The effect of 12-alkoxy modification on the in vitro antileukaemic activity of N-methyl 2,3,8,9-tetramethoxybenzo[c]phenanthridinium salts.

Some members of a series of 12-alkyloxy benzo[c]phenanthridines are potent inhibitors of the growth of P388 tumour cells in vitro, with a strong dependence on the nature of the 12-substituent. Analogues with a quaternary nitrogen in the side chain bind strongly to DNA but are less active against the tumour cells. The multi-drug-resistant cell line Pr8/22 shows less sensitivity to the new compounds. K562 Human leukaemia cells undergo differentiation in the presence of the benzo[c]phenanthridine derivatives with a structure-activity relationship which does not correlate well with potency against the P388 cell line.

The antileukemic alkaloid fagaronine is an inhibitor of DNA topoisomerases I and II.

The antileukemic alkaloid, fagaronine, is a potent differentiation inducer of various hematopoietic cell lines. We show here that fagaronine is a DNA base-pair intercalator with a K(app) of 2.1 x 10(5) M-1 for calf thymus DNA. Fagaronine inhibits the catalytic activity of purified calf thymus topoisomerase I as shown by relaxation of supercoiled plasmid DNA followed by electrophoresis in neutral as well as in chloroquine-containing gels. The catalytic activity of topoisomerase I is inhibited at concentrations above 30 microM. Fagaronine also inhibits the catalytic activity of purified calf thymus topoisomerase II at concentrations above 25 microM as shown by decatenation of kinetoplast DNA. Fagaronine stabilizes the covalent DNA-enzyme reaction intermediate (the cleavable complex) between topoisomerase I and linear pBR322 DNA at concentrations up to 1 microM. Further increase of the fagaronine concentration leads to a progressive decrease in the cleavable complex formation, which is totally inhibited at 100 microM. In contrast, up to 1 microM fagaronine has no effect on cleavable complex formation between purified calf thymus topoisomerase II and linear pBR322 DNA, whereas cleavable complex formation is inhibited at higher concentrations. Exposure to fagaronine results in an increase in DNA-protein complex formation in intact P388 murine leukemia cells. P388CPT5 cells, which have an altered topoisomerase I activity, are 4-fold resistant to the growth inhibitory effects of fagaronine compared to the parental cell line. Similarly, DC-3F/9-OH-E Chinese hamster fibrosarcoma cells, which have an altered topoisomerase II activity, are about 5-fold resistant to the growth inhibitory effects of fagaronine. We conclude that fagaronine is an inhibitor of both DNA topoisomerase I and II and propose that this might play a role in the cytotoxic activity.

Alterations of growth fraction and DNA content in K562 cells by differentiating agents.

The growth fraction, estimated by the monoclonal antibody Ki-67 labeling, and DNA content, assessed by ethidium bromide staining, were determined simultaneously in K562 leukemic cells by flow cytometry. A multiparametric analysis enabled the fraction of the cell population with G1, S, and G2 + M contents in Ki-67-positive and Ki-67-negative cells to be evaluated. Butyric acid (BUT) was used as positive control. The fraction of Ki-positive cells decreased with the BUT concentration, while the proportion of cells with G1 DNA content increased only in the Ki-negative cells. Adriamycin, aclacinomycin A, and fagaronine induced differentiation, as assessed by benzidine staining and glycophorin A expression. These drugs decreased the fraction of Ki-positive cells by more than 50% for both anthracyclines and by 25% for fagaronine. Following treatment, Ki-negative cells displayed a G1, but also a G2 and a S DNA content in different proportions, indicating that induction of quiescent cells by differentiating agents is not a uniform process and is worthy of interest.

Isoenzymes of alkaline and acid phosphatases as bones metastasis marker in breast cancer patients.

Bone alkaline phosphatase (B-ALP) and tartrate resistant acid phosphatase (TR-ACP) are markers of osteoblastic and osteoclastic activities respectively. During a period of up to two years, these isoenzymes have been assayed in the sera of 191 breast cancer patients; 80 had bone metastases (BM). In BM bearing patients, B-ALP activity was 261 IU/l and 63 IU/l for patients without BM; TR-ACP was respectively 6.6 and 3.3 IU/l. Specificity and sensitivity were calculated according to several criteria. These isoenzyme serum levels were well correlated with those of two breast cancer markers (CEA and CA15.3) and radiograph.

Proteinuria in sickle cell trait and disease: an electrophoretic analysis.

Using ultrafiltration and SDS-PAGE, abnormal urinary protein excretion was found in 25.4% of 189 persons with sickle cell disease and trait, but none of 72 controls. Based upon molecular weight of urinary proteins, underlying renal lesions were classified as glomerular, tubular, or both. Altered protein excretion appeared at an early age, was more abnormal in older subjects, and was related to the severity of sickle cell disease (SS greater than SC = S/beta Thal greater than AS). Since none of the subjects had yet developed clinically significant renal disease, SDS-PAGE may permit early detection of patients who require careful follow-up or aggressive therapy.

Comparative effects of fagaronine, adriamycin and aclacinomycin on K562 cell sensitivity to natural-killer-mediated lysis. Lack of agreement between alteration of transferrin receptor and CD15 antigen expressions and induction of resistance to natural killer.

Little is known about membrane target antigens for natural killer (NK) cells. Transferrin receptor and CD15 antigen might be two of these target structures. A novel antileukemic alkaloid, fagaronine, is able to induce hemoglobin synthesis in the K562 cell line. Numerous reports suggest relations between the expression of natural killer target structures and the differentiation stage of malignant cells. Effects of fagaronine on the expression of glycophorin A, transferrin receptor and CD15 antigen and susceptibility to NK-mediated lysis have been investigated in K562 cells and compared to those of two anthracyclines (Adriamycin and aclacinomycin A) known to be erythroid-differentiation inducers. When comparing the balance of differentiating effect and toxicity, the dose and time-dependent effects of the drugs, fagaronine and aclacinomycin, are equivalent on K562 cells. In experimental conditions where fagaronine (3500 nM), Adriamycin (40 nM) and aclacinomycin (15 nM) recruit the same percentage of hemoglobin-containing cells (40%-50%), glycophorin A expression increases and transferrin receptor expression decreases. Only Adriamycin treatment decreases CD15 antigen expression. In addition, Adriamycin and aclacinomycin, but not fagaronine, induce resistance to NK-mediated lysis. These data suggest that (a) it is unlikely that CD15 antigen and transferrin receptor, separately considered, can be unique target structures for NK cells; and (b) fagaronine is a potent erythroid inducer which, in our system, has similar effects to aclacinomycin without induced resistance to NK attack.

Effect of fagaronine on cell cycle progression of human erythroleukemia K562 cells.

Fagaronine (Fine) is a novel antileukemic drug extracted from Fagara xanthoxyloides Lam. (Rutaceae). In an attempt to know more about its mechanism of action we describe here its inhibitory activity on cell division, 3H-thymidine incorporation and on cell cycle progression. Fine inhibits cell proliferation of K562 cells by 50% at a concentration of 3 x 10(-6) mol/l at day 4. It stimulates incorporation of labelled macromolecular thymidine on day 1, but decreases incorporation on days 2, 3 and 4. Fine induces a cell accumulation in G2 and late-S phases. This accumulation (i) increases with Fine concentration, but a complete blockade is not observed, (ii) reaches a plateau after approximately 48 h, (iii) is reversible, whereas we have previously shown that cell growth inhibition and differentiation were not reversible.

[Specific precipitation assay of bone and liver isoenzymes of serum alkaline phosphatase]. / Dosage par précipitation spécifique des isoenzymes osseux et hépatiques de la phosphatase alcaline sérique.

Wheat Germ Agglutinin (WGA) precipitates bone and biliary isoenzymes of serum alkaline phosphatase, when liver and intestinal isoenzymes remain in the supernatant. Biliary and intestinal isoenzymes--when present--are evaluated with electrophoresis. Isoenzymes content in precipitate and supernatant is studied by electrophoresis and heat-inactivation. The results of WGA technique are compared to those obtained with heat-inactivation. Heat inactivation reproducibility is poor when compared to WGA precipitation. Differences are found when data of 61 sera are studied. Since a reference method is lacking, results are correlated with other biological parameters, specific of hepato-biliary pathology, and with clinical data, such as metastasis localisation. This study shows that lectin precipitation yields more accurate results than heat-inactivation.

The antileukemic alkaloid fagaronine and the human K 562 leukemic cells: effects on growth and induction of erythroid differentiation.

In view of new antitumor compounds which could exert their therapeutic effect through a combination of cell growth inhibition and cell maturation, we describe here the effects of a novel antileukemic alkaloid, fagaronine, on the growth and the induction of hemoglobin synthesis in the K 562 cell line. We found that fagaronine, after 3 days, reduces in a concentration dependent relationship the cell growth rate without lethality and this effect on the cell growth is irreversible. Reducing the cell growth rate by 50% (IC50 = 3 X 10(-6)M) is sufficient to induce an optimal amount of hemoglobin synthesis (75% benzidine-positive cells, 13-15 pg hemoglobin/cell) after 4 days of culture. Considering the variation of the total intracellular protein content during the response, it appears that fagaronine stimulated mainly hemoglobin synthesis, and to a lesser extent non-hemoglobin proteins. These results suggest that the novel antileukemic alkaloid, fagaronine, can be considered as a potent inducer of differentiated-associated properties in the human K 562 leukemic cells.