Zonal Heterogeneity for Gene Expression in Human Pancreatic Carcinoma Growing in the Pancreas of Nude Mice

Using Affymetrix HG-U133-Plus 2.0 array and Laser Capture Microdissection techniques, we determined whether growth in different zones of the same tumor affected expression of genes by human pancreatic cancer cells. Human L3.6pl pancreatic cancer cells were implanted into the pancreas of nude mice. Gene expression patterns in tumor cells within the central and peripheral zones were compared and statistical differences were determined for 1222 genes. Bioinformatic functional prediction analysis revealed that 346 upregulated genes in the peripheral zone were related to cytoskeleton organization and biogenesis, cell cycle, cell adhesion, cell motility, DNA replication, localization, integrin-mediated signaling pathway, development, morphogenesis, and IkB kinase/NF-kB cascade; and 876 upregulated genes in the central zone were related with regulation of cell proliferation, regulation of transcription, transmembrane receptor protein tyrosine kinase signaling pathway, response to stress, small GTPase mediated signal transduction, hexose metabolism, cell death, response to external stimulus, carbohydrate metabolism, and response to wounding. Results from the microarray were confirmed for reliability by in situ hybridization analysis. Collectively, these data demonstrate zonal heterogeneity for gene expression profiles in tumors and suggest that characterization of zonal gene expression profiles are essential to obtain reproducible data, to predict disease prognosis, and to design specific therapeutics.

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Nakamura T, Kuwai T, Kitadai Y, Sasaki T, Fan D, Coombes KR, Kim SJ, Fidler IJ