casein-kinase-ii and Esophageal-Neoplasms

Aberrant expression of casein kinase 2 (CK2) is associated with tumor progression; however, the molecular mechanism by which CK2 modulates tumorigenesis is incompletely understood. In this paper, we show that CK2α phosphorylates the C-terminal domain of the nuclear receptor corepressor (NCoR) at Ser-2436 to stabilize the NCoR against the ubiquitin-dependent proteasomal degradation pathway. Importantly, NCoR promoted the invasion of esophageal cancer cells in a CK2-dependent manner. By using cyclic DNA microarray analysis, we identified CXCL10/IP-10 as a novel CK2α-NCoR cascade-regulated gene. The depletion of both NCoR and HDAC3 commonly derepressed IP-10 transcription, demonstrating the functional engagement of the NCoR-HDAC3 axis in IP-10 transcriptional repression. Furthermore, chromatin immunoprecipitation assays showed that c-Jun recruits NCoR-HDAC3 corepressor complexes to the (AP1 site of IP-10, leading to histone hypoacetylation and IP-10 down-regulation. Collectively these data suggest that the CK2α-NCoR cascade selectively represses the transcription of IP-10 and promotes oncogenic signaling in human esophageal cancer cells.

Topics: Binding Sites; Casein Kinase II; Cell Line, Tumor; Cell Transformation, Neoplastic; Chemokine CXCL10; Co-Repressor Proteins; Esophageal Neoplasms; Gene Expression Regulation, Neoplastic; Histone Deacetylases; Humans; JNK Mitogen-Activated Protein Kinases; Neoplasm Invasiveness; Nuclear Receptor Co-Repressor 1; Promoter Regions, Genetic; Protein Binding; Proteolysis; Signal Transduction; Transcription, Genetic

Previously, we reported that high PKCK2 activity could protect cancer cells from death receptor-mediated apoptosis through phosphorylation of procaspase-2. Because anoikis is another form of apoptosis, we asked whether PKCK2 could similarly confer resistance to anoikis on cancer cells. Human esophageal squamous cancer cell lines with high PKCK2 activity (HCE4 and HCE7) were anoikis-resistant, whereas cell lines with low PKCK2 activity (TE2 and TE3) were anoikis-sensitive. Because the cells showed different sensitivity to anoikis, we compared the expression of cell adhesion molecules between anoikis-sensitive TE2 and anoikis-resistant HCE4 cells using cDNA microarray. We found that E-cadherin is expressed only in TE2 cells; whereas N-cadherin is expressed instead of E-cadherin in HCE4 cells. To examine whether PKCK2 activity could determine the type of cadherin expressed, we first increased intracellular PKCK2 activity in TE2 cells by overexpressing the PKCK2α catalytic subunit using lentivirus and found that high PKCK2 activity could switch cadherin expression from type E to N and confer anoikis resistance. Conversely, a decrease in PKCK2 activity in HCE4 cells by knockdown of PKCK2α catalytic subunit using shRNA induced N- to E-cadherin switching and the anoikis-resistant cells became sensitive. In addition, N-cadherin expression correlated with PKB/Akt activation and increased invasiveness. We conclude that high intracellular PKCK2 activity confers anoikis resistance on esophageal cancer cells by inducing E- to N-cadherin switching.

Topics: Anoikis; Antigens, CD; Cadherins; Carcinoma; Casein Kinase II; Cell Line, Tumor; Cell Proliferation; Drug Resistance, Neoplasm; Esophageal Neoplasms; Extracellular Matrix; Gene Expression Regulation, Neoplastic; Gene Knockdown Techniques; Humans; Neoplasm Invasiveness; Phosphorylation; Signal Transduction

To investigate the expression of casein kinase 2β in esophageal carcinoma tissues and analyze its clinical significance.. The expression of CK2β in a tissue chip containing 60 normal esophageal mucosa and 60 colorectal cancer specimens were detected immunohistochemically. Ten human esophageal carcinoma and adjacent normal tissues were examined for the expression of CK2β protein and mRNA using Western blotting and real-time quantitative PCR, respectively.. A strong expression of CK2β was found in 85.71% of the esophageal cancer tissues; 1.79% of the cancer tissues were negative for CK2β expression, and 1.79% and 10.71% of the cancer tissues were weakly and moderately positive, respectively. In the normal mucosal tissues, 96.67% of the tissues were negative for CK2β and 3.33% showed weak CK2β expression, showing a significant difference in the distribution of CK2β between normal and esophageal carcinoma tissues (P<0.001). The expression level of CK2β in esophageal cancers was associated with the pathological stage (TNM) (P=0.010). Western blotting and real-time quantitative PCR also confirmed an increased CK2β expression in the esophageal cancer tissues.. The high expression of protein kinase CK2β is closely related to the carcinogenesis and malignancy of esophageal cancer.

Topics: Adult; Aged; Carcinoma, Squamous Cell; Casein Kinase II; Esophageal Neoplasms; Female; Gene Expression Regulation, Neoplastic; Humans; Male; Middle Aged; Neoplasm Staging

Insulin-like growth factor 1 (IGF-1) inhibits 5-fluorouracil (5-Fu)-induced apoptosis in esophageal carcinoma cells; however, the mechanisms for IGF-1-induced 5-Fu chemoresistance remain unknown. In the human esophageal carcinoma cell line, CE48T/VGH, we show that IGF-1 up-regulated survivin expression at the post-transcriptional level and this up-regulation is mediated by both the PI3-K/Akt and casein kinase 2 signaling pathways. We then examine whether IGF-1-induced 5-Fu chemoresistance is mediated through up-regulation of survivin. Ectopic expression of survivin inhibits 5-Fu-induced apoptosis; furthermore, the abolition of survivin expression sensitizes cells to 5-Fu treatment and prevents the anti-apoptotic function of IGF-1 in esophageal carcinoma cell lines. We also found that ectopic expression of survivin or treatment with IGF-1 inhibits the release of Smac/DIABLO and caspases activation after 5-Fu treatment. Our results strongly suggest that IGF-1 inhibits 5-Fu induced apoptosis through increasing survivin levels, which prevents Smac/DIABLO release and blocks the activation of caspases. Therefore, up-regulation of IGF-1 and survivin would seem to be responsible for 5-Fu chemoresistance in esophageal cancer patients and these factors may be the valuable predictors of 5-Fu chemoresistance in esophageal carcinoma.

Topics: Antimetabolites, Antineoplastic; Apoptosis; Apoptosis Regulatory Proteins; Blotting, Western; Casein Kinase II; Cell Line, Tumor; Drug Resistance, Neoplasm; Esophageal Neoplasms; Fluorouracil; Humans; Inhibitor of Apoptosis Proteins; Insulin-Like Growth Factor I; Intracellular Signaling Peptides and Proteins; Mitochondria; Mitochondrial Proteins; Oncogene Protein v-akt; Phosphatidylinositol 3-Kinases; Polymerase Chain Reaction; Signal Transduction; Survivin