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K D Paull

Publications and source records attributed to K D Paull.

52 records · Page 3Linked to original sources

Computer-assisted structure--anticancer activity correlations of carbamates and thiocarbamates.

With the aid of the computer, approximately 8000 compounds that incorporate a carbamate or thiocarbamate moiety, which have been tested as potential anticancer agents at the National Cancer Institute (NCI), were classified and their structure-activity correlations against the in vivo P-388 and L-1210 leukemias were evaluated. Aromatic carbamates and thiocarbamates have shown good activity against P-388 and poor activity against L-1210. The majority of active compounds in this series of aromatic carbamates possess a 2- or 4-heteroatom-substituted phenyl attached to the carbamate oxygen atom or the thiocarbamate sulfur atom with the carbamate nitrogen atom as NHMe. The N-phenyl carbamates were much less active against P-388 than the phenyl carbamates; only bis-N-phenyl carbamates with a methylene bridge between the two phenyl groups showed good activity against both P-388 and L-1210 leukemias. Except for the mycophenolic acid carbamates, the fused phenyl carbamates showed poor activity against both P-388 and L-1210 leukemias. Certain nitrogen-heterocyclic carbamates and carbamates with heteroatom substituents have been selected by the NCI for development toward clinical trials. The nature of the heterocyclic carrier and the position of attachment to the carbamate moiety have a major role on the mode of action of the antitumor activity of these compounds.

Animals↗

Activity of a novel 4-quinolinecarboxylic acid, NSC 368390 [6-fluoro-2-(2'-fluoro-1,1'-biphenyl-4-yl)-3-methyl-4-quinolinecarb oxylic acid sodium salt], against experimental tumors.

A novel, substituted 4-quinolinecarboxylic acid (NSC 339768) demonstrated antitumor activity against L1210 leukemia and B16 melanoma in the National Cancer Institute's Developmental Therapeutics Program. An extensive analogue synthesis program was initiated; over 200 derivatives were synthesized and tested for anticancer activity. One of these compounds, 6-fluoro-2-(2'-fluoro-1,1'-biphenyl-4-yl)-3-methyl-4-quinolinecarboxylic acid sodium salt, NSC 368390 (DuP-785), was selected for further investigation because of its efficacy against a spectrum of human solid tumors and its water solubility. In initial studies with L1210 leukemia, the compound caused an increase in life span of greater than 80%. The activity was schedule dependent, and the compound was equally efficacious when administered i.p., i.v., s.c., or p.o. In tests against human tumors xenografted under the renal capsule of nude mice, NSC 368390 when injected i.p. in doses of 20-40 mg/kg daily for 9 days inhibited the growth of the MX-1 breast, LX-1 lung, BL/STX-1 stomach, and CX-1 colon carcinomas by greater than 90%. NSC 368390 also inhibited the growth of three distinct human colon carcinomas, the HCT-15, clone A, and DLD-2 tumors, growing s.c. in nude mice. An i.p. dose of 25 mg/kg given daily for 9 days inhibited the growth of the DLD-2 colon cancer by 98%. 1-beta-D-Arabinofuranosylcytosine and Adriamycin were ineffective, and fluorouracil was only moderately effective against these colon tumors. Because of its good activity against human colon tumors and other human carcinomas and its water solubility, NSC 368390 (DuP-785) is being developed as a Phase 1 anticancer agent.

Animals↗

Computer-assisted structure-activity correlations.

Several types of Michael acceptors, including alpha,beta-unsaturated ketones, lactones, and lactams, have been extensively studied as potential anticancer agents. A concerted effort was made to explore the relationship between the structures of these compounds and their antitumor activity against P388 and L1210 leukemias. This article describes the computer-assisted structure-activity evaluation of more than 14,000 compounds, representing different classes of Michael acceptors, in the NCI file. In this study, advantage has been taken of the computer's ability to search substructures according to precise definitions and to manipulate these substructures utilizing Boolean logic. Olefinic conjugated Michael-type acceptors, e.g., styrenes with different activating groups, cinnamic acid derivatives, and alpha,beta-unsaturated nitro, cyano, sulfone, sulfoxide, and acetylenic compounds, have shown appreciable activity against P388 lymphocytic leukemia. The analysis of lactones and lactams includes substructures representing a wide variety of exocyclic and endocyclic alpha,beta-unsaturated compounds. The analysis describes the effect of certain groups, such as an --OH, --OR, alpha,beta-unsaturated ester, or epoxide, adjacent to the alpha,beta-unsaturated center, on the antitumor activity of these compounds. A combination of one or more of these activating groups with an alpha-methylene-gamma-lactone moiety significantly enhanced the activity against P388. In general, many of the classes of compounds studied have shown poor activity against the more stringent L1210 lymphoid leukemia.

Antineoplastic Agents↗

Computer assisted structure-activity correlations. Evaluation of benzo(de)isoqinoline-1,3-diones and related compounds as antitumor agents.

Computer assisted evaluations of benzo(de)isoquinoline-1,3-diones and related compounds screened for antitumor activity against P388 lymphocytic leukemia and L1210 lymphoid leukemia are presented. Two important features necessary for good anticancer activity are the nature of the imide side-chain and the type of substituent on the aromatic portion. Based on these considerations 1H-benzo(de)isoquinoline-1,3(2H)dione,5-amino-2-(2-dimethyl-aminoethyl) (NSC 308847) has been selected for preclinical toxicology studies.

Animals↗

Some substituted naphthazarins as potential anticancer agents.

Some 2,3-bis(substituted methyl)naphthazarins and related compounds were synthesized by the Diels-Alder reaction of benzoquinone and 2,3-dimethylbutadiene followed by oxidation and substitution reactions. These compounds were prepared as potential biological alkylating agents. Screening results indicated that 1,4-diacetyl-6,7-dimethyl-4a,5,8,8a-tetrahydronaphthalene and 5,8-bis(benzoyloxy)-2,3-dimethyl-1,4-naphthoquinone possessed borderline activity against leukemia P388 and that naphthazarin diacetate possessed confirmed cytotoxicity against the cell culture of human epidermoid carcinoma of the nasopharynx.

Animals↗

A protein expression database for the molecular pharmacology of cancer.

In the last six years, the Developmental Therapeutics Program (DTP) of the US National Cancer Institute (NCI) has screened over 60,000 chemical compounds and a larger number of natural product extracts for their ability to inhibit growth of 60 different cancer cell lines representing different organs of origin. Whereas inhibition of the growth of one cancer cell type gives no information on drug specificity, the relative growth inhibitory activities against 60 different cells constitute patterns that encode detailed information on mechanisms of action and resistance (as reviewed in Boyd and Paull, Drug Devel. Res. 1995, 34, 19-109 and Weinstein et al., Science 1997, 275, 343-349). In order to correlate the patterns of activity with properties of the cells, we and other laboratories are characterizing the cells with respect to a large number of factors at the DNA, mRNA, and protein levels. As part of that effort, we have developed a two-dimensional gel electrophoresis (2-DE) protein expression database covering all 60 cell types (Buolamwini et al., submitted). Here we present analyses of the correlations among protein spots (i) in terms of their patterns of expression and (ii) in terms of their apparent relationships to the pharmacology of a set of 3989 screened compounds. The correlations tend to be stronger for the latter than for the former, suggesting that the spots have more robust signatures in terms of the pharmacology than in terms of expression levels. Links to pertinent databases and tools of analysis will be updated progressively at http:@www.nci.nih.gov/intra/lmp/jnwbio.htm and http:@epnwsl.ncifcrf.gov:2345/dis3d/dtp.++ +html.

Antineoplastic Agents↗

Discrimination techniques applied to the NCI in vitro anti-tumour drug screen: predicting biochemical mechanism of action.

The National Cancer Institute currently tests approximately 400 compounds per week against a panel of human tumour cell lines in order to identify potential anti-cancer drugs. We describe several approaches, based on these in vitro data, to the problem of identifying the primary biochemical mechanism of action of a compound. Using linear and non-parametric discriminant procedures and cross-validation, we find that accurate identification of the mechanism of action is achieved for approximately 90 per cent of a diverse collection of 141 known compounds, representing six different mechanistic categories. We demonstrate that two-dimensional graphical displays of the compounds in terms of the initial three principal components (of the original data) result in suggestive visual clustering according to mechanism of action. Finally, we compare the classification accuracy of the statistical discrimination procedures with the accuracy obtained from a neural network approach and, for our example, we find that the results obtained from the various approaches are similar.

Antineoplastic Agents↗

Mining the NCI anticancer drug discovery databases: genetic function approximation for the QSAR study of anticancer ellipticine analogues.

The U.S. National Cancer Institute (NCI) conducts a drug discovery program in which approximately 10,000 compounds are screened every year in vitro against a panel of 60 human cancer cell lines from different organs of origin. Since 1990, approximately 63,000 compounds have been tested, and their patterns of activity profiled. Recently, we analyzed the antitumor activity patterns of 112 ellipticine analogues using a hierarchical clustering algorithm. Dramatic coherence between molecular structures and activity patterns was observed qualitatively from the cluster tree. In the present study, we further investigate the quantitative structure-activity relationships (QSAR) of these compounds, in particular with respect to the influence of p53-status and the CNS cell selectivity of the activity patterns. Independent variables (i.e., chemical structural descriptors of the ellipticine analogues) were calculated from the Cerius2 molecular modeling package. Important structural descriptors, including partial atomic charges on the ellipticine ring-forming atoms, were identified by the recently developed genetic function approximation (GFA) method. For our data set, the GFA method gave better correlation and cross-validation results (R2 and CVR2 were usually approximately 0.3 higher) than did classical stepwise linear regression. A procedure for improving the performance of GFA is proposed, and the relative advantages and disadvantages of using GFA for QSAR studies are discussed.

Algorithms↗

Mining and visualizing large anticancer drug discovery databases.

In order to find more effective anticancer drugs, the U.S. National Cancer Institute (NCI) screens a large number of compounds in vitro against 60 human cancer cell lines from different organs of origin. About 70,000 compounds have been tested in the program since 1990, and each tested compound can be characterized by a vector (i.e., "fingerprint") of 60 anticancer activity, or -[log(GI50)], values. GI50 is the concentration required to inhibit cell growth by 50% compared with untreated controls. Although cell growth inhibitory activity for a single cell line is not very informative, activity patterns across the 60 cell lines can provide incisive information on the mechanisms of action of screened compounds and also on molecular targets and modulators of activity within the cancer cells. Various statistical and artificial intelligence methods, including principal component analysis, hierarchical cluster analysis, stepwise linear regression, multidimensional scaling, neural network modeling, and genetic function approximation, among others, can be used to analyze this large activity database. Mining the database can provide useful information: (a) for the development of anticancer drugs; (b) for a better understanding of the molecular pharmacology of cancer; and (c) for improvement of the drug discovery process.

Algorithms↗

Antineoplastic agents. 76. The sea urchin Strongylocentrotus droebachiensis.

An improved procedure based on centrifugation at 37,000 g has been developed for isolating the antineoplastic glycoprotein strongylostatin 1 from Strongylocentrotus droebachiensis (Müller). The green sea urchin has also been found to contain a second protein anticancer constituent designated strongylostatin 2. Treatment of the murine P388 lymphocytic leukemia with strongylostatin 2 resulted in 39-42% life extension at a dose of 4.5 mg/kg.

Animals↗