Abstract 2956: Genome-wide expression profiling in tunicamycin treated capillary endothelial cells
Authors: Aditi Banerjee, Krishna Baksi, Alexandra Rivera, Dipak K. Banerjee
Journal: Cancer Research (2010)

Abstract Genome-wide expression profiling in tunicamycin treated capillary endothelial cells Aditi Banerjee1, Krishna Baksi2, Alexandra Rivera1, and Dipak K. Banerjee1. 1Dept Biochem, Sch Med, Univ Puerto Rico, San Juan, PR, USA and 2Dept Anatomy and Cell Biol, Sch Med, Universidad Central del Caribe, Bayamon, PR, USA Angiogeneis is a hall mark of breast tumor growth and progression. Our laboratory has been focusing on a dynamic relationship between asparagine-linked (N-linked) protein glycosylation and angiogenesis to identify a target for developing a new generation anti-angiogenic therapeutic treating breast cancer. In this study we have used a potent protein N-glycosylation inhibitor tunicamycin. When added, tunicamycin arrests capillary endothelial cells in G1 and induces apoptosis by unfolded protein response mediated by transcriptional (ATF6) and translational attenuation (PERK). The cell death is a failure of cell survival as indicated by IGF-1 signaling. Proteins as well as the mRNA were down regulated for PI3K, AKt as well as the phospho BAD, mTOR, phosphocaspage 9, and GSK3β. Studies have also confirmed that tunicamycin could stand the tumor microenvironment. There was down regulation of phosphotyrosine kinase activity so was the expression of phospho VEGFR1 and VEGFR2. Extension of these in vitro studies has proved that (i) tunicamycin inhibits angiogenesis in vivo in Matrigel™ implants in athymic nude mice; and (ii) reduces breast tumor growth. To analyze tunicamycin-induced apoptosis further we have used gene regulation and cDNA microarray approaches. Differential gene expression was compared after 3h and 32h of tunicamycin treatment. Out of 20,908 genes only 133 and 464 genes are found to be involved at 3h and 32h, respectively and sharing only 10 genes. Among 133 and 464 genes 72.2% and 77.6% are upregulated whereas 27.8% and 22.41% are down regulated after 3h and 32h of tunicamycin treatment, respectively. Up- and down-regulated genes are grouped into functional categories to identify biochemical processes possibly affected by tunicamycin. In addition, 45 genes encode for transcription, 75% and 20% of which are upregulated at 3h and 32h, respectively; 15 genes encode for cell cycle and 40% and 20% of which are upregulated at 3h and 32h, respectively. Only 10 genes encode for translation, 80% of which are upregulated at 32h. Interestingly, only 1 gene is upregulated at 32h for protein folding, DNA inhibition and angiogenesis. Validation studies for ALG2, GRIM19, DAX10, DDIT4, NOTCH3, COLEC11, MLL, TCF7L2, SUMO3, PMM2, CCRK, APAF1, AGGF1, EIF4ENIF1, DNMI2 using real time PCR confirmed patterns of gene expression observed in our model. To our knowledge, this study is the first report of its kind and for assessing the significance of genes identified for developing glycothrapeutics treating breast cancer. Supported in part by Susan G Komen for the Cure BCTR056206 (DKB) and NIH/NCRR/RCMI (KB) grants. 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 2956.