H19 mRNA-like Noncoding RNA Promotes Breast Cancer Cell Proliferation through Positive Control by E2F1

Abstract

The imprinted H19 gene has riboregulatory functions. We show here that H19 transcription is up-regulated during the S-phase of growth-stimulated cells and that the H19 promoter is activated by E2F1 in breast cancer cells. H19 repression by pRb and E2F6 confirms the E2F1-dependent control of the H19 promoter. Consistently, we demonstrate by chromatin immunoprecipitation assays that endogenous E2F1 is recruited to the H19 promoter in vivo. The functionality of E2F promoter sites was further confirmed by gel shift and mutagenesis experiments, revealing that these sites are required for binding and promoter response to E2F1 exogenous expression and serum stimulation. Furthermore, we show that H19 overexpression confers a growth advantage on breast cancer cells released from growth arrest as well as in asynchronously growing cells. The H19 knockdown by small interfering RNA duplexes impedes S-phase entry in both wild-type and stably H19-transfected cells. Based on these findings, we conclude that the H19 RNA is actively linked to E2F1 to promote cell cycle progression of breast cancer cells. This clearly supports the H19 oncogenic function in breast tumor genesis.

Analysis of the miRNA–mRNA–lncRNA networks in ER+ and ER− breast cancer cell lines

“…Generally, based on the position of the lncRNA relative to the neighbouring protein‐coding genes in the genome, lncRNAs can be divided into five categories, namely: sense, antisense, bidirectional, intronic and intergenic 7. Although lncRNAs have been investigated less often than miRNAs, a number of lncRNAs have been functionally characterized, such as HOTAIR 8, 9, Xist 10 and H19 11, 12, 13. Recent reports have shown that lncRNAs are involved in the regulatory roles in diverse processes, such as imprinting, X‐inactivation and development.…”

Aflatoxin B1 Promotes Cell Growth and Invasion in Hepatocellular Carcinoma HepG2 Cells through H19 and E2F1

“…As described in the study of Berteaux and his partners (Berteaux et al, 2005), the binding site of E2F1 was found on the promoter of H19. To confirm the relationship of E2F1 and H19 in hepatocellular carcinoma HepG2 cells, ChIP was carried out and the H19 gene in protein-DNA complexes was detected by qPCR.…”

“…The previous study has shown that over-expression of an ectopic H19 gene enhances the tumorigenic properties of breast cancer cells (Lottin et al, 2002). In addition, the expression of H19 is positively controlled by E2F1 and suppressed by p53 (Dugimont et al, 1998;Berteaux et al, 2005). Although we have known the respective roles of AFB1 and H19, the relationship between them is not known so far.…”

“…The siRNA sequence of E2F1 is as follows: 5'-GGGAGAAGUCACGCUAUGA-3' (Berteaux et al, 2005). The open reading frame of E2F1 (NM_005225) was cloned and inserted into expression plasmid pcDNA3.1.…”

The long non-coding RNAs, a new cancer diagnostic and therapeutic gold mine

“…Loss of imprinting at the H19 locus resulted in high H19 expression in cancers of the esophagus, choricarcinoma, liver, breast, bladder and with hepatic metastases. [51][52][53][54][55] The product of the MYC oncogene is widely deregulated in cancer and functions as a regulator of gene transcription. c-Myc significantly induces the expression of the H19 lncRNA in diverse cell types, including breast epithelial, glioblastoma and fibroblast cells.…”