Effects of homo-aza-steroids on acute non-lymphocytic leukaemia cell proliferation in vitro.

Homo-aza-steroids (modified steroid molecules) in their esterified forms have been used extensively as carrier molecules of alkylating agents against several neoplastic malignancies in vivo and in vitro. We studied the effects of two homo-aza-steroid carrier molecules alone, namely 3 beta-hydroxy-13 alpha-amino-13,17-seco-5 alpha-androstan-17-oic-13, 17-lactam (compound 1) and 13 alpha-amino-13,17-seco-1,3,5-estratrien-17-oic- 13,17-lactam (compound 2), on human acute non-lymphocytic leukaemia cell proliferation in vitro. We used peripheral blood samples from 27 untreated ANLL patients (eight M1, four M2, two M3, six M4, three M5a, two M5b and two M6, according to FAB criteria). Proliferative activity was estimated by using thymidine uptake and the percentage of cells in metaphase in 24, 48 and 72 h of culture. Exposure of human leukaemic blasts with either of the two compounds resulted in enhanced cell proliferation in M1, M2, M4, M6 and M5a (only by compound 2) cases, whereas there was no significant effect in the M3 and M5b cases. Our results indicate that the two compounds tested exhibit stimulatory effect on cell proliferation, particularly in blast cells possessing a relatively smaller degree of differentiation (M1 and M6 cases exhibiting CD34 and CD7). Further research is needed to study the cell growth effect and the therapeutic potential of these steroid molecules in human blood malignancies in vitro and in vivo.

Potential antitumor agent: steroidal bilactam ester of p-N, N-bis (2-chloroethyl) aminophenylacetic acid.

7 alpha-, 17 alpha-Diaza-7, 17-dioxo-B, D-dihomo-5-androsten 3 beta-p-N, N-bis (2- chloroethyl)aminophenylacetate, a modified steroidal alkylating agent, is active in the treatment of P388 and L1210 leukemias in vivo. The compound was also tested in vitro against L1210 and P388 leukemias, on DNA, RNA and protein synthesis and showed high inhibition effect. Also increases the frequency of Sister Chromatid Exchanges and reduces the replication index of human lymphocytes.

Comparative study of SCE induction and cytostatic effects by homo-azasteroidal esters of N,N-bis(2-chloroethyl)aminobenzoic acid in human lymphocytes.

The effect of homo-azasteroidal esters of benzoic acid mustard isomers and the 4-methyl derivatives, which have steroidal lactams as a biological basis, on cytogenetic damage was studied. Twenty compounds were comparatively studied, on a molar basis, as regards their ability to induce sister-chromatid exchanges (SCEs) and cell division delays. A correlation between potency for SCE induction, effectiveness in cell division delay and previously established antitumor activity of these compounds was observed.

Comparative study on cytogenetic damage induced by homo-aza-steroidal esters in human lymphocytes.

The effect of P[N,N-bis(2-chloroethyl)amino]phenylacetate esters of 3 beta-hydroxy-N-methyl-17 alpha-aza-D-homo-5 alpha-androstan-17-one (compound 3) and 3 beta-hydroxy-17 alpha-aza-D-homo-5 alpha-androstane (compound 2) on sister-chromatid exchange (SCE) frequencies and on human lymphocytes proliferation kinetics was studied. The results are compared with those of the P[N,N-bis(2-chloroethyl)amino]phenylacetate esters of 3 beta-hydroxy-17 alpha-aza-D-homo-5 alpha-androstan-17-one (compound 1). All compounds were found to be active in inducing markedly increased SCE rates and cell division delays. A correlation between potency for SCE induction, effectiveness in cell division delay and previously established antitumour activity of these compounds was observed.

Conjugated system of homo-aza-steroidal esters in cancer chemotherapy.

The homo-aza-steroidal esters of conjugated carboxylic derivatives of nitrogen mustards are reviewed. Particularly we discuss the antitumor activity of cinnamic acid and benzoic acid mustard isomers, esters of homo-aza-steroids in which the mustard acid is linked to the C-3 or C17 position, while the lactam nucleus is in the D or A ring of the steroid respectively. The current literature indicates that the potential is due to the synergistic activity of both the steroidal lactam and the mustard of the acids. Steroidal lactams, namely 3 beta-hydroxy-13 alpha-amino-13,17-seco-5 alpha-androstan-17-oic-13,17-lactam, the isomer 3 alpha-hydroxy-13 alpha-amino-13,17-seco-5 alpha-androstan-17-oic- 13,17-lactam, 3 beta-hydroxy-13 alpha-amino 13,17-seco-5-androsten-17-oic-13,17-lactam and the 17 beta-hydroxy-3-aza-A-homo- 4 alpha-androsten-4-one, have been used as biological platforms of the cinnamic acid, of the benzoic acid mustard isomers and the 4-methyl-benzoic acid mustard. The twelve esters of cinnamic acid mustard isomers were tested against P388, L1210 leukemias Ehrlich ascites tumor (EAT) and melanoma B16 in vivo. The effect of homo-aza-steroidal esters of N,N-bis(2-chloroethyl) amino cinnamic acid isomers on the incorporation of the radioactive precursors into DNA, RNA and proteins of L1210, P388 leukemias, Ehrlich ascites tumor (EAT) and Baby Hamster Kidney (BHK) cells, was investigated. The effect of the homo-aza-steroidal esters of N,N-bis(2-chloroethyl) aminobenzoic acid isomers on the incorporation of radioactive precursors into DNA, RNA and proteins was studied in L1210, P388 leukemias, Ehrlich ascites tumor and Baby hamster kidney cells.

Comparison of current alkylating agents with a homo-aza-steroidal ester for antineoplastic activity.

The modified steroidal alkylating agent, 17 beta-hydroxy-3-aza-A-homo-4 alpha-androsten-4-one-p-bis(2-chloroethyl)aminophenoxyacetate++ + has been tested against L1210 and P388 leukemias, and Lewis lung cancer, on DNA synthesis of EAT, L1210, P388, and BHK cell cultures, and on the induction of sister chromatid exchange. Comparable studies in vivo and in vitro were also done with p-bis(2-chloroethyl)aminophenoxyacetic acid, cyclophosphamide, melphalan, and chlorambucil.

Induction of chromosomal aberrations in human lymphocytes by the antitumour alkylating agent homo-aza-steroidal ester of p-bis(2-chloroethyl)aminophenoxy acetic acid, in vitro.

The clastogenic activity of the antineoplastic alkylating agent 3 beta-hydroxy-13 alpha-amino-13,17-seco-5 alpha-androstan-17-oic-13,17-lactam- p-bis (2-chloroethyl) aminophenoxy acetic acid (NSC 294859) and its congeners was studied in human lymphocyte cultures in vitro. Cells were exposed to several concentrations of the drugs for 24 h. It was found that NSC 294859 reduces the mitotic index and causes chromosome- as well as chromatid-type aberrations in a dose-dependent way. From its congeners, the alkylating agent (p-bis(2-chloroethyl)aminophenoxy acetic acid) induces the same phenomena but to a lesser extent, while the modified steroid (3 beta-hydroxy-13 alpha-amino-13,17-seco-5 alpha-androstan-17-oic-13,17-lactam) causes cytogenetic damages at the control level. These results favour the assumption that the antitumour activity of NSC 294859 is mainly based on its cytogenetic effects.

Mutagenic activity of the antitumour agent homo-aza-steroidal ester of p-N,N-bis(2-chloroethyl)aminophenoxyacetic acid (NSC 294859) in the Salmonella/microsome assay.

The mutagenic activity of the new antitumour agent 3 beta-hydroxy-13 alpha-amino-13,17-seco-5 alpha-androstan-17-oic-13,17-lactam- p-N,N-bis(2-chloroethyl)aminophenoxyacetate (NSC 294859) was studied in the Salmonella/microsome assay. It was found to induce base pair substitutions, causing dose-dependent increases in his+ revertants in strains TA100 and TA1535. The alkylating moiety, p-N,N-bis(2-chloroethyl)-aminophenoxyacetic acid, was shown to be less effective than the parent compound, while the modified steroid moiety, 3 beta-hydroxy-13 alpha-amino-13,17-seco-5 alpha-androstan-17-oic-13,17-lactam, showed no mutagenic effect in all strains used. The presence of metabolic activation enzymes in the test system induced a further increase in his+ revertants in strains TA100 and TA1535, in both the parent compound and the alkylating moiety of the parent compound, while it had no effect in the case of the steroidal lactam.

Antitumor activity of homo-aza-steroidal esters of p-N, N-bis(2-chloroethyl)aminophenoxyacetic acid.

The homo-aza-steroidal esters of carboxylic derivatives of N, N-bis (2-chloroethyl) aniline are reviewed. In particular, we discuss the antitumor activity of the esters of homo-aza steroids in which the p-N,N-bis(2-chloroethyl)aminophenoxyacetic acid is linked to the C-3 or C-17 position, while the lactam nucleus is linked to the D or A ring of the modified steroid respectively. The current literature indicates clearly that the potential of these esters is due to the synergistic activity of both the lactam and the p-N,N-bis(2-chloroethyl)aminophenoxyacetic acid.

Structure--anticancer and structure--genetic activity relationships of homo-aza-steroidal esters of N,N-bis(2-chloroethyl)aminocinnamic acid isomers.

Four steroidal lactams of the A- and D-rings were used for the esterification in the C-3 or C-17 positions, respectively, of their nuclei with the N,N-bis(2-chloroethyl)aminocinnamic acid isomers. The condensation reaction of the hydroxylic group of the steroidal lactams with each mustard was effected in dichloromethane in the presence of the catalyst p-dimethylaminopyridine and dicyclohexylcarbodiimide as dehydrating agent. The esters were obtained in pure form after column chromatography, and their structures were verified and confirmed by analytical methods (IR and UV spectra). The 12 esters were tested in vivo against P388, L1210 leukemias, Ehrlich ascites tumor, and melanoma B16. The esters 3 alpha-hydroxy-13 alpha-amino-13,17-seco-5 alpha-androstan-17- oic-13,17-lactam-o,m,p-N,N-bis(2-chloroethyl)aminocinnamates, in which the alkylating agents are linked to the modified steroid in the axial position, are inactive in the above experimental animal tumor systems. The effect of the homo-aza-steroidal esters of N,N-bis(2-chloroethyl)aminocinnamic acid isomers on the incorporation of radioactive precursors into DNA, RNA, and proteins of L1210, P388 leukemias, Ehrlich ascites tumor, and baby hamster kidney cells was investigated. Higher inhibitory effects on the incorporation of the radioactive precursors was obtained with the ortho-derivatives, yielding > 40% inhibition of thymidine incorporation in all tumor lines tested. The effect of four esters in which the m- N,N-bis(2-chloroethyl)aminocinnamic acid is linked to the modified steroids on sister chromatid exchanges in human lymphocyte culture was investigated.

Comparative study on the mutagenicity of three structurally related substituted aniline mustards in the Salmonella/microsome assay.

The ortho, meta and para isomers of N,N-bis(2-chloroethyl)aminocinnamic acid were tested for their ability to mutate Salmonella typhimurium strains in the Salmonella/microsome mutagenicity test. The aim of the work was to establish a structure-activity relationship between these three isomers. The drugs were found to induce base-pair substitutions, causing dose-dependent increases in his+ revertants, in strains TA100 and TA1535. The study showed that the position of the substituent groups influenced the mutagenic activity of the compounds. The ortho isomer exhibited a poorer mutagenic effect than meta and this was found to be a weaker mutagen than para. The presence of metabolic activation enzymes in the test system induced a further increase in his+ revertants, in strains TA100 and TA1535, which is consistent with the findings for melphalan, a cancer chemotherapeutic agent with a chemical structure similar to that of the isomers tested.

Cytostatic effect of homo-aza-steroidal esters in vivo and in vitro. Structure-activity relationships.

The p-[N,N-bis (2-chloroethyl)amino]phenylacetate esters of 3 beta-hydroxy-N-methyl-17 alpha-aza-D-homo-5 alpha-androstan-17-one and 3 beta-hydroxy-17 alpha-aza-D-homo-5 alpha-androstane have been prepared and their antitumor activity evaluated against L1210 leukemia, P388 leukemia, Ehrlich ascites tumor (EAT) and Lewis Lung Carcinoma (LLC). The results are compared with those of the p-[N,N-bis (2-chloroethyl)amino]phenylacetate of 3 beta-hydroxy-17 alpha-aza-D-homo- 5 alpha-androstan-17-one. The above compounds were also tested in vitro against L1210, P 388, EAT and BHX cell cultures. All compounds were found to be active and their structure-activity relationship is discussed.

Hybrid anticancer compounds. Steroidal lactam esters of carboxylic derivatives of N,N-bis (2-chloroethyl) aniline (review).

For the rational design of more specific alkylating agents, we suggested new biological platforms able to deliver the alkylating moieties to specific target site and on the other hand we hoped to lead in compounds with synergistic activity. As biological platforms have been used steroidal lactams of A and D- ring and as alkylating agents carboxylic derivatives of N,N-bis (2-Chloroethyl) aniline which combine to the steroid by an easily cleaved ester bond. These homo-aza-steroidal esters gave satisfactory results in early and advanced P388, L1210 leukemias and solid tumors. Whereas unmodified steroidal esters have generally been reported to be inactive in treatment of L1210 leukemia. The steric arrangement of the alkylating moiety greatly effects toxicity and activity of the drugs, while the steric arrangement of the hydrogen atom at position 5 influences these parameters. Isosterism of alkylating agent is the factor for biological action. The amide group of the lactam molecule may be essential for activity.

Genotoxic effect of the antitumour agent homo-aza-steroidal ester of p-bis-(2-chloroethyl)aminophenoxy acetic acid (NSC 294859) tested in the Drosophila wing somatic mutation and recombination test.

The genotoxic activity of the new antineoplastic alkylating agent 3 beta-hydroxy-13 alpha-amino-13,17-seco-5 alpha-androstan-17-oic-13,17- lactam-p-bis-(2-chloroethyl) aminophenoxyacetate (NSC 294859) was studied in the somatic mutation and recombination test (SMART) in Drosophila melanogaster. The drug was administered to larvae which were transheterozygous for two recessive wing cell markers mwh and flr3. Several concentrations were tested and two of them showed a clear induction of mosaic spots, expressing the mutant phenotypes. Multiple wing hair (mwh) spots were the main type observed but twin spots and flares (flr3) spots were also detected. We conclude that the compound induces both mutations and somatic recombination in the SMART test.

Altered protein synthesis rate in ovaries of D. melanogaster caused by new antitumour alkylating agents.

1. The effect of two homo-aza-steroidal esters with antineoplastic activity, namely 3 beta-hydroxy-13 alpha-amino-13,17-seco-5 alpha-androstan-17-oic-13,17-lactam-p-bis(2-chloroethyl)aminoph enoxyacetate (NSC 294859) and 3 beta-hydroxy-13 alpha-amino-13,17-seco-5 alpha-androstan-17-oic-13,17-lactam-p-bis(2-chloroethyl)aminoph enylacetate (ASE) on protein synthesis rate was studied in ovaries of Drosophila melanogaster females. 2. Two different concentrations for each compound were examined. 3. Both esters containing the same alkylating agent have been shown to decrease protein synthesis in relation to control.

Activity of 17 beta-hydroxy-3-aza-A-homo-4 alpha-androsten-4-one-p-N, N-bis(2-chloroethyl)aminophenoxyacetate (NSC-620480) in P388 leukemia. Activity of steroidal lactams in Ehrlich tumor.

A new homo-aza-steroidal ester, 17 beta-hydroxy-3-aza-A-homo-4 alpha-androsten-4-one-p-N,N-bis(2-chloroethyl)aminophenoxyaceta te gives a T/C greater than 125% in the treatment of P388 lymphoid leukemia. Modified and unmodified steroids without alkylating congener have been studied for activity in L1210 leukemia and EAT cells.

Synergistic induction of cytogenetic damage by the homo-aza-steroidal ester of p-bis(2-chloroethyl)aminophenylacetic acid in combination with caffeine in human lymphocytes in vitro and in Ehrlich ascites tumour cells in vivo.

We studied the effects of caffeine alone or in combination with homo-aza-steroidal ester of p-bis(2-chloroethyl)aminophenylacetic acid (ASE, NSC 290205) on the frequency of SCEs and lymphocyte proliferation kinetics. Caffeine was found to act synergistically with ASE on the induction of SCEs when the two components were administered in combination. Caffeine was also found to act synergistically with ASE in inducing cell-division delays. Enhanced cytogenetic damage by ASE was observed when Ehrlich ascites tumour cells (EAT cells) were exposed in vivo to caffeine. ASE alone or in combination with caffeine caused a dose-dependent increase in SCE rates and cell-division delays. SCEs were demonstrated in EAT-bearing mice, by the i.p. injection of BrdUrd adsorbed onto activated charcoal, 1 h after the i.p. injection of ASE and/or caffeine.

Effects of alkylating antineoplastics alone or in combination with 3-aminobenzamide on genotoxicity, antitumor activity, and NAD levels in human lymphocytes in vitro and on Ehrlich ascites tumor cells in vivo.

Enhanced cytogenetic damage by the homo-aza-steroidal ester of p-bis(2-chloroethyl)-aminophenylacetic acid (ASE) was observed when human lymphocytes in vitro or Ehrlich ascites tumor (EAT) cells in vivo were exposed to nontoxic concentrations of 3-amino-benzamide (3-AB). 3-AB at these concentrations was found to enhance synergistically the cytogenetic damage induced in vivo by cyclophosphamide (CP), a metabolically activated chemotherapeutic, or chlorambucil (CBC) in EAT cells. One hour before i.p. injection of 5-bromodeoxyuridine (BrdUrd) adsorbed to activated charcoal, EAT-bearing mice treated i.p. with ASE or CP showed a dose-dependent increase in sister chromatid exchange (SCE) rates and cell division delays. The treatment of human lymphocytes in vitro with ASE led to the depletion of cellular NAD, and addition of 3-AB, a potent inhibitor of poly(ADP-ribose)polymerase [P(ADPR)polymerase], to ASE-treated human lymphocytes prevented the drop of NAD, which remained at approximately control levels. Also, the in vivo treatment of EAT cells with CBC, ASE, or CP led to the depletion of NAD, whereas addition of 3-AB to CBC-, ASE- or CP-treated cells prevented the drop of NAD, which remained at nearly control levels. 3-AB in conjunction with CBC, ASE, or CP increased the survival time of the EAT-bearing mice and markedly reduced the ascitic volume. Thus cytogenetic damage induced by ASE plus 3-AB in vitro and by CBC, ASE, or CP plus 3-AB in vivo correlates well with 1) the prevention of NAD depletion in the presence of 3-AB in cells treated with the same alkylating agents in vitro or in vivo and 2) the in vivo antitumor effect by ASE, CBC, or CP in combination with 3-AB.

Induction of sister chromatid exchanges and cell division delays in human lymphocytes by the anti-tumour agent homo-aza-steroidal ester of p-bis(2-chloroethyl)aminophenoxy acetic acid.

3 beta-Hydroxy-13 alpha-amino-13,17-seco-5 alpha-androstan-17-oic-13,17-lactam-p-bis(2-chloroethyl) aminophenoxyacetate (NSC 294859) is a new modified steroidal alkylating agent. This compound was given by i.p. administration to mice bearing different types of tumour. It was found to exhibit good activity in L1210 and P388 leukaemias with maintenance of activity against advanced tumours. The treatment of colon 26 tumour and B16 melanoma resulted in positive antineoplastic activity. The drug was not shown to be active in a melphalan-resistant P388 line. In this study, NSC 294859 was found to be effective in causing statistically significant increases in sister-chromatid exchange (SCE) rates and cell division delays. The alkylating agent component, p-bis-(2-chloroethyl)aminophenoxy acetic acid, was shown to be less effective than the parent compound, while the modified steroid component, 3 beta-hydroxy-13 alpha-amino-13,17-seco-5 alpha-androstan-17-oic-13,17-lactam, showed no effect. There were no statistically significant differences among donors regarding the induction of SCEs and replication indices (RIs) for the compounds tested.