Induction of mutant lymphocytes in cyclophosphamide- and chlorambucil-treated patients

Abstract

Monitoring patients treated with single antineoplastic agents is aiding our understanding of what hazard these drugs pose in vivo. In this study, the frequency of mutant 6-thioguanine-resistant (TG(R)) peripheral blood lymphocytes was monitored before treatment and for < or =35 weeks after treatment of patients with cyclophosphamide (CP) or chlorambucil (CAB). The mean mutant frequency before treatment for six multiple sclerosis patients treated with high-dose CP was 2.53 x 10(-5) and increased after treatment to 4.61 x 10(-5) (P = 0.08, paired t-test). Using each patient as their own control, there were significant increases (each at P < 0.04) detectable within 2-4 weeks in four of the multiple sclerosis patients treated with CP. There was no increase in an untreated control monitored over the same period. In a patient receiving five sequential CP treatments at 1 month intervals, there were cumulative increases in the frequency of mutant cells. The mutant frequency increased from 0.31 x 10(-5) before treatment to 3.64 x 10(-5) after the final treatment and had decreased to 0.53 x 10(-5) at 35 weeks after treatment. In one of two CAB-treated patients with indolent non-Hodgkin's lymphoma, there was a significant increase in mutant frequency (P < 0.03) after treatment. Freshly isolated peripheral blood lymphocytes treated with 4-hydroperoxy-CP in vitro demonstrate a dose-dependent increase in mutant frequency. The increment in mutant frequency observed in vivo is of the order expected from the in vitro experiments. Although this study demonstrates that single or multiple doses of a single antineoplastic agent are mutagenic in vivo for some patients, further studies are needed to determine the extent and mechanism of the inter-individual variations in mutagenic response.

Assessment of Chemoselective Neoglycosylation Methods Using Chlorambucil as a Model

“…A nitrogen mustard, 1 leads to guanine alkylation and DNA cross-linking, and ultimately prohibits DNA replication and transcription 32–33. The primary cellular uptake mechanism of 1 is passive diffusion34 and like many cytotoxics, the lack of nitrogen mustard tumor-specificity contributes to serious side effects 35,36. Thus, improvements have focused upon i) the development of tumor-activated prodrugs – exemplified by the hypoxia-activated N -oxide PX-478 (Figure 1, 2 ) currently in phase I;37 or ii) modifications to engage tumor-specific transport – exemplified by the β- D -glucosyl analog of ifosfamide (glufosfamide, Figure 1, 4 ) which is actively transported into tumor cells by the sodium/ D -glucose cotransporter SGLT3 (SAAT1) 38.…”

“…First synthesized over 5 decades ago, chlorambucil remains a current treatment for chronic lymphocytic leukemia (CLL) − a Abbreviations: BH 3 ·Et 3 N, borane−triethylamine complex; CLL, chronic lymphocytic leukemia; CNS, central nervous system; DIC, N , N ′-diisopropylcarbodiimide; DMAP, 4-( N ′, N ′-dimethylamino)pyridine; EDAC, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide; GI 50 , growth inhibitory concentration for 50% of the cell population under study; GLUT1, glucose transporter 1; LAH, lithium aluminum hydride; NMM, N -methylmorpholine; SAAT1, sodium/amino acid transporter 1; SGLT3, sodium/glucose transporter 3; SPE, solid phase extraction; THF, tetrahydrofuran. and has served as the basis for newer generation analogues such as the recently approved bendamustine ( 3 ) . A nitrogen mustard, 1 leads to guanine alkylation and DNA cross-linking and ultimately prohibits DNA replication and transcription. , The primary cellular uptake mechanism of 1 is passive diffusion, and like many cytotoxics, the lack of nitrogen mustard tumor-specificity contributes to serious side effects. , Thus, improvements have focused upon (i) the development of tumor-activated prodrugs, exemplified by the hypoxia-activated N -oxide PX-478 (Figure , 2 ) currently in phase I or (ii) modifications to engage tumor-specific transport, exemplified by the β- d -glucosyl analogue of ifosfamide (glufosfamide, Figure , 4 ) which is actively transported into tumor cells by the sodium/ d -glucose cotransporter SGLT3 (SAAT1) . While the specific glycosylation of 1 has presented analogues that display slight improvements in a perceived therapeutic index (slightly improved in vitro potency and subtle reductions of in vivo peripheral toxicity), the analogues synthesized to date have been restricted to the use of d -gluco- or d -galacto-based sugars. − …”

Simultaneous determination of low levels of methotrexate and cyclophosphamide in human urine by micro liquid chromatography/electrospray ionization tandem mass spectrometry

“…The cytotoxic effects of chemotherapeutic drugs (interaction and cross linking with the DNA cells, inhibition of protein or nucleic acid synthesis and DNA‐transcribing enzymes, interferences in replication of genetic material) are known to affect healthy cells as well. Several clinical studies have in fact shown an increase in secondary tumors in patients treated with these substances 1, 2. For this reason, hospital personnel who handle cytostatic drug mixtures are exposed to a risk of adverse health effects.…”

Alteration in the laboratory profile of a lupus anticoagulant in a patient with non-Hodgkin's lymphoma

“…Tumours from NHL patients treated with monoclonal anti-idiotype antibody and chlorambucil have been described with mutated idiotypes (Davis et al, 1998). Point mutations are seen over time in B-cell malignancies (Levy et al, 1987) and use of single antineoplastic agents has been shown to increase lymphocyte mutation frequency in vivo for some patients (Sanderson, Johnson & Henner, 2001). However, in the absence of any follow-up immunofixation to demonstrate the appearance/disappearance of a monoclonal IgM that mirrors the ACA results, this assertion cannot be proven.…”