RNA-binding proteins (RBPs) are critical regulators of gene expression in eukaryotes. However, the contribution of RBPs in oral epithelial homeostasis and oral pathological diseases remain mostly elusive. Our recent efforts demonstrate that dysregulated RBP HuR (Hu-Antigen R) disintegrate oral epithelium and contribute to oral tumorigenesis. HuR can bind AU-rich elements of mRNA sequences and regulates its stability of translation. Our preliminary data revealed that HuR binds and controls the expression of a subset of mRNAs encoding proteins involved in glucose metabolism. In collaboration with the Mehrotra group we show that epithelial specific HuR cross talk with immune response and contribute to oral tumorigenesis. Using T-cell immune plasticity functions, we plan to study the functional properties of HuR in oral epithelial and T-cells for anti-tumor activity. Here, we demonstrated that epithelial-specific HuR knockout modulates the epithelial homeostasis and oral tumorigenesis, whereas HuR KO T cells exhibit enhanced IFN? secretion by regulating glucose metabolism that alters the balance between the immunosuppressive regulatory T cells (Treg's) and effector T cells. While the oral epithelial alterations by HuR likely reflects the metabolic cues from T-cells, a major unanswered question pertains to the mechanism of HuR in human oral cancer where there are immune suppression and metabolic reprogramming. Collectively, HuR targets glucose metabolism genes in the oral epithelium and its involvement in T-cell specific immune plasticity stimulated a coalescence of efforts from the Palanisamy and Mehrotra groups to elucidate the underlying mechanisms of HuR and oral tumorigenesis, and T-cell mediated immune plasticity, respectively. The overarching hypothesis is that HuR-mediates gene regulation and cross-talk between oral epithelial and immune T cells compartments by a novel mechanism, and silencing HuR associated gene network is critical for epithelial and metabolic reprogramming to limit oral cancer progression. The outcome of our studies will result in advanced therapeutic intervention studies and translation from bench to bedside.
The lack of molecular mechanistic insights into the initiation and progression of oral squamous cell carcinoma has been the main hindrance in the development of new, directed therapy. HuR an RNA-binding protein that is overexpressed in oral cancers, post-transcriptionally control gene expression of epithelial and metabolic genes. The experiments described in this proposal will evaluate the biological properties of HuR and the contribution of cross-talk between oral epithelium and T-lymphocytes using a mouse model of oral tumorigenesis.
