Gene expression in neonatal NKT cells and lymphoma samples from mice with high E protein levels [Microarray Expression]

Inhibitor of DNA binding proteins (ID), including Id1-4, are transcriptional regulators involved in promoting cell proliferation and survival in various cell types. Although upregulation of Id proteins have been widely reported to be associated with a broad spectrum of tumors, recent studies have identified that Id3 also plays a tumor suppressor role in the development of Burkitts lymphoma in humans and Hepatosplenic T cell lymphomas in mice. However, there is a lack of evidence to suggest the tumor suppressor roles for other Id genes, particularly Id2, which is highly expressed in many T lymphocytes. In this study we report that Id2 plays a tumor suppressive role in collaboration with Id3 in developing T cells in mice. We found that there was rapid lymphoma development in Id2f/fId3f/fLckCre mice caused by unchecked neonatal expansion of invariant Natural Killer T (iNKT) cells and a unique subset of innate-like, CD1d-independent T cells. These tumors also gave rise to lymphomas in Rag-deficient mice, reaffirming the inherent tumorigenic potential of these cells. Microarray analysis revealed a significantly modified program in expanding iNKT cells that ultimately contributed to tumorigenesis. We found chromosome instability and significant upregulation of several different signaling pathways, including pathways for multiple chemokines, cytokines and their receptors, in these tumors. While Id proteins are being considered as potential therapeutic targets in some cancer models, our results highlight the possibility of aggravated tumorigenesis upon suppression of Id2 and Id3.

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Li J, Roy S, Kim YM, Li S, Zhang B, Love C, Reddy A, Rajagopalan D, Dave S, Diehl AM, Zhuang Y