Gene Expression Profiling of the Tumor Microenvironment during Non Small Cell Lung Carcinoma (NSCLC) Progression
V Hofman, M Ilie, C Butori, E Selva, JM Vignaud, F Thivolet, N Venissac, J Mouroux, E Brambilla, P Barbry, B Mari, P Hofman. CHU, Nice, France; CHU, Nancy, France; CHU, Lyon, France; CHU, Grenoble, France; CNRS UMR6097, Nice, France
Background: Genes involved in tumor-microenvironment interactions may provide novel targets for diagnostic development and therapeutic strategy. Our understanding of the interactions between epithelial and stromal components of NSCLC, however, remains limited at the molecular level. We conducted in this study a comparative analysis of global gene expression in the stromal compartiments of NSCLC and healthy lung tissues.
Design: We combined laser capture microdissection (LCM) and gene expression microarrays to analyze 18 patient-matched normal stroma and tumor-associated stroma frozen specimens. Briefly, highly enriched populations of normal stroma (from peribronchial areas) and tumor-associated stroma were procured by LCM using a PixCell II system (Molecular Devices, USA). Total RNA was isolated from captured cells, amplified, labeled and hybridized to whole genome arrays containing 25.484 distinct oligonucleotide probes covering most of the known human transcripts (list of probes available at http://www.microarray.fr). Data were processed using the Bioconductor package with default parameters for back ground correction, quantile normalization and signal summation. Differential gene expression analyses were performed using linear regression models in the limma package. TaqMan real time PCR was performed on amplified RNA used for microarray analysis.
Results: Highly upregulated genes in the tumor-associated stroma include constituents of the matrix metalloproteases and extracellular matrix, cell-cycle-related genes, and different receptors. Among the top100 genes differentially expressed in the tumor associated stroma, MMP11, MMP7, SPARC, STAT3, semaphorin 3B, decorin, a2 smooth muscle actin, VEGF, CXCL9, fibronectin 1 were particularly upregulated in comparison to the level in normal matched stromal tissues.
Conclusions: The present study provides the first comparative analysis of the in situ gene expression profiles of patient-matched normal stroma and stromal compartments of invasive stages of NSCLC. This study supports the view that the tumor microenvironment is an important co-conspirator rather than a passive bystander during tumorigenesis. Moreover, molecular alterations within the stroma offer novel avenues for therapeutic strategies and disease prognosis
Tuesday, March 23, 2010 1:45 PM
Platform Session: Section F, Tuesday Afternoon