Abstract
Using the pZ189 shuttle vector approach, we determined two chloroethylcyclohexyl-nitrosourea (CCNU)-induced mutation spectra (3 and 6 mM) in African green monkey kidney cells (CV1). One hundred and twenty-one independent clones (101 CCNU induced, 45 at 3 mM and 56 at 6 mM; 20 spontaneous) showing functional inactivation of the supF gene were analyzed. One hundred and five plasmids (91 CCNU induced, 41 at 3 mM and 50 at 6 mM; 14 spontaneous), showing no large deletion/rearrangements, were sequenced. Ninety mutants (81 CCNU induced and 9 spontaneous) showed at least one mutation in the supF region. The analysis of the 122 CCNU-induced mutations (56 and 66 at 3 and 6 mM, respectively) revealed that: (a) the majority of the mutations were GC-targeted base pair substitutions; (b) AT-targeted mutations were significantly more frequent in the CCNU-induced (6 mM) than in the spontaneous mutational spectrum (P <0.0006, Fisher's exact test); (c) mutational spectra obtained at 3 and 6 mM CCNU were significantly different (P <0.008); (d) induced mutations were nonrandomly located in both spectra and generated either a common hot spot (position 123, 5′-GGG-3′) or hot spots exclusive for each CCNU concentration (3 mM: position 159,5′-AGG-3′; 6 mM: position 109,5′-GGG-3′); (e) the occurrence of GC→ AT transitions was significantly different as a function of CCNU concentration (P <0.02, Fisher's exact test), the mutated G being almost exclusively preceded by a purine (5′Pu G) at 6 mM and by either Pu or Py at 3 mM; and (f) by applying Calladine's rules, we found that sequences encompassing the three CCNU hot spots shared identical helix parameters for no more than 2 bp steps 5′ (or 3 bp steps 3′) to the mutated G. Our results are consistent with the hypothesis that O6-alkylguanine is responsible, either directly or indirectly, for the majority of GC-targeted mutations, while O4-alkylthymine and/or N3-alkyladenine are probably responsible for AT-targeted mutations. The results suggest also that, in CV1 cells, the efficiency of the repair mechanism(s) involved in the removal of O6-alkylguanine is influenced by the DNA sequence context All of these factors determine the CCNU mutational fingerprint. CCNU has been implicated in the induction of therapy-related leukemias. The work presented here could be a valuable tool to verify this hypothesis at the molecular level by comparing the CCNU fingerprint with the p53 mutational spectrum obtained in patients formerly treated with CCNU and affected by a therapy-related leukemia.
| Original language | English |
|---|---|
| Pages (from-to) | 4658-4663 |
| Number of pages | 6 |
| Journal | Cancer Research |
| Volume | 55 |
| Issue number | 20 |
| Publication status | Published - 1995 |
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ASJC Scopus subject areas
- Cancer Research
- Oncology
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Mutational fingerprint induced by the antineoplastic drug chloroethyl-cyclohexyl-nitrosourea in mammalian cells. / Inga, Alberto; Iannone, Raffaella; Campomenosi, Paola; Molina, Francesco; Menichini, Paola; Abbondandolo, Angelo; Fronza, Gilberto.
In: Cancer Research, Vol. 55, No. 20, 1995, p. 4658-4663.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Mutational fingerprint induced by the antineoplastic drug chloroethyl-cyclohexyl-nitrosourea in mammalian cells
AU - Inga, Alberto
AU - Iannone, Raffaella
AU - Campomenosi, Paola
AU - Molina, Francesco
AU - Menichini, Paola
AU - Abbondandolo, Angelo
AU - Fronza, Gilberto
PY - 1995
Y1 - 1995
N2 - Using the pZ189 shuttle vector approach, we determined two chloroethylcyclohexyl-nitrosourea (CCNU)-induced mutation spectra (3 and 6 mM) in African green monkey kidney cells (CV1). One hundred and twenty-one independent clones (101 CCNU induced, 45 at 3 mM and 56 at 6 mM; 20 spontaneous) showing functional inactivation of the supF gene were analyzed. One hundred and five plasmids (91 CCNU induced, 41 at 3 mM and 50 at 6 mM; 14 spontaneous), showing no large deletion/rearrangements, were sequenced. Ninety mutants (81 CCNU induced and 9 spontaneous) showed at least one mutation in the supF region. The analysis of the 122 CCNU-induced mutations (56 and 66 at 3 and 6 mM, respectively) revealed that: (a) the majority of the mutations were GC-targeted base pair substitutions; (b) AT-targeted mutations were significantly more frequent in the CCNU-induced (6 mM) than in the spontaneous mutational spectrum (P <0.0006, Fisher's exact test); (c) mutational spectra obtained at 3 and 6 mM CCNU were significantly different (P <0.008); (d) induced mutations were nonrandomly located in both spectra and generated either a common hot spot (position 123, 5′-GGG-3′) or hot spots exclusive for each CCNU concentration (3 mM: position 159,5′-AGG-3′; 6 mM: position 109,5′-GGG-3′); (e) the occurrence of GC→ AT transitions was significantly different as a function of CCNU concentration (P <0.02, Fisher's exact test), the mutated G being almost exclusively preceded by a purine (5′Pu G) at 6 mM and by either Pu or Py at 3 mM; and (f) by applying Calladine's rules, we found that sequences encompassing the three CCNU hot spots shared identical helix parameters for no more than 2 bp steps 5′ (or 3 bp steps 3′) to the mutated G. Our results are consistent with the hypothesis that O6-alkylguanine is responsible, either directly or indirectly, for the majority of GC-targeted mutations, while O4-alkylthymine and/or N3-alkyladenine are probably responsible for AT-targeted mutations. The results suggest also that, in CV1 cells, the efficiency of the repair mechanism(s) involved in the removal of O6-alkylguanine is influenced by the DNA sequence context All of these factors determine the CCNU mutational fingerprint. CCNU has been implicated in the induction of therapy-related leukemias. The work presented here could be a valuable tool to verify this hypothesis at the molecular level by comparing the CCNU fingerprint with the p53 mutational spectrum obtained in patients formerly treated with CCNU and affected by a therapy-related leukemia.
AB - Using the pZ189 shuttle vector approach, we determined two chloroethylcyclohexyl-nitrosourea (CCNU)-induced mutation spectra (3 and 6 mM) in African green monkey kidney cells (CV1). One hundred and twenty-one independent clones (101 CCNU induced, 45 at 3 mM and 56 at 6 mM; 20 spontaneous) showing functional inactivation of the supF gene were analyzed. One hundred and five plasmids (91 CCNU induced, 41 at 3 mM and 50 at 6 mM; 14 spontaneous), showing no large deletion/rearrangements, were sequenced. Ninety mutants (81 CCNU induced and 9 spontaneous) showed at least one mutation in the supF region. The analysis of the 122 CCNU-induced mutations (56 and 66 at 3 and 6 mM, respectively) revealed that: (a) the majority of the mutations were GC-targeted base pair substitutions; (b) AT-targeted mutations were significantly more frequent in the CCNU-induced (6 mM) than in the spontaneous mutational spectrum (P <0.0006, Fisher's exact test); (c) mutational spectra obtained at 3 and 6 mM CCNU were significantly different (P <0.008); (d) induced mutations were nonrandomly located in both spectra and generated either a common hot spot (position 123, 5′-GGG-3′) or hot spots exclusive for each CCNU concentration (3 mM: position 159,5′-AGG-3′; 6 mM: position 109,5′-GGG-3′); (e) the occurrence of GC→ AT transitions was significantly different as a function of CCNU concentration (P <0.02, Fisher's exact test), the mutated G being almost exclusively preceded by a purine (5′Pu G) at 6 mM and by either Pu or Py at 3 mM; and (f) by applying Calladine's rules, we found that sequences encompassing the three CCNU hot spots shared identical helix parameters for no more than 2 bp steps 5′ (or 3 bp steps 3′) to the mutated G. Our results are consistent with the hypothesis that O6-alkylguanine is responsible, either directly or indirectly, for the majority of GC-targeted mutations, while O4-alkylthymine and/or N3-alkyladenine are probably responsible for AT-targeted mutations. The results suggest also that, in CV1 cells, the efficiency of the repair mechanism(s) involved in the removal of O6-alkylguanine is influenced by the DNA sequence context All of these factors determine the CCNU mutational fingerprint. CCNU has been implicated in the induction of therapy-related leukemias. The work presented here could be a valuable tool to verify this hypothesis at the molecular level by comparing the CCNU fingerprint with the p53 mutational spectrum obtained in patients formerly treated with CCNU and affected by a therapy-related leukemia.
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M3 - Article
C2 - 7553645
AN - SCOPUS:0028791837
VL - 55
SP - 4658
EP - 4663
JO - Journal of Cancer Research
JF - Journal of Cancer Research
SN - 0008-5472
IS - 20
ER -