Codominance of cisplatin resistance in somatic cell hybrids

Intrinsic or acquired resistance to cisplatin in cancer cells remains a major obstacle to successful chemotherapy. The clinically relevant genetic and molecular mechanisms of resistance have not yet been identified. Cisplatin-resistant (CP-r) human KB epidermoid carcinoma cell lines (HeLa) resistant to varying levels of cisplatin after single and multiple selection steps are cross-resistant to other platinum compounds and to methotrexate. Intraspecies hybrids of the sensitive and KB CP-r cells were fused with HeLa D98(OR) CP-s, hypoxanthine-aminopterin-thymidine (HAT) sensitive, ouabain resistant, to determine whether cisplatin resistance is dominant or recessive. Cell-cell hybridization between the sensitive cells and single-step or two-step KB CP-r cells both indicated codominance of cisplatin resistance compared to hybrids between sensitive cell lines (D98(OR)xKB). The hybrids between sensitive cell lines (D98xKB) and a single-step CP-r KB cell line (D98xKB-CP.5) also were cross-resistant to carboplatin and methotrexate. In addition, the relatively slower growth rate of CP-r cells appears to be dominant. In the two-step CP-r KB cell line, KB-CP1, resistance is no more dominant than in the single-step CP-r KB cell line, KB-CP.5, suggesting that one of the two steps of resistance in KB-CP1 may not be dominant. These dominance data suggest that it might be possible to identify one or more genes responsible for cisplatin resistance by gene transfer from a resistant cell line to a sensitive cell line.     

A pleiotropic defect reducing drug accumulation in cisplatin-resistant cells

The resistance of tumors to cisplatin remains a major cause of treatment failure in cancer patients. Multiple, simultaneous alterations are frequently encountered in cancer cells selected for cisplatin resistance. To determine whether the complex phenotype results from many different cellular alterations, single-step variants were isolated based on one-step selection in cisplatin. Reduced drug accumulation is a common feature of cisplatin-resistant (CP-r) cancer cells, which is probably caused by one or more dominant genes. Pulse-chase labeling and pulse-chase biotinylation of cell surface proteins suggest that membrane protein mislocalization occurs in CP-r cells, caused mainly by a defect in plasma membrane protein recycling, manifested also as a defect in acidification of lysosomes. This membrane protein mislocalization is presumed to reduce cell surface expression of a putative cisplatin carrier or carriers. In cells selected in several steps, decreased expression of folate-binding protein and arsenic-binding proteins, and reduced endocytosis were detected in CP-r cells, contributing to the reduced uptake of cisplatin, methotrexate and other related compounds. Multiple mechanisms in CP-r cells keep cytotoxic platinum compounds out of cells through defective expression of cell surface proteins such as transporters and carriers, and decreased expression of proteins involved in endocytosis.     

植物多倍体中的基因组印记

植物多倍体在自然界中广泛存在,这说明拥有多套遗传物质使得多倍体的适应进化具有优势。新多倍体形成后,一些基因组范围的变化较迅速地发生在多倍体形成开端,另一些在长期进化中发生。由于受到遗传、表观等因素的影响,亲本对于新形成多倍体基因组的贡献不均衡。这种偏向于某个亲本基因组的显性优势,称为基因组印记。植物多倍体中的基因组印记表现为基因组偏向性的序列消除、不均衡基因表达、基因沉默,这些受到基因组合并及DNA甲基化、核仁显性等表观因素影响。本文旨在为多倍体基因组进化及育种的相关研究提供参考。     

综述——纳米材料与药物输递：基于肿瘤异常结构的纳米药物设计

肿瘤组织的血液供给在时间和空间上存在的非均质性、血管的高渗性、淋巴排出功能的低效性共同形成肿瘤微环境,阻碍治疗药物有效地运输到肿瘤,从而影响其疗效．与传统药物相比,纳米药物能优先递送到肿瘤,并具有多药载药与靶向运输等功能．但肿瘤中特有生理屏障的存在阻碍了纳米药物以有效浓度均匀地运输到肿瘤组织．一些美国食品药品管理局批准的纳米药物疗效并不显著,可能与这些生理屏障的阻碍有关．本文概述了肿瘤治疗时药物需跨过的生理屏障,并总结了克服这些生理屏障的方法,探讨了纳米药物研发时针对肿瘤异常结构优化药物递送需考虑的因素．     

7,8-secolignans from Schisandra wilsoniana and their anti-HIV-1 activities

Two new 7,8‐secolignans, marphenols A and B ( 1 and 2 , resp.), together with a known related derivative, 7,8‐secoholostylone B ( 3 ), were isolated from the stems of Schisandra wilsoniana. The structures of 1 and 2 were elucidated by spectroscopic methods, including extensive 1D‐ and 2D‐NMR techniques. The anti‐HIV‐1 activities of 1 – 3 were evaluated. Compound 1 inhibited HIV‐1_IIIB‐induced syncytia formation with an EC₅₀ value of 0.55 μg ml^?1. It reduced p24 antigen expression in acutely HIV‐1_IIIB‐infected C8166 cells and primary isolate HIV‐1_TC‐2‐infected peripheral blood mononuclear cells (PBMCs), with EC₅₀ values of 3.34 and 0.52 μg ml^?1, respectively. It showed no effects on the HIV‐1_IIIB replication in chronically infected H9 cells as well as fusion inhibition.     

Trafficking and localization of platinum complexes in cisplatin-resistant cell lines monitored by fluorescence-labeled platinum

Cisplatin is a chemotherapeutic agent commonly used in the treatment of a wide variety of malignant tumors. Resistance to cisplatin represents a major obstacle to effective cancer therapy because clinically significant levels of resistance quickly emerge after treatment. Based on previous studies indicating abnormal plasma membrane protein trafficking in cisplatin-resistant (CP-r) cells, Fluorescence (Alexa Fluor)-labeled cisplatin was used to determine whether this defect altered the trafficking and localization of cisplatin by comparing drug sensitive KB-3-1 and KB-CP-r cells. Alexa Fluor-cisplatin was readily internalized and localized throughout the KB-3-1 cells, but overall fluorescence decreased in KB-CP-r cells, as detected by flow cytometry (FACS) and confocal microscopy. Only punctate cytoplasmic staining was observed in KB-CP-r cells with less fluorescence observed in the nucleus. Colocalization experiments with a Golgi-selective stain indicate the involvement of Golgi-like vesicles in initial intracellular processing of Alexa Fluor conjugated cisplatin complexes. As detected using an antibody to Alexa Fluor-cisplatin, cisplatin complex-binding proteins (CCBPs) were reduced in membrane fractions of single-step cisplatin-resistant KB-CP.5 cells, and increased in the cytoplasm of KB-CP.5 cells compared to KB-3-1 cells. CCBPs localized to lower density fractions in KB-CP.5 cells than in KB-3-1 cells as determined by iodixanol gradient centrifugation. In summary, inappropriate trafficking of CCBPs might explain resistance to cisplatin in cultured cancer cells, presumably because membrane binding proteins for cisplatin are not properly located on the cell surface in these cells, but are instead trapped in low density vesicles within the cytoplasm.     

膜荚黄芪活性成分研究

对膜荚黄芪（Astragatus membranaceus (Fisch.)Bunge）的成分进行了系统分离和鉴定,同时用E- 112顺磁共振仪测定了以芒柄花素为代表的异黄酮类化合物清除超氧自由基的活性,结果证明黄芪中的异黄酮类化合物具有清除超氧阴离子的活性。这可能是黄芪药物具有治疗心力衰竭和抗衰老的活性机理之一,在分离过程中,得到15种结晶,经化学降解和光谱分析分别鉴定为:晶Ⅰ:蔗糖（sucrose）,晶Ⅱ:黄芪皂甙Ⅳ（astragaloside Ⅳ）,晶Ⅲ:芒柄花素（formononetin）,晶Ⅳ:毛蕊异黄酮（calycosin）,晶V:黄芪皂甙Ⅵ（astragaloside Ⅵ）,晶Ⅵ:（3R）7,2’-二羟基-5’,6’二甲氧基异黄烷-7-O-β-D葡萄糖甙,晶Ⅶ:黄芪皂甙Ⅱ（astragaloside Ⅱ）,晶Ⅶ:黄芪皂甙Ⅱ（astragaloside Ⅱ）,晶Ⅷ:黄芪皂甙Ⅲ(astragaloside Ⅲ）,晶Ⅸ:β-谷甾醇（β-sitosterol),晶Ⅹ:棕榈酸（palmitic acid）,晶Ⅺ:胡萝卜甙（daucosterol),晶XⅡ～XV结构待定,本文主要报道晶Ⅲ的活性及晶Ⅵ的结构鉴定,晶Ⅵ为一新化合物。     

Highly Oxygenated Labdane Diterpenoids from Stevia rebaudiana and Their Anti-Atherosclerosis Activities

Five unknown labdane diterpenoids Stevelins A–E ( 1–5 ), three known labdane diterpenoids ( 6–8 ) and three labdane norditerpenoids ( 9–11 ) were isolated from the Stevia rebaudiana. The structures were determined primarily via NMR spectroscopic data and HR-ESI-MS experiments. X-ray crystallography using CuK_α radiation was used to determine the absolute configurations of 1 , and the absolute configurations of 2–5 were deduced by electronic circular dichroism (ECD) calculations. The potential anti-atherosclerosis activities of all compounds were evaluated by measuring their inhibitory effects on the macrophage foam cell formation. As a result, most isolated compounds could significantly inhibit oxidized low-density lipoprotein (ox-LDL)-induced macrophage foam cell formation, which suggests that these compounds may be promising candidates in the treatment for atherosclerosis.     

Smart calcium peroxide with self-sufficience for biomedicine

正Oxygen (O_2) supplementation plays a key role in the treatment of some hypoxia-associated diseases, such as solid tumors, tissue damage, and type-1 diabetes (T1D). Various strategies have been developed to address the hypoxia aspect     

RNAi therapeutic and its innovative biotechnological evolution

Recently, United States Food and Drug Administration (FDA) and European Commission (EC) approved Alnylam Pharmaceuticals' RNA interference (RNAi) therapeutic, ONPATTRO? (Patisiran), for the treatment of the polyneuropathy of hereditary transthyretin-mediated (hATTR) amyloidosis in adults. This is the first RNAi therapeutic all over the world, as well as the first FDA-approved treatment for this indication. As a milestone event in RNAi pharmaceutical industry, it means, for the first time, people have broken through all development processes for RNAi drugs from research to clinic. With this achievement, RNAi approval may soar in the coming years. In this paper, we introduce the basic information of ONPATTRO and the properties of RNAi and nucleic acid therapeutics, update the clinical and preclinical development activities, review its complicated development history, summarize the key technologies of RNAi at early stage, and discuss the latest advances in delivery and modification technologies. It provides a comprehensive view and biotechnological insights of RNAi therapy for the broader audiences.