Synergistic cytotoxic effect of human recombinant tumor necrosis factor alpha combined with dihydroambazone.

Dihydroambazone (DHA) is a water-soluble derivative of the experimental anticancer drug ambazone. In vitro, a combination of DHA and human recombinant tumor necrosis factor alpha (TNF) exerted a strong synergism of cytotoxicity against both mouse melanoma B16K cells and the TNF-sensitive mouse fibroblast line L-M (S). Furthermore, in a colony-forming assay with B16K cells a combination of TNF and DHA inhibited colony-formation much more severely than either drug alone. An increased antiproliferative efficiency was also confirmed in vivo against established subcutaneous melanoma B16 tumors of C57BL/6 mice.

Physiochemical characterization of substituted chromeno[4,3-b][1,5]benzodiazepine stereoisomers designed as cell membrane active antitumor agents.

As an alternative to naturally occurring pyrrolo[2,1-c][1,4]benzodiazepines (e.g., antramycin) which possess properties of DNA alkylation, we have designed several antileukemic chromeno[4,3-b][1,5]benzodiazepine derivatives with potential activity toward leukemia cell membranes and the cyclic nucleotide system. The cis and trans diastereoisomers were characterized by NMR. The absolute configurations of the enantiomers were established by X-ray diffraction and circular dichroism (CD) measurements. By means of absorption spectroscopy and determinations of fluorescence and fluorescence decay, it was found that the cancerostatically active compound (+)(6aR, 13aS)-3,4-dimethoxy-10,11-dimethyl-6,6a,7,8,13, 13a-hexahydrochromeno[4,3-b][1,5]benzodiazepine (ZIMET 54/79) and its biologically inactive (-) enantiomer (ZIMET 55/79) interact with liposomal membranes. At pH values of 6.0 and 7.3 the long-wave absorption bands of these agents showed weak bathochromic and hypochromic effects upon addition of neutral, and positively and negatively charged phosphatidylcholine and phosphatidylcholine/cholesterol liposomes. Such spectral changes are interpreted as resulting from the binding of both agents to phospholipid bilayers. Steady-state determinations using the membrane probe 1-anilino-8-naphthalenesulfonic acid (1,8-ANS) led to the observation of a small decrease in fluorescence intensity in the presence of either agent. Time-resolved measurements demonstrate that the mechanism of action of the agents occurs mainly through the partial displacement of probe molecules from regions of hydrophobic binding to areas of greater solvent accessibility. No significant differences in binding between the cancerostatically active and inactive enantiomers with liposomes (archiral systems) were detectable on the basis of spectrophotometric and fluorescence determinations. Cell membrane bound adenylate cyclase is stimulated by ZIMET 54/79, resulting in an increase of 103% in the level of cAMP in mouse L1210 leukemia cells. On examination of structure-activity relationships, it was found that the biological activity (leukemia L1210, P388, Lewis lung carcinoma, melanoma B16, increase in cAMP) is correlated with the particular configuration (6aR,13aS) and type of substituent at positions 3 and 4 of the benzo ring in the case of alkoxy groups and positions 10 and 11 for methyl groups. No activity was detected toward DNA/RNA using microbial test systems.

Griseorubins, a new family of antibiotics with antimicrobial and antitumor activity. II. Biological properties and antitumor activity of the antibiotic complex griseorubin.

The antibiotic complex griseorubin has antimicrobial activity against Gram-positive as well as -negative bacteria, mycobacteria, mycoplasma and protozoa in vitro but it is not active against yeast and fungi. Tests with transplantable rodent tumors indicate that griseorubin is inhibitory to the growth of lymphatic leukemia L1210 in mice and Zajdela ascites hepatoma in rats. The acute LD50 of griseorubin in mice is 50 mg/kg of body weight when given intraperitoneally. Attempts to potentiate the antitumor activity by complexing with DNA proved to be unsuccessful.

Aurantimycins, new depsipeptide antibiotics from Streptomyces aurantiacus IMET 43917. Production, isolation, structure elucidation, and biological activity.

Aurantimycins A (1), B (2) and C (3) were isolated from the mycelium of Streptomyces aurantiacus JA 4570 as new representatives of the azinothricin group of hexadepsipeptide antibiotics. Their structures were settled by X-ray diffraction analysis of crystalline aurantimycin A (1), high field homo- and heteronuclear 2D NMR experiments, high-resolution mass spectrometry and amino acid analysis. Aurantimycins are characterized by a new side chain containing fourteen carbon atoms. They display strong activity against Gram-positive bacteria and cytotoxic effects against L-929 mouse fibroblast cells.

Helioferins; novel antifungal lipopeptides from Mycogone rosea: screening, isolation, structures and biological properties.

Helioferins A and B were detected as novel aminolipopeptides in cultures of Mycogone rosea DSM 8822 in the course of a screening for mediators of helianthate anion transfer from aqueous to toluene phases. Their structures as novel antibiotics and cytotoxic agents were elucidated by mass spectrometry and NMR spectroscopic methods. Antimicrobial activity was estimated against Candida albicans and Gram-positive bacteria including Mycobacterium spp.

Preselection of Potential Cancerostatics by Automatic Analysis of Suspended and Adherent Cells Incubated in Microplates.

Alternative toxicological screening programmes, without the use of animal experiments, are intended to eliminate dangerous substances and to find new pharmacologically active agents in cell cultures. They can also provide information on the cytostatic activities of the agents. Intercalating cytostatics which bind DNA were selected by measuring the statistical distributions of the cell diameters of K-562 and L-929 cells by using an electronic cell analyser (CASY1). These compounds were identified by cell enlargement or from flat concentration-activity curves created with the cell analyser system. Incubation for 72 hours with DNA-binding agents, such as doxorubicin, daunorubicin and Mitoxantron®, resulted in enlargement of cell diameter and cell volume. The antineoplastic agents actinomycin D and ambazone had no comparable effect. Comparisons of the different parameters obtained with CASY1 measurement were performed with Microsoft EXCEL.

[Antineoplastic activity and toxicity of dihydroambazone in comparison with ambazone (1,4-benzoquinone-guanylhydrazone-thiosemicarbazone)]. / Antineoplastische Wirksamkeit und Toxizität von Dihydroambazon im Vergleich zu Ambazon (1,4-Benzochinon-guanylhydrazon-thiosemicarbazon).

Dihydroambazone 1, a soluble derivative of ambazone, was tested with an admixture of ascorbic acid (0.1, 0.25, or 0.5% in distilled water) for antineoplastic activity by different routes (i.p., p.o., s.c., i.v.) against leukemia P388, and by s.c. application against Lewis lung carcinoma on B6D2F1-mice. The results were compared with that of ambazone. 1 was as active as ambazone upon the per os d 1-4 schedule only. Ascorbic acid, added for stabilization of 1, had no significant influence on the results. Intravenously given 1 was of low activity. It proved to be toxic at 100 mg/kg body mass. The i.v. toxicity was estimated approximately on B6D2F1-mice (LD50: 150 mg/kg; LD100: 175 mg/kg; maximum tolerated dose (MTD): 100 mg/kg. A comparison between the MTD's of 1 and ambazone in mice and rats (Wistar) showed partly a somewhat better p.o. compatibility of 1. The expectation of a favourable i.v. applicable derivative from the otherwise in water nearly insoluble ambazone could not be realized.

[Antineoplastic and curative antileukemic activity of 1,4-benzoquinone guanylhydrazone thiosemicarbazone and its hydrochloride on in vivo murine models]. / Tumorhemmende und kurative antileukämische Wirksamkeit von 1,4-Benzochinonguanylhydrazonthiosemicarbazon und dessen Hydrochlorid an murinen Testmodellen in vivo.

By means of four murine models, the authors demonstrated in vivo that 1,4-benzoquinone guanylhydrazone thiosemicarbazone (1), which is known to be antimicrobially active, and its hydrochloride (2) exert an antineoplastic effect. In leukaemia P 388 and leukaemia L 1210 both compounds had a curative action already after four oral administrations. The "cured" animals were resistant or cross-resistant to further transmissions of leukaemia. The resistance was transmissible by splenocytes.

[N-quaternary derivatives of tilorone]. / N-quartäre Derivate des Tilorons.

Tilorone (free base) reacts with alkyl halides forming quaternary ammonium salts. Bis- as well as mono quaternary compounds (2 resp. 3) were synthesized. The tilorone-bis-methoiodide (2a) was converted to several carbonyl derivatives (4 and 5). All produced compounds did not show any cytostatic activity against the murine leukemias L 1210 and P 388 in vivo. Especially the bis-quaternary derivatives 2 were highly toxic in the mouse.

[Carbonyl derivatives of tilorone. Part 2: On the cancerostatic activity of carbonyl derivatives of tilorone (author's transl)]. / Carbonylderivate des Tilorons. 2. Mitteilung: Zur cancerostatischen Wirksamkeit von Carbonylderivaten des Tilorons.

A series of carbonyl derivatives of tilorone was synthetized by reaction with appropriate amino compounds, mainly hydrazines and hydrazides. The condensation products obtained were tested for cancerostatic activity against the murine leucaemia L 1210 and the Walker carcinosarcoma of the rat. Only three of the substances under investigation (1a, 5, 13) proved active against the Walker carcinosarcoma, one of which (5) being comparable to tilorone. No activity against L 1210 was observed, even tilorone exerted no effect. The reduction in activity against the Walker carcinosarcoma which resulted from the carbonyl substitution might be caused by a decrease in the ability to intercalate into DNA.

[Synthesis and biological activity of 1,4-benzoquinone-guanylhydrazone-thiosemicarbazone analogs. 1. Substitution at the S atom]. / Zur Synthese und biologischen Wirksamkeit von Analogen des 1,4-Benzochinon-guanylhydrazon-thiosemicarbazons. 1. Mitteilung: Substitution am S-Atom.

The synthesis of S-substituted derivatives of 1,4-benzoquinone-guanylhydrazone-thiosemicarbazone is described. The obtained 1,4-benzoquinone-guanylhydrazone-S-alkyl (resp. aralkyl)-isothiosemicarbazones, in comparison with the unsubstituted standard compound, showed a significantly decreased biological activity against the murine leukemias L 1210 and P 388 as well as against the growth of several kinds of bacteria. Therefore the S-substitution seems not to be useful for reaching a maximum activity.

[Anthracycline antibiotics from genetically modified streptomycetes. The isolation, spectroscopic structural elucidation and biologic effects of beta-rhodomycin I]. / Anthracyclinantibiotica genetisch modifizierter Streptomyceten. Zur Isolierung, spektroskopischen Strukturaufklärung und biologischen Wirkung von beta-Rhodomycin-1.

By mutagenic treatment and selection procedures the mutant ZIMET 43678 was obtained from a population of the interspecific recombinant Streptomyces violaceus subsp. iremyceticus ZIMET 43615, which showed a changed spectrum of secondary metabolites. The main component isolated from the fermentation broth was a pure anthracycline evidenced by TLC. By means of acid hydrolysis, identification of the degradation products and also by spectroscopic UV/VIS-, IR-, MS-, 1H/13C-NMR- and CD-investigations with intact anthracycline the structure 7-(alpha-L- rhodosaminyl )-beta- rhodomycinon with the absolute configuration 7S, 9R , 10R was found. The anthracycline called beta- rhodomycin -1 (1) exhibits antimicrobial and cytostatic activity in vitro and is also effective on tumour cells in tumour bearing animals.

[Cancerostatically active 6,6a,7,8,13,13a-hexahydro-1-benzopyrano[4,3-b]-1,5-benzodiazepine diastereoisomers (author's transl)]. / Cancerostatisch wirksame 6,6a,7,8,13,13a-Hexahydro-1-benzopyrano[4,3-b]-1,5-benzodiazepin-Diastereoisomere.

The action of many psychotropic drugs on the adenylate cyclase system and its role in the regulation of tumour cell division justify the expectance that potentially psychotropic 1-benzopyrano[4,3-b]-1,5-benzodiazepine derivatives (3a,b and 6a,b) will also exert a cancerostatic effect. The synthesis of 6,6a,7,8,13,13a-hexahydro-1-benzopyrano[4,3-b]-1,5-benzodiazepines (4a and b) and their separation into the antileukaemic (L 1210) cis-forms and the inefficacious trans-forms are described. The cis-form 5a, unlike the trans-form 6a, stimulated the adenylate cyclase system.

Influence of 1,4-benzoquinone derivatives and azomethines on microtubule formation in vitro and experimental leukemias.

Using two groups of substances (derivatives of 1,4-benzoquinone and azomethines) it was compared their effect on the microtubule formation in vitro and on experimental leukemias. 9 from the 28 substances tested acted cancerostatically, 4 substances inhibited microtubule assembly. 3 compounds (fluorenoneazomethines) revealed both effects.

[The synthesis and biologic activity of analogs of 1,4-benzoquinone-guanylhydrazone-thiosemicarbazone. 2. Substitution at the quinone ring by alkyl groups]. / Zur Synthese und biologischen Wirksamkeit von Analogen des 1,4-Benzochinon-guanylhydrazon-thiosemicarbazons. 2. Mitteilung: Substitution am Chinonring durch Alkylreste.

Because of the anticancer activity of 1,4-benzoquinone-guanylhydrazone-thiosemicarbazone (1a) some analogues were synthesized, containing alkyl groups at the quinone moiety. If necessary, the structure of the obtained compounds was confirmed by 1H-NMR-spectroscopy. The anticancer and the antibacterial activities were investigated. The guanylhydrazone-thiosemicarbazones of tolu-,p-xylo-and thymo-quinone showed much lower activities not only against the murine leukemias L 1210 and P 388, but also against Bacillus subtilis ATCC 6633. No correlation could be found between the biological activity and the redox potential.