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In the search for new anticancer drugs. XV. Various aliphatic and aromatic hydrazones containing the N,N;N',N'-bis(1,2-ethanediyl)phosphoric diamide moiety.

The scope of the structure-anticancer activity relationship among various aliphatic and aromatic hydrazones containing the N,N,N',N'-bis(1,2-ethanediyl)-phosphoric diamide moiety was studied. A total of 19 compounds were tested in vivo, using murine lymphocytic leukemia P388. At optimum dose all these compounds were active. The highest activity was exhibited by the N,N;N',N'-bis(1,2-ethanediyl)-[N2-(p-chlorobenzylidene)-N1- hydrazin-1-yl]phosphoric triamide, N,N;N',N'-bis(1,2-ethanediyl)-N2-(p-chlorobenzylidene)-N1- methylhydrazin-1-yl]phosphoric triamide and N,N;N',N'-bis(1,2-ethanediyl)-[N2-(p-chlorobenzylidene)-N1- phenylhydrazin-1-yl]phosphoric triamide as is evidenced by the percent T/C of 212, 194 and 192, respectively. An attempt was made to correlate the anticancer activities with the corresponding lipophilicities. On the basis of the activity-lipophilicity results, it is concluded that, in general, the activity scale follows the lipophilicity scale in the reverse order, i.e. the more active compounds possess lower lipophilicity than the less active compounds.

Animals↗

In the search for new anticancer drugs. XVIII. Various mono- and bis-anthraquinone hydrazones containing the N,N;N',N'-bis(1,2-ethanediyl)phosphoric diamide moiety.

The structure-anticancer activity and the activity-lipophilicity relationship of 8 mono- and bis-anthraquinone hydrazones containing the N,N;N',N'-bis(1,2-ethanediyl) phosphoric diamide moiety were evaluated. These compounds were tested in vivo, using murine lymphocytic leukemia P388. Seven of these compounds were active and one was marginal at optimum doses. The highest activity was exhibited by the bis[N,N;N',N'-bis(1,2-ethanediyl)-[N2-(1',4',5',8'-tetrahydroxy anthracenylidene)-N1-methyl hydrazin-1-yl]]-phosphoric triamide, bis[N,N;N',N'-bis(1,2-ethanediyl)-[N2-(1',4'-dihydroxy anthracenylidene)-N1-methylhydrazin-1-yl]]phosphoric triamide and bis-[N,N;N',N'-bis(1,2-ethanediyl)-[N2-(1',4',5',8'-tetrahydroxy anthracenylidene)-N1-phenylhydrazin-1-yl]]phosphoric triamide as is evidenced by their percent T/C of 183, 175 and 172, respectively. The correlation of the anticancer activities of these compounds with their lipophilicities leads to the general hypothesis that the intercalating and alkylating capabilities of a potential drug may play only a secondary role as compared to the selective permeability of the drug through normal and cancerous membranes.

Alkylating Agents↗

Effect of anticancer drugs and hyperthermia on nasopharyngeal carcinoma cell line in vitro.

The therapeutic effects of 10 anticancer drugs on a cultured nasopharyngeal carcinoma (NPC) cell line were examined by tritiated thymidine incorporation-inhibition assay and growth inhibition assay by a microphotometric method. The NPC cell line was found to be heterogeneous in terms of sensitivity to these anticancer drugs. Therapeutic efficacies of selected drugs could be increased by either increasing the drug concentration or the time of exposure of cells to drugs. Short duration of hyperthermia alone was also effective in inhibiting cell growth. Combined hyperthermia and actinomycin D or vincristine sulfate are markedly cytotoxic for the NPC cells in vitro.

Antineoplastic Agents↗

Adaptation of anticancer strategies to progress in tumor immunology.

The numerical development of cancer cells during tumor growth and under current forms of therapy is quantitatively described as a fundamental of a scientifically founded anticancer strategy. As to general cancer prevention, suppression of metastasis and reduction of recurrencies, figures are derived, which allow one to assess the minimal number of malignant cells to be killed. The killing potency of current tumor-immunological measures has not so far been sufficient enough to have a good chance of achieving these ambitious goals. The main reason for this is the neglect of the oxygen status of the body and its dynamics. This is a surprising fact, since all immunological mechanisms are known to be energy-, i.e., oxygen-dependent. The experimentally confirmed correlation between the effectiveness of body defense and the quality of the oxygen status was the origin of several variants of the oxygen multistep immunostimulation concept (application of immunostimulators combined with the oxygen multistep therapy). Clinical results reflect the remarkable increase of cell-killing potency achievable by these measures and give reasons for the adaptation of anticancer strategies to progress in tumor immunology. Furthermore, real methodological proposals are made for general cancer prevention, suppression of metastasis, and reduction of recurrences, and the concept of a combined therapy is developed. This therapy comprises the currently accepted measures, such as surgery, irradiation and drugs, and the adjuvant O2 multistep immunostimulation, which is applied threefold according to a particular schedule. The advantage of this combination is that the patient comes first into the enjoyment of all the beneficial effects that established regimens can offer for the particular case. Then and moreover, the patient gains better quality of life, because the adverse side-effects of radiation and drugs are attenuated and, finally, the individual gets a fair chance of stopping the progression of the disease.

Adjuvants, Immunologic↗

Glutamine derivatives as novel anticancer agents acting via gastrin binding sites.

With regard to the structural analogies between the C-terminal tetrapeptide of gastrin, gastrin receptor antagonists and anticancer derivatives of glutamine, it is plausible to propose that the mechanism of the anticancer activity may be related to interaction with the gastrin receptor. Dietary glutamine intake and glutamine metabolites may also influence the activity of gastrin receptors.

Animals↗

Effect of balloon occluded arterial infusion of anticancer drugs on the prognosis of cervical cancer treated with radiation therapy.

PURPOSE: The effect of local injection of anticancer drugs by balloon catheter, i.e., balloon occluded arterial infusion (BOAI), on the prognosis of cervical cancer treated with radiotherapy were retrospectively estimated. METHODS AND MATERIALS: Sixty-five patients with cervical cancer (Stage I-IV) treated by irradiation were included in the study. Among the 65 cases, 2 were in Stage I, 13 in Stage II, 40 in Stage III, and 10 in Stage IV. Patients who received surgical resection were excluded. Thirty-nine patients received BOAI and 44 received brachytherapy. Twenty-six patients were not indicated for BOAI because of insufficient renal function, hepatic complications, hematological complications, and refusal from the patients. Cisplatin (0.9-1.7 mg/kg), Adriamycin (0.7-0.9 mg/kg), and Pepleomycin (0.4-0.6 mg/kg) were administered simultaneously into the bilateral internal iliac arteries by BOAI. External irradiation was given by 10 MV x-ray. Total dose administered to the regional lymph nodes by the external irradiation was 48.3 +/- 8.7 Gy. Radium was used at brachytherapy. The dose delivered by the brachytherapy at point A was 45.3 +/- 14.9 Gy. Patients without brachytherapy received 26.1 +/- 19.1 Gy of boost irradiation by the external photon beam. The survival probabilities of the patients were calculated by Kaplan-Meier method. RESULTS: The 5-year survival rates of the Stage III patients with and without BOAI were 53 +/- 13% and 24 +/- 18%, respectively (p = 0.036). By multivariate analyses using Cox's proportional hazard model, stage and BOAI were selected as significant predictors of the prognosis. Transient bone marrow suppression was observed in about half of the patients with BOAI. No significant increase of the incidence of the late radiation damage by BOAI in rectum or in urinary bladder was observed. CONCLUSION: Balloon occluded arterial infusion of anticancer drugs may improve the prognosis of the patients with cervical cancer without increasing the incidence of the late radiation damage. A larger scale prospective randomized study is desired.

Actuarial Analysis↗

Determination of hydrophobicity of non-homologous series of anticancer drugs by reversed-phase high-performance liquid chromatography.

The hydrophobicity and specific hydrophobic surface area of 21 commercial anticancer drugs were determined by reversed-phase high-performance liquid chromatography on an octadecyl-silica column using methanol-water mixtures as eluents. Linear correlations were calculated between the log k' values and the methanol concentration of the eluent, the intercept and slope were considered as the best estimation of the hydrophobicity and specific hydrophobic surface area. The relationship between retention characteristics and physicochemical parameters of drugs was evaluated by multivariate mathematical statistical methods, such as principal component analysis followed by two-dimensional non-linear mapping, varimax rotation and by cluster analysis. Anticancer drugs can be well separated by reversed-phase HPLC. Various multivariate mathematical statistical calculations indicate that the retention of the investigated drugs is mainly governed by hydrophobic and steric parameters. The results suggest that the use of principal component analysis followed by two-dimensional non-linear mapping is superior to cluster analysis for the evaluation of large retention data matrices.

Antineoplastic Agents↗

High-performance liquid chromatographic assay for CI-980, a novel 1-deaza-7,8-dihydropteridine anticancer agent, in human plasma and urine.

CI-980, a 1-deaza-7,8-dihydropteridine, is a novel anticancer agent that is a potent mitotic inhibitor acting as a tubulin binder similar to the vinca alkaloids. CI-980 has shown equivalent or superior anticancer activity in vitro compared to vincristine and retains full activity against vincristine resistant tumors in vitro. A high-performance liquid chromatographic (HPLC) assay was developed and validated for human plasma and urine to support Phase 1 clinical trials. CI-980 and PD 080658, internal standard, were isolated from 2-ml samples of human plasma and urine by solid-phase extraction with Bond-Elut C18 cartridges. Urine samples must be pretreated with bovine serum albumin (BSA) to minimize the binding of CI-980 to glass and some plastics. The eluate from the cartridges for both matrices was evaporated to dryness and taken up in mobile phase. Zorbax RX C18 columns, mobile phase buffer of 10 mM ammonium dihydrogen phosphate at pH 7.5 and a flow-rate of 0.75 ml/min were used for both matrices. Column dimensions, column temperature and mobile phase acetonitrile-buffer ratio were 300 mm x 4.6 mm I.D., 30 degrees C and 38:62 (v/v), respectively, for the plasma assay and 250 mm x 4.6 mm I.D., 35 degrees C and 40:60 (v/v), respectively, for the urine assay. Column effluent was monitored fluorometrically for the plasma method using excitation and emission wavelengths of 388 nm and 473 nm, respectively. Ultraviolet detection at 380 nm was used for the urine method. Peak-area ratios were proportional to CI-980 concentrations from 0.2 to 25 ng/ml and 1 to 100 ng/ml for plasma and urine, respectively. CI-980 in water will bind to glass and plastics but not PTFE or stainless steel. Urine calibration standards were frozen prior to use in order to compensate for loss of CI-980 due to freezing in this matrix. The accuracy of the assay was within 4.7%, with a precision of 5.6% for both matrices. Recoveries ranged from 93.8 to 102% and 90.7 to 92.3% for plasma and urine, respectively. CI-980 was stable in plasma and urine for at least 275 and 217 days, respectively, when stored at -70 degrees C. The assay is suitable for studying the clinical pharmacokinetics of CI-980.

Antineoplastic Agents↗

Interaction of taxol and other anticancer drugs with alpha-cyclodextrin.

The interaction between 23 anticancer drugs and alpha-cyclodextrin (alpha-CD) was studied by reversed-phase charge-transfer thin-layer chromatography and the relative strength of interaction was calculated. As alpha-CD has smaller cavity than beta- and tau-CD it interacted only with 10 anticancer drugs proving the relatively poor complex forming capacity of alpha-CD. The hydrophobicity of host-guest inclusion complex was always different from that of the uncomplexed drug suggesting that the complex formation may influence the uptake, absorption, half-life etc. of the original drug. The inclusion forming capacity of drugs differed considerably according to their chemical structure. The intensity of interaction significantly depended on the hydrophobicity of the guest molecule proving the preponderant role of hydrophobic interactions in inclusion complex formation.

Antineoplastic Agents↗

Enhancement by tamoxifen of the membrane antioxidant action of the yeast membrane sterol ergosterol: relevance to the antiyeast and anticancer action of tamoxifen.

The anticancer drug tamoxifen inhibits lipid peroxidation in ox-brain phospholipid liposomes, and is a good antiyeast agent, with clinical potential. We now report that the ergosterol-containing lipid fraction derived from yeast microsomal membranes (and the ergosterol separated from it) inhibited lipid peroxidation when introduced into ox-brain phospholipid liposomes. Inhibition of lipid peroxidation by the lipid fraction was greatly enhanced when yeast cell growth was inhibited with tamoxifen prior to lipid extraction. The ability of tamoxifen to enhance the membrane antioxidant ability of ergosterol is expressed in terms of a tamoxifen enhancement coefficient. Enhancement by tamoxifen of the membrane antioxidant action of ergosterol is discussed in relation to the antifungal and anticancer actions of tamoxifen.

Animals↗

Involvement of tyrosine kinase p56/Lck in apoptosis induction by anticancer drugs.

Induction of apoptosis is a hallmark of the cellular response of human lymphocytes and lymphoma cells to treatment with anticancer drugs and irradiation. Both treatment modalities trigger apoptosis through intrinsic, mitochondrial apoptosis pathways resulting in the activation of caspases. We and others have shown that the tyrosine kinase p56/Lck is involved in the regulation of apoptosis induced by irradiation or treatment with ceramide but dispensable for death receptor triggered cell death. However, the role of p56/Lck for apoptosis induction in response to anticancer drugs is unclear. To elucidate the putative requirement of p56/Lck for apoptosis signaling of cytotoxic drugs, activation of caspases and alteration of mitochondrial functions were determined in Jurkat T cells, the p56/Lck deficient JCaM1.6 cells and the p56/Lck retransfected JCaM1.6/Lck cells in response to chemotherapeutic drugs with different targets of their primary action. Treatment with Doxorubicin, Paclitaxel or 5-Fluorouracil induced a breakdown of the mitochondrial membrane potential and apoptotic cell death in p56/Lck expressing Jurkat and the retransfected JCaM1.6/Lck cells within 48h of treatment. However, almost no mitochondrial alterations and no induction of apoptosis could be detected in the p56/Lck deficient JCaM1.6 cells. Correspondingly, activation of caspases-9, -8, and -3 and cleavage of the caspase-3 substrate PARP (poly-(ADP-ribose)-polymerase) were almost completely absent in JCaM1.6 cells while present in p56/Lck positive Jurkat and JCaM1.6/Lck cells. In contrast, retransfection of the cells with the p56/Lck-related tyrosine kinase Src could not restore sensitivity to the treatment with cytotoxic drugs indicating a specific role of the tyrosine kinase p56/Lck in apoptosis signaling. Importantly, kinase-activity of p56/Lck may be dispensable for its pro-apoptoptic action since preincubation with the Src-kinase inhibitor PP2 did not reduce apoptosis induced by cytotoxic drugs. In conclusion, the tyrosine kinase p56/Lck is essential for apoptosis induction by Doxorubicin, Paclitaxel and 5-Fluorouracil regulating early steps of the mitochondrial apoptosis signaling cascade, including alteration of mitochondrial functions and caspase-activation.

Antineoplastic Agents↗

An in vitro model system that can differentiate the stages of DNA replication affected by anticancer agents.

We have previously reported on the potential use of a novel in vitro human cell-derived model system to investigate the mechanism of action of anticancer agents that directly affect the process of DNA replication. Our cell-free system uses a multiprotein DNA replication complex (designated the DNA synthesome) that has been isolated, characterized, and extensively purified from a wide variety of mammalian cells and tissues. The DNA synthesome is competent to orchestrate simian virus 40 (SV40) origin-specific and large T antigen-dependent DNA replication in vitro. In this study, the synthesome-based cell-free system was tested to evaluate the mechanism of action of 1-beta-d-arabinofuranosylcytosine (ara-C), camptothecin (CPT), and doxorubicin (DOX). Using a novel synthesome-based in vitro kinetic assay, we demonstrated that DNA replication mediated by the synthesome is initiated within the SV40 replication origin and proceeds bidirectionally in a manner analogous to that occurring within the cell. Ara-CTP, CPT, and DOX have been found to affect different stages of the in vitro DNA replication process mediated by the complex. Ara-CTP inhibited both the initiation and elongation stages, whereas CPT produced most of its effects by inhibiting the elongation phase of DNA replication. DOX inhibited the termination stage of DNA synthesis mediated by the synthesome. The data presented here support our contention that the DNA synthesome represents a highly effective in vitro model system for investigating the mechanism by which some anticancer agents can directly affect the process of DNA replication.

Antineoplastic Agents↗

A novel cancer therapy: combined liposomal hypoxia inducible factor 1 alpha antisense oligonucleotides and an anticancer drug.

The combined influence of doxorubicin (DOX) and liposomal antisense oligonucleotides (ASOs) targeted to hypoxia-inducible factor 1 alpha (HIF1A) subunit on the apoptosis signaling pathways and cellular pump and nonpump resistance were investigated. Drug-sensitive A2780 and multidrug-resistant A2780/AD human ovarian carcinoma cells were used. Cells were incubated within 48h in normoxic (21% O(2), 5% CO(2) and 74% N(2)) or hypoxic (1% O(2), 5% CO(2) and 94% N(2)) conditions, with or without DOX in the concentration corresponding to the IC(50) dose, with or without liposomal ASO targeted to HIF1A mRNA. Apoptosis induction, lactic acid concentration, expression of genes and proteins involved in apoptosis signaling pathways, pump and nonpump cellular resistance were assessed. The results showed that overexpression of HIF1A protein induced by exposure to hypoxia and DOX activated both apoptotic cellular signal and cellular antiapoptotic defense. In addition, while hypoxia suppressed cellular pump resistance, due to multidrug resistance-associated protein family transporters, DOX activated pump resistance. A decrease in the expression of targeted protein (HIF1A) by liposomal HIF1A ASO effectively suppressed pump and nonpump cellular resistance and significantly enhanced apoptosis induction by hypoxia and DOX. Data obtained showed that ASO targeted to HIF1A mRNA that suppress cellular antihypoxic defense might be used as a powerful tool to improve the anticancer action of cytotoxic drug or even as an anticancer agent.

Apoptosis↗

Anticancer metal compounds in NCI's tumor-screening database: putative mode of action.

Clustering analysis of tumor cell cytotoxicity profiles for the National Cancer Institute (NCI)'s open compound repository has been used to catalog over 1100 metal or metalloid containing compounds with potential anticancer activity. The molecular features and corresponding reactivity of these compounds have been analyzed in terms of properties of their metals, their associated organic components (ligands) and their capacity to inhibit tumor cell growth. Cytotoxic responses are influenced by both the identity of the metal and the properties of its coordination ligand, with clear associations between structural similarities and cytotoxicity. Assignments of mechanisms of action (MOAs) for these compounds could be segregated into four broad response classes according to preference for binding to biological sulfhydryl groups, chelation, generation of reactive oxygen species (ROS), and production of lipophilic ions. Correlations between specific cytotoxic responses and differential gene expression profiles within the NCI's tumor cell panel serve as a validation for candidate biological targets and putative MOA classes. In addition, specific sensitivity toward subsets of metal containing agents has been found for certain tumor cell panels. Taken together, our results expand the knowledge base available for evaluating, designing and developing new metal-based anticancer drugs that may provide the basis for target-specific therapeutics.

Antineoplastic Agents↗

Data mining of NCI's anticancer screening database reveals mitochondrial complex I inhibitors cytotoxic to leukemia cell lines.

Mitochondria are principal mediators of apoptosis and thus can be considered molecular targets for new chemotherapeutic agents in the treatment of cancer. Inhibitors of mitochondrial complex I of the electron transport chain have been shown to induce apoptosis and exhibit antitumor activity. In an effort to find novel complex I inhibitors which exhibited anticancer activity in the NCI's tumor cell line screen, we examined organized tumor cytotoxicity screening data available as SOM (self-organized maps) (http://www.spheroid.ncifcrf.gov) at the developmental therapeutics program (DTP) of the National Cancer Institute (NCI). Our analysis focused on an SOM cluster comprised of compounds which included a number of known mitochondrial complex I (NADH:CoQ oxidoreductase) inhibitors. From these clusters 10 compounds whose mechanism of action was unknown were tested for inhibition of complex I activity in bovine heart sub-mitochondrial particles (SMP) resulting in the discovery that 5 of the 10 compounds demonstrated significant inhibition with IC50's in the nM range for three of the five. Examination of screening profiles of the five inhibitors toward the NCI's tumor cell lines revealed that they were cytotoxic to the leukemia subpanel (particularly K562 cells). Oxygen consumption experiments with permeabilized K562 cells revealed that the five most active compounds inhibited complex I activity in these cells in the same rank order and similar potency as determined with bovine heart SMP. Our findings thus fortify the appeal of mitochondrial complex I as a possible anticancer molecular target and provide a data mining strategy for selecting candidate inhibitors for further testing.

Animals↗

Absolute configuration and anticancer activity of taxiresinol and related lignans of Taxus wallichiana.

Absolute configuration of taxiresinol 1, a lignan from the heartwood of Taxus wallichiana has been determined as 8R, 8'R, and 7'R with the help of chemical correlation method and X-ray crystallography. The anticancer activity of taxiresinol 1 and other two lignans 2, 3 were also studied. Taxiresinol 1 showed notable anticancer activity in the in vitro bioassays against colon, liver, ovarian and breast cancer cell lines.

Antineoplastic Agents, Phytogenic↗

Synthesis of anticancer beta-lactams: mechanism of action.

Synthesis of the trans 1-N-chrysenyl and 1-N-phenanthrenyl 3-acetoxy-4-phenyl-2-azetidinones has been achieved. Microwave-assisted reaction has proved useful in the synthesis of these compounds. Cell growth inhibition study has indicated selective anticancer activity against two leukemia and colon carcinoma cell lines. A mechanistic correlation of their anticancer activity has been described. Striking G2 blockade that is clearly distinct in cell cycle analysis and demonstrated only in sensitive cell lines has been observed. They do not induce apoptosis in sensitive or resistant lines. They also do not inhibit topoisomerases. Ames test has shown they are nonmutagenic.

Antineoplastic Agents↗

Synthesis and anticancer activity evaluation of new 2-alkylcarbonyl and 2-benzoyl-3-trifluoromethyl-quinoxaline 1,4-di-N-oxide derivatives.

As a continuation of our research in quinoxaline 1,4-di-N-oxide and with the aim of obtaining new anticancer agents, which can improve the current chemotherapeutic treatments, new series of 2-alkylcarbonyl and 2-benzoyl-3-trifluoromethylquinoxaline 1,4-di-N-oxide derivatives have been synthesized and evaluated for in vitro antitumor activity against a 3-cell line panel, consisting of MCF7 (breast), NCI-H460 (lung), and SF-268 (CNS). These active compounds were then evaluated in the full panel of 60 human tumor cell lines derived from nine cancer cell types. The results have shown that, in general, anticancer activity depends on the substituents in the carbonyl group, improving in the order: ethyl<isopropyl<tert-butyl<phenyl-ones. Among these, the compounds 4c, 6e, their difluorinated analogs (4g and 6g), and 5c were the most active, with mean GI(50) values of 1.02, 0.42, 0.52, 0.15, and 0.49microM, respectively. All of them were also found to inhibit the growth of the all of the Leukemia cell lines studied (with 75% of the GI(50) values less than 0.15microM) and therefore, were selected for further evaluation for the in vivo hollow fiber assays.

Antineoplastic Agents↗