MicroRNA Expression and Regulation in Human Ovarian Carcinoma Cells by Luteinizing Hormone

Abstract

BackgroundMicroRNAs have been widely-studied with regard to their aberrant expression and high correlation with tumorigenesis and progression in various solid tumors. With the major goal of assessing gonadotropin (luteinizing hormone, LH) contributions to LH receptor (LHR)-positive ovarian cancer cells, we have conducted a genome-wide transcriptomic analysis on human epithelial ovarian cancer cells to identify the microRNA-associated cellular response to LH-mediated activation of LHR.MethodsHuman ovarian cancer cells (SKOV3) were chosen as negative control (LHR−) and stably transfected to express functional LHR (LHR+), followed by incubation with LH (0–20 h). At different times of LH-mediated activation of LHR the cancer cells were analyzed by a high-density Ovarian Cancer Disease-Specific-Array (DSA, ALMAC™), which profiled ∼100,000 transcripts with ∼400 non-coding microRNAs.FindingsIn total, 65 microRNAs were identified to exhibit differential expression in either LHR expressing SKOV3 cells or LH-treated cells, a few of which have been found in the genomic fragile regions that are associated with abnormal deletion or amplification in cancer, such as miR-21, miR-101-1, miR-210 and miR-301a. By incorporating the dramatic expression changes observed in mRNAs, strong microRNA/mRNA regulatory pairs were predicted through statistical analyses coupled with collective computational prediction. The role of each microRNA was then determined through a functional analysis based on the highly-confident microRNA/mRNA pairs.ConclusionThe overall impact on the transcriptome-level expression indicates that LH may regulate apoptosis and cell growth of LHR+ SKOV3 cells, particularly by reducing cancer cell proliferation, with some microRNAs involved in regulatory roles.

MicroRNA-101 Inhibits Cell Proliferation, Invasion, and Promotes Apoptosis by Regulating Cyclooxygenase-2 in Hela Cervical Carcinoma Cells

“…MicroRNAs (miRNAs) are a group of endogenously expressed, non-coding small RNAs (20-25 nucleotides in length) known to negatively regulate gene expression by suppressing translation or decreasing the stability of mRNAs by directly binding to the 3'-untranslated region (3'-UTRs) of target mRNAs (Dykxhoorn, 2010;Cui et al, 2011). Functional studies indicate that miRNAs are important to several fundamental biological processes, including proliferation, apoptosis, development, and cellular differentiation (Bumgarner et al, 2009;Yu et al, 2010).…”

Transcriptomic Analysis of Human Ovarian Cancer Cells: Changes Mediated by Luteinizing Hormone Receptor Activation

“…In a parallel study on microRNA expression, the ovarian cancer DSA TM array (Almac Diagnostics) was used (Cui et al, 2011b). The advantages in using ovarian cancer-specific arrays include the gathering of extensive amounts of novel mRNA data that are not covered by other platforms and putting both microRNA and mRNA probes on the same chips, hence avoiding potential noise introduced during data collection on separate chips.…”

“…Many microRNAs are androgen related, and their deregulation is highly correlated with initiation, progression, and prognosis of cancer (Calin et al, 2005;Yanaihara et al, 2006;Bloomston et al, 2007;Ambs et al, 2008;Garzon et al, 2008;Schetter et al, 2008;Croce, 2009;Wyman et al, 2009). Recently, 17 microRNAs were found to be differentially expressed in LHR+ SKOV-3 cells versus control cells (Cui et al, 2011b), specifically: six up-regulated (miR-101-1, -101-2, -199b, -559, -573, and -7-3) and 11 down-regulated (miR-103-2, -200c, 151, 29c, 301b, 548a2, 552, 561, 566, 613, and 642). After incubation with LH, 57 microRNAs were found to be differentially expressed, including the most highly-expressed microRNAs, such as miR-21, -200c, -593, -103-1, and -124-3.…”

“…Collectively, 65 microRNAs have been identified to be differentially expressed in LHR+ SKOV-3 cells versus control. The mRNAs with which the microRNA may interact have been studied in order to infer potentially regulated processes involving the microRNAs (Cui et al, 2011b). Specifically, Spearman correlation analysis was performed between the expression of the 65 differentially-expressed microRNAs and the expression of 60,860 well-annotated mRNAs across all sample groups under consideration, resulting in 62,150 and 931,009 microRNAmRNA pairs with significantly correlated expressions, positive or negative, using cutoffs |rho|>0.8 and P-value <0.05, where rho represents the Spearman correlation coefficient.…”

“…With the above cutoffs, only 155 genes were retained as highly-confident microRNA targets for further analysis. For each of the 65 microRNAs under consideration, its function was predicted through identification of the functions and pathways enriched by their target genes; the functions of 16 differentiallyexpressed microRNAs were so predicted (Cui et al, 2011b). For example, miR-199b-5p is predicted to participate in angiogenesis, nucleotide excision repair, the PDGF signaling pathway, the cadherin/Wnt/integrin signaling pathway, apoptosis, and the MAPK signaling pathway.…”