In vitro cytotoxicity of berberine against HeLa and L1210 cancer cell lines

Previous studies on anti-cancer activity of protoberberine alkaloids against a variety of cancer cell lines were extended to human uterus HeLa nad murine leukemia L1210 cell lines. Cytotoxicity was measured using in vitro techniques and cell morphology changes were examined by light microscopy in both cytostatic and cytocidal concentration ranges. The IC50 was found to be less than 4 microg/ml, a limit put forward by NCI for classification of the compound as a potential anti-cancer drug. The microscopy examination indicated that at cytocidal concentrations the HeLa and L120 cells died apoptotically. The comparative analysis revealed that berberine belongs to the camptothecin family of drugs characterized by the ability to induce DNA topoisomerase poisoning and hence apoptotic cell death. Although the cytotoxic potency of berberine was found to be several orders of magnitude lower compared to camptothecin, its significance may increase in future in view of the lack of unwanted side effects characteristic for camptothecin compounds currently in clinical use for treatment of cancer.     

Cytotoxic activity of the selected pyridinium salts against murine leukemia L1210

The objective of this work was to evaluate the relationship between chemical reactivity of 3-substituted pyridinium salts and their cytotoxic properties against murine leukemia L1210. Chemical reactivity of pyridinium salts towards NADH oxidation following one-step hydride transfer depends strongly on their redox properties. The investigated reaction may reflect the ability of the salts to deplete NADH level in cells and to affect their metabolic functions. On the other hand, the cytotoxic activity against murine leukemia cells, expressed as ED50 values, varied strongly depending upon the compound used. The investigated salts showed also a diverse antileukemic effect in in vivo experiments as measured by the increase in the survival time of L1210 leukemia-bearing mice. These biological effects were correlated with equilibrium constants found for the reaction of pyridinium salts with NADH.     

Antineopastic natural products and the analogues IV. Aurapten,the cytotoxic coumarin fromPoncirus trifoliata against L1210 cell

A cytotoxic coumarin against L1210 cell was isolated from the unripe fruit ofPoncirus trifoliata (ED₅₀=10.2 μg/ml). Its structure was identified as aurapten, 7-geranyloxycoumarin. Hydrolysis of the substance gave umbelliferone and geraniol. Only geraniol showed the cytotoxic activity (ED₅₀=6.5 μg/ml) while umbelliferone and its methyl or allyl derivatives were not active.     

Alkaloids from Lycoris caldwellii and their particular cytotoxicities against the astrocytoma and glioma cell lines

Phytochemical investigation of the ethanol extract of the bulbs of Lycoris caldwellii afforded four new alkaloids, (+)-N-methoxylcarbonyl-nandigerine (1), (+)-N-methoxycarbonyl-lindcarpine (2), (+)-10-O-methylhernovine N-oxide (3), and (+)-3-hydroxy-anhydrolycorine N-oxide (4). Structural elucidation of all the compounds were performed by spectral methods such as 1D and 2D (¹H-¹H COSY, HMQC, and HMBC) NMR spectroscopy, in addition to high resolution mass spectrometry. All the alkaloids were in vitro evaluated for their cytotoxic activities against eight tumor cell lines (BEN-MEN-1, CCF-STTG1, CHG-5, SHG-44, U251, BGC-823, HepG2, and SK-OV-3). Alkaloids 1 and 2 exhibited particular cytotoxic activities against astrocytoma and glioma cell lines with IC₅₀ of 9.2–11.3 μM and 10.4–12.2 μM respectively.     

Inhibitory activity of diarylamidine derivatives on murine leukemia L1210 cell growth

Summary A series of 96 diarylamidine (and diarylimidazoline) derivatives were evaluated for their inhibitory effects on the growth and DNA synthesis of murine leukemia L1210 cells. The amidino- and imidazolino-substituted aryl moieties of the compounds consisted of phenyl, indole, indene, benzofuran, benzo[b]thiophene or benzimidazole. Several of these compounds were found to inhibit L1210 cell proliferation with an ID₅₀ (50% inhibitory dose) of 1 g/ml or lower. Structure-function analysis revealed that the antitumor cell activity of the diarylamidines depended on the planarity of the molecule, the presence of amidino- (or, preferably, imidazolino-) groups on both aryl moieties, the nature of the bridge connecting the two aryl moieties (preferably no bridge at all, phenoxy or ethene) and, finally, the nature of the aryl moieties (preferably, benzofuran or benzo[b]thiophene). Hence, compound 20 (6-(2-imidazolin-2-yl)-2-[4-(2-imidazolin-2-yl)phenyl] benzo[b]thiophene) emerged as the most potent inhibitor of L1210 cell growth (ID₅₀: 0.21 g/ml). Its inhibitory potency was similar to that of the well-known trypanocidal drug ethidium bromide (compound 98). For all diarylamidine derivatives taken together, some correlation (r = 0.612) was noted between the log ID₅₀ for L1210 cell proliferation and the log ID₅₀ for L1210 cell DNA synthesis (as monitored by [methyl ³H]dThd incorporation). These findings suggest that the inhibitory effects of the diarylamidines on L1210 cell proliferation may at least partially reside in an inhibition of DNA synthesis. Compound 41 (2,2-vinylenedi-1-benzofuran-5-carboxamidine), that exhibited a potent antitumor activity in vitro (ID₅₀: 1.5 g/ml), was further evaluated for its antitumor efficacy in vivo and found to increase the median survival time of L1210 cell-inoculated BDF₁ mice up to 204%, if administered at a dose of 200 mg/kg.     

Basic fibroblast growth factor enhanced LAK cell cytotoxicities against human bladder neoplasm cells 1

目的：探讨白细胞介素Ⅱ（ＩＬ２）和碱性成纤维细胞生长因子（ｂＦＧＦ）对膀胱癌患者淋巴因子激活的杀伤细胞（ＬＡＫ细胞）的作用．方法：用细胞计数观察不同浓度ｂＦＧＦ对ＬＡＫ细胞增殖的影响．以膀胱癌细胞系ＥＪ及新鲜分离患者自体肿瘤细胞（ＢＴＣ）为靶细胞,用ＭＴＴ法测定ＬＡＫ细胞对膀胱癌细胞的细胞毒作用．结果：虽然外周血单核细胞（ＰＢＭＣ）的增殖可被ｂＦＧＦ５μｇ·Ｌ－１所抑制,ＩＬ２所诱导的ＬＡＫ细胞的增殖却不受ｂＦＧＦ的影响,ｂＦＧＦ明显加强ＬＡＫ对ＥＪ细胞和ＢＴＣ的细胞毒作用．结论：虽然ｂＦＧＦ抑制ＰＢＭＣ的增殖,但ｂＦＧＦ又增强膀胱癌患者ＬＡＫ细胞对肿瘤细胞的细胞毒性．     

Studies on the mechanism of spironolactone protection against indomethacin toxicity

Pretreatment of rats for 4 days with spironolactone (75 mg/kg) increases the LD50 of indomethacin from 13 (12.7–14.5) mg/kg ip to 37 (34–41) mg/kg ip. In an attempt to determine the mechanism by which spironolactone decreases the toxicity of indomethacin, [¹⁴C]indomethacin (8 mg/kg) was administered ip to control and spironolactone-pretreated rats and the concentration of ¹⁴C in various tissues was determined at timed intervals up to 4 hr. The concentration of ¹⁴C in the tissues of the two groups 30 and 60 min after [¹⁴C]indomethacin administration were similar, but at the 2-, 3-, and 4-hr time intervals, the concentration of ¹⁴C was lower in the blood, plasma, lung, heart, spleen, and muscle of the spironolactone-pretreated rats. This indicates that spironolactone enhances the excretion of indomethacin. The mechanism of the enhanced excretion was studied using [¹⁴C]indomethacin administered iv (4 mg/kg) to control and spironolactone-pretreated rats. The amount of ¹⁴C in the plasma and bile was measured. Spironolactone markedly enhanced the plasma disappearance of ¹⁴C and more than doubled the rate of its excretion into the bile. The increased excretion of ¹⁴C into the bile of the spironolactone-pretreated rats was mostly in the form of more water-soluble metabolites. The increased plasma disappearance and biliary excretion of indomethacin is also observed after other microsomal enzyme inducers. Phenobarbital (75 mg/kg) and pregnenolone-16α-carbonitrile (75 mg/kg) produced a similar increase in the plasma disappearance and biliary excretion of indomethacin as did spironolactone, but 3-methylcholanthrene (20 mg/kg) was without effect. Thus, it appears that spironolactone decreases the toxicity of indomethacin by increasing its biotransformation and excretion into the bile.     

碱性成纤维细胞生长因子增强淋巴因子激活的杀伤细胞对人膀胱 …

目的 探讨白细胞介素Ⅱ（ＩＬ－２）和碱性成纤维细胞生长因子（ｂＦＧＦ）对膀胱癌患者淋巴因子激活的杀伤细胞（ＬＡＫ细胞）的作用。方法 用细胞计数观察不同浓度ｂＦＧＦ对ＬＡＫ细胞增殖的影响,以膀胱癌细胞系ＥＪ及新鲜分离患者自体肿瘤细胞（ＢＴＣ）为靶细胞,用ＭＴＴ法测定ＬＡＫ细胞对膀胱癌细胞的细胞毒作用,结果 虽然外周血单核细胞（ＰＢＭＣ）的增殖可被ｂＦＧＦ５μｇ．Ｌ＾－１所抑制,ＩＬ－２所诱导的ＬＡＫ     

Activity of platinum(II) intercalating agents against murine leukemia L1210

Four series of intercalating, square-planar Pt(II) complexes derived from the ligands 2,2'-bipyridine, 2,2':6',2"-terpyridine, 1,10-phenanthroline, and 3,4,7,8-tetramethyl-1,10-phenanthroline were synthesized and aspects of their activity against murine leukemia L1210 cells investigated. The 2,2':6',2"-terpyridine-thiolato complexes are growth inhibitory in culture, with IC50 values in the range 6-32 microM, and cause cell lysis at high concentrations. Of the remaining three series, the 2,2'-bipyridine complexes are the least potent in their effects. There is a general enhancement in activity on moving from the 1,10-phenanthroline complexes to the 3,4,7,8-tetramethyl-1,10-phenanthroline analogues. Flow cytometric analysis on representative complexes shows that they are not cell cycle specific. Alkaline elution experiments indicate no damage to DNA of cells exposed to (thiophenolato)(2,2':6',2"-terpyridine)platinum(II) chloride monohydrate and (ethylenediamine)(1,10-phenanthroline)platinum(II) dichloride dihydrate although (ethylenediamine)(3,4,7,8-tetramethyl-1,10-phenanthroline)platinum(II) dichloride dihydrate causes both single-strand breaks and DNA cross-links. Compounds 2a, 5a, and 6a showed no antitumor activity against L1210 in mice.     

Relation between structure and cytotoxic activity of panaxydol analogs against L1210 cells

Relation between Structure and Cytotoxic Activity of Panaxydol Analogues against L1210 Cells Panaxynol ( 2 ) and panaxytriol ( 3 ) were isolated from Panax ginseng root. The cytotoxicities of 2 and 3 were compared with that of panaxydol ( 1 ) and were correlated with partial structures comprising C-9 and C-10 in 1 – 3 .     

The effect of kazusamycin B on the cell cycle and morphology of cultured L1210 cells

The effect of a potent antitumor antibiotic, kazusamycin B, on the cell cycle of L1210 cells was examined. Kazusamycin B arrested synchronized L1210 cells at G1 phase. Retardation of metaphase initiation was also observed. Flow cytometric analysis of kazusamycin B-treated asynchronized cells also confirmed G1 arresting effect of kazusamycin B. In addition, an unidentified cell population with lower fluorescence intensity than G1 population was observed when the cells were exposed to the drug longer than 12 hours. Morphology of kazusamycin B-treated L1210 cells revealed that the intranuclear structure changed within 4 hours, and that abnormal condensation of nuclei coincided with the appearance of unidentified population. Kazusamycin B inhibited RNA synthesis moderately but specifically at 2 hours. However, this inhibition might be a secondary effect of the antibiotic-induced structural abnormality of the nuclei.     

Inhibition of ribonucleotide reductase and L1210 cell growth by N-hydroxy-N'-aminoguanidine derivatives

A series of N-hydroxy-N'-aminoguanidine derivatives was studied for their effects on L1210 cell growth and ribonucleotide reductase activity. With the twelve compounds studied, there was a good correlation between the inhibition of L1210 cell growth and the inhibition of ribonucleotide reductase activity. The most potent compound required concentrations of only 1.4 and 2 microM for 50% inhibition of L1210 cell growth and ribonucleotide reductase activity respectively. These guanidine analogs specifically inhibited the conversion of [14C]cytidine and deoxycytidine nucleotides in the nucleotide pool and the incorporation of [14C]cytidine into DNA without altering the incorporation of [14C]cytidine into RNA. Ribonucleotide reductase activity in drug-treated cells was reduced markedly. Iron-chelating agents did not either increase or decrease the inhibition caused by the N-hydroxy-N'-aminoguanidine derivatives. No evidence was obtained that these derivatives selectively inactivated one of the subunits of ribonucleotide reductase. These compounds appear to inhibit ribonucleotide reductase by a mechanism different from hydroxyurea or the thiosemicarbazone derivatives.     

Analog specific aberrancies in antifolate inhibition of L1210 cell dihydrofolate reductase

During studies with L1210 cells and a variety of folate analogs, large discrepancies were revealed between data on membrane transport, on inhibition of dihydrofolate reductase in cell-free extracts, and on inhibition of growth in culture for 10-oxa-, 10-benzyl- and 10-phenethyl-aminopterin, and for 3-deaza, 10-methyl-aminopterin. While aminopterin, 10-methyl (methotrexate)-, 10-ethyl- and 10-propyl-aminopterin were tight binding inhibitors (K_i: 2–3 × 10^?12M) of dihydrofolate reductase in cell-free extracts from L1210 cells, the other four analogs were only weak competitive inhibitors (K_i = 3–300 × 10^?8M). Similar differences among analogs were observed for inhibition of dihydrofolate reductase in cell-free extracts from Sarcoma 180 and Ehrlich cells, but not for this enzyme in microbial cell-free extracts. There were only small differences in the transport of all of the analogs by L1210 cells. Inhibition of L1210 cell growth in culture by 10-oxa-, 10-benzyl- and 10-phenethyl-aminopterin and by 3-deaza, 10-methyl-aminopterin, in contrast to the other analogs, was several orders of magnitude greater than that predicted from the data on dihydrofolate reductase inhibition. The extent of binding of 10-oxa-, 10-benzyl- and 10-phenethyl-aminopterin, and of 3-deaza and 10-methyl-aminopterin to dihydrofolate reductase in intact L1210 cells, in contradistinction to that seen for the cell-free enzyme preparations, approached that observed for methotrexate; these estimates of drug-enzyme interaction in situ were more predictive of the extent of inhibition by these analogs of L1210 cell growth in culture.     

Studies on the mechanism of paracetamol-induced protection against paracetamol hepatotoxicity.

In rats, 3 days treatment with paracetamol (1 oral dose of 1 g/kg daily) produced a complete protection against the hepatotoxic actions of a further dose of paracetamol as documented by determination of serum enzyme activities (glutamic-oxaloacetic transaminase, (GOT), glutamic-pyruvic transaminase (GPT), sorbitol dehydrogenase (SDH), bromsulphthalein retention and histological investigations. Subacute paracetamol treatment decreased liver glutathione levels by 46%, liver microsomal cytochrome P-450 content by 23%, hepatic hydroxylation of aniline by 29% and hepatic demethylation of aminopyrine by 46%. It afforded also some protection against the hepatotoxic actions of carbon tetrachloride, bromobenzene and thioacetamide, but did not influence the antiphlogistic activity of paracetamol (carrageenan paw edema test). Plasma and liver concentrations of free paracetamol after oral administration of 1 g/kg paracetamol were somewhat higher in the subacutely paracetamol-pretreated rats than in the non-pretreated control animals whereas no differences in the concentrations of conjugated paracetamol were found between the 2 groups. Pretreatment with paracetamol did not influence the urinary excretion of free paracetamol but caused some shift in the urinary excretion of paracetamol conjugates: pretreated rats excreted 23% less of the paracetamol glucuronide and sulfate and 33% more of the paracetamol mercapturate than the control animals. A depression of the microsomal mixed-function oxidase activity is presumed to be the main cause of the paracetamol-induced protection against paracetamol hepatotoxicity.