63. Study on the deletions of the FHIT gene mRNA in murine lung cancer induced by Coal Tar Pitch

癌变畸变突变001年10月第13卷第4期Carcinogenesis, Teratogenesis and Mutagenesis Vol 13 No 4 Oct., 2001ZHANG Qiao, YANG Shengli, SONG Aiyun', GONG Ya-ou2, ZHANG. Tanmu31. Department of Occupational Health and Toxicology, Henan Medical University, Zhengzhou 450052. 2. Department of Esophageal cancer Research Henan Medical University, Zhengzhou 450052. 3. Department ofPharmaceutical chemistry, Henan Medical institute Zhengzhou 450052Oridonin( Orid is an efficacious component of antitumour extracted from Chinese Herb Rabdisia rubeseasHemsl. )Hara. It was used to treat the tumour of digestive tract on the clinic. To investigate the mechanism ofhe antitumour of Orid, We used different methods to detect its antimutagenicity. Ames test: Salmonella typhimurium strains contained TA97, TA98, TA100 and TA102 were used. The test was without S-9. It was donethat the observation of the inhibition of Orid on reverse mutation induced by different mutagens in the test. @2Micronucleus assay of polychromatic erythocytes( PCe ) in mice bone marrow. The assay was set up negativecontrol group(0.9% NaCl, 20 ul/mice ) positive control group( cyclophosphamide, CP, 20 mg/kg) and testgroups( CP+ Orid ) The test groups contained three concentration of Orid 20 mg/kg, 10 mg/kg, 5 mg/kg)uNscheduled DNA synthesis( UDS ) assay in the primary cells of the lung and liver of rat. There were threegroups in the assay. They were negative control group( DMSo, 1%), positive control group( 10- mol/L HN2HCI for the liver cells 10-7mol/L 3-MC for the lung cells )and test groups( positive control added 10-5mg/nl, 10-4mg/ml and 10- mg/ml Orid respectively ) The results indicated: Orid could evidently inhibit thereverse mutation on Salmonella typhimurium strains TA98 and TA100. The rate of maximum inhibition were 891% and 80.2% respectively. @Orid could significantly reduce micronucleus frequencies induced by CP( P<0.01 ) Orid could inhibit UDS induced by the mutagens in the primary cells of the lung and liver of rat.Theinhibition on UDS induced by NHi HCl in the primary cell of liver was particularly obvious(P<0.01),andThe above results suggested that Orid has significant antimutagenic activity and it may correlate with theantitumour effect of orio文献标识码:A文章编号:004-616X2001)4-0246-01a63. Study on the deletions of the fhit gene mRNA in murine lung cancer induced by Coal Tar PitchWu Yiming Zhou Xiaoshan, Wu Yongjun, Ba Yue Xu DongDepartment of Labor Health and Toxicology School of Public Heath, Zhengzhou University Zhengzhou 450052Abstract: Epidemiological studies have shown that people who were exposed to Coal Tar Pitch( CTP had ahigher incidence of lung cancer than control population. In addition CTP could induce two kinds of lung cancerin rats and mice. Although CTP is widely considered as a definite carcinogen the mechanism of carcinogenesisstill unknown. Ohta discovered a new gene-Fhit( Fragile histidine triad by exon- capture technique in 1996It was reported that this gene was closely associated with the environmental carcinogen. FHIt gene is a focus forthe study of environmental carcinogen acted upon. In our experiment CtP was heated directly to produce fumean environment sI中国煤化工 f ctP to indmodel of lung cancer. Through series killing the deletion ofCNMHGnesis was studied. Thepurpose of this study is to investigate whether the molecular genetic event can be used to detect primary lung cancer. It can also provide useful information to infer the Fhit changes in human lung tumor genesisMethods and materials 64 Kunming mice were provided by Henan Laboratory Animal Center. They were 4癌变畸变突变200年10月第13卷第4期Carcinogenesis, Teratogenesis and Mutagenesis Vol 13 No 4 Oct., 2001eeks old and half were male. All the mice were randomly divided into experimental and control groups. Eachgroup had 32 mice. Experimental material was Coal tar pitch which was producedjing Certain Steel Faxperimental mice were put into 50 liter sealed vessel which the fume was blown into by circulating system the CTP was heated by electric hot plate at 400C until CtP did not produce fume. During experimentalperiod mouse s diet habit and activities were recorded. The mice in experimental group were exposed to CTPfume for 12 weeks then half of the mice were executed after stopping inhale CTp fume the rest were executedin 24th weeks. The wet weight of lung and liver were measured. The specimen of lung was divided into twoarts. One part was fixed by 10% formalin. The other was frozen in liquid nitrogen. The murine cDNA se-quence was found in Gen Bank. The primers were devised by Primer Devising software. The targeted DNA fragment was amplified by nested-PCR. The expected length of product was 694bpResults: The diet habit and activities of mice in experimental group were normal the weights of the micethe experimental groups were 32.83+5.40 gram and 38.34+5.47 gram in 12th weeks and 24th weeks respetively. There were significant loss compared to the control group mice. The index of lung and body in experimenal group was increased significantly compared to control group. @2 The main histology type of lung cancer induced by CTP fume was carcinoid(87.5%). In experimental group, there were 2 cases of carcinoid occurred(2/16)in 12th week whereas there were 5 cases and I case of adenocarcinoma occurred in 24th weeks. However, there was no any cancer occurred in control group. 3 Deletions of FHIT transcripts were found in the tissue of precancerous lesion tumor lesion and its adjacent tissues. Nested-PCR results show that 52% PCR products exhibited aberrant bands in there group. Among 8 mice with tumors aberrant bands were shown in4 carcinoids mice 5 of 7 precancerous specimens showed aberrant bands. Except for the wild-type 694bp bandthere were one or two aberrant bands which were shorter than normal band. The length of deletions was 100bpor so. Aberrant transcriptions were not detected in control groupConclusions: The main histological type of lung cancer induced by CTP was carcinoid. This finding indicatesthat the CtP fume can specifically cause mouse carcinoid. @2 Aberrant FHIT transcripts were detected consistently from precancerous lesion to tumor specimen, which suggests that abnormality of FHIt gene transcript is anly and frequent molecular genetic event and this change can last to the occurrence of tumor. The finding isvaluable for early diagnosisKey words: coal tar pitch fume FHIT gene i nested-PCR文献标识码:A文章编号:1004-616X(2001)4-0246-01b中国煤化工CNMHG247