肝素单独应用及与红比霉素、阿霉素联合应用抑制结膜成纤维细胞增殖

我们测定了肝素单独应用及肝素分别与红比霉素、阿霉素联合应用在体外对兔结膜成纤维细胞的影响。证实肝素单独应用可明显抑制结膜成纤维细胞增殖,肝素的ID_(50)值为1.93mg/ml,肝素单独应用抑制成纤维细胞生长的效力比其与红比霉素或阿霉素联合应用的效力更大。肝素无明显副作用,有希望成为提高青光眼手术成功率的理想药物。     

Efficacy and safety of pegylated liposomal doxorubicin in primary cutaneous B‐cell lymphomas and comparison with the commonly used therapies

Objectives: The therapy of advanced, relapsed or refractory primary cutaneous lymphomas is often unsatisfactory. Recent data indicate a favourable pharmacokynetic, pharmacodynamic and toxicity profile of pegylated liposomal doxorubicin (Peg‐Doxo) in primary cutaneous T‐cell lymphomas, while in primary cutaneous B‐cell lymphomas (PCBCLs), the drug efficacy has never been assessed so far. Methods: We performed a prospective phase II pilot clinical trial of Peg‐Doxo monotherapy (20 mg/m²) in PCBCLs. One patient had a marginal zone B‐cell lymphoma and four were affected by diffuse large B‐cell lymphoma‐leg type, all with widespread nodular lesions. Results: All the patients achieved a complete response (CR = 100%) in a short period of time (median 3 months), even when pretreated with radio‐chemotherapy. Two experienced a relapse. At follow‐up, one patient died for progressive disease; four are in CR after 5, 52, 63 and 69 months. As concerning the toxicity profile, the treatment was well‐tolerated, no one decreased or delayed the dose. The haematological toxicity was mild with only one case of grade III neutropenia; a patient showed a grade I neurotoxicity. Dermatological toxicity, in particular the palmar–plantar erythrodysesthesia, did not occurred, probably because of both the low dosages of Peg‐Doxo monotherapy and the oral prophylaxis with pyridoxine. Conclusions: In spite of the small number of patients, it emerges that monochemotherapy with Peg‐Doxo has a significantly high clinical activity and a good safety profile in PCBCLs, even in aggressive forms, compared with other therapeutic regimens, which are completely reviewed. It suggests the need of further investigations in this field.     

Cellular effects of genotoxic stress and gene silencing of the checkpoint kinases in human oral cells

Backround:  The human oral cells have different physiological properties and different origins in developmental stages. Mechanical, physiological, and chemical stress can cause damage and irritation during clinical treatment in various oral tissues.
Purpose:  The effects of DNA damage response and gene silencing of checkpoint kinases (Chk1/2) is not unclear in oral primary and cancer cells.
Method:  Treatment with doxorubicin involving DNA damage and gene silencing of Chk1/2 by shRNA constructs was performed in pulp, periodontal ligament, gingival tissues (HGF), and mouth epithelial carcinoma cells (KB).
Results:  The KB cells were more sensitive to genotoxic stress response than oral primary cells. Endogenous levels of Chk1/2 in KB cell were higher than in pulp cells. When doxorubicin was administered, Chk2 activation was induced in KB cell, but not in pulp cells. However, viability in KB cells did not decrease by the suppression of the checkpoint proteins, whereas primary cells were defective in gene silencing. When doxorubicin treatment and gene silencing were combined, both primary cells and KB cell were defective. Moreover, in case of KB cell, cell death was increased and activation of Chk2 was increased in doxorubicin dose-dependent.
Conclusion:  These data indicate that not only stress response mechanism may be different in oral primary and cancer cells but also Chk1/2 proteins may have essential roles in oral primary cells. Based on these data, checkpoint proteins may be crucial drug targets for oral cancer therapy.     

奥曲肽修饰的N-辛基-O,N-羧甲基壳聚糖的合成、表征及其作为阿霉素递送载体的研究

以奥曲肽（OCT）为靶基团修饰两亲性壳聚糖衍生物N-辛基-O,N-羧甲基壳聚糖(OCC）,并考察其作为抗肿瘤药物阿霉素（DOX）增溶载体的可行性。以聚乙二醇（PEG）为化学连接臂,通过活化酯反应将OCT偶联于OCC上,并通过¹H NMR对其进行结构表征;采用透析法制备包载阿霉素（DOX）的主动靶向胶束（DOX-OCT-PEG-OCC）,并考察其理化性质;采用透析法研究DOX-OCT-PEG-OCC胶束在不同介质中的释放动力学,并以DOX-OCC为对照,通过MTT试验对DOX-OCT-PEG-OCC胶束的抗肿瘤活性进行了评价。OCT以PEG为连接臂成功偶联于OCC的游离羧基上,该偶联产物在水介质中能自组装形成纳米胶束,对DOX具有优越的增溶效果,载药量高达35.7%,包封率为97.5%,粒径为138.8 nm,多分散系数为0.184,Zeta电位为-34.0 mV,粉末衍射试验证实DOX以无定型或分子分散状态增溶于胶束疏水内核中;DOX-OCT-PEG-OCC胶束体外释放行为呈现非零级释药特征,释放速度具有一定pH依赖性。体外细胞毒实验结果表明：DOX-OCT-PEG-OCC胶束比DOX-OCC胶束对生长抑素受体（SSTR）过度表达的人乳腺细胞MCF-7具有更强的细胞毒性,而对不表达SSTR的人胚肺成纤维细胞WI-38细胞毒性没有显著差异。结果表明:OCT-PEG-OCC是阿霉素优良的增溶和细胞主动靶向递送载体,具有良好的应用前景。     

Polymeric nanoparticles of cholesterol‐modified glycol chitosan for doxorubicin delivery: preparation and in‐vitro and in‐vivo characterization

Objectives Polymeric nanoparticles have been extensively studied as drug carriers. Chitosan and its derivatives have attracted significant attention in this regard but have limited application because of insolubility in biological solution. In this work, we attempted to utilize cholesterol‐modified glycol chitosan (CHGC) self‐aggregated nanoparticles to increase aqueous solubility, and to reduce side effects and enhance the antitumour efficacy of the anticancer drug doxorubicin. Methods CHGC nanoparticles were loaded with doxorubicin by a dialysis method, and their characteristics were determined by transmission electron microscopy examination, light‐scattering study, in‐vitro drug‐release study, pharmacokinetic study in rats and in‐vivo antitumour activity in mice. Key findings The resulting doxorubicin‐loaded CHGC nanoparticles (DCNs) formed self‐assembled aggregates in aqueous medium. From the observation by transmission electron microscopy, DCNs were almost spherical in shape. The mean diameters of these nanoparticles determined by dynamic light scattering were in the range of 237–336 nm as the doxorubicin‐loading content increased from 1.73% to 9.36%. In‐vitro data indicated that doxorubicin release from DCNs was much faster in phosphate‐buffered saline at pH 5.5 than at pH 6.5 and 7.4, and the release rate was dependent on the loading content of doxorubicin in these nanoparticles. It was observed that DCN‐16 (drug loaded content: 9.36%) exhibited prolonged circulation time in rat plasma and showed higher antitumour efficacy against S180‐bearing mice than free doxorubicin. Conclusions These results indicated that CHGC nanoparticles had potential as a carrier for insoluble anticancer drugs in cancer therapy.     

Improving the therapeutic index of anthracycline chemotherapy: Focus on liposomal doxorubicin (Myocet™)

Anthracyclines are valuable cytotoxic agents in cancer treatment. However, their usefulness is limited by cumulative dose-dependent cardiotoxicity that may manifest as life-threatening congestive heart failure. To avoid cardiotoxicity, the use of doxorubicin is typically capped at a safe cumulative dose. Liposomal formulations may reduce cardiac risks whilst maintaining anti-cancer efficacy.Efficacy and safety studies of non-pegylated liposomal doxorubicin (NPLD) in metastatic breast cancer (MBC) are reviewed, along with studies that examine efficacy and cardiac tolerability in combination with newer agents such as paclitaxel and trastuzumab. These show that cardiac safety of liposomal doxorubicin is similar to that of epirubicin in cumulative dose, but that the formulation, unlike epirubicin, has similar anti-cancer efficacy to doxorubicin at equimolar doses. Liposomal doxorubicin may have a better therapeutic index than non-liposomal anthracyclines. This justifies further studies in patients where cumulative cardiotoxicity is a concern, as does study of its use with other potentially cardiotoxic agents.     

Anthracycline-induced cardiotoxicity: Overview of studies examining the roles of oxidative stress and free cellular iron

The risk of cardiotoxicity is the most serious drawback to the clinical usefulness of anthracycline antineoplastic antibiotics, which include doxorubicin (adriamycin), daunorubicin or epirubicin. Nevertheless, these compounds remain among the most widely used anticancer drugs. The molecular pathogenesis of anthracycline cardiotoxicity remains highly controversial, although the oxidative stress-based hypothesis involving intramyocardial production of reactive oxygen species (ROS) has gained the widest acceptance. Anthracyclines may promote the formation of ROS through redox cycling of their aglycones as well as their anthracycline-iron complexes. This proposed mechanism has become particularly popular in light of the high cardioprotective efficacy of dexrazoxane (ICRF-187). The mechanism of action of this drug has been attributed to its hydrolytic transformation into the iron-chelating metabolite ADR-925, which may act by displacing iron from anthracycline-iron complexes or by chelating free or loosely bound cellular iron, thus preventing site-specific iron-catalyzed ROS damage. However, during the last decade, calls for the critical reassessment of this “ROS and iron” hypothesis have emerged. Numerous antioxidants, although efficient in cellular or acute animal experiments, have failed to alleviate anthracycline cardiotoxicity in clinically relevant chronic animal models or clinical trials. In addition, studies with chelators that are stronger and more selective for iron than ADR-925 have also yielded negative or, at best, mixed outcomes. Hence, several lines of evidence suggest that mechanisms other than the traditionally emphasized “ROS and iron” hypothesis are involved in anthracycline-induced cardiotoxicity and that these alternative mechanisms may be better bases for designing approaches to achieve efficient and safe cardioprotection.     

Genotoxic effects of aluminum chloride in cultured human lymphocytes treated in different phases of cell cycle.

Aluminum (Al) is the most abundant metal and the third common chemical element on earth. It is known that Al is toxic, especially its trivalent form (Al(3+)), that represents the its most soluble form. Al intoxication is related to some pathogenic disorders, principally neurodegeneratives ones as Parkinson and Alzheimer diseases. The present study aimed to evaluate the mutagenic potential of aluminum chloride (AlCl(3)). Comet assay and chromosome aberrations analysis were applied to evaluate the DNA-damaging and clastogenic effects of AlCl(3), respectively, in different phases of the cell cycle. Cultured human lymphocytes were treated with 5, 10, 15 and 25 microM aluminum chloride during the G1, G1/S, S (pulses of 1 and 6h), and G2 phases of the cell cycle. All tested concentrations were cytotoxic and reduced significantly the mitotic index in all phases of cell cycle. They also induced DNA damage and were clastogenic in all phases of cell cycle, specially in S phase. AlCl(3) also induced endoreduplication and polyploidy in treatments performed during G1 phase. The presence of genotoxicity and polyploidy on interphase and mitosis, respectively, suggests that aluminum chloride is clastogenic and indirectly affects the construction of mitotic fuse in all tested concentrations.     

Use of the Post-Insertion Technique to Insert Peptide Ligands into Pre-Formed Stealth Liposomes with Retention of Binding Activity and Cytotoxicity

Purpose: Simple methods for the large-scale manufacture of ligand-targeted liposomes will be needed if clinical trials are to proceed. We tested a recently developed technology for inserting peptide ligands into preformed Stealth liposomes. Antagonist G-targeted liposomes (PLG) were prepared and loaded with doxorubicin and their cellular association and cytotoxicity were evaluated using the human small cell lung cancer H69 cell line. Methods: The hexapeptide antagonist G was covalently coupled via a thioether bond to the terminus of polyethylene glycol (PEG) in micelles formed from maleimide-derivatized poly(ethylene glycol) (M_r 2000) distearoylphosphatidylethanolamine followed by transfer into preformed liposomes during a one-step incubation. For cellular association, we used radiolabeled liposomes. Cytotoxicity was evaluated using the MTT in vitro proliferation assay. Results: The postinsertion approach to the formation of peptide-targeted liposomes led to the production of PLG bearing a maximum of approximately 0.3 g antagonist G/mol phospholipid. These liposomes had increased cellular association to H69 cells relative to nontargeted liposomes and, when loaded with doxorubicin, they resulted in similar levels of cytotoxicity to those obtained by conventional coupling techniques. Conclusions: The postinsertion technique is a simple, effective means for the production of biologically active peptide-targeted liposomes.     

鬼桕酰肼自旋标记衍生物的抗氧化活性

目的:研究鬼桕酰肼自旋不达意标记衍生物的抗氧化活性及其结构活性关系.方法:用TBA比色法测自发性生成或Fe~(2 )-抗坏血酸和多柔比星刺激大鼠心、肝、肾组织匀浆生成的MDA;用分光光度法测H_2O_2诱导的大鼠RBC溶血反应;用NBT还原法测大鼠活化中性粒细胞超氧阴离于生成.结果:GP1、GP10H明显抑制MDA生成,对抗H_2O_2诱导的溶血反应,而GP和GP1H作用微弱,GP1尚抑制超氧阴离子生成.结论:氮氧自由基引入GP中,使其衍生物抗氧化作用大大增强,必需活性基因为NO基和NOH基.