Preclinical evaluation of LU 79553: a novel bis-naphthalimide with potent antitumor activity.

LU 79553 is a novel bis-naphthalimide which is highly cytotoxic in vitro with EC50 (concentration required for 50% inhibition of growth) ranging from 2 x 10(-7) to 5 x 10(-10) M. A number of studies were conducted to examine its antitumor activity in human xenograft models. In addition, we wanted to explore the possible schedule dependency of LU 79553 cytotoxicity in these xenograft models. Complete regression of MX-1 (mammary carcinoma) xenografts was observed when LU 79553 was administered i.v. daily for 5 doses at 20 mg/kg (2 cycles starting on Days 6 and 20) or every 3 days for 2 doses at 55 mg/kg (2 cycles starting on Days 6 and 13) or every 7 days for 4 doses. Complete regression was also seen in the MX-1 model when tumors were staged at 1-2 g prior to the initiation of treatment. Regressions (complete or partial) were observed in the LX-1 (lung), CX-1 (colon), DLD (colon), and LOX (melanoma) xenograft models. A significant increase in the median survival time of OVCAR-3- (ovarian carcinoma) bearing mice was noted in LU 79553-treated animals (treated/control = 195%). The excellent activity of this compound in such a wide variety of tumor types suggests LU 79553 merits further investigation in clinical trials.

Naphthalimides as anti-cancer agents: synthesis and biological activity.

Naphthalimides are a class of compounds with high antitumor activity upon a variety of murine and human tumor cells. These compounds bind to DNA by intercalation of the chromophore and two of them, mitonafide and amonafide, were used in clinical trials. The therapeutic properties of these lead drugs were improved by designing bisintercalating agents. One of these, elinafide, showed intense in vitro and in vivo activity and is currently being used in clinical trials against solid tumors. In this paper, the history of elinafide is described.

Intercalators as anticancer drugs.

Intercalators are the most important group of compounds that interact reversibly with the DNA double helix. Some of them are valuable drugs currently used for the treatment of ovarian and breast cancers and acute leukemias, while many others are in different phases of clinical trials. Intercalating agents share common structural features such as the presence of planar polyaromatic systems which bind by insertion between DNA base-pairs, with a marked preference for 5'-pyrimidine-purine-3' steps. The chromophores are linked to basic chains that might also play an important role in the affinity and selectivity shown by these compounds. Bisintercalators have two potential intercalating ring systems connected by linkers which can vary in length and rigidity. Nowadays it is well accepted that the antitumor activity of intercalators is closely related to the ability of these compounds to stabilize the DNA-intercalator-topoisomerase II ternary complex. In this work we have carried out a revision of small organic molecules that bind to the DNA molecule via intercalation, and exert their antitumor activity through a proven topoisomerase II inhibition. We have tried to give a general overview of the most recent results in this area, paying special attention to compounds that are currently under clinical trials. Among those are naphthalimides, a group of compounds that has been developed in our laboratory since the 70's.

Chromophore-modified bis-naphthalimides: synthesis and antitumor activity of bis-dibenz[de,h]isoquinoline-1,3-diones.

The bis-dibenz[de,h]isoquinoline-1,3-diones are a new series of antitumor agents that consist of two chromophores bridged by an alkylamino linker. In the present study we have explored the effect produced by the presence of two dibenz[de,h]isoquinoline-1,3-dione moieties with different polyamine chains on cellular cytotoxicity. Bis-dibenz[de,h]isoquinoline-1,3-diones with the bridge (CH2)2-NH-(CH2)n-NH-(CH2)2, where n = 2-5, showed optimum cytotoxicity with IC50's around 10 nM. Compound 16, which has the (CH2)2-NH-(CH2)3-NH-(CH2)2 bridge, altered DNA mobility and topoisomerase I and II activity at approximately 5 microM. When tested in vivo, compound 16 increased the median survival time of mice implanted with M5076 with an optimum %T/C of 154% and produced cures in 50% of mice implanted with Lox melanoma.

Combined effect of platination and intercalation upon DNA binding of novel cytotoxic Pt-bis(naphthalimide) complexes.

The reaction of platinum salts with bis(naphthalimide), compound 1, yielded two Pt-bis(naphthalimide) complexes, compounds 2 and 3 which differ from each other in their leaving groups being 1,1-cyclobutane dicarboxylate or chloride, respectively. The testing of the cytotoxic activity of compounds 2 and 3 against several tumor cell lines indicated that both compounds may be endowed with important antineoplastic properties since they circumvent cisplatin resistance. At similar rates of DNA platination (r(b) = 0.025), compounds 2 and 3 unwind supercoiled pUC8 DNA by (48 +/- 2) degrees. Altogether, these data suggest (i) that the cytotoxic activity of compounds 2 and 3 may be due to a combined effect of platination and intercalation and (ii) that the bis(naphthalimide) ligand is a suitable "carrier" that favors DNA targeting by cis-Pt(II) centers.

Antiviral action of 5-amino-2-(2-dimethyl-aminoethyl)benzo-[de]-isoquinolin-1,3-dion e.

A newly synthesized imide derivative of 3-nitro-1,8-naphthalic acid, 5-amino-2-(2-dimethylaminoethyl)benzo-[de]-isoquinolin-1,3-dione (designated M-FA-142), was tested on chick embryo cells against herpes simplex virus type 1 (HSV-1) and vaccinia virus (VV), and on Vero cells against African swine fever virus (ASFV). At a concentration of 4 micrograms/ml the drug inhibited VV replication by about one order of magnitude, and that of HSV-1 by about three orders of magnitude. A minor effect was shown against ASFV. Virus inhibition was found to depend on the amount of drug and multiplicity of infection. No virucidal effect was observed on the viruses tested, except for a slight effect on HSV-1. Inhibition of virus growth could be reversed when the drug was removed from the cell culture medium. Serial passages of HSV-1 and VV in the presence of the drug caused the appearance of drug-resistant viruses.

Synthesis and mode(s) of action of a new series of imide derivatives of 3-nitro-1,8 naphthalic acid.

Four new imide derivatives of 3-nitro-1,8-naphthalic acid have been synthesised. The compounds show strong cytostatic activity against both HeLa and KB cells and are moderately toxic towards both mice and rats (LD50 above 4 mg/kg IP). Two of the most active compounds, M-4212 and M-12210, prevented the development of mouse Ehrlich ascites and rat Yoshida carcinoma. All these drugs block cell growth by inhibiting the synthesis of both DNA and RNA. In particular, both M-4212 and M-12210 raise the melting point of double-stranded DNA.

A new fluorescence reaction in protein cytochemistry: formation of naphthalimide fluorophores from primary amino groups and 1,8-naphthalic anhydride derivatives.

In this work we describe the formation of fluorescent naphthalimide derivatives as a new cytochemical method for revealing protein amino groups. The reaction is based on the condensation of 1,8-naphthalic anhydrides in organic solvents with primary aliphatic amines. Under optimal violet-blue (436 nm) excitation, a strong yellow-green emission is observed in specific cell components from blood smears treated with 3-amino-1,8-naphthalic anhydride in N,N-dimethylformamide, which were the most suitable reagent and solvent for microscopic studies. Cytoplasmic granules of mammalian eosinophils and avian heterophils showed the highest fluorescence reaction, which was abolished by blocking procedures for amino groups. Spectrofluorometric analysis confirmed the emission characteristics of the naphthalimides produced from n-butylamine and gelatin. Taking into account the chemical reactivity of 1,8-naphthalic anhydrides and present results, the reaction can be considered selective for lysine and arginine residues of proteins.

Fluorescence of chromatin DNA induced by antitumoral naphthalimides.

Treatment of chicken blood smears and semithin sections from Epon-embedded mouse tissues with aqueous solutions of the 3-aminonaphthalimides FA-142, FA-2043, and FA-2143 induced a strong green-yellow fluorescence of chromatin under violet or violet-blue excitation. Chromatin emission was abolished by previous DNase or hot TCA treatment. The use of 3-methoxy (FA-655) and 3-nitro derivatives (M-4212 and M-12210) resulted in very weak fluorescence of chromatin. Absorption maxima at 346 and 408 nm and an emission peak at 570 nm were observed for the free compound FA-142. Fluorescence properties open new and interesting applications for some of these antitumoral and DNA-intercalating naphthalimides.

The pharmacokinetics, tissue distribution, and biotransformation of a new class of antitumor agents: mitonafide and pinafide.

The pharmacokinetics, biotransformation, protein binding and tissue distribution of mitonafide and pinafide were studied after single i.v. and oral administration of each drug (20 mg/Kg) in female rats. In pregnant rats a study of cross placental-barrier after i.v. administration of the two drugs was also performed. The drugs were absorbed fairly rapidly with a mean peak plasma level of 7.63 +/- 0.70 micrograms eq/ml for the 3H-mitonafide and with 6.16 +/- 0.77 micrograms eq/ml for the 3H-pinafide between 30 minutes and 1 hour after oral dosing. For both drugs, the pharmacokinetics can be described by a two-compartment open model. The mean elimination half-lives were 17.8 h and 47.5 h for 3H-mitonafide and 3H-pinafide, respectively. Two metabolites for each compound as well as unchanged drugs were identified in urine by TLC and GC/MS by comparison of their chromatographic properties with a number of reference compounds. Approximately 30% of the radioactive drug was excreted over a 48 h period for 3H-mitonafide and 24% for 3H-pinafide in urine, after i.v. administration. The cross placental-barrier studies showed that both 3H-mitonafide and 3H-pinafide were present in the 14-day fetuses.

Synthesis and biological activity of new bispyridinium salts of 4,4'-bispyridyl-5,5'-perfluoroalkyl-2,2'-bisoxazoles.

A series of bispyridinium compounds were synthesized by a short sequence of reactions from symmetric diamides. All compounds were tested for their antiproliferative activity against HT-29, a cell line derived from a human colon adenocarcinoma, and their inhibitory activity against choline kinase (ChoK), a novel anticancer molecular target already in clinical trials. Most of the compounds analyzed showed good antiproliferative activities, in the micromolar range, with the identification of promising lead molecules as a new family of potential inhibitors of ChoK.

Synthesis of new derivatives of flavone-8-acetic acid.

The synthesis of new flavone-8-acetic acid derivatives is described. It is studied the influence of a dialkylaminomethyl group in the 3-position on the activity. None of the new compounds showed cytostatic activity.

[Antineoplastic drugs used as fluorochromes]. / Drogas antitumorales aplicadas como fluorocromos.

Several synthetic imide derivatives of naphthalic acid that bind to DNA and have anti-neoplastic properties are studied here in relation to the fluorescence they produce in the chromatin of chicken nucleated red blood cells.

Synthesis and biological evaluation of novel bisindolylmaleimides that inhibit vascular endothelial cell proliferation.

A novel class of bisindolylmaleimides were synthesized and antiproliferative activities (HUVECs and three tumor cell lines) of these compounds were investigated. Two water-soluble derivatives, 10 and 12, possessing a dimethylaminoalkoxy side chain in their structure, showed interesting activity and selectivity on HUVECs proliferation.

Synthesis of antitumor dendritic imides.

Dendritic imides were synthesized and evaluated as antitumor compounds. Compounds 8 and 11 showing a promising profile as inhibitors of lck but their antiproliferative activity against HT-29 was not so relevant.

Synthesis, structure and antitumor activity of new benz[d,e]isoquinoline-1,3-diones.

New benz[d,e]isoquinoline-1,3-diones related to mitonafide (CAS 54824-17-8) and amonafide (CAS 69408-81-7) with double substitution on the chromophore and branched side chains have been synthesized and their biological activity determined. Molecular modeling studies of 3a based on X-ray crystallographic data of mitonafide have shown that the aromatic system intercalates between GC steps of DNA. The in vitro cytotoxic test data using CX-1 and LX-1 cells showed higher cytotoxic activities in disubstituted derivatives compared to both lead compounds. Some of the compounds have been selected for in vivo test using L1210 tumor cells and CX-1 cells. Two of them (3b and 3j) have shown promising activity as good candidates for clinical development.

Benzimidazo[1,2-c]quinazolines: a new class of antitumor compounds.

A series of substituted benzimidazo[1,2-c]quinazolines have been synthesized. This class of compound has been designed by structural comparison with other intercalator patterns. The determination of in vitro activities has shown high inhibitory values.

Metabolism and kinetics of renal elimination of N-picolyl-3,5-dimethylbenzamides.

The metabolism and kinetics of renal elimination of N-(2-picolyl)-, N-(3-picolyl)- and N-(4-picolyl)-3,5-dimethylbenzamides were studied. These products have a depressive activity on the central nervous system, as well as an anti-inflammatory and spasmolytic activity. The elimination of the products N-(3-picolyl)- and N-(4-picolyl)-3,5-dimethylbenzamides includes a process of metabolic oxidization of the atom of pyridinic nitrogen with formation of the corresponding N-oxides as main products of its bio-transformation. The process of N-oxidization was not observed with the product N-(2-picolyl)-3,5-dimethyl-benzamide. The results showed that the renal elimination rate of the products studied is greater as the pyridinic nitrogen moves away from the amide group. In the biotransformation process of these products, there is an opposite effect, i.e., the formation of corresponding N-oxides is lower as the pyridinic nitrogen approaches the amide group.