Relationship of hypolipidemic and antineoplastic activities of tricyclohexyl- and triphenylphosphine boranes, carboxyboranes, cyanoboranes, and related derivatives.

A series of tricyclohexyl- and triphenylphosphine boranes, carboxyboranes and cyanoboranes were synthesized. These compounds have potent hypolipidemic effects, antineoplastic and antiinflammatory activities in rodents. Furthermore, they demonstrated potent cyctotoxicity against standard human tissue culture lines. The compounds which afforded the best hypolipidemic activity, i.e. greater than 40% reduction of serum cholesterol and triglyceride levels, were diphenyl-(4-methylphenyl)-phosphine borane and triphenylphosphine carboxyborane. Other derivatives demonstrated more potent antineoplastic activity against the Ehrlich ascites carcinoma growth including triphenylphosphine cyanoborane, 2-amino-4-methyl-pyridine cyanoborane and 2-amino-pyridine cyanoborane. Most of the derivatives showed good activity against murine L1210 lymphoid leukemia, Tmolt3 human leukemia, uterine HeLaS cells, and human glioma cell growth. Select compounds were active against colon adenocarcinoma, KB nasopharynx, lung bronchogenic and osteosarcoma cell growth. Tricyclohexyl- and triphenylphosphine boranes and the carboxy derivatives of the latter borane demonstrated good antiinflammatory activity.     

Antineoplastic agents. 1. N-Protected vinyl, 1,2-dihaloethyl, and cyanomethyl esters of phenylalanine

A series of N-protected vinyl, 1,2-dihaloethyl, and cyanomethyl esters of phenylalanine was synthesized and these compounds were evaluated for antitumor activity against the growth of Ehrlich ascites carcinoma in CF1 male mice (33 mg/kg/day), Walker 256 carcinosarcoma in Sprague-Dawley male rats (2.5 mg/kg/day), and P388 lymphocytic leukemia in DBA/2 mice (20 mg/kg/day). Structure-activity relationships were evaluated and acute toxicity studies (LD50 determinations) in male CF1 mice were also carried out on selected compounds. Carbobenzoxy-L0phenylalanine vinyl ester (5), N-carbobenzoxy-L-phenylalanine 1,2-dibromoethyl ester (12), and N-carbobenzoxy-L-phenylalanine cyanomethyl ester (8) were found to be very potent inhibitors of Ehrlich ascites tumor growth at nontoxic doses cited above. Compounds 5 and 12 also tripled survival time in the Walker 256 system. LD50 values for compounds 5, 12, and 8 were greater than 2000 mg/kg (greater than 6.15 mmol/kg), 74 mg/kg (0.15 mmol/kg), and 150 mg/kg (0.44 mmol/kg), respectively.     

Synthesis, cytotoxicity, hypolipidemic and anti-inflammatory activities of amine-boranes and esters of boron analogues of choline and thiocholine.

Boron analogues of carbamoylcholine and thiocholine and esters of these analogues were prepared. These compounds were fairly stable toward hydrolysis and demonstrated moderate anti-inflammatory and hypolipidemic activities in mice. The hypolipidemic activity of the compounds at a dose of 8 mg/kg/day was equivalent in reducing lipid levels in serum to those of clofibrate at 150 mg/kg/day and lovastatin at 8 mg/kg/day. The compounds demonstrated significant cytotoxic activity against the growth of murine and human tumor cells; all were active against the growth of human HeLa-S3 uterine suspended cells, and some were active against murine L1210 lymphoid leukemia, human Tmolt3 leukemia cells, colorectal adenocarcinoma, KB nasopharynx, osteosarcoma, and glioma. These studies demonstrated that antimetabolite analogues of acetylcholine exhibit the same types of pharmacological activity as other boron-substituted betaine and amino acids. Furthermore, a strong positive correlation exists between hypolipidemic activity and cytotoxicity for these new choline derivatives, as has previously been demonstrated for other boron-containing amino acids, amides, esters, and peptides.     

Antineoplastic activity of a series of boron analogues of alpha-amino acids

A series of amine cyanoboranes, amine carboxyboranes, and boron analogues of alpha-amino acids have been investigated for antineoplastic activity against the growth of Ehrlich ascites cells. Additional studies demonstrated that the boron analogues inhibited DNA and RNA synthesis at 300 microM. The suppression of DNA synthesis of Ehrlich ascites cells correlated with the reduction of DNA polymerase, 5-phosphoribosyl-1-pyrophosphate amidotransferase, and dihydrofolate reductase activities afforded by the boron compounds. These derivatives did not suppress protein synthesis, thymidylate synthetase, or thymidine monophosphate kinase activities as previously reported for some boron antineoplastic agents.     

The antineoplastic activity of trimethylamine carboxyboranes and related esters and amides in murine and human tumor cell lines

Trimethylamine carboxyboranes including their esters and amides were shown to have antineoplastic activity in vivo against Ehrlich ascites carcinoma growth. The derivatization to the ester or amide did not necessarily improve activity. Cytotoxicity of the derivatives was observed against the growth of murine and human tumor cells. Selectivity was demonstrated by the boron derivatives in the human solid tumor screens. Almost all the compounds demonstrated cytotoxicity against single-cell suspension growths, eg Tmolt3, L1210, HeLa-S3. Selection of two compounds to examine their mode of action in L1210 lymphoid leukemia cells showed that the agents perferentially inhibited DNA synthesis followed by protein and RNA synthesis. The d(TTP) pools were markedly reduced because of inhibition of nucleotide kinase activity. The agents also inhibited regulatory enzymes in the de novo purine pathway and afforded DNA strand scission. These effects by the agents were probably additive to bring about tumor cell death.     

Boron betaine analogs: antitumor activity and effects on Ehrlich ascites tumor cell metabolism.

Several newly synthesized boron betaine analogs had antitumor activity in Ehrlich ascites, Walker 256 ascites carcinosarcoma, and Lewis lung screens and marginal activity in the B-16 melanotic melanoma screen. In vivo testing demonstrated that trimethylamine-cyanoborane inhibied Ehrlich ascites cell DNA and protein syntheses as well as gene modulation by chromatin protein phosphorylation and methylation. Trimethylamine-cyanoborane increased cyclic-AMP levels. In vitro testing showed that nuclear DNA polymerase, thymidylate synthetase, S-adenosylmethyltransferase, nonhistone chromatin methylation, deoxyribonuclease, ribonuclease, and cathepsin were inhibited by the boron analogs. These compounds did not demonstrate high antitumor activity at the doses employed, but blockage of methyl transfer from S-adenosylmethionine was established as a feasible method for controlling cell proliferation.     

Dicaffeoyltartaric acid analogues inhibit human immunodeficiency virus type 1 (HIV-1) integrase and HIV-1 replication at nontoxic concentrations

The human immunodeficiency virus type 1 (HIV-1) is a major health problem worldwide. In this study, 17 analogues of L-chicoric acid, a potent inhibitor of HIV integrase, were studied. Of these analogues, five submicromolar inhibitors of integrase were discovered and 13 compounds with activity against integrase at less than 10 microM were identified. Six demonstrated greater than 10-fold selectivity for HIV replication over cellular toxicity. Ten analogues inhibited HIV replication at nontoxic concentrations. Alteration of the linkages between the two bis-catechol rings, including the use of amides, mixed amide esters, cholate, and alkyl bridges, was explored. Amides were as active as esters but were more toxic in tissue culture. Alkyl and cholate bridges were significantly less potent against HIV-1 integrase in vitro and were inactive against HIV-1 replication. Two amino acid derivates and one digalloylderivative of L-chicoric acid (L-CA) showed improved selectivity over L-CA against integration in cell culture. These data suggest that in addition to the bis-catechols and free carboxylic acid groups reported previously, polar linkages are important constituents for optimal activity against HIV-1 integrase and that new derivatives can be developed with increased specificity for integration over HIV entry in vivo.     

Isolation and identification of pharmacologically active amino acids in skin and their structure-activity relationship on the guinea-pig ileum

1. Aqueous extracts of stratum corneum were found to cause histamine-like contractions of the guinea-pig ileum which were not antagonized by mepyramine, atropine or bromolysergic acid diethylamide.2. The compounds responsible for this contraction were isolated by chromatography and shown to be common amino acids, particularly L-serine and L-alanine which occur in abundance in the stratum corneum.3. Amino acid analogues were assayed on the guinea-pig ileum against alanine as standard. With the exception of gamma-amino butyric acid and L-alanine benzyl ester all analogues which had appreciable activity gave dose-response curves parallel to L-alanine.4. The response to L-alanine benzyl ester was abolished by mepyramine and this analogue appears to be a partial agonist on the histamine receptor.5. The effects of substitution on the equipotent molar ratios of amino acid analogues indicate that all four chemical groups attached to the alpha-carbon of L-alanine interact with the receptor.6. Our results suggest that the guinea-pig ileum contains an L-alpha-amino acid receptor.     

Effect of several d-morphinans on ascites tumors in mice

Dextromethorphan and its analogues (DM 16, DM 34, DM 72, DM 75 and DM 96) were examined for their effect on Ehrlich ascites carcinoma or ascites sarcoma-180 in female mice of the ddY strain. The suspension of Ehrlich carcinoma cells or sarcoma-180 cells was prepared from mice at 10 days after i.p. inoculation of the cells, using Hanks' balanced salt solution, and the cell suspension was inoculated i.p. into mice (2 X 10(6) viable cells/mouse). The chemicals dissolved in physiological saline containing 5% HCO-60 were then injected i.p. into the mice once daily for 5 successive days (5-40 mg/kg/day). In addition, mice given the tumor cells were treated with the saline containing 5% HCO-60 alone for 5 days (untreated mice). In groups of mice bearing Ehrlich ascites carcinoma or ascites sarcoma-180, the mean survival time of mice treated with 20-40 mg/kg/day of DM 96 was more than twice that of the corresponding untreated mice. The mean survival time of mice treated with 20 mg/kg/day of DM 96 was also longer than that of mice treated with 40 mg/kg/day of the other chemicals, irrespective of the ascites tumors. Concerning these survival times, the LD50 (i.p.) of DM 96 in mice differed slightly from that of other chemicals (88 mg/kg and 77-106 mg/kg). These results indicate that DM 96 is more active than the other chemicals against the ascites tumors in mice.     

Synthesis, characterization, antibacterial and cytotoxicity studies on some mixed ligand Th(IV) complexes

Mixed ligand Th(IV) complexes of the type [M(Q)2LNO3.H2O] have been synthesized using 8-hydroxyquinoline (HQ) as a primary ligand and N- and/or O- donor amino acids (HL) such as L-alanine, L-phenylalanine, L-serine and L-tyrosine as secondary ligands. The metal complexes have been characterized on the basis of elemental analysis, electrical conductance, room temperature magnetic susceptibility measurements, spectral and thermal studies. The electrical conductance studies of the complexes in DMF at 10(-3) M concentration indicate their non-electrolytic nature. Room temperature magnetic susceptibility measurements revealed diamagnetic nature of the complexes. Electronic absorption spectra of the complexes show intra-ligand and charge transfer transitions, respectively. The thermal analysis data of the complexes indicate the presence of a coordinated water molecule. The tube dilution method has been used to study the antibacterial activity of the complexes against the pathogenic bacteria S. aureus and E. coli. The results have been compared against those of control tetracycline, which was screened simultaneously and indicate mild antibacterial activity of the complexes. The representative complex has been screened for cytotoxicity (IC50) studies against Ehrlich ascites cells and Daltons lymphoma ascites cells and shows low cytotoxic activity.     

The difference of drug sensitivity of tumor cells on N-ethyloxycarbonylaminomethyl-L-isoleucine (A-145 (author's transl)]

N-Ethyloxycarbonylaminomehyl-L-isoleucine (A-145), a novel antitumor amino acid derivative, is an anti-tumor agent effect in cases of Ehrlich ascites rather than against Sarcoma-180. The chemotherapeutic index of A-145 was 14.9 for Ehrlich ascites carcinoma and 4.2 for ascites Sarcoma-180. Experimental studies on ddy mice regarding the difference in susceptibility of these two tumor cell lines to A-145 gave the following results. In in vivo experiments, the uptake of 14C-A-145 by Ehrlich ascites carcinoma was greater than by Sarcoma-180, i. e. the uptake ratio of Ehrlich ascites carcinoma/Sarcoma-180 was 1.52 at 30 min and 2.7 at 24 hr after injection. In in vivo experiments, there was no remarkable difference between Ehrlich ascites carcinoma and Sarcoma 180 in the subcellular distribution of 14C-A-145, and the majority of the radioactivity taken up was distributed in nuclei and cytosol fractions. In in vitro experiments, the uptake of 14C-A-145 by both cell lines was found to be temperature sensitive, glucose dependent, and decreased on addition of KCN, 2, 4-dinitrophenol or iodoacetic acid. In in vitro experiments, competitive inhibition by L-isoleucine on 14C-A-145 uptake into tumor cells was observed in both cell lines, however, in vitro experiments, the inhibitory effect of A-145 on cell growth in cultured Sarcoma-180 was not reversed by L-isoleucine.     

Pharmacological study on kefir--a fermented milk product in Caucasus. I. On antitumor activity (1)]

The antitumor activity of kefir (YK-1), a fermented milk product in Caucasus, was investigated. YK-1 at oral doses of 100 or 500 mg/kg inhibited the proliferation of solid tumor of Ehrlich ascites carcinoma transplanted subcutaneously in mice. YK-1 did not show an inhibitory effect on the ear swelling induced contact dermatitis caused by picryl chloride (PC-CD). However, YK-1 inhibited the immunosuppression in Ehrlich carcinoma-bearing mice and with the frozen and dried ascites of the tumor-bearing mice containing immunosuppressive substances (EC-sup) in PC-CD-induced mice. And also, YK-1 activated the immunosuppressive activity of spleen cells of mouse treated with EC-sup. These results suggest that YK-1 may have antitumor activity against Ehrlich carcinoma and activate the immunosuppression with it.     

Inhibition of mammalian tumour thymidylate synthetase by 2'-deoxyuridine 5'-phosphate analogues

This paper presents improved synthetic methods for the modification of 2'-deoxyuridine-5'-monophosphate and its 5-fluoro derivative, using trimethylphosphate in aqueous medium at pH 10. These modifications include methylation of the pyrimidine ring N(3) and/or esterification of the phosphate group. The 5'-methyl ester of dUMP was neither a substrate nor an inhibitor of Ehrlich ascites carcinoma thymidylate synthetase. By contrast, the corresponding methyl ester of FdUMP was a tight-binding inhibitor of the enzyme from L1210, Ehrlich ascites carcinoma and CCRF-CEM cells. 3-Methyl-dUMP, fixed in the 4-keto form, exhibited only very weak substrate activity with the Ehrlich ascites carcinoma enzyme. The dUMP analogues 5-ethyl-dUMP and 5-propyl-dUMP were found to be competitive inhibitors of thymidylate synthetase from L1210, Ehrlich ascites carcinoma and HeLa cells, the former being the more potent inhibitor. Both analogues were shown to bind cooperatively to each of the mouse tumour enzymes. Two molecules of inhibitor interacted with a single enzyme molecule, reflected by the parabolic character of the replots of the slope versus inhibitor concentration. The parent dTMP was a stronger inhibitor of the mouse tumour enzymes than its higher alkyl homologues.     

Synthesis and evaluation of curcumin analogues as cytotoxic agents

Seventeen curcumin analogues were prepared and evaluated for in vitro and in vivo cytotoxicity against an Ehrlich ascites carcinoma (EAC). In vitro results revealed that compounds 10, 7, and 12 were the most potent analogues against EAC respectively. However, in vivo evaluation of compound 10 proved its capability to normalize the blood picture compared with 5-fluorouracil, a well-known anticancer drug.     

Synthesis and antitumor evaluation of selected 5,6-disubstituted 1(2)H-indazole-4,7-diones

A series of novel aziridinyl-substituted 1(2)H-indazole-4,7-diones and related 1(2)H-indazole-4,7-diones was synthesized and tested against Ehrlich ascites carcinoma growth in male CF1 mice. Ten of the test compounds, including two aziridinyl-substituted 1(2)H-indazole-4,7-diones, were found to be significantly active (inhibition of tumor growth greater than 80%) in the Ehrlich ascites carcinoma screen. Several structure-activity relationships were indicated for antitumor activity in this screen. An aziridinyl-substituted derivative, 5-aziridinyl-6-chloro-1H-indazole-4,7-dione (8a), also exhibited significant activity against the growth of P-388 lymphocytic leukemia cells in male BDF1 mice (% T/C = 145; % T/C greater than 125 is considered significant).     

Natural killer cell activity and anti-tumour effects of dehydrocrotonin and its synthetic derivatives

In this work, the anti-tumour properties of dehydrocrotonin and its derivatives were investigated in vitro and in vivo using the Ehrlich ascites tumour model. Treatment of Ehrlich ascites tumour-bearing mice with 20 mg/kg dehydrocrotonin for 4 days significantly increased survival, whereas administration of dehydrocrotonin derivatives was ineffective in affording protection. Compound IV exhibited little activity against Ehrlich tumour cells in vitro. Investigation of the effects of dehydrocrotonin treatment on total natural killer (NK) cell activity of tumour-bearing mice as a possible mechanism of dehydrocrotonin action in vivo revealed that this sesquiterpene lactone significantly improved NK cytotoxicity against YAC-1, a Moloney virus-induced mouse T-cell lymphoma of A/SN origin. As expected, tumour growth in non-treated mice markedly suppressed NK cell cytolysis. No effects on NK functional activity were observed in normal mice receiving dehydrocrotonin. In summary, only the natural compound exhibits anti-tumour efficacy and immunomodulatory actions in vivo, which may be related to its chemical structure.     

Antitumor agents. 16. Steroidal alpha-methylene-gamma-lactones.

Several novel steroidal alpha-methylene-gamma-lactones and related derivatives have been synthesized as potential steroid alkylating antitumor agents. The synthesis of these compounds involved the convenient Reformatsky-type reaction between ethyl-alpha-(bromomethyl)acrylate and the proper steroidal ketones. In vitro assay for the cytotoxicity of these compounds against the growth of tissue culture cells originating from human epidermoid carcinoma of the larynx (H.Ep.-2) has shown significant activity. Cytotoxicity was improved at least sixfold with the introduction of lipophilic steroidal character. Preliminary in vivo tumor assay also indicated that these compounds were active against Walker 256 carcinosarcoma in rats and were inactive against both L1210 lymphoid leukemia and Ehrlich ascites carcinoma in mice. However, the simple alpha-methylene-beta,beta-dicarbethoxy-gamma-butyrolactone significantly inhibited Ehrlich ascites tumor growth.     

Antitumor organometallics. II. Inhibitory effects of two diphenyl-antimony (III) dithiophosphorus derivatives on in vitro and in vivo Ehrlich ascites tumor.

(Diphenylphosphinodithioato) diphenylantimony (III), Ph2SbS2PPh2 (1) and (diisopropylphosphorodithioato) diphenylantimony(III), Ph2SbS2P(OPri)2 (2) were tested in vivo in male AKR mice and in vitro against Ehrlich ascites tumor cells. Both compounds exhibited dose-dependent inhibitory effects on in vivo tumor growth and on in vitro cell proliferation, cell viability, respiration and protein synthesis. The activities of some enzymes involved in energetic metabolism (Ca-ATPase, LDH, G6Pase) were exacerbated in vitro. The inhibitory effects could be related to the imbalance between ATP-producing and ATP-consuming processes in Ehrlich ascites tumor cells and also to their cell-cycle specificities.     

Antitumour metallocenes: structure-activity studies and interactions with biomolecules

The metallocene dihalides are a relatively new class of small, hydrophobic organometallic anticancer agents that exhibit antitumour properties against numerous cell lines including leukemias P388 and L1210, colon 38 and Lewis lung carcinomas, B16 melanoma, solid and fluid Ehrlich ascites tumours and several human colon and lung carcinomas transplanted into athymic mice. Titanocene dichloride 1 has been the most widely studied metallocene and the drug is currently in phase II clinical trials. Formation of metallocene-DNA complexes has been implicated in the mechanism of antitumour properties of the metallocenes, as both titanocene dichloride 1 and vanadocene dichloride 2 inhibit DNA and RNA synthesis, and titanium and vanadium accumulate in nucleic acid-rich regions of tumour cells. However, in contrast to the well characterized platinum-based anticancer drugs, the active species responsible for antitumour activity in vivo has not been identified and the mechanism whereby irreparable DNA damage and/or structural modification of DNA or other cellular targets occurs is poorly understood. This review will focus on recent studies that have been carried out in order to identify the biologically active species and more fully understand the molecular level mechanism of action of the metallocene dihalides. Studies with nucleotides, oligonucleotides, DNA and proteins including topoisomerases, protein kinase C and transferrin have provided important insight into potential cellular transport mechanisms and the interaction of metallocenes with biomolecular targets. New structure activity studies including the design of hydrolytically stable metallocenes and the preparation of highly water soluble amino acid analogues have not led to improved anticancer activity of titanocene dichloride 1. The vastly different chemical and hydrolytic stability of each of the metallocenes points to a unique mechanism of action of each metallocene in vivo.