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Changes in the Circular RNA Transcriptome During Inorganic Arsenic‐Induced Epithelial‐to‐Mesenchymal Transition
Author(s) -
Eleazer Rebekah,
Andreeva Kalina,
FondufeMittendorf Yvonne
Publication year - 2019
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2019.33.1_supplement.623.1
Subject(s) - epigenetics , carcinogenesis , transcriptome , biology , epithelial–mesenchymal transition , epigenome , circular rna , gene expression , microbiology and biotechnology , gene , biogenesis , microrna , gene isoform , 5 hydroxymethylcytosine , rna , genetics , computational biology , transition (genetics) , dna methylation
Inorganic arsenic (iAs) found in the environment is associated with diseases such as cancer. Chronic, low dose exposure to iAs induces cellular transformation and epithelial‐to‐mesenchymal transition (EMT), a hallmark of metastasis. Since iAs is not genotoxic, we hypothesize that iAs drives carcinogenesis by altering gene expression though epigenetic mechanisms. One class of epigenetic gene regulators recently discovered are circular RNAs (circRNAs), which are covalently closed and highly stable isoforms derived from precursor messenger RNAs (mRNAs). They are generated from actively transcribed genes and their biogenesis competes with that of mRNA. circRNAs are highly conserved across eukaryotes however the function of this new class of regulators is still unclear. Our lab and others have shown alterations to the epigenome as driving iAs‐mediated carcinogenesis. However the relevance of the expression of circRNAs in this process is not understood. Interestingly, our preliminary data suggest that circRNAs are differentially expressed during this process. We therefore aim to identify and profile the changes in circRNA expression that occur during iAs‐induced EMT. We have treated BEAS‐2B cells with iAs over a time‐course, measuring changes in EMT‐markers over time. We already have shown that cells move from pre‐EMT to mid EMT to late‐EMT and finally back through MET during iAs‐mediated carcinogenesis. This model was used to profile differential expression of circRNAs. To accomplish this, total RNA was isolated and enriched for circRNAs with an RNase R digest. For gene‐specific analyses, divergent primers designed to amplify across the circRNA backsplice junctions were used in reverse transcription quantitative polymerase chain reaction to identify differentially expressed circRNA transcripts. In our preliminary gene‐specific approach, we have identified a circRNA containing the 3′ untranslated region of neural cell adhesion molecule 2 (NCAM2) in BEAS‐2B cells. NCAM2 is a cell‐to‐cell adhesion molecule involved in neuronal growth and migration, and is known to be upregulated during EMT. We observed that during iAs‐mediated EMT, while the expression of the linear NCAM2 transcript increased, there was a concurrent decrease in the expression of the 3′ untranslated region. These results indicate that circRNA expression is altered during iAs‐induced EMT and suggests that iAs promotes carcinogenesis by altering steady state competition between linear and circular RNA production. We are currently using next generation sequencing to fully profile the circRNA transcriptome as cells undergo iAs‐induced EMT to gain a broader understanding of the functional significance of circRNA in iAs‐induced EMT. Support or Funding Information This work was supported by NIEHS grant (R01‐ES024478). This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .