Aqueous extract of Arbutus unedo inhibits STAT1 activation in human breast cancer cell line MDA-MB-231 and human fibroblasts through SHP2 activation.
Arbutus unedo L. has been for a long time employed in traditional and popular medicine as an astringent, diuretic, urinary anti-septic, and more recently, in the therapy of hypertension and diabetes. Signal transducer and activator of transcription 1 (STAT1) is a fascinating and complex protein with multiple yet contrasting transcriptional functions. Although activation of this nuclear factor is finely regulated in order to control the entire inflammatory process, its hyper-activation or time-spatially erroneous activation may lead to exacerbation of inflammation. The modulation of this nuclear factor, therefore, has recently been considered as a new strategy in the treatment of inflammatory diseases. In this study, we present data showing that the aqueous extract of Arbutus unedo's leaves exerts inhibitory action on interferon-gamma (IFN-gamma) elicited activation of STAT1, both in human breast cancer cell line MDA-MB-231 and in human fibroblasts. This down-regulation of STAT1 is shown to result from a reduced tyrosine phosphorylation of STAT1 protein. Evidence is also presented indicating that the inhibitory effect of this extract may be mediated through enhancement of tyrosine phosphorylation of SHP2 tyrosine phosphatase. The modulation of this nuclear factor turns out into the regulation of the expression of a number of genes involved in the inflammatory response such as inducible nitric oxide synthase (iNOS) and intercellular adhesion molecule-1 (ICAM-1). Taken together, our results suggest that the employment of the Arbutus unedo aqueous extract is promising, at least, as an auxiliary anti-inflammatory treatment of diseases in which STAT1 plays a critical role.
Mariotto
S
S
Dipartimento di Scienze Morfologico-Biomediche, Sezione di Chimica Biologica, Università degli Studi di Verona. Strada Le Grazie, 8, 37134,Verona, Italy. hisanori.suzuki@univr.it.
Ciampa
A R
AR
de Prati
A Carcereri
AC
Darra
E
E
Vincenzi
S
S
Sega
M
M
Cavalieri
E
E
Shoji
K
K
Suzuki
H
H
D001943:Breast Neoplasms; D045744:Cell Line, Tumor; D002478:Cells, Cultured; D004789:Enzyme Activation; D029791:Ericaceae; D005260:Female; D005347:Fibroblasts / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000096:biosynthesis; D007371:Interferon-gamma / Q000494:pharmacology; D053614:Janus Kinase 2 / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000096:biosynthesis; D010766:Phosphorylation; D010936:Plant Extracts / Q000494:pharmacology; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11 / Q000378:metabolism*; D050794:STAT1 Transcription Factor / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D014867:Water
D016328:NF-kappa B; D010936:Plant Extracts; D050794:STAT1 Transcription Factor; C494079:STAT1 protein, human; D014409:Tumor Necrosis Factor-alpha; D014867:Water; D018799:Intercellular Adhesion Molecule-1; D007371:Interferon-gamma; C496319:NOS2 protein, human; D052247:Nitric Oxide Synthase Type II; C507924:JAK2 protein, human; D053614:Janus Kinase 2; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11