Antitumor activity and metal complexes of the first transition series. Trans-bis(salicylaldoximato)copper(II) and related copper(II) complexes,a novel group of potential antitumor agents

The antitumor activity of forty nine different metal complexes of the first transition series against mouse leukemia L 1210 cells and of two of the complexes against Ehrlich ascites carcinoma have been tested in vitro by the method described in this paper. Eight complexes showed a 50% inhibition of tumor cell division at concentration level 5–6 μg/ml of the complex for the former and two most effective complexes also for the latter. The trans-bis-(salicylaldoximato)copper(II) and trans-bis(resorcylaldoximato)copper(II) complexes were found to possess the highest antitumor activity.     

Evidence for the occurrence of the malate-citrate shuttle in intact Ehrlich ascites tumor cells

A possible activity of the malate-citrate shuttle has been investigated in Ehrlich ascites cells by testing the effects of 1,2,3-benzenetricarboxylic acid, an inhibitor of the malate-citrate exchange, and (?)-hydroxycitrate, an inhibitor of the citrate cleavage enzyme, on the glucose-dependent oxidation-reduction rates of pyridine nucleotides and cytochrome b as well as on ATP levels of glycolyzing cells. Moreover, to quantitate such an activity, the effects of these two inhibitors have been compared with those induced under the same experimental conditions by aminooxyacetate, an inhibitor of the malate-aspartate shuttle which is known to operate in this strain of ascites tumor. Both benzenetricarboxylic acid and hydroxycitrate are able to increase the reduction of pyridine nucleotides, which follows glucose addition to whole cells, to about the same extent. A much more pronounced effect is elicited by aminooxyacetate under the same condition. When n-butylmalonate is added to slow down the flux of glycolytic reducing equivalents to the respiratory chain via the malate-aspartate shuttle, benzenetricar-boxylic acid or hydroxycitrate promotes an ATP-driven reversal of electron transfer. Indeed, the glucose-induced reduction of cytochrome b becomes sensitive to oligomycin and the ATP level is raised significantly with respect to the value of uninhibited cells. It is concluded that the malate-citrate shuttle operates in Ehrlich ascites cells, although with a substantially lower activity with respect to the malate-aspartate shuttle.     

Antitumor complexes of platinum with carrier molecules. 2 [1]. Mixed complexes of amino acids and tert-butylamine

In the search for a fine modulation of cisplatin analogues we have synthesized complexes with two different inert ligands bound to platinum in the cis- position. This paper reports on compounds of formula cis-[PtCl₂(aaH)(tba)] (aaH, amino acid; tba, tert-butylamine). These complexes have been synthesized with the aim of obtaining liposoluble cisplatin analogues bound to natural carrier groups. The derivatives of glycine, D-alanine, L-threonine, and L-serine were found to be moderately active against murine P388 and L1210 leukemia models. The compound K[PtCl₃(tba)] was also found to be active against the same tumor models. Their activity and potency was, however, much lower than that of cisplatin.     

Structure-antitumour activity relationships for new platinum complexes

Fourteen platinum (Pt) coordination complexes with different ligands, which include both Pt(II) and Pt(IV) complexes, were prepared, characterized and tested for their in vitro cytotoxic effects on KB cells and for their antitumour activity against some tumour systems (L1210 and P388 leukaemia, ADJ/PC6A plasma cell tumour and Yoshida sarcoma).The majority of the ligands were derivatives of aniline or pyridine, but complexes with tranylcypromine, guanethidine and octodrine were also synthetized.Depending on cytotoxicity the Pt-compounds could be divided into 3 groups. The compounds with a high cytotoxicity (ED₅₀ = 0.1–1 μg/ml) were also active against L1210 and P-388 leukaemia; a correlation between cytotoxicity and antitumour activity was not always observed.In these complexes the oxidation state of the Pt appears to be critical for their activity.     

Phospholipid metabolism in Ehrlich ascites tumor cells. I. Turnover rate of phosphatidylinositol.

1. Radioactive precursors, 32 PI, [1-14C]glycerol, and [1-14C]acetate, were individually injected into the peritoneal cavity of mice bearing Ehrlich ascites tumor, and the rates of incorporation into phospholipid fraction of Ehrlich ascites tumor cells were estimated. Although no distinct difference in specific activities was observed between phosphatidylinositol and other phospholipid classes as regards the incorporation of [1-14C]acetate of [1-14C]glycerol, a higher rate of incorporation of 32Pi into phosphatidylinositol was observed. The specific activity of phosphatidylinositol reached more than ten times that of phosphatidylcholine in the first hour. 2. The radioactivities incorporated into the phospholipids of Ehrlich ascites tumor cells and liver were estimated after simultaneous injection 32Pi and [2-3H]inositol. The incorporation of 32Pi into phosphatidylinositol of liver was similar in specific activity to those of other phospholipids. The ratio (3H/32Pi) of phosphatidylinositol only slightly in the ascites tumor cells, while an appreciable decrease of the ratio was observed in the liver during the first 3 hr. 3. These results suggest that phosphatidylinositol synthesis through pathways other than de novo synthesis is rapid in ascites tumor cells.     

Direct binding studies do not support the existence of true alpha-adreno-receptors in rat white fat cells

The complexity of mitochondrial translation products in mouse liver and Ehrlich ascites tumor cells have been studied using a mitoplast system active in ³⁵S methionine incorporation. Electrophoretic analysis on gradient polyacrylamide-SDS gels and urea-SDS gels under highly dissociating conditions show that both of the mitochondrial systems synthesize about 22 polypeptides. Many of these ³⁵S labeled products compare with the polypeptides predicted by the DNA sequence analysis data reported by Anderson $\text{et al.}$ (1).     

Synthesis of 8-hydroxyquinoline glycoconjugates and preliminary assay of their β1,4-GalT inhibitory and anti-cancer properties

8-Hydroxyquinoline scaffold is a privileged structure used in designing a new active agents with therapeutic potential. Its connections with the sugar unit is formed to improve the pharmacokinetic properties. The broad spectrum of activity of quinoline derivatives, especially glycoconjugates, is often associated with the ability to chelate metal ions or with the ability to intercalate into DNA. Simple and effective methods of synthesis glycoconjugates of 8-hydroxyquinoline and 8-hydroxyquinaldine derivatives, containing an O-glycosidic bond or a 1,2,3-triazole linker in their structure, have been developed. The obtained glycoconjugates were tested for their ability to inhibit β-1,4-Galactosyltransferase, as well as inhibit cancer cell proliferation. It was found that used glycoconjugation strategy influenced both improvement of activity and improvement of the bioavailability of 8-HQ derivatives. Their activity depends on type of attached sugar, presence of protecting groups in sugar moiety and presence of a linker between sugar and quinolone aglycone.     

Synthesis and Antitumor Activity of 2-Alkanesulfinyl (or Alkanesulfonyl)-7-methyl-5H-1,3,4-thiadiazolo[3,2-a]pyrimidin-5-ones

The repressing effect on the propagation of cultured Ehrlich ascites tumor cells by 1, 3, 4-thiadiazolo [3, 2-a] pyrimidine and s-triazolo [1, 5-a] pyrimidine derivatives was examined. Then the relationship between structure and activity as to a series of active compounds was discussed.

The results showed that substituent groups on the 2-position of 1, 3, 4-thiadiazolo [3, 2-a]-pyrimidine took an important part to reveal the cytotoxic activity. Especially, the strong activity was found among the compounds which had electrophilic substituents such as alkylsulfoxide, alkylsulfone at the 2-position.     

精氨酸对艾氏腹水癌细胞体外作用的机制探讨

本研究采用小鼠艾氏腹水癌细胞探讨了精氨酸对一些肿瘤细胞体外作用的可能机制。结果表明精氨酸对艾氏腹水癌细胞体外蛋白质合成有显著的抑制作用,其作用受培养介质中一些氨基酸的影响;细胞内游离氨基酸浓度分析结果提示精氨酸的作用可能并不是通过干扰细胞内游离氨基酸池所引起,其具体作用机制尚待进一步实验的揭示。     

The effect of the fluorescent probe, 3,3′-dipropylthiodicarbocyanine iodide,on the membrane potential of Ehrlich ascites tumor cells

The effects of the potential-sensitive fluorescent dye, 3,3′dipropylthiodicarbocyanine iodide, on factors establishing the membrane potential of Ehrlich ascites tumor cells have been tested. The dye itself induces membrane hyperpolarization as monitored by electrophysiological methods. In addition, the dye inhibits active (Na⁺+K⁺-transport and increases cell membrane permeability to K⁺ by about 65% in these cells.     

A permeability change in Ehrlich ascites tumor cells caused by dextran sulfate and its repair by ascites fluid or Ca2+ ions

Exposure of Ehrlich ascites tumor cells to the polyanion dextran sulfate impaired the active transport of α-aminoisobutyric acid and made the cells nonspecifically permeable to sorbitol and erythrosin B. Subsequent incubation with ascites fluid from tumor-bearing mice restored active transport and repaired the permeability barrier in dextran sulfate-treated cells. Ascites fluid was ineffective after dialysis or the addition of ethylene glycol bis(β-aminoethyl ether)-N,N′-tetraacetic acid, suggesting the involvement of Ca²⁺ ions in repair. Treatment with CaCl₂ and glucose under specific conditions restored the transport activity of dextran sulfate-treated cells about three-fourths as effectively as was the case for ascites fluid. This procedure, which involves chemically characterized materials, may be advantageous when one wishes to incorporate impermeable substances into the cells.     

Synthesis,characterization and antitumour properties of some metal(II) complexes of 2-pyridinecarboxaldehyde 2′-pyridylhydrazone and related compounds

Metal complexes of 2-pyridinecarboxaldehyde 2′-pyridylhydrazone (PCPH) and related compounds with manganese(II), iron(II), cobalt(II), nickel(Il), copper(II), zinc(II) and platinum(II) were synthesized and characterized by magnetic susceptibility measurements down to liquid nitrogen temperature and also by electronic, infrared, electron spin resonance and Mössbauer spectra. All the metal(II) complexes appeared to be monomeric, high-spin, five-coordinate (square-pyramidal) (X = Cl⁻ or OAc⁻), except for Ni(PCPH)Cl₂ which is polymeric, high-spin, six-coordinate. Each ligand behaved as a tridentate NNN donor, via the pyridine nitrogen, azomethine nitrogen, and pyridine or quinoline nitrogen. One of the most active agents of this series, Cu(PCPH)Cl₂, showed antitumour activity against a variety of transplanted tumours, including Sarcoma 180, Ehrlich carcinoma and L1210 leukaemia sensitive to α(N)-heterocyclic carboxaldehyde thiosemicarbazones. This agent caused inhibition of ³H-thymidine and ³H-uridine incorporation into DNA and RNA, respectively, of Sarcoma 180 ascites cells; protein biosynthesis was relatively insensitive to the action of this agent.     

THE ISOLATION OF LYSOSOMES FROM EHRLICH ASCITES TUMOR CELLS FOLLOWING PRETREATMENT OF MICE WITH TRITON WR-1339

A method is described for obtaining highly purified lysosomes from Ehrlich ascites tumo cells grown in mice injected with Triton WR-1339. The isolated particles show a high specific activity for aryl sulfatase, representing an 80–90-fold purification over the homogenate, and a 15–18% yield of the total enzyme activity. Mitochondrial and microsomal marker enzymes are present in negligible amounts (0.2% of the activity of the homogenate). The biochemical evidence for a rather high degree of homogeneity of the fraction is supported by the electron microscopic examination of the purified lysosomes. The intracellular localizations of N-acetyl-β-glucosaminidase, NADH-cytochrome c reductase and NADPH-cytochrome c reductase in Ehrlich ascites cells are also reported, the first two being present in highest concentration in the combined mitochondrial-lysosomal fraction and the third in the microsomal fraction.     

Absence of anthracycline-induced degradation of nuclear DNA in Ehrlich ascites tumour cells

The in vivo effects of anthracycline antibiotics on the integrity of Ehrlich ascites tumour cell DNA have been studied by sedimentation analysis of nuclear structures containing superhelical DNA in neutral sucrose gradients. These fast-sedimenting protein-DNA complexes may be released by gently lysing cells in solution containing non-ionic detergents and high NaCl concentrations (1.95 M). The supercoiled structure of DNA in these protein-DNA complexes is suggested by the characteristic sedimentation in the presence of intercalating agents. Apparently, no DNA damage could be detected in Ehrlich cells from 7-day-old tumours within 3 h after various doses of daunomycin (0.5–10 mg/kg of body wt.) were administered i.p. to mice. Sedimentation anomalies could not be observed even 15 or 30 h after administration of therapeutic doses of daunomycin or adriamycin. In contrast, at 30 min after administration to mice, therapeutic doses of bleomycin (2–8 mg/kg) caused extensive fragmentation of tumour cell DNA, which could be monitored as slowly sedimenting DNA structures (compared with the control). Similarly, DNA damage could be induced by procarbazine at therapeutic doses. Exposure to bleomycin or procarbazine abolished the characteristic biphasic response to ethidium bromide. The absence of anthra-cycline-induced degradation of Ehrlich ascites tumour cell DNA is apparently in contrast with the DNA damage observed in L1210 tumour cells. These observations suggest that DNA damage is not a necessary condition for antitumour activity.     

Heterogeneity of alkaline ribonuclease in the mouse and Ehrlich ascites cells.

The specific activity of alkaline RNase II was l00 to 1800 times higher in mouse pancreas than in mouse liver, serum, ascites fluid, and Ehrlich ascites cell grown intraperitoneally. Ehrlich ascites cells grown in cell culture medium had a much lower alkaline RNase II activity than cells grown intraperitoneally. Chromatography on CM-52 cellulose of acid- and heat-treated preparations showned a considerable heterogeneity of the mouse enzymes. Depending on the source of the extract, two to six forms fo alkaline RNase were eluted. Pancreatic extract contained two RNase forms. These also seemed to be present as minor components in preparations from other sources except Ehrlich ascites cells grown in vitro. Ehrlich ascites cells grown in vivo contained forms of the RNase which were not present in other extracts. Possible reasons for this heterogeneity were investigated. In addition to their stability to acid and heat the different RNase forms were similar in that they were much more active at alkaline pH than at acidic pH, they did not require divalent metal ions for activity, and they degraded RNA 'endonucleolytically.' Also, native DNA, denatured DNA, and poly A were poor substrates compared with RNA. Some differences seemed to exist, however, with respect to their abilities to degrade poly U and poly C and their sensitivities to the endogenous RNase inhibitor.     

N-[(Dihydroxyphenyl)acyl]serotonins as potent inhibitors of tyrosinase from mouse and human melanoma cells

A series of N-acyl derivatives of tyramine, tryptamine, and serotonin were synthesized and tested on anti-melanogenic activity. The serotonin derivatives such as N-caffeoylserotonin (3) and N-protocatechuoylserotonin (9) were inhibitory to tyrosinase from mouse B16 and human HMV-II melanoma cells, while the corresponding derivatives of tryptamine and 5-methoxytryptamine were almost inactive or less active than the serotonin derivatives. The inhibitory activity of the serotonin derivatives increased with increasing number of phenolic hydroxyl groups in the acyl moiety. Melanin formation in the culture of B16 cells was suppressed by 3 and 9 with no cytotoxicity in the concentration range tested (IC₅₀ = 15, 3 and 111 μM for 3, 9, and kojic acid, respectively). Thus the N-acylserotonin derivatives having a dihydroxyphenyl group are potential anti-melanogenic agents. Their inhibition of tyrosinase is primarily performed through the 5-hydroxyindole moiety and further strengthened by the phenolic hydroxyl groups in the acyl moiety.     

Heavy metals and spermatozoan motility. II. Turbidity changes induced by divalent cations and adenosinetriphosphate in sea urchin sperm flagella

The initial binding of synthetic polyribonucleotides and different RNAs to Ehrlich ascites cells has been studied using cell electrophoresis. When cells were pre-incubated in the presence of polylysine significant differences in the binding of different polyribonucleotides were observed. For example, Poly (A):Poly (U) caused a greater change in electrophoretic mobility than Poly (I):Poly (C). The increased electrophoretically detectable change after treatment with Ehrlich ascites RNA compared with E. coli tRNA could be correlated with increased uptakes of labelled Ehrlich ascites RNA compared with tRNA. An interesting observation was that when Poly (A) was added before Poly (U), a greater effect on electrophoretic mobility was found compared with the effects when the order of addition was reversed. It is suggested that copolymer formation from the homopolymers can occur at the cell surface.     

ESR studies of molecular interactions of copper(II) nirvanol and copper(II) diisopropylsalicylate with Ehrlich ascites tumor cells

ESR spectra have been obtained after addition of either a cupric phenylhydantoin or a cupric diisopropylsalicylate complex to Ehrlich ascites tumor cells. It is shown that some of the complex remains in the cupric state. Because the ESR parameters of these complexes in the presence of cells differ from the ESR parameters for these complexes in the absence of cells, in the presence of cells either adducts or new cupric complexes are formed. The fast motion of these complexes, as determined from room temperature ESR spectra, is characteristic of complexes with molecular weights less than 1500.     

Ion transport by ouabain resistant and sensitive ehrlich ascites carcinoma cells

Cell division, net Na⁺-K⁺ and amino-acid transport of cultured Ehrlich ascites is reversibly inhibited by Ouabain at a final concentration of 1 × 10^–3M. A line of Ehrlich ascites cells resistant to the growth inhibiting effects of Ouabain has been developed. These cells behave similarly to Ouabain-sensitive cells in the following respects doubling time, S phase time, chromosome number, cell surface charge density, rate of incorporation of C¹⁴ Uridine and ³H-Thymidine, sensitivity to Digoxin and Digitoxin, steady state Na⁺, K⁺ levels and rate of loss of K⁺ and gain of Na⁺ in cold. Ouabain resistant cells differ from sensitive cells only with respect to the effect of ouabain on active Na⁺, K⁺ transport. Although Ouabain inhibits active Na⁺, K⁺ transport in sensitive cells it has no significant effect in resistant cells.