title: Characterization of novel antisense HIF-1α transcripts in human cancers.
abstract: Whole transcriptome analyses have revealed new classes of long ncRNA (lncRNA), the functions of which are however largely unknown. Recently, we showed that the antitumor DNA topoisomerase I (Top1) inhibitor camptothecin (CPT) increases the cellular levels of two antisense lncRNAs at the 5' (5'aHIF-1α) and 3' (3'aHIF-1α) ends of the human HIF-1α gene. To gain insights into their functions, we have here determined structural and functional aspects of the two antisense RNAs in human cancer cell lines and kidney tumor specimen. We found that the antisense transcripts are activated in response to partially different kinds of stress, and that the 5'aHIF-1α has a 5'Cap and a poly(A+) tail, while the 3'aHIF-1α is known to lack both modifications. Cell fractionation experiments showed that 5' and 3' antisense RNAs are nuclear transcripts. Further analyses by RNA-FISH showed that the 5'aHIF-1α accumulates at the perinuclear cellular compartment and co-localizes with the nuclear pore complex Nup62 protein, suggesting a role in nuclear membrane trafficking. Finally, we provide evidence that the studied antisense lncRNAs are expressed in human kidney cancer tissues, highlighting their possible roles in cancer development. Altogether, our findings may suggest a novel function of 5'aHIF-1α in membrane transport that may regulate the cancer-relevant HIF-1α pathway.
authors: Department of Biochemistry G. Moruzzi, University of Bologna, Bologna, Italy.
authors: Davide
authors: D
authors: Bertozzi
authors: Raffaella
authors: R
authors: Iurlaro
authors: Olivier
authors: O
authors: Sordet
authors: Jessica
authors: J
authors: Marinello
authors: Nadia
authors: N
authors: Zaffaroni
authors: Giovanni
authors: G
authors: Capranico
mesh_terms: D002166:Camptothecin / Q000494:pharmacology; D002458:Cell Fractionation; D003001:Cloning, Molecular; D003676:Deferoxamine / Q000494:pharmacology; D005260:Female; D005455:Fluorescent Antibody Technique; D015972:Gene Expression Regulation, Neoplastic; D045325:HCT116 Cells; D006367:HeLa Cells; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000235:genetics / Q000378:metabolism*; D017404:In Situ Hybridization, Fluorescence / Q000379:methods; D007680:Kidney Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D008297:Male; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism; D060787:Neoplasm Grading; D009685:Nuclear Envelope / Q000235:genetics / Q000378:metabolism; D028861:Nuclear Pore Complex Proteins / Q000235:genetics / Q000378:metabolism; D016372:RNA, Antisense / Q000235:genetics / Q000378:metabolism*; D022661:RNA, Untranslated / Q000235:genetics / Q000378:metabolism; D015533:Transcriptional Activation
chemical_list: C497442:HIF1A protein, human; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D008562:Membrane Glycoproteins; D028861:Nuclear Pore Complex Proteins; D016372:RNA, Antisense; D022661:RNA, Untranslated; C049312:nuclear pore protein p62; D003676:Deferoxamine; D002166:Camptothecin