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Reversion of transcriptional repression of Sp1 by 5 aza-2' deoxycytidine restores TGF-beta type II receptor expression in the pancreatic cancer cell line MIA PaCa-2.
Cancer Res 2001; 61(16):6239-47CR

Abstract

The pancreatic cancer cell line, MIA PaCa-2 is not responsive to transforming growth factor beta (TGF-beta) because of a lack of expression of the TGF-beta type II receptor (RII). We show that the lack of RII expression is caused by a deficit of the transcription factor Sp1. Nuclear run-off assays and Western immunoblot showed low levels of transcription and protein levels of Sp1, respectively. Treatment of MIA PaCa-2 cells with the DNA methyl transferase inhibitor, 5-aza-2'-deoxycytidine, resulted in an increase in the rate of Sp1 transcription, in Sp1 protein expression, and in the binding of Sp1 to the RII promoter. Ectopic expression of Sp1 cDNA in MIA PaCa-2 cells led to an increase in RII promoter-chloramphenicol acetyltransferase activity and RII expression. Expression of Sp1 cDNA also caused a reduction in both growth and clonogenicity that was associated with restoration of responsiveness to TGF-beta. Conversely, cells that express RII (BxPC-3 and MIA PaCa-2 Sp1 transfectants) when treated with mithramycin, an inhibitor of Sp1 binding, showed a reduction in RII mRNA expression. The reduction of RII mRNA was attributed to a decrease in RII promoter-chloramphenicol acetyltransferase activity that was associated with a decrease in Sp1 binding to the RII promoter. These data indicate that transcriptional repression of the Sp1 gene in MIA PaCa-2 cells plays a role in the transcriptional inactivation of the RII gene and thus lack of responsiveness to TGF-beta.

Authors+Show Affiliations

Department of Surgery, University of Texas Health Science Center, San Antonio, Texas 78229-3900, USA.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

11507078

Citation

Venkatasubbarao, K, et al. "Reversion of Transcriptional Repression of Sp1 By 5 Aza-2' Deoxycytidine Restores TGF-beta Type II Receptor Expression in the Pancreatic Cancer Cell Line MIA PaCa-2." Cancer Research, vol. 61, no. 16, 2001, pp. 6239-47.
Venkatasubbarao K, Ammanamanchi S, Brattain MG, et al. Reversion of transcriptional repression of Sp1 by 5 aza-2' deoxycytidine restores TGF-beta type II receptor expression in the pancreatic cancer cell line MIA PaCa-2. Cancer Res. 2001;61(16):6239-47.
Venkatasubbarao, K., Ammanamanchi, S., Brattain, M. G., Mimari, D., & Freeman, J. W. (2001). Reversion of transcriptional repression of Sp1 by 5 aza-2' deoxycytidine restores TGF-beta type II receptor expression in the pancreatic cancer cell line MIA PaCa-2. Cancer Research, 61(16), pp. 6239-47.
Venkatasubbarao K, et al. Reversion of Transcriptional Repression of Sp1 By 5 Aza-2' Deoxycytidine Restores TGF-beta Type II Receptor Expression in the Pancreatic Cancer Cell Line MIA PaCa-2. Cancer Res. 2001 Aug 15;61(16):6239-47. PubMed PMID: 11507078.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Reversion of transcriptional repression of Sp1 by 5 aza-2' deoxycytidine restores TGF-beta type II receptor expression in the pancreatic cancer cell line MIA PaCa-2. AU - Venkatasubbarao,K, AU - Ammanamanchi,S, AU - Brattain,M G, AU - Mimari,D, AU - Freeman,J W, PY - 2001/8/17/pubmed PY - 2001/9/8/medline PY - 2001/8/17/entrez SP - 6239 EP - 47 JF - Cancer research JO - Cancer Res. VL - 61 IS - 16 N2 - The pancreatic cancer cell line, MIA PaCa-2 is not responsive to transforming growth factor beta (TGF-beta) because of a lack of expression of the TGF-beta type II receptor (RII). We show that the lack of RII expression is caused by a deficit of the transcription factor Sp1. Nuclear run-off assays and Western immunoblot showed low levels of transcription and protein levels of Sp1, respectively. Treatment of MIA PaCa-2 cells with the DNA methyl transferase inhibitor, 5-aza-2'-deoxycytidine, resulted in an increase in the rate of Sp1 transcription, in Sp1 protein expression, and in the binding of Sp1 to the RII promoter. Ectopic expression of Sp1 cDNA in MIA PaCa-2 cells led to an increase in RII promoter-chloramphenicol acetyltransferase activity and RII expression. Expression of Sp1 cDNA also caused a reduction in both growth and clonogenicity that was associated with restoration of responsiveness to TGF-beta. Conversely, cells that express RII (BxPC-3 and MIA PaCa-2 Sp1 transfectants) when treated with mithramycin, an inhibitor of Sp1 binding, showed a reduction in RII mRNA expression. The reduction of RII mRNA was attributed to a decrease in RII promoter-chloramphenicol acetyltransferase activity that was associated with a decrease in Sp1 binding to the RII promoter. These data indicate that transcriptional repression of the Sp1 gene in MIA PaCa-2 cells plays a role in the transcriptional inactivation of the RII gene and thus lack of responsiveness to TGF-beta. SN - 0008-5472 UR - https://www.unboundmedicine.com/medline/citation/11507078/Reversion_of_transcriptional_repression_of_Sp1_by_5_aza_2'_deoxycytidine_restores_TGF_beta_type_II_receptor_expression_in_the_pancreatic_cancer_cell_line_MIA_PaCa_2_ L2 - http://cancerres.aacrjournals.org/cgi/pmidlookup?view=long&pmid=11507078 DB - PRIME DP - Unbound Medicine ER -