Abstract C37: Gene profiling predicts biomarkers in oral squamous cell carcinoma with diagnostic and therapeutic importance.

Oral squamous cell carcinoma (OSCC) is a disease with high incidence and mortality in India. There is no clinically proven biomarker for oral cancer and the 5-year survival rate has not improved for the past few years. Better understanding of deregulated process, pathways, and genes involved in the advanced stage tumor (stage III and IV) and further comparison with early stage tumor (Stage I and II) might lead to the discovery of biomarkers that can identify the tumor at an early onset. In this study we examined the gene expression profile of advanced OSCC tumors using an Affymetrix Human Gene 1.0ST array and compared the profile with control tissue surrounding normal margins. Microarray data analysis was performed using xRAY Biotique Systems to identify advanced OSCC gene profile that exhibited statistically significant differential expression of candidate marker genes. Intensive pathway analysis was performed using Ingenuity Systems to generate pathways deregulated in advanced OSCC. From the pathway analysis, it was found that hepatic stellate cell activation (myofibroblast activation), G2/M transition, interferon signaling, dendritic cell maturation, and oncostatin M signaling are the top significant pathways expressed in advanced tumor gene profile. These 5 pathways play pivotal role in promoting two important processes, fibrosis, and inflammation. Expression of significant targets identified from pathway analysis and current literature studies was validated by Quantitative-PCR and subsequently examined in early, advanced, and normal tissue samples. This comparison has led to identification of FN1 expression that can significantly distinguish early and advanced oral squamous cell carcinoma (OSCC) both at mRNA and protein level. Myofibroblast activation is essential for fibrosis condition and its presence was confirmed by the expression of alpha smooth muscle actin protein in early and advanced OSCC tissue samples. Furthermore, immunohistochemical analysis of inflammatory response mediators, SPP1 and ICAM1, showed significant higher expression in early and advanced OSCC tissues than in normal tissues. Meta-profiling analysis using present and external microarray data revealed that loss of KRT4 in pre-malignant stage might be an indicator for oral cancer progression. Down regulation of KRT4 gene in early and advanced OSCC was confirmed by Q-PCR. Early and advanced OSCC samples showed down regulation of anti-aging gene, Klotho, which acts as antagonist to proliferation promoting Wnt signaling pathway. Interestingly, it was observed that all 2-5A synthetase family genes, involved in immune response, were up regulated in early and advanced OSCC. A better understanding of molecular interactions in advanced OSCC samples has provided a clear insight of role of significant pathways and genes involved in the development of markers for early detection (FN1), prediction (loss of KRT4 in dysplasia condition) and therapeutic (targeting fibrosis and inflammation) purposes for improving the survival rate of patients. Through these findings, it can be incurred that fibrosis and inflammation are the key factors for oral cancer progression and using combination therapy of anti-fibrotic and anti-inflmmatory drugs might provide important insights into potential novel therapies for OSCC. Citation Information: Mol Cancer Ther 2013;12(11 Suppl):C37. Citation Format: Sivapriya Pavuluri, Christophe Lefevre, Julie Sharp, Sivalinga Prasad Vasireddi, Kevin R. Nicholas. Gene profiling predicts biomarkers in oral squamous cell carcinoma with diagnostic and therapeutic importance. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr C37.