Anti-Cancer Agents in Medicinal Chemistry (Formerly Current Medicinal Chemistry - Anti-Cancer Agents) - Volume 17, Issue 14, 2017

Tetrazole cycle is a promising pharmacophore fragment frequently used in the development of novel drugs. This moiety is a stable, practically non-metabolized bioisosteric analog of carboxylic, cis-amide, and other functional groups. Over recent 10–15 years, various isomeric forms of tetrazole (NH-unsubstituted, 1H-1- substituted, and 2H-2-substituted tetrazoles) have been successfully used in the design of promising anticancer drugs. Coordination compounds of transition metals containing tetrazoles as ligands, semisynthetic tetrazolyl derivatives of natural compounds (biogenic acids, peptides, steroids, combretastatin, etc.), 5-oxo and 5- thiotetrazoles, and some other related compounds have been recognized as promising antineoplastic agents. This review presents a comprehensive analysis of modern approaches to synthesis of these tetrazole derivatives as well as their biological (anticancer) properties. The most promising structure types of tetrazoles to be used as anticancer agents have been picked out.

Cancer is a rapidly growing disease of current era which poses a major life threaten situation to human beings. Continuous research is going on in the direction to develop effective molecules for the treatment of the cancer. These efforts include searching of more active heterocyclic compounds possessing potential anticancer activity. The 1,3,4-Oxadiazole scaffold is a five member heterocyclic ring having versatile activities and created interest for synthetic organic and medicinal chemists for the designing of novel compounds having anticancer activity. The important mechanism behind tumor suppression by 1,3,4-Oxadiazole is related with the inhibition of different growth factors, enzymes and kinases etc. The current literature surveys revealed that 1,3,4-Oxadiazole is a promising lead for anti-cancer agents by the inhibition of telomerase activity. In cancerous cells telomerase enzyme is activated which maintains and restores the telomere which leads to cell proliferation. The telomerase inhibitors with enhanced specificity and improved pharmacokinetics have been considered for design and development of novel anti-cancer agents. This review focuses primarily on telomerase enzyme its function and mechanism of action. It also describes the interaction of telomerase enzyme with 1,3,4-Oxadiazole inhibitors including their structure activity relationships (SARs). With the knowledge of this molecular target, structural insights and SARs, this review may be helpful for (medicinal) chemists to design more potent, safe, selective and cost effective anti-cancer agents.

Liver cancer is one of serious diseases which threaten human life and health. Studies on the treatment of liver cancer have attracted widespread attention. Application of nano-drug delivery system (NDDS) can not only improve selective drug delivery to liver tissue and improve the bioavailability of drug, but also can reduce the side effects of drugs when it is specially modified in the respects of structure modification or specific target molecules decoration. This review will address the latest development of liver-targeted drug delivery system.

Background: The need for therapeutically effective anticancer drug delivery systems constantly persuades researchers to explore novel strategies. Objective: In this study a novel cubane based antibacterial nanocomposite was tailored as dual chemotherapy drug delivery vesicle in order to increase the therapeutic outcome in cancer therapy. Method: The physico-chemical characterization of engineered nanocarrier was assessed by Fourier transforms infrared spectroscopy (FTIR), Hydrogen nuclear magnetic resonance spectroscopy (1H NMR), Thermogravimetric analysis (TGA), and Field emission scanning electron microscopy-energy dispersive using X-ray (FESEMEDX). The antibacterial activity of novel developed nanocomposite was tested by determining minimum inhibitory concentration (MIC) values against Pseudomonas aeruginosa, Escherichia Coli and Candida albicans. Results: In order to investigate the efficacy of novel engineered nanocomposite (with average particle size of 50 nm) as dual anticancer drug delivery, DOX and MTX were bind to nanocarrier with encapsulation efficiency and loading content of around 97.3 ± 2.7% and 20.8 ± 1.6 %, respectively. Dual drugs released simultaneously with distinct tumor targeted, pH responsive sustained release manner. Moreover, the probable antitumoral activity of this engineered nanocomposite system against MCF7 cell lines was evaluated by MTT assay and cell cycle studies. The outcomes showed that novel engineered nanocomposite had no cytotoxic effects, while DOX@MTX-loaded nanocomposite possessed higher growth inhibition property and higher S-phase arrest as compared to cells treated with DOX@MTX alone. Conclusion: It was concluded that this novel cubane based drug delivery vehicle could process antibacterial and anticancer therapeutics spontaneously, representing promising tumor targeted system in nanomedicine.

Aims: In this study, discovery of novel anticancer agents acting by more than one mechanism was aimed. Method: For this purpose, eleven previously synthesized simple-stilbene, chalcone, flavanone derivatives and 31 novel stilbene-fused chalcones and stilbene-fused flavanones were tested for their aromatase inhibition, antiangiogenic and anti-proliferative properties in cancer (PC3, MCF-7) and healthy (HUVEC) cell lines. MTT cell viability assay was used to evaluate the anti-proliferative activities of the compounds. CYP19/MFC highthroughput screening kit (BD Biosciences, Oxford, UK) was used to search the aromatase inhibition properties and matrigel tube formation assay was applied to determine the anti-angiogenic activities. Results: Results indicate that the simple-chalcone and flavanone derivatives were more cytotoxic than the simple- stilbenes in the both cancer cell lines. In contrast, the simple-stilbene structures were much more effective at aromatase inhibition. The cytotoxicity profiles of stilbene-fused chalcones in cancer cells imply that these molecules mostly mimic the simple chalcone structures. On the other hand, flavanones lose their cytotoxic activities after becoming fused with stilbenes. Additionally, aromatase inhibition assays showed that stilbene-fused chalcones again do mimic the simple-chalcones but not simple-stilbenes and anti-angiogenic profiles of the tested molecules seem to be not related with stilbene fragments. Furthermore, stilbene-fused flavanones may mimic both simple-flavanones and simple-stilbenes depending upon the type and position of the substituent in their respective terminal aromatic rings.

Background: Retinoids which are vitamin A (Retinol) derivatives have been suggested to mediate the inhibition of cancer cell growth and apoptosis. It has been reported that all trans retinoic acid (ATRA) exhibited suppressive effects on different types of leukemia including chronic myelogenous leukemia. Objective: In the present study, we aim to find out the effects of 6 synthetic N-(3,5,5,8,8-pentamethyl-5,6,7,8- tetrahydronaphthalene-2-yl)-carboxamide derivatives (compound 6-12) on cell viability and apoptotic pathways in K562 human chronic myelogenous leukemia cell line. Methods: Cell viability and apoptosis were examined by spectrophotometric thiazolyl blue tetrazolium bromide (MTT) and caspase-3 assay, western blot, RT-PCR and flow cytometry. Results: Our results indicated that compound 6 (5-(1,2-Dithiolan-3-yl)-N-(3,5,5,8,8-pentamethyl-5,6,7,8- tetrahydronaphthalen-2-yl)pentanamide), 8 (4-(3,4-Dimethoxyphenyl)-N-(3,5,5,8,8-pentamethyl-5,6,7,8- tetrahydronaphthalen-2-yl)butanamide) and 11 (E-3-(4-Hydroxy-3-methoxyphenyl)-N-(3,5,5,8,8-pentamethyl- 5,6,7,8-tetrahydronaphthalen-2-yl)acrylamide) exhibited apoptotic effects in K562 human chronic myelogenous leukemia cell line and induced caspase 3, PARP cleavage, Bax/Bcl-2 ratio, Bad and Bim gene expressions. Conclusion: Some retinoid derivatives tested in this study induced apoptosis of K562 cells which suggest that these compounds may serve as potential agents in the treatment of chronic myelogenous leukemia.

Background: Quinazolines are a big family of heterocyclic compounds with anti-cancer properties. Objective: The latest investigation was on synthesis, characterization of novel 4-anilinoquinazoline derivatives for their anti-angiogenic effect. Method: A series of novel 4-anilino-6,7-dimethoxy quinazoline derivatives were synthesized and characterized using 1H, 13C NMR, FT-IR and LC-MS techniques. Cytotoxicity assays were performed for all compounds against different cell lines such as Human colon carcinoma (HCT116), Human chronic myeloid leukemia (K562) and Human breast cancer (SKBR3) cell lines using 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyl tetrazolium Bromide (MTT), Trypan blue and Lactose dehydrogenase release assay. The selected compounds were evaluated for their anti-tumor and anti-angiogenic effect on EAC tumor model. The molecular docking studies were drawn using maestro 2D sketcher and energy minimize was compounded by OPLS 2005. Results: Among all compounds, RB4 and RB7 showed moderate activity whereas RB1 showed most potent activity comparable with that of the standard drug cisplatin against all three cell lines. RB1 also inhibited the proliferation of tumor cells in three different cell lines. Further, in-vivo studies revealed that RB1 significantly reduced secretion of ascites, tumor cell proliferation and increased the life span of tumor bearing mice. The antiangiogenic effect of RB1 was revealed from the reduced vessel sprouting in the peritoneum region of treated mice and induced avascular zone in chorioallantoic membrane (CAM) model. The insilco molecular docking studies clearly demonstrate the dual inhibitory potential of RB1 against VEGFR-2 and EGFR from binding to the active site of its receptors. Conclusion: However these studies clearly show that RB1 might be a potent antitumor and anti-angiogenic agent representing a promising lead for further optimization and elucidation of the mechanism of action.

Background: Colon cancer is one of the most deadly and common carcinomas occurring worldwide and there have been many attempts to treat this cancer. The present work was designed in order to evaluate thymol as a potent drug against colon cancer. Materials and Methods: Cytotoxicity of thymol at different concentrations was evaluated against a human colon carcinoma cell line (HCT-116 cells). Fluorescent staining was carried out to evaluate the level of ROS as well as mitochondrial and DNA fragmentation and immunoblot analysis were performed to confirm apoptosis and mitoptosis. Results and Conclusion: Results of the study demonstrated that thymol efficiently created an oxidative stress environment inside HCT-116 cells, a colorectal carcinoma cell line, through induction of ROS production along with intense damage to DNA and mitochondria, as observed through Hoechst and rhodamine 123 staining, respectively. Moreover, expression of PARP-1, p-JNK, cytochrome-C and caspase-3 proteins was up-regulated, suggesting HCT-116 cells underwent mitoptotic cell death. Therefore, thymol could be used as a potent drug against colon cancer due to its lower toxicity and prevalence in natural medicinal plants.

Background: Among a wide range of pyridines, 3-cyanopyridines acquired a special attention due to their wide range of pharmacological activities especially the therapeutic activities. Many pharmacological drugs containing the pyridine nucleus were known in the market. Objective: The aim of this work was to synthesize target molecules not only possess anti-tumor activities but also kinase inhibitors. To achieve this goal, our strategy was to synthesize a series of 3-cyanopyridine derivatives using 2-aminoprop-1-ene-1,1,3-tricarbonitrile (1) as the key starting material for many heterocyclization reactions. Method: Muticoponent reactions were adopted using compound 1 to get different pyridine derivatives that were capable for different heterocyclization reactions. Results: Antiproliferative evaluations and c-Met kinase, Pim-1 kinse inhibitions were perform where some compounds gave high activities. Conclusion: Compounds that showed high antiprolifeative activity were tested gor c-Met-independent and the results showed that compounds 5c, 5e, 5f, 7c, 7f and 16d were more active than foretinib. The Pim-1 kinase inhibition activity of some selected compounds showed that compounds 5e and 16c were high potent to inhibit Pim-1 activity.

Abstract: Background: Alkynes are fundamental building blocks in synthetic chemistry with high pharmaceutical applications. Among the bioactive acetylenic molecules, propargylic alcohol is most important as almost all the marketed drugs contains quaternary centered propargylic alcohol functionality.

Objective: In this study we have synthesised and evaluated 3-hydroxy-3-ethynylindolin-2-one derivatives for in vitro cytotoxic activity.

Method: An expeditious method for direct alkynylation of isatins (ketones) has been developed using tetrabutylammonium fluoride (TBAF) as a catalyst in THF solvent at room temperature under metal-free conditions. Furthermore, this method is an economically viable process that also compliments green aspects like being a ligand/metal free process under ambient conditions. This reaction tolerated a wide range of substrates with good to excellent yields (80-94%).

Results: The results showed that the synthesized compounds (4m, 4n and 4p) has the ability to inhibit Akt kinase activity with IC50 values ranging from 7.7 to 9.8 μM.

Conclusion: All the 3-hydroxy-3-ethynylindolin-2-one derivatives were subjected for in vitro cytotoxic activity on five different cancer cell lines. Further, the synthesized compounds (4m, 4n and 4p) were evaluated for their ability to inhibit Akt kinase activity and exhibited good inhibition with IC50 values ranging from 7.7 to 9.8 μM..

Background: Capsicum plant, especially for C. annuum, is an abundant resource for bioactive antioxidants, but few studies have examined the unripe fruit part of the Capsicum plant. Objective: MeOH extract of unripe fruits of C. annuum L. var. conoides (UFCA) was chromatographed over a silica gel column using a gradient of CH2Cl2/MeOH as eluent to produce 9 fractions. Antioxidant activities are evaluated along with cell viabilities of 9 fractions of UFCA. Method: The antioxidant properties were analyzed in terms of total phenol content (TPC), total flavonoid content (TFC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, 2,2-azinobis (3-ethyl-benzothiazoline-6- sulfonic acid) (ABTS) radical scavenging, ferric reducing, and ferrous ion-chelating ability. The cell viability of human oral cancer cells (Ca9-22) was measured by 3-(4,5-dimethylthiazol-2-yl)-(3-carboxymethoxyphenyl)-2- (4-sulphophenyl)-2H-tetrazolium (MTS) assay. Results: Except for TFC, fractions (Frs.) 1 and 2 showed the lowest level of these antioxidant properties. Frs. 3 to 9 showed dose-responsive induction for antioxidant effects. Fr. 8 and Fr. 5 respectively showed the highest levels of TPC and TFC for 1162 ± 11 gallic acid equivalents (GAE) (mg)/UFCA (g) and 1295 ± 32 quercetin equivalents (QCE) (mg)/UFCA (g). The cell viability of Fr. 3 was moderately decreased (78.2%) while those of Frs. 4, 5, and 9 were dramatically decreased (55.6, 57.8, and 46.8%, respectively) in oral cancer Ca9-22 cells. UFCA-derived 14 compounds/mixtures derived from Frs. 1, 2, 3, 4, and 8 displayed differential antioxidant performance for these analyses. Conclusion: Taken together, fractions of UFCA displayed diverse antioxidant and anticancer effects for oral cancer cells. Some fractions of UFCA may be potent natural antioxidant supplements for antioral cancer cell treatment.