Current medicinal chemistry. Anti-cancer agents最新文献

The phosphatidylinositol 3-kinase (PI3K)/Akt (protein kinase B, PKB) signaling pathway plays a critical role in cell growth and survival. Dysregulation of this pathway has been found in a variety of cancer cells. Recently, constitutively active PI3K/Akt signaling has been firmly established as a major determinant for cell growth and survival in an array of cancers. Blocking the constitutively active PI3K/AKT signaling pathway provides a new strategy for targeted cancer therapy. Thus, inhibitors of this signaling pathway would be potential anticancer agents, particularly for cancer cells whose survival and growth are dominated by constitutively active PI3K/Akt signaling. This review describes the current understanding of small molecule drugs targeting this pathway both in vitro and in vivo. Inhibitors and functions of the upstream and downstream molecular targets of the PI3K/Akt pathway are discussed in the context of using the inhibitors to block this pathway for targeted cancer therapy. Special emphasis is placed on the following targets: receptor tyrosine kinases, PI3K, Akt, and the mammalian target of rapamycin. While the molecular therapeutic strategy holds great promise for the treatment of a variety of cancers, few small molecule inhibitors with potential high therapeutic indexes are available. Thus, new inhibitors with high selectivity, bioavailability, and potency are greatly needed. Novel approaches toward the development of PI3K/Akt pathway inhibitors as anticancer therapeutics are discussed in detail, with emphasis on chemical genetics-based and structure-based drug design.

It was found that a class of sulfolipids known as sulfo-quinovosyl-acyl-glycerols (SQAGs) from ferns and algae are potent inhibitors of eukaryotic DNA polymerase alpha and beta and effective anti-neoplastic agents. In developing a procedure for the chemical synthesis of sulfolipids, many derivatives and stereoisomers of SQAGs have been obtained including sulfo-quinovosyl-monoacyl-glycerols (SQMGs) and sulfo-quinovosyl-diacyl-glycerols (SQDGs). This review describes studies on the structure-function relationship between synthetic SQAGs and DNA polymerase alpha and beta, and the relationship to cytotoxic activity. The major action was probably dependent on the fatty acid effect, which was reported previously, although each of the SQAGs was a much stronger inhibitor than just the fatty acid present in the SQAGs. The inhibitory effect could be influenced by the chain size of fatty acids in the SQAGs. The sulfonyl group in quinovose was also needed to inhibit the enzymes. Lineweaver-Burk plots of SQAGs indicated that DNA polymerase alpha was non-competitively inhibited, but the SQAGs were effective as antagonists of both the template-primer DNA-binding and the nucleotide substrate-binding of DNA polymerase beta. Based on these results, the molecular actions of SQAGs and drug design strategies for developing new anti-neoplastic agents were discussed.

The role of selenium in the prevention of cancer has been recently established by laboratory experiments, clinical trials, and epidemiological data. Most of the effects are related to the function of selenium in antioxidant enzyme systems. Animal data, epidemiological data, and intervention trials have shown a clear role for selenium derivatives in both prevention of specific cancers and antitumorigenic effects in postinitiation phases of cancer. Consequently, selenium supplementation has moved from the realm of correcting nutritional deficiencies to one of pharmacological intervention, especially in the clinical domain of cancer chemoprevention. Accordingly, there has been substantial interest directed toward the synthesis of selenium-containing derivatives in recent years that could be used as cancer chemopreventive agents. The current review aims to outline recent developments in the application of selenium derivatives as cancer preventive agents.

Prostate cancer is the most common cancer amongst men in the USA and the second most common malignant cause of male death worldwide after lung cancer. The life time risk of having microscopic evidence of prostate cancer for a 50 year old man is 42%. Prostate cancer is thus becoming an increasingly significant global health problem in terms of mortality, morbidity, as well as economically. This review, discusses current medical therapeutic options for prostate cancer including traditional treatments using luteinising hormone releasing analogues (LHRH), anti-androgens and estrogen treatments, and the use of novel drugs directed against molecular targets considered important in oncogenesis and metastasis. Prostate cancer chemoprevention using 5alpha-reductase inhibitors and the role of gene therapy are also considered.

The application of inorganic chemistry to medicine is a rapidly developing field, and novel therapeutic and diagnostic metals and metal complexes are now having an impact on medical practice. Advances in biocoordination chemistry are crucial for improving the design of compounds to reduce toxic side effects and understand their mechanisms of action. A lot of metal-based drugs are widely used in the treatment of cancer. The clinical success of cisplatin and other platinum complexes is limited by significant side effects acquired or intrinsic resistance. Therefore, much attention has focused on designing new coordination compounds with improved pharmacological properties and a broader range of antitumor activity. Strategies for developing new anticancer agents include the incorporation of carrier groups that can target tumor cells with high specificity. Also of interest is to develop complexes that bind to DNA in a fundamentally different manner than cisplatin, in an attempt to overcome the resistance pathways that have evolved to eliminate the drug. This review focuses on recent advances in developing lanthanide anticancer agents with an emphasis on lanthanide coordination complexes. These complexes may provide a broader spectrum of antitumor activity. They were compared with classical platinum anticancer drugs. Lanthanides are also of interest because of their therapeutic radioisotopes. The dominant pharmacological applications of lanthanides are as agents in radioimmunotherapy and photodynamic therapy.

Dietary chemoprevention has emerged as a cost effective approach to control most prevalent chronic diseases including cancer. In particular, tomato and tomato products are recognised to confer a wide range of health benefits. Epidemiological studies have provided evidence that high consumption of tomatoes effectively lowers the risk of reactive oxygen species (ROS)-mediated diseases such as cardiovascular disease and cancer by improving the antioxidant capacity. Tomatoes are rich sources of lycopene, an antioxidant carotenoid reported to be a more stable and potent singlet oxygen quenching agent compared to other carotenoids. In addition to its antioxidant properties, lycopene shows an array of biological effects including cardioprotective, anti-inflammatory, antimutagenic and anticarcinogenic activities. The anticancer activity of lycopene has been demonstrated both in in vitro and in vivo tumour models. The mechanisms underlying the inhibitory effects of lycopene on carcinogenesis could involve ROS scavenging, upregulation of detoxification systems, interference with cell proliferation, induction of gap-junctional communication, inhibition of cell cycle progression and modulation of signal transduction pathways. This review outlines the sources, structure, absorption, metabolism, bioavailability and pharmacological properties of lycopene with special reference to its antioxidant and anticarcinogenic effects.

Recent investigations on the G-quadruplex motif propose a new strategy for the making of antitumour drugs. Quadruplex-drug complexes have been suggested to inhibit telomerase activity; further, aptamers based on the quadruplex motif have been proved useful as tools aimed at binding and inhibiting particular proteins, thus serving as pharmaceutically active agents. However, the design of new aptamers is difficult because many factors affecting their activity and stability have not still been clarified. The knowledge of the energetics of quadruplex formation is a crucial point in view of their potential therapeutic utilization both as targets as well as therapeutic agents. In this review the energetic aspects of both quadruplex assembly and quadruplex-ligand interactions are discussed together with a summary of recent studies on physico-chemical properties in solution of quadruplex structures obtained from synthetic aptamers, including PNA-DNA chimeras.

Histone deacetylases (HDACs) and histone acetyltransferases (HATs) are enzymes that catalyze the deacetylation and acetylation of lysine residues located in the NH(2) terminal tails of histones and non-histone proteins. Perturbation of this balance is often observed in human cancers and inhibition of HDACs has emerged as a novel therapeutic strategy against cancer. To date, more that 30 groups, academic and industrial, are involved in research related to these target enzymes. Over the past year, dozens of research papers and patent applications describing new HDAC inhibitors belonging to different structural classes have been disclosed. The present review highlights the latest developments in design and synthesis of HDAC inhibitors -- potential anti-cancer drugs.

Despite recent advances in our understanding of the biological processes leading to the development of cancer, there is still a need for new and effective agents to help bring this disease under control. One of the oldest and most effective strategies for developing new chemotherapeutics is the isolation and evaluation of chemicals of natural origin. The importance of natural products for drug discovery has been impressive: One has to only look at the number of clinically active drugs that are used in cancer therapy to see how many are either natural products or are based on natural products. It is also apparent that materials from natural sources are excellent probes (indicators) for cellular targets that, when modulated, may have a deleterious effect upon the survival or proliferation of tumor cells. And the search goes on. Sesquiterpenes are a class of naturally occurring molecules that have demonstrated therapeutic potential in decreasing the progression of cancer. These molecules are 15-carbon isoprenoid compounds that are typically found in plants and marine life. Although this class of compounds has frequently provided encouraging leads for chemotherapeutics, they have not been evaluated as potential anticancer agents. In this review, we provide a current overview of sesquiterpenoids that have potential as anticancer agents.

Pyrylium-type salts derived from DMXAA and FAA are proposed to play an important mechanistic role in anticancer action. Electron transfer (ET) processes apparently initiate cell signaling cascades that lead to the observed effects, such as, antivascular influences, cytokine induction, and apoptosis. Possible participation of nitric oxide and serotonin is discussed. Structure-activity relationships involving DMXAA, FAA, acridines, and quinolines support the hypothetical framework, as well as electrochemistry and photochemistry. Similarity is pointed out to the action of plant hormones, e.g. ethylene. Involvement of ET pathways places the cationic salts within the general mechanistic framework for other anticancer agents. Other drug activities of xanthenones are in accord with the ET approach. Insight into fundamental mechanistic aspects should aid in development of improved drugs in this class through rational design.