Activation of the Ig I alpha 1 promoter by the transcription factor Ets-1 triggers Ig I alpha 1-C alpha 1 germline transcription in epithelial cancer cells

• Published in: Cellular & molecular immunology 2014-03, Vol.11 (2), p.197-205
• Main Authors: Duan, Zhi, Zheng, Hui, Xu, San, Jiang, Yiqun, Liu, Haidan, Li, Ming, Hu, Duosha, Li, Wei, Bode, Ann M, Dong, Zigang, Cao, Ya
• Format: Article
• Language: English
• ISSN: 1672-7681; 2042-0226
• DOI: 10.1038/cmi.2013.52

Immunoglobulins (Igs) are known to be synthesized and secreted only by B lymphocytes. Class switch recombination (CSR) is a key event that enables B cells to express Igs, and one of the crucial steps for CSR initiation is the germline transcription of Ig genes. Surprisingly, recent studies have demonstrated that the Ig genes are also expressed in some epithelial cancer cells; however, the mechanisms underlying how cancer cells initiate CSR and express Igs are still unknown. In this study, we confirmed that the Ig I alpha 1 promoter in cancer cell lines was activated by the Ets-1 transcription factor, and the activity of the Ig I alpha 1 promoter and Ig I alpha 1-C alpha 1 germline transcription were attenuated after knockdown of Ets-1 by specific small interfering RNAs (siRNA). Furthermore, the expression of Ets-1 and Ig alpha heavy chain in cancer cells was dose dependently upregulated by TGF- beta 1. These results indicate that activation of the Ig I alpha 1 promoter by the transcription factor Ets-1 is a critical pathway and provides a novel mechanism for Ig expression in non-B cell cancers.