title: EGF-induced MMP-9 expression is mediated by the JAK3/ERK pathway, but not by  the JAK3/STAT-3 pathway in a SKBR3 breast cancer cell line.
abstract: The number of epidermal growth factor receptors (EGFRs) and their ligands are highly expressed in malignant tumor cells. The EGF signaling pathway is also activated in up to one-third of patients with breast cancer. In this study, we investigated the novel function of the JAK3 inhibitor, WHI-P131, on EGF-induced MMP-9 expression and the regulatory mechanism of EGF-induced MMP-9 expression in SKBR3 cells. We observed that EGF increased MMP-9 mRNA and protein expression in a dose-dependent manner. EGF also induced the phosphorylation of EGFR, ERK, and STAT-3, and these effects were inhibited by the EGFR inhibitor, AG1478.To investigate the involvement of the STAT-3 pathway on EGF-induced MMP-9 expression, we pretreatedSKBR3 cells with JAK1, JAK2, and JAK3 inhibitors prior to EGF treatment. The results showed that the JAK3 inhibitor, WHI-P131, as well as JAK3 siRNA transfection, but not the JAK1 and JAK2 inhibitors, significantly decreased EGF-induced MMP-9 expression. In addition, EGF-induced STAT-3 phosphorylation was only inhibited by WHI-P131. We then transfected cells with adenoviral STAT-3 (Ad-STAT-3), followed by treatment with EGF. Interestingly, EGF-induced MMP-9 expression was decreased by Ad-STAT-3 overexpression in a dose-dependent manner, while it was significantly increased by STAT-3 siRNA transfection. Our results also showed that basal levels of MMP-9 expression were significantly increased by constitutive active-MEK (CAMEK)overexpression. EGF-induced ERK phosphorylation was prevented by WHI-P131, but not by JAK1 andJAK2 inhibitors. On the other hand, EGF-induced MMP-9 expression was decreased by the MEK1/2 inhibitor,UO126. Therefore, for the first time, we suggest that the JAK3 inhibitor, WHI-P131, inhibits EGF-induced STAT-3 phosphorylation as well as ERK phosphorylation. The JAK3/ERK pathway may play an important role in EGFinduced MMP-9 expression in SKBR3 cells.
authors.affiliation: Department of Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Ilwon-dong 50, Kangnam-gu, Seoul, Republic of Korea.
authors.forename: Sangmin
authors.initials: S
authors.lastname: Kim
authors.forename: Jae Hyuck
authors.initials: JH
authors.lastname: Choi
authors.forename: Hye In
authors.initials: HI
authors.lastname: Lim
authors.forename: Se-Kyung
authors.initials: SK
authors.lastname: Lee
authors.forename: Wan Wook
authors.initials: WW
authors.lastname: Kim
authors.forename: Sungjin
authors.initials: S
authors.lastname: Cho
authors.forename: Jee Soo
authors.initials: JS
authors.lastname: Kim
authors.forename: Jung-Han
authors.initials: JH
authors.lastname: Kim
authors.forename: Jun-Ho
authors.initials: JH
authors.lastname: Choe
authors.forename: Seok Jin
authors.initials: SJ
authors.lastname: Nam
authors.forename: Jeong Eon
authors.initials: JE
authors.lastname: Lee
authors.forename: Jung-Hyun
authors.initials: JH
authors.lastname: Yang
mesh_terms: D001943:Breast Neoplasms / Q000201:enzymology* / Q000235:genetics; D045744:Cell Line, Tumor; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D066246:ErbB Receptors / Q000037:antagonists & inhibitors; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism*; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D053613:Janus Kinase 1 / Q000037:antagonists & inhibitors; D053614:Janus Kinase 2 / Q000037:antagonists & inhibitors; D053616:Janus Kinase 3 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D020780:Matrix Metalloproteinase 9 / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D011799:Quinazolines / Q000494:pharmacology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D050796:STAT3 Transcription Factor / Q000378:metabolism*; D020032:Tyrphostins / Q000494:pharmacology
chemical_list: D011799:Quinazolines; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D050796:STAT3 Transcription Factor; C494086:STAT3 protein, human; D020032:Tyrphostins; C116180:WHI P131; C101044:RTKI cpd; D004815:Epidermal Growth Factor; D066246:ErbB Receptors; D053613:Janus Kinase 1; D053614:Janus Kinase 2; D053616:Janus Kinase 3; D048049:Extracellular Signal-Regulated MAP Kinases; D020780:Matrix Metalloproteinase 9