The knockdown of H19lncRNA reveals its regulatory role in pluripotency and tumorigenesis of human embryonic carcinoma cells

Abstract

The function of imprinted H19 long non-coding RNA is still controversial. It is highly expressed in early embryogenesis and decreases after birth and re-expressed in cancer. To study the role of H19 in oncogenesis and pluripotency, we down-regulated H19 expression in vitro and in vivo in pluripotent human embryonic carcinoma (hEC) and embryonic stem (hES) cells. H19 knockdown resulted in a decrease in the expression of the pluripotency markers Oct4, Nanog, TRA-1-60 and TRA-1-81, and in the up-regulation of SSEA1; it further attenuated cell proliferation, decreased cell-matrix attachment, and up-regulated E-Cadherin expression. SCID-Beige mice transplanted with H19 down-regulated hEC cells exhibited slower kinetics of tumor formation, resulting in an increased animal survival. Tumors derived from H19 down-regulated cells showed a decrease in the expression of pluripotency markers and up-regulation of SSEA-1 and E-cadherin. Our results suggest that H19 oncogenicity in hEC cells is mediated through the regulation of the pluripotency state.

The DLK1-MEG3 locus in malignant cells of proposed primordial germ cell origins.

“…As previously stated, the expression of ncRNAs from these loci maintains HSC stemness and numbers, and the lncRNA H19 preserves the stemness of EC cells [5,6,18]. Similarly, deletion of the H19 gene on the maternal chromosome results in larger teratomas, which are composed of tissues derived from differentiated EC cells [19].…”

“…This would be surprising given that the IGF2-H19 locus is responsible for the quiescence of HSCs and that maternal H19 deletion promotes the growth of teratomas. However, the role of H19 in maintaining the expression of pluripotency markers in EC cells, which may be the stem cell responsible for certain types of GCTs ( Figure 5C), suggests that this imprinting pattern may be important for GCT development [18,43].…”

“…Interestingly, the expression dynamics observed in cells from tumor bulk and low-passage cell lines has also been observed in an established cell line, questioning the usefulness of these cells in tumor models [74]. imprinted genes is related to this phenomenon [18,43].…”

“…For PGCs, hypomethylation of the IGF2-H19 ICR as a result of their epigenetic reprogramming serves not only as an artifact of the putative PGC origins of GCTs, but it is likely an important factor in the malignant transformation of these otherwise benign cells as well [18,[36][37][38]. Similarly, imprinted genes are key regulators of HSC quiescence and maintenance, and several studies have documented various genomic imprinting defects in certain blood disorders [5,6,94].…”

“…Chief among these associations identified thus far is hypomethylation at the IGF2-H19 locus [36][37][38]. While the participation of growth factors such as IGF2 in insulin-like signaling has been implicated in TGCT development, a recent study found the H19 lncRNA to be necessary for the maintenance of EC stem-like cells [18,119].…”