Poster Sessions

CANCER-30

Biju Issac

B. Issac, S. Zhao, S. Johnson, E.J. Chung, K. Camphausen, D. Citrin

Microarray Analysis of Cancerous and Normal Pancreatic Cell Lines in Response to Ionizing Radiation

Pancreatic cancer has one of the lowest progression free survival rates and a high local recurrence rate even after surgery and chemoradiotherapy. We used microarray analysis to measure the changes in the gene expression profiles of ~5000 known genes and ESTs in 4 pancreatic tumor (ASPC1, BxPC3, MiaPaCa2 and PSN1) and 1 normal tissue (HPDE) cell lines after exposure to different IR doses (2, 4, 6 and 8 Gray) and collected at multiple time points (6, 24 and 48 hr). The array data was processed and normalized using R statistical software. The differentially expressed (DE) genes were derived using the Significant Analysis of Microarray (SAM) package. The Ingenuity Pathway analysis (IPA) of the DE genes reveals; (1) a dose dependent response that differs between cell lines and, (2) enriched networks of genes that are cell type independent. Initial observations show peturbations in MAPK and NFkB signaling pathways on application of lower dose while higher dose resulted in activation of TNF signaling pathway. Gene set analysis (GSA) of DE genes reveals downregulation of cytokine related processes associated with lower IR doses. Microarray analysis is an effective tool for identifying new genes of interest to generate testable hypotheses possibly unraveling molecular mechanisms post-radiotherapy