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BackgroundThe human genome encodes thousands of unique long non-coding RNAs (lncRNAs), and these transcripts are emerging as critical regulators of gene expression and cell fate. However, the transcriptional regulation of their expression is not fully understood. The pivotal transcription factor E2F1 which can induce both proliferation and cell death, is a critical downstream target of the tumor suppressor, RB. The retinoblastoma pathway is often inactivated in human tumors resulting in deregulated E2F activity.ResultsHere, we report that lncRNA XLOC 006942, which we named ERIC, is regulated by E2F1 and, most probably, also E2F3. We show that expression levels of ERIC were elevated upon activation of exogenous E2F1, E2F3 or endogenous E2Fs. Moreover, knockdown of either E2F1 or E2F3 reduced ERIC levels and endogenous E2F1 binds ERIC’s promoter. Expression of ERIC was cell cycle regulated and peaked in G1 in an E2F1-dependent manner. Inhibition of ERIC expression increased E2F1-mediated apoptosis, suggesting that E2F1 and ERIC constitute a negative feedback loop that modulates E2F1 activity. Furthermore, ERIC levels were increased following DNA damage by the chemotherapeutic drug Etoposide, and inhibition of ERIC expression enhanced Etoposide -induced apoptosis.ConclusionsOur data identify ERIC as a novel lncRNA that is transcriptionally regulated by E2Fs, and restricts apoptosis induced by E2F1, as well as by DNA damage.

SummaryAn open question remains in cancer stem cell (CSC) biology whether CSCs are by definition at the top of the differentiation hierarchy of the tumor. Wilms’ tumor (WT), composed of blastema and differentiated renal elements resembling the nephrogenic zone of the developing kidney, is a valuable model for studying this question because early kidney differentiation is well characterized. WT neural cell adhesion molecule 1-positive (NCAM1+) aldehyde dehydrogenase 1-positive (ALDH1+) CSCs have been recently isolated and shown to harbor early renal progenitor traits. Herein, by generating pure blastema WT xenografts, composed solely of cells expressing the renal developmental markers SIX2 and NCAM1, we surprisingly show that sorted ALDH1+ WT CSCs do not correspond to earliest renal stem cells. Rather, gene expression and proteomic comparative analyses disclose a cell type skewed more toward epithelial differentiation than the bulk of the blastema. Thus, WT CSCs are likely to dedifferentiate to propagate WT blastema.

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In recent years, the notion that ovarian carcinoma results from ovulation-induced inflammation of the fallopian tube epithelial cells (FTECs) has gained evidence. However, the mechanistic pathway for this process has not been revealed yet. In the current study, we propose the mutator protein activation-induced cytidine deaminase (AID) as a link between ovulation-induced inflammation in FTECs and genotoxic damage leading to ovarian carcinogenesis. We show that AID, previously shown to be functional only in B lymphocytes, is expressed in FTECs under physiological conditions, and is induced in vitro upon ovulatory-like stimulation and in vivo in carcinoma-associated FTECs. We also report that AID activity results in epigenetic, genetic and genomic damage in FTECs. Overall, our data provides new insights into the etiology of ovarian carcinogenesis and may set the ground for innovative approaches aimed at prevention and early detection.

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BackgroundThe genetic mechanisms underlying hemangioblastoma development are still largely unknown. We used high-resolution single nucleotide polymorphism microarrays and droplet digital PCR analysis to detect copy number variations (CNVs) in total of 45 hemangioblastoma tumors.ResultsWe identified 94 CNVs with a median of 18 CNVs per sample. The most frequently gained regions were on chromosomes 1 (p36.32) and 7 (p11.2). These regions contain the EGFR and PRDM16 genes. Recurrent losses were located at chromosome 12 (q24.13), which includes the gene PTPN11.ConclusionsOur findings provide the first high-resolution genome-wide view of chromosomal changes in hemangioblastoma and identify 23 candidate genes: EGFR, PRDM16, PTPN11, HOXD11, HOXD13, FLT3, PTCH, FGFR1, FOXP1, GPC3, HOXC13, HOXC11, MKL1, CHEK2, IRF4, GPHN, IKZF1, RB1, HOXA9, and micro RNA, such as hsa-mir-196a-2 for hemangioblastoma pathogenesis. Furthermore, our data implicate that cell proliferation and angiogenesis promoting pathways may be involved in the molecular pathogenesis of hemangioblastoma.

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