Text Box:  TC-1 Text Box:  FGF Text Box: AZD2171
 

 


Apert Syndrome

Breast cancer

Gastric cancer

Text Box:  FGFR2Jackson-Weiss

Pfeiffer Syndrome

Oral cancer

5/28/2007/-21

Int J Cancer. 2007 May 22; [Epub ahead of print]Click here to read  Links

Transforming properties of TC-1 in human breast cancer: Interaction with FGFR2 and beta-catenin signaling pathways.

     Yang ZQ, Moffa AB, Haddad R, Streicher KL, Ethier SP.

Breast Cancer Program, Department of Pathology, Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, MI.

Breast cancer development is associated with gene amplification and over expression that is believed to have a causative role in oncogenesis. Previous studies have demonstrated that over expression of TC-1(C8orf4) mRNA occurs in approximately 50% of breast cancer cell lines and primary tumor specimens. Here, we show that TC-1 has transforming properties in human mammary epithelial (HME) cells and its expression is mechanistically linked to FGFR signaling cascades. In vitro experiments demonstrate that TC-1 over expression mediates both anchorage-independent and growth factor-independent proliferation of HME cells. TC-1 was down regulated by the FGFR inhibitor PD173074 in the breast cancer cell line SUM-52 that also has an FGFR2 gene amplification and over expression. Furthermore, forced expression of FGFR2 in HME cells increased the level of expression of endogenous TC-1 mRNA. TC-1 has been implicated as a modulator of Wnt/beta-catenin signaling in 293 cells and in gastric cancer cells. However, while we did find increased expression of a subset of beta-catenin target genes in TC-1 over expressing cells, we did not find an association of TC-1 with global expression of beta-catenin target genes in our cells. Taken together, our data suggest that TC-1 over expression is transforming and may link with the FGFR pathway in a subset of breast cancer. (c) 2007 Wiley-Liss, Inc.

PMID: 17520678 [PubMed - as supplied by publisher]

Clin Cancer Res. 2007 May 15;13(10):3051-7.Click here to read  Links

AZD2171 Shows Potent Antitumor Activity Against Gastric Cancer Over-Expressing Fibroblast Growth Factor Receptor 2/Keratinocyte Growth Factor Receptor.

     Takeda M, Arao T, Yokote H, Komatsu T, Yanagihara K, Sasaki H, Yamada Y, Tamura T, Fukuoka K, Kimura H, Saijo N, Nishio K.

Authors' Affiliations: Shien Lab and Medical Oncology, National Cancer Center Hospital, Tsukiji, Chuo-ku, Tokyo, Japan.

PURPOSE: AZD2171 is an oral, highly potent, and selective vascular endothelial growth factor signaling inhibitor that inhibits all vascular endothelial growth factor receptor tyrosine kinases. The purpose of this study was to investigate the activity of AZD2171 in gastric cancer. EXPERIMENTAL DESIGN: We examined the antitumor effect of AZD2171 on the eight gastric cancer cell lines in vitro and in vivo. RESULTS: AZD2171 directly inhibited the growth of two gastric cancer cell lines (KATO-III and OCUM2M), with an IC(50) of 0.15 and 0.37 mumol/L, respectively, more potently than the epidermal growth factor receptor tyrosine kinase inhibitor gefitinib. Reverse transcription-PCR experiments and immunoblotting revealed that sensitive cell lines dominantly expressed COOH terminus-truncated fibroblast growth factor receptor 2 (FGFR2) splicing variants that were constitutively phosphorylated and spontaneously dimerized. AZD2171 completely inhibited the phosphorylation of FGFR2 and downstream signaling proteins (FRS2, AKT, and mitogen-activated protein kinase) in sensitive cell lines at a 10-fold lower concentration (0.1 mumol/L) than in the other cell lines. An in vitro kinase assay showed that AZD2171 inhibited kinase activity of immunoprecipitated FGFR2 with submicromolar K(i) values ( approximately 0.05 mumol/L). Finally, we assessed the antitumor activity of AZD2171 in human gastric tumor xenograft models in mice. Oral administration of AZD2171 (1.5 or 6 mg/kg/d) significantly and dose-dependently inhibited tumor growth in mice bearing KATO-III and OCUM2M tumor xenografts. CONCLUSIONS: AZD2171 exerted potent antitumor activity against gastric cancer xenografts overexpressing FGFR2. The results of these preclinical studies indicate that AZD2171 may provide clinical benefit in patients with certain types of gastric cancer.

PMID: 17505008 [PubMed - in process]

Am J Pathol. 2007 May;170(5):1618-28.Click here to read  Links

Epigenetic silencing through DNA and histone methylation of fibroblast growth factor receptor 2 in neoplastic pituitary cells.

     Zhu X, Lee K, Asa SL, Ezzat S.

Department of Medicine, Mount Sinai Hospital and University of Toronto, Canada.

Four members of the fibroblast growth factor receptor (FGFR) family of tyrosine kinases transduce signals of a diverse group of more than 23 fibroblast growth factor (FGF) ligands. Each prototypic receptor is composed of three immunoglobulin-like extracellular domains, two of which are involved in ligand binding. Alternative RNA splicing of one of two exons results in two different forms of the second half of the third immunoglobulin-like domain, the IIIb or IIIc isoforms. The contribution of each receptor and their isoforms in tumorigenesis remains unknown. In the pituitary, FGFR2 is expressed primarily as the IIIb isoform in normal adenohypophysial cells. In contrast, FGFR2 is significantly down-regulated in mouse corticotroph AtT20 tumor cells where the 5' promoter is methylated. Treatment of AtT20 cells with 5'-azacytidine resulted in FGFR2 re-expression, mainly as the FGFR2-IIIb isoform. Chromatin immunoprecipitation revealed evidence of histone methylation, but not of deacetylation, in the silencing of FGFR2 in AtT20 cells. Exposure of these cells to the cognate FGFR2-IIIb ligand FGF-7 resulted in diminished Rb phosphorylation and accumulation of p21 and p27, indicating diminished cell cycle progression. Examination of primary human pituitary adenomas revealed FGFR2 down-regulation in 52% (11 of 21) of samples and FGFR2 promoter DNA methylation in 45% (10 of 22) of samples. These data highlight the contribution from DNA and histone methylation as epigenetic mechanisms responsible for FGFR2 silencing in pituitary neoplasia.

PMID: 17456767 [PubMed - in process]

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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Differential Regulation of CD40-Mediated TNF Receptor-Associated Factor Degradation in B Lymphocytes.

Moore CR, Bishop GA.

Interdisciplinary Graduate Program in Immunology.

Engagement of CD40 on murine B cells by its ligand CD154 induces the binding of TNFR-associated factors (TRAFs) 1, 2, 3, and 6, followed by the rapid degradation of TRAFs 2 and 3. TRAF degradation occurs in response to signaling by other TNFR superfamily members, and is likely to be a normal regulatory component of signaling by this receptor family. In this study, we found that receptor-induced TRAF degradation limits TRAF2-dependent CD40 signals to murine B cells. However, TRAFs 1 and 6 are not degraded in response to CD40 engagement, despite their association with CD40. To better understand the mechanisms underlying differential TRAF degradation, mixed protein domain TRAF chimeras were analyzed in murine B cells. Chimeras containing the TRAF2 zinc (Zn) domains induced effective degradation, if attached to a TRAF domain that binds to the PXQXT motif of CD40. However, the Zn domains of TRAF3 and TRAF6 could not induce degradation in response to CD40, regardless of the TRAF domains to which they were attached. Our data indicate that TRAF2 serves as the master regulator of TRAF degradation in response to CD40 signaling, and this function is dependent upon both the TRAF Zn domains and receptor binding position.

PMID: 16148124 [PubMed - in process]

 

 

B Cell Maturation Antigen, the Receptor for a Proliferation-Inducing Ligand and B Cell-Activating Factor of the TNF Family, Induces Antigen Presentation in B Cells.

Yang M, Hase H, Legarda-Addison D, Varughese L, Seed B, Ting AT.

Immunobiology Center, Mount Sinai School of Medicine, New York, NY 10029.

B cell maturation Ag (BCMA), a member of the TNFR superfamily expressed on B cells, binds to a proliferation-inducing ligand (APRIL) and B cell-activating factor of the TNF family (BAFF) but the specific B cell responses regulated by BCMA remain unclear. This study demonstrates that ligation of A20 B cells transfected with BCMA induces the expression of CD40, CD80/B7-1, CD86/B7-2, MHC class II, and CD54/ICAM-1, which subsequently enhances the presentation of OVA peptide Ag to DO11.10 T cells. BCMA expression in murine splenic B cells can be induced with IL-4 and IL-6, allowing subsequent treatment with APRIL or agonist anti-BCMA to similarly induce Ag presentation. A comparative analysis of hybrid receptors of TNFR2 fused to the cytoplasmic domains of APRIL/BAFF receptors found that only BCMA, but not transmembrane activator and calcium-modulator and cyclophilin ligand interactor or BAFF-R, is capable of activating Ag presentation. Although all three receptors can trigger NF-kappaB signaling, only BCMA activates the JNK pathway conferring on BCMA the specific ability to activate this Ag presentation response.

PMID: 16116167 [PubMed - in process]

 

 

 

 

 

ICAM-1 gene expression in endothelial cells: Effects on the inhibition of STAT3 phosphorylation.
Resveratrol suppresses IL-6-induced
Wung BS, Hsu MC, Wu CC, Hsieh CW.

Department of Applied Microbiology, National Chiayi University, Chiayi, Taiwan.

Resveratrol, a polyphenolic phytoaxelin present in red wine, has been suggested to protect against atherosclerosis and cardiovascular disease because of its antioxidant effects. Intercellular adhesion molecule (ICAM-1), induced by cytokines, has been hypothesized to play a role in the early events during atherosclerosis. In this study we tested the effects of resveratrol upon both IL-6-induced ICAM-1 gene expression and its underlying signaling pathways in endothelial cells (ECs). Resveratrol was found to inhibit both TNFalpha- and IL-6-induced ICAM-1 gene expression at the promoter, transcriptional and protein levels. Resveratrol also abrogates the tyr705 phosphorylation of STAT3 in IL-6-treated ECs, in a dose- and time-dependent manner. Although quercetin had similar effects, resveratrol showed higher inhibitory properties following 2-4 h pretreatments. Resveratrol has been shown to induce the activity of endothelial nitric oxide synthase (eNOS) and increase NO production. Consistent with this, the treatment of ECs with a NO donor (SNAP) reduces IL-6-induced STAT3 phosphorylation. Conversely, exposure of ECs to a NOS inhibitor reversed the effects of resveratrol upon IL-6-induced STAT3 phosphorylation. Furthermore, ECs transfected with constitutively active Rac1 (RacV12) showed increases in ICAM-1 promoter activity, intracellular reactive oxygen species (ROS) levels and STAT3 phosphorylation, and these increases were attenuated by resveratrol treatment. In summary, we demonstrate for the first time that resveratrol inhibits IL-6-induced ICAM-1 gene expression, in part, by interfering with Rac-mediated pathways via the attenuation of STAT3 phosphorylation. This study therefore provides important new insights that may contribute to the proposed beneficial effects of resveratrol in endothelial responses to cytokines during inflammation.

PMID: 16150460 [PubMed - as supplied by publisher]