HOMEPRODUCTSCOMPANYCONTACTFAQResearchDictionaryPharmaSign Up FREE or Login

Implication of protein tyrosine phosphatase 1B in MCF-7 cell proliferation and resistance to 4-OH tamoxifen.

Abstract
The protein tyrosine phosphatase 1B (PTP1B) and the T-cell protein tyrosine phosphatase (TC-PTP) were initially thought to be mainly anti-oncogenic. However, overexpression of PTP1B and TC-PTP has been observed in human tumors, and recent studies have demonstrated that PTP1B contributes to the appearance of breast tumors by modulating ERK pathway. In the present work, we observed that decreasing the expression of TC-PTP or PTP1B in MCF-7 cells using siRNA reduced cell proliferation without affecting cell death. This reduction in proliferation was associated with decreased ERK phosphorylation. Moreover, selection of tamoxifen-resistant MCF-7 cells, by long-term culture in presence of 4-OH tamoxifen, resulted in cells that display overexpression of PTP1B and TC-PTP, and concomitant increase in ERK and STAT3 phosphorylation. siRNA experiments showed that PTP1B, but not TC-PTP, is necessary for resistance to 4-OH tamoxifen. Therefore, our work indicates that PTP1B could be a relevant therapeutic target for treatment of tamoxifen-resistant breast cancers.
AuthorsChristophe Blanquart, Salah-Eddine Karouri, Tarik Issad
JournalBiochemical and biophysical research communications (Biochem Biophys Res Commun) Vol. 387 Issue 4 Pg. 748-53 (Oct 02 2009) ISSN: 1090-2104 [Electronic] United States
PMID19635455 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
Chemical References
  • Antineoplastic Agents, Hormonal
  • RNA, Small Interfering
  • Tamoxifen
  • Protein Tyrosine Phosphatase, Non-Receptor Type 1
Topics
  • Antineoplastic Agents, Hormonal (pharmacology)
  • Breast Neoplasms (enzymology)
  • Cell Line, Tumor
  • Cell Proliferation (drug effects)
  • Drug Resistance, Neoplasm (genetics)
  • Female
  • Humans
  • Protein Tyrosine Phosphatase, Non-Receptor Type 1 (genetics, metabolism)
  • RNA, Small Interfering (genetics)
  • Tamoxifen (pharmacology)

Join CureHunter, for free Research Interface BASIC access!

Take advantage of free CureHunter research engine access to explore the best drug and treatment options for any disease. Find out why thousands of doctors, pharma researchers and patient activists around the world use CureHunter every day.
Realize the full power of the drug-disease research graph!


Choose Username:
Email:
Password:
Verify Password:
Enter Code Shown: