Arsenic inhibits induction of cytochrome P450 1A1 by 2,3,7,8-tetrachlorodibenzo-p-dioxin in human hepatoma cells

The aim of this study was to examine the arsenic effect on activation of aryl hydrocarbon receptor (AhR)-mediated gene expression by 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) in human hepatoma cells. The human hepatoma Huh7 cells were treated with sodium arsenite (NaAsO2) from 0.5 to 20 microM for 24 h. Our data revealed that NaAsO2 < or = 10 microM caused no significant cytotoxic effect on Huh7 cells (p>0.05). We also established a dioxin-responsive element (DRE)-mediated Chemical Activated LUciferase eXpression (CALUX) cell line, Huh7-DRE-Luc, by stable transfection of Huh7 with a DRE-driven firefly luciferase reporter plasmid (4xDRE-TATA-Luc). Treatments of Huh7-DRE-Luc and Huh7 with NaAsO2 attenuated the 2,3,7,8-TCDD-induced DRE-CALUX and cytochrome P450 1A1 (CYP1A1) activations, respectively, in a dose-dependent manner. We found that the calculated CALUX-toxic equivalent (TEQ) levels induced by cotreatment of NaAsO2 > or = 3.0 microM and 10 nM 2,3,7,8-TCDD were significantly lower than that induced by 2,3,7,8-TCDD alone (p<0.05). In the present study, we demonstrated that arsenic not only inhibited the TCDD-induced CYP1A1 activation but also interfered with DRE-CALUX bioassay in human hepatoma cells. Our finding also suggests that extensive cleanup of sample for removal of any possible interfering factor is critical to guarantee the accuracy of dioxin-TEQ levels using DRE-CALUX bioassay.     

外源化合物肝毒性体外模型的研究现状和进展

肝脏是人体最为重要的器官之一,在人体中承担着重要的消化和解毒功能。目前全球关于肝毒性的研究大多以动物为实验对象,然而随着“3R”原则——替代(Replacement)、减少(Reduction)、优化(Refinement)在研究中得到更多的实行,更多的体外毒理学模型被建立且运用到肝毒性的研究当中。此篇综述主要提供了对于一些体外肝毒性毒理学模型的简要、关键的评估,以及对未来发展方向的展望。     

富锌姬松茸胞内多糖的分离及体内抑制小鼠肝癌的研究

研究了经DEAE-纤维素离子交换柱分离的富锌液态发酵姬松茸胞内多糖组分对小鼠肝癌实体型Heps的体内抑制效果,同时考察了柱层析过后各组分中锌元素的分布情况及给药后小鼠血清锌的变化情况。分离所得组分MP-2在5 mg/(kg.d)剂量下抑瘤率为59.5%(p<0.001),MP-3在10 mg/(kg.d)剂量下抑瘤率为68.1%(p<0.001),两样品在10 mg/(kg.d)剂量下均能使小鼠脾指数显著提高。组分MP-2含锌率3.38‰、MP-3含锌率2.46‰,远高于组分MP-1的含锌率0.12‰;注射样品MP-2、MP-3的实验组小鼠血清锌浓度皆显著高于不给予富锌样品的阴性对照组(p<0.05)。     

磺化竹红菌乙素对小鼠肝癌细胞光敏作用研究

本文首次研究了小鼠腹水肝癌细胞对于磺化竹红菌乙素摄取的过程，并对细胞的光敏损伤进行了初步研究，结果表明：磺化乙素在水中有较大溶解度，细胞摄取与外界溶液浓度呈相关性与乙素比较对于细胞的杀伤能力相当，也能导致细胞膜脂过氧化。     

16O6+辐照诱导的人肝癌细胞DNA双链断裂及其修复

用倒转脉冲场凝胶电泳（ＰＩＧＥ）研究了３．１７ＭｅＶ／ｕ＾１６Ｏ＾６＋诱导的肝癌细胞ＤＮＡ双链断裂（ＤＳＢ）及其修复效应。结果表明：ＤＳＢ的诱导与辐照剂 量呈正相关,其产额为０．４３ＤＳＢｓ／１００Ｍｂｐ：Ｇｙ,与＾６０Ｃｏγ射线相比相对生物学效应为１．６９。ＤＳＢ片段重接一半所需要的时间（ｔ１／２）剂量有关,剂量越大,ｔ１／２越长。重接的方式主要表现为小片从而连接为较大的片段。     

康赛宁对体外培养的人肝癌细胞的影响及与乙肝疫苗联合免疫对小鼠的免疫增强作用

目的研究A群溶血性链球菌制剂(康赛宁)对体外培养的人肝癌细胞系Hep3B和HepG22.2.15的影响及与乙肝疫苗联合免疫对小鼠的免疫增强作用。方法用不同浓度的康赛宁作用于人肝癌细胞Hep3B和HepG22.2.15,观察细胞形态学,MTT比色法检测细胞活性,EIA法检测培养上清HBsAg、HBeAg含量,吖啶橙直接染色检测细胞凋亡,Southernblot分析细胞DNA片段。给NIH小鼠腹腔注射康赛宁和乙肝疫苗,检测血清中HBs抗体、转氨酶水平。给普通小鼠腹腔注射康赛宁和乙肝疫苗,观察注射前后的体重变化。结果康赛宁可抑制HBsAg及HBeAg的分泌,使染色体DNA发生有规律的断裂,促使细胞发生凋亡。与乙肝疫苗联合免疫,可提高小鼠血清中HBs抗体水平。无论单用或合用康赛宁,对小鼠均无明显毒副作用。结论康赛宁对体外培养的人肝癌细胞系有影响,与乙肝疫苗联合免疫对小鼠有免疫增强作用。     

HAP纳米粒子与传统抗癌药物的抗癌效果比较

采用MTT法检测HAP纳米粒子及5种传统化疗药物对体外培养肝癌Bel-7402细胞及正常对照细胞的敏感性，研究对比HAP纳米粒子及传统抗癌药物对体外肝癌细胞的作用特点。在相同的作用时间内，不同浓度的常用抗癌药物大部分表现出良好的抑癌效果，而HAP纳米粒子较大部分化疗药物对肝癌细胞抑制作用低，但对于正常对照细胞无影响，结果HAP纳米粒子能够作为一种抗癌药物，与传统抗癌药物相比，它存在着优越性。     

Synthesis of 9,9‐Dialkyl‐4,5‐diazafluorene Derivatives and Their Structure–Activity Relationships Toward Human Carcinoma Cell Lines

A homologous set of 9,9‐dialkyl‐4,5‐diazafluorene compounds were prepared by alkylation of 4,5‐diazafluorene with the appropriate alkyl bromide and under basic conditions. The structures of these simple organic compounds were confirmed by spectroscopic techniques (FTIR, NMR, and FABMS). Their biological effects toward a panel of human carcinoma cells, including Hep3B hepatocellular carcinoma, MDAMB‐231 breast carcinoma, and SKHep‐1 hepatoma cells, were investigated; a structure–activity correlation was established with respect to the length of the alkyl chain and the fluorene ring structure. The relationship between the mean potency [log(1/IC₅₀)] and alkyl chain length was systematically studied. The results show that compounds with butyl, hexyl, and octyl chains exhibit good growth inhibitory effects toward these three human carcinoma cell lines, and the 9,9‐dihexyl‐4,5‐diazafluorene further exhibits antitumor activity in athymic nude mice Hep3B xenograft models. For the structurally related dialkylfluorenes that lack the diaza functionality, in vitro cytotoxicity was not observed at clinically relevant concentrations.     

New 3-Aryl-2-(2-thienyl)acrylonitriles with High Activity Against Hepatoma Cells

New 2-(thien-2-yl)-acrylonitriles with putative kinase inhibitory activity were prepared and tested for their antineoplastic efficacy in hepatoma models. Four out of the 14 derivatives were shown to inhibit hepatoma cell proliferation at (sub-)micromolar concentrations with IC₅₀ values below that of the clinically relevant multikinase inhibitor sorafenib, which served as a reference. Colony formation assays as well as primary in vivo examinations of hepatoma tumors grown on the chorioallantoic membrane of fertilized chicken eggs (CAM assay) confirmed the excellent antineoplastic efficacy of the new derivatives. Their mode of action included an induction of apoptotic capsase-3 activity, while no contribution of unspecific cytotoxic effects was observed in LDH-release measurements. Kinase profiling of cancer relevant protein kinases identified the two 3-aryl-2-(thien-2-yl)acrylonitrile derivatives 1b and 1c as (multi-)kinase inhibitors with a preferential activity against the VEGFR-2 tyrosine kinase. Additional bioinformatic analysis of the VEGFR-2 binding modes by docking and molecular dynamics calculations supported the experimental findings and indicated that the hydroxy group of 1c might be crucial for its distinct inhibitory potency against VEGFR-2. Forthcoming studies will further unveil the underlying mode of action of the promising new derivatives as well as their suitability as an urgently needed novel approach in HCC treatment.     

Self-Assembled Polymeric Micelles Based on Hyaluronic Acid-g-Poly(d,l-lactide-co-glycolide) Copolymer for Tumor Targeting

Graft copolymer composed hyaluronic acid (HA) and poly(d,l-lactide-co-glycolide) (PLGA) (HAgLG) was synthesized for antitumor targeting via CD44 receptor of tumor cells. The carboxylic end of PLGA was conjugated with hexamethylenediamine (HMDA) to have amine end group in the end of chain (PLGA-amine). PLGA-amine was coupled with carboxylic acid of HA. Self-assembled polymeric micelles of HAgLG have spherical morphologies and their sizes were around 50–200 nm. Doxorubicin (DOX)-incorporated polymeric micelles were prepared by dialysis procedure. DOX was released over 4 days and its release rate was accelerated by the tumoric enzyme hyaluronidase. To assess targetability of polymeric micelles, CD44-positive HepG2 cells were employed treated with fluorescein isothiocyanate (FITC)-labeled polymeric micelles. HepG2 cells strongly expressed green fluorescence at the cell membrane and cytosol. However, internalization of polymeric micelles were significantly decreased when free HA was pretreated to block the CD44 receptor. Furthermore, the CD44-specific anticancer activity of HAgLG polymeric micelles was confirmed using CD44-negative CT26 cells and CD44-positive HepG2 cells. These results indicated that polymeric micelles of HaLG polymeric micelles have targetability against CD44 receptor of tumor cells. We suggest HAgLG polymeric micelles as a promising candidate for specific drug targeting.