Synthesis of a glucose conjugate of pristimerin and evaluation of its anticancer activity

Taking advantage of the Warburg effect in cancer cells, glucose conjugation has emerged as a useful strategy for targeted delivery of anticancer agents. Pristimerin is a naturally occurring triterpenoid that displays potent but non-selective cytotoxicity. We developed a convergent and modular approach to construction of glucose?payload conjugates featuring copper-mediated azide?alkyne cycloaddition and prepared a glucose conjugate of pristimerin through this approach. The anticancer activity of this conjugate was evaluated in cancer cells and normal cells; however, the selectivity toward cancer cells was not significantly improved. We then examined the extracellular stability of the conjugate and found that its ester linkage was cleaved rapidly in Dulbecco's Modified Eagle's Medium at 37 °C, which resulted in the release of pristimerin. In fact, the inorganic components in this medium were sufficient to induce the cleavage. Given that the subtle difference between intrinsic stability and extracellular stability of the conjugate linker is often underappreciated, this work highlights the importance of the latter in the development of target-selective conjugates.     

Hydrogen peroxide inducible DNA cross-linking agents: targeted anticancer prodrugs

The major concern for anticancer chemotherapeutic agents is the host toxicity. The development of anticancer prodrugs targeting the unique biochemical alterations in cancer cells is an attractive approach to achieve therapeutic activity and selectivity. We designed and synthesized a new type of nitrogen mustard prodrug that can be activated by high level of reactive oxygen species (ROS) found in cancer cells to release the active chemotherapy agent. The activation mechanism was determined by NMR analysis. The activity and selectivity of these prodrugs toward ROS was determined by measuring DNA interstrand cross-links and/or DNA alkylations. These compounds showed 60-90% inhibition toward various cancer cells, while normal lymphocytes were not affected. To the best of our knowledge, this is the first example of H(2)O(2)-activated anticancer prodrugs.     

QSAR and Molecular Docking Studies of Pyrimidine-Coumarin-Triazole Conjugates as Prospective Anti-Breast Cancer Agents

Cancer is a life-threatening disease and is the second leading cause of death worldwide. Although many drugs are available for the treatment of cancer, survival outcomes are very low. Hence, rapid development of newer anticancer agents is a prime focus of the medicinal chemistry community. Since the recent past, computational methods have been extensively employed for accelerating the drug discovery process. In view of this, in the present study we performed 2D-QSAR (Quantitative Structure-Activity Relationship) analysis of a series of compounds reported with potential anticancer activity against breast cancer cell line MCF7 using QSARINS software. The best four models exhibited a r² value of 0.99. From the generated QSAR equations, a series of pyrimidine-coumarin-triazole conjugates were designed and their MCF7 cell inhibitory activities were predicted using the QSAR equations. Furthermore, molecular docking studies were carried out for the designed compounds using AutoDock Vina against dihydrofolate reductase (DHFR), colchicine and vinblastine binding sites of tubulin, the key enzyme targets in breast cancer. The most active compounds identified through these computational studies will be useful for synthesizing and testing them as prospective novel anti-breast cancer agents.     

稀土氨基酸配合物与核酸的相互作用*

很多抗癌金属药物是以核酸为靶标。阐明小分子与核酸之间的相互作用对筛选具有高效选择性和低毒副作用的抗癌药物有重要意义。近年来,开发新型的具有对核酸序列特异性识别能力的抗癌药物己成为本领域的研究热点。稀土离子具有良好的磁学、光学、电学特性和配位能力,使稀土配合物成为新型药物试剂。然而,稀土离子在中性条件下易水解的特性极大地阻碍了稀土配合物对核酸分子识别的研究。近年来在近生理条件下合成的一系列镧系氨基酸配合物具有结构稳定、溶解性好等优点,解决了镧系离子易水解的问题。本文总结了目前关于镧系氨基酸配合物与核酸的相互作用及其序列选择性等方面的研究进展。     

Porphyrin-bile acid conjugates: from saccharide recognition in the solution to the selective cancer cell fluorescence detection

This paper describes the preparation and use of conjugates of porphyrins and bile acids as ligands to bind to tumor expressed saccharides. Bile acid-porphyrin conjugates were tested for recognition of saccharides that are typically present on malignant tumor cells. Fluorescence microscopy, in vitro PDT cell killing, and PDT of subcutaneous 4T1 mouse tumors is reported. High selectivity for saccharide cancer markers and cancer cells was observed. This in vivo and in vitro study demonstrated high potential use for these compounds in targeted photodynamic therapy.     

Evaluation of inhibitory effects of benzothiazole and 3-amino-benzothiazolium derivatives on DNA topoisomerase II by molecular modeling studies

There has been considerable interest in DNA topoisomerases over the last decade, as they have been shown to be one of the major cellular targets in anticancer drug development. Previously we synthesized some benzothiazole derivatives and corresponding benzothiazolium forms, and tested their DNA inhibitory activity to develop novel antitumor agents. Among the 12 prepared compounds, compound BM3 (3-aminobenzothiazole-3-ium 4-methylbenzene sulfonate) exhibited extreme topoisomerase II inhibitory activity compared with the reference drug etoposide. We also tried to determine the DNA and enzyme binding abilities of BM3 and found that BM3 acted on topoisomerase II first at low doses, while it had also showed DNA minor groove binding properties at higher doses. In this study the interactions between DNA topoisomerase II and the compounds were examined in detail by molecular modelling studies such as molecular docking and pharmacophore analysis performed using Discovery Studio 3.5. As a result, it was found that benzothiazolium compounds exhibited a totally different mechanism than benzothiazoles by binding to the different amino acids at the active site of the protein molecule. 3-Aminobenzothiazoliums are worthy of carrying onto anticancer studies; BM3 especially would be a good anticancer candidate for preclinical studies.     

Anticancer alpha-helical peptides and structure/function relationships underpinning their interactions with tumour cell membranes

Cancer is a major cause of premature death and there is an urgent need for new anticancer agents with novel mechanisms of action. Here we review recent studies on a group of peptides that show much promise in this regard, exemplified by arthropod cecropins and amphibian magainins and aureins. These molecules are alpha-helical defence peptides, which show potent anticancer activity (alpha-ACPs) in addition to their established roles as antimicrobial factors and modulators of innate immune systems. Generally, alpha-ACPs exhibit selectivity for cancer and microbial cells primarily due to their elevated levels of negative membrane surface charge as compared to non-cancerous eukaryotic cells. The anticancer activity of alpha-ACPs normally occurs at micromolar levels but is not accompanied by significant levels of haemolysis or toxicity to other mammalian cells. Structure/function studies have established that architectural features of alpha-ACPs such as amphiphilicty levels and hydrophobic arc size are of major importance to the ability of these peptides to invade cancer cell membranes. In the vast majority of cases the mechanisms underlying such killing involves disruption of mitochondrial membrane integrity and/or that of the plasma membrane of the target tumour cells. Moreover, these mechanisms do not appear to proceed via receptor-mediated routes but are thought to be effected in most cases by the carpet/toroidal pore model and variants. Usually, these membrane interactions lead to loss of membrane integrity and cell death utilising apoptic and necrotic pathways. It is concluded that that alpha-ACPs are major contenders in the search for new anticancer drugs, underlined by the fact that a number of these peptides have been patented in this capacity.     

Synthesis and cytotoxic evaluation of new colchicine derivatives bearing 1, 3, 4-thiadiazole moieties

In search of novel anticancer agents, a series of N-methyl colchiceinamide derivatives (7a-7i) containing 1,3,4-thiadiazole moieties were synthesized, and their structures were confirmed by spectral analysis. Cytotoxicity of these compounds was evaluated by MTT assay in vitro against four human tumor cell lines, i.e. A2780, A549, BEL7402, and MCF-7. The results indicated that most of the derivatives showed significant anticancer activities, particularly, compounds 7h and 7i showed more potent cytotoxic activities of all screened cancer cells than colchicine.     

Synthesis and Biological Evaluation of Amino Chalcone Derivatives as Antiproliferative Agents

Chalcone is a common scaffold found in many biologically active compounds. The chalcone scaffold was also frequently utilized to design novel anticancer agents with potent biological efficacy. Aiming to continue the research of effective chalcone derivatives to treat cancers with potent anticancer activity, fourteen amino chalcone derivatives were designed and synthesized. The antiproliferative activity of amino chalcone derivatives was studied in vitro and 5-Fu as a control group. Some of the compounds showed moderate to good activity against three human cancer cells (MGC-803, HCT-116 and MCF-7 cells) and compound 13e displayed the best antiproliferative activity against MGC-803 cells, HCT-116 cells and MCF-7 cells with IC₅₀ values of 1.52 μM (MGC-803), 1.83 μM (HCT-116) and 2.54 μM (MCF-7), respectively which was more potent than the positive control (5-Fu). Further mechanism studies were explored. The results of cell colony formatting assay suggested compound 10e inhibited the colony formation of MGC-803 cells. DAPI fluorescent staining and flow cytometry assay showed compound 13e induced MGC-803 cells apoptosis. Western blotting experiment indicated compound 13e induced cell apoptosis via the extrinsic/intrinsic apoptosis pathway in MGC-803 cells. Therefore, compound 13e might be a valuable lead compound as antiproliferative agents and amino chalcone derivatives worth further effort to improve amino chalcone derivatives’ potency.     

A New Chalcone Derivative with Promising Antiproliferative and Anti-Invasion Activities in Glioblastoma Cells

Glioblastoma (GBM) is the most common and most deadly primary malignant brain tumor. Current therapies are not effective, the average survival of GBM patients after diagnosis being limited to few months. Therefore, the discovery of new treatments for this highly aggressive brain cancer is urgently needed. Chalcones are synthetic and naturally occurring compounds that have been widely investigated as anticancer agents. In this work, three chalcone derivatives were tested regarding their inhibitory activity and selectivity towards GBM cell lines (human and mouse) and a non-cancerous mouse brain cell line. The chalcone 1 showed the most potent and selective cytotoxic effects in the GBM cell lines, being further investigated regarding its ability to reduce critical hallmark features of GBM and to induce apoptosis and cell cycle arrest. This derivative showed to successfully reduce the invasion and proliferation capacity of tumor cells, both key targets for cancer treatment. Moreover, to overcome potential systemic side effects and its poor water solubility, this compound was encapsulated into liposomes. Therapeutic concentrations were incorporated retaining the potent in vitro growth inhibitory effect of the selected compound. In conclusion, our results demonstrated that this new formulation can be a promising starting point for the discovery of new and more effective drug treatments for GBM.     

Antisense and antigene inhibition of gene expression by cell-permeable oligonucleotide-oligospermine conjugates

Oligonucleotides and their derivatives are a proven chemical strategy for modulating gene expression. However, their negative charge remains a challenge for delivery and target recognition inside cells. Here we show that oligonucleotide-oligospermine conjugates (Zip nucleic acids or ZNAs) can help overcome these shortcomings by serving as effective antisense and antigene agents. Conjugates containing DNA and locked nucleic acid (LNA) oligonucleotides are active, and oligospermine conjugation facilitates carrier-free cell uptake at nanomolar concentrations. Conjugates targeting the CAG triplet repeat within huntingtin (HTT) mRNA selectively inhibit expression of the mutant huntingtin protein. Conjugates targeting the promoter of the progesterone receptor (PR) function as antigene agents to block PR expression. These observations support further investigation of ZNA conjugates as gene silencing agents.     

Novel pyridine and pyrimidine derivatives as promising anticancer agents: A review

Pyridines and pyrimidines are the class of heterocyclic nitrogenous compounds having plethora of applications in anticancer drug development. These synthetic sources serve as the potent class of compounds in treatment of breast cancer, myeloid leukemia, pancreatic cancer, liver cancer and idiopathic respiratory fibrosis etc. The present review enumerates the results of studies published during past three years (2019–2021) on pyridine and pyrimidine analogues with their respective anticancer properties characterized in vitro or through in silico studies and illustrates their potential in development of anticancer agents. Recent advances on pyridine and pyrimidine analogues mentioned in this review add to the appealing opportunities for cancer therapy.     

Synthesis and antitumor evaluation of symmetrical 1,5-diamidoanthraquinone derivatives as compared to their disubstituted homologues

A series of symmetrical 1,5-diamidoanthraquinone derivatives with potentially bioreducible groups has been synthesized and their cytostatic activity against the panel of various cancer cell lines in vitro has been studied. Preliminary structure-activity relationships were established. The results indicated that compounds 5 and 18 exhibited significant potent cytotoxicity at 1.24-1.75 microM for Hepa G2 cell line; compounds 5, 16, and 18 exhibited cytotoxicity at 0.14-1.82 microM for 2.2.15 cell line as determined by XTT colorimetric assay. Two structurally related compounds, mitoxantrone and adriamycin, were tested in parallel as positive controls. In addition, it was found that compounds 5 and 18 were a more potent and specific human hepatoma cell line than mitoxantrone and showed comparable activity to adriamycin. Among them, compound 18 was the most potent for 2.2.15 cells. We have demonstrated that the anthraquinone moiety is essential for activity and that less sterically hindered substituents contribute to enhanced in vitro efficacy. Implications for amidoanthraquinone cytotoxicity as potential anticancer agents are discussed. We further delineate the nature of the pharmacophore for this class of compounds, which provides a rational basis for the structure-activity relationships.     

Luminescent Cyclometalated Platinum(II) Complex Forms Emissive Intercalating Adducts with Double‐Stranded DNA and RNA: Differential Emissions and Anticancer Activities

Luminescent metallo‐intercalators are potent biosensors of nucleic acid structure and anticancer agents targeting DNAs. There are few examples of luminescent metallo‐intercalators which can simultaneously act as emission probes of nucleic acid structure and display promising anticancer activities. Herein, we describe a luminescent platinum(II) complex, [Pt(C^N^N)(C≡NtBu)]ClO₄ ( 1 a , HC^N^N= 6‐phenyl‐2,2′‐bipyridyl), that intercalates between the nucleobases of nucleic acids, accompanied by an increase in emission intensity and/or a significant change in the maximum emission wavelength. The changes in emission properties measured with double‐stranded RNA (dsRNA) are different from those with dsDNA used in the binding reactions. Complex 1 a exhibited potent anticancer activity towards cancer cells in vitro and inhibited tumor growth in a mouse model. The stabilization of the topoisomerase I–DNA complex with resulting DNA damage by 1 a is suggested to contribute to its anticancer activity.     

Generation of free radicals by emodic acid and its [D-Lys6]GnRH-conjugate

In an attempt to develop an efficient chemotherapeutic agent targeted at malignant cells that express receptors to gonadotropin releasing hormone (GnRH) we coupled [D-Lys6]GnRH covalently to an emodin derivative, i.e. emodic acid (Emo) to yield [D-Lys6(Emo)]GnRH. Emodin is a naturally occurring anthraquinone which is widely used as a laxative and has other versatile biological activities. Physico-chemical studies employing electron paramagnetic resonance and electrochemistry of the conjugate as well as the (Emo) moiety showed that these compounds could be easily reduced either chemically, photochemically or enzymatically to their corresponding semiquinones. In the presence of oxygen the semiquinones generated reactive oxygen species (ROS), mainly superoxide and hydroxyl radicals, which were detected by the spin trapping method. Moreover, upon irradiation with visible light these compounds produced ROS and a highly reactive excited triplet state of Emo, which by itself may cause the oxidation of certain electron acceptors such as amino acids and bases of nucleic acids. Thus, [D-Lys6]GnRH-photosensitizer conjugates may be potentially used for targeted photodynamic chemotherapy aimed at treating cancer cells that carry GnRH receptors. These conjugates may also induce cytotoxicity in the dark similar to common conventional chemotherapeutic agents. The peptidic moiety, [D-Lys6]GnRH, was found to be stable toward highly reactive ROS generated either from enzymatic reduction or upon photoirradiation. The physico-chemical properties of Emo were only marginally influenced by the peptidic [D-Lys6]GnRH carrier.     

One-pot synthesis and biological evaluation of novel 4-[3-fluoro-4-(morpholin-4-yl)]phenyl-1H-1,2,3-triazole derivatives as potent antibacterial and anticancer agents

In search of better antibacterial and anticancer agents, a series of novel 4-[3-fluoro-4-(morpholin-4-yl)]phenyl-1H-1,2,3-triazole derivatives were synthesized ( 6a - l and 8a - j ) by using 3-fluoro-4-morpholinoaniline, alkyne, and triflyl azide via an in situ generated 4-(4-azido-2-fluorophenyl)morpholine and evaluated for their antibacterial and anticancer activity in vitro. Antibacterial activity against three G+ bacterial strains and anticancer activity against breast cancer cell line (MCF-7) and cervical carcinoma cell line (HeLa) was evaluated. Among all the tested compounds, 6h , 6i , and 8b exhibited potent antibacterial activity against tested gram-positive bacterial strains. The anticancer activity screening results of 8f , 8h , and 8i exhibited potent cytotoxic activity against two cancer cell lines with IC₅₀ values nearer to the standard drug, doxorubicin. The remaining compounds have shown good to moderate activity against the tested cell lines. On the basis of the results obtained, a structure-activity relationship (SAR) is discussed.     

The Effect of Beta Adrenoreceptor Blockers on Viability and Cell Colony Formation of Non-Small Cell Lung Cancer Cell Lines A549 and H1299

Beta adrenoblockers are a large class of drugs used to treat cardiovascular diseases, migraines, glaucoma and hyperthyroidism. Over the last couple of decades, the anticancer effects of these compounds have been extensively studied. However, the exact mechanism is still not known, and more detailed studies are required. The aim of our study was to evaluate the anticancer activity of beta adrenoblockers in non-small cell lung cancer cell lines A549 and H1299. In order to find the relationship with their selectivity to beta adrenoreceptors, selective (atenolol, betaxolol, esmolol, metoprolol) and non-selective (pindolol, propranolol and timolol) beta blockers were tested. The effect on cell viability was evaluated by MTT assay, and the activity on cell ability to form colonies was tested by clonogenic assay. The type of cell death was evaluated by cell double staining with Hoechst 33342 and Propidium iodide. The most active adrenoblockers against both tested cancer cell lines were propranolol and betaxolol. They completely inhibited lung cancer cell colony formation at 90% of the EC₅₀ (half-maximal effective concentration) value. Most tested compounds induced cell death through apoptosis and necrosis. There was no correlation established between beta adrenoblocker anticancer activity and their selectivity to beta adrenoreceptors.     

Anticancer Activities of Marine-Derived Phenolic Compounds and Their Derivatives

Since the middle of the last century, marine organisms have been identified as producers of chemically and biologically diverse secondary metabolites which have exerted various biological activities including anticancer, anti-inflammatory, antioxidant, antimicrobial, antifouling and others. This review primarily focuses on the marine phenolic compounds and their derivatives with potent anticancer activity, isolated and/or modified in the last decade. Reports on the elucidation of their structures as well as biosynthetic studies and total synthesis are also covered. Presented phenolic compounds inhibited cancer cells proliferation or migration, at sub-micromolar or nanomolar concentrations (lamellarins D (37), M (38), K (39), aspergiolide B (41), fradimycin B (62), makulavamine J (66), mayamycin (69), N-acetyl-N-demethylmayamycin (70) or norhierridin B (75)). In addition, they exhibited anticancer properties by a diverse biological mechanism including induction of apoptosis or inhibition of cell migration and invasive potential. Finally, phlorotannins 1–7 and bromophenols 12–29 represent the most researched phenolic compounds, of which the former are recognized as protective agents against UVB or gamma radiation-induced skin damages. Finally, phenolic metabolites were assorted into six main classes: phlorotannins, bromophenols, flavonoids, coumarins, terpenophenolics, quinones and hydroquinones. The derivatives that could not be attributed to any of the above-mentioned classes were grouped in a separate class named miscellaneous compounds.     

Use of Half-Generation PAMAM Dendrimers (G0.5–G3.5) with Carboxylate End-Groups to Improve the DACHPtCl2 and 5-FU Efficacy as Anticancer Drugs

The DACHPtCl₂ compound (trans-(R,R)-1,2-diaminocyclohexanedichloroplatinum(II)) is a potent anticancer drug with a broad spectrum of activity and is less toxic than oxaliplatin (trans-l-diaminocyclohexane oxalate platinum II), with which it shares the active metal fragment DACHPt. Nevertheless, due to poor water solubility, its use as a chemotherapeutic drug is limited. Here, DACHPtCl₂ was conjugated, in a bidentate form, with half-generation PAMAM dendrimers (G0.5–G3.5) with carboxylate end-groups, and the resulting conjugates were evaluated against various types of cancer cell lines. In this way, we aimed at increasing the solubility and availability at the target site of DACHPt while potentially reducing the adverse side effects. DNA binding assays showed a hyperchromic effect compatible with DNA helix’s disruption upon the interaction of the metallodendrimers and/or the released active metallic fragments with DNA. Furthermore, the prepared DACHPt metallodendrimers presented cytotoxicity in a wide set of cancer cell lines used (the relative potency regarding oxaliplatin was in general high) and were not hemotoxic. Importantly, their selectivity for A2780 and CACO-2 cancer cells with respect to non-cancer cells was particularly high. Subsequently, the anticancer drug 5-FU was loaded in a selected metallodendrimer (the G2.5COO(DACHPt)₁₆) to investigate a possible synergistic effect between the two drugs carried by the same dendrimer scaffold and tested for cytotoxicity in A2780cisR and CACO-2 cancer cell lines. This combination resulted in IC₅₀ values much lower than the IC₅₀ for 5-FU but higher than those found for the metallodendrimers without 5-FU. It seems, thus, that the metallic fragment-induced cytotoxicity dominates over the cytotoxicity of 5-FU in the set of considered cell lines.