TY - JOUR
T1 - MicroRNA (miR)-433 and miR-22 dysregulations induce histone-deacetylase-6 overexpression and ciliary loss in cholangiocarcinoma
AU - Mansini, Adrian P.
AU - Lorenzo Pisarello, Maria J.
AU - Thelen, Kristen M.
AU - Cruz-Reyes, Maetzin
AU - Peixoto, Estanislao
AU - Jin, Sujeong
AU - Howard, Brynn N.
AU - Trussoni, Christy E.
AU - Gajdos, Gabriella B.
AU - LaRusso, Nicholas F.
AU - Perugorria, Maria J.
AU - Banales, Jesus M.
AU - Gradilone, Sergio A.
N1 - Publisher Copyright:
© 2018 by the American Association for the Study of Liver Diseases.
PY - 2018/8
Y1 - 2018/8
N2 - Cholangiocytes normally express primary cilia, a multisensory organelle that detects signals from the cellular environment. Cilia are significantly reduced in cholangiocarcinoma (CCA) by a mechanism involving overexpression of histone deacetylase 6 (HDAC6). Despite HDAC6 overexpression in CCA, we found no differences in its mRNA level, suggesting a posttranscriptional regulation, possibly involving microRNAs (miRNAs). Here, we describe that at least two HDAC6-targeting miRNAs, miR-433 and miR-22, are down-regulated in CCA both in vitro and in vivo. Experimental restoration of these miRNAs in CCA cells reduced HDAC6 expression, induced ciliary restoration, and decreased the malignant phenotype. Furthermore, in contrast to the mature forms, levels of precursor forms of these miRNAs were higher in CCA compared to normal cholangiocytes and accumulated in the nuclei, suggesting a defective nuclear export. We assessed the expression of Exportin-5, the protein responsible for transporting miRNA precursors out of the nucleus, and found it to be reduced by 50% in CCA compared to normal cholangiocytes. Experimental overexpression of Exportin-5 in CCA cells restored precursor and mature forms of these miRNAs to normal levels, inducing a decrease in the expression of HDAC6 and a decrease in the malignant phenotype. Conversely, short hairpin RNA (shRNA) depletion of Exportin-5 in normal cholangiocytes resulted in increased nuclear retention of precursor miRNAs, decreased mature miRNAs, increased cell proliferation, and shorter cilia. Conclusion: These data suggest that down-regulated Exportin-5 impairs the nuclear export of miR-433 and miR-22 precursor forms, causing a decrease in levels of mature miR-433 and miR-22 forms, and leading to overexpression of HDAC6 and ciliary loss in CCA. (Hepatology 2018).
AB - Cholangiocytes normally express primary cilia, a multisensory organelle that detects signals from the cellular environment. Cilia are significantly reduced in cholangiocarcinoma (CCA) by a mechanism involving overexpression of histone deacetylase 6 (HDAC6). Despite HDAC6 overexpression in CCA, we found no differences in its mRNA level, suggesting a posttranscriptional regulation, possibly involving microRNAs (miRNAs). Here, we describe that at least two HDAC6-targeting miRNAs, miR-433 and miR-22, are down-regulated in CCA both in vitro and in vivo. Experimental restoration of these miRNAs in CCA cells reduced HDAC6 expression, induced ciliary restoration, and decreased the malignant phenotype. Furthermore, in contrast to the mature forms, levels of precursor forms of these miRNAs were higher in CCA compared to normal cholangiocytes and accumulated in the nuclei, suggesting a defective nuclear export. We assessed the expression of Exportin-5, the protein responsible for transporting miRNA precursors out of the nucleus, and found it to be reduced by 50% in CCA compared to normal cholangiocytes. Experimental overexpression of Exportin-5 in CCA cells restored precursor and mature forms of these miRNAs to normal levels, inducing a decrease in the expression of HDAC6 and a decrease in the malignant phenotype. Conversely, short hairpin RNA (shRNA) depletion of Exportin-5 in normal cholangiocytes resulted in increased nuclear retention of precursor miRNAs, decreased mature miRNAs, increased cell proliferation, and shorter cilia. Conclusion: These data suggest that down-regulated Exportin-5 impairs the nuclear export of miR-433 and miR-22 precursor forms, causing a decrease in levels of mature miR-433 and miR-22 forms, and leading to overexpression of HDAC6 and ciliary loss in CCA. (Hepatology 2018).
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U2 - 10.1002/hep.29832
DO - 10.1002/hep.29832
M3 - Article
C2 - 29406621
AN - SCOPUS:85051418274
SN - 0270-9139
VL - 68
SP - 561
EP - 573
JO - Hepatology
JF - Hepatology
IS - 2
ER -