Involvement of PKA and Sp1 in the induction of p27Kip1 by tamoxifen

Lee, Te-Hsiu; Chang, Hsuan; Chuang, Li‐Yeh; Hung, Wen‐Chun

doi:10.1016/s0006-2952(03)00258-2

Cited by 20 publications

(14 citation statements)

References 31 publications

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“…Phosphorylation occurs within multiple motifs of the Sp1 molecule, such as the C-terminus, and often results in functional changes, for example, the capability of DNA binding and/or gene-promoter activation. Phosphorylation of Sp1 plays an important role in modulating its transcriptional regulation of multiple genes [45,46]. In the present study, we demonstrated that ERK1/2-dependent phosphorylation of Sp1 was important for induction of fascin expression in ESCC cells.…”

Section: Discussionsupporting

confidence: 60%

Specificity protein 1 regulates fascin expression in esophageal squamous cell carcinoma as the result of the epidermal growth factor/extracellular signal-regulated kinase signaling pathway activation

et al. 2010

Cell. Mol. Life Sci.

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The overexpression of fascin in human carcinomas is associated with aggressive clinical phenotypes and poor prognosis. However, the molecular mechanism underlying the increased expression of fascin in cancer cells is largely unknown. Here, we identified a Sp1 binding element located at -70 to -60 nts of the FSCN1 promoter and validated that Sp1 specifically bound to this element in esophageal carcinoma cells. Fascin expression was enhanced by Sp1 overexpression and blocked by Sp1 RNAi knockdown. Specific inhibition of ERK1/2 decreased phosphorylation levels of Sp1, and thus suppressed the transcription of the FSCN1, resulting in the down-regulation of fascin. Stimulation with EGF could enhance fascin expression via activating the ERK1/2 pathway and increasing phosphorylation levels of Sp1. These data suggest that FSCN1 transcription may be subjected to the regulation of the EGF/EGFR signaling pathway and can be used as a viable biomarker to predict the efficacy of EGFR inhibitors in cancer therapies.

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Section: Discussionsupporting

confidence: 60%

Specificity protein 1 regulates fascin expression in esophageal squamous cell carcinoma as the result of the epidermal growth factor/extracellular signal-regulated kinase signaling pathway activation

et al. 2010

Cell. Mol. Life Sci.

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“…5D). Previous studies have shown that GC-rich sites in the p27 promoter mediate induction of p27 by vitamin D3 and tamoxifen in human myelomonocytic U937 and H358 lung cancer cells (53,54), and up-regulation of p27 involves cooperative interactions of Sp1 and other factors. In contrast, our results show that siRNA for Sp1 has minimal effects on p27 expression or luciferase activity in Panc-1 cell-transfected constructs containing p27 promoter inserts.…”

Section: Discussionmentioning

confidence: 99%

Role of Sp Proteins in Regulation of Vascular Endothelial Growth Factor Expression and Proliferation of Pancreatic Cancer Cells

Smith²,

et al. 2004

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Sp proteins play an important role in angiogenesis and growth of cancer cells, and specificity protein 1 (Sp1) has been linked to vascular endothelial growth factor (VEGF) expression in pancreatic cancer cells. RNA interference was used to investigate the role of Sp family proteins on regulation of VEGF expression and proliferation of Panc-1 pancreatic cancer cells. Using a series of constructs containing VEGF promoter inserts, it was initially shown that Sp1 and Sp3 were required for transactivation, and this was primarily dependent on proximal GC-rich motifs. We also showed that Sp4 was expressed in Panc-1 cells, and RNA interference assays suggested that Sp4 cooperatively interacted with Sp1 and Sp3 to activate VEGF promoter constructs in these cells. However, the relative contributions of Sp proteins to VEGF expression were variable among different pancreatic cancer cell lines. Small inhibitory RNAs for Sp3, but not Sp1 or Sp4, inhibited phosphorylation of retinoblastoma protein, blocked G 0 /G 1 3 S-phase progression, and up-regulated p27 protein/promoter activity of Panc-1 cells; similar results were observed in other pancreatic cancer cells, suggesting that Sp3-dependent growth of pancreatic cancer cells is caused by inhibition of p27 expression.

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“…(66,72), which is also a corepressor for the estrogen receptor, the androgen receptor, and the PR (72). The proximal Sp1 sites of the p27 promoter are required for the response to vitamin D 3 (33) and tamoxifen (41). Furthermore, the Sp1-binding sites have a common important role in the modulation of the cell cycle (53).…”

Section: Discussionmentioning

confidence: 99%

TReP-132 Is a Novel Progesterone Receptor Coactivator Required for the Inhibition of Breast Cancer Cell Growth and Enhancement of Differentiation by Progesterone

Gizard

Robillard

Gross

et al. 2006

Molecular and Cellular Biology

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The sex steroid progesterone is essential for the proliferation and differentiation of the mammary gland epithelium during pregnancy. In relation to this, in vitro studies using breast carcinoma T47D cells have demonstrated a biphasic progesterone response, consisting of an initial proliferative burst followed by a sustained growth arrest. However, the transcriptional factors acting with the progesterone receptor (PR) to mediate the progesterone effects on mammary cell growth and differentiation remain to be determined. The steroid hormones estrogen and progesterone play key roles in the growth of the mammary gland (49). Estrogens appear to be the main drive for proliferation of the mammary gland epithelium, whereas progesterone is required for its terminal growth and differentiation (27). The induction of mammary epithelial development during pregnancy is mediated by a rise in progesterone levels (51). The physiological effects of progesterone occur mainly via interaction with specific intracellular progesterone receptors (PRs), PR-A and PR-B, which are products of a single gene and members of the nuclear receptor (NR) family (11). Studies performed on mice in which the expression of both PRs was ablated have demonstrated that progesterone is necessary for ductal branching and the lobulo-alveolar development of the mammary gland (45). More recently, selective ablation of each receptor isoform has indicated that PR-B is specifically required for the progesterone-dependent development of the mammary gland during pregnancy (11).In relation to the function of progesterone in breast development, both growth-stimulatory and -inhibitory effects have been previously reported on breast epithelium cells and cancer development in tumor animal models (11,42,46). Moreover, in vitro studies using the PR-positive mammary carcinoma T47D cell line as a model have demonstrated a biphasic cellular response to either progesterone or its derivatives (R5020 or ORG 2058), with an immediate proliferative burst followed by a sustained growth arrest (28,38,50). As with many hormones and growth factors, the regulation of retinoblastoma gene product (pRB) phosphorylation-a critical checkpoint of the G 1 /S transition-plays a major role in the control of proliferation by progesterone (18,39,71). The initial pRB phosphorylation provoked by progesterone is catalyzed by constitutively expressed cyclin-dependent kinases (CDKs), which are activated through interaction with specific cyclins induced by progesterone (39). The ensuing growth arrest is associated, at least in part, with the transitory induction of the cyclin-dependent kinase inhibitors (CDKIs) p21Cip1/WAF1 (p21) and p18 INK4c(p18), followed by a sustained induction of p27 Kip1 (p27) (28,

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Involvement of PKA and Sp1 in the induction of p27Kip1 by tamoxifen

Cited by 20 publications

References 31 publications

Specificity protein 1 regulates fascin expression in esophageal squamous cell carcinoma as the result of the epidermal growth factor/extracellular signal-regulated kinase signaling pathway activation

Specificity protein 1 regulates fascin expression in esophageal squamous cell carcinoma as the result of the epidermal growth factor/extracellular signal-regulated kinase signaling pathway activation

Role of Sp Proteins in Regulation of Vascular Endothelial Growth Factor Expression and Proliferation of Pancreatic Cancer Cells

TReP-132 Is a Novel Progesterone Receptor Coactivator Required for the Inhibition of Breast Cancer Cell Growth and Enhancement of Differentiation by Progesterone

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