ORCID Profile
0000-0003-3545-5171
Current Organisations
Vlaams Instituut voor Biotechnologie
,
KU Leuven
,
UCSF Helen Diller Family Comprehensive Cancer Center
,
University of California
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Publisher: Oxford University Press (OUP)
Date: 06-2008
Publisher: Wiley
Date: 20-04-2018
DOI: 10.1002/PATH.5080
Publisher: American Society of Hematology
Date: 02-2005
DOI: 10.1182/BLOOD-2004-06-2315
Abstract: We identified regulator of G-protein signaling-5 (RGS-5) as an angiogenic pericyte marker at sites of physiologic and pathologic angiogenesis. In a mouse model of pancreatic islet cell carcinogenesis, RGS-5 is specifically induced in the vasculature of premalignant lesions during the “angiogenic switch” and further elevated in tumor vessels. Similarly, RGS-5 is overexpressed in highly angiogenic astrocytomas but not in hypoxia-inducible factor-1α (HIF-1α)–deficient tumors, which grow along preexisting brain capillaries without inducing neovessels. Elevated levels of RGS-5 in pericytes are also observed during wound healing and ovulation indicating a strong correlation between RGS-5 expression and active vessel remodeling beyond tumor angiogenesis. Moreover, antitumor therapy, which reverses tumor vasculature to an almost normal morphology, results in down-regulation of RGS-5 transcription. Taken together, these data demonstrate for the first time a factor that is specific for “activated” pericytes. This further supports the notion that pericytes, like endothelial cells, undergo molecular changes during neovascularization that makes them a novel target for antiangiogenic therapy.
Publisher: American Association for Cancer Research (AACR)
Date: 12-2006
DOI: 10.1158/0008-5472.CAN-06-1540
Abstract: The collagen type IV cleavage fragment tumstatin and its active subfragments bind to integrin αVβ3 and inhibit activation of focal adhesion kinase, phophoinositol-3 kinase, Akt, and mammalian target of rapamycin (mTOR) in what is thought to be an endothelial cell–specific manner. The resultant endothelial cell apoptosis accounts for the ability of tumstatin to function as an endogenous inhibitor of angiogenesis and an indirect suppressor of tumor growth. We hypothesized that the inability of tumstatin to directly suppress tumor cell growth might be the result of the constitutive activation of the Akt/mTOR pathway commonly seen in tumors. Consistent with this idea, several integrin αVβ3–expressing glioma cell lines with PTEN mutations and high levels of phospho-Akt (pAkt) were unaffected by exposure to an active fragment of tumstatin (T3), whereas αVβ3-expressing glioma cell lines with a functional PTEN/low levels of pAkt exhibited T3-induced growth suppression that could be bypassed by small interfering RNA–mediated suppression of PTEN, introduction of a constitutively expressed Akt, or introduction of the Akt and mTOR target eukaryotic translation initiation factor 4E. The direct tumor-suppressive actions of T3 were further shown in an αVβ3-deficient in vivo mouse model in which T3, while unable to alter the tumstatin-insensitive vasculature contributed by the αVβ3-deficient host, nonetheless suppressed the growth and proliferative index of i.c. implanted αVβ3-expressing PTEN-proficient glioma cells. These results show that tumstatin, previously considered to be only an endogenous inhibitor of angiogenesis, also directly inhibits the growth of tumors in a manner dependent on Akt/mTOR activation. (Cancer Res 2006 66(23): 11331-40)
Publisher: American Association for Cancer Research (AACR)
Date: 31-08-2009
DOI: 10.1158/0008-5472.CAN-09-0347
Abstract: Activating epidermal growth factor receptor (EGFR) mutations are common in many cancers including glioblastoma. However, clinical responses to EGFR inhibitors are infrequent and short-lived. We show that the Src family kinases (SFK) Fyn and Src are effectors of oncogenic EGFR signaling, enhancing invasion and tumor cell survival in vivo. Expression of a constitutively active EGFR mutant, EGFRvIII, resulted in activating phosphorylation and physical association with Src and Fyn, promoting tumor growth and motility. Gene silencing of Fyn and Src limited EGFR- and EGFRvIII-dependent tumor cell motility. The SFK inhibitor dasatinib inhibited invasion, promoted tumor regression, and induced apoptosis in vivo, significantly prolonging survival of an orthotopic glioblastoma model expressing endogenous EGFRvIII. Dasatinib enhanced the efficacy of an anti-EGFR monoclonal antibody (mAb 806) in vivo, further limiting tumor growth and extending survival. Examination of a large cohort of clinical s les showed frequent coactivation of EGFR and SFKs in glioblastoma patients. These results establish a mechanism linking EGFR signaling with Fyn and Src activation to promote tumor progression and invasion in vivo and provide rationale for combined anti-EGFR and anti-SFK targeted therapies. [Cancer Res 2009 (17):6889–98]
Publisher: Elsevier BV
Date: 03-2008
Location: United States of America
No related grants have been discovered for Gabriele Bergers.