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Three groups of novel analogs of combretastatin-A4 (CA-4), viz., the N1-phenyl-pyrazoline (5a–e), N1-alkyl acetylated pyrazoline (6a–c), and N1-phenyl acetylated pyrazoline (7a–g) were designed, and synthesized in good yield. The structure of the compounds was confirmed by spectroscopic techniques. All the compounds were evaluated for their in vitro anticancer (MCF-7 cell line), antioxidant (DPPH, NO, SOR, and H2O2), and anti-inflammatory activity. Compounds 5d, 7g, 7f, 7e, 7c, 5b, 6a, 7b, and 7a showed excellent potency with GI50 ranging from 0.1 to 10.9 µM against the MCF-7 cell line. Compounds 7f, 7g, 5c, 5d, 5b, 7e, and 6a exhibited good anti-inflammatory activity. Encouraged by these results, all the compounds were also tested for their antioxidant potency. Compounds 6a, 6c, 7b, 7c, 7f, and 7g were found to be excellent scavengers of all four free radicals (DPPH, NO, SOR, and H2O2). [ABSTRACT FROM AUTHOR]

Combretastatins isolated from the Combretum caffrum tree belong to a group of closely related stilbenes. They are colchicine binding site inhibitors which disrupt the polymerization process of microtubules in tubulins, causing mitotic arrest. In vitro and in vivo studies have proven that some combretastatins exhibit antitumor properties, and among them, combretastatin A-4 is the most active mitotic inhibitor. In this study, a series of novel combretastatin A-4 analogs containing carboxylic acid, ester, and amide moieties were synthesized and their cytotoxic activity against six tumor cell lines was determined using sulforhodamine B assay. For the most cytotoxic compounds (8 and 20), further studies were performed. These compounds were shown to induce G0/G1 cell cycle arrest in MDA and A549 cells, in a concentration-dependent manner. Moreover, in vitro tubulin polymerization assays showed that both compounds are tubulin polymerization enhancers. Additionally, computational analysis of the binding modes and binding energies of the compounds with respect to the key human tubulin isotypes was performed. We have obtained a satisfactory correlation of the binding energies with the IC50 values when weighted averages of the binding energies accounting for the abundance of tubulin isotypes in specific cancer cell lines were computed. [ABSTRACT FROM AUTHOR]

Cancer is defined as the group of diseases which involve abnormal cell growth or controlled growth of abnormal cells that are present in any part of the body. The causative agents of cancer are chemical, environmental, viral, and mutagenic, which lead to the mutation of genes into oncogenes, which provoke or demean regulatory biochemicals, resulting in accelerated cellular growth. Combretastatin was selected as the candidate because it is a water-soluble prodrug which is quickly converted into combretastatin A4, a cancer-fighting substance. It has longer circulation, better drug targeting, increased efficiency, and fewer side effects. The research was carried out to find a potential drug that could inhibit the action of cancer in humans. In the experiment, 21 derivatives of combretastatin were subjected to molecular docking for analyzing the binding interactions of the derivative with the active site using the Protein Data Bank: 3DK9 through Molegro Virtual Docker 6.0. The docking showed that the (E)-1-(2,6-dimethoxypyridin-4-yl)-3-(1H-indol-3-yl)-2-methylprop-2-en-1-one was the most potent, had a Mol Dock score of-194.925 and gave interactions with Asp331, Gly31, and Thr57. Thus, this research can be further extended further to have more potent drugs.

Cancer is defined as the group of diseases which involve abnormal cell growth or controlled growth of abnormal cells that are present in any part of the body. The causative agents of cancer are chemical, environmental, viral, and mutagenic, which lead to the mutation of genes into oncogenes, which provoke or demean regulatory biochemicals, resulting in accelerated cellular growth. Combretastatin was selected as the candidate because it is a water-soluble prodrug which is quickly converted into combretastatin A4, a cancer-fighting substance. It has longer circulation, better drug targeting, increased efficiency, and fewer side effects. The research was carried out to find a potential drug that could inhibit the action of cancer in humans. In the experiment, 21 derivatives of combretastatin were subjected to molecular docking for analyzing the binding interactions of the derivative with the active site using the Protein Data Bank: 3DK9 through Molegro Virtual Docker 6.0. The docking showed that the (E)-1-(2,6-dimethoxypyridin-4-yl)-3-(1H-indol-3-yl)-2-methylprop-2-en-1-one was the most potent, had a Mol Dock score of-194.925 and gave interactions with Asp331, Gly31, and Thr57. Thus, this research can be further extended further to have more potent drugs. [ABSTRACT FROM AUTHOR]

In the present work, a series of 1,2,4-triazole derivatives are designed as combretastatin A-4 analogs with the 4-nitrophenyl group and different aliphatic alkyl substituents, the designed compounds were synthesized and characterized by FT-IR, 1H NMR,13C NMR spectroscopy, and mass spectrometry. The synthesized compounds were tested as antiproliferative agents against human cancer laryngeal (Hep-2) cell line, the cytotoxicity of the synthesized compounds was evaluated by the treatment of a human normal kidney (Vero) cell line. The obtained results revealed that compound 5c, which has a n-propyl substituent, is the most active one and has lowest cytotoxicity against normal cells. This compound has the lowest IC50 value within the tested series; consequently, compound 5c could be considered a promising antiproliferative agent and a good candidate for further pharmacological studies. Molecular docking studies were implemented to determine the affinity of the synthesized compound toward the colchicine binding site. [ABSTRACT FROM AUTHOR]

Combretastatins isolated from the Combretum caffrum tree belong to a group of closely related stilbenes. They are colchicine binding site inhibitors which disrupt the polymerization process of microtubules in tubulins, causing mitotic arrest. In vitro and in vivo studies have proven that some combretastatins exhibit antitumor properties, and among them, combretastatin A-4 is the most active mitotic inhibitor. In this study, a series of novel combretastatin A-4 analogs containing carboxylic acid, ester, and amide moieties were synthesized and their cytotoxic activity against six tumor cell lines was determined using sulforhodamine B assay. For the most cytotoxic compounds (8 and 20), further studies were performed. These compounds were shown to induce G0/G1 cell cycle arrest in MDA and A549 cells, in a concentration-dependent manner. Moreover, in vitro tubulin polymerization assays showed that both compounds are tubulin polymerization enhancers. Additionally, computational analysis of the binding modes and binding energies of the compounds with respect to the key human tubulin isotypes was performed. We have obtained a satisfactory correlation of the binding energies with the IC50 values when weighted averages of the binding energies accounting for the abundance of tubulin isotypes in specific cancer cell lines were computed.

LASSBio-1920 was synthesized due to the poor solubility of its natural precursor, combretastatin A4 (CA4). The cytotoxic potential of the compound against human colorectal cancer cells (HCT-116) and non-small cell lung cancer cells (PC-9) was evaluated, yielding IC50 values of 0.06 and 0.07 μM, respectively. Its mechanism of action was analyzed by microscopy and flow cytometry, where LASSBio-1920 was found to induce apoptosis. Molecular docking simulations and the enzymatic inhibition study with wild-type (wt) EGFR indicated enzyme-substrate interactions similar to other tyrosine kinase inhibitors. We suggest that LASSBio-1920 is metabolized by O-demethylation and NADPH generation. LASSBio-1920 demonstrated excellent absorption in the gastrointestinal tract and high central nervous system (CNS) permeability. The pharmacokinetic parameters obtained by predictions indicated that the compound presents zero-order kinetics and, in a human module simulation, accumulates in the liver, heart, gut, and spleen. The pharmacokinetic parameters obtained will serve as the basis to initiate in vivo studies regarding LASSBio-1920's antitumor potential. [ABSTRACT FROM AUTHOR]

The present study evaluated the efficacy of nano-formulated water-soluble kaempferol and combretastatin alone and combined against the native kaempferol and combretastatin on angiogenesis. The solvent evaporation method was used to synthesize the nano-formulated water-soluble kaempferol and combretastatin and characterized using various analyses such as dynamic light scattering (DLS) and Fourier-transform infrared (FT-IR) spectroscopy.The anti-angiogenic activity of native, nano-formulated water-soluble kaempferol and combretastatin was investigated by cell viability on HUVEC and A498 cell lines, while chick chorioallantoic membrane (CAM) assay was utilized to assess morphometric and histopathological changes, and mRNA expressions of VEGF-A and FGF2 using qRT-PCR. MTT assay results revealed that the combination of nano-formulated water-soluble kaempferol and combretastatin significantly reduced the cell viability compared to control, individual treatments of native, nano-formulated water-soluble kaempferol, and combretastatin. Morphometric analysis of CAM showed that treatment with nano-formulated water-soluble kaempferol and combretastatin caused a substantial decrease in density, vessel network, branch points, and nets of CAM blood vessels. The histopathological results of CAM showed the irregular shape of blood vessels at the thin stratum of chronic endoderm, and blood capillaries were diminished compared to the control. In addition, the mRNA expression levels of VEGF-A and FGF2 were significantly decreased compared with native forms. Therefore, the findings of this study indicate that nano-formulated water-soluble combretastatin and kaempferol suppress angiogenesis by preventing the activation of endothelial cells and suppressing factors of angiogenesis. Moreover, a combination of nano-formulated water-soluble kaempferol and combretastatin worked much better than individual treatments.

A series of new combretastatin A4 derivatives (6a-6c, 9a-12c) containing nitrogen atoms and nitrogen heterocycles were synthesized by condensation reaction, reduction reaction, hydrolysis reaction and Crutius rearrangement, and the structures were confirmed by 1H NMR, 13C NMR and Mass spectrum. The antitumor cytotoxicity of a series of newly synthesized compounds were evaluated in vitro toward the cell line of hepatoma cell with erianin as positive control. Amoung all the compound, 6b exhibit the most antitumor activity against HepG2 (Human hepatoellular carcinomas) cell line with the inhibition rate 93.85%, and the other compounds also showed moderate to potent antitumor activity. To understand the interaction of series with active binding site of receptor, docking study was performed with VEGFR-2 (Vascular Endothelial Growth Factor Receptor 2) kinase domain in complex with axitinib using Sybyl. The compound with the highest total score was 9c, reaching 8.92, which was higher than that of the positive control erianin This research highlights the therapeutic potential of novel VEGFR-2 inhibitors in treating cancers and provides a promising strategy for drug discovery. [ABSTRACT FROM AUTHOR]

The solid-phase microextraction technique quantifies analytes without considerably affecting the sample composition. Herein, a proof-of-concept study was conducted to demonstrate the use of coated probe electrospray ionization (coated-PESI) and coated blade spray (CBS) as ambient mass spectrometry approaches for monitoring drug biotransformation. The ability of these methods was investigated for monitoring the dephosphorylation of a prodrug, combretastatin A4 phosphate (CA4P), into its active form, combretastatin A4 (CA4), in a cell culture medium supplemented with fetal bovine serum. The CBS spot analysis was modified to achieve the same extraction efficiency as protein precipitation and obtained results in 7 min. Because coated-PESI performs extraction without consuming any samples, it is the preferred technique in the case of a limited sample volume. Although coated-PESI only extracts small quantities of analytes, it uses the desorption solvent volume of 5–10 pL, resulting in high sensitivity, thus allowing the detection of compounds after only 1 min of extraction. The biotransformation of CA4P into CA4 via phosphatases occurs within the simple matrix, and the proposed sample preparation techniques are suitable for monitoring the biotransformation.

Simple Summary: Vascular-disrupting agents promise significant therapeutic efficacy against solid tumors by selectively damaging tumor-associated vasculature. Following administration of the phosphate prodrug OXi6197, dynamic bioluminescence imaging revealed dose-responsive vascular shutdown in MDA-MB-231 human breast tumor xenografts and for the first time murine RENCA kidney tumors. Rapid vascular disruption was observed, which continued over 24 h. Histology showed vascular congestion, hemorrhage and necrosis. Twice-weekly doses of OXi6197 caused a significant growth delay in MDA-MB-231 breast tumors and many RENCA kidney tumors growing orthotopically in mice. The vascular disrupting activity of a promising tubulin-binding agent (OXi6196) was demonstrated in mice in MDA-MB-231 human breast tumor xenografts growing orthotopically in mammary fat pad and syngeneic RENCA kidney tumors growing orthotopically in the kidney. To enhance water solubility, OXi6196, was derivatized as its corresponding phosphate prodrug salt OXi6197, facilitating effective delivery. OXi6197 is stable in water, but rapidly releases OXi6196 in the presence of alkaline phosphatase. At low nanomolar concentrations OXi6196 caused G2/M cell cycle arrest and apoptosis in MDA-MB-231 breast cancer cells and monolayers of rapidly growing HUVECs underwent concentration-dependent changes in their morphology. Loss of the microtubule structure and increased bundling of filamentous actin into stress fibers followed by cell collapse, rounding and blebbing was observed. OXi6196 (100 nM) disrupted capillary-like endothelial networks pre-established with HUVECs on Matrigel®. When prodrug OXi6197 was administered to mice bearing orthotopic MDA-MB-231-luc tumors, dynamic bioluminescence imaging (BLI) revealed dose-dependent vascular shutdown with >80% signal loss within 2 h at doses ≥30 mg/kg and >90% shutdown after 6 h for doses ≥35 mg/kg, which remained depressed by at least 70% after 24 h. Twice weekly treatment with prodrug OXi6197 (20 mg/kg) caused a significant tumor growth delay, but no overall survival benefit. Similar efficacy was observed for the first time in orthotopic RENCA-luc tumors, which showed massive hemorrhage and necrosis after 24 h. Twice weekly dosing with prodrug OXi6197 (35 mg/kg) caused tumor growth delay in most orthotopic RENCA tumors. Immunohistochemistry revealed extensive necrosis, though with surviving peripheral tissues. These results demonstrate effective vascular disruption at doses comparable to the most effective vascular-disrupting agents (VDAs) suggesting opportunities for further development. [ABSTRACT FROM AUTHOR]

Solid tumours vary in sensitivity to the vascular disrupting agent combretastatin A-4 3-O-phosphate (CA4P), but underlying factors are poorly understood. The signaling sphingolipid, sphingosine-1-phosphate (S1P), promotes vascular barrier integrity by promoting assembly of VE-cadherin/β-catenin complexes. We tested the hypothesis that tumour pre-treatment with S1P would render tumours less susceptible to CA4P. S1P (1μM) pretreatment attenuated an increase in endothelial cell (HUVEC) monolayer permeability induced by 10μM CA4P. Intravenously administered S1P (8mg/kg/hr for 20 minutes then 2mg/kg/hr for 40 minutes), reduced CA4P-induced (30mg/kg) blood flow shut-down in fibrosarcoma tumours in SCID mice (n≥7 per group), as measured by tumour retention of an intravenously administered fluorescent lectin. A trend towards in vivo protection was also found using laser Doppler flowmetry. Immunohistochemical staining of tumours ex vivo revealed disrupted patterns of VE-cadherin in vasculature of mice treated with CA4P, which were decreased by pretreatment with S1P. S1P treatment also stabilized N-cadherin junctions between endothelial cells and smooth muscle cells in culture, and stabilized tubulin filaments in HUVEC monolayers. We conclude that the rapid shutdown of tumour microvasculature by CA4P is due in part to disruption of adherens junctions and that S1P has a protective effect on both adherens junctions and the endothelial cell cytoskeleton.

LASSBio-1920 was synthesized due to the poor solubility of its natural precursor, combretastatin A4 (CA4). The cytotoxic potential of the compound against human colorectal cancer cells (HCT-116) and non-small cell lung cancer cells (PC-9) was evaluated, yielding IC50 values of 0.06 and 0.07 μM, respectively. Its mechanism of action was analyzed by microscopy and flow cytometry, where LASSBio-1920 was found to induce apoptosis. Molecular docking simulations and the enzymatic inhibition study with wild-type (wt) EGFR indicated enzyme-substrate interactions similar to other tyrosine kinase inhibitors. We suggest that LASSBio-1920 is metabolized by O-demethylation and NADPH generation. LASSBio-1920 demonstrated excellent absorption in the gastrointestinal tract and high central nervous system (CNS) permeability. The pharmacokinetic parameters obtained by predictions indicated that the compound presents zero-order kinetics and, in a human module simulation, accumulates in the liver, heart, gut, and spleen. The pharmacokinetic parameters obtained will serve as the basis to initiate in vivo studies regarding LASSBio-1920’s antitumor potential.

The solid-phase microextraction technique quantifies analytes without considerably affecting the sample composition. Herein, a proof-of-concept study was conducted to demonstrate the use of coated probe electrospray ionization (coated-PESI) and coated blade spray (CBS) as ambient mass spectrometry approaches for monitoring drug biotransformation. The ability of these methods was investigated for monitoring the dephosphorylation of a prodrug, combretastatin A4 phosphate (CA4P), into its active form, combretastatin A4 (CA4), in a cell culture medium supplemented with fetal bovine serum. The CBS spot analysis was modified to achieve the same extraction efficiency as protein precipitation and obtained results in 7 min. Because coated-PESI performs extraction without consuming any samples, it is the preferred technique in the case of a limited sample volume. Although coated-PESI only extracts small quantities of analytes, it uses the desorption solvent volume of 5–10 pL, resulting in high sensitivity, thus allowing the detection of compounds after only 1 min of extraction. The biotransformation of CA4P into CA4 via phosphatases occurs within the simple matrix, and the proposed sample preparation techniques are suitable for monitoring the biotransformation. [Display omitted] • Solid-phase microextraction direct mass spectrometry is used for drug biotransformation. • SPME protocol is developed for a rapid time-course analysis of metabolism reactions. • Phosphate prodrug is converted to active form via FBS phosphatases. [ABSTRACT FROM AUTHOR]

As per World Health Organization cancer remains as a leading killer disease causing nearly 10 million deaths in 2020. Since the burden of cancer increases worldwide, warranting an urgent search for anti-cancer compounds from natural sources. Secondary metabolites from plants, marine organisms exhibit a novel chemical and structural diversity holding a great promise as therapeutics in cancer treatment. These natural metabolites target only the cancer cells and the normal healthy cells are left unharmed. In the emerging trends of cancer treatment, the natural bioactive compounds have long become a part of cancer chemotherapy. In this review, we have tried to compile about eight bioactive compounds from plant origin viz. combretastatin, ginsenoside, lycopene, quercetin, resveratrol, silymarin, sulforaphane and withaferin A, four marine-derived compounds viz. bryostatins, dolastatins, eribulin, plitidepsin and three microorganisms viz. Clostridium, Mycobacterium bovis and Streptococcus pyogenes with their well-established anticancer potential, mechanism of action and clinical establishments are presented. [ABSTRACT FROM AUTHOR]

A series of pyrazoline bridged combretastatin analogues were designed and synthesised from their precursor chalcone analogues, and all these compounds were ascertained by IR, 1H NMR, and mass spectral analysis. Subsequently, all these compounds were evaluated for anticancer activities against breast cancer (MCF-7) and normal Vero (Monkey Kidney) cell lines, and five selected compounds from the series were evaluated against Hela (Human Cervical), MDA-MB-231 (Breast), and A-549 (Lung cancer) cell lines using the Sulforhodamine B (SRB) assay method. Compounds 3a, 6a, 6e, 5b, 7a, 5a, and 7d were found to be the most potent in the series, with a GI50 value of 10 to 30 M in the MCF-7 cell line. Moreover, the same compounds 6a and 7a showed remarkable cytotoxicity against the A-549 (Lung) cell line with a GI50 value ranging from 10 to 30 M, while compound 3a displayed moderate cytotoxicity against the Hela (Human Cervical) cell line. All these compounds were found nontoxic to the Vero (Monkey Kidney) normal cell line. [ABSTRACT FROM AUTHOR]

In this paper, we report the design and synthesis of 4‐substituted 7‐(3‐fluoro‐4‐methoxybenzyl)‐7H‐pyrrolo[2,3‐d]pyrimidines of scaffold 6 as anticancer agents. A total of 19 derivatives of scaffold 6 bearing a C‐4 alkoxy, dialkylamino, alkyl, vinyl, or phenyl substituent were synthesized and evaluated. Among them, compound 6q having a C‐4 ethyl group and a benzylic methyl group showed the most potent in vitro anticancer activity, inhibiting the proliferation of Hela, MDA‐MB‐231, and MDA‐MB‐426 cancer cells at submicromolar concentrations (GI50: 0.11–0.58 μM). Compound 6q arrested the cell cycle of MDA‐MB‐231 at G2/M phase, and showed in vivo activity on nude mice bearing MDA‐MB‐231 xenografts. Compound 6q has served as an anticancer lead for further optimization. [ABSTRACT FROM AUTHOR]

Two series of 3-mercapto-1,2,4-triazole derivatives containing alkoxy substituents different in size and position were synthesized and their structures were characterized by FT-IR, 1H NMR, 13C NMR spectroscopy and elemental analysis. The synthesized compounds were assessed for their antiproliferative activity against colon cancer cell line (SW480). The results indicated that the size and position of the alkoxy group significantly influenced the antiproliferative activity. The highest cancer cell growth inhibition values were observed for the compounds containing 3,4,5-trimethoxyphenyl groups in their structures (57.74, 54.14 and 60.70% at 50 μM for compounds 5a, 12b and 14, respectively). The synthesized compounds were also subjected to DPPH protocol for evaluating the antioxidant activity. The results showed that all compounds had moderate to high levels of antioxidant capacity as compared to ascorbic acid as standard, the highest free radical scavenging capacity of 75% was observed for compound 4a at 50 μM. [ABSTRACT FROM AUTHOR]

Age-progressive neurodegenerative pathologies, including Alzheimer’s disease (AD), are distinguished and diagnosed by disease-specific components of intra- or extra-cellular aggregates. Increasing evidence suggests that neuroinflammation promotes protein aggregation, and is involved in the etiology of neurological diseases. We synthesized and tested analogs of the naturally occurring tubulin-binding compound, combretastatin A-4. One such analog, PNR502, markedly reduced the quantity of Alzheimer-associated amyloid aggregates in the BRI-Aβ1–42 mouse model of AD, while blunting the ability of the pro-inflammatory cytokine IL-1β to raise levels of amyloid plaque and its protein precursors in a neuronal cell-culture model. In transgenic Caenorhabditis elegans (C. elegans) strains that express human Aβ1–42 in muscle or neurons, PNR502 rescued Aβ-induced disruption of motility (3.8-fold, P < 0.0001) or chemotaxis (1.8-fold, P < 0.05), respectively. Moreover, in C. elegans with neuronal expression of Aβ1–42, a single day of PNR502 exposure reverses the chemotaxis deficit by 54% (P < 0.01), actually exceeding the protection from longer exposure. Moreover, continuous PNR502 treatment extends nematode lifespan 23% (P ≤ 0.001). Given that PNR502 can slow, prevent, or reverse Alzheimer-like protein aggregation in human-cell-culture and animal models, and that its principal predicted and observed binding targets are proteins previously implicated in Alzheimer’s, we propose that PNR502 has therapeutic potential to inhibit cerebral Aβ1–42 aggregation and prevent or reverse neurodegeneration.

Age-progressive neurodegenerative pathologies, including Alzheimer's disease (AD), are distinguished and diagnosed by disease-specific components of intra- or extra-cellular aggregates. Increasing evidence suggests that neuroinflammation promotes protein aggregation, and is involved in the etiology of neurological diseases. We synthesized and tested analogs of the naturally occurring tubulin-binding compound, combretastatin A-4. One such analog, PNR502, markedly reduced the quantity of Alzheimer-associated amyloid aggregates in the BRI-Aβ1–42 mouse model of AD, while blunting the ability of the pro-inflammatory cytokine IL-1β to raise levels of amyloid plaque and its protein precursors in a neuronal cell-culture model. In transgenic Caenorhabditis elegans (C. elegans) strains that express human Aβ1–42 in muscle or neurons, PNR502 rescued Aβ-induced disruption of motility (3.8-fold, P < 0.0001) or chemotaxis (1.8-fold, P < 0.05), respectively. Moreover, in C. elegans with neuronal expression of Aβ1–42, a single day of PNR502 exposure reverses the chemotaxis deficit by 54% (P < 0.01), actually exceeding the protection from longer exposure. Moreover, continuous PNR502 treatment extends nematode lifespan 23% (P ≤ 0.001). Given that PNR502 can slow, prevent, or reverse Alzheimer-like protein aggregation in human-cell-culture and animal models, and that its principal predicted and observed binding targets are proteins previously implicated in Alzheimer's, we propose that PNR502 has therapeutic potential to inhibit cerebral Aβ1–42 aggregation and prevent or reverse neurodegeneration. [ABSTRACT FROM AUTHOR]

Histone deacetylases (HDACs) are a class of enzymes that are responsible for the removal of acetyl groups from the ε-N-acetyl lysine of histones, allowing histones to wrap DNA more tightly. HDACs play an essential role in many biological processes, such as gene regulation, transcription, cell proliferation, angiogenesis, migration, differentiation and metastasis, which make it an excellent target for anticancer drug discovery. The search for histone deacetylase inhibitors (HDACis) has been intensified, with numerous HDACis being discovered, and five of them have reached the market. However, currently available HDAC always suffers from several shortcomings, such as limited efficacy, drug resistance, and toxicity. Accordingly, dual-targeting HDACis have attracted much attention from academia to industry, and great advances have been achieved in this area. In this review, we summarize the progress on inhibitors with the capacity to concurrently inhibit tubulin polymerization and HDAC activity and their application in cancer treatment., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Combretastatin analogs of the antitumor agent tubuloclustin {N-[7-(adamant-2-yloxy)-7-oxoheptanoyl]-Ndeacetylcolchicine} were prepared via esterification of combretastatin by monoesters of pimelic or adipic acid with adamantan-2-ol or (adamantan-1-yl)methanol. These conjugates were stable and cytotoxic to human lung carcinoma A549 cells (EC50 ≈ 50 – 70 nM) and caused depolymerization of microtubules and slight clustering of tubulin. Tubuloclustin analogs with shortened linkers were prepared via amidation by N-deacetylcolchicine of monoesters of adipic or succinic acids with adamantan-1-ol or (adamantan-1-yl)methanol. The conjugate N-[6-(adamantyl)-6-oxohexanoyl]-N-deacetylcolchicine was more active (EC50 ≈ 4 nM) than tubuloclustin and promoted strong tubulin clusterization. All compounds induced apoptosis of A549 cells. Tests in vivo of N-[6-(adamantyl)-6-oxoheaxnoyl]-N-deacetylcolchicine on carcinoma A549 experimental models were concluded to be promising. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract To explore the application of photoremovable protecting groups (PPGs) in the field of combination chemotherapy, we designed and synthesized a photoresponsive hybrid prodrug 4 that bearing both doxorubicin (DOX) and combretastatin A4 (CA4). Light triggered drug release investigation found that DOX release was mainly accomplished by 405 nm light while CA4 release was mainly triggered by 365 nm light, i.e., prodrug 4 exhibited a quasi-sequential release behavior when a sequential light irradiation strategy was applied. Cell viability evaluation confirmed the increased cytotoxicity of prodrug 4 compared with individual drugs towards MDA-MB-231cells, indicating that a synergistic effect was achieved. [ABSTRACT FROM AUTHOR]

A library of 3,5-diaryl-1-carbothioamide-pyrazoline (5a-j), N1-phenyl sulfonyl pyrazoline (6a-e) and pyrimidine (7a) analogs of combretastatin-A4 were synthesized and evaluated for their in vitro anticancer, anti-inflammatory and antioxidant activity. Results of in vitro assay against human breast cancer cell line (MCF-7) showed several compounds endowed with significant cytotoxicity compared to the adriamycin, a standard anticancer drug. Among the compounds synthesized, 7a was found to possess significant antiproliferative activity (GI50 < 0.1 µM) against the MCF-7 cell line as good as adriamycin (GI50 < 0.1 µM) whereas, compounds 6c, 5j and 5g also displayed good cytotoxicity (GI50 = 25.3-42.6 µM). Besides this, most active compound 7a was also evaluated against human myeloid leukemia cell line K562 and the remarkable result was obtained with GI50 < 0.1 µM, comparable to that of adriamycin (GI50 < 0.1 µM). In addition, all the synthesized compounds were evaluated for their anti-inflammatory and antioxidant activity. The percent inhibition studies revealed that most of the compounds were found to possess substantial anti-inflammatory and antioxidant activities. [ABSTRACT FROM AUTHOR]

The concept of a scaffold concerns many aspects at different steps on the drug development path. In medicinal chemistry, the choice of relevant “drug-likeness” scaffold is a starting point for the design of the structure dedicated to specific molecular targets. For many years, the chemical uniqueness of the stilbene structure has inspired scientists from different fields such as chemistry, biology, pharmacy, and medicine. In this review, we present the outstanding potential of the stilbene-based derivatives. Naturally occurring stilbenes, together with powerful synthetic chemistry possibilities, may offer an excellent approach for discovering new structures and identifying their therapeutic targets. With the development of scientific tools, sophisticated equipment, and a better understanding of the disease pathogenesis at the molecular level, the stilbene scaffold has moved innovation in science. This paper mainly focuses on the stilbene-based compounds beyond resveratrol, which are particularly attractive due to their biological activity. Given the “fresh outlook” about different stilbene-based compounds starting from stilbenoids with particular regard to isorhapontigenin and methoxy- and hydroxyl- analogues, the update about the combretastatins, and the very often overlooked and underestimated benzanilide analogues, we present a new story about this remarkable structure.

It is over 50 years since the discovery of microtubules, and they have become one of the most important drug targets for anti-cancer therapies. Microtubules are predominantly composed of the protein tubulin, which contains a number of different binding sites for small-molecule drugs. There is continued interest in drug development for compounds targeting the colchicine-binding site of tubulin, termed colchicine-binding site inhibitors (CBSIs). This review highlights CBSIs discovered through diverse sources: from natural compounds, rational design, serendipitously and via high-throughput screening. We provide an update on CBSIs reported in the past three years and discuss the clinical status of CBSIs. It is likely that efforts will continue to develop CBSIs for a diverse set of cancers, and this review provides a timely update on recent developments.

The Barton-Zard reaction of nitro substituted stilbenes and chalcones with ethyl isocyanoacetate afforded 3,4-diaryl- and 4-acyl-3-arylpyrroles, respectively. 3-Arylpyrrole-2,4- dicarboxylates and 4-arylisoxazoline N-oxides were side reaction products. Antimitotic activity of target 3,4-disubstituted pyrroles was studied on a sea urchin embryo model. Pyrroles unsubstituted at positions 2 and 5 were the most active. The activity increased with the number of methoxy groups in the Ar substituent. [ABSTRACT FROM AUTHOR]

Three category of N1-phenyl pyrazoline (5a-e), N1-phenyl-sulfonyl pyrazoline (6a-e), and pyridine analogs (8a-d) of combretastatin-A4 were synthesized. The structures of compounds were verified by spectroscopic techniques. All the compounds were screened for their anticancer activity against MCF-7 cell line, antioxidant (DPPH, NO, SOR and H2O2), and anti-inflammatory activity while compounds (8a-d) additionally tested against K562 cell line. Compounds 8a and 8b showed substantial anticancer activity against MCF-7 cell line (GI50 = 5.59 and 11.70 µM), although not comparable with adriamycin (GI50 ⩽ 0.1 µM). However, none of the compound was active against the K562 cell line. Nevertheless, compound 8a displayed better cytostatic activity (TGI = 69.2 µM) than the standard drug adriamycin (TGI = 75.8 µM). Most of the compounds 5a, 5b, 5c, 5e, 6a, 6b, 6c, 6d, 6e 8a, and 8b have excellently inhibited all of the free radicals better than standard drug ascorbic acid, whereas compound 5c and 5b demonstrated significant anti-inflammatory activity comparable with diclofenac sodium, a standard anti-inflammatory drug. [ABSTRACT FROM AUTHOR]