Susceptibility To Lung Cancer In Relation To Cyp1A1 And GSTM1 Genetic Polymorphisms And Tar Of Cigarettes

1. Polymorphisms of CYPlAl genes Msp I in the Mongolian nationality and Han nationality population of Inner MongoliaThe polymorphisms of CYP1Al genes Msp I were determined by PCR-RFLP in 80 unrelated subjects of the Mongolian nationality and 120 unrelated subjects of Han nationality. The genotype frequency distributions of CYPlAl genotypes of wild-type, heterozygote, homozygous variant in Mongolian nationality population and Han nationality population were 35.0% 48.7% 16.3% and 33.3% 52.5% 14.2% respectivily. Chi-square tests showed that there was no significant difference between the two groups. The mathematics test showed that Mongolian nationality squares with the law of Hardy-Weinberg of genetic equilibrium but Han nationality deviates from the law of Hardy-Weinberg of genetic equilibrium a little. The coincidental test showed that both Mongolian and Han nationalitysquare with the law of Hardy-Weinberg of genetic equilibrium. The genotype frequency distributions of CYPlAl gene of both groups did not exhibit obvious difference.2. Susceptibility to lung cancer in relation to CYPlAl and GSTM1 genetic polymorphisms in population of Inner MongoliaCYPlAl and GSTM1 genetic polymorphisms were determined by PCR-RFLP in 63 lung cancer cases and healthy controls respectively. The frequencies of CYPlAl variation type (vt/vt) and GSTMl(-) were 36.5% , 65.1% and 19.1% , 47.6% in lung cancer cases and healthy controls respectively. Statistical tests showed significant difference between the two groups. Combined analysis of the polymorphisms showed that CYP1Al (vt/vt)/ GSTMl(-) and CYPlAl(vtM) / GSTM1(+) were 28.6% and 7.9% respectively among the lung cancer patients who were tested. Statistical tests showed significant difference between the two groups. Pearson Chi-Square of sex differential showed that there was no significance between the homozygous variation genotype of CYPlAl / GSTMl(-) and the other genotypes of CYPlAl / GSTMl(-). Statistical tests showed that susceptibility to lung cancer was related to smoking. There may be a synergetic interaction between CYPlAl variation type (vt/vt) and smoking on the elevated susceptibility to lung cancer, butGSTMl(-) and smoking may not. The polymorphisms of CYPlAl variation type (vt/vt) and GSTMl(-) were the risk factors of lung cancer of Inner Mongolia. There may be a synergetic interaction between CYPlAl variation type (vt/vt) and GSTMl(-) on the elevated susceptibility to lung cancer, So is the CYPlAl variation type (vt/vt) and smoking. Smoking may also relate to the susceptibility to lung cancer.3. Influence of tar of cigarettes on the expression of aromatic hydrocarbon receptor genes and CYPlAl genes of mice lungsTo study the influence of tar of cigarettes on the expression of AHR genes and CYPlAl genes of mice lungs and their time and dose-response relationships, the mice were injected by intra-abdominally with 1%LD5O (5.29mg/kg), 2%LD50 (10.58mg/kg) and 3%LD50 (15.87mg/kg) cigarettes tar for 24, 48 and 72 hours once a day respectively. Total RNA of mice lungs extracted was purified by RNA kit. RT-PCR technique was used to determine AHR and CYPlAl genetic expression. The expression of AHR and CYPlAl genes of mice lungs at different doses of tar of cigarettes and at different times were analyzed with P -actin as control. AHR genetic expression increased after 72 hours treated with 1%LD5O cigarettes tar. AHR and CYPlAl genes increased after 48 and 72 hours treated with 2%LD50 and 3%LD50 cigarettes tar.Tar of cigarettes could regulate up AHR and CYP1A1 genes at some doses and some times. The effects of up-regulation showed time and dose-dependent relationship. The regulations of expression of AHR genes were earlier than CYP1 Al genes and with low doses.4. Influence of tar of cigarettes and passive smoking on the activity of aromatic hydrocarbon hydryoxylase and glutathion S-transferase of mice lungsThe Influence of tar of cigarettes and passive smoking on the activity of aromatic hydrocarbon hydryoxylase (AHH) and glutathion S-transferase(GST) of mice lungs and their time and dose-response relationship were studied. The mice were intra-abdominally with 1%LD5O (5.29mg/kgX2%LD50( 10.58mg/kg)and 3%LD50( 15.87mg/kg)cigarettes tar for 24, 48 and 72 hours once a day respectively. The control groups were injected intra-abdominally with 0.5% tween-80 normal saline once a day. Then the activity of AHH and GST were tested. Passive smoking group was put in the box of 50L. The level of smog was maintained 69.41 g/m3 for 30 minute two times a day. Control group was not smoking but at the same condition. Then the activity of AHH and GST were tested. The activity of AHH increased after 72 hours treatment with 2%LD50 cigarettes tar and with 3%LD50 cigarettes tar for 48 hours, 72hours . The activity ofAHH of mice lungs treated with tar of cigarettes of 2%LD50 and 3%LD50 was different 48 hours and 72 hours later. The statistical tests showed significant difference. The effects of up-regulation showed dose-dependent and time-dependent relationship. The activity of AHH of mice lungs was also increased by passive smoking. There were no significant difference of GST activity between the treatment of three kinds of concentration of cigarettes tar and control, so was the passive smoking.