Project description:A better understanding of the consequences of recurrent (epi)genetic alterations that occur during cervical carcinogenesis is essential in the search for novel biomarkers. In this study we determined genome-wide expression profiles of 10 squamous cell carcinomas (SCCs), 5 adenocarcinomas (AdCAs) and 6 normal epithelial samples. Expression patterns were subsequently combined with previously determined chromosomal profiles in the same carcinomas. Differential gene expression analysis identified 76 genes with altered expression in carcinomas compared to normal epithelium. Microarray results for a subset of these genes were validated by real-time RT-PCR. Among the differentially expressed genes a relative overrepresentation of genes located at chromosome 3q, one of the most frequently gained areas in SCCs, was observed (false discovery rate (FDR)<0.005). To further investigate the relationship between gene expression and chromosomal alterations 2 statistical approaches were used, i.e. differential gene locus mapping (DIGMAP) and the array CGH expression integration tool (ACE-it). Using these methods we found that increased gene expression was linked to increased gene copy numbers at 1q32.1, 3q13.32-22.3, 3q26.32-27.3, and 20q11.21-13.33, whereas a loss at 11q22.3-25 correlated with recurrent decreased gene expression. Integrated genome-wide chromosomal and transcriptional analysis of cervical carcinomas highlighted 7 genes (i.e. FLJ21291, DTX3L, CCDC14, MCM2, PIK3R4, ATP2C1 and SLC25A36), which were identified by differential gene expression analysis and were located within the chromosomal regions identified by DIGMAP and/or ACE-it as well. Further investigations of these promising marker genes in warranted. Keywords: microarray analysis, array CGH, cervical cancer For microarray mRNA expression analysis 10 SCCs, 5 AdCAs and 6 normal epithelial controls were used. Normal cervical controls consisted of 1 pool of 3 normal cervices distant from tumour, 1 pool of 4 normal ectocervical smears and 1 pool of 5 normal endocervical smears. To expand our number of normal squamous epithelial controls, we included expression profiles of 3 uvulas of non-cancer patients who underwent uvulopalatopharyngoplasty. In addition, we hybridised RNA isolated from 2 different biopsies of the same SCC (SCC12 and SCC13) as a biological replicate. The pool of 4 normal ectocervical smears was hybridised twice as a technical replicate to determine technical variation. Genomic profiling of the same 10 SCCs and 5 AdCAs was done using array CGH (Wilting et al, J Pathol 2006, volume 209, p 220-30).

Project description:The zinc-finger protein which regulates apoptosis and cell cycle arrest 1 (Zac1), encoded by Plagl1 gene, is a seven-zinc-finger containing transcription factor belonging to the imprinted genome and is expressed in diverse types of embryonic and adult human tissues. Zac1 is postulated to be a tumor suppressor by inducing cell cycle arrest and apoptosis through interacting and modulating transcriptional activity of p53 as it was named. Correspondingly, the reduction or loss of Zac1 expression is associated with the incidence and progression of several human tumors, including cervical cancer, breast cancer, ovarian cancer, pituitary tumors, and basal cell carcinoma, implying the rationality of utilizing Zac1 expression as novel a biomarker for the evaluation of cervical cancer prognosis. However, to date, it has not been elucidated whether Zac1 expression is related to the prognosis of patients in clinical cervical cancer tumor samples. To address the questions outlined above, we report here a comprehensive investigation of Zac1 expression in biopsies of clinical cervical carcinoma. By analyzing Zac1 expression in various gene expression profiling of cervical cancer databases, we show the association between high Zac1 expression and poor prognosis of cervical cancer. Functional enrichment analysis showed that high Zac1 expression was associated with epithelial-mesenchymal transition (EMT), which was further observed in clinical characteristics and metastatic carcinoma samples using immunohistochemical staining. Correspondingly, hypomethylation of CpG island on Zac1 promoter was observed in samples with high Zac1 expression in cervical carcinoma. Finally, overexpression of Zac1 in a variety of cervical cancer cell lines increase their mesenchymal biomarker expression and migration, strengthening the correlation between cervical cancers with high Zac1 expression and metastasis in clinical. In summary, this research firstly revealed that identifying Zac1 expression or the methylation status of CpG site on Zac1 promoter may provide us with novel indicators for the evaluation of cervical cancer metastasis.

Dataset Information

Integrated genomic and transcriptional profiling identifies chromosomal loci with altered gene expression in cervical cancer.

Publications

Integrated genomic and transcriptional profiling identifies chromosomal loci with altered gene expression in cervical cancer.

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