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Total skin electron beam therapy with or without adjuvant topical nitrogen mustard or nitrogen mustard alone as initial treatment of T2 and T3 mycosis fungoides.

PURPOSE: To compare the efficacy of total skin electron beam therapy (TSEBT) with or without adjuvant topical nitrogen mustard (+/- HN2) with topical nitrogen mustard (HN2) alone as initial management of T2 and T3 mycosis fungoides (MF). METHODS AND MATERIALS: A retrospective analysis of 148 patients presenting to Stanford from January, 1970 through January, 1995 within 4 months of pathologic diagnosis of MF. Fifty-five patients with T2 and 27 with T3 disease received TSEBT +/- HN2. Fifty-four patients with T2 and 12 with T3 disease received HN2 alone. Boosts with radiotherapy were usually administered to cutaneous tumors of patients with T3 disease. RESULTS: TSEBT +/- HN2 yielded significantly higher complete response (CR) rates than did HN2 alone in patients with T2 and T3 disease (76% vs 39%, p = 0.03 for T2, and 44% vs 8%, p < 0.05 for T3, respectively). In T2 disease, treatment with adjuvant HN2 was associated with a longer freedom from relapse following TSEBT when compared to observation following a CR to TSEBT (p = 0.068). However, no significant differences in survival were observed for different management programs for T2 or T3 disease. In T2 disease, both TSEBT and HN2 were as effective as salvage therapy as when utilized as initial therapy. However, salvage therapy in T3 disease was rarely effective. Limited tumor involvement in T3 disease did not correlate with improved survival compared to more generalized tumorous disease. MF contributed to 27% and 68% of deaths in patients with T2 and T3 disease, respectively. CONCLUSION: Because of high response rates, management of significantly symptomatic or extensive T2 MF should include TSEBT, and adjuvant HN2 should be administered after a CR to TSEBT. Patients with T2 disease who fail TSEBT or HN2 can be salvaged with the other modality. TSEBT is also an effective treatment for T3 disease. The small subset of patients with limited T3 disease may also be treated with HN2 and local radiotherapy to the tumors. Further investigations are necessary to improve the overall outcome for T3 mycosis fungoides.

Administration, Topical↗

Comparative genotoxicity of nitrogen mustard and nor-nitrogen mustard.

Nitrogen mustard and nor-nitrogen mustard were investigated in Salmonella typhimurium and human lymphocytes for genotoxicity. Point mutations were assessed using the plate test, the conventional spot test and a method in which the substances were not in direct contact with the microorganisms. Both compounds were active, but nor-nitrogen mustard was far more potent than nitrogen mustard in all bacterial systems. Cytogenetic experiments with human lymphocytes revealed that both compounds induced a dose dependent increase in chromosomal aberrations and sister chromatid exchanges, but that nitrogen mustard was 10 times more potent than nor-nitrogen mustard. Thus, the spectrum of activity for nor-nitrogen mustard and nitrogen mustard differ. Nor-nitrogen mustard was more effective in inducing point mutation damage than nitrogen mustard and a reversal of potency was found for cytogenetic damage. These results indicate that although these two substances induce the same type of DNA lesions the amounts of the different DNA adducts vary.

Chromosome Aberrations↗

DNA sequence selectivity of guanine-N7 alkylation by nitrogen mustards.

Nitrogen mustards alkylate DNA primarily at the N7 position of guanine. Using an approach analogous to that of the Maxam-Gilbert procedure for DNA sequence analysis, we have examined the relative frequencies of alkylation for a number of nitrogen mustards at different guanine-N7 sites on a DNA fragment of known sequence. Most nitrogen mustards were found to have similar patterns of alkylation, with the sites of greatest alkylation being runs of contiguous guanines, and relatively weak alkylation at isolated guanines. Uracil mustard and quinacrine mustard, however, were found to have uniquely enhanced reaction with at least some 5'-PyGCC-3' and 5'-GT-3' sequences, respectively. In addition, quinacrine mustard showed a greater reaction at runs of contiguous guanines than did other nitrogen mustards, whereas uracil mustard showed little preference for these sequences. A comparison of the sequence-dependent variations of molecular electrostatic potential at the N7-position of guanine with the sequence dependent variations of alkylation intensity for mechlorethamine and L-phenylalanine mustard showed a good correlation in some regions of the DNA, but not others. It is concluded that electrostatic interactions may contribute strongly to the reaction rates of cationic compounds such as the reactive aziridinium species of nitrogen mustards, but that other sequence selectivities can be introduced in different nitrogen mustard derivatives.

Alkylation↗

Adenine-containing DNA-DNA cross-links of antitumor nitrogen mustards.

Nitrogen mustards (NMs) are useful chemotherapeutic agents in the treatment of lymphoma, leukemia, multiple myeloma, and ovarian carcinoma. The antitumor activity of NMs has been attributed to their ability to cross-link the twin strands of DNA. The resulting bifunctional lesions, if not repaired, can inhibit DNA replication and transcription, eventually leading to cell cycle arrest, apoptosis, and the inhibition of tumor growth. The predominant bifunctional DNA lesions of NM have been reported to involve the distal guanine bases in the opposite strands of 5'-GNC sequences. In the present work, the formation of guanine-adenine and adenine-adenine adducts of N,N-bis(2-chloroethyl)methylamine (mechlorethamine) in double-stranded DNA is demonstrated. Guanine-adenine cross-links of mechlorethamine were identified as N-(2-[N3-adenyl]ethyl)-N-(2-[N7-guanyl]ethyl)methylamine (N3A-N7G-EMA), N-(2-[N1-adenyl]ethyl)-N-(2-[N7-guanyl]ethyl)methylamine, and N-(2-[N(6)-adenyl]ethyl)-N-(2-[N7-guanyl]ethyl)methylamine. All three adducts were produced interstrand, while N3A-N7G-EMA was the dominant intrastrand G-A cross-link. The prevalent adenine-adenine mechlorethamine lesions have the structure of N,N-bis(2-[N3-adenyl]ethyl)methylamine (bis-N3A-EMA). DNA-derived lesions have the same HPLC retention times, UV spectra, and MS/MS fragmentation patterns as the authentic standards prepared independently. bis-N3A-EMA lesions were produced in a concentration-dependent manner in calf thymus DNA treated with increasing amounts of mechlorethamine. Furthermore, HPLC-ESI-MS/MS analysis was used to demonstrate the formation of analogous N3-N3 adenine lesions in DNA treated with aromatic nitrogen mustards, N,N-bis(2-chloroethyl)-p-aminophenylbutyric acid and L-phenylalanine mustard. The presence of cross-linked adenine-adenine lesions may explain the enhanced cytotoxicity and mutagenicity of NMs in cells deficient in N3-alkyladenine glycosylase.

Adenine↗

Stabilities of 7-alkylguanosines and 7-deoxyguanosines formed by phosphoramide mustard and nitrogen mustard.

7-Alkylguanosine and 7-alkyldeoxyguanosine were prepared from phosphoramide mustard and nitrogen mustard in nonaqueous conditions. The guanosine products were N-(2-chloroethyl)-N-[2-(7-guanosinyl)ethyl] phosphorodiamidic acid, and N-(2-chloroethyl)-N-[2-(7-guanosinyl)ethyl]methylamine, respectively. These were also formed in aqueous reactions but they rapidly underwent secondary reactions. The half-life of the phosphoramide mustard-guanosine adduct was 3.1 h (37 degrees C, pH 7.4) and that of the nitrogen mustard adduct 1 h (25 degrees C, pH 7.4), as determined by HPLC. The half-lives of the respective adducts for imidazole ring-opening were 9.5 h and 0.78 h (37 degrees C, pH 7.4). The respective deoxyguanosine derivatives depurinated with half-lives of 8.5 h and 1.6 h (25 degrees C, pH 4.2). The mustard adducts are notably more labile than simple alkyl substituted guanosines and deoxyguanosines.

Alkylation↗

Protein-DNA interactions in the human beta-globin locus control region hypersensitive site-2 as revealed by four nitrogen mustards.

Four nitrogen mustards have been used in this study to examine protein-DNA interactions in intact human cells, specifically at the locus control region hypersensitive site-2 (LCR HS-2) of the human beta-globin locus. Three of these nitrogen mustards are DNA-targeted by attachment of an acridine or amsacrine intercalating chromophore, while the fourth (chlorambucil) is a non-targeted mustard. The ligation-mediated PCR technique was used to determine the sites of damage at base pair resolution on DNA sequencing gels. A densitometric comparison was made between DNA damaged in intact erythroid K562 cells and in purified DNA. The intensity of DNA damage sites in the LCR HS-2 were found to differ significantly between intact K562 cells and purified DNA. At the NF-E2/AP-1 motif, pronounced damage protection was observed in DNA derived from drug treated cells. The nuclear factor- erythroid 2 (NF-E2) protein factor is thought to bind at this NF-E2/AP-1 motif in K562 cells. Other sites of protection and enhancement that corresponded to known transcription factor binding sites were also detected. These nitrogen mustards are therefore very effective compounds for detection of transcription factor binding to DNA in intact cells and are superior to other commonly used agents. The sequence selectivity of the compounds was determined using plasmid DNA and compared to that found in intact cells. The acridine-based nitrogen mustard had a preference for forming adducts at guanine bases, while the two amsacrine-based nitrogen mustards and chlorambucil formed adducts at both guanine and adenine bases.

Aminacrine↗

Quantitation of biomarkers of exposure to nitrogen mustards in urine from rats dosed with nitrogen mustards and from an unexposed human population.

The nitrogen mustards bis(2-chloroethyl)ethylamine (HN1), bis(2-chloroethyl)methylamine (HN2), and tris(2-chloroethyl)amine (HN3) have the potential to be used as chemical terrorism agents because of their extreme vesicant properties. We modified a previously reported method to incorporate automated solid-phase extraction, improve chromatography, and include the urinary metabolite for HN3. The improved method was used to measure levels of the urinary metabolites N-ethyldiethanolamine (EDEA), N-methyldiethanolamine (MDEA), and triethanolamine (TEA) in rats dosed with HN1, HN2, and HN3, respectively, and to establish background levels of EDEA, MDEA, and TEA in human urine samples from a population with no known exposure to nitrogen mustards. Rat dosing experiments confirmed that EDEA, MDEA, and TEA could be detected in urine for at least 48 h after exposure to HN1, HN2, and HN3, respectively. Substantial amounts of EDEA (89 ng/mL), MDEA (170 ng/mL), and TEA (1105 ng/mL) were measured in the urine of rats exposed to 10 mg HN1, HN2, and HN3, respectively, 48 h after exposure. The background concentrations for TEA in the human population ranged from below the limit of detection (LOD 3 ng/mL) to approximately 6500 ng/mL. Neither EDEA (LOD 0.4 ng/mL) nor MDEA (LOD 0.8 ng/mL) was detected above the LOD in the human samples.

Administration, Cutaneous↗

DNA damage and mutagenesis induced by nitrogen mustards.

The nitrogen mustards are bifunctional alkylating agents which, although used extensively in cancer chemotherapy, are themselves highly carcinogenic. All nitrogen mustards induce monofunctional guanine-N7 adducts, as well as interstrand N7-N7 crosslinks involving the two guanines in GNC.GNC (5'-->3'/5'-->3') sequences. In addition, the aromatic mustards melphalan and chlorambucil also induce substantial alkylation at adenine N3, while cyclophosphamide forms phosphotriesters with relatively high frequency. Nitrogen mustards are genotoxic in virtually every assay, and produce a wide array of mutations, including base substitutions at both G.C and A.T base pairs, intragenic as well as multilocus deletions, and chromosomal rearrangements. Mutational spectra generated by these agents in various model systems vary widely, and no single lesion has been implicated as being primarily responsible for mustard-induced mutagenesis. On the contrary, adducts of both adenine and guanine, and monofunctional as well as bifunctional adducts, appear to be involved. Further, it is still not known which types of mutation are responsible for mustard-induced cancers, since no genes have yet been identified which are consistently altered in these malignancies.

Animals↗

A comparison of nitrogen mustard, vincristine, procarbazine, and prednisone (MOPP) vs. nitrogen mustard in advanced Hodgkin's disease.

A randomized study of patients with advanced Hodgkin's disease was designed to determine whether the improved therapeutic effectiveness of combination chemotherapy was due to the use of a combination of drugs or might be achieved with a single agent if given as intensively and for as long a period. A combination of nitrogen mustard, vincristine, procarbazine, and prednisone (MOPP) was compared with nitrogen mustard (HN2) alone. Treatment with both regimens was given to tolerance on cylic basis and was continued for six cycles of treatment. Sixty-one evaluable patients were treated with MOPP and 47 with HN2. The complete remission rate of 47.5% with MOPP was significantly better than the 12.8% with HN2 (p less than .05). Complete remission lasted a median of 15 months after MOPP and 12 months after HN2. The survival of patients initially treated with MOPP was significantly better than that of those initially treated with HN2.

Drug Evaluation↗

Multiplicity reactivation of vaccinia virus particles treated with nitrogen mustard.

The nitrogen mustard bis(beta-chloroethyl)methylamine, a radiomimetic alkylating agent, is known for its ability to inactivate viruses in general and poxvirus in particular. These experiments show that vaccinia virus is rapidly inactivated by it. They show, in addition, that the treated virus exhibits multiplicity reactivation in L cells, closely resembling that experienced with the same virus after exposure to ultraviolet rays. These findings have come from observations of plaque titer, on the one hand, and virus particle aggregation (measured in the electron microscope), on the other. The titer of the treated virus is very sensitive to particle aggregation, increasing and decreasing in a reversible manner as the degree of clumping among the particles is changed. The magnitude of these changes is such that they must be considered in any situation involving plaque assay of the fraction of virus surviving treatment with nitrogen mustard.

Centrifugation↗