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Analysis of p53 and K-ras mutational patterns in lung cancer
Abstracts
Amplitkatton lung
of C-myc,
C-Ha-ras
I Lung
and C-sis Oncogenes
Cancer
in human
cancer
He Liig.
Zhan De-jin. Chen Jia-kun. Wu Zhong-hang
Institute for Chemical Guangzhou, China
Carcinogenesis,
Guangzhou
and Du Ying-xiu. Medical
14 Suppl.
I (1996)
S235-S245
and c-myc are common molecular events of lung cancers induced by burning coal smoke and provide further evidence that burning coal is a risk factor for lung cancer.
College.
Gene amplification and protooncogene activation have been found to be associated with the development of many NmOrs. To study the pathogenesis of lung cancer, we analyzed the amplification of C-myc, CHams and C-sis oncogenes in human lung cancer tissues. Oligonucleotide probes made from plasmids pV-SIS, pHSR-l(C-myc) and pBC-Nl(C-Hams) were labelled with P’* dCTP. The amplification of C-myc, C-Ha-ras and C-sis oncogenes in 32 lung cancer tissue samples and 6 “non lung cancer tissue” samples (2 normal tissues, 2 lung abscess tissues and 2 tracheobmnchial ectasy lungs) were analyzed using the Southern hybridization technique. The results showed mat in squamous cell carcinoma (SCC, n= 17) adenocarcinoma (AC, n=3) and small cell carcinoma (ScC, n=6) the amplification of Hams was obtained in 59, 33. and 33% of the tissues, respectively; for C-myc amplification was obtained in 23, 33 and 16% of the cases, respectively and for C-sis the percentages were 23, 11 and 17, respectively. In “non lung cancer tissues” there was no amplification in the six tissues examined. One of 3 oncogens were positive in 14/17 cases of SCC, 6/9 cases for AC and 4/6 cases for ScC respectively; while 2 of 3 oncogens were positive in 4/17, 119 and O/6 cases for SCC, AC and ScC respectively. The combination of 2 oncogens present were C-Hams + C-myc, C-Hams + C-cis and C-myc + C-sis. These results suggest that the amplification of these three oncogenes, particularly C-myc and C-sis, is associated with the development of human lung cancer. The amplification of the C-Hams gene may play an important mle in the pathogenesis of squamous cell carcinoma.
Expression of p53 and c-myc in mouse lung cancer induced by coal burning Lin Chun-yan, Dai Xudong, Song Lan-ying, Shi Yu-bo and Sun Xiwen. Heilongjiang Cancer Research Institute, Harbin. China Previous epidemiological studies have reported an association between coal burning and human lung cancer. To confirm the relationship between coal burning and lung cancer initiation and progression, the expression of ~53 and c-myc in mouse lung cancer induced by burning coal smoke was shldied by in situ hybridization techniques (ISH). A total of 240 mice were divided into four groups and were exposed to different amounts of burning coal (160. 105 and 6Og, and controls) for sixty minutes/day for two years. The lung cancers induced were all adenocarcinomas. The incidence of lung cancer was 9/37 (24.3 46) in the “16Ogcoal” group, 6147 (12.8%) in the “105g-coal” group, 5/53 (9.4%) in the “6Ogcoal” group, and 2152 (3.6%) in the control group. Thirteen samples with obvious characteristics of cancer in adjacent tissues were taken from the experimental (exposed to burning coal smoke) groups. Five lung tissue samples were obtained from the controls. The tissues were fixed with formalin and processed in paraffin wax. All samples were analyzed for the expression of c-myc and ~53 by ISH, using a biotin-labeled probe. The tissue sections were digested with proteinase K. The presence of DNA-RNA hybrids was demonstrated using an alkaline phosphatase streptavidin conjugate nitroblue tetrazolium (NBT) detection system. There was an over-expression of ~53 mRNA in all 13 lung cancer samples and in 5 of die adjacent tissue samples. Similarly, c-myc was found to be over-expressed in 9 lung cancer samples and in I adjacent tissue sample. On the other hand, no expression of ~53 and c-myc in control samples was detected. Thus, a significant difference in the expression of c-myc gene (P = 0.002) and ~53 gene (P = 0.001) was found between me experimental groups (exposed to burning coal smoke) and the controls. The data confirm that over-expression of ~53
Point mutation at codon 11 and 12 of Ha-ras and Ki-ras oncogenes in human fetal epitheltal cells treated with benzo(a)pyrene tram-7,8dtol-anti-9,10-epoxtde Zhan De-jin, Chen Jia-kun, Jin Bo, Yi Fei and Wu Zhong-liang. Institute for Chemical China
Carcinogenesis.
Gunngzhou
Medical
College,
Guangzhou,
Six samples of human fetal tracheal epimelium (HFTE) cultured in vitro were exposed for 2-6 weeks to tram-7,8dihydroxy-anti-9,10-epoxy7,8,9.10-tetrahydrobenzo[a]pyrene Hl(a)PDE], an oxidative metabolite of benzo(a)pyrene [B(a)P]. The point mutations at codons 11 (GCC) and 12 (GGC) of Hams, codon 11 (GCT) and 12 (GGT) of Ki-ras oncogenes in these HFTE tissue samples were detected by polymerase chain reaction combined with restriction fragment length polymorphism analysis and direct DNA sequencing. The primary results showed that all of these six HFTE samples treated wirh B(a)PDE exhibited point mutations at codons 11 and 12 of the Hams gene. Among them, one was GGC+GTC at codon 12. one was CCGMTGG at codons 11 and 12, one was CCGG+CTTG at codons 11 and 12. one was CCGG+CTGT at codons 11 and 12, and one was CCGG+CTGG and CCAG at codons 11 and 12. Only one HATE sample had point mutations at codon 12 of the Ki-ras gene (GGT+GAT). These six HFTE samples did not exhibit any transformed characteristics in cellular morphology. The proportions of B(a)PDE- induced base pair substitution in human fetal tracheal epithelium, which occurred in DNA sequence 5’-CCGG-3’ of the Hams gene, were higher than those in the DNA sequence 5’CTGG-3’ of the Ki-ras gene, with the predominant mutation being the G+A transition. This suggests that point mutation and activation of Hams or Ki-ras oncogenes may occur before the cells display transfotmed phenotypes. The mutational sensitivities to B(a)PDE appear to be related to the sequence of DNA.
Analysis of p53 and K-ras mutational patterns tn lung cancer Gao Hong-guang’, Chen Jia-kun”, Wu Zhong-liangb, Whong Wen-zong” and Ong Tong-mad. ‘Division of Respiratory Disease Studies, National Institute Krginia, Medical
for Occupational Safety and USA “Institute for Chemical College, Guangzhou. China
Health, Morgantown, West Carcinogenesis, Guangeou
Lung cancer is die most prevalent cancer in the world. The mechanism of lung carcinogenesis is not really known. Studies were conducted to examine die mutational spectra of Ki-ras exons l-2 and ~53 exons 5-8 in lung cancer tissues from 27 Chinese patients (10 smokers and 17 nonsmokers) using single strand conformational polymorphism (SSCP) and DNA sequencing. The results show that Ki-ras mutations were present in 11 of 13 (84.6%) squamous cell carcinomas and in 4 of 12 (33.3%) adenocarcinomas. All of the mutations were concentrated in exon 1 and distributed among codons 12-32. In ~53, mutations were present in 10 of 13 (76.9%) squamous cell carcinomas and in 7 of 12 (58.3%) adenocarcinomas, and were most frequent at codons 275 and 281. Most of the cancer tissues were found to contain multiple mutations in the ~53 gene. The mutational spectra in ~53 did not appear to be significantly different between smokers and nonsmokers and consisted of AT+TA transversions (64%) and GC+AT transitions (32.0%). Based on the exons studied, the number of mutations in these two genes was significantly higher in squamous cell carcinomas than in adenocarcinomas. These results, in part, indicate that cigarette smoking may cause and/or be associated with a specific mutational pattern in the I&ras proto-oncogene.
Amplitkatton lung
of C-myc,
C-Ha-ras
I Lung
and C-sis Oncogenes
Cancer
in human
cancer
He Liig.
Zhan De-jin. Chen Jia-kun. Wu Zhong-hang
Institute for Chemical Guangzhou, China
Carcinogenesis,
Guangzhou
and Du Ying-xiu. Medical
14 Suppl.
I (1996)
S235-S245
and c-myc are common molecular events of lung cancers induced by burning coal smoke and provide further evidence that burning coal is a risk factor for lung cancer.
College.
Gene amplification and protooncogene activation have been found to be associated with the development of many NmOrs. To study the pathogenesis of lung cancer, we analyzed the amplification of C-myc, CHams and C-sis oncogenes in human lung cancer tissues. Oligonucleotide probes made from plasmids pV-SIS, pHSR-l(C-myc) and pBC-Nl(C-Hams) were labelled with P’* dCTP. The amplification of C-myc, C-Ha-ras and C-sis oncogenes in 32 lung cancer tissue samples and 6 “non lung cancer tissue” samples (2 normal tissues, 2 lung abscess tissues and 2 tracheobmnchial ectasy lungs) were analyzed using the Southern hybridization technique. The results showed mat in squamous cell carcinoma (SCC, n= 17) adenocarcinoma (AC, n=3) and small cell carcinoma (ScC, n=6) the amplification of Hams was obtained in 59, 33. and 33% of the tissues, respectively; for C-myc amplification was obtained in 23, 33 and 16% of the cases, respectively and for C-sis the percentages were 23, 11 and 17, respectively. In “non lung cancer tissues” there was no amplification in the six tissues examined. One of 3 oncogens were positive in 14/17 cases of SCC, 6/9 cases for AC and 4/6 cases for ScC respectively; while 2 of 3 oncogens were positive in 4/17, 119 and O/6 cases for SCC, AC and ScC respectively. The combination of 2 oncogens present were C-Hams + C-myc, C-Hams + C-cis and C-myc + C-sis. These results suggest that the amplification of these three oncogenes, particularly C-myc and C-sis, is associated with the development of human lung cancer. The amplification of the C-Hams gene may play an important mle in the pathogenesis of squamous cell carcinoma.
Expression of p53 and c-myc in mouse lung cancer induced by coal burning Lin Chun-yan, Dai Xudong, Song Lan-ying, Shi Yu-bo and Sun Xiwen. Heilongjiang Cancer Research Institute, Harbin. China Previous epidemiological studies have reported an association between coal burning and human lung cancer. To confirm the relationship between coal burning and lung cancer initiation and progression, the expression of ~53 and c-myc in mouse lung cancer induced by burning coal smoke was shldied by in situ hybridization techniques (ISH). A total of 240 mice were divided into four groups and were exposed to different amounts of burning coal (160. 105 and 6Og, and controls) for sixty minutes/day for two years. The lung cancers induced were all adenocarcinomas. The incidence of lung cancer was 9/37 (24.3 46) in the “16Ogcoal” group, 6147 (12.8%) in the “105g-coal” group, 5/53 (9.4%) in the “6Ogcoal” group, and 2152 (3.6%) in the control group. Thirteen samples with obvious characteristics of cancer in adjacent tissues were taken from the experimental (exposed to burning coal smoke) groups. Five lung tissue samples were obtained from the controls. The tissues were fixed with formalin and processed in paraffin wax. All samples were analyzed for the expression of c-myc and ~53 by ISH, using a biotin-labeled probe. The tissue sections were digested with proteinase K. The presence of DNA-RNA hybrids was demonstrated using an alkaline phosphatase streptavidin conjugate nitroblue tetrazolium (NBT) detection system. There was an over-expression of ~53 mRNA in all 13 lung cancer samples and in 5 of die adjacent tissue samples. Similarly, c-myc was found to be over-expressed in 9 lung cancer samples and in I adjacent tissue sample. On the other hand, no expression of ~53 and c-myc in control samples was detected. Thus, a significant difference in the expression of c-myc gene (P = 0.002) and ~53 gene (P = 0.001) was found between me experimental groups (exposed to burning coal smoke) and the controls. The data confirm that over-expression of ~53
Point mutation at codon 11 and 12 of Ha-ras and Ki-ras oncogenes in human fetal epitheltal cells treated with benzo(a)pyrene tram-7,8dtol-anti-9,10-epoxtde Zhan De-jin, Chen Jia-kun, Jin Bo, Yi Fei and Wu Zhong-liang. Institute for Chemical China
Carcinogenesis.
Gunngzhou
Medical
College,
Guangzhou,
Six samples of human fetal tracheal epimelium (HFTE) cultured in vitro were exposed for 2-6 weeks to tram-7,8dihydroxy-anti-9,10-epoxy7,8,9.10-tetrahydrobenzo[a]pyrene Hl(a)PDE], an oxidative metabolite of benzo(a)pyrene [B(a)P]. The point mutations at codons 11 (GCC) and 12 (GGC) of Hams, codon 11 (GCT) and 12 (GGT) of Ki-ras oncogenes in these HFTE tissue samples were detected by polymerase chain reaction combined with restriction fragment length polymorphism analysis and direct DNA sequencing. The primary results showed that all of these six HFTE samples treated wirh B(a)PDE exhibited point mutations at codons 11 and 12 of the Hams gene. Among them, one was GGC+GTC at codon 12. one was CCGMTGG at codons 11 and 12, one was CCGG+CTTG at codons 11 and 12. one was CCGG+CTGT at codons 11 and 12, and one was CCGG+CTGG and CCAG at codons 11 and 12. Only one HATE sample had point mutations at codon 12 of the Ki-ras gene (GGT+GAT). These six HFTE samples did not exhibit any transformed characteristics in cellular morphology. The proportions of B(a)PDE- induced base pair substitution in human fetal tracheal epithelium, which occurred in DNA sequence 5’-CCGG-3’ of the Hams gene, were higher than those in the DNA sequence 5’CTGG-3’ of the Ki-ras gene, with the predominant mutation being the G+A transition. This suggests that point mutation and activation of Hams or Ki-ras oncogenes may occur before the cells display transfotmed phenotypes. The mutational sensitivities to B(a)PDE appear to be related to the sequence of DNA.
Analysis of p53 and K-ras mutational patterns tn lung cancer Gao Hong-guang’, Chen Jia-kun”, Wu Zhong-liangb, Whong Wen-zong” and Ong Tong-mad. ‘Division of Respiratory Disease Studies, National Institute Krginia, Medical
for Occupational Safety and USA “Institute for Chemical College, Guangzhou. China
Health, Morgantown, West Carcinogenesis, Guangeou
Lung cancer is die most prevalent cancer in the world. The mechanism of lung carcinogenesis is not really known. Studies were conducted to examine die mutational spectra of Ki-ras exons l-2 and ~53 exons 5-8 in lung cancer tissues from 27 Chinese patients (10 smokers and 17 nonsmokers) using single strand conformational polymorphism (SSCP) and DNA sequencing. The results show that Ki-ras mutations were present in 11 of 13 (84.6%) squamous cell carcinomas and in 4 of 12 (33.3%) adenocarcinomas. All of the mutations were concentrated in exon 1 and distributed among codons 12-32. In ~53, mutations were present in 10 of 13 (76.9%) squamous cell carcinomas and in 7 of 12 (58.3%) adenocarcinomas, and were most frequent at codons 275 and 281. Most of the cancer tissues were found to contain multiple mutations in the ~53 gene. The mutational spectra in ~53 did not appear to be significantly different between smokers and nonsmokers and consisted of AT+TA transversions (64%) and GC+AT transitions (32.0%). Based on the exons studied, the number of mutations in these two genes was significantly higher in squamous cell carcinomas than in adenocarcinomas. These results, in part, indicate that cigarette smoking may cause and/or be associated with a specific mutational pattern in the I&ras proto-oncogene.