The Epstein-Barr virus EBNA2 protein induces a subset of NOTCH target genes in thyroid cancer cell lines but fails to suppress proliferation

详细信息    查看全文

• 作者：Sean Golden ; BA^a ; Xiao-Min Yu ; MD ; PhD^a ; Scott Odorico^a ; Vansh Jain^a ; Ana Marin^a ; Shidong Ma ; PhD^b ; Shannon Kenney ; MD^b ; Herbert Chen ; MD^c ; ^{herbchen@uab.edu}
• 刊名：Surgery
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：161
• 期：1
• 页码：195-201
• 全文大小：505 K
• 卷排序：161

文摘

Epstein-Barr virus is associated with lymphoid and epithelial malignancies and has been reported to infect thyroid cells. The Epstein-Barr virus protein, EBNA2, regulates viral and cellular promoters by binding to RBP-jκ. Similarly, NOTCH1, a tumor suppressor protein in thyroid epithelial cells, competes with EBNA2 for binding to overlapping sites on RBP-jκ. EBNA2 activates a subset of NOTCH-responsive genes in lymphocytes and myocytes; however, the effect of EBNA2 expression on NOTCH targets in epithelial cells is unknown. Here we have explored whether EBNA2 activates NOTCH1 targets in thyroid cancer lines and examined its effect on cellular proliferation.MethodsTwo human thyroid cancer lines, follicular FTC-236 and anaplastic HTh7, were transfected with EBNA2, NOTCH1, or control vectors. Notch targets were measured using quantitative reverse transcriptase polymerase chain reaction. Cellular proliferation was measured by MTT analysis.ResultsEBNA2 activated only a subset of NOTCH1 targets. Expression of HES1 and HEY1 were increased 10-fold in FTC-236 and HTh7 cells, respectively, but the majority of NOTCH1 targets examined were not affected. In contrast to NOTCH1, EBNA2 did not suppress proliferation.ConclusionEBNA2 does not activate most Notch1-responsive genes or suppress proliferation in human thyroid cancer cells. Instead, EBNA2 may compete with NOTCH1 for limiting amounts of RBP-jκ in epithelial cells and inhibit certain aspects of NOTCH1 signaling.