Design of Novel 2-Phenylquinazolin-4-amines as Selective CYP1B1 Inhibitors for Overcoming Paclitaxel Resistance in A549 Cells.

Cytochrome P450 1B1 (CYP1B1) contributes to the metabolic inactivation of chemotherapeutics when overexpressed in tumor cells. Selective inhibition of CYP1B1 holds promise for reversing drug resistance. In our pursuit of potent CYP1B1 inhibitors, we designed and synthesized a series of 2-phenylquinazolin-4-amines. A substantial proportion of these newly developed inhibitors demonstrated inhibitory activity against CYP1B1, accompanied by improved water solubility. Remarkably, compound 14b exhibited exceptional inhibitory efficacy and selectivity toward CYP1B1. Molecular docking studies suggested that the expansion of the π-system through aromatization, the introduction of an amine group, and iodine atom augmented the binding affinity. Furthermore, inhibitors 14a, 14b, and 14e demonstrated the ability to significantly reduce the resistance in A549 cells to paclitaxel, while also inhibiting the migration and invasion of these cells. Finally, radioiodine labeling experiments shed light on the metabolic pathway of compound 5l in mice, highlighting the potential of 125I-5l as a radioactive probe for future research endeavors.

Design and Synthesis of Novel Near-Infrared Fluorescence Probes Based on an Open Conformation of a Cytochrome P450 1B1 Complex for Molecular Imaging of Colorectal Tumors.

Cytochrome P450 1B1 (CYP1B1) is induced during the early stage of cancer and is universally overexpressed in tumors. Thus, it was considered as a potential biomarker for the monitoring of cancer. In this study, we designed and synthesized CYP1B1-targeted near-infrared (NIR) fluorescence molecular probes based on the latest reported open conformation of the CYP1B1-α-naphthoflavone (ANF) complex. According to the architecture of the open channel, we introduced linkers and a Cy5.5 fragment at the 5' position of ANF derivatives with strong CYP1B1 inhibitory activity to obtain probes 19-21. Then, in vitro cell-based studies showed that the probes could be enriched in tumor cells by binding to CYP1B1. During in vivo and ex vivo imaging in a xenograft mouse model, probe 19 with the best binding affinity was proven to be able to identify tumor sites in both fluorescence imaging and photoacoustic imaging modes.

Multiple machine learning, molecular docking, and ADMET screening approach for identification of selective inhibitors of CYP1B1.

Cytochrome P4501B1 is a ubiquitous family protein that is majorly overexpressed in tumors and is responsible for biotransformation-based inactivation of anti-cancer drugs. This inactivation marks the cause of resistance to chemotherapeutics. In the present study, integrated in-silico approaches were utilized to identify selective CYP1B1 inhibitors. To achieve this objective, we initially developed different machine learning models corresponding to two isoforms of the CYP1 family i.e. CYP1A1 and CYP1B1. Subsequently, small molecule databases including ChemBridge, Maybridge, and natural compound library were screened from the selected models of CYP1B1 and CYP1A1. The obtained CYP1B1 inhibitors were further subjected to molecular docking and ADMET analysis. The selectivity of the obtained hits for CYP1B1 over the other isoforms was also judged with molecular docking analysis. Finally, two hits were found to be the most stable which retained key interactions within the active site of CYP1B1 after the molecular dynamics simulations. Novel compound with CYP-D9 and CYP-14 IDs were found to be the most selective CYP1B1 inhibitors which may address the issue of resistance. Moreover, these compounds can be considered as safe agents for further cell-based and animal model studies. Communicated by Ramaswamy H. Sarma.

Novel compound heterozygous mutations in CYP1B1 identified in a Chinese family with developmental glaucoma.

Developmental glaucoma, a subset of glaucoma, is associated with trabeculodysgenesis and/or anterior segment dysgenesis. It is one of the major causes of childhood blindness. Understanding its genetic background is important to diagnose, and identify potential therapeutic targets, of this disease. The present study aimed to detect the molecular origin of developmental glaucoma in a Chinese pedigree and its association with glaucomatous phenotypes. A three­generation pedigree with developmental glaucoma was analyzed in the current study; a thorough ocular examination was performed on the proband and other individuals in the family. Genomic DNA was extracted from the peripheral blood of each individual, and possible disease­causing genes were screened for mutations using a candidate gene panel. Exons and adjacent regions of the target genes were captured and enriched by probe hybridization. The enriched genes were sequenced on an Illumina high­throughput sequencer. Variations were verified in other family members using Sanger sequencing. Disease causing mutations were analyzed by comparing the sequences and the structures of wild­type and mutated cytochrome P450 family 1 subfamily B member 1 (CYP1B1) proteins using PyMOL software. The proband was diagnosed with developmental glaucoma and his parents and other relatives were asymptomatic. Novel compound heterozygous mutations, c.3G>A (p.M1I) and c.1310C>T (p.P437L), in CYP1B1 were detected in the proband, with the former inherited from his father and the latter from his mother. The c.3G>A (p.M1I) change is a novel mutation that disrupts the ATG start codon in exon one of CYP1B1 and therefore interferes with the translation start site. In conclusion, the findings of the present study suggested that the aforementioned compound heterozygous mutations in CYP1B1 may have caused developmental glaucoma in this Chinese family. The c.3G>A mutation in CYP1B1 is a novel mutation, and this study expands the gene mutation spectrum of CYP1B1.

Perspective of structural flexibility on selective inhibition towards CYP1B1 over CYP1A1 by α-naphthoflavone analogs.

Research on action selectivity between CYP1A1 and CYP1B1 is particularly valuable for cancer chemoprevention and chemotherapy. However, they share a very close similarity in their ligand-binding pockets that α-naphthoflavone (ANF) is the co-crystal ligand for both isoforms, which poses a major challenge in revealing their selectivity mechanism. Therefore, three selective CYP1B1 inhibitors derived from ANF were selected to illustrate the structural basis for the selectivity between the two isoforms via a comprehensive computational strategy. It was found that the sustainability of the π-π stacking interactions with the phenylalanine residues of the two isoforms, namely, Phe123, Phe224, and Phe258 for CYP1A1, and Phe134, Phe231, and Phe268 for CYP1B1, played a crucial role in determining the selectivity of ligands with a classic aromatic conjugation system like ANF and its derivatives for CYP1B1 versus CYP1A1. Of note, the structural flexibility of the corresponding protein domains mainly orchestrated the sustainability of the corresponding π-π stacking interactions, thereby determining the binding selectivity. Therefore, the structure modification of naphthoflavone lead compounds into preferable binding configurations to satisfy the π-π stacking interactions of the key phenylalanine residues within CYP1B1 would be an inspiring strategy devised to improve the inhibitory selectivity towards CYP1B1. Collectively, this study revealed valuable insight into understanding the selective mechanism between CYP1A1 and CYP1B1 from the perspective of structural flexibility, which sheds light on the future rational design of CYP1B1 selective inhibitors.

Structure of an ancestral mammalian family 1B1 cytochrome P450 with increased thermostability.

Mammalian cytochrome P450 enzymes often metabolize many pharmaceuticals and other xenobiotics, a feature that is valuable in a biotechnology setting. However, extant P450 enzymes are typically relatively unstable, with T50 values of ∼30-40 °C. Reconstructed ancestral cytochrome P450 enzymes tend to have variable substrate selectivity compared with related extant forms, but they also have higher thermostability and therefore may be excellent tools for commercial biosynthesis of important intermediates, final drug molecules, or drug metabolites. The mammalian ancestor of the cytochrome P450 1B subfamily was herein characterized structurally and functionally, revealing differences from the extant human CYP1B1 in ligand binding, metabolism, and potential molecular contributors to its thermostability. Whereas extant human CYP1B1 has one molecule of α-naphthoflavone in a closed active site, we observed that subtle amino acid substitutions outside the active site in the ancestor CYP1B enzyme yielded an open active site with four ligand copies. A structure of the ancestor with 17ß-estradiol revealed only one molecule in the active site, which still had the same open conformation. Detailed comparisons between the extant and ancestor forms revealed increases in electrostatic and aromatic interactions between distinct secondary structure elements in the ancestral forms that may contribute to their thermostability. To the best of our knowledge, this represents the first structural evaluation of a reconstructed ancestral cytochrome P450, revealing key features that appear to contribute to its thermostability.

Carvedilol serves as a novel CYP1B1 inhibitor, a systematic drug repurposing approach through structure-based virtual screening and experimental verification.

Cytochrome P450 1B1 (CYP1B1) is a promising target for prevention and therapy of cancer, particularly those with drug resistance, stimulating cancer cell survival, and promoting cancer resistance. In view of the extreme complexity and high risk in drug discovery and development, a drug repurposing strategy was applied in the present study to find potential CYP1B1 inhibitors through structure-based virtual screening in the FDA database. Intriguingly, after a thorough assessment of docking scores, binding affinities, as well as binding modes, six compounds were highlighted for further verification. In fact, both carvedilol and indacaterol showed inhibitory activity towards human CYP1B1 with the IC50 of 1.11 µM and 59.52 µM, respectively, according to EROD assay; however, neither docking score nor the detailed binding mode of carvedilol in the hit pose dictated to be a superior CYP1B1 inhibitor to indacaterol, which called for the necessity to re-access the binding mode of carvedilol. Thus, the top two representative docking poses of carvedilol were re-assessed. Indeed, compared to the one hit in the virtual screening (due to a false positive Glide gscore), the other docking pose exhibited ideal performance in both molecular dynamics (MD) simulation, binding free energy, and density functional theory (DFT) calculation evaluations. This identification of the exact binding pose of carvedilol is not only essential for a better understanding of the mechanism underlying its activity, but also contributes to uncovering the structure-activity relationship of CYP1B1 inhibitors. Of note, carvedilol exhibited direct cytotoxicity against both human lung adenocarcinoma epithelial cell line A459 and its Taxol-resistant subline (A549/Taxol). In particular, it showed superior toxicity towards A549/Taxol cells that overexpressed CYP1B1, which further supported its potential to be an effective CYP1B1 inhibitor.

Carcinogenic Metabolic Activation Process of Naphthalene by the Cytochrome P450 Enzyme 1B1: A Computational Study.

The metabolic activation and transformation of naphthalene by the cytochrome P450 enzyme (CYP 1B1) plays an important role in its potential carcinogenicity. The process has been explored by a quantum mechanics/molecular mechanics (QM/MM) computational method. Molecular dynamic simulations were performed to explore the interaction between naphthalene and CYP 1B1. Naphthalene involves α- and ß-carbon, the electrophilic addition of which would result in different reaction pathways. Our computational results show that both additions on α- and ß-carbon can generate naphthalene 1,2-oxide. The activation barrier for the addition on ß-carbon is higher than that for the α-carbon by 2.6 kcal·mol-1, which is possibly caused by the proximity between ß-carbon and the iron-oxo group of Cpd I in the system. We also found that naphthalene 1,2-oxide is unstable and the O-C bond cleavage easily occurs via cellular hydronium ion, hydroxyl radical/anion; then it will convert to the potential ultimate carcinogen 1,2-naphthoquinone. The results demonstrate and inform a detailed process of generating naphthalene 1,2-oxide and new predictions for its conversion.

CYP enzymes, expressed within live human suspension cells, are superior to widely-used microsomal enzymes in identifying potent CYP1A1/CYP1B1 inhibitors: Identification of quinazolinones as CYP1A1/CYP1B1 inhibitors that efficiently reverse B[a]P toxicity and cisplatin resistance.

Microsomal cytochrome P450 (CYP) enzymes, isolated from recombinant bacterial/insect/yeast cells, are extensively used for drug metabolism studies. However, they may not always portray how a developmental drug would behave in human cells with intact intracellular transport mechanisms. This study emphasizes the usefulness of human HEK293 kidney cells, grown in 'suspension' for expression of CYPs, in finding potent CYP1A1/CYP1B1 inhibitors, as possible anticancer agents. With live cell-based assays, quinazolinones 9i/9b were found to be selective CYP1A1/CYP1B1 inhibitors with IC50 values of 30/21 nM, and > 150-fold selectivity over CYP2/3 enzymes, whereas they were far less active using commercially-available CYP1A1/CYP1B1 microsomal enzymes (IC50, >10/1.3-1.7 µM). Compound 9i prevented CYP1A1-mediated benzo[a]pyrene-toxicity in normal fibroblasts whereas 9b completely reversed cisplatin resistance in PC-3/prostate, COR-L23/lung, MIAPaCa-2/pancreatic and LS174T/colon cancer cells, underlining the human-cell-assays' potential. Our results indicate that the most potent CYP1A1/CYP1B1 inhibitors would not have been identified if one had relied merely on microsomal enzymes.

Is CYP1B1 involved in the metabolism of dioxins in the pig?

2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is the most difficult to biodegradate and the most toxic dioxin congener. Previously, we demonstrated in silico the ability of pig CYP1A1 to hydroxylate 2,7-dichlorodibenzo-p-dioxin (DiCDD), but not TCDD. To increase our knowledge concerning the low effectiveness of TCDD biodegradability, we analyzed in silico the binding selectivity and affinity between pig CYP1B1 and the two dioxins by means of molecular modeling. We also compared the effects of TCDD and DiCDD on CYP1B1 gene expression (qRT-PCR) and catalytic (EROD) activity in porcine granulosa cells. It was found that DiCDD and TCDD were stabilized within the pig CYP1B1 active site by hydrophobic interactions. The analysis of substrate channel availability revealed that both dioxins opened the exit channel S, allowing metabolites to leave the enzyme active site. Moreover, DiCDD and TCDD increased the CYP1B1 gene expression and catalytic activity in porcine granulosa cells. On the other hand, TCDD demonstrated higher than DiCDD calculated affinity to pig CYP1B1, hindering TCDD exit from the active site. The great distance between CYP1B1's heme and TCDD also might contribute to the lower hydroxylation effectiveness of TCDD compared to that of DiCDD. Moreover, the narrow active site of pig CYP1B1 may immobilize TCDD molecule, inhibiting its hydroxylation. The results of the access channel analysis and the distance from pig CYP1B1's heme to TCDD suggest that the metabolizing potential of pig CYP1B1 is higher than that of pig CYP1A1. However, this potential is probably not sufficiently high to considerably improve the slow TCDD biodegradation.

Design and synthesis of selective CYP1B1 inhibitor via dearomatization of α-naphthoflavone.

Selective cytochrome P450 (CYP) 1B1 inhibition has potential as an anticancer strategy that is unrepresented in the current clinical arena. For development of a selective inhibitor, we focused on the complexity caused by sp3-hybridized carbons and synthesized a series of benzo[h]chromone derivatives linked to a non-aromatic B-ring using α-naphthoflavone (ANF) as the lead compound. Ring structure comparison suggested compound 37 as a suitable cyclohexyl-core with improved solubility. Structural evolution of 37 produced the azide-containing cis-49a, which had good properties in three important respects: (1) selectivity for CYP1B1 over CYP1A1 and CYP1A2 (120-times and 150-times, respectively), (2) greater inhibitory potency of >2 times that of ANF, and (3) improved solubility. The corresponding aromatic B-ring compound 59a showed low selectivity and poor solubility. To elucidate the binding mode, we performed X-ray crystal structure analysis, which revealed the interaction mode and explained the subtype selectivity of cis-49a.

Design, Synthesis, and Biological Evaluation of Cytochrome P450 1B1 Targeted Molecular Imaging Probes for Colorectal Tumor Detection.

Cytochrome P450 1B1 (CYP1B1) was found to be universally expressed in various tumors. Herein, we reported near-infrared fluorescent imaging probes for tumor detection via visualizing CYP1B1. After introducing the linker to a CYP1B1 selective inhibitor we found previously, we got the resulting compound 5b which kept strong inhibition ability against CYP1B1 (IC50 = 8.7 ± 1.2 nM) and high selectivity. Then, in vitro microscope studies and cell binding assay of probes indicated that the corresponding probe 6b could specifically be accumulated in CYP1B1 overexpressed colorectal cancer cell HCT-15 and showed satisfying binding affinity to target. During the in vivo noninvasive optical imaging, 6b was proved to rapidly lighten tumor in vivo as early as 6 h after injection. This work is the first attempt to visualize CYP1B1 for noninvasive imaging of tumor which could provide new approach for tumor diagnosis.

Targeting Cytochrome P450 (CYP) 1B1 Enzyme with Four Series of A-Ring Substituted Estrane Derivatives: Design, Synthesis, Inhibitory Activity, and Selectivity.

Cytochrome P450 (CYP) 1B1 is involved in the bioactivation of procarcinogens and drug resistance. To obtain selective CYP1B1 inhibitors over CYP1A1, we synthesized four series of estrane derivatives: (1) 12 estrone (E1)- and 17ß-estradiol (E2)-derivatives bearing a 3- or a 4-pyridinyl core at C2, C3, or C4, (2) eight estrane derivatives with different sulfur groups at C3, (3) 19 E1- and E2-derivatives bearing distinct aryls at C2, and (4) five D-ring derivatives. E2-derivatives were more active than oxidized E1-analogues, thus highlighting the key role of 17ß-OH for interaction with CYP1B1. 2-(4-Fluorophenyl)-E2 was the best CYP1B1 inhibitor (IC50 = 0.24 µM), with a selectivity index (SI) of 20 over CYP1A1. Furthermore, the addition of a C17α-ethynyl group as D-ring modification improved the selectivity index to 25 with only a slight loss of activity (IC50 = 0.37 µM). Our docking results showed that these compounds fit better into the CYP1B1 binding site than that of CYP1A1.

Bioinformatics analysis of CYP1B1 mutation hotspots in Chinese primary congenital glaucoma patients.

Primary congenital glaucoma (PCG) is an inherited blinding eye disease. The CYP1B1 gene was identified as a causal gene for PCG, and many mutations have been found, but no studies have focussed on the molecular epidemiology of CYP1B1 in Chinese populations. We aimed to explore the CYP1B1 mutation hotspots in Chinese PCG patients and the possible impact of these mutations on the protein structure and function. First, we performed a meta-analysis on seven datasets of Chinese populations and found L107V and R390H to be the most common CYP1B1 mutations with allele frequencies of 3.19% and 3.09%, respectively. Then, a series of bioinformatics tools were applied to determine the sequence conservative properties, model the 3D structures, and study the dynamics changes. L107 and R390 are highly conserved residues in close proximity to the hemoglobin-binding region and the active site cavity (ASC), respectively. The mutations changed the distribution of hydrogen bonds and the local electrostatic potential. Long-term molecular dynamics (MD) simulations demonstrated the destabilization of the mutant proteins, especially at the ASC, whose solvent-accessible surface areas (SASAs) were significantly decreased. Compared with the wild-type (WT) protein, the overall structures of the mutants are associated with subtle but significant changes, and the ASC seems to adopt such structures that are not able to perform the WT-like functionality. Therefore, L107V and R390H might be the most important pathogenic mutations in Chinese PCG patients.

The citrus flavonone hesperetin attenuates the nuclear translocation of aryl hydrocarbon receptor.

The environmental polycyclic aromatic hydrocarbons (PAH) and dioxins are carcinogens and their adverse effects have been largely attributed to the activation of AhR. Hesperetin is a flavonone found abundantly in citrus fruits and has been shown to be a biologically active agent. In the present study, the effect of hesperetin on the nuclear translocation of AhR and the downstream gene expression was investigated in MCF-7 cells. Confocal microscopy indicated that 7, 12-dimethylbenz[α]anthracene (DMBA) or 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) -induced nuclear translocation of AhR was deterred by hesperetin treatment. The reduced nuclear translocation could also be observed in Western analysis. Reporter-gene assay further illustrated that the induced XRE transactivation was weakened by the treatment of hesperetin. Quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) assay demonstrated that the gene expressions of CYP1A1, 1A2, and 1B1 followed the same pattern of AhR translocation. These results suggested that hesperetin counteracted AhR transactivation and suppressed the downstream gene expression.

Detection of mutations in MYOC, OPTN, NTF4, WDR36 and CYP1B1 in Chinese juvenile onset open-angle glaucoma using exome sequencing.

Juvenile onset open-angle glaucoma (JOAG) affects patients before 40 years of age, causing high intraocular pressure and severe optic nerve damage. To expand the mutation spectrum of the causative genes in JOAG, with a view to identify novel disease-causing mutations, we investigated MYOC, OPTN, NTF4, WDR36 and CYP1B1 in a cohort of 67 unrelated Chinese JOAG patients. Whole exome sequencing was used to identify possible pathogenic mutations, which were further excluded in normal controls. After sequencing and the use of a database pipeline, as well as predictive assessment filtering, we identified a total of six mutations in three genes, MYOC, OPTN and CYP1B1. Among them, 2 heterozygous mutations in MYOC (c. 1109C > T, p. (P370L); c. 1150G > C, p. (D384H)), 2 heterozygous mutations in OPTN (c. 985A > G, p.(R329G); c. 1481T > G, p. (L494W)) and 2 homozygous mutations in CYP1B1 (c. 1412T > G, p.(I471S); c. 1169G > A, p.(R390H)) were identified as potentially causative mutations. No mutation was detected in NTF4 or WDR36. Our results enrich the mutation spectra and frequencies of MYOC, OPTN and CYP1B1 in JOAG among the Chinese population. Further studies are needed to address the pathogenicity of each of the mutations detected in this study.

Oxidation of 1-chloropyrene by human CYP1 family and CYP2A subfamily cytochrome P450 enzymes: catalytic roles of two CYP1B1 and five CYP2A13 allelic variants.

1. 1-Chloropyrene, one of the major chlorinated polycyclic aromatic hydrocarbon contaminants, was incubated with human cytochrome P450 (P450 or CYP) enzymes including CYP1A1, 1A2, 1B1, 2A6, 2A13, 2B6, 2C9, 2D6, 2E1, 3A4 and 3A5. Catalytic differences in 1-chloropyrene oxidation by polymorphic two CYP1B1 and five CYP2A13 allelic variants were also examined. 2. CYP1A1 oxidized 1-chloropyrene at the 6- and 8-positions more actively than at the 3-position, while both CYP1B1.1 and 1B1.3 preferentially catalyzed 6-hydroxylation. 3. Five CYP2A13 allelic variants oxidized 8-hydroxylation much more than 6- and 3-hydroxylation, and the variant CYP2A13.3 was found to slowly catalyze these reactions with a lower kcat value than other CYP2A13.1 variants. 4. CYP2A6 catalyzed 1-chloropyrene 6-hydroxylation at a higher rate than the CYP2A13 enzymes, but the rate was lower than the CYP1A1 and 1B1 variants. Other human P450 enzymes had low activities towards 1-chloropyrene. 5. Molecular docking analysis suggested differences in the interaction of 1-chloropyrene with active sites of CYP1 and 2 A enzymes. In addition, a naturally occurring Thr134 insertion in CYP2A13.3 was found to affect the orientation of Asn297 in the I-helix in interacting with 1-chloropyrene (and also 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone, NNK) and caused changes in the active site of CYP2A13.3 as compared with CYP2A13.1.

DNA damage by 2,3,7,8-tetrachlorodibenzo-p-dioxin-induced p53-mediated apoptosis through activation of cytochrome P450/aryl hydrocarbon receptor.

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD; polycyclic aromatic hydrocarbon) is a persistent and ubiquitous environmental contaminant that causes a wide variety of deleterious effects. In this study, the DNA damage and apoptotic activity induced by TCDD was examined using in silico and in vitro approaches. In silico study showed that conformational changes and energies involved in the binding of TCDD to cytochrome P450 1B1 (CYP1B1) were crucial for its target proteins. Moreover, activated TCDD had high affinity to bind with aryl hydrocarbon receptor (AhR), with a binding energy of -564.7 Kcal/mol. Further, TCDD-CYP1B1 complex showed strong binding affinity for caspase 3, showing a binding energy of -518.5 Kcal/mol, and the docking of caspase inhibitors in the complex showed weak interaction with low binding energy as compared to TCDD-CYP1B1 caspase complexes. Interestingly, TCDD-induced apoptosis was significantly suppressed in Ac-DEVD-CMK-pretreated cells. The DNA damage activity of TCDD was quantified by comet tail formation and γ-H2AX foci formation in HaCaT cells. The role of CYP1B1 and AhR in DNA damage and apoptosis was demonstrated, and clotrimazole as well as knockdown of CYP1B1 and AhR could inhibit TCDD activation and suppress DNA damage followed by apoptosis in HaCaT cells. Moreover, TCDD increased expression of p53 and PUMA and our data showed that TCDD induced DNA damage followed by p53-mediated apoptosis. This study highlights the critical role of CYP1B1 and AhR in TCDD activity and proposes that inhibition of these key molecules might serve as a potential therapeutic approach for treatment of allergy and cancer.

Synthesis, biological evaluation and docking studies of trans-stilbene methylthio derivatives as cytochromes P450 family 1 inhibitors.

Cytochromes P450 family 1 (CYP1) are responsible for the metabolism of procarcinogens, for example polycyclic aromatic hydrocarbons and aromatic and heterocyclic amines. The inhibition of CYP1 activity is examined in terms of chemoprevention and cancer chemotherapy. We designed and synthesized a series of trans-stilbene derivatives possessing a combination of methoxy and methylthio functional groups attached in different positions to the trans-stilbene skeleton. We determined the effects of synthesized compounds on the activities of human recombinant CYP1A1, CYP1A2 and CYP1B1 and, to explain the variation of inhibitory potency of methoxystilbene derivatives and their methylthio analogues, we employed computational analysis. The compounds were docked to CYP1A1, CYP1A2 and CYP1B1 binding sites with the use of Accelrys Discovery Studio 4.0 by the CDOCKER procedure. For CYP1A2 and CYP1B1, values of scoring functions correlated well with inhibitory potency of stilbene derivatives. All compounds were relatively poor inhibitors of CYP1A2 that possess the most narrow and flat enzyme cavity among CYP1s. For the most active CYP1A1 inhibitor, 2-methoxy-4'-methylthio-trans-stilbene, a high number of molecular interactions was observed, although the interaction energies were not distinctive.

Synthesis, Anti-Breast Cancer Activity, and Molecular Docking Study of a New Group of Acetylenic Quinolinesulfonamide Derivatives.

In this study, a series of regioisomeric acetylenic sulfamoylquinolines are designed, synthesized, and tested in vitro for their antiproliferative activity against three human breast cacer cell lines (T47D, MCF-7, and MDA-MB-231) and a human normal fibroblast (HFF-1) by 4-[3-(4-iodophenyl)-2-(4-nitrophenyl)-2H-5-tetrazolio]-1,3-benzene disulfonate (WST-1) assay. The antiproliferative activity of the tested acetylenic quinolinesulfonamides is comparable to that of cisplatin. The bioassay results demonstrate that most of the tested compounds show potent antitumor activities, and that some compounds exhibit better effects than the positive control cisplatin against various cancer cell lines. Among these compounds, 4-(3-propynylthio)-7-[N-methyl-N-(3-propynyl)sulfamoyl]quinoline shows significant antiprolierative activity against T47D cells with IC50 values of 0.07 µM. In addition, 2-(3-Propynylthio)-6-[N-methyl-N-(3-propynyl)sulfa-moyl]quinoline and 2-(3-propynylseleno)-6-[N-methyl-N-(3-propynyl)sulfamoyl]quinoline display highly effective atitumor activity against MDA-MB-231 cells, with IC50 values of 0.09 and 0.50 µM, respectively. Furthermore, most of the tested compounds show a weak cytotoxic effect against the normal HFF-1 cell line. Additionally, in order to suggest a mechanism of action for their activity, all compounds are docked into the binding site of two human cytochrome P450 (CYP) isoenzymes. These data indicate that some of the title compounds display significant cytotoxic activity, possibly targeting the CYPs pathways.