Improvement of tissue preparation for laser capture microdissection: application for cell type-specific miRNA expression profiling in colorectal tumorsReport as inadecuate




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BMC Genomics

, 11:163

First Online: 10 March 2010Received: 01 November 2009Accepted: 10 March 2010

Abstract

BackgroundLaser capture microdissection LCM has successfully isolated pure cell populations from tissue sections and the combination of LCM with standard genomic and proteomic methods has revolutionized molecular analysis of complex tissue. However, the quantity and quality of material recovered after LCM is often still limited for analysis by using whole genomic and proteomic approaches. To procure high quality and quantity of RNA after LCM, we optimized the procedures on tissue preparations and applied the approach for cell type-specific miRNA expression profiling in colorectal tumors.

ResultsWe found that the ethanol fixation of tissue sections for 2 hours had the maximum improvement of RNA quality 1.8 fold, p = 0.0014 and quantity 1.5 fold, p = 0.066. Overall, the quality RNA integrity number, RIN for the microdissected colorectal tissues was 5.2 ± 1.5 average ± SD for normal n = 43, 5.7 ± 1.1 for adenomas n = 14 and 7.2 ± 1.2 for carcinomas n = 44. We then compared miRNA expression profiles of 18 colorectal tissues 6 normal, 6 adenomas and 6 carcinomas between LCM selected epithelial cells versus stromal cells using Agilent miRNA microarrays. We identified 51 differentially expressed miRNAs p <= 0.001 between these two cell types. We found that the miRNAs in the epithelial cells could differentiate adenomas from normal and carcinomas. However, the miRNAs in the stromal and mixed cells could not separate adenomas from normal tissues. Finally, we applied quantitative RT-PCR to cross-verify the expression patterns of 7 different miRNAs using 8 LCM-selected epithelial cells and found the excellent correlation of the fold changes between the two platforms R = 0.996.

ConclusionsOur study demonstrates the feasibility and potential power of discovering cell type-specific miRNA biomarkers in complex tissue using combination of LCM with genome-wide miRNA analysis.

Electronic supplementary materialThe online version of this article doi:10.1186-1471-2164-11-163 contains supplementary material, which is available to authorized users.

Shuyang Wang, Lei Wang contributed equally to this work.

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Author: Shuyang Wang - Lei Wang - Tengfang Zhu - Xue Gao - Jian Li - Ying Wu - Hongguang Zhu

Source: https://link.springer.com/article/10.1186/1471-2164-11-163







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