We have employed Chinese hamster ovary (CHO) cells containing a human chromosome 11 (termed AL hybrid cells) as a highly sensitive detection system for mutagenesis in an effort to evaluate possible direct mutagenic effects of cigarette smoke condensate (CSC) and its fractions. Cytotoxicity induced by Nmethyl-N'-nitro-N-Nitrosoguanidine (MNNG) in AL cells increased with time of incubation. The 50% inhibitory concentration of MNNG after 1, 3, 6 and 20 hr of incubation was 0.8, 0.4, 0.2 and 0.1 micromoles, respectively. Mutagenicity increased with dose and time reaching a maximum of 1,250 mutants/100,000 survivors (800% above background) after 3 hr of incubation with 2 micromolar MNNG and a maximum of 1,700 mutants/100,000 survivors (1,100 % above background) after 20 hr of incubation with 0.2 micromolar MNNG. The cytotoxicity of CSC increased with increasing incubation time with 50% inhibitory concentrations of 100, 80, 50 and 30 micrograms/ml after 1, 3, 6 and 20 hr of incubation, respectively. CSC mutagenicity increased with time of incubation up to 3 hr with a maximum of 300 mutants/100,000 survivors (250% above control) after incubation with 100 micrograms/ml CSC (p value less than 0.0005, Student's t-test). Cytotoxicity and mutagenicity of CSC were inversely proportional to cell density, while cytotoxicity and mutagenicity of MNNG were unaffected by cell density. The 3 hr incubation time and 50% inhibitory concentration of the acidic fraction of CSC (30 micrograms/ml) induced 350 mutants/100,000 survivors (a 230% increase above background, p value less than 0.0005). The basic and neutral fractions caused a much lower increase at the 50% inhibitory concentration (80 and 200 micrograms/ml, respectively). The possible role of oxy-radicals generated by tobacco smoke condensate and its fractions in mutagenesis of AL hybrid cells is being investigated.

Agency
National Institute of Health (NIH)
Institute
Division of Cancer Epidemiology And Genetics (NCI)
Type
Intramural Research (Z01)
Project #
1Z01CP005542-03
Application #
3896370
Study Section
Project Start
Project End
Budget Start
Budget End
Support Year
3
Fiscal Year
1989
Total Cost
Indirect Cost
Name
Cancer Epidemiology and Genetics
Department
Type
DUNS #
City
State
Country
United States
Zip Code