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  • 1
    Online Resource
    Online Resource
    American Association for Cancer Research (AACR) ; 2011
    In:  Cancer Research Vol. 71, No. 3 ( 2011-02-01), p. 1115-1125
    In: Cancer Research, American Association for Cancer Research (AACR), Vol. 71, No. 3 ( 2011-02-01), p. 1115-1125
    Abstract: Although Notch signaling has been widely implicated in neoplastic growth, direct evidence for in vivo initiation of neoplasia by the pathway in murine models has been limited to tumors of lymphoid, breast, and choroid plexus cells. To examine tumorigenic potential in the eye and brain, we injected retroviruses encoding activated forms of Notch1, Notch2, or Notch3 into embryonic mice. Interestingly, the majority of animals infected with active Notch3 developed proliferative lesions comprised of pigmented ocular choroid cells, retinal and optic nerve glia, and lens epithelium. Notch3-induced lesions in the choroid, retina, and optic nerve were capable of invading adjacent tissues, suggesting that they were malignant tumors. Although Notch3 activation induced choroidal tumors in up to 67% of eyes, Notch1 or Notch2 activation never resulted in such tumors. Active forms of Notch1 and Notch2 did generate a few small proliferative glial nodules in the retina and optic nerve, whereas Notch3 was 10-fold more efficient at generating growths, many of which were large invasive gliomas. Expression of active Notch1/Notch3 chimeric receptors implicated the RBPjk-association molecule and transactivation domains of Notch3 in generating choroidal and glial tumors, respectively. In contrast to our findings in the optic nerve and retina, introduction of active Notch receptors, including Notch3, into the brain never caused glial tumors. Our results highlight the differential ability of Notch receptor paralogs to initiate malignant tumor formation, and suggest that glial precursors of the optic nerve, but not the brain, are susceptible to transformation by Notch3. Cancer Res; 71(3); 1115–25. ©2011 AACR.
    Type of Medium: Online Resource
    ISSN: 0008-5472 , 1538-7445
    RVK:
    RVK:
    Language: English
    Publisher: American Association for Cancer Research (AACR)
    Publication Date: 2011
    detail.hit.zdb_id: 2036785-5
    detail.hit.zdb_id: 1432-1
    detail.hit.zdb_id: 410466-3
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  • 2
    Online Resource
    Online Resource
    American Association for Cancer Research (AACR) ; 2011
    In:  Cancer Research Vol. 71, No. 8_Supplement ( 2011-04-15), p. 1415-1415
    In: Cancer Research, American Association for Cancer Research (AACR), Vol. 71, No. 8_Supplement ( 2011-04-15), p. 1415-1415
    Abstract: Uveal melanoma is the most common primary intraocular cancer in the adults, and up to 50% of patients die from hematogenous visceral metastases which are extremely resistant to chemotherapy. Using oligonucleotide expression array analysis of mRNA from primary uveal melanomas, we found that the Jag 2 ligand was 1.9 fold more expressed in tumors which metastasized than those which did not. Other Notch pathway members were also significantly induced in the metastatic cohort. We then used quantitative RT PCR to analyze mRNA extracted from a second cohort of 30 snap-frozen primary tumors, and confirmed that elevated Jag 2 mRNA levels were significantly associated (p = 0.048) with the metastatic Class 2 signature as compared to non-metastatic Class 1 uveal melanoma. To directly examine the importance of Jag 2 in driving cellular growth and invasion, we introduced the ligand into a uveal melanoma cell line, Mel 290, which has low baseline levels of Notch activity as measured by expression of the pathway targets Hes1, Hey1 and Hey2. The Jag 2-GFP-MSCV-infected cells showed a 2.5 to 6 fold induction of Notch targets Hey 1 and Hes1, indicating that pathway activity had been induced. While overall growth of the Jag 2-GFP-MSCV infected cultures as measured by MTT increased only slightly, overexpression of Jag 2 induced an approximately 3 fold increase in clonogenic growth in soft agar. Finally, we assayed the migratory properties of the cells using a wound-healing (“scratch”) assay, as well as their ability to invade Matrigel. Jag 2 expressing cells showed increased motility in both of these tests, with a significant (p = 0.0003) approximately 2 fold induction of transwell invasion capacity. Our data suggest that expression of the Notch ligand Jag 2 may play an important role in uveal melanoma growth and metastasis. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1415. doi:10.1158/1538-7445.AM2011-1415
    Type of Medium: Online Resource
    ISSN: 0008-5472 , 1538-7445
    RVK:
    RVK:
    Language: English
    Publisher: American Association for Cancer Research (AACR)
    Publication Date: 2011
    detail.hit.zdb_id: 2036785-5
    detail.hit.zdb_id: 1432-1
    detail.hit.zdb_id: 410466-3
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  • 3
    Online Resource
    Online Resource
    American Association for Cancer Research (AACR) ; 2012
    In:  Clinical Cancer Research Vol. 18, No. 3 ( 2012-02-01), p. 654-665
    In: Clinical Cancer Research, American Association for Cancer Research (AACR), Vol. 18, No. 3 ( 2012-02-01), p. 654-665
    Abstract: Purpose: To determine whether uveal melanoma, the most common primary intraocular malignancy in adults, requires Notch activity for growth and metastasis. Experimental Design: Expression of Notch pathway members was characterized in primary tumor samples and in cell lines, along with the effects of Notch inhibition or activation on tumor growth and invasion. Results: Notch receptors, ligands, and targets were expressed in all five cell lines examined and in 30 primary uveal melanoma samples. Interestingly, the three lines with high levels of baseline pathway activity (OCM1, OCM3, and OCM8) had their growth reduced by pharmacologic Notch blockade using the γ-secretase inhibitor (GSI) MRK003. In contrast, two uveal melanoma lines (Mel285 and Mel290) with very low expression of Notch targets were insensitive to the GSI. Constitutively active forms of Notch1 and Notch2 promoted growth of uveal melanoma cultures and were able to rescue the inhibitory effects of GSI. MRK003 treatment also inhibited anchorage-independent clonogenic growth and cell invasion and reduced phosphorylation levels of STAT3 and extracellular signal-regulated kinase (Erk)1/2. Suppression of canonical Notch activity using short hairpin RNA targeting Notch2 or CBF1 was also able to reduce tumor growth and invasion. Finally, intraocular xenograft growth was significantly decreased by GSI treatment. Conclusion: Our findings suggest that Notch plays an important role in inducing proliferation and invasion in uveal melanoma and that inhibiting this pathway may be effective in preventing tumor growth and metastasis. Clin Cancer Res; 18(3); 654–65. ©2012 AACR.
    Type of Medium: Online Resource
    ISSN: 1078-0432 , 1557-3265
    RVK:
    Language: English
    Publisher: American Association for Cancer Research (AACR)
    Publication Date: 2012
    detail.hit.zdb_id: 1225457-5
    detail.hit.zdb_id: 2036787-9
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  • 4
    Online Resource
    Online Resource
    American Association for Cancer Research (AACR) ; 2010
    In:  Cancer Research Vol. 70, No. 8_Supplement ( 2010-04-15), p. 4141-4141
    In: Cancer Research, American Association for Cancer Research (AACR), Vol. 70, No. 8_Supplement ( 2010-04-15), p. 4141-4141
    Abstract: Uveal melanoma is the most common primary intra-ocular malignancy in adults, and causes significant mortality due to its propensity to metastasize. Our aim is to investigate the role of Notch signaling in promoting uveal melanoma proliferation and invasion. We examined five established uveal melanoma cell lines, and found using qPCR that the Notch 1-2-3 receptors, Jag1-2 ligands and the pathway target Hes1 were expressed to varying degrees in all lines. We then blocked Notch signaling using the gamma-secretase inhibitor (GSI) MRK003, and found that only three of the lines (OCM1, OCM3, OCM8) had their growth inhibited by the drug. Interestingly, these three lines had significantly higher levels of Hes1 mRNA as compared to the two lines resistant to GSI treatment (Mel 285, Mel 290). GSI treatment induced a dose-dependent reduction of anchorage-independent clonogenic growth, with 50% inhibition in OCM1, 70% in OCM3, and 40% in OCM8, as well as a significant reduction in Hes1 mRNA and protein levels. Apoptosis, as measured by cleavage and activation of caspase-9, was also induced. Finally, we observed inhibition of cellular invasion in GSI treated cultures using transwell migration and scratch assays. Preliminary studies of snap-frozen primary tumors indicate that Notch pathway components are expressed in primary uveal melanoma in vivo at levels as high or higher than those in our cell line models. In addition, oligonucleotide microarray analysis showed a significant increase in Jag2 and Notch3 expression levels in primary uveal melanomas that metastasized as compared to those that did not. Our findings suggest that the Notch pathway plays an important role in inducing cellular proliferation and invasion in uveal melanoma, and that inhibiting this pathway using pharmacological agents may be effective in preventing tumor growth and metastasis. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4141.
    Type of Medium: Online Resource
    ISSN: 0008-5472 , 1538-7445
    RVK:
    RVK:
    Language: English
    Publisher: American Association for Cancer Research (AACR)
    Publication Date: 2010
    detail.hit.zdb_id: 2036785-5
    detail.hit.zdb_id: 1432-1
    detail.hit.zdb_id: 410466-3
    Library Location Call Number Volume/Issue/Year Availability
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