, and prompts caspase‐dependent apoptosis. To the best of our knowledge, Pt‐3 is the first multinuclear platinum complex to selectively kill breast CSCs over other breast cell types.     

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。     

Sensitive inductively coupled plasma mass spectrometry assay for the determination of platinum originating from cisplatin, carboplatin, and oxaliplatin in human plasma ultrafiltrate

We present a highly sensitive, rapid method for the determination of platinum originating from the anticancer agents cisplatin, carboplatin, and oxaliplatin in human plasma ultrafiltrate. The method is based on the quantification of platinum by inductively coupled plasma mass spectrometry and allows quantification of 7.50 ng l-1 platinum in only 150 microl of matrix. Sample pretreatment involves dilution of samples with 1% HNO3. Validation fulfilled the most recent FDA guidelines for bioanalytical method validation. Validated ranges of quantification were 7.50 ng l-1 to 1.00x10(5) ng l-1 in plasma ultrafiltrate for all three platinum compounds. The assay is now successfully used to support pharmacokinetic studies in cancer patients treated with cisplatin, carboplatin, or oxaliplatin.     

EXAFS and IR structural study of platinum-based anticancer drugs' degradation by diethyl dithiocarbamate

Platinum compounds constitute a discrete class of DNA-damaging anticancer drug agents, including cisplatin, carboplatin, and oxaliplatin. The toxicity of such drugs raises the problem of waste detoxification. Diethyl dithiocarbamate (DDTC) is recommended by the World Heath Organization (WHO) for the destruction of cisplatin, but the degradation product has not been structurally characterized. This paper deals with the extended X-ray absorption fine structure (EXAFS) and IR structural study of the reaction products of DDTC with cisplatin, carboplatin, and oxaliplatin. Cisplatin and carboplatin give the same reaction product: Pt(DDTC)2. In the case of oxaliplatin, we observed the formation of [(diaminocyclohexane)(DDTC)Pt(II)]. In all cases, the replacement of labile ligands by strong ligands should lead to inactive compounds. Our results suggest that the WHO inactivation protocol might be extended to carboplatin and oxaliplatin. Nevertheless, this should be validated by toxicity tests of the degradation products.     

Advances in Platinum Chemotherapeutics

The approved platinum(II)‐based anticancer agents cisplatin, carboplatin and oxaliplatin are widely utilised in the clinic, although with numerous disadvantages. With the aim of circumventing unwanted side‐effects, a great deal of research is being conducted in the areas of cancer‐specific targeting, drug administration and drug delivery. The targeting of platinum complexes to cancerous tissues can be achieved by the attachment of small molecules with biological significance. In addition, the administration of platinum complexes in the form of platinum(IV) allows for intracellular reduction to release the active form of the drug, cisplatin. Drug delivery includes such technologies as liposomes, dendrimers, polymers and nanotubes, with all showing promise for the delivery of platinum compounds. In this paper we highlight some of the recent advances in the field of platinum chemotherapeutics, with a focus on the technologies that attempt to utilise the cytotoxic nature of cisplatin, whilst improving drug targeting to reduce side‐effects.     

Metallkomplexe als Antikrebsmittel

The platinum complex cisplatin is in worldwide use since 1978 as anticancer agent. Disadvantages of the cisplatin therapy are both drug resistance and severe side effects. To avoid these drawbacks several strategies have been developed in tumor research. Patients treated with second‐generation platinum complexes experience already less severe side effects. Organometallic and coordination complexes with different metals can be used to target DNA as well as overexpressed proteins and enzymes in cancer cells. In contrast, delivery systems for anticancer drugs target cancer cells, while being selectively accumulated in tumor tissue.     

Design of Enzymatically Cleavable Prodrugs of a Potent Platinum‐Containing Anticancer Agent

Using a versatile synthetic approach, a new class of potential ester prodrugs of highly potent, but systemically too toxic, platinum–acridine anticancer agents was generated. The new hybrids contain a hydroxyl group, which has been masked with a cleavable lipophilic acyl moiety. Both butanoic (butyric) and bulkier 2‐propanepentanoic (valproic) esters were introduced. The goals of this design were to improve the drug‐like properties (e.g., logD) and to reduce the systemic toxicity of the pharmacophore. Two distinct pathways by which the target compounds undergo effective ester hydrolysis, the proposed activating step, have been confirmed: platinum‐assisted, self‐immolative ester cleavage in a low‐chloride environment (LC‐ESMS, NMR spectroscopy) and enzymatic cleavage by human carboxylesterase‐2 (hCES‐2) (LC‐ESMS). The valproic acid ester derivatives are the first example of a metal‐containing agent cleavable by the prodrug‐converting enzyme. They show excellent chemical stability and reduced systemic toxicity. Preliminary results from screening in lung adenocarcinoma cell lines (A549, NCI‐H1435) suggest that the mechanism of the valproic esters may involve intracellular deesterification.     

符合经典构效关系的抗肿瘤铂类药物

综述了自顺铂、卡铂后符合经典构效关系的铂类抗肿瘤药物的发展概况，按载体配基和离去基团的结构特征进行了分类，总结了各类配合物的构效关系和临床进展，其中重点对手性二胺配体的铂(Ⅱ)配合物进行了介绍。并讨论了顺铂、卡铂、奥沙利铂的作用机理。     

The Power of Kinetic Inertness in Improving Platinum Anticancer Therapy by Circumventing Resistance and Ameliorating Nephrotoxicity

Even in the modern era of precision medicine and immunotherapy, chemotherapy with platinum (Pt) drugs remains among the most commonly prescribed medications against a variety of cancers. Unfortunately, the broad applicability of these blockbuster Pt drugs is severely limited by intrinsic and/or acquired resistance, and high systemic toxicity. Considering the strong interconnection between kinetic lability and undesired shortcomings of clinical Pt drugs, we rationally designed kinetically inert organometallic Pt based anticancer agents with a novel mechanism of action. Using a combination of in vitro and in vivo assays, we demonstrated that the development of a remarkably efficacious but kinetically inert Pt anticancer agent is feasible. Along with exerting promising antitumor efficacy in Pt-sensitive as well as Pt-resistant tumors in vivo, our best candidate has the ability to mitigate the nephrotoxicity issue associated with cisplatin. In addition to demonstrating, for the first time, the power of kinetic inertness in improving the therapeutic benefits of Pt based anticancer therapy, we describe the detailed mechanism of action of our best kinetically inert antitumor agent. This study will certainly pave the way for designing the next generation of anticancer drugs for effective treatment of various cancers.     

Toxicity and Anticancer Potential of Karwinskia: A Review

Karwinskia genus consists of shrubs and small trees. Four toxic compounds have been isolated from Karwinskia plants, which were typified as dimeric anthracenones and named T496, T514, T516, and T544. Moreover, several related compounds have been isolated and characterized. Here we review the toxicity of the fruit of Karwinskia plants when ingested (accidentally or experimentally), as well as the toxicity of its isolated compounds. Additionally, we analyze the probable antineoplastic effect of T514. Toxins cause damage mainly to nervous system, liver, lung, and kidney. The pathophysiological mechanism has not been fully understood but includes metabolic and structural alterations that can lead cells to apoptosis or necrosis. T514 has shown selective toxicity in vitro against human cancer cells. T514 causes selective and irreversible damage to peroxisomes; for this reason, it was renamed peroxisomicine A1 (PA1). Since a significant number of malignant cell types contain fewer peroxisomes than normal cells, tumor cells would be more easily destroyed by PA1 than healthy cells. Inhibition of topoisomerase II has also been suggested to play a role in the effect of PA1 on malignant cells. More research is needed, but the evidence obtained so far indicates that PA1 could be an effective anticancer agent.     

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.     

Anticancer Potencies of PtII‐ and PdII‐linked M2L4 Coordination Capsules with Improved Selectivity

Pt^II‐ and Pd^II‐linked M₂L₄ coordination capsules, providing a confined cavity encircled by polyaromatic frameworks, exhibit anticancer activities superior to cisplatin against two types of leukemic cells (HL‐60 and SKW‐3) and pronounced toxicity against cisplatin‐resistant cells (HL‐60/CDDP). Notably, the cytotoxic selectivities of the Pt^II and Pd^II capsules toward cancerous cells are up to 5.3‐fold higher than that of cisplatin, as estimated through the non‐malignant/malignant‐cells toxicity ratio employing normal kidney cells (HEK‐293). In addition, the anticancer activity of the coordination capsules can be easily altered upon encapsulation of organic guest molecules.