Identification of a Novel Cis Element Required for Cell Density-dependent Down-regulation of Insulin-like Growth Factor-2 P3 Promoter Activity in CaCo2 Cells

Dai, Bosong; Wu, Haoming; Holthuizen, Elly; Singh, Pomila

doi:10.1074/jbc.m007789200

Cited by 8 publications

(23 citation statements)

References 35 publications

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“…The wells were washed and incubated with anti-p65 NF-nB antibody (1:1,000 dilution) for 1 h and washed thrice again followed by incubation with horseradish peroxidase-conjugated second antibody (1:10,000; 50 AL) for 1 h. The wells were washed four times followed by the addition of the chemiluminescent working solution. The resulting chemiluminescence, proportional to the levels of nuclear p65 NF-nB, bound to the consensus sequence, was measured with a luminometer (Dinex Technologies) by our published methods (23).…”

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confidence: 99%

Antiapoptotic Effects of Progastrin on Pancreatic Cancer Cells Are Mediated by Sustained Activation of Nuclear Factor-κB

Rengifo-Cam¹,

Umar

Sarkar³

et al. 2007

Cancer Research

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Progastrin (PG) exerts proliferative and antiapoptotic effects on intestinal epithelial and colon cancer cells via Annexin II (ANX-II). In here, we show that ANX-II similarly mediates proliferative and antiapoptotic effects of PG on a pancreatic cancer cell line, AR42J. The role of several signaling molecules was examined in delineating the biological activity of PG. PG (0.1-1.0 nmol/L) caused a significant increase (2-to 5-fold) in the phosphorylation of phosphatidylinositol 3-kinase (PI3K) , and p65 nuclear factor-KB (NF-KB; Ser 536 ). Inhibition of p44/42 ERKs (PD98059), p38 MAPK (SB203580), Akt, and PI3K (LY294002), individually or combined, partially reversed antiapoptotic effects of PG. The kinetics of phosphorylation of IKKA/B in response to PG matched the kinetics of phosphorylation and degradation of IKBA and correlated with phosphorylation, nuclear translocation, and activation of p65 NF-KB. NF-KB essential modulator-binding domain peptide (an inhibitor of IKKA/B) effectively blocked the activity of p65 NF-KB in response to PG. Activation of p65 NF-KB, in response to PG, was 70% to 80% dependent on phosphorylation of MAPK/ERK and PI3K/Akt molecules. Down-regulation of p65 NF-KB by specific small interfering RNA resulted in the loss of antiapoptotic effects of PG on AR42J cells. These studies show for the first time that the canonical pathway of activation of p65 NF-KB mediates antiapoptotic effects of PG. Therefore, targeting PG and/or p65 NF-KB may be useful for treating cancers, which are dependent on autocrine or circulating PGs for their growth. [Cancer Res 2007;67(15):7266-74]

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confidence: 99%

Antiapoptotic Effects of Progastrin on Pancreatic Cancer Cells Are Mediated by Sustained Activation of Nuclear Factor-κB

Rengifo-Cam¹,

Umar

Sarkar³

et al. 2007

Cancer Research

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“…Indeed, the Igf2 gene can be divided into three main areas that provide different mRNA molecules displaying different expression levels. The first area is encompassing the region of the promoters, the second area is containing the common exons (4,5,6) and the third area is the 3' region that contains the polyA tail signal ( Figure 6). (equivalent to P2 and P3 in mice) contributed significantly to the total number of copies of Igf2, meaning that they were most strongly expressed in correlates with other promoters.…”

Section: Discussionmentioning

confidence: 99%

“…The expression of the Insulin-Like Growth Factor 2 (Igf2) gene is quite complex because it is carried out by several promoters and only on the paternally inherited allele. The expression level of the different promoters is completely different depending on the tissue and the mouse strain [4,5,19]. In mammals, embryonic growth and development are controlled by a number of genes, among them is Igf2.…”

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confidence: 99%

Igf2 Gene Expression Levels in Wild-Type and Mutant Mice

Tran¹,

Tran²,

Thanh³

et al. 2017

OSJ

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Genomic imprinting occurs where only one allele of a gene is expressed depending on its parental origin. The imprinted Igf2 gene (Insulin-like growth factor 2) is encoding a growth factor, which play an important role in embryonic development and formation of the placenta. The regulation and expression of Igf2 is carried out by different promoters. Promoter expression is extremely complex in wild-type mice during development and is altered in several mutant mice bearing deletions at the Igf2/H19 locus. In this work, we analyzed the Igf2 RNA expression of the placenta-specific P0 promoter in placental tissue (embryonic day 17) of both wild-type and mutant mice. For all the other promoters, we used RNA extracted from liver tissues (postnatal day 7.5). All these RNAs were reverse transcribed to cDNA before quantifying expression levels of the promoters by quantitative PCR (qPCR).Our results show that transcriptions of Igf2 P2 and P3 promoters are the highest in all mice analyzed, except in ΔU2/Dom mutant mice where P0 and P1 promoters were highly expressed, while they display low expression in all the other mice strains analyzed. Furthermore, all promoters were stably expressed at high levels in wild-type and ΔU2/Dom mutation, but at a low level in Δ3/Dom

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“…Exponentially growing cells were seeded at 2 Â 10 5 cells per 35 mm cell culture dishes, and cultured in growth medium (DMEM supplemented with 2 mM glutamine, 1 mM sodium pyruvate and 25 mM high glucose, and 10% heat-inactivated FBS) as described previously (Singh et al, 1994a(Singh et al, , b, 1996Dai et al, 2001) …”

Section: Cell Culturementioning

confidence: 99%

“…Luc and b-gal activities were measured in the cell lysates as previously described (Dai et al, 1997;Dai et al, 2001).…”

Section: Luc and B-gal Activity Assaysmentioning

confidence: 99%

Identification of a novel SP3 binding site in the promoter of human IGFBP4 gene: role of SP3 and AP-1 in regulating promoter activity in CaCo2 cells

Shen

Singh

2004

Oncogene

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Insulin-like growth factor binding protein 4 (IGFBP4/ BP4) gene expression plays an important role in the transition from proliferation to differentiation of a human colon cancer cell line, CaCo2. We recently cloned and identified multiple cis elements (including putative binding sites for activator protein 1 (AP-1) and specificity proteins (Sps) ) in the promoter of human BP4 gene, and measured a significant upregulation of the promoter activity in response to c-Jun. We therefore examined the role of the single AP-1 site (À869/À863) and other cis elements, in regulating the expression of hBP4 gene, in the current studies. Deletion of a 25 bp sequence from À872 to À848, which contains the AP-1 site, significantly reduced BP4 promoter activity by approximately 50%. Surprisingly, mutation of the AP-1 site did not produce significant alteration in the activity of the BP4 promoter. However, mutation of 7 bp (5 0 -TGCTGCA) at the 3 0 end of the AP-1 site resulted in significantly decreasing the promoter activity by 450%. Proteins bound to the 25 bp probe (À872/À848) could be supershifted by antibodies specific for JunD and Sp3 in an EMSA. JunD binding was abolished on mutation of the AP-1 site and Sp3 binding was abolished on mutation of the 7 bp at À861/À855; binding of the purified Sp3 protein to the 25 bp probe was similarly abolished on mutation of the newly discovered Sp3 binding site (TGCTGCA). BP4 promoter activity was upregulated in insect cells in response to Sp3 expression, confirming a functional importance of the novel Sp3 binding site. These studies suggest that the Sp3 binding site, rather than the AP-1 site, may be playing a significant role in regulating the expression of IGFBP4 gene in CaCo2 cells.

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Identification of a Novel Cis Element Required for Cell Density-dependent Down-regulation of Insulin-like Growth Factor-2 P3 Promoter Activity in CaCo2 Cells

Cited by 8 publications

References 35 publications

Antiapoptotic Effects of Progastrin on Pancreatic Cancer Cells Are Mediated by Sustained Activation of Nuclear Factor-κB

Antiapoptotic Effects of Progastrin on Pancreatic Cancer Cells Are Mediated by Sustained Activation of Nuclear Factor-κB

Igf2 Gene Expression Levels in Wild-Type and Mutant Mice

Identification of a novel SP3 binding site in the promoter of human IGFBP4 gene: role of SP3 and AP-1 in regulating promoter activity in CaCo2 cells

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