Dataset Information

Protein kinase CK2 activation is required for transforming growth factor β-induced epithelial-mesenchymal transition.

ABSTRACT: Transforming growth factor β (TGFβ) is overexpressed in advanced cancers and promotes tumorigenesis by inducing epithelial-mesenchymal transition (EMT), which enhances invasiveness and metastasis. Although we previously reported that EMT could be induced by increasing CK2 activity alone, it is not known whether CK2 also plays an essential role in TGFβ-induced EMT. Therefore, in the present study, we investigated whether TGFβ signaling could activate CK2 and, if so, whether such activation is required for TGFβ-induced EMT. We found that CK2 is activated by TGFβ treatment, and that activity peaks at 48 h after treatment. CK2 activation is dependent on TGFβ receptor (TGFBR) I kinase activity, but independent of SMAD4. Inhibition of CK2 activation through the use of either a CK2 inhibitor or shRNA against CSNK2A1 inhibited TGFβ-induced EMT. TGFβ signaling decreased CK2β but did not affect CK2α protein levels, resulting in a quantitative imbalance between the catalytic α and regulatory β subunits, thereby increasing CK2 activity. The decrease in CK2β expression was dependent on TGFBRI kinase activity and the ubiquitin-proteasome pathway. The E3 ubiquitin ligases responsible for TGFβ-induced CK2β degradation were found to be CHIP and WWP1. Okadaic acid (OA) pretreatment protected CK2β from TGFβ-induced degradation, suggesting that dephosphorylation of CK2β by an OA-sensitive phosphatase might be required for CK2 activation in TGFβ-induced EMT. Collectively, our results suggest CK2 as a therapeutic target for the prevention of EMT and metastasis of cancers.

SUBMITTER: Kim S

PROVIDER: S-EPMC6165993 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:Hepatocellular carcinoma (HCC) frequently unfolds under an inflammatory condition, which is a hub for a plethora of cytokines. A better understanding of the cytokine functions and their contributions to disease development is key to design of future therapeutic strategies and reduction of global HCC burden. In this context, one of the major cytokines present in the HCC tumour milieu is the transforming growth factor-β (TGF-β). One of its classical functions involve facilitation of epithelial to mesenchymal transition (EMT), in tumour cells, promoting an invasive phenotype. In spite of its clinical relevance, the cellular events associated with TGF-β-induced EMT and its molecular regulation is poorly elucidated. Therefore, as part of this study, we treated HCC cells with TGF-β and characterized the cellular processes associated with EMT. Interestingly, EMT triggered by TGF-β was found to be associated with cytostasis and altered cellular metabolism. TGF-β resulted in down-regulation of cell cycle-associated transcripts, like Cyclin A2 (CCNA2), and metabolic genes, like Glutamic-oxaloacetic transaminase 1 (GOT1) through epigenetic silencing. An overall increase in total histone repressive mark (H3K27me3) associated with a specific enrichment of H3K27me3 at the upstream promoter region of CCNA2 and GOT1 was observed after TGF-β exposure, leading to their down-regulation. Importantly, TGF-β-downstream signalling mediator- SMAD and chromatin repressive complex member-enhancer of zeste homolog 2 (EZH2) were found to co-immunoprecipitate and were required for the above effects. Overall, our findings reflect that HCC cells undergoing EMT, attain cytostasis and modulate metabolic demands to efficiently facilitate the EMT differentiation switch, and these events are regulated at the epigenomic level through TGF-β-mediated signalling. Our results provide better understanding of cellular invasive features which can lead to development of novel therapeutic strategies.

Project description:PurposeTransforming growth factor-β (TGF-β) is considered to be essential to induce epithelial-to-mesenchymal transition (EMT) which plays central roles in wound healing in ocular fibrotic complication. The present study investigates whether small interference RNAs (siRNAs) targeting the type II receptor of TGF-β (TβRII) could be used to minimize the TGF-β action.MethodsTGF-β receptor type II (TβRII) specific siRNAs designed from the Nakamura human gene sequence were used to transfect the cultured lens epithelial cells (LECs). The optimal transfection of scramble siRNA-Cy3 labeled duplexes in cultured LECs were examined by laser scanning confocal microscope and flow cytometry. TβRII protein expression and transcript levels were analyzed by immunofluorescence, western blotting, and real time PCR, respectively. Western blotting was performed to examine protein expression of fibronectin and alpha-smooth muscle actin (α-SMA). Scratch assay was used to determine cell migration. Cell morphology was observed after transfection by inverted microscope.ResultsThe optimal transfection rate of scramble siRNA-Cy3 labeled duplexes was efficient in that nearly to 50% in cultured LECs. TβRII specific siRNAs significantly reduced the receptor transcript and protein expression in cultured LECs. The gene knockdown inhibited LECs transdifferentiation, as it abrogated the expression of fibronectin and α-SMA, and retarded cell migration on the scratch assay. In addition, after transfection with TβRII specific siRNA, the cultured LECs did not show fibroblast-like shape which was one of the feature signs of EMT. Wound scratch assays indicated that the number of cultured LECs migrated into the wounded area was significantly lower in TβRII specific siRNA treated group (12.8 ± 3.27/7.85 mm(2)), compared with normal (57.8 ± 3.06/7.85 mm(2)) and scrambled RNA transfected group (50.8 ± 3.64/7.85 mm(2); p<0.0001).ConclusionsOur results provided additional evidence to support that TGF-β pathway was involved in the development of EMT of human posterior capsule opacification, while how TβRII was involved should be further investigated.

Dataset Information

Protein kinase CK2 activation is required for transforming growth factor β-induced epithelial-mesenchymal transition.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets