341. Facile Generation of Tumor-pH-Labile Linkage-Bridged Block Copolymers for Chemotherapeutic Delivery.
作者: Chun-Yang Sun.;Yang Liu.;Jin-Zhi Du.;Zhi-Ting Cao.;Cong-Fei Xu.;Jun Wang.
来源: Angew Chem Int Ed Engl. 2016年55卷3期1010-4页
Successful bench-to-bedside translation of nanomedicine relies heavily on the development of nanocarriers with superior therapeutic efficacy and high biocompatibility. However, the optimal strategy for improving one aspect often conflicts with the other. Herein, we report a tactic of designing tumor-pH-labile linkage-bridged copolymers of clinically validated poly(D,L-lactide) and poly(ethylene glycol) (PEG-Dlink(m)-PDLLA) for safe and effective drug delivery. Upon arriving at the tumor site, PEG-Dlink(m)-PDLLA nanoparticles will lose the PEG layer and increase zeta potential by responding to tumor acidity, which significantly enhances cellular uptake and improves the in vivo tumor inhibition rate to 78.1% in comparison to 47.8% of the non-responsive control. Furthermore, PEG-Dlink(m)-PDLLA nanoparticles show comparable biocompatibility with the clinically used PEG-b-PDLLA micelle. The improved therapeutic efficacy and safety demonstrate great promise for our strategy in future translational studies.
342. Baicalein Inhibits MCF-7 Cell Proliferation In Vitro, Induces Radiosensitivity, and Inhibits Hypoxia Inducible Factor.
Hypoxia inducible factor (HIF) is a key transcription factor responsible for imparting adaptability to the cancer cells growing in tumors. HIF induces the modulation of glucose metabolism, angiogenesis, and prosurvival signaling. Therefore, HIF is one of the attractive targets to treat solid tumors. Results presented in this study indicate that Baicalein (BA) inhibits HIF stabilization and also reduces its transcription activity in MCF-7 cells in vitro. Furthermore, BA was found to have antiproliferative ability as determined by the MTT assay and clonogenic survival. BA also induces apoptosis in MCF-7 cells at the concentration of 50 µM. We also report the radiosensitization of MCF-7 cells when they are treated with BA, resulting in higher γ-radiation-induced DNA damage. BA is extensively used in Chinese medicine and is known to be nontoxic at pharmacological doses. Our studies indicate that BA is one of the attractive natural compounds suitable for further evaluation as an adjuvant therapy.
343. Antitumor and Immunomodulating Activities of Exopolysaccharide Produced by Big Cup Culinary- Medicinal Mushroom Clitocybe maxima (Higher Basidiomycetes) in Liquid Submerged Culture.
作者: Shu-Hui Hu.;Peter Chi Keung Cheung.;Raw-Pou Hung.;Yu-Kuei Chen.;Jinn-Chyi Wang.;Sue-Joan Chang.
来源: Int J Med Mushrooms. 2015年17卷9期891-901页
Water-soluble polysaccharides extracted from mushrooms have been found to have some physiological effects. In this study, exopolysaccharides (EPSs) were extracted by alcohol precipitation from cultivated broth of the mushroom Clitocybe maxima. EPSs with molecular weights of 10(4) and 10(5) Da were obtained by ultrafiltration; they are referred to as EPA and EPB, respectively. The major components of these EPSs were glucose, galactose, mannose, rhamnose, and arabinose. ICR mice with artificially induced metastatic pulmonary tumors were fed a daily diet containing EPA or EPB at doses of 8, 20, or 50 mg/kg. Results showed that the proliferation of pulmonary sarcoma lesions was lower in the groups fed EPS. In addition, the numbers of total T cells, CD4+ cells, CD8+ cells, and macrophages significantly increased in EPS-fed mice compared with the negative control group. The antitumor and immunomodulating effects observed in the EPB-fed groups were higher than those of EPA-fed groups. These results demonstrate the ability of EPSs of C. maxima to inhibit tumor cells while enhancing immune response.
344. Novel Bioactive Wild Medicinal Mushroom--Xylaria sp. R006 (Ascomycetes) against Multidrug Resistant Human Bacterial Pathogens and Human Cancer Cell Lines.
作者: Veluchamy Ramesh.;Karnewar Santosh.;Thangarajan Durai Anand.;Vellasamy Shanmugaiah.;Srigiridhar Kotamraju.;Chandran Karunakaran.;Ayyappan Rajendran.
来源: Int J Med Mushrooms. 2015年17卷10期1005-17页
In the present study, the fruiting body extracts of Xylaria sp. strain R006 were obtained from hexane, ethyl acetate and methanol. Among them, the ethyl acetate extract exhibited significant antimicrobial activities against bacterial and fungal pathogens. Based on the effective antimicrobial activity, the crude ethyl acetate extract was fractionized by two-step siliga gel column chromatography. All the fractions were tested for antibacterial activity against drug resistant Staphylococcus aureus strains (1-10) and Pseudomonas aeruginosa strains (1-8). The fraction E showed a maximum inhibition zone of 27.9 mm against drug resistant S. aureus strain 3 and 29.4 mm against drug resistant P. aeruginosa strain 4. Minimal inhibitory concentration of fraction E showed potential result against all the drug resistant strains however, the lowest concentration of 75 µg/mL-1 was observed against S. aureus strains 1 and 6 and P. aeruginosa strain 3. Further, 60 µg/mL of fraction E had significant cytotoxic activity of 54.9, 55.1 and 54.9% against MDA-MB-231 (breast carcinoma cells), A-549 (lung carcinoma cells) and MCF-7 (breast carcinoma cells) human cancer cell lines, respectively. The spectral data revealed that the fraction E has chromophoric groups in it and had the C = O stretching, C-C = C asymmetric stretch, N-H stretch and C-O stretch as functional groups. The results indicate that the metabolites of fruiting bodies of Xylaria sp. R006 are the potential natural source for the development of new anticancer agents.
345. Identification of benzothiophene amides as potent inhibitors of human nicotinamide phosphoribosyltransferase.
作者: Wei Chen.;Guoqiang Dong.;Shipeng He.;Tianying Xu.;Xia Wang.;Na Liu.;Wannian Zhang.;Chaoyu Miao.;Chunquan Sheng.
来源: Bioorg Med Chem Lett. 2016年26卷3期765-768页
Nicotinamide phosphoribosyltransferase (Nampt) is an attractive therapeutic target for cancer. A Nampt inhibitor with novel benzothiophene scaffold was discovered by high throughput screening. Herein the structure-activity relationship of the benzothiophene Nampt inhibitor was investigated. Several new inhibitors demonstrated potent activity in both biochemical and cell-based assays. In particular, compound 16b showed good Nampt inhibitory activity (IC50=0.17 μM) and in vitro antitumor activity (IC50=3.9 μM, HepG2 cancer cell line). Further investigation indicated that compound 16b could efficiently induce cancer cell apoptosis. Our findings provided a good starting point for the discovery of novel antitumor agents.
346. Expanding the structural diversity of diarylureas as multi-target tyrosine kinase inhibitors.
作者: Yuanyuan Shan.;Chen Wang.;Lin Zhang.;Jinfeng Wang.;Maoyi Wang.;Yalin Dong.
来源: Bioorg Med Chem. 2016年24卷4期750-8页
Recently approved multi-target inhibitors of receptor tyrosine kinases (RTKs) have significantly improved the clinical treatment of cancers. A series of N,N'-diarylureas incorporated with aromatic heterocycle have been designed, synthesized and evaluated as novel multi-target RTK inhibitors. The preliminary biological evaluation indicated that several compounds exhibited comparable potency with Sorafenib. Among them, compound 6f was identified as the most potent multikinase inhibitor of EGFR, KDR and FGFR1 with IC50 values of 14.83nM, 21.57nM, and 28.23nM, respectively. These compounds expanded the structural diversity of diarylureas as RTK inhibitors. The results demonstrated that compound 6f could be served as novel lead compound for further development of multi-target RTK inhibitors.
347. Metastasized Leydig cell tumor in a dog.
We present the clinical findings, diagnosis and treatment of an 11-year old intact male Fox Terrier with a malignant Leydig cell tumor of the right testicle, which metastasized to the skeletal musculature of the left hind limb. The primary tumor and the metastasis were resected with narrow margins. The dog was treated with metronomic chemotherapy using thalidomid and dyclophosphamide. Local recurrence at the site of the metastasis and a pulmonary metastasis were present 30 months after surgery. The dog was euthanized.
348. Goniothalamin induces cell cycle arrest and apoptosis in H400 human oral squamous cell carcinoma: A caspase-dependent mitochondrial-mediated pathway with downregulation of NF-κβ.
作者: Lim K Li.;Ali-Saeed Rola.;Fahme A Kaid.;Abdul Manaf Ali.;Aied M Alabsi.
来源: Arch Oral Biol. 2016年64卷28-38页
Goniothalamin is a natural occurring styryl-lactone compound isolated from Goniothalamus macrophyllus. It had been demonstrated to process promising anticancer activity on various cancer cell lines. However, little study has been carried out on oral cancer. The aim of this study was to determine the cytotoxic effects of goniothalamin against H400 oral cancer cells and its underlying molecular pathways. Results from MTT assay demonstrated that goniothalamin exhibited selective cytotoxicity as well as inhibited cells growth of H400 in dose and time-dependent manner. This was achieved primarily via apoptosis where apoptotic bodies and membrane blebbing were observed using AO/PI and DAPI/Annexin V-FITC fluorescence double staining. In order to understand the apoptosis mechanisms induced by goniothalamin, apoptosis assessment based on mitochondrial membrane potential assay and cytochrome c enzyme-linked immunosorbent assay were carried out. Results demonstrated that the depolarization of mitochondrial transmembrane potential facilitated the release of mitochondrial cytochrome c into cytosol. Caspases assays revealed the activation of initiator caspase-9 and executioner caspase-3/7 in dose-dependent manners. This form of apoptosis was closely associated with the regulation on Bcl-2 family proteins, cell cycle arrest at S phase and inhibition of NF-κβ translocation from cytoplasm to nucleus. Conclusion, goniothalamin has the potential to act as an anticancer agent against human oral squamous cell carcinoma (H400 cells).
349. A study of the synergistic effect of folate-decorated polymeric micelles incorporating Hydroxycamptothecin with radiotherapy on xenografted human cervical carcinoma.
作者: Hong You.;ShaoZhi Fu.;XingHu Qin.;YanXin Yu.;Bo Yang.;GuangPeng Zhang.;XiaoYang Sun.;Yue Feng.;Yue Chen.;JingBo Wu.
来源: Colloids Surf B Biointerfaces. 2016年140卷150-160页
In this study, Hydroxycamptothecin (HCPT)-loaded micelles were formed in water by the self-assembly of folate (FA)-decorated amphiphilic block copolymer, methoxy poly(ethylene glycol)-poly(ε-caprolactone) (MPEG-PCL), and achieved a hydrodynamic diameter about of 132 nm. HCPT release from the micelles exhibited no initial burst but showed a sustained release profile. The cytotoxicity and targeting ability of FA conjugated polymeric micelles was investigated by using methylthiazoletetrazolium (MTT) and fluorescence microscopy. We found that FA-conjugated micelles had superior cytotoxicity against HeLa cells compared to non-conjugated micelles, and that they exerted this effect by folate receptor (FR)-mediated endocytosis. In addition, HeLa cells were xenografted into nude mice and subjected to radiotherapy (RT) and/or HCPT-loaded micelle treatment. The antitumor efficacy was detected by analysis of tumor growth delay (TGD) and median survival time. Micro fluorine-18-deoxyglucose PET/computed tomography ((18)F-FDG PET/CT) was performed to assess early tumor response to HCPT-loaded micelles in combination with RT. Analysis of cell cycle redistribution, apoptosis and expression of histone H2AX phosphorylation (λ-H2AX) was used to evaluate the mechanism by which HCPT loaded micelles led to radiosensitization. Taken together, the results showed that HCPT-loaded FA decorated micelles efficiently sensitized xenografts in mice to RT, and induced G2/M phase arrest, apoptosis and expression of λ-H2AX.
350. The influence of royal jelly and human interferon-alpha (HuIFN-αN3) on proliferation, glutathione level and lipid peroxidation in human colorectal adenocarcinoma cells in vitro.
作者: Bratko Filipič.;Lidija Gradišnik.;Klemen Rihar.;Eugen Šooš.;Adriana Pereyra.;Jana Potokar.
来源: Arh Hig Rada Toksikol. 2015年66卷4期269-74页
Among royal jelly's (RJ) various biological activities, its possible antitumour activity deserves particular attention. The purpose of this study was to investigate the influence of RJ, its bioactive component 10-hydroxy-2-decenoic acid (10- HDA), and human interferon-alpha (HuIFN-αN3) on the proliferation of human colorectal adenocarcinoma cells (CaCo- 2), and ascertain their effect on intracellular glutathione (GSH) level and lipid peroxidation. We studied the antiproliferative (AP) activity of RJ [(0.1 g/10 mL phosphate buffer saline (PBS)], HuIFN-αN3 (1000 I.U. mL⁻¹), 10-HDA at 100.0 μmol L⁻¹, and their different combinations, in the ratio 1:1, 1:2, and 2:1 on CaCo-2 cells. The GSH level was measured by glutathione assay. The lipid peroxidation was measured by malondialdehyde (MDA) assay. Single RJ had a low AP activity: 2.0 (0.5 mg mL⁻¹). HuIFN-αN3 had an AP activity of 2.5 (208.33 I.U. mL⁻¹), while 10-HDA had an AP activity of 1.5 (37.5 μmol mL⁻¹). The highest AP activity of 3.8 was obtained when RJ and HuIFN-αN3 were applied at the ratio 2:1. In that combination the level of GSH was 24.9±2.4 nmol g⁻³ of proteins (vs. 70.2±3.2 nmol g⁻³ in the control) and the level of MDA was 72.3±3.1 nmol g⁻³ (vs. 23.6±9.1 nmol g⁻³ in the control). It is generally assumed that 10-HDA, an important constituent of RJ, together with HuIFN-αN3, is responsible for the inhibition of CaCo-2 cells proliferation in vitro. In our study, however, RJ and HuIFN-αN3 applied at 2:1 decreased the level of GSH the most and significantly increased lipid peroxidation via MDA in CaCo-2 cells. Future studies should show whether these GSH- and MDA-related activities of RJ, HuIFN-αN3, 10-HDA, and their combinations may decrease the tumorigenicity index and tumorigenic potential of various tumour cells in vitro.
351. Promoting tumor penetration of nanoparticles for cancer stem cell therapy by TGF-β signaling pathway inhibition.
作者: Zu-Qi Zuo.;Kai-Ge Chen.;Xiao-Yuan Yu.;Gui Zhao.;Song Shen.;Zhi-Ting Cao.;Ying-Li Luo.;Yu-Cai Wang.;Jun Wang.
来源: Biomaterials. 2016年82卷48-59页
Cancer stem cells (CSCs), which hold a high capacity for self-renewal, play a central role in the development, metastasis, and recurrence of various malignancies. CSCs must be eradicated to cure instances of cancer; however, because they can reside far from tumor vessels, they are not easily targeted by drug agents carried by nanoparticle-based drug delivery systems. We herein demonstrate that promoting tumor penetration of nanoparticles by transforming growth factor β (TGF-β) signaling pathway inhibition facilitates CSC therapy. In our study, we observed that although nanoparticles carrying siRNA targeting the oncogene polo-like kinase 1 (Plk1) efficiently killed breast CSCs derived from MDA-MB-231 cells in vitro, this intervention enriched CSCs in the residual tumor tissue following systemic treatment. However, inhibition of the TGF-β signaling pathway with LY364947, an inhibitor of TGF-β type I receptor, promoted the penetration of nanoparticles in tumor tissue, significantly ameliorating the intratumoral distribution of nanoparticles in MDA-MB-231 xenografts and further leading to enhanced internalization of nanoparticles by CSCs. As a result, synergistic treatment with a nanoparticle drug delivery system and LY364947 inhibited tumor growth and reduced the proportion of CSCs in vivo. This study suggests that enhanced tumor penetration of drug-carrying nanoparticles can enhance CSCs clearance in vivo and consequently provide superior anti-tumor effects.
352. Synthesis and structure of new dicopper(II) complexes bridged by N-(2-hydroxy-5-methylphenyl)-N'-[3-(dimethylamino)propyl]oxamide with in vitro anticancer activity: A comparative study of reactivities towards DNA/protein by molecular docking and experimental assays.
作者: Kang Zheng.;Mei-Xing Yan.;Yan-Tuan Li.;Zhi-Yong Wu.;Cui-Wei Yan.
来源: Eur J Med Chem. 2016年109卷47-58页
Two new dicopper(II) complexes bridged by N-(2-hydroxy-5-methylphenyl)-N'-[3-(dimethyl-amino)propyl]oxamide (H3hmpoxd), and end-capped with 4,4'-dimethyl-2,2'-bipyridine (Me2bpy) and 2,2'-bipyridine (bpy), were synthesized and structurally characterized, namely [Cu2(hmpoxd)(CH3OH)(Me2bpy)](ClO4) (1) and [Cu2(hmpoxd)(bpy)](ClO4)∙CH3OH (2). The single-crystal X-ray diffraction analysis reveals that the endo- and exo-copper (II) ions bridged by the cis-hmpoxd(3-) ligand are located in square-planar and square-pyramidal geometries, respectively, for 1, and square-planar environments in 2. The DNA/protein-binding natures are studied theoretically and experimentally, indicating that both the two complexes can interact with the DNA in the mode of intercalation, and effectively quench the intrinsic fluorescence of protein BSA via the favored binding sites Trp213 for 1 and Trp134 for 2. In vitro anticancer activities showed that the two complexes are active against the selected tumor cell lines, and the anticancer activities are consistent with their DNA/BSA-binding affinities following the order of 1 > 2. The synergistic hydrophobicity of the bridging and terminal ligands in these complexes on DNA/BSA-binding events and in vitro anticancer activities is preliminarily discussed.
353. Design and synthesis of novel selective anaplastic lymphoma kinase inhibitors.
作者: Pierre-Yves Michellys.;Bei Chen.;Tao Jiang.;Yunho Jin.;Wenshuo Lu.;Thomas H Marsilje.;Wei Pei.;Tetsuo Uno.;Xuefeng Zhu.;Baogen Wu.;Truc Ngoc Nguyen.;Badry Bursulaya.;Christian Lee.;Nanxin Li.;Sungjoon Kim.;Tove Tuntland.;Bo Liu.;Frank Sun.;Auzon Steffy.;Tami Hood.
来源: Bioorg Med Chem Lett. 2016年26卷3期1090-1096页
Anaplastic lymphoma kinase (ALK) is a receptor tyrosine kinase belonging to the insulin receptor superfamily. Expression of ALK in normal human tissues is only found in a subset of neural cells, however it is involved in the genesis of several cancers through genetic aberrations involving translocation of the kinase domain with multiple fusion partners (e.g., NPM-ALK in anaplastic large cell lymphoma ALCL or EML4-ALK in non-small cell lung cancer) or activating mutations in the full-length receptor resulting in ligand-independent constitutive activation (e.g., neuroblastoma). Here we are reporting the discovery of novel and selective anaplastic lymphoma kinase inhibitors from specific modifications of the 2,4-diaminopyridine core present in TAE684 and LDK378. Synthesis, structure activity relationships (SAR), absorption, distribution, metabolism, and excretion (ADME) profile, and in vivo efficacy in a mouse xenograft model of anaplastic large cell lymphoma are described.
354. Targeting cancer cells with oleanolic and ursolic acid derived hydroxamates.
Oleanolic and ursolic acid derived hydroxamates were easily obtained from their parent compounds; they were screened for their cytotoxicity applying SRB assays employing several human tumor cell lines. Low EC50 values were determined for compounds in which the nitrogen as well as the oxygen in the hydroxamic acid part still holds acidic hydrogens. Thus, ursolic acid derived compounds having at least an OH and/or NH moiety in the hydroxamate part of the molecule showed good cytotoxicity but they are significantly less selective for the tumor cells than oleanolic acid derived compounds. Good results were determined for oleanolic acid derived 7 for tumor cell lines 518A2 (melanoma, EC50=3.3 μM), A2780 (ovarian carcinoma, EC50=3.4 μM) and HT29 (colon adenocarcinoma, EC50=5.6 μM) while being significantly less cytotoxic for fibroblasts (EC50=20.4 μM).
355. Composition, in vitro Cytotoxicity, and Anti-mildew Activities of the Leaf Essential Oil of Machilus thunbergii from Taiwan.
This study investigated the chemical composition, in-vitro cytotoxicity, and anti-mildew fungal activities of the essential oil isolated from the leaf of Machilus thunbergii from Taiwan. The essential oil was isolated using hydrodistillation in a Clevenger-type apparatus, and characterized by GC-FID and GC-MS. Eighty-three compounds were identified, representing 99.8% of the oil. The main components identified were n-decanal (26.6%), β-caryophyllene (15.8%), α-humulene (10.8%), and β-eudesmol (10.5%). The oil exhibited cytotoxic activity against human oral, liver, lung, colon, melanoma, and leukemic cancer cells. The active source compounds were β-caryophyllene, a-humulene, and β-eudesmol. The anti-mildew activity of the leaf oil was also evaluated. Results showed that the leaf oil had excellent anti-mildew activity. For the anti-mildew activity of the leaf oil, the active source compound was determined to be β-eudesmol.
356. Bioassay-guided Isolation of Antiproliferative Triterpenoids from Euonymus alatus Twigs.
作者: Hee Rae Kang.;Hee Jeong Eom.;Seoung Rak Lee.;Sang Un Choi.;Ki Sung Kang.;Kang Ro Lee.;Ki Hyun Kim.
来源: Nat Prod Commun. 2015年10卷11期1929-32页
Euonymus alatus (Celastraceae) has been used as an anticancer agent in Korean traditional medicine. However, the potential bioactive contributors to the anticancer effects have not been thoroughly studied. Our screening test revealed that the MeOH extract of E. alatus twigs exhibited significant cytotoxicity against A549, SK-OV-3, and SK-MEL-2 cell lines. A bioassay-guided separation of the MeOH extract of E. alatus twigs resulted in the isolation and identification of 14 triterpenes as main phytochemicals. The structures of the compounds were elucidated on the basis of spectroscopic evidence as lupeol (1), betulin (2), 3β,28,30-lup-20(29)-ene triol (3), lupenone (4), betulone (5), 28,30-dihydroxy-3-oxolup-20(29)-ene (6), messagenin (7), glut-5-en-3β-ol (8), maslinic acid (9), hederagenin (10), 3-oxo-11α-methoxyolean-12-ene (11), 3β-hydroxy-1-oxo-olean-12-en-28-oic acid (12), ursolic acid (13), and 2a-hydroxy- ursolic acid (14). Of these compounds, 3, 6-8, and 10-14 were isolated for the first time from this plant. All isolated triterpenoids had consistent antiproliferative activities against A549, SK-OV-3, SK-MEL-2, and HCT-15 cell lines. Compounds 2, 5, and 7 showed significant cytotoxicity against all four cell lines tested, with IC50 values of 3.26-8.61 µM.
357. Periodontal Disease, Dental Implants, Extractions and Medications Related to Osteonecrosis of the Jaws.
作者: Neha P Shah.;Helen Katsarelis.;Michael Pazianas.;Daljit K Dhariwal.
来源: Dent Update. 2015年42卷9期878-80, 883-4, 887-89页
Patients taking bisphosphonates and other anti-resorptive drugs are likely to attend general dental practice. The term 'bisphosphonate'is often immediately associated with osteonecrosis of the jaws (ONJ). Risk assessment and subsequent management of these patients should be carried out taking into account all the risk factors associated with ONJ. The introduction of newer drugs, also shown to be associated with ONJ, demands increased awareness of general dental practitioners about these medications. CPD/CLINICAL RELEVANCE: This paper provides an update on medication-related ONJ and considers the effects of anti-resorptive drugs on the management of patients needing exodontia, treatment for periodontal disease and dental implant placement.
358. [Charles Bonnet syndrome secondary to intravitreal ranibizumab in a patient with exudative age-related macular degeneration].
作者: Pilar Cifuentes-Canorea.;Nestor Ventura-Abreu.;Julián García-Feijoo.;Enrique Santos-Bueso.
来源: Med Clin (Barc). 2016年146卷11期516-7页 359. Silibinin derivatives as anti-prostate cancer agents: Synthesis and cell-based evaluations.
作者: Bao Vue.;Sheng Zhang.;Xiaojie Zhang.;Konstantinos Parisis.;Qiang Zhang.;Shilong Zheng.;Guangdi Wang.;Qiao-Hong Chen.
来源: Eur J Med Chem. 2016年109卷36-46页
This study aims to systematically explore the alkylation effect of 7-OH in silibinin and 2,3-dehydrosilibinin on the antiproliferative potency toward three prostate cancer cell lines. Eight 7-O-alkylsilibinins, eight 7-O-alkyl-2,3-dehydrosilibinins, and eight 3,7-O-dialkyl-2,3-dehydrosilibinins have been synthesized from commercially available silibinin for the in vitro cell-based evaluation. The WST-1 cell proliferation assay indicates that nineteen out of twenty-four silibinin derivatives have significantly improved antiproliferative potency when compared with silibinin. 7-O-Methylsilibinin (2) and 7-O-ethylsilibinin (3) have been identified as the most potent compounds with 98- and 123-fold enhanced potency against LNCaP human androgen-dependent prostate cancer cell line. Among 2,3-dehydrosilibinin derivatives, 7-O-methyl-2,3-dehydrosilibinin (10) and 7-O-ethyl-2,3-dehydrosilibinin (11) have been identified as the optimal compounds with the highest potency towards both androgen-dependent LNCaP and androgen-independent PC-3 prostate cancer cell lines. 7-O-Ethyl-2,3-dehydrosilibinin (11) was demonstrated to arrest PC-3 cell cycle at the G0/G1 phase and to induce PC-3 cell apoptosis. The findings in this study suggest that antiproliferative potency of silibinin and 2,3-dehydrosilibinin can be appreciably enhanced through suitable chemical modifications on the phenolic hydroxyl group at C-7 and that introduction of a chemical moiety with the potential to improve bioavailability through a linker to 7-OH in silibinin and 2,3-dehydrosilibinin would be a feasible strategy for the development of silibinin derivatives as anti-prostate cancer agents.
360. Targeting BRCA1 and BRCA2 Deficiencies with G-Quadruplex-Interacting Compounds.
作者: Jutta Zimmer.;Eliana M C Tacconi.;Cecilia Folio.;Sophie Badie.;Manuela Porru.;Kerstin Klare.;Manuela Tumiati.;Enni Markkanen.;Swagata Halder.;Anderson Ryan.;Stephen P Jackson.;Kristijan Ramadan.;Sergey G Kuznetsov.;Annamaria Biroccio.;Julian E Sale.;Madalena Tarsounas.
来源: Mol Cell. 2016年61卷3期449-460页
G-quadruplex (G4)-forming genomic sequences, including telomeres, represent natural replication fork barriers. Stalled replication forks can be stabilized and restarted by homologous recombination (HR), which also repairs DNA double-strand breaks (DSBs) arising at collapsed forks. We have previously shown that HR facilitates telomere replication. Here, we demonstrate that the replication efficiency of guanine-rich (G-rich) telomeric repeats is decreased significantly in cells lacking HR. Treatment with the G4-stabilizing compound pyridostatin (PDS) increases telomere fragility in BRCA2-deficient cells, suggesting that G4 formation drives telomere instability. Remarkably, PDS reduces proliferation of HR-defective cells by inducing DSB accumulation, checkpoint activation, and deregulated G2/M progression and by enhancing the replication defect intrinsic to HR deficiency. PDS toxicity extends to HR-defective cells that have acquired olaparib resistance through loss of 53BP1 or REV7. Altogether, these results highlight the therapeutic potential of G4-stabilizing drugs to selectively eliminate HR-compromised cells and tumors, including those resistant to PARP inhibition.
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