Skip to main content
main-content

01.12.2014 | Original Paper | Ausgabe 6/2014

Cellular Oncology 6/2014

E4BP4 is a repressor of epigenetically regulated SOSTDC1 expression in breast cancer cells

Zeitschrift:
Cellular Oncology > Ausgabe 6/2014
Autoren:
Akhilesh Rawat, Gopal Gopisetty, Rajkumar Thangarajan

Abstract

Purpose

We and others show that SOSTDC1 is down-regulated in breast cancer tissues compared to matched normal tissues. Previously, we found that epigenetic mechanisms underlie the down-regulation of SOSTDC1 in gastric cancer cells. The aim of this study was to assess the putative epigenetic regulation of SOSTDC1 expression in breast cancer cells.

Methods

Microarray-based expression profiling was performed in a series of primary breast cancers and matched normal tissues. Real-time PCR was performed to assess SOSTDC1 and E4BP4 mRNA levels in MCF7, BT549, MBMDA231, T47D (breast cancer) and HEK293T (normal kidney) cell lines. Methylation-specific PCR (MSP) and bisulfite sequencing PCR (BSP) were performed to assess the methylation level of the SOSTDC1 gene promoter, and 5-Aza 2-deoxycytidine (5'-Aza-dC) treatment was used to induce its demethylation. A luciferase assay was used to measure SOSTDC1 promoter activity in vitro. Stable shRNA-mediated knockdown of E4BP4 was carried out in MCF7 cells and confirmed by Western blotting. Finally, MCF7 cell proliferation and survival were measured by MTS assay.

Results

We found that SOSTDC1 is frequently down-regulated in primary breast cancers (98.2 %) and in all breast cancer cell lines tested. MSP and BSP analyses revealed SOSTC1 promoter hypermethylation at CpG sites. 5'-Aza-dC treatment induced a striking down-regulation of SOSTDC1 gene expression, whereas BSP analysis showed demethylation of its promoter. Subsequent in silico SOSTDC1 promoter analysis indicated the presence of putative transcriptional repressor E4BP4 binding sites, and promoter deletion studies indeed revealed repressor binding regions encompassing these E4BP4 binding sites. Relative quantification of E4BP4 expression showed an inverse correlation to SOSTDC1 expression in the breast cancer cell lines tested. Exogenous over-expression of E4BP4 in HEK-293 and BT549 cells reduced SOSTDC1 expression and its promoter activity, respectively. Stable shRNA-mediated E4BP4 BT549 and MCF7 knock-down cells treated with 5'-Aza-dC exhibited up-regulation of SOSTDC1 expression and a concomitant inhibition of cell proliferation and survival.

Conclusion

From our results we conclude that the transcriptional repressor E4BP4 plays a role in repressing epigenetically regulated SOSTDC1 expression in breast cancer cells, which can be reverted by E4BP4 silencing.

Bitte loggen Sie sich ein, um Zugang zu diesem Inhalt zu erhalten

★ PREMIUM-INHALT
e.Med Interdisziplinär

Für Ihren Erfolg in Klinik und Praxis - Die beste Hilfe in Ihrem Arbeitsalltag als Mediziner

Mit e.Med Interdisziplinär erhalten Sie Zugang zu allen CME-Fortbildungen und Fachzeitschriften auf SpringerMedizin.de.

Jetzt e.Med zum Sonderpreis bestellen!

Weitere Produktempfehlungen anzeigen
Literatur
Über diesen Artikel

Weitere Artikel der Ausgabe 6/2014

Cellular Oncology 6/2014 Zur Ausgabe
  1. Sie können e.Med Innere Medizin 14 Tage kostenlos testen (keine Print-Zeitschrift enthalten). Der Test läuft automatisch und formlos aus. Es kann nur einmal getestet werden.

  2. Sie können e.Med Onkologie 14 Tage kostenlos testen (keine Print-Zeitschrift enthalten). Der Test läuft automatisch und formlos aus. Es kann nur einmal getestet werden.

Neu im Fachgebiet Pathologie

01.10.2020 | Magenkarzinom | Schwerpunkt: In-situ-Hybridisierung | Ausgabe 6/2020

ISH-basierte HER2-Diagnostik

30.09.2020 | Schwerpunkt: In-situ-Hybridisierung | Ausgabe 6/2020

RNA-in-situ-Hybridisierung: Technologie, Möglichkeiten und Anwendungsbereiche

28.09.2020 | Lungenkarzinome | Schwerpunkt: In-situ-Hybridisierung | Ausgabe 6/2020

Anwendungen der FISH in der Diagnostik von Lungenkarzinomen