These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Quercetin down-regulates signal transduction in human breast carcinoma cells.
    Author: Singhal RL, Yeh YA, Praja N, Olah E, Sledge GW, Weber G.
    Journal: Biochem Biophys Res Commun; 1995 Mar 08; 208(1):425-31. PubMed ID: 7887960.
    Abstract:
    Signal transduction activity was markedly elevated in cancer cells as shown by the increased activity of enzymes utilizing 1-phosphatidylinositol, PI (PI 4-kinase and PI-4-phosphate 5-kinase) for the production of the second messenger inositol 1,4,5-trisphosphate, IP3, in rat hepatomas (Cancer Res. 54: 2611;5574, 1994) and in human ovarian and breast carcinoma cells (Life Sci. 55:1487, 1994). Quercetin, a flavonoid, in human breast carcinoma MDA-MB-435 cells produced growth inhibition (IC50 = 55 microM) and cytotoxicity (LC50 = 26 microM). Quercetin inhibited PI kinase activity in extracts of breast carcinoma cells (IC50 = 6 microM) and in cultured cells (IC50 = 10 microM) with a minor inhibition of PIP kinase activity. IP3 concentration decreased in parallel with PI kinase activity. In time sequence studies quercetin in breast carcinoma cells brought down PI kinase and IP3 concentration in 60 min to 5 and 6%, respectively; PIP kinase activity was at 63% of controls. The results demonstrate for the first time in proliferating human breast carcinoma cells a reduction by quercetin of the increased capacity for signal transduction, thus providing a novel and sensitive target in cancer cells.
    [Abstract] [Full Text] [Related] [New Search]