TY - JOUR
T1 - Microrna-dependent regulation of DNA methyltransferase-1 and tumor suppressor gene expression by interleukin-6 in human malignant cholangiocytes
AU - Braconi, Chiara
AU - Huang, Nianyuan
AU - Patel, Tushar
PY - 2010/3
Y1 - 2010/3
N2 - Although the inflammation-associated cytokine interleukin-6 (IL-6) has been implicated in cholangiocarcinoma growth, the relationship between IL-6 and oncogenic changes is unknown. IL-6 can increase expression of DNA methyltransferase-1 (DNMT-1) and epigenetically regulate the expression of several genes, including microRNAs (miRNAs). DNMT-1 up-regulation occurs in hepatobiliary cancers and is associated with a poor prognosis. To understand the potential regulation of DNMT-1 by IL-6-dependent miRNAs, we examined the expression of a group of miRNAs which have sequence complementarity to the 3'-untranslated region of DNMT-1, namely miR-148a, miR-152, and miR-301. The expression of these miRNAs was decreased in cholangiocarcinoma cells. Moreover, the expression of all three miRNAs was decreased in IL-6-overexpressing malignant cholangiocytes in vitro and in tumor cell xenografts. There was a concomitant decrease in expression of the methylationsensitive tumor suppressor genes Rassf1a and p16INK4a. Using luciferase reporter constructs, DNMT-1 was verified as a target for miR-148a and miR-152. Precursors to miR-148a and miR-152 decreased DNMT-1 protein expression, increased Rassf1a and p16INK4a expression, and reduced cell proliferation. Conclusion: These data indicate that IL-6 can regulate the activity of DNMT-1 and expression of methylation- dependent tumor suppressor genes by modulation of miR-148a and miR-152, and provide a link between this inflammation-associated cytokine and oncogenesis in cholangiocarcinoma.
AB - Although the inflammation-associated cytokine interleukin-6 (IL-6) has been implicated in cholangiocarcinoma growth, the relationship between IL-6 and oncogenic changes is unknown. IL-6 can increase expression of DNA methyltransferase-1 (DNMT-1) and epigenetically regulate the expression of several genes, including microRNAs (miRNAs). DNMT-1 up-regulation occurs in hepatobiliary cancers and is associated with a poor prognosis. To understand the potential regulation of DNMT-1 by IL-6-dependent miRNAs, we examined the expression of a group of miRNAs which have sequence complementarity to the 3'-untranslated region of DNMT-1, namely miR-148a, miR-152, and miR-301. The expression of these miRNAs was decreased in cholangiocarcinoma cells. Moreover, the expression of all three miRNAs was decreased in IL-6-overexpressing malignant cholangiocytes in vitro and in tumor cell xenografts. There was a concomitant decrease in expression of the methylationsensitive tumor suppressor genes Rassf1a and p16INK4a. Using luciferase reporter constructs, DNMT-1 was verified as a target for miR-148a and miR-152. Precursors to miR-148a and miR-152 decreased DNMT-1 protein expression, increased Rassf1a and p16INK4a expression, and reduced cell proliferation. Conclusion: These data indicate that IL-6 can regulate the activity of DNMT-1 and expression of methylation- dependent tumor suppressor genes by modulation of miR-148a and miR-152, and provide a link between this inflammation-associated cytokine and oncogenesis in cholangiocarcinoma.
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U2 - 10.1002/hep.23381
DO - 10.1002/hep.23381
M3 - Article
C2 - 20146264
AN - SCOPUS:77950600443
SN - 0270-9139
VL - 51
SP - 881
EP - 890
JO - Hepatology
JF - Hepatology
IS - 3
ER -