Anti-Cancer Agents in Medicinal Chemistry (Formerly Current Medicinal Chemistry - Anti-Cancer Agents) - Volume 17, Issue 3, 2017

Radionuclide antibody conjugates (RACs) and antibody-drug conjugates (ADCs) can function as biotherapeutic missiles in order to target cancer cells and destroy them. The advent of new technology platforms consisting of imaging modalities, drug design and radiochemistry will facilitate the personalised approach for cancer patient treatment programmes. The utilisation of radionuclides and cytotoxic drugs conjugated to biovectors can deliver a cytotoxic drug payload with the ability to emit alpha and/or beta particles in the vicinity of the tumour by binding onto the cancer cells surface antigens initiating cell death. This perspective aims to provide an insight into targeted therapies in the treatment of various cancerous disease states including breast cancer, prostate bone metastases, lymphoma and leukaemia.

Since its first description in 1955, tumor hypoxia has become a central issue in cancer treatment. Since then, it is essential to diagnose accurately the tumor oxygenation degree in order to establish the appropriate treatment. In this regard, a wide diversity of radiopharmaceuticals for in vivo imaging has been developed. Special conditions of the hypoxic microenvironment are low O2 partial pressure, enhanced levels of reductases, and genetic-adaptation-expression biomolecules involved in angiogenesis, erythropoiesis, cellular proliferation, apoptosis, metabolism- and glucose-uptake, local invasion, and metastatic spread. The development of radiolabeled hypoxia markers has been based on reductase substrates, like bioreductive ligands, or on entities capable of recognizing overexpressed proteins under hypoxia conditions, i.e. HIF-1α and carbonic anhydrase IX, among others. In this review these hypoxia markers are analyzed focusing on their medicinal chemistry characteristics.

Cancer remains as one of the major causes of death worldwide. The emergence of nanotechnology has opened new avenues for the development of nanoparticle (NP)- based diagnostic and therapeutic tools. NPs of different chemical composition, size, shape and surface decoration can be prepared using a wide variety of synthetic strategies. Subsequent radiolabelling with positron or gamma emitters results in potential diagnostic agents which may offer improved selectivity and/or specificity for the target organ or tissue, enabling the acquisition of images with higher signal-to-contrast ratio. Incorporation of alpha or beta emitters leads to therapeutic agents with application in the field of radiotherapy. Here, we first describe the different labeling strategies reported so far for the incorporation of radionuclides into NPs. Recent advances in the use of nanoparticulate constructs both in the diagnostic and therapeutic arenas are then discussed and examples of their application are briefly discussed.

Background: The use of nanobiomaterials is increasing each day. Among the immense variety of nanomaterials developed and studied the hydroxyapatite is one of the most ones. Objective: In this study we developed and tested nano-hydroxyapatite dopped with Ho-166 for bone cancer. Results: The results showed that the nano-hydroxyapatite dopped with Ho-166 has a great affinity for the bone. Conclusion: The pre-clinical studies support the use as a nano-radiopharmaceuticals for bone cancer treatment and diagnosis.

Background: Chemotherapy is one of the most common approaches for cancer treatment. Particularly Doxorubicin has been proven to be effective in the treatment of many soft and solid tumors for locally advanced and metastatic cancer. It is not easy to clinically evaluate the chemotoxic or chemoprotective effect of some drugs, even more when there is a subclinical toxicity. Objective: To determine the usefulness of the hepatobiliary, colloid and cardiac scintigraphies, employing^99mTcdisida, ^99mTc-phytate and ^99mTc-sestamibi respectively, in the evaluation of the hepato and cardiotoxicity of two chemotherapeutic treatments assessed in rats. Method: Two groups were submitted to doxorubicin (DOX) treatment and one was co-administered with histamine (DOX+HIS). Static ^99mTc-phytate and ^99mTc-sestamibi scintigraphies as well as a dynamic ^99mTc-disida study were performed in a small field of view gamma camera at: 0 weeks (control), 1 week and 2 weeks of treatment. Imagenological parameters were calculated: Liver/Bone Marrow ratio (L/BM), Heart/Background ratio (H/B) and time to the maximum (Tmax) for 99mTc-phytate, 99mTc-sestamibi and 99mTc-disida extraction, respectively. Results: Control (L/BM= 98±3; H/B=2.3±0.4; Tmax=8±3), DOX (L/BM: 85±3, 80±3; H/B, 3.5±0.5, 3.3±0.5 and Tmax 6±1, 4±1) for 1 and 2 weeks respectively and DOX+HIS (L/BM: 99±0.3, 98±1; H/B 2.9±0.5, 2.9±0.5 and Tmax, 8±2, 9±2) for 1 and 2 weeks, respectively. Histological analysis showed cardio and hepatotoxicity induced by doxorubicin. Conclusion: Imagenological parameters showed differences among treated and control groups and between both chemotherapy treatments. Thus, these radiopharmaceutical functional approaches were able to reflect heart and liver toxicity produced by doxorubicin.

Pancreatic cancer is one of the most aggressive human cancers and is expected to surpass breast cancer to become the third chief cause of cancer-related deaths in the United States. While conventional treatment approaches such as surgery and classic chemotherapy have slightly improved the relative five year survival rate to 8% yet it is the lowest survival rate for any major cancer. This emphasizes the serious need of more effective and well tolerated therapies to reverse the poor prognosis of the defined neoplasm. Aberrant expression of histone deacetylase (HDAC) enzymes has been implicated in pancreatic cancer signalling. The inhibitors of these enzymes namely HDAC inhibitors (HDACi) are the novel agents which are currently being tested. These inhibitors modulate both histone and nonhistone proteins and have shown multiple biological effects including cell cycle arrest, differentiation and apoptosis in several cancer models. This article focuses on plant-derived HDAC inhibitor Sulforaphane (SFN) as a promising antipancreatic cancer agent. Moreover, we discuss the distinct molecular mechanisms triggered by SFN to exert cytotoxic effect in the predefined cancer models. Finally we describe the combinatorial therapeutic strategy involving SFN with other anticancer agents. This novel approach circumvents herculean cancer chemoresistance and alleviates toxicity, the main drawbacks of monotherapy.

Breast cancer is the heterogeneous disease and leading cause of death in women, worldwide. It is generally caused by the perturbation of various signaling pathways responsible for cell apoptosis. Due to genetic variability, different signaling pathways are disrupted in different breast cancer patients; so, to overcome this multifaceted condition, the personalized treatment is preferred. Since, various potential targets exist in breast cancer cells; it raised the need of new prospective of lead compounds. A large number of evidences show that, due to the presence of various secondary metabolites in plants, natural compounds are frequently examined for search of new bioactive molecules. This review includes the pathological aspects of breast cancer and the effect of natural compounds on breast cancer cells along with their possible mechanism of action. (Databases searched were PubMed, Science Direct, Web of Knowledge, Scopus, and Google Scholar).

Metabolic reprograming contributes to esophageal tumorigenesis. A better understanding of how esophageal cancer (EC) cells reactivate primitive signaling to retain glucose metabolism under unfavorable conditions is essential for the development of therapeutic interventions to treat EC. Current achievements in the field of EC glucose metabolism have been critically reviewed to address several fundamental questions. These include: 1) the association of abnormal glucose metabolism and EC risk; 2) alterations of genes and/or proteins that contribute to glucose oncometabolism in EC; 3) signal transduction pathways that promote EC consumption of glucose; and, 4) targeting the glycolytic element or the EC dependency on excessive glucose consumption to prevent growth of EC caused by different genomic changes.

Background: Coumarins possess a broad spectrum of biological activities and are important pharmacophores in drug developments. Since aberrant upregulation of PI3K/Akt signaling is related to uncontrolled tumor cell proliferation, enhanced migration, and adhesion-independent tumor growth, it is of interests to find novel coumarin derivatives as anticancer agents targeting the PI3K/Akt signaling pathway. Objective: A variety of coumarin derivatives possessing the pyridinylurea units were designed to increase their potency and isoform selectivity against PI3Ks. Method: Novel coumarin analogs 4a–m were were prepared from 5-methylpyridin-2-ylamine in a straightforward way and their growth inhibitory activity against tumor cells was evaluated by a MTT assay. The inhibitory activity against PI3Kα, β, δ and γ was measured by luminescent assay. Akt phosphorylation inhibition and caspase 3 and PARP activation were measured by Western blot analysis. Apoptosis was measured by staining cells with annexin V-FITC and 7-AAD. Results: In general, these coumarin analogs exhibited good in vitro growth inhibitory activities against tumor K562, Hela, A549 and MCF-7 cells. Some of them showed comparable or better potency than BENC-511. Compounds 4b and 4h were much more potent PI3K inhibitors than S14161 or BENC-511. In addition, 4b was more selective to PI3Kα/β over PI3Kδ/γ, while 4h was a selective PI3Kα/β/δ inhibitor. Moreover, 4h could suppress the phosphorylation of Akt and induce K562 cell apoptosis. Conclusion: Coumarin derivatives possessing the pyridinylurea units are potential PI3K inhibitors and anticancer agents. These findings will be helpful for the future design of more potent and selective PI3K inhibitors.

Background: The number of cancer cases around the world has increased according to the World Health Organization (WHO) reports, nearly 14 million new cases and 8.2 million cancer associated mortalities have been reported in 2012. Chemotherapeutic resistance is a major problematic issue in the management of patients with breast tumor. Objective: In this study, the apoptotic gene profile of 4T1 mouse breast cancer cells treated with MC-A in combination with cisplatin or epirubicin was evaluated to decipher the possible apoptotic molecular targets. Methods: The effects of MC-A in combination with cisplatin (CIS) or epirubicin (EPI) on cytotoxicity, cell migration, wound healing, clonogenicity along with enhanced effect of these combinations on 84 apoptosis related genes were tested in 4T1 cancer cells. Results: MC-A in combination with epirubicin or cisplatin robustly induced cytotoxicity in 4T1 cells in vitro. MC-A in combination with cisplatin or epirubicin showed significantly inhibition of cell migration compared to treatment with each agent alone. Genes involved in positive regulation of apoptosis, negative regulator of apoptosis, death-like, mitochondrial apoptotic signaling, induction of apoptosis through DR3 and DR4/5 death receptors, and anti-apoptosis were highly affected in MC-A+cisplatin or MC-A+epirubicin combinations compared to each agent only. Conclusions: In conclusion, the apoptotic response of 4T1 cancer cells to chemotherapeutic drugs occurs in different ways. MC-A in combination with these chemotherapeutic drugs could modulate the expression of genes involved in both extrinsic and intrinsic pathways of apoptosis, leading to higly effective apoptotic signalling in cancer treatment.

Background: Inflammation substantially contributes to the development and progression of malignancies. cancer-related inflammation, has been proposed to promote tumor progression and serve as the seventh hallmark of tumor. Tumor microenvironment, products of inflammatory cells influence almost every aspect of tumorigenesis and tumor progression. Objective: The aim of this study was to design and evaluate drug candidates targeting cancer-related inflammation. Method: A series of 4-hydroxy- 3-(2- (2-[2- [(substituted phenyl)methylidene]hydrazin-1- yl]-1,3- thiazol-5- yl)-1- phenylethyl)-2H-chromen- 2-one (4a-j) were synthesized for its potential activity towards COX-2 inhibition and anticancer activity against MCF-7 and EAC cell lines. The structures of the synthesized compounds were elucidated using spectral data. Docking study was also performed to determine the probable binding mode of the compounds into the active site. Results: Compound 4b showed significant anti-inflammatory and anticancer activity. Conclusion: According to the results, it was concluded that designing compounds targeting cancer-related inflammation could be helpful in developing promising drug candidates for the treatment of cancer.

Background: Copper has shown to be useful in disorders with an inflammation origin such as cancer [1-3]. It has previously shown that Casiopeínas^® interact with DNA and promote the disruption by a mechanism related to the increase in the level of free radicals [4-6] which confers antineoplastic potential. Objetive: The aim of the present work was to study the antitumor effects of a series of Cu(II) complexes with saccharinate (sac) and glutamate (gln): [Cu(sac)2(H2O)4].2H2O (Cu-sac), [Cu(gln)2] (Cu-gln) and Na2[Cu(sac)2 (gln)2].H2O (Cu-sac-gln). Methods: We have investigated the action of these compounds on cell viability on human osteosarcoma cells MG-63. In particular, we pay special attention to the cyto and genotoxicity actions of these complexes and to the association to oxidative stress. Results: The three complexes: Cu-sac, Cu-gln and Cu-sac-gln caused a decline in cell viability. The half-maximal inhibitory concentration in MG-63 cells for Cu-sac-gln is 170 μM, showing the strongest antiproliferative effect. Moreover, only Cu-sac-gln caused a decrease of the mitochondrial activity from 100 μM. Our results indicate that the copper(II) complexes studied here produce DNA damage and suggest that the rise of reactive oxygen species (ROS) is the central mechanism action. Genotoxicity studied by the Cytokinesis-block micronucleus (MN) assay and the Single cell gel electrophoresis (comet assay) could be observed in MG-63 cells treated with Cu-sac-gln from 100 and 50 μM, respectively. Cu-sac and Cu-gln also induced DNA damage; however their effect was definitively weaker. The generation of reactive oxygen species increased from 50 μM of Cu-sac-gln and Cu-sac and only from 250 μM of Cugln, as well as a reduction of the GSH/GSSG ratio from 50 μM. When cells were treated with several concentrations of the complexes in addition to a combination of 50 μM of vitamin C plus 50 μM of vitamin E, a total recovery in cell survival was obtained for Cu-gln in the whole range of tested concentrations while only a partial viability recovery was obtained from 250 μM of Cu-sac and Cu-sac-gln. Conclusion: Overall, our results point to a differential cyto- and genotoxicity of the three copper(II) complexes and demonstrate that the complexation with both ligands confers the most potent antitumor action in human osteosarcoma cells.

Background: Poly(hydroxyalkanoates) (PHA) have recently attracted increasing attention due to their biodegradability and high biocompatibility, which makes them suitable for the development of new prolong drug formulations. Objective: This study was conducted to develop new prolong paclitaxel (PTX) formulation based on poly(3- hydroxybutyrate) (PHB) microparticles. Method: PHB microparticles loaded with antitumor cytostatic drug PTX were obtained by spray-drying method using Nano Spray Dryer B-90. The PTX release kinetics in vitro from PHB microparticles and their cytotoxity on murine hepatoma cell line MH-22a were studied. Microparticles antitumor activity in vivo was studied using intraperitoneally (i.p.) transplanted tumor models: murine Lewis lung carcinoma and xenografts of human breast cancer RMG1. Results: Uniform PTX release from PHB-microparticles during 2 months was observed. PTX-loaded PHB microparticles have demonstrated a significant antitumor activity versus pure drug both in vitro in murine hepatoma cells and in vivo when administered i.p. to mice with murine Lewis lung carcinoma and xenografts of human breast cancer RMG1. Conclusion: The developed technique of PTX sustained delivery from PHB-microparticles has therapeutic potential as prolong anticancer drug formulation.

Background and Objective: The clinical success of the chemotherapeutic drugs is restricted by the nonspecific toxicity-related adverse side effects. The diverse implication of indoles and thiazoles in medicinal chemistry prompted us to develop a new series of novel 2-aryl-amino-4-(3′-indolyl)thiazoles as more effective and less toxic anti-cancer compounds. Method and Results: One-pot microwave-assisted rapid and high yielding synthesis of 2-arylamino-4-(3′- indolyl)thiazoles involved the reaction of easily available α-tosyloxy-ketones with N-arylthioureas in polyethylene glycol-400 (PEG-400). In vitro cytotoxicity study of 2-arylamino-4-(3′-indolyl)thiazoles against a panel of human cancer cell lines by MTT assay revealed IC50 values in the low micromolar range. Of the fifteen synthesized arylaminothiazoles, compounds 17b, 17d, 17g and 17il showed significant anti-proliferative activity against the selected cancer cell lines with IC50 < 10 μM. The compound 17b was identified as the most potent ligand of the series, which exhibited good cytotoxic activity against MCF-7 breast cancer cells with an IC50 value of 1.86 μM but minimal toxicity on normal human cells. Investigation of the underlying mechanism by flow cytometry indicated that 17b induced ROS-mediated apoptosis in MCF-7 cells in a dose-dependent manner as supported by upregulation of Bax and caspase-3 and down-regulation of Bcl-2 (by Western blot). Conclusion: Developed an efficient and eco-friendly synthesis for 2-arylamino-4-(3′-indolyl)thiazoles, and their in vitro cytotoxicity studies demonstrate that compound 17b exhibits significant anti-proliferative activity against MCF-7 (breast cancer) cells by activating ROS-mediated apoptosis through the mitochondrial apoptosis pathway.

Background: The present study emphasizes on designing a new series of isatin-dihydropyrimidinone derivatives by adopting a hybrid pharmacophore approach. Fe3O4 nanoparticles (Fe3O4 NP) are magnetically recoverable and are effective catalysts adequately used to synthesize Isatin-dihydropyrimidinones. Individual derivatives of Isatin and dihydropyrimidinone are equipotent to treat cytotoxicity. Objective: The present work was planned to fuse two pharmacophores (Isatin, dihydropyrimidinone) and to examine any synergistic effect in the anticancer activity. Method: The individual compounds are synthesized by adopting appropriate synthetic routes like sandmayers and biginellis reaction and are fused together by using glacial acetic acid and Methanolic KOH to form novel Isatindihydropyrimidinone hybrids. All the new series of hybrids 7a-l were characterized by FT-IR, ¹H NMR, ¹³C NMR, elemental analysis and Mass spectroscopy. The antioxidant activity of the synthesized compounds was assessed by using two models: 1, 1-diphenyl-2-picryl-hydrazyl (DPPH) and Hydrogen peroxide (H2O2) scavenging assay. Results: From the results it can be inferred that nearly all the synthesized compounds have shown antioxidant activity at the tested dose as correlated with the standard ascorbic acid. The in vitro cytotoxic activity was assayed by using MTT assay. Compound 7l with IC50 values 22.13, 25.68 and 35.59 μM has significantly greater potency against MCF- 7, HeLa and IMR-32 cell lines. Conclusion: The compounds with halogen and electron withdrawing groups at the C-5 position of isatin ring exhibited significant antioxidant and cytotoxic activity.

Background: Globally, cancer is regarded as one of the biggest health concern in humans and animals and is one of the most terrifying diseases. Therefore, there is a necessity for the discovery, development and improvement of novel antitumor drug molecules which could efficiently prevent proliferative pathways and clonal expansion of cells. Heterocyclic compounds like benzochromene play a key role in the development of current pharmaceuticals, natural resources, agriculture products, analytical reagents and dyes. Therefore, anticancer drugs show increased resistance, it is essential to designing the novel structured heterocyclic moieties to create potential anticancer agents with promising biological applications. Objective: To synthesis a novel 1-(substitutedphenyl)-2-(1H-tetrazol-5-yl)-1H-benzo[f]chromene-3-amine derivatives for in vitro antitumour activity. Method: The reaction of 3-amino-1-(substitutedphenyl)-1H-benzo[f]chromene-2-carbonitrile with sodium azide, ammonium chloride in dimethyl formamide solvent under reflux condition for 4 h afforded products (3a-k). The synthesized molecules were subjected to possible potential anti-tumour activity in vitro in four human cancer cell lines (MCF-7, Caco-2, HeLa and SKBR-3), and one human non-cancer cell line (HEK293), using the MTT cell viability assay. Results: A novel series of products (3a-k) were synthesized with good yield and were identified with ¹H NMR, ¹⁵N NMR, ¹³C NMR, FT-IR and HR-MS spectrum. The most potent compounds 3d, 3e, and 3f possessing the greatest cytotoxicity activity with IC50 values slightly higher (15-33 μM) than that of 5-Fluorouracil (10-17 μM), indicating their potential to be antitumor agents. The 3a, 3b, 3c, 3h, 3i and 3j compounds showed moderate activity. Additionally, a molecular docking analysis was conducted to predict the multi-drug resistance modulator behavior of synthesized compounds in the ATP binding site of P-glycoprotein. Conclusions: We synthesized and designated eleven novel derivatives of tetrazole linked benzochromenes (3a-k) and evaluated their anti-cancer activity. Additionally, the results from the docking studies were found to be in good agreement with the results from computational profiling.