Synthesis of (dialkylamino)alkyl-disubstituted pyrimido[5,6,1- de]acridines, a novel group of anticancer agents active on a multidrug resistant cell line

Antiproliferative and proapoptotic activities of aza-annulated naphthoquinone analogs

1,4-Naphthoquinone derivatives have been widely documented with regard to their biological properties, and particularly their anticancer activities. In the 9,10-anthraquinone family, aza-annulation involving one of the carbonyl oxygen atoms has afforded more potent, possibly less toxic analogues. We recently carried out different modifications on the naphthoquinone skeleton to generate 3-chloro-2-amino- and 3-chloro-2-(N-acetamido)-1,4-naphthoquinone and 3,4-dihydrobenzo[f]quinoxalin-6(2H)-one derivatives. These three series of compounds were now tested against normal human fibroblasts and six human cancer cell lines. Some of the dihydrobenzoquinoxalinone derivatives were not only more potent than their 1,4-naphthoquinone counterparts, but also exhibited 10- to 14-fold selectivity between bladder carcinoma and normal cells and were equipotent with the non-selective reference drug used (etoposide). The fusion of an additional azaheterocycle to the 1,4-naphthoquinone nucleus modulates both the activity, selectivity and mechanism of action of the compounds. The electrochemical properties of selected compounds were evaluated in an attempt to correlate them with cytotoxic activity and mechanism of action. Finally, 3D-QSAR CoMFA and CoMSIA models were built on the AGS, J82, and HL-60 cell lines. The best models had values of r²_pred = 0.815; 0.823 and 0.925. The main structural relationships found, suggest that acetylation and alkylation of the amino group with large groups would be beneficial for cytotoxic activity.

Antibacterial mechanism of fraxetin against Staphylococcus aureus

Fraxetin is one of the main constituents of the traditional medicinal plant Fraxinus rhynchophylla. The inhibitory effect of fraxetin on various bacterial strains has been extensively reported, however, its mechanism of action on bacterial cells remains to be elucidated. In the present study, the antibacterial mechanism of fraxetin on Staphylococcus aureus was systematically investigated by examining its effect on cell membranes, protein synthesis, nucleic acid content and topoisomerase activity. The results indicated that fraxetin increased the permeability of the cell membrane but did not render it permeable to macromolecules, such as DNA and RNA. Additionally, the quantity of protein, DNA and RNA decreased to 55.74, 33.86 and 48.96%, respectively following treatment with fraxetin for 16 h. The activity of topoisomerase I and topoisomerase II were also markedly inhibited as fraxetin concentration increased. The result of the ultraviolet‑visible spectrophotometry demonstrated that the DNA characteristics exhibited a blue shift and hypochromic effect following treatment with fraxetin. These results indicated that fraxetin had a marked inhibitory effect on S.aureus proliferation. Further mechanistic studies showed that fraxetin could disrupt nucleic acid and protein synthesis by preventing topoisomerase from binding to DNA.

Synthesis and biological evaluation of new asymmetrical bisintercalators as potential antitumor drugs

The good results obtained in the past decade with various types of potential bisintercalating agents, e.g., LU 79553, DMP 840, BisBFI, MCI3335, WMC-26, BisAC, BisPA, and the asymmetrical derivative WMC-79 (Chart 1), prompted us to investigate a new series of asymmetrical bisintercalators, compounds 1a-t (Chart 2), which can combine the potentiality of bisintercalation with a possible different mechanism of action due to two diverse chromophores. The DNA-binding properties of these compounds have been examined using fluorometric techniques: target compounds are excellent DNA ligands, with a clear preference for binding to AT-rich duplexes. In vitro cytotoxicity of these derivatives toward human hormone-refractory prostate adenocarcinoma cell line (PC-3) is described. Apoptosis assays of four selected compounds are also reported. Very potent cytotoxic compounds, some of them capable of inducing early apoptosis, have been identified.

Linker-modified triamine-linked acridine dimers: synthesis and cytotoxicity properties in vitro and in vivo

The preparation and cytotoxicity properties of a series of N(epsilon)-substituted triamine-linked acridine dimers are described. Most acridine dimer derivatives reveal highly potent in vitro cytotoxicity properties and DNA binding activity. Several acridine dimers were selected to study their action in vivo. These acridine dimers have demonstrated a narrow safe margin, as has adriamycin, but higher maximum tolerate dose (MTD) in comparison with that of adriamycin in ICR mice. The acridine dimers also demonstrated various anit-COLO 205 solid tumor activities in vivo. Compound 1 has shown the most potent solid tumor inhibition.

In vitro antileukaemic activity of extracts from berry plant leaves against sensitive and multidrug resistant HL60 cells

The aim of the present study was to determine in vitro antileukaemic activity of extracts obtained from selected berry plant leaves (Fragaria x ananassa Duch. cv Elsanta, raspberry Rubus ideus L. cv Polana and blueberry Vaccinium corymbosum L. cv Bluecrop) against promyelocytic HL60 cell line and its multidrug resistant sublines exhibiting two different MDR phenotypes: HL60/VINC (overexpressing P-glycoprotein) and HL60/DOX (overexpressing MRP1 protein). It was found that the blueberry extract was the most efficient against sensitive HL60 cell line (about 2-fold more active than strawberry and raspberry extracts) but presented much lower activity towards resistant cells. In contrast, strawberry and raspberry extracts exhibited the high cytotoxic activity against sensitive leukaemia HL60 cell line as well as its MDR sublines. The values of resistance factor (RF) found for these extracts were very low lying in the range 0.32/2.0.

Synthesis of 7-oxo-7H-naphtho[1,2,3-de]quinoline derivatives as potential anticancer agents active on multidrug resistant cell lines

Following our earlier finding that tetracyclic anthraquinone analogs with a fused pyridone ring exhibit cytotoxic activity toward multidrug resistant tumor cells, a series of new potential antitumor agents, 7-oxo-7H-naphtho[1,2,3-de]quinoline derivatives (3, 6-8, 10-12, 14, 15, and 18), bearing one or two basic side chains and various substituents at the pyridone ring, have been synthesized. The compounds have been obtained from 1-amino-4-chloroanthraquinone or 1-aminoanthraquinone by cyclization with diethyl malonate and the subsequent reactions of the key intermediates 2, 4, and 17. The compounds exhibited cytotoxic activity toward sensitive human leukemia cell line HL-60 and against its resistant sublines HL-60/VINC (MDR1 type) and HL-60/DX (MRP1 type).

2,7-Dihydro-3H-pyridazino[5,4,3-kl]acridin-3-one derivatives, novel type of cytotoxic agents active on multidrug-resistant cell lines. Synthesis and biological evaluation

We have earlier postulated that the presence of a pyridazone ring fused with an anthracenedione moiety resulted in the analog's ability to overcome multidrug resistance of tumor cells [J. Med. Chem.1999, 42, 3494]. High cytotoxic activity of obtained anthrapyridazones [Bioorg. Med. Chem.2003, 11, 561] toward the resistant cell lines, prompted us to synthesize the similarly modified acridine compounds. A series of pyridazinoacridin-3-one derivatives (2b-h) were prepared from the reaction of 9-oxo-9,10-dihydroacridine-1-carboxylate with POCl(3), followed by addition of the appropriate (alkylamino)alkylhydrazines. In vitro cytotoxic activity toward sensitive and resistant leukemia cell lines: L1210, K562, K562/DX, HL-60, HL-60/VINC, and HL-60/DX, with various type of multidrug resistance (MDR and MRP) was determined. The compounds studied exhibited in comparison to the reference cytostatics (DX, MIT) desirable very low resistance indexes (RI). Variations have been observed depending upon the substituent and the type of drug exporting pump. The cytotoxic activities of examined compounds, as well as of model anthrapyridazone derivative PDZ, were lower than those of reference drugs (DX, MIT) due to their diminished affinity to DNA.

Synthesis and evaluation of novel pyrimido-acridone, -phenoxadine, and -carbazole as topoisomerase II inhibitors

As part of a series of studies to discover new topoisomerase II inhibitors, novel pyrimidoacridones, pyrimidophenoxadines, and pyrimidocarbazoles were synthesized, and in vitro and in vivo antitumor activities and DNA-protein and/or DNA-topoisomerase II cross-linking activity as an indicator of topoisomerase II-DNA cleavable complex formation were evaluated. The pyrimidocarbazoles possessed high in vitro and in vivo potencies. Compound 26 (ER-37326), 8-acetyl-2-[2-(dimethylamino)ethyl]-1H-pyrimido[5,6,1-jk]carbazole-1,3(2H)-dione, showed in vitro growth inhibitory activity with respective IC(50) values of 0.049 microM and 0.35 microM against mouse leukemia P388 and human oral cancer KB. In vivo, this compound inhibited the tumor growth of mouse sarcoma M5076 implanted into mice with T/C values of 42% and 13% at 3.13 and 6.25 mg/kg/d respectively without significantly affecting the body weight. In addition, compound 26 (ER-37326) increased the formation of DNA-topoisomerase II cross-linking in P388 cells.

The role of structural factors in the kinetics of cellular uptake of pyrazoloacridines and pyrazolopyrimidoacridines: implications for overcoming multidrug resistance towards leukaemia K562/DOX cells

The appearance of multidrug resistance (MDR) of tumour cells to a wide array of antitumour drugs, structurally diverse and having different mechanisms of action, constitutes the major obstacle to the successful treatment of cancer. Our approach to search for non-cross resistant antitumour agents is based on the rational design of derivatives, which have a high kinetics of passive cellular uptake rendering their active efflux by MDR exporting pumps inefficient. Recently, two families of acridine cytotoxic agents were obtained, pyrazoloacridines (PACs) and pyrazolopyrimidoacridines (PPACs). The aim of this study was to examine molecular basis of the reported differences in retaining cytotoxic activity of these derivatives at cellular level against resistant erythroleukaemia K562/DOX (overexpressing P-glycoprotein) cell line. The study was performed using a spectrofluorometric method, which allows continuous monitoring of the uptake and efflux of fluorescent molecules by living cells. It was demonstrated that the presence of two additional rings, pyrazole and pyrimidine, fused to the acridine chromophore structure (PPAC) favoured more rapid cellular diffusion than the presence of only one additional pyrazole ring (PAC). The presence of hydrophobic substituent OCH3 markedly favoured the cellular uptake of pyrazoloacridines and pyrazolopyrimidoacridines while compounds having hydrophilic substituent OH exhibited very low kinetics of cellular uptake. In contrast, it was found that neither structure of the ring system nor the hydrophobic/hydrophilic character of examined substituents determined the rate of active efflux of these compounds by P-glycoprotein. Our data showed that a nearly linear relation exists between the resistance factor (RF) and lnV+ reflecting the impact of the cellular uptake rate (V+) on the ability of these compounds to overcome MDR.

Rational Design, Synthesis, and Biological Evaluation of Bis(pyrimido[5,6,1-de]acridines) and Bis(pyrazolo[3,4,5-kl]acridine-5-carboxamides) as New Anticancer Agents

The good results obtained with pyrimido[5,6,1-de]acridines 7 and with pyrazolo[3,4,5-kl]acridinecarboxamides 8 prompted us to the synthesis of two new series of bis acridine derivatives: the bis(pyrimidoacridines) 5 and the bis(pyrazoloacridinecarboxamides) 6. Compounds 5 can be regarded also as cyclized derivatives of bis(acridine-4-carboxamides) 3 and compounds 6 as cyclized derivatives of bis(acridine-4-carboxamides) 4. The noncovalent DNA-binding properties of these compounds have been examined using fluorometric techniques. The results indicate that (i) the target compounds are excellent DNA ligands; (ii) the bis derivatives 5 and 6 are more DNA-affinic than corresponding monomers 7 and 8; (iii) the new bis 5 and 6 result always less efficient in binding than related bis(acridine-4-carboxamides) 3 and 4; and (iv) in both series 5 and 6 a clear, remarkable in some cases, preference for binding to AT rich duplexes can be noted. In vitro cytotoxic potency of these derivatives toward the human colon adenocarcinoma cell line (HT29) is described and compared to that of reference drugs. Structure-activity relationships are discussed. We could identify six very potent cytotoxic compounds for further in vitro studies: a cytotoxic screening against six human cancer cell lines and the National Cancer Institute (NCI) screening on 60 human tumor cell lines. Finally, compound 6a was selected for evaluation in a NCI in vivo hollow fiber assay.

Synthesis, cytotoxicity, QSAR, and intercalation study of new diindenopyridine derivatives

Seven new derivatives of diindenopyridine were synthesized by Hantsch pyridine synthesis. Their biological activity to inhibit cell proliferation was assessed by MTT assay on seven cell lines. 11-(4-Fluoro-phenyl)-diindeno[1,2-b;2',1'-e]pyridine-10,12-dione and 11-(2-nitro-phenyl)-diindeno[1,2-b;2',1'-e]pyridine-10,12-dione were active on K-562 cell line with IC50 values of 79.66 and 78.2 microM, respectively. Effect of structural parameters on the cytotoxicity was evaluated by quantitative structure activity relationship (QSAR) analysis and a linear relationship was found between the -logIC15 of these compounds and their surface area and molar refractivity. To model the DNA-intercalator complex, force field molecular mechanic calculation was employed and the binding energy of the reaction between the intercalating agent and each reasonable double base pairs of DNA was calculated. It was found that these molecules could intercalate into the DNA. Also, it was observed that 11-(2-nitro-phenyl)-diindeno[1,2-b;2',1'-e]pyridine-10,12-dione, which showed the highest activity in K-562 cell line, produced the most negative binding energy with a moderate selectivity toward A-G/T-C double base pairs.

Rational design, synthesis and biological evaluation of thiadiazinoacridines: a new class of antitumor agents

A series of potential DNA-binding antitumor agents, 3-[omega-(alkylamino)alkyl]-6-nitro-thiadiazino[3,4,5-kl]acridines 12 and 1,3-di[omega-(alkylamino)alkyl]-6-nitro-thiadiazino[3,4,5-kl]acridines 13, has been prepared by cyclization with SOCl(2) of 1-[[omega-(alkylamino)alkyl]amino]-9-imino-4-nitro-9,10-dihydroacridines 16 or 1-[[omega-(alkylamino)alkyl]amino]-9-[omega-(alkylamino)alkyl]imino-4-nitro-9,10-dihydroacridines 17, respectively. The non-covalent DNA-binding properties of 12, 13 have been examined using a fluorometric technique. In vitro cytotoxic potencies of these derivatives toward six tumor cell lines, including human colon adenocarcinoma (HT29) and human ovarian carcinoma (A2780 sensitive, A2780cisR cisplatin-resistant, CH1, CH1cisR cisplatin-resistant, and SKOV-3) cells, are described and compared to that of reference drugs. In vivo antitumor activity of some selected derivatives, endowed with relevant cytotoxic activity against murine leukemia P388 are reported. The 3-[2-(dimethylamino)ethyl]-6-nitro-2,7-dihydro-3H-2 lambda(4)-thiadiazino[3,4,5-kl]acridin-2-one (12d) has been identified as a new lead in the development of anticancer tetracyclic acridine derivatives.

Anthrapyridones, a novel group of antitumour non-cross resistant anthraquinone analogues. Synthesis and molecular basis of the cytotoxic activity towards K562/DOX cells

1. Multidrug resistance (MDR) to antitumour agents, structurally dissimilar and having different intracellular targets, is the major problem in cancer therapy. MDR phenomenon is associated with the presence of membrane proteins which belong to the ATP-binding cassette family transporters responsible for the active drug efflux leading to the decreased intracellular accumulation. 2. The search of new compounds able to overcome MDR is of prime importance. 3. Recently we have synthesized a new family of anthrapyridone compounds. The series contained derivatives modified with appropriate hydrophobic or hydrophylic substituents at the side chain. 4. The interaction of these derivatives with erythroleukemia K562 sensitive and K562/DOX resistant (overexpressing P-glycoprotein) cell lines has been examined. The study was performed using a spectrofluorometric method which allows to continuously follow the uptake and efflux of fluorescent molecules by living cells. 5. It was demonstrated that the increase in the lipophilicity of anthrapyridones favoured the very fast cellular uptake exceeding the rate of P-gp dependent efflux out of the cell. For these derivatives, very high accumulation (the same for sensitive and resistant cells) was observed and the in vitro biological data confirmed that these compounds exhibited comparable cytotoxic activity towards sensitive and P-gp resistant cell line. In contrast, anthrapyridones modified with hydrophylic substituents exhibited relatively low kinetics of cellular uptake. 6. For these derivatives decreased accumulation in resistant cells was observed and the in vitro biological data demonstrated that they were much less active against P-gp resistant cells in comparison to sensitive cells. 7. We also studied, using confocal microscopy, the intracellular distribution of anthrapyridones in NIH-3T3 cells. Our data showed that these compounds were strongly accumulated in the nucleus and lysosomes.

2,6-Di(omega-aminoalkyl)-2,5,6,7-tetrahydropyrazolo[3,4,5-mn]pyrimido[5,6,1-de]acridine-5,7-diones: novel, potent, cytotoxic, and DNA-binding agents

DNA-binding agents with potential antitumor activities bearing two cationic side chains, the 2,6-di(omega-aminoalkyl)-2,5,6,7-tetrahydropyrazolo[3,4,5-mn]pyrimido[5,6,1-de]acridine-5,7-diones (4a-r), have been prepared either by reaction of the appropriate 2-(omega-aminoalkyl)-6-chloro-2,3-dihydro-1H,7H-pyrimido[5,6,1-de]acridine-1,3,7-trione with the appropriate (omega-aminoalkyl)hydrazine or by cyclization of the requisite N-6,2-di(omega-aminoalkyl)-2,6-dihydropyrazolo[3,4,5-kl]acridine-6-carboxamide with phosgene. In vitro cytotoxic properties of these derivatives against three human colon adenocarcinoma cell lines (HT29, LoVo, and LoVo/Dx) and against some cell lines of the NCI panel are described and compared to that of reference drugs. Some of the new compounds showed outstanding potency while lacking cross-resistance with anthracyclines. Structure-activity relationships are discussed, and a mechanistic analysis is performed using the COMPARE procedure. The mechanism and efficiency of noncovalent DNA binding of these compounds are examined using gel electrophoresis and fluorometric techniques. The 2,6-di(omega-aminoalkyl)-2,5,6,7-tetrahydropyrazolo[3,4,5-mn]pyrimido[5,6,1-de]acridine-5,7-diones (4) constitute a new class of potent, cytotoxic DNA-binding agents not cross-resistant with doxorubicin.

Synthesis and cytotoxic activity of 7-oxo-7H-dibenz[f,ij]isoquinoline and 7-oxo-7H-benzo[e]perimidine derivatives

A series of 7-oxo-7H-dibenz[f,ij]isoquinoline and 7-oxo-7H-benzo[e]perimidines bearing cationic side chains were prepared from aminoanthraquinones. The perimidines were prepared from 1-aminoanthraquinone by initial condensation with urea or dimethylacetamide. A series of 2-, 4-, 8-, and 11-carboxy derivatives of the dibenzisoquinolines were prepared from aminoanthraquinonecarboxylic acids. The cationic derivatives were prepared from these via amide, amine, or methylene linkers to study the effects of side chain positioning on biological activity. Within the series of carboxamide-linked compounds, the order of increasing cytotoxicity was 8- < 4- < 2- < 11-. The 2- and 4-carboxamides showed substantial growth delays against in vivo subcutaneous colon 38 tumors in mice, but the 11-carboxamide had curative activity in this refractory model and is being investigated further.

N4-(omega-Aminoalkyl)-1-[(omega-aminoalkyl)amino]-4- acridinecarboxamides: novel, potent, cytotoxic, and DNA-binding agents

A series of DNA-binding potential antitumor agents, (omega-aminoalkyl)-4-acridinecarboxamides, has been prepared either by reduction of the corresponding (omega-aminoalkyl)-9-oxo-9, 10-dihydro-4-acridinecarboxamides with aluminum amalgam or by aminolysis of the corresponding (omega-aminoalkyl)-1-chloro-4-acridinecarboxamides with the suitable amine. The noncovalent DNA-binding properties of these compounds have been examined using a fluorometric technique. In vitro cytotoxic potencies of these derivatives toward six tumor cell lines, including human colon adenocarcinoma (HT29) and human ovarian carcinoma (A2780-sensitive, A2780cisR cisplatin-resistant, CH1-sensitive, CH1cisR cisplatin-resistant, and SKOV-3) cells, are described and compared to that of reference drugs. One highly DNA affinic analogue (3a) has been identified with a useful broad spectrum of cytotoxic activity in the 4-7 nM range (mean IC(50) of 6 nM).

Synthesis and cytotoxic activity of 2-dialkylaminoethylamino substituted xanthenone and thioxanthenone derivatives

The synthesis and biological evaluation of some new pyranoxanthenones and pyranothioxanthenones, substituted with flexible amino side-chains, and their evaluation as potential antitumor agents is described. The cytotoxic activity of the compounds and their eventual selective effect on a phase of the cell cycle were evaluated in vitro, using the murine lymphocytic L1210 leukemia cell line. The new aminoderivatives exhibited highly potent cytotoxicity against the leukemia L1210 cell line when compared to acronycine. All the compounds induced a partial accumulation of cells in the G2 + M phase of the cell cycle.

8,11-dihydroxy-6-[(aminoalkyl)amino]-7H-benzo[e]perimidin-7-ones with activity in multidrug-resistant cell lines: synthesis and antitumor evaluation

The synthesis of dihydroxybenzoperimidine derivatives, which are chromophore-modified dihydroxyanthracenediones with an additional pyrimidine ring incorporated into the chromophore, is reported. These derivatives are structurally related to the antitumor agent mitoxantrone. Their synthesis was carried out by the reaction of 6-amino-8,11-dihydroxy-7H-benzo[e]perimidin-7-one (5) or 6,8, 11-trihydroxy-7H-benzo[e]perimidin-7-one (10) with a number of respective (alkylamino)alkylamines. The dihydroxybenzoperimidine derivatives exhibited in vitro cytotoxic activity against murine leukemia L1210 and human leukemia HL60 cell lines comparable to that of mitoxantrone. These compounds also exhibited a range of in vitro activity against the human MDR-type resistant leukemia K562R cell line with the MDR phenotype. The most active compound of this series, namely 6a, exhibited potent in vitro cytotoxic activity against a panel of human cell lines. Furthermore, in contrast to both mitoxantrone and doxorubicin, it displayed little cross-resistance in cell lines characterized by a MDR phenotype. Cell cycle analysis in the sensitive HT-29 and mitoxantrone-resistant HT-29/Mx (not identified resistance mechanism) cell lines has revealed that both mitoxantrone and 6a induce a G2/M block. However, while the proportion of apoptotic cells after mitoxantrone treatment is similar for both sensitive and resistant cell lines, it is much lower for 6a. Compound 6a tested against P388 murine leukemia in vivo displayed a significant antitumor effect (%T/C 196 at an optimal dose of 10 mg/kg). The property of overcoming the cross-resistance was maintained also in in vivo efficacy studies, where no difference was observed in the antitumor activity of compound 6a against the A2780 human tumor xenograft and its MDR A2780/Dx subline. We conclude that benzoperimidines, if properly substituted, constitute a novel class of compounds that can overcome multidrug resistance.

2,3-Dihydro-1H,7H-pyrimido[5,6,1-de]acridine-1,3,7-trione derivatives, a class of cytotoxic agents active on multidrug-resistant cell lines: synthesis, biological evaluation, and structure-activity relationships

A series of DNA-intercalating potential antitumor agents, (amino)alkyl-substituted 2,3-dihydro-1H,7H-pyrimido[5,6, 1-de]acridine-1,3,7-triones, has been prepared by aminolysis of the corresponding 6-chloro derivative with a suitable omega-aminoalkylamine. The noncovalent DNA-binding properties of these compounds have been examined using a fluorometric technique. In vitro cytotoxic potencies of these derivatives toward eight tumor cell lines, including human colon adenocarcinoma (HT29, LoVo sensitive and LoVo/Dx (doxorubicin-resistant)) and human ovarian carcinoma (A2780 sensitive, A2780cisR (cisplatin-resistant), CH1, CH1cisR (cisplatin-resistant), and SKOV-3) cells, are described and compared to that of reference drugs. The cytotoxic activity often parallels the observed DNA affinities, for almost all the target compounds. Interesting structure-activity relationships have been found. The octanol/water partition coefficients have also been calculated, but there was no correlation either with cytotoxicity values or with resistance index. Three highly DNA-affinic analogues, 9 and 15f,15h, have been identified with a useful broad spectrum of cytotoxic activity.

1-[(omega-aminoalkyl)amino]-4-[N-(omega-aminoalkyl)carbamoyl]-9-oxo-9, 10-dihydroacridines as intercalating cytotoxic agents: synthesis, DNA binding, and biological evaluation

A series of DNA-intercalating potential antitumor agents, 1-[(omega-aminoalkyl)amino]-4-[N-(omega-aminoalkyl)carbamoyl]-9-oxo-9, 10-dihydroacridines, has been prepared by aminolysis of the corresponding 4-[N-(omega-aminoalkyl)carbamoyl]-1-chloro derivative with a suitable omega-aminoalkylamine. The noncovalent DNA-binding properties of these bis-functionalized compounds have been examined using a combination of fluorometric and thermal denaturation techniques and are compared with the behaviors for established DNA intercalants and cationic minor groove ligands. The results indicate that (i) the agents are considerably more DNA-affinic than less functionalized acridinones, with 'apparent' binding constants of (0.1-2.1) x 10(7) and (0.3-7.5) x 10(7) M-1 at pH 5 and 7, respectively, (ii) overall affinity is sensitive to both the length of the flexible side chain and the complexity of the attached amine substituents, and (iii) the pendant side chains effect a switch to moderate AT-preferential binding. In vitro cytotoxic potencies toward six tumor cell lines broadly parallel the observed DNA affinities, although poor correlation is evident for certain compounds. The octanol/water partition coefficients have been also calculated, but there is no correlation with cytotoxicity values. Two highly DNA-affinic analogs, 10 and 13, have been identified with a useful broad spectrum of cytotoxic activity.