Abstract 1415: The Notch ligand Jag 2 promotes growth and invasion in uveal melanoma cells

Abstract

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