海南哥纳香醇甲(GHM-10)对L1210细胞生物大分子合成的抑制作用

目的旨在研究GHM-10对L1210细胞生物大分子合成的影响。用[³H]标记前体参入试验。结果表明,GHM-104～12μg·ml^-1作用6h,可使L1210细胞的DNA,RNA及蛋白质的生物合成发生明显抑制,其中以抑制DNA合成的作用最强。用[³H]TdR参入曲线法、紫外吸收光谱移动法和荧光光谱移动法研究了GHM-10抑制DNA生物合成的机制。结果表明,GHM-10 6～8μg·ml^-1作用L1210细胞1h后,DNA合成的抑制已不可逆。提示GHM 10可能引起DNA分子结构的损伤,但GHM-10不能嵌入DNA分子或直接破坏DNA的结构。     

海南哥纳香醇甲GHM-10对L1210细胞DNA分子结构及拓扑异构酶II活性的影响

目的： 研究海南哥纳香醇甲（GHM-10）抑癌细胞DNA合成的作用机制。 方法： 用单细胞凝胶电泳法检测GHM-10对L1210细胞DNA分子的损伤,碱洗脱法测定GHM-10对L1210细胞DNA单链长度的影响,用GHM-10对超螺旋pUC18 DNA的解旋能力测定它对DNA拓扑异构酶II活性的影响。 结果： L1210细胞用GHM-10 (4～10) μg.ml^-1处理4.5 h后,DNA分子受损,表现为电泳后在荧光显微镜下可见彗星状拖尾。GHM-10 (4～25) μg.ml^-1处理L1210细胞5 h, 可引起DNA单链断裂。 L1210细胞或从L1210细胞分离的蛋白质在用GHM-10处理后,DNA拓扑异构酶II的活性均被抑制。结论： GHM-10可引起L1210细胞DNA分子损伤; 无论在细胞内还是细胞外,GHM-10可抑制拓扑异构酶II的活性。     

从海南哥纳香中分离的一种新化合物──海南哥纳香醇甲的抗肿瘤作用

体外用细胞生长曲线测定法、MTT试验、软琼脂集落形成分析法,及体内对移植性肿瘤实验,研究了海南哥纳香醇甲(GHM-10)的抗肿瘤作用,结果表明:GHM-10对肿瘤细胞有较强的抑制作用,IC₅₀在2μg·ml^-1左右;对正常细胞影响较小,骨髓祖细胞的敏感性则更低;耐药的KB/VCR200细胞及其亲本KB细胞具有相似的敏感性。GHM-10对HL-60细胞无分化诱导作用。GHM-10对实体型肝癌H22小鼠、Lewis肺癌小鼠及腹水型S180小鼠均有明显的治疗作用。     

人参皂甙Rh2体外对小鼠黑色素瘤细胞的分化诱导作用

体外实验证明人参皂甙Rh₂在10μg·ml^-1的浓度下能明显抑制B₁₆细胞的生长,并呈浓度依赖性,其IC₅₀为4.1μg·ml^-1。Rh₂在10μg·ml^-1浓度下对B₁₆细胞有较强的分化诱导作用,表现为黑色素生成能力明显增加;形态向上皮样细胞分化;细胞呈网状结构;黑色素颗粒增多,生长变缓慢。细胞动力学研究结果表明,Rh₂可使B₁₆细胞阻断在G₁期。提示Rh₂对B₁₆细胞具有分化诱导作用。     

二甲双胍缓释片人体药代动力学及其相对生物利用度

目的 研究国产盐酸二甲双胍缓释片在人体药代动力学行为并与普通片进行等效性评价比较,并估算其药代动力学参数。方法 20名受试者分两组交叉服用缓释片和普通片,用RP-HPLC法测定血浆中药物浓度,并估算相应的药动学参数。结果 单剂量口服1000mg缓释片和普通片后估算的AUC_0-24分别为11.95±2.62μg·h^-1·ml^-1和10.72±2.23μg·h^-1·ml^-1;C_max分别为1.50±0.22μg·ml^-1和2.34±0.30μg·ml^-1;T_max分别为3.38±0.8h和1.61±0.32h;t_1/2分别为4.94±0.47h和3.20±0.38h;多剂量1000mg·d^-1时AUC_ss分别为15.04±3.01μg·h^-1·ml^-1和14.51±2.69μg·h^-1·ml^-1;C_max分别为1.68±0.25μg·ml^-1和1.60±0.26μg·ml^-1;C_min分别为0.15±0.03μg·ml^-1和0.12±0.04μg·ml^-1;Cav分别为0.62±0.13μg·ml^-1和0.61±0.11μg·ml^-1;T_max分别为3.61±0.60h和1.88±0.38h;AUC_0-24和AUC_ss经对数转换后方差分析和双单侧t检验，显示两制剂吸收程度生物等效。结论受试制剂和参比制剂吸收程度生物等效，但具有缓释特性。盐酸二甲双胍缓释片的相对生物利用度单剂量时为（111.5±8.3）%，多剂量时为（103.6±9.2）%。     

海南粗榧新碱衍生物HH07A的抗肿瘤作用

用细胞生长曲线测定法及软琼脂集落形成分析法研究了HH07A对几种肿瘤及正常细胞生长的影响。结果表明,1.5ug·ml^-1及3μg·ml^-1HH07A能分别明显抑制L1210和HL-60细胞的生长。3种肿瘤细胞对HH07A的敏感性依次为L1210>KB>HL-60,而正常小鼠粒系祖细胞GM-CPC对药物的敏感性则低于前三者,且HH07A3.5μg·ml^-1对HL-60细胞无分化诱导作用。HH07A对腹水型L1210白血病小鼠、S180小鼠均有较明显的治疗作用,使L1210荷瘤小鼠、S180荷瘤小鼠存活时间延长。也能抑制S180实体瘤的生长。     

环孢菌素A阻断人HL-60抗药性细胞于G1期而诱导敏感细胞凋亡

进一步研究了抗三尖杉酯碱的HL-60细胞(HR20)抗细胞凋亡的机制及该抗性和抗药性的关系。结果表明,环孢菌素A(CsA)20,10μg·ml^-1诱导HL-60细胞发生凋亡,而阻断HR20细胞于G₁期,就不能诱导细胞发生凋亡。低浓度的CsA明显增加柔红霉素在HR20细胞内的积聚,其逆转抗药性作用与阻断细胞周期运行无关。CsA10μg·ml^-1处理HR20细胞,可引起50kDa的蛋白质高度磷酸化。结果提示:环孢菌素A阻断抗三尖杉酯碱的HL-60细胞于G₁期,而诱导敏感的HL-60细胞发生凋亡,其阻断作用与抗药性无关。     

商陆多糖Ⅰ联合白细胞介素2对小鼠脾细胞杀瘤活性的影响

商陆多糖Ⅰ(PAP-I),0.3～3μg·ml^-1和小鼠脾细胞培养3～5d可显著增强其杀伤P815肿瘤细胞活性及IL-2(250～500IU·ml^-1)诱导的LAK细胞活性,最适浓度为1μg·ml^-1。PAP-I及IL-2和脾细胞培养的上清液对P815肿瘤细胞无细胞毒作用,但能增强脾细胞及LAK细胞杀瘤活性。PAP-I,5,10及50mg·kg-1,ip可增强脾细胞杀伤P₈₁₅和L₉₂₉细胞的活性及IL-2诱导的LAK细胞活性。     

海南粗榧新碱衍生物HH07A对体外L1210细胞的杀伤作用

体外培养的小鼠L1210细胞被HH07A2μg·ml^-1作用24h后,与对照组细胞相比,其细胞数不再增长,有丝分裂数及集落形成率下降,细胞形态及细胞周期动力学均发生一定的变化。且HH07A大剂量短期作用抑制Ll210细胞集落形成的效率高于低剂量持续作用。     

应用薄层扫描研究大鼠一次口服硝硫苯酯的药代动力学

本文建立了血浆中硝硫苯酯TLC扫描定量法,并可同时测定血浆中代谢物硝硫氰胺浓度。该法专一、灵敏。大鼠单剂ig硝硫苯酯200mg/kg后,血浆硝硫苯酯C_max为0.510μg.ml^-1,t_max为6 h,药—时曲线符合二室模型。t1/2ka,t1/2a、t1/2β分别为1.503,2.829和17.769 h;k₁₀,k₂₁和k₁₂分别为0.068,0.141和0.075h^-1,∫₀^∞cdt为12.367μg·h·ml^-1。本文还证明硝硫苯酯在吸收后,有部分转变为硝硫氰胺,其C_max为0.283μg·ml^-1,t_max为6 h。硝硫苯酯和硝硫氰胺曲线下∫₀³⁶cdt分别为9.211和4.644μg·h·ml^-1,后者约为前者的50%。     

Anticancer effect of Howiinol A and its mechanism of action

Howiinol A (GHM-10) is a kind of phenylethylene pyrone compounds isolated from Goniothalamus howii. By using the techniques of cell growth curve determination, MTT test, soft agar colony assay and experimental therapy of transplantable tumors in mice, it is found that GHM-10 exerts potent inhibitory effect on cancer cells but its influence on normal cells is relatively slight; the sensitivity of a drug-resistant cell line, KB/VCR 2000, to GHM-10 is similar to its parent cell line KB. Remarkable therapeutic effect can be seen in mice bearing H22 hepatoma and Lewis lung cancer and in mice with ascetic sarcoma 180 when GHM-10 is orally or intraperitoneally administered.

The IC₅₀s of L1210 cells treated with GHM-10 for 1 and 24 h are 6.85 and 3.32 μg·ml^-1 respectively. The ratio of IC₅₀ 1 h and IC₅₀ 24 h is only 2.06, indicating that the action of GHM-10 is conformed to a cell cycle non-specific cytotoxic agent. By using trypan blue exclusive test and morphological examination, it is demonstrated that the main effect of GHM-10 is to inhibit the cell proliferation. Flow cytometery technique is used to analyze the cell cycle of L1210 cells. The results show that to some extent, GHM-10 blocks the cell cycle transition from G1 phase to S phase. By using [³H] labeled precursor incorporation technique, it is shown that GHM-10 significantly suppresses the biosynthesis of DNA, RNA and protein in L1210 cells, and the DNA synthesis is mostly affected. At 1 h after the cells were treated with GHM-10, these inhibitory effects have already been irreversible, suggesting that GHM-10 may cause structural damage on DNA molecules. However, GHM-10 is unable to intercalate into DNA molecules or to destroy its structure directly. By using single cell gel electrophoresis and alkaline elution technology, it is confirmed that GHM-10 causes DNA molecule damage and single strand breakage in L1210 cells. Further studies show that GHM-10 markedly inhibits DNA dehelix induced by DNA topoisomerase II both inside and outside the cells, indicating that GHM-10 is acting as an inhibitor of DNA topoisomerase II.     

2-乙氧甲酰亚甲基-4-氰基-5,6-二苯哒嗪-3-酮对L1210细胞周期的影响

本文研究了哒嗪(DPP)衍生物PD032对L1210细胞周期移行的影响。结果表明,PD032(2～10μmol/L)作用24h,G_1期细胞明显减少,G_2+M期细胞增加5～10倍。同时观察到有丝分裂指数增加,细胞体积增大及多核现象。S期在高浓度(10μmol/L)PD032时有减少,这时[~3H]TdR参入DNA也有轻度抑制。洗去药物后24～48h,上述变化有不同程度的恢复。以上结果说明PD032是有丝分裂抑制剂。     

In vitro and in vivo antitumoral activity of free, and encapsulated taxol

The anti-tumoral activity of taxol encapsulated either in liposomes or in nanocapsules was compared with that of free taxol, using the P388 and L1210 leukaemia test systems. The in vitro inhibition of cell growth was measured after 48 h and 96 h exposure to various concentrations of taxol. With P388 cells, the inhibitory activities of the three forms of the drug were similar. With the L1210 cells, however, the concentrations required for a 50 per cent inhibition of cell growth (IC50) after 48 h exposure to the drug were greater for nanocapsules than for liposomes or free taxol, the values being 0.060, 0.043 and 0.035 micrograms ml-1, respectively. However, a greater efficiency of nanocapsules was observed after 96 h exposure. Using cytomorphometric analysis, no difference was found between L1210 cells treated either with free or encapsulated taxol. In vivo, mice bearing P388 leukaemia, and treated either with taxol solubilized with 5 per cent DMSO + 5 per cent cremophor in saline solution, or with taxol encapsulated in liposomes (IP daily dose of 12.5 mg Kg-1 body weight x 4 days) showed ILS values of 65.8% and 67.9% respectively. Nanocapsules proved to be toxic, apparently due to their composition: this problem is currently under investigation.     

Cytocidal action of homoharringtonine on L1210 cells in vitro

The proliferation of L 1210 cells ceased rapidly after they were exposed to homoharringtonine (HH) 1 microgram/ml during exponential growth phase. However, 25.3% of the cells were still able to form colonies in soft agar if HH was removed after 24 h of incubation (the colony-forming efficiency for control cells was 62.5%). The clonogenic cells survived from the treatment were still sensitive to HH-continuous exposure. The IC50 of the treated and control cells were 15 and 20 ng/ml, respectively. Yet, the sensitivity of the treated cells to cytarabine decreased enormously. For instance, the survival rate of HH-treated cells remained at 100% level after they were exposed to cytarabine 4-8 micrograms/ml for 1 h, but only 40% control cells survived from the same treatment. When cells were continuously exposed to HH 0.4 micrograms/ml, the colony-forming efficiency decreased exponentially as a function of exposure time. The T1/2 of the clonogenic cells was about 18 h. The DNA contents in L 1210 cells was measured with a flow-cytometer. The results showed that the cell-cycle progress in all cells was interrupted by HH, regardless which phase they belonged to. So the cells seemed to be in a "frozen" state and the histogram unchanged.     

Effect of berberine on proliferation,cell cycle and apoptosis in HeLa and L1210 cells

Previous studies on the anticancer activity of protoberberine alkaloids against a variety of cancer cell lines were extended to human tumour HeLa and murine leukemia L1210 cell lines. An attempt was also made to investigate the relationship between the cytotoxic activity of berberine and its molecular mechanism of action. Cytotoxicity was measured in-vitro using a primary biochemical screening according to Oyama and Eagle, and the growth inhibition assay. The in-vitro cytotoxic techniques were complemented by cell cycle analysis and determination of apoptotic DNA fragmentation in L1210 cells. Berberine acted cytotoxically on both tumour cell lines. The sensitivity of leukemia L1210 cells to the berberine was higher than that of HeLa cells. The IC(100) was below 100 microg mL(-1) for HeLa cells and approached a 10 microg mL(-1) limit for the leukemia L1210 cells. For both cell lines the IC(50) was found to be less than 4 microg mL(-1), a limit put forward by the National Cancer Institute (NCI) for classification of the compound as a potential anticancer drug. In L1210 cells treated with 10-50 microg mL(-1) berberine, G(0)/G(1) cell cycle arrest was observed. Furthermore, a concentration-dependent decrease of cells in S phase and increase in G(2)/M phase was detected. In addition, apoptosis detected as sub-G(0) cell population in cell cycle measurement was proved in 25-100 microg mL(-1) berberine-treated cells by monitoring the apoptotic DNA fragmentation (DNA ladder) using agarose gel electrophoresis.     

Inhibition of inducible nitric oxide synthase expression by novel nonsteroidal anti-inflammatory derivatives with gastrointestinal-sparing properties.

1. The effects of novel nitric oxide-releasing nonsteroidal anti-inflammatory compounds (NO-NSAIDs) on induction of nitric oxide (NO) synthase by bacterial lipopolysaccharide (LPS) were examined in a murine cultured macrophage cell line, J774. 2. LPS-induced nitrite production was markedly attenuated by the nitroxybutylester derivatives of flurbiprofen (FNBE), aspirin, ketoprofen, naproxen, diclofenac and ketorolac, with each compound reducing accumulated nitrite levels by > 40% at the maximum concentrations (100 micrograms ml-1) used. 3. Further examination revealed that nitrite production was inhibited in a concentration-dependent (1-100 micrograms ml-1) manner by FNBE which at 100 micrograms ml-1 decreased LPS-stimulated levels by 63.3 +/- 8.6% (n = 7). The parent compound flurbiprofen was relatively ineffective over the same concentration-range, inhibiting nitrite accumulation by 24 +/- 0.9% (n = 3) at the maximum concentration used (100 micrograms ml-1). 4. FNBE reduced LPS-induced nitrite production when added to cells up to 4 h after LPS. Thereafter, FNBE caused very little or no reduction in nitrite levels. Furthermore NO-NSAIDs (100 micrograms ml-1) did not inhibit the metabolism of L-[3H]-arginine to citrulline by NO synthase isolated from LPS-activated macrophages. 5. Western blot analysis demonstrated that NO synthase expression was markedly attenuated following co-incubation of J774 cell with LPS (1 microgram ml-1; 24 h) and FNBE (100 micrograms ml-1; 24 h). Thus taken together, these findings indicate that NO-NSAIDs inhibit induction of NO synthase without directly affecting enzyme activity. 6. In conclusion our results indicate that NO-NSAIDs can inhibit the inducible L-arginine-NO pathway, and are capable of suppressing NO synthesis by inhibiting expression of NO synthase. The clinical implications of these findings remain to be established.     

Effect of anti-fungal imidazoles on mRNA levels and enzyme activity of inducible nitric oxide synthase.

1. Experiments were performed to examine the effects of anti-fungal imidazole compounds (clotrimazole, econazole and miconazole) on the induction of nitric oxide (NO) synthase and subsequent production of NO in the cultured murine monocyte/macrophage cell line J774 using a specific cDNA probe for inducible NO synthase mRNA and by monitoring nitrite production. 2. Stimulation of J774 cells with lipopolysaccharide (LPS, 10 micrograms ml-1) resulted in the induction of NO synthase activity as determined by nitrite accumulation in the culture medium (48 +/- 3 nmol per 10(6) cells over 24 h). Production of nitrite was inhibited by co-incubation of cells with LPS (10 micrograms ml-1) and either dexamethasone (10 microM) or NG-monomethyl-L-arginine (L-NMMA; 0.1 mM), however, only L-NMMA was an effective inhibitor of nitrite production when added after induction of NO synthase had occurred. 3. Co-incubation of J774 cells with LPS (10 micrograms ml-1) and either clotrimazole, econazole or miconazole (1-10 microM) resulted in a concentration-dependent inhibition of nitrite production over the subsequent 24 h without any evidence for a cytotoxic effect. However, addition of these imidazoles after induction of NO synthase did not inhibit nitrite production. 4. Messenger RNA for inducible NO synthase was not detected in unstimulated J774 cells. Treatment with LPS (10 micrograms ml-1) for 4 h resulted in significant expression of mRNA for inducible NO synthase which was not altered in the presence of econazole (10 microM) but was reduced significantly by dexamethasone (10 microM).(ABSTRACT TRUNCATED AT 250 WORDS)