In order to study the altered molecular events during laryngeal carcinogenesis and elucidate the role of Haras oncogene amplification and mutation. we have examined their profile by polymerase chain reaction (PCR) and...In order to study the altered molecular events during laryngeal carcinogenesis and elucidate the role of Haras oncogene amplification and mutation. we have examined their profile by polymerase chain reaction (PCR) and selective oligonucleotide hybridization. We analyzed the mutational status of codon 12 of Haras in 22 laryngeal carcinomas and 10 normal tissues. and found that 7 of 22 laryngeal carcinomas contained a Ha-ras mutation at codon 12. The frequency of mutation was 32%. None of the normal tissues revealed mutation. Moreover. no amplification was found in cancers when compared to the normal. Ourfindings indicated that the activated Ha-ras gene existed in laryngeal carcinoma. and activation of the Haras gene by mutation at codon 12 might play a key role in laryngeal carcinogenesis.展开更多
The effects of two antisense oligodeoxynucleotides on the expression of c-Ha-ras proto-oncogene and the growth of human gastric carcinoma cell lines were observed. Synthetic 15-mer directed at the region of the transl...The effects of two antisense oligodeoxynucleotides on the expression of c-Ha-ras proto-oncogene and the growth of human gastric carcinoma cell lines were observed. Synthetic 15-mer directed at the region of the translational initiation site of c-Ha-ras proto-oncogene (ASO-r) greatly inhibited the proliferation (55. 61%,P<0. 05) and DNA synthesis (76. 79%,P<0. 05) of MGc-803 cell line. It also inhibited the proliferation (62. 02%,P<0. 05) and DNA synthesis (76. 78%, P<0. 05) of SGc-7901 cell line. A reduction in intracellular P21 ras protein levels in MGc-803 cell line was observed 6 h after the treatment with ASO-r and maintained over 12 h. Another synthetic 15-mer targeted against the initiation codon and downstream 4 codons of c-myc proto-oncogene (ASOm) inhibited only DNA synthesis of MGc-803 cell line (71. 37%, P<0. 05). The control 15-mer did not inhibit the expression of P21 protein and proliferation of these cell lines. These experiments seemed to provide evidence that ASO-r could be effective in inhibiting the expression of c-Ha-ras proto-oncogene and controlling the growth of human gastric carcinoma cells,and that the over-expression of c-Ha-ras proto-oncogene might mainly be associated with the malignant proliferation of human gastric carcinoma cells.展开更多
A 2.0 kb fragment DNA plasmid which expresses antisense to the upstream first exon of c-Ha-ras oncogene was transfected into Ha-ras transformed cell lines, GCM-3T3 and REF-4.3. The transfection leads to the inhibition...A 2.0 kb fragment DNA plasmid which expresses antisense to the upstream first exon of c-Ha-ras oncogene was transfected into Ha-ras transformed cell lines, GCM-3T3 and REF-4.3. The transfection leads to the inhibition of malignant behaviour, shown by decreasing of growth speed, colony forming ability on soft agar, tumorigenicity in nude mice and increasing ot differentiation degree. In GCM-3T3 cells the lung metastasis frequency became much less (from 60% to 12.5%) after the transfection and the expression of ras oncogene product, and p21 protein was obviously decreased in the transfected cells. This work has first shown the inhibitory effect of antisense RNA on neoplastic behaviour in China.展开更多
ve To study the presence of c-Ha-ras oncogene mutations in hydatidiform mole (HM) tissues and to further explore its relationship with mole's malignancy
文摘In order to study the altered molecular events during laryngeal carcinogenesis and elucidate the role of Haras oncogene amplification and mutation. we have examined their profile by polymerase chain reaction (PCR) and selective oligonucleotide hybridization. We analyzed the mutational status of codon 12 of Haras in 22 laryngeal carcinomas and 10 normal tissues. and found that 7 of 22 laryngeal carcinomas contained a Ha-ras mutation at codon 12. The frequency of mutation was 32%. None of the normal tissues revealed mutation. Moreover. no amplification was found in cancers when compared to the normal. Ourfindings indicated that the activated Ha-ras gene existed in laryngeal carcinoma. and activation of the Haras gene by mutation at codon 12 might play a key role in laryngeal carcinogenesis.
文摘The effects of two antisense oligodeoxynucleotides on the expression of c-Ha-ras proto-oncogene and the growth of human gastric carcinoma cell lines were observed. Synthetic 15-mer directed at the region of the translational initiation site of c-Ha-ras proto-oncogene (ASO-r) greatly inhibited the proliferation (55. 61%,P<0. 05) and DNA synthesis (76. 79%,P<0. 05) of MGc-803 cell line. It also inhibited the proliferation (62. 02%,P<0. 05) and DNA synthesis (76. 78%, P<0. 05) of SGc-7901 cell line. A reduction in intracellular P21 ras protein levels in MGc-803 cell line was observed 6 h after the treatment with ASO-r and maintained over 12 h. Another synthetic 15-mer targeted against the initiation codon and downstream 4 codons of c-myc proto-oncogene (ASOm) inhibited only DNA synthesis of MGc-803 cell line (71. 37%, P<0. 05). The control 15-mer did not inhibit the expression of P21 protein and proliferation of these cell lines. These experiments seemed to provide evidence that ASO-r could be effective in inhibiting the expression of c-Ha-ras proto-oncogene and controlling the growth of human gastric carcinoma cells,and that the over-expression of c-Ha-ras proto-oncogene might mainly be associated with the malignant proliferation of human gastric carcinoma cells.
文摘A 2.0 kb fragment DNA plasmid which expresses antisense to the upstream first exon of c-Ha-ras oncogene was transfected into Ha-ras transformed cell lines, GCM-3T3 and REF-4.3. The transfection leads to the inhibition of malignant behaviour, shown by decreasing of growth speed, colony forming ability on soft agar, tumorigenicity in nude mice and increasing ot differentiation degree. In GCM-3T3 cells the lung metastasis frequency became much less (from 60% to 12.5%) after the transfection and the expression of ras oncogene product, and p21 protein was obviously decreased in the transfected cells. This work has first shown the inhibitory effect of antisense RNA on neoplastic behaviour in China.
基金This work was supported by the Bureau of Health of Guangdong Province (No. B1999139)
文摘ve To study the presence of c-Ha-ras oncogene mutations in hydatidiform mole (HM) tissues and to further explore its relationship with mole's malignancy
