The oncofetal H19 gene transcribes a long non-coding RNA(lncRNA) that is essential for tumor growth. Here we found that numerous established inducers of epithelial to mesenchymal transition(EMT) also induced H19/miR-675 expression. Both TGF-β and hypoxia concomitantly induced H19 and miR-675 with the induction of EMT markers. We identified the PI3K/AKT pathway mediating the inductions of Slug, H19 RNA and miR-675 in response to TGF-β treatment, while Slug induction depended on H19 RNA. In the EMT induced multidrug resistance model, H19 level was also induced. In a mouse breast cancer model, H19 expression was tightly correlated with metastatic potential. In patients, we detected high H19 expression in all common metastatic sites tested, regardless of tumor primary origin. H19 RNA suppressed the expression of E-cadherin protein. H19 up-regulated Slug expression concomitant with the suppression of E-cadherin protein through a mechanism that involved miR-675. Slug also up-regulated H19 expression and activated its promoter. Altogether, these results may support the existence of a positive feedback loop between Slug and H19/miR-675, that regulates E-cadherin expression. H19 RNA enhanced the invasive potential of cancer cells in vitro and enhanced tumor metastasis in vivo. Additionally, H19 knockdown attenuated the scattering and tumorigenic effects of HGF/SF. Our results present novel mechanistic insights into a critical role for H19 RNA in tumor progression and indicate a previously unknown link between H19/miR-675, Slug and E-cadherin in the regulation of cancer cell EMT programs.

The axonal projection mutations irregular chiasm C of Drosophila melanogaster comap and genetically interact with the roughest locus, which is required for programmed cell death in the developing retina. We cloned the genomic region in 3C5 by transposon tagging and identified a single transcription unit that produces a major, spatially and temporally regulated mRNA species of -5.0 kb. Postembryonic expression is strong in the developing optic lobe and in the eye imaginal disc. The gene encodes a transmembrane protein of 764 amino acids with five extracellular immunoglobulin-like domains and similarity to the chicken axonal surface glycoprotein DM-GRASP/SC1/BEN. Both known irreC alleles reduce the level of transcription, whereas the roughest cT mutation disrupts the intracellular domain of the protein.[Key Words: Cell adhesion; Immunoglobulin superfamily; DM-GRASP; optic chiasms; structural brain mutant; verticals]Received August 19, 1993; revised version accepted September 27, 1993.The assembly of a functional nervous system requires the numerical matching and precise connection of neuronal populations, which are often spatially distant. This is achieved through the remarkable ability of developing axons specifically to find and follow the pathways leading to their synaptic targets (for review, see Bixby and Harris 1991;Doherty and Walsh 1992;Hynes and Lander 1992) and through the degeneration of surplus cells (Hollyday and Hamburger 1976;Katz and Lasek 1978). The elucidation of the molecular mechanisms responsible for axonal guidance, neural recognition, and the triggering of cell death is therefore essential to an understanding of the basic developmental strategies generating the intricate pattern of neural organization seen in the adult.In the past few years several studies have provided new insights into the cellular and molecular cues required for correct axonal pathfinding. These include the molecular cloning and characterization of a number of cell surface Present addresses: tlnstituto

The product of the imprinted oncofetal H19 gene is an untranslated RNA of unknown function. With the human cDNA Atlas microarray, we detected differentially expressed genes modulated by the presence of H19 RNA. Many of the genes that are upregulated by H19 RNA are known to contribute to the invasive, migratory, and angiogenic capacities of cells. Moreover, we provided experimental data indicating that whereas H19 RNA did not have any growth advantage for the cells when cultured in 10% fetal calf serum, it did confer an advantage when cells were cultured in serum-poor medium. This observation can be explained in part by the inability of the H19-expressing cells to induce the cyclin-dependent kinase inhibitor p57(kip2) in response to serum stress. Our results favor the possible role of the H19 gene in promoting cancer progression, angiogenesis, and metastasis.

Aims/Background-To study the expression of the H19 gene in hepatocellular carcinoma. H19 is an imprinted, maternally expressed gene, which is tightly linked, both physically and functionally, to the paternally expressed insulin-like growth factor 2 (IGF II). IGF II is known to be involved in liver carcinogenesis. H19 was first discovered in the fetal mouse liver to be under the same regulatory genes as fetoprotein ( FP), a widely used tumour marker for hepatocellular carcinoma. Methods-Using both radioactive and non-radioactive in situ hybridisation, the expression of the H19 gene was compared with the presence of FP, as demonstrated by immunohistochemistry, in 18 cases of hepatocellular carcinoma. Results-H19 expression was present in 13 of 18 cases, whereas staining for FP was positive in only nine of 18 cases. Concordance was found in 12 of 18 tumours (66.7%). In general, the staining pattern for H19 was more diVuse than the immunohistochemical staining for FP. Conclusions-The addition of a nonradioactive in situ hybridisation assay for H19 RNA to the panel of tumour markers used for the histopathological and cytological diagnosis of hepatocellular carcinoma might be useful. (J Clin Pathol:Mol Pathol 1998;51:21-25)

It has only recemiy ~¢omc clear that genetic imprinting pla~ an important role in human cmbwogcnefis and in proccsr~ leading to the development of pediatric cancers and other haman discuss. Osin8 a uniqu~ human ti~ue, the andro~netic complete hydatidiform mole. we cstablishc.d that the maternally inherited allele of the imprinted H 19 8¢ne is espr~sc.d. Our f~ults al~ show that the paternal allele of the haman IGF-II 8en¢. a gear suspected to ~ parentally imprinted in humans, is expre~d.