RGD Reference Report - Benzo[a]pyrene-7,8-diol-9,10-epoxide inhibits gap junction intercellular communication via phosphorylation of tumor progression locus 2 in WB-F344 rat liver epithelial cells. - Rat Genome Database

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Benzo[a]pyrene-7,8-diol-9,10-epoxide inhibits gap junction intercellular communication via phosphorylation of tumor progression locus 2 in WB-F344 rat liver epithelial cells.

Authors: Lee, Bo Kyung  Chung, Min-Yu  Lee, Ki Won 
Citation: Lee BK, etal., Mol Carcinog. 2015 May;54(5):351-8. doi: 10.1002/mc.22103. Epub 2013 Nov 19.
RGD ID: 151356927
Pubmed: PMID:24249418   (View Abstract at PubMed)
DOI: DOI:10.1002/mc.22103   (Journal Full-text)

Benzo[a]pyrene-7,8-diol-9,10-epoxide (B[a]PDE), a major metabolite of benzo[a]pyrene, has been reported to function as a human carcinogen. However, the molecular mechanism of how B[a]PDE regulates signaling pathways during tumor promotion remains unclear. In this study, we investigated the effects of B[a]PDE on the regulation of gap junction intercellular communication (GJIC), one of the major carcinogenic processes, and its main regulatory signaling pathways using WB-F344 rat liver epithelial (WB-F344 RLE) cells. Treatment of benzo[a]pyrene or B[a]PDE resulted in GJIC inhibition, and B[a]PDE was more active at lower concentrations than benzo[a]pyrene in the suppression of GJIC. This suggests that B[a]PDE is a stronger GJIC inhibitor. B[a]PDE at 1 µM reversibly inhibited GJIC in WB-F344 RLE cells, which was attributable to hyperphosphorylation of connexin43 (Cx43) via phosphorylation of mitogen-activated protein kinase/extracellular signal-regulated kinase (MEK) and extracellular signal-regulated kinase (ERK). We found that B[a]PDE induced phosphorylation of tumor progression locus 2 (Tpl2), a direct upstream regulator of MEK. Tpl2 inhibitor recovered B[a]PDE-induced GJIC inhibition and attenuated B[a]PDE-induced MEK/ERK phosphorylation in WB-F344 RLE cells. Collectively, our results suggest that B[a]PDE suppresses GJIC by activating Tpl2 and subsequently the MEK/ERK pathway and Cx43 phosphorylation in WB-F344 RLE cells. These results outline the potential importance of Tpl2 as a novel therapeutic target for B[a]PDE-induced GJIC inhibition during cancer promotion.

Gene Ontology Annotations    Click to see Annotation Detail View

Biological Process
TermQualifierEvidenceWithReferenceNotesSourceOriginal Reference(s)
gap junction-mediated intercellular transport  IMP 151356927 RGD 

Objects Annotated

Genes (Rattus norvegicus)
Map3k8  (mitogen-activated protein kinase kinase kinase 8)


Additional Information