Clinically Relevant microRNAs in Ovarian Cancer
MOLECULAR CANCER RESEARCH
Authors: Zhang, Shu; Lu, Zhen; Unruh, Anna K.; Ivan, Cristina; Baggerly, Keith A.; Calin, George A.; Li, Zongfang; Bast, Robert C., Jr.; Le, Xiao-Feng
Abstract
microRNAs (miRNAs/miRs) belong to a class of small noncoding RNAs that can negatively regulate messenger RNA (mRNA) expression of target genes. miRNAs are involved in multiple aspects of ovarian cancer cell dysfunction and the phenotype of ovarian cancer cells can be modified by targeting miRNA expression. miRNA profiling has detected a number of candidate miRNAs with the potential to regulate many important biologic functions in ovarian cancer, but their role still needs to be clarified, given the remarkable heterogeneity among ovarian cancers and the context dependent role of miRNAs. This review summarizes the data collected from The Cancer Genome Atlas (TCGA) and several other genome-wide projects to identify dysregulated miRNAs in ovarian cancers. Copy number variations (CNVs), epigenetic alterations, and oncogenic mutations are also discussed that affect miRNA levels in ovarian disease. Emphasis is given to the role of particular miRNAs in altering expression of genes in human ovarian cancers with the potential to provide diagnostic, prognostic, and therapeutic targets. Particular attention has been given to TP53, BRCA1/2, CA125 (MUC16), HE4 (WFDC2), and imprinted genes such as ARHI (DIRAS3). A better understanding of the abnormalities in miRNA expression and downstream transcriptional and biologic consequences will provide leads for more effective biomarkers and translational approaches in the management of ovarian cancer. (C) 2014 AACR.
The putative ovarian tumour marker gene HE4 (WFDC2), is expressed in normal tissues and undergoes complex alternative splicing to yield multiple protein isoforms
ONCOGENE
Authors: Bingle, L; Singleton, V; Bingle, CD
Abstract
The whey acidic protein (WAP) domain is a conserved motif, containing eight cysteines found in a characteristic 4-disulphide core arrangement, that is present in a number of otherwise unrelated proteins. WAP motifs are present in SLPI and elafin, two antiproteinases located on chromosome 20q12-13, in a locus rich in poorly characterized WAP domain proteins. One of these proteins, which contains two WAP domains, is HE4 (also known as WFDC2), originally described as an epididymis specific protein but more recently suggested to be a putative serum tumour marker for ovarian cancer. We have shown that HE4 is expressed in a number of normal human tissues outside of the mate reproductive system, including regions of the respiratory tract and nasopharynx, as well as in a subset of lung tumour cell lines. Comparison of multiple HE4 cDNAs and RT-PCR products with genomic sequence allowed the elucidation of the genomic organization. These studies revealed that HE4 can undergo a complex series of alternative splicing events that can potentially yield five distinct WAP domain containing protein isoforms. These results cast doubt on the potential role of HE4 as a serum tumour marker specific for ovarian cancer and open the door to understanding the function of multiple WAP domain containing protein isoforms arising from a single gene.