AIM: To obtain the active human recombinant uridine diphosphate glucuronosyltransferase 1A3 (UGT1A3) enzyme from Chinese hamster lung (CHL) cells.METHODS: The full-length UGT1A3 gene was amplified by reverse transcrip...AIM: To obtain the active human recombinant uridine diphosphate glucuronosyltransferase 1A3 (UGT1A3) enzyme from Chinese hamster lung (CHL) cells.METHODS: The full-length UGT1A3 gene was amplified by reverse transcription-polymerase chain reaction (RT-PCR)using total RNA from human liver as template. The correct fragment confirmed by sequencing was subcloned into the mammalian expression vector pcDNA3.1 (+), and the recombinant vector was transfected into CHL cells using a calcium phosphate method. Expressed UGT1A3 protein was prepared from CHL cells resistant to neomycin (G418). Then the protein was added into a reaction mixture for glucuronidation of quercetin. The glucuronidation activity of UGT1A3 was determined by reverse phase-high performance liquid chromatography (RP-HPLC) coupled with a diode array detector (DAD). The quercetin glucuronide was confirmed by hydrolysis with β-glucuronidase. Control experiments were performed in parallel. The transcriptions of recombinants were also determined by RT-PCR.RESULTS: The gene was confirmed to be an allele (UGT1A3-3) of UGT1A3 by DNA sequencing. The fragment was introduced into pcDNA3.1 (+) successfully. Several colonies were obtained under the selection pressure of G418.The result of RT-PCR showed transcription of recombinants in mRNA level. Glucuronidation assay and HPLC analysis indicated UGT1A3 expressed heterologously in CHL cells was in an active form, and one of the gulcuronides corresponding to quercetin was also detected.CONCLUSION: Correct sequence of UGT1A3 gene can be obtained, and active UGT1A3 enzyme is expressed heterologously in CHL cells.展开更多
AIM:To investigate the association of variations in the cyclooxygenase-2 (COX2) and uridine diphosphate glucuronosyltransferase 1A6 (UGTIA6) genes and non-steroidal anti-inflammatory drugs (NSAIDs) use with ris...AIM:To investigate the association of variations in the cyclooxygenase-2 (COX2) and uridine diphosphate glucuronosyltransferase 1A6 (UGTIA6) genes and non-steroidal anti-inflammatory drugs (NSAIDs) use with risk of colon cancer.METHODS: NSAIDs, which are known to reduce the risk of colon cancer, act directly on COX2 and reduce its activity. Epidemiological studies have associated variations in the COX2 gene with colon cancer risk, but others were unable to replicate this finding. Similarly,enzymes in the UGT1A6 gene have been demonstrated to modify the therapeutic effect of NSAIDs on colon adenomas. Polymorphisms in the UGTIA6 gene have been statistically shown to interact with NSAID intake to influence risk of developing colon adenomas, but not colon cancer. Here we examined the association of tagging single nucleotide polymorphisms (SNPs) in the COX2 and UGTIA6 genes, and their interaction with NSAID consumption, on risk of colon cancer in a population of 422 colon cancer cases and 481 population controls.RESULTS: No SNP in either gene was individually statistically significantly associated with colon cancer, nor did they statistically significantly change the protective effect of NSAID consumption in our sample. Like others, we were unable to replicate the association of variants in the COX2 gene with colon cancer risk (P 〉 0.05),and we did not observe that these variants modify the protective effect of NSAIDs (P 〉 0.05). We were able to confirm the lack of association of variants in UGT1A6 with colon cancer risk, although further studies will have to be conducted to confirm the association of these variants with colon adenomas.CONCLUSION: Our study does not support a role of COX2 and UGTIA6 genetic variations in the development of colon cancer.展开更多
基金Supported by the National Natural Science Foundation of China,No. C30100232to Xin Li,No.C30225047to Su Zeng,and the Zhejiang Provincial Natural Science Foundation,No.C300487to Xin Li
文摘AIM: To obtain the active human recombinant uridine diphosphate glucuronosyltransferase 1A3 (UGT1A3) enzyme from Chinese hamster lung (CHL) cells.METHODS: The full-length UGT1A3 gene was amplified by reverse transcription-polymerase chain reaction (RT-PCR)using total RNA from human liver as template. The correct fragment confirmed by sequencing was subcloned into the mammalian expression vector pcDNA3.1 (+), and the recombinant vector was transfected into CHL cells using a calcium phosphate method. Expressed UGT1A3 protein was prepared from CHL cells resistant to neomycin (G418). Then the protein was added into a reaction mixture for glucuronidation of quercetin. The glucuronidation activity of UGT1A3 was determined by reverse phase-high performance liquid chromatography (RP-HPLC) coupled with a diode array detector (DAD). The quercetin glucuronide was confirmed by hydrolysis with β-glucuronidase. Control experiments were performed in parallel. The transcriptions of recombinants were also determined by RT-PCR.RESULTS: The gene was confirmed to be an allele (UGT1A3-3) of UGT1A3 by DNA sequencing. The fragment was introduced into pcDNA3.1 (+) successfully. Several colonies were obtained under the selection pressure of G418.The result of RT-PCR showed transcription of recombinants in mRNA level. Glucuronidation assay and HPLC analysis indicated UGT1A3 expressed heterologously in CHL cells was in an active form, and one of the gulcuronides corresponding to quercetin was also detected.CONCLUSION: Correct sequence of UGT1A3 gene can be obtained, and active UGT1A3 enzyme is expressed heterologously in CHL cells.
基金Supported by A Damon Runyon Cancer Research Foundation Clinical Investigator Award,CI-8An R25 training grant from the National Cancer Institute,R25T CA094186+1 种基金The Case Center for Transdisciplinary Research on Energetics and Cancer,1U54 CA-116867-01A National Cancer Institute K22 Award,1K22 CA120545-01
文摘AIM:To investigate the association of variations in the cyclooxygenase-2 (COX2) and uridine diphosphate glucuronosyltransferase 1A6 (UGTIA6) genes and non-steroidal anti-inflammatory drugs (NSAIDs) use with risk of colon cancer.METHODS: NSAIDs, which are known to reduce the risk of colon cancer, act directly on COX2 and reduce its activity. Epidemiological studies have associated variations in the COX2 gene with colon cancer risk, but others were unable to replicate this finding. Similarly,enzymes in the UGT1A6 gene have been demonstrated to modify the therapeutic effect of NSAIDs on colon adenomas. Polymorphisms in the UGTIA6 gene have been statistically shown to interact with NSAID intake to influence risk of developing colon adenomas, but not colon cancer. Here we examined the association of tagging single nucleotide polymorphisms (SNPs) in the COX2 and UGTIA6 genes, and their interaction with NSAID consumption, on risk of colon cancer in a population of 422 colon cancer cases and 481 population controls.RESULTS: No SNP in either gene was individually statistically significantly associated with colon cancer, nor did they statistically significantly change the protective effect of NSAID consumption in our sample. Like others, we were unable to replicate the association of variants in the COX2 gene with colon cancer risk (P 〉 0.05),and we did not observe that these variants modify the protective effect of NSAIDs (P 〉 0.05). We were able to confirm the lack of association of variants in UGT1A6 with colon cancer risk, although further studies will have to be conducted to confirm the association of these variants with colon adenomas.CONCLUSION: Our study does not support a role of COX2 and UGTIA6 genetic variations in the development of colon cancer.