Structure–activity relationship study of glaziovianin A against cell cycle progression and spindle formation of HeLa S3 cells

Various derivatives of glaziovianin A, an antitumor isoflavone, were synthesized, and the cytotoxicity of each against HeLa S₃ cells was investigated. Compared to glaziovianin A, the O⁷-allyl derivative was found to be more cytotoxic against HeLa S₃ cells and a more potent M-phase inhibitor.     

Discovery of O6-benzyl glaziovianin A,a potent cytotoxic substance and a potent inhibitor of α,β-tubulin polymerization

We have discovered O⁶-benzyl glaziovianin A, which showed stronger inhibition of microtubule polymerization (IC₅₀ = 2.1 μM) than known α,β-tubulin inhibitors, such as colchicine and glaziovianin A. Also, we performed competition binding experiments of O⁶-benzyl glaziovianin A and revealed that O⁶-benzyl glaziovianin A binds to the colchicine binding site with high affinity. It is interesting that glaziovianin A derivatives change their mode of action in benzylation at the O⁶ (α,β-tubulin inhibitor) or O⁷ (γ-tubulin-specific inhibitor) position.     

Translation, stability, and resistance to decapping of mRNAs containing caps substituted in the triphosphate chain with BH3, Se, and NH

Decapping is an essential step in multiple pathways of mRNA degradation. Previously, we synthesized mRNAs containing caps that were resistant to decapping, both to dissect the various pathways for mRNA degradation and to stabilize mRNA for more sustained protein expression. mRNAs containing an α-β CH₂ group are resistant to in vitro cleavage by the decapping enzyme hDcp2 but poorly translated. mRNAs containing an S substitution at the β-phosphate are well translated but only partially resistant to hDcp2. We now describe seven new cap analogs substituted at the β-phosphate with BH₃ or Se, or substituted at either the α-β or β-γ O with NH. The analogs differ in affinity for eIF4E and efficiency of in vitro incorporation into mRNA by T7 RNA polymerase. Luciferase mRNAs capped with these analogs differ in resistance to hDcp2 hydrolysis in vitro, translational efficiency in rabbit reticulocyte lysate and in HeLa cells, and stability in HeLa cells. Whereas mRNAs capped with m₂^7,2′-OGpp_SpG were previously found to have the most favorable properties of translational efficiency and stability in mammalian cells, mRNAs capped with m⁷Gpp_BH3pm⁷G are translated with the same efficiency but are more stable. Interestingly, some mRNAs exhibit a lag of up to 60 min before undergoing first-order decay (t_1/2 ≅ 25 min). Only mRNAs that are efficiently capped, resistant to decapping in vitro, and actively translated have long lag phases.     

Design,Synthesis and Anticancer Evaluation of New Substituted Thiophene-Quinoline Derivatives

A series of new isoxazolyl, triazolyl and phenyl based 3-thiophen-2-yl-quinoline derivatives were synthesized adopting click chemistry approach. In addition, the synthesis of new useful synthon, (2-chloroquinolin-3-yl) (thiophen-2-yl) methanol, is reported. The obtained compounds were characterized by spectral data analysis and evaluated for their anticancer activity. All the derivatives were subjected to in vitro MTT cytotoxicity screening assay against a panel of four different human cancer cell lines, liver (HepG-2), colon (HCT-116), human cervical cancer (HeLa) and breast (MCF-7). Out of a library of 17 compounds, two compounds have been identified as potent and selective cytotoxic agents against HeLa and MCF-7 cell lines. SAR studies for such hybridized analogues were investigated and phenyl derivatives were proved to be more potent than isoxazole and triazole derivatives. Furthermore, the promising compounds were selected for in vitro inhibition of EGFR-TK and Topo II enzymes. Also, they were subjected to cell cycle arrest analysis and apoptosis assay on MCF-7 cells. Our recent finding highlights these thiophene-quinoline analogues as a promising class of compounds for further studies concerning new anticancer therapies.     

Synthesis and SAR study of novel anticancer and antimicrobial naphthoquinone amide derivatives

A series of novel naphthoquinone amide derivatives of the bioactive quinones, plumbagin, juglone, menadione and lawsone, with various amino acids were synthesized. The compounds were characterized by ¹H NMR, ¹³C NMR, Mass, IR and elemental analysis. All the compounds were evaluated for their anticancer activity against HeLa and SAS cancer cell lines and 3D-QSAR indicated the presence of electron donating group near sulphur enhanced the activity against HeLa cells. Among the derivatives synthesized, compounds 11f, 10a, 10b and 10g were the most active with IC₅₀ values of 16, 12, 14 and 24.5 μM, respectively. The analogues were also screened for antimicrobial activity against two human bacterial pathogens, the Gram-positive Methicillin resistant Staphylococcus aureus (MRSA) and the Gram-negative Pseudomonas aeruginosa and a human yeast pathogen, Fluconazole resistant Candida albicans (FRCA). Among the synthesized compounds, 8g, 10g and 11g exhibited maximum antibacterial activity towards MRSA and antifungal activity against FRCA in well diffusion method.     

Synthesis and changes in affinity for NOP and opioid receptors of novel hexapeptides containing β2-tryptophan analogues

We report the synthesis and the biological activity of new analogues of Ac-RFMWMK-NH₂ and Ac-RYYRWK-NH₂, modified in position 4 and 5, respectively, with incorporation of newly synthesized β²-tryptophan analogues. Trp was substituted by the (S)-2-(1-methyl-1H-indol-3-yl)propionic residue or by (S)-2-(5-methoxy-1H-indol-3-yl)propionic residue. The biological activity (pEC₅₀ and E_max) of these compounds was tested on electrically stimulated preparations of rat vas deferens. The 5-methoxy β-tryptophan group reverses the affinity of the compounds.     

New indolesulfonamide derivatives targeting the colchicine site of tubulin: synthesis,anti-tumour activity,structure–activity relationships,and molecular modelling

Searching for improved indolesulfonamides with higher polarities, 45 new analogues with modifications on the sulfonamide nitrogen, the methoxyaniline, and/or the indole 3-position were synthesised. They show submicromolar to nanomolar antiproliferative IC₅₀ values against four human tumour cell lines and they are not P-glycoprotein substrates as their potencies against HeLa cells did not improve upon cotreatment with multidrug resistance (MDR) inhibitors. The compounds inhibit tubulin polymerisation in vitro and in cells, thus causing a mitotic arrest followed by apoptosis as shown by cell cycle distribution studies. Molecular modelling studies indicate binding at the colchicine site. Methylated sulfonamides were more potent than those with large and polar substitutions. Amide, formyl, or nitrile groups at the indole 3-position provided drug-like properties for reduced toxicity, with Polar Surface Areas (PSA) above a desirable 75 Ų. Nitriles 15 and 16 are potent polar analogues and represent an interesting class of new antimitotics.     

Design,synthesis and biological evaluation of 4-(pyridin-4-yloxy)benzamide derivatives bearing a 5-methylpyridazin-3(2H)-one fragment

A series of 4-(pyridin-4-yloxy)benzamide derivatives bearing a 5-methylpyridazin-3(2H)-one fragment were designed, synthesized, and evaluated for their biological activity. Most compounds showed effective inhibitory activity against cancer cell lines of A549, HeLa and MCF-7. Among them, the most promising compound 40 showed excellent activity against A549, HeLa and MCF-7 cell lines with IC₅₀ values of 1.03, 1.15 and 2.59 μM, respectively, which was 2.606.95 times more active than that of Golvatinib. The structure-activity relationships (SARs) showed that the introduction of 5-methylpyridazin-3(2H)-one to “5-atom linker” and the modification of the amide with morpholine group were beneficial for enhancing the inhibitory activity of compounds. In addition, the further research on compound 40 mainly include c-Met kinase activity, concentration dependence, apoptosis (acridine orange staining), and molecular docking.     

Syntheses of 6-(2-hydroxy-6-phenylhexyl)-5,6-dihydro-2H-pyran-2-one derivatives and their cytotoxicities

The cytotoxicities against cancer cells (HL-60, HeLa) and insect cells (Sf9) of four stereoisomers of 6-(2-hydroxy-6-phenylhexyl)− 5,6-dihydro-2H-pyran-2-one (1) were evaluated, and then their structure-activity relationships examined. The 2′-dehydroxy derivative 5 of (6 R,2′R)- and (6 R,2′S)-1 showed the highest activity against HeLa cells (IC₅₀ = 1.4 μM). To evaluate the effect of the 2′-hydroxy group of 1, 6R-and 6S-oxetane derivatives were also synthesized and their activities examined. Against HeLa and HL-60 cells, the activities of the less potent stereoisomers were enhanced 3–4-fold by the introduction of the oxetane moieties at the 2′-position. Against the insect cell line (Sf9), phenyl derivative 7 showed the highest activity with an IC₅₀ value of 8.0 μM.     

Design,synthesis, antiviral and cytostatic activity of ω-(1H-1,2,3-triazol-1-yl)(polyhydroxy)alkylphosphonates as acyclic nucleotide analogues

The efficient synthesis of a new series of polyhydroxylated dibenzyl ω-(1H-1,2,3-triazol-1-yl)alkylphosphonates as acyclic nucleotide analogues is described starting from dibenzyl ω-azido(polyhydroxy)alkylphosphonates and selected alkynes under microwave irradiation. Selected O,O-dibenzylphosphonate acyclonucleotides were transformed into the respective phosphonic acids. All compounds were evaluated in vitro for activity against a broad variety of DNA and RNA viruses and for cytostatic activity against murine leukemia L1210, human T-lymphocyte CEM and human cervix carcinoma HeLa cells. Compound (1S,2S)-16b exhibited antiviral activity against Influenza A H3N2 subtype (EC₅₀ = 20 μM—visual CPE score; EC₅₀ = 18 μM—MTS method; MCC >100 μM, CC₅₀ >100 μM) in Madin Darby canine kidney cell cultures (MDCK), and (1S,2S)-16k was active against vesicular stomatitis virus and respiratory syncytial virus in HeLa cells (EC₅₀ = 9 and 12 μM, respectively). Moreover, compound (1R,2S)-16l showed activity against both herpes simplex viruses (HSV-1, HSV-2) in HEL cell cultures (EC₅₀ = 2.9 and 4 μM, respectively) and feline herpes virus in CRFK cells (EC₅₀ = 4 μM) but at the same time it exhibited cytotoxicity toward uninfected cell (MCC ⩾ 4 μM). Several other compounds have been found to inhibit proliferation of L1210, CEM as well as HeLa cells with IC₅₀ in the 4–50 μM range. Among them compounds (1S,2S)- and (1R,2S)-16l were the most active (IC₅₀ in the 4–7 μM range).     

Thio-sugar motif of functional CARB-pharmacophore for antineoplastic activity. Part 2

Diverse functionalized representatives of (1-4)-S-thiodisaccharides, 6–9 were synthesized and assessed for cytotoxicity and apoptosis against human cancer cell lines (A549, LoVo, MCF-7 and HeLa). The FCP 6 was more active against MCF-7 cells (i.e., an estrogen-dependent breast cancer line), whereas other (1-4)-S-thiodisaccharides showed strongest activity against A549 cells (i.e., a lung adenocarcinoma line). We propose to use a concept of functional ‘CARB-pharmacophores’ when evaluating a potential for the compounds’ general antineoplastic activity. Future studies will determine the reasons for cell-type specificity of these compounds. The thio-sugar motif appears to be a promising lead for future developments.     

Design,synthesis, anti-inflammatory,cytotoxic and cell based studies of some novel side chain analogues of myrrhanones A & B isolated from the gum resin of Commiphora mukul

Myrrhanones A (1) and B (2), isolated from the gum resin of Commiphora mukul, were reported to exhibit anticancer and anti-inflammatory activities. In view of their interesting skeletal features and biological activities they have been chemically modified by exploiting their side chain functionalities to synthesise 29 diverse analogues. All the synthesized analogues were screened for their cytotoxic potential against a panel of five human cancer cell lines which include DU145 (Prostate), HT-29 (Colon), MCF-7 (Breast), Hela (Cervical) and U87MG (Glioblastoma) along with a normal cell line (L132). The synthesized analogues were also screened for anti-inflammatory activity against TNF-α and IL-1β using LPS induced inflammation model employing U937 cells. The biological screening results revealed that compounds 4b (piperidine analogue), 9d (linear aliphatic four member amide analogue) and 9i (N-methyl piperazine analogue) displayed significant cytotoxic activity against MCF-7, HT-29 and DU145 [IC₅₀ (μM): 4.65 ± 1.28, 5.48 ± 0.13 and 6.63 ± 1.39] respectively. These analogues were further taken up for apoptotic assay, which confirmed that compounds 4b, 9d and 9i induced apoptosis in MCF-7, HT-29, DU145 cells and arrested in G0/G1 phase. Further, compounds 9c and 9g found to exhibit good anti-inflammatory activity against TNF-α with IC₅₀ (μM) values of 10.02 ± 2.13 and 10.53 ± 0.48 respectively, while compound 2 exhibited strong inhibitory activity against both TNF-α (IC₅₀: 9.39 ± 0.44 μM) and IL-1β (IC₅₀: 12.15 ± 1.36 μM).     

A sensitive mass spectrum assay to characterize engineered methionine adenosyltransferases with S-alkyl methionine analogues as substrates

Methionine adenosyltransferases (MATs) catalyze the formation of S-adenosyl-l-methionine (SAM) inside living cells. Recently, S-alkyl analogues of SAM have been documented as cofactor surrogates to label novel targets of methyltransferases. However, these chemically synthesized SAM analogues are not suitable for cell-based studies because of their poor membrane permeability. This issue was recently addressed under a cellular setting through a chemoenzymatic strategy to process membrane-permeable S-alkyl analogues of methionine (SAAMs) into the SAM analogues with engineered MATs. Here we describe a general sensitive activity assay for engineered MATs by converting the reaction products into S-alkylthioadenosines, followed by high-performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS) quantification. With this assay, 40 human MAT mutants were evaluated against 7 SAAMs as potential substrates. The structure–activity relationship revealed that, besides better engaged SAAM binding by the MAT mutants (lower K_m value in contrast to native MATs), the gained activity toward the bulky SAAMs stems from their ability to maintain the desired linear S_N2 transition state (reflected by higher k_cat value). Here the I117A mutant of human MATI was identified as the most active variant for biochemical production of SAM analogues from diverse SAAMs.     

Synthesis,antimalarial activity and cytotoxic potential of new monocarbonyl analogues of curcumin

A series of novel monocarbonyl analogues of curcumin have been designed, synthesized and tested for their activity against Molt4, HeLa, PC3, DU145 and KB cancer cell lines. Six of the analogues showed potent cytotoxicity towards these cell lines with IC₅₀ values below 1 μM, which is better than doxorubicin, a US FDA approved drug. Several analogues were also found to be active against both CQ-resistant (W2 clone) and CQ-sensitive (D6) strains of Plasmodium falciparum in an in-vitro antimalarial screening. This level of activity warrants further investigation of the compounds for development as anticancer and antimalarial agents.     

Synthesis and evaluation of the cell cycle arrest and CT DNA interaction properties of 4β-amino-4′-O-demethyl-4-deoxypodophyllotoxins

A series of 4β-amino-4′-O-demethyl-4-deoxypodophyllotoxin derivatives were synthesized, and their cytotoxicities against several human cancer cell lines, including HepG2, A549, HeLa and HCT-8 cells, evaluated. Some of these compounds exhibited higher levels of cytotoxicity than the anticancer drug etoposide. 4β-N-(4-Nitrophenyl piperazinyl)-4′-O-demethyl-4-deoxypodophyllotoxin (11) was found to be the most potent synthesized compound in the current study, and induced cell cycle arrest in the G2/M phase in HeLa cells, which was accompanied by apoptosis. Furthermore, this compound activated the expression of cdc2, cyclin B1, p53 and caspase-3 in HeLa cells, leading to changes in the conformation of calf thymus DNA from the B-form to a more compact C-form.     

Design,synthesis, in vitro and in silico evaluation of anti-colorectal cancer activity of curcumin analogues containing 1,3-diphenyl-1H-pyrazole targeting EGFR tyrosine kinase

Recent studies have shown that monocarbonyl analogues of curcumin (MACs) and 1H-pyrazole heterocycle both demonstrated promising anticancer activities, in which several compounds containing these scaffolds could target EGFR. In this research, 24 curcumin analogues containing 1H-pyrazole (a1-f4) were synthesized and characterized by using modern spectroscopic techniques. Firstly, synthetic MACs were screened for cytotoxicity against human cancer cell lines such as SW480, MDA-MB-231 and A549, from which the 10 most potential cytotoxic compounds were identified and selected. Subsequently, the selected MACs were further screened for their inhibition against tyrosine kinases, which showed that a4 demonstrated the most significant inhibitory effects on EGFR^WT and EGFR^L858R. Based on the results, a4 further demonstrated its ability to cause morphological changes, to increase the percentage of apoptotic cells, and to increase caspase-3 activity, suggesting its apoptosis-inducing activity on SW480 cells. In addition, the effect of a4 on the SW480 cell cycle revealed its ability to arrest SW480 cells at G₂/M phase. In subsequent computer-based assessments, a4 was predicted to possess several promising physicochemical, pharmacokinetic, and toxicological properties. Via molecular docking and molecular dynamics simulation, a reversible binding mode between a4 and EGFR^WT, EGFR^L858R, or EGFR^G719S, remained stable within the 100-ns simulation due to effective interactions especially the hydrogen bonding with M793. Finally, free binding energy calculations suggested that a4 could inhibit the activity of EGFR^G719S more effectively than other EGFR forms. In conclusion, our work would provide the basis for the future design of promising synthetic compounds as anticancer agents targeting EGFR tyrosine kinase.     

Characterization of chlorinated valepotriates from Valeriana jatamansi

HPLC–PDA–MS and TLC analysis were used to look for minor cytotoxic chlorinated valepotriates from whole plants of Valeriana jatamansi (syn. Valeriana wallichii DC.). This resulted in isolation of 15 chlorinated valepotriates, designated as chlorovaltrates A-O, together with six known analogues, (1S,3R,5R,7S,8S,9S)-3,8-epoxy-1,5-dihydroxyvalechlorine, volvaltrate B, chlorovaltrate, rupesin B, (1S,3R,5R,7S,8S,9S)-3,8-epoxy-1-O-ethyl-5-hydroxyvalechlorine, and (1R,3R,5R,7S,8S,9S)-3,8-epoxy-1-O-ethyl-5-hydroxyvalechlorine. Their structures were elucidated by spectroscopic methods including homo- and heteronuclear two-dimensional NMR experiments. Chlorovaltrates K-N, chlorovaltrate and rupesin B showed moderate cytotoxicity against lung adenocarcinoma (A 549), metastatic prostate cancer (PC-3M), colon cancer (HCT-8) and hepatoma (Bel 7402) cell lines with IC₅₀ values of 0.89–9.76 μM.     

Synthesis,structure-activity relationship and molecular docking studies of 3-O-flavonol glycosides as cholinesterase inhibitors

The prime objective of this research work is to prepare readily soluble synthetic analogues of naturally occurring 3-O-flavonol glycosides and then investigate the influence of various substituents on biological properties of synthetic compounds. In this context, a series of varyingly substituted 3-O-flavonol glycosides have been designed, synthesized and characterized efficiently. The structures of synthetic molecules were unambiguously corroborated by IR, ¹H, ¹³C NMR and ESI-MS spectroscopic techniques. The structure of compound 22 was also analyzed by X-ray diffraction analysis. All the synthetic compounds (21–30) were evaluated for in vitro inhibitory potential against cholinesterase enzymes. The results displayed that most of the derivatives were potent inhibitors of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) with varying degree of IC₅₀ values. The experimental results were further encouraged by molecular docking studies in order to explore their binding behavior with the active pocket of AChE and BChE enzymes. The experimental and theoretical results are in parallel with one another.     

Repair of O6-methyl-guanine residues in DNA takes place by a similar mechanism in extracts from hela cells,human liver,and rat liver

Extracts from HeLa S₃ cells, human liver, and rat liver were found to contain an activity that transfers the methyl group from O⁶-methyl-guanine residues in DNA to a cysteine residue of an acceptor protein. The molecular weights of the acceptor proteins in HeLA cells and human liver are 24,000 ± 1,000 and 23,000 ± 1,000. respectively. Assuming that each acceptor molecule is used only once, the average number of acceptor molecules in HeLa cells was calculated to be about 50,000. The extracts also contained 3-methyl-adenine-DNA glycosylase activity and 7-methyl-guanine-DNA glycosylase activity, although the latter activity was not detected in extracts from human liver in our assay system. Thus, the three major alkylation products resulting from the effect of methylating agents, such as N-methyl-N-nitroso urea, can all be repaired in animal cells. Pretreatment of HeLa cells with N-methyl-N′-nitro-N-nitrosoguanidinc (0.1 μg/ml) strongly reduced the capacity of HeLa cell extracts to repair O⁶-methyl-guanine residues, while the activity of three DNA-N-glycosylases was essentially unaltered. This inactivation was not caused by a direct methylation of the enzyme by the carcinogen. The results demonstrate that the mechanism of repair of O⁶-methyl-guaninc residues, in DNA is strikingly similar in E coli and animal cells, including humans.