TY - JOUR
T1 - The role of Sp1 and Sp3 in the constitutive DPYD gene expression
AU - Zhang, Xue
AU - Li, Lin
AU - Fourie, Jeanne
AU - Davie, James R.
AU - Guarcello, Vincenzo
AU - Diasio, Robert B.
N1 - Funding Information:
We thank Dr. Martin R. Johnson for critically reading the manuscript. This work was supported by CA62164. We would also like to acknowledge CIHR grant MOP-15183 (to JRD).
PY - 2006/5
Y1 - 2006/5
N2 - Dihydropyrimidine dehydrogenase (DPD), the initial and rate-limiting enzyme in the 5-fluorouracil (5-FU) catabolic pathway, has been implicated as one of the factors determining the efficacy and toxicity of the anticancer agent 5-FU. Studies have attributed variation in DPD activity partially to alterations at the transcriptional level of DPYD gene. We investigated the transcription factors implicated in the constitutive expression of DPYD by utilizing a 174-bp fragment of the DPYD promoter region in which three consensus Sp protein binding sites (SpA, SpB and SpC) were predicted. The binding of Sp1 and Sp3 transcription factors to this region was detected by electrophoretic mobility shift and chromatin immunoprecipitation assays. By ectopically expressing human Sp1 and Sp3 in Sp-deficient Drosophila S2 cells, we demonstrated that Sp1 is a strong activator, while Sp3 by its own is a weak activator of the DPYD promoter. Moreover, Sp3 may serve as a competitor of Sp1, thus decreasing the Sp1 induced promoter activity. SpA, SpB and SpC sites are all Sp1 inducible. In the full activation of the DPYD promoter in human cell lines, the SpB site is essential; the SpC site works cooperatively with SpB, while SpA has minor promoter activity. These studies provide further insight into the molecular mechanisms underlying the heterogeneity of DPD activity, and may facilitate the efficacy and safety of 5-FU-based chemotherapy.
AB - Dihydropyrimidine dehydrogenase (DPD), the initial and rate-limiting enzyme in the 5-fluorouracil (5-FU) catabolic pathway, has been implicated as one of the factors determining the efficacy and toxicity of the anticancer agent 5-FU. Studies have attributed variation in DPD activity partially to alterations at the transcriptional level of DPYD gene. We investigated the transcription factors implicated in the constitutive expression of DPYD by utilizing a 174-bp fragment of the DPYD promoter region in which three consensus Sp protein binding sites (SpA, SpB and SpC) were predicted. The binding of Sp1 and Sp3 transcription factors to this region was detected by electrophoretic mobility shift and chromatin immunoprecipitation assays. By ectopically expressing human Sp1 and Sp3 in Sp-deficient Drosophila S2 cells, we demonstrated that Sp1 is a strong activator, while Sp3 by its own is a weak activator of the DPYD promoter. Moreover, Sp3 may serve as a competitor of Sp1, thus decreasing the Sp1 induced promoter activity. SpA, SpB and SpC sites are all Sp1 inducible. In the full activation of the DPYD promoter in human cell lines, the SpB site is essential; the SpC site works cooperatively with SpB, while SpA has minor promoter activity. These studies provide further insight into the molecular mechanisms underlying the heterogeneity of DPD activity, and may facilitate the efficacy and safety of 5-FU-based chemotherapy.
KW - DPYD
KW - Dihydropyrimidine dehydrogenase
KW - Promoter
KW - Sp1
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U2 - 10.1016/j.bbaexp.2006.05.001
DO - 10.1016/j.bbaexp.2006.05.001
M3 - Article
C2 - 16806531
AN - SCOPUS:33745886277
SN - 0167-4781
VL - 1759
SP - 247
EP - 256
JO - Biochimica et Biophysica Acta - Gene Structure and Expression
JF - Biochimica et Biophysica Acta - Gene Structure and Expression
IS - 5
ER -