Endocrinology

Here, the gene expression profiles of EHEC O157:H7 and HT-29 during the attachment stage were investigated by using duplex whole transcriptome analysis. After the initial attachment (3 h), the gene regulation systems of both the EHEC O157:H7 and HT-29 host cells were immediately remodeled. A total of 326 genes of the HT-29 cells, which involved proteins associated with the detoxification process, stress response proteins, anti-apoptosis/inflammation proteins, immune response protein, and oxidative stress proteins, were differentially regulated by more than 2.0-fold during EHEC attachment. In contrast, when HT-29 was attached to EHEC the expression of 611 genes was induced and the expression of 384 genes was reduced by more than twofold when compared to RPMI 1640-grown EHEC (16.14% of the total hybridized genes). Among the genes that were classified according to biological function, the mRNA levels of the genes involved in stress response, oxidative stress, cell signaling and cell surface proteins were significantly altered after the attachment of EHEC O157:H7. Therefore, the results of this study provide crucial insight into the genetic networks that provide host cell protection and the strategy of EHEC O157:H7 pathogenesis in gastro-intestinal (GI) tracts.

Recently, microarray-based comparative genomic hybridization (array-CGH) has emerged as a very efficient technology with higher resolution for the genome-wide identification of copy number alterations (CNA). Although CNAs are thought to affect gene expression, there is no platform currently available for the integrated CNA-expression analysis. To achieve high-resolution copy number analysis integrated with expression profiles, we established human 30k oligoarray-based genome-wide copy number analysis system and explored the applicability of this system for integrated genome and transcriptome analysis using MDA-MB-231 cell line. We compared the CNAs detected by the oligoarray with those detected by the 3k BAC array for validation. The oligoarray identified the single copy difference more accurately and sensitively than the BAC array. Seventeen CNAs detected by both platforms in MDA-MB-231 such as gains of 5p15.33-13.1, 8q11.22-8q21.13, 17p11.2, and losses of 1p32.3, 8p23.3-8p11.21, and 9p21 were consistently identified in previous studies on breast cancer. There were 122 other small CNAs (mean size 1.79 mb) that were detected by oligoarray only, not by BAC-array. We performed genomic qPCR targeting 7 CNA regions, detected by oligoarray only, and one non-CNA region to validate the oligoarray CNA detection. All qPCR results were consistent with the oligoarray-CGH results. When we explored the possibility of combined interpretation of both DNA copy number and RNA expression profiles, mean DNA copy number and RNA expression levels showed a significant correlation. In conclusion, this 30k oligoarray-CGH system can be a reasonable choice for analyzing whole genome CNAs and RNA expression profiles at a lower cost.