casein-kinase-ii and Carcinoma--Non-Small-Cell-Lung

Cisplatin is a platinum agent used in the treatment of non-small cell lung cancer (NSCLC). Much remains unknown regarding the basic operative mechanisms underlying cisplatin resistance in NSCLC. In this study, we found that phosphorylation of IGFBP-3 by CK2 (P-IGFBP-3) decreased its binding to hyaluronan (HA) but not to IGF-1 and rendered the protein less effective at reducing cell viability or increasing apoptosis than the non-phosphorylated protein with or without cisplatin in the human NSCLC cell lines, A549 and H1299. Our data suggest that blocking CD44 signaling augmented the effects of cisplatin and that IGFBP-3 was more effective at inhibiting HA-CD44 signaling than P-IGFBP-3. Blocking CK2 activity and HA-CD44 signaling increased cisplatin sensitivity and more effectively blocked the PI3K and AKT activities and the phospho/total NFκB ratio and led to increased p53 activation in A549 cells. Increased cell sensitivity to cisplatin was observed upon co-treatment with inhibitors targeted against PI3K, AKT, and NFκB while blocking p53 activity decreased A549 cell sensitivity to cisplatin. Our findings shed light on a novel mechanism employed by CK2 in phosphorylating IGFBP-3 and increasing cisplatin resistance in NSCLC. Blocking phosphorylation of IGFBP-3 by CK2 may be an effective strategy to increase NSCLC sensitivity to cisplatin.

Topics: Carcinoma, Non-Small-Cell Lung; Casein Kinase II; Cell Survival; Cisplatin; Humans; Hyaluronan Receptors; Hyaluronic Acid; Insulin-Like Growth Factor Binding Protein 3; Lung Neoplasms; Phosphatidylinositol 3-Kinases; Phosphorylation; Proto-Oncogene Proteins c-akt; Tumor Suppressor Protein p53

Immune cells can protect against tumor progression by killing cancer cells, while aberrant expression of the immune checkpoint protein PD-L1 (programmed death ligand 1) in cancer cells facilitates tumor immune escape and inhibits anti-tumor immunotherapy. As a serine/threonine kinase, CK2 (casein kinase 2) regulates tumor progression by multiple pathways, while it is still unclear the effect of CK2 on tumor immune escape. Here it is found that ING4 induced PD-L1 autophagic degradation and inhibites non-small cell lung cancer (NSCLC) immune escape by increasing T cell activity. However, clinical analysis suggests that high expression of CK2 correlates with low ING4 protein level in NSCLC. Further analysis shows that CK2 induce ING4-S150 phosphorylation leading to ING4 ubiquitination and degradation by JFK ubiquitin ligase. In contrast, CK2 gene knockout increases ING4 protein stability and T cell activity, subsequently, inhibites NSCLC immune escape. Furthermore, the combined CK2 inhibitor with PD-1 antibody effectively enhances antitumor immunotherapy. These findings provide a novel strategy for cancer immunotherapy.

Topics: B7-H1 Antigen; Carcinoma, Non-Small-Cell Lung; Casein Kinase II; Cell Cycle Proteins; Homeodomain Proteins; Humans; Immunotherapy; Lung Neoplasms; Tumor Suppressor Proteins

Casein-kinase CK2 is a Ser/Thr protein kinase that fosters cell survival and proliferation of malignant cells. The CK2 holoenzyme, formed by the association of two catalytic alpha/alpha' (CK2α/CK2α') and two regulatory beta subunits (CK2β), phosphorylates diverse intracellular proteins partaking in key cellular processes. A handful of such CK2 substrates have been identified as targets for the substrate-binding anticancer peptide CIGB-300. However, since CK2β also contains a CK2 phosphorylation consensus motif, this peptide may also directly impinge on CK2 enzymatic activity, thus globally modifying the CK2-dependent phosphoproteome. To address such a possibility, firstly, we evaluated the potential interaction of CIGB-300 with CK2 subunits, both in cell-free assays and cellular lysates, as well as its effect on CK2 enzymatic activity. Then, we performed a phosphoproteomic survey focusing on early inhibitory events triggered by CIGB-300 and identified those CK2 substrates significantly inhibited along with disturbed cellular processes. Altogether, we provided here the first evidence for a direct impairment of CK2 enzymatic activity by CIGB-300. Of note, both CK2-mediated inhibitory mechanisms of this anticancer peptide (i.e., substrate- and enzyme-binding mechanism) may run in parallel in tumor cells and help to explain the different anti-neoplastic effects exerted by CIGB-300 in preclinical cancer models.

Topics: Antineoplastic Agents; Carcinoma, Non-Small-Cell Lung; Casein Kinase II; Catalytic Domain; Cell Line, Tumor; Cell-Free System; Gene Expression Regulation, Neoplastic; Humans; Lung Neoplasms; Microscopy, Fluorescence; Peptides, Cyclic; Phosphorylation; Protein Binding; Proteome; Recombinant Proteins

The EGFR tyrosine kinase inhibitor gefitinib is commonly used for lung cancer patients. However, some patients eventually become resistant to gefitinib and develop progressive disease. Here, we indicate that ecto-ATP synthase, which ectopically translocated from mitochondrial inner membrane to plasma membrane, is considered as a potential therapeutic target for drug-resistant cells. Quantitative multi-omics profiling reveals that ecto-ATP synthase inhibitor mediates CK2-dependent phosphorylation of DNA topoisomerase IIα (topo IIα) at serine 1106 and subsequently increases the expression of long noncoding RNA, GAS5. Additionally, we also determine that downstream of GAS5, p53 pathway, is activated by ecto-ATP synthase inhibitor for regulation of programed cell death. Interestingly, GAS5-proteins interactomic profiling elucidates that GAS5 associates with topo IIα and subsequently enhancing the phosphorylation level of topo IIα. Taken together, our findings suggest that ecto-ATP synthase blockade is an effective therapeutic strategy via regulation of CK2/phospho-topo IIα/GAS5 network in gefitinib-resistant lung cancer cells.

Topics: Antineoplastic Agents; Apoptosis; ATP Synthetase Complexes; Carcinoma, Non-Small-Cell Lung; Casein Kinase II; Cell Line, Tumor; Cell Membrane; Cell Proliferation; Cell Survival; DNA Topoisomerases, Type II; Drug Resistance, Neoplasm; Gefitinib; Gene Ontology; Humans; Immunohistochemistry; Lung Neoplasms; Oligonucleotide Array Sequence Analysis; Phosphorylation; Protein Kinase Inhibitors; Proteomics; RNA, Long Noncoding; RNA, Small Interfering; Signal Transduction; Tandem Mass Spectrometry; Tumor Suppressor Protein p53

Tumor microenvironment (TME) plays a vital role in determining the outcomes of radiotherapy. As an important component of TME, vascular endothelial cells are involved in the perivascular resistance niche (PVRN), which is formed by inflammation or cytokine production induced by ionizing radiation (IR). Protein kinase CK2 is a constitutively active serine/threonine kinase which plays a vital role in cell proliferation and inflammation. In this study, we investigated the potential role of CK2 in PVRN after IR exposure.. Specific CK2 inhibitors, Quinalizarin and CX-4945, were employed to effectively suppressed the kinase activity of CK2 in human umbilical vein endothelial cells (HUVECs) without affecting their viability. Results showing that conditioned medium from IR-exposed HUVECs increased cell viability of A549 and H460 cells, and the pretreatment of CK2 inhibitors slowed down such increment. The secretion of IL-8 and IL-6 in HUVECs was induced after exposure with IR, but significantly inhibited by the addition of CK2 inhibitors. Furthermore, IR exposure elevated the nuclear phosphorylated factor-κB (NF-κB) p65 expression in HUVECs, which was a master factor regulating cytokine production. But when pretreated with CK2 inhibitors, such elevation was significantly suppressed.. This study indicated that protein kinase CK2 is involved in the key process of the IR induced perivascular resistant niche, namely cytokine production, by endothelial cells, which finally led to radioresistance of non-small cell lung cancer cells. Thus, the inhibition of CK2 may be a promising way to improve the outcomes of radiation in non-small cell lung cancer cells.

Topics: Anthraquinones; Blotting, Western; Carcinoma, Non-Small-Cell Lung; Casein Kinase II; Cytokines; Endothelial Cells; Endothelium, Vascular; Humans; Lung Neoplasms; Naphthyridines; Phenazines; Protein Kinase Inhibitors

Protein kinase CK2 is a ubiquitously expressed kinase in eukaryotes, which is known to phosphorylate many protein substrates. Because CK2 is involved in the regulation of various signaling pathways, we wondered whether CK2 participated in the regulation of ionizing radiation (IR) induced biological process. In this study, we investigated the effect of IR on the subcellular localization and kinase activity in human non-small cell lung cancer (NSCLC) cells. Immunofluorescent results showed that CK2 subunits shuttle into the nucleus mostly beginning 1 h after IR and lasting more than 6 h. We also conducted in vitro kinase assay and observed an increase in CK2 kinase activity at 6 h after IR. Furthermore, an increase in S phase was observed at 6 h after IR. Colony formation assay results demonstrated that CK2 inhibitor CX-4945 significantly enhanced the effect of irradiation in NSCLC cells. These results indicated that CK2 may be implicated in the regulation of IR-induced biological process.

Topics: Carcinoma, Non-Small-Cell Lung; Casein Kinase II; Cell Cycle; Cell Line, Tumor; Cell Nucleus; Cell Survival; Cytoplasm; Cytosol; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Neoplastic; Genotype; Humans; Lung Neoplasms; Naphthyridines; Phenazines; Phosphorylation; Radiation, Ionizing; Signal Transduction

Non-small cell lung carcinoma (NSCLC), a malignancy of lungs, is very aggressive and usually ends up with a dismal prognosis. Cisplatin (CDDP)-based systemic chemotherapy is the main pharmaceutical approach for treating NSCLC, but its effect is discounted by some hitherto unknown reasons. Thus, this study is dedicated to improving the efficacy of CDDP. Our results show that combining use of CDDP with CK2 siRNA or inhibitor is more efficient in suppressing cancer cell growth and promoting apoptosis than use of CDDP alone. The underlying mechanism is that CDDP has two pathways to go: one is that it directly induces apoptosis and the other is that it activates CK2, which suppresses proapoptosis gene promyelocytic leukemia (PML). In conclusion, inhibiting CK2 can enhance sensitivity of CDDP to NSCLC cancer cells through PML.

Topics: A549 Cells; Carcinoma, Non-Small-Cell Lung; Casein Kinase II; Cisplatin; Humans; Lung Neoplasms; Promyelocytic Leukemia Protein; Protein Kinase Inhibitors; Up-Regulation

Protein kinase CK2 is a highly conserved protein Ser/Thr protein kinase and plays important roles in cell proliferation, protein translation and cell survival. This study investigated the possibility of using CK2 inhibition as a new approach for increasing the efficacy of radiotherapy in non-small cell lung cancer (NSCLC) and its underlying mechanisms. Kinase inhibition of CK2 was attempted either by using the specific CK2 inhibitor, Quinalizarin or by applying siRNA interference technology to silence the expression of the catalytic subunit of CK2 in A549 and H460 cells. The results showed that CK2α knockdown or Quinalizarin significantly enhanced the radiosensitivity of various NSCLC cells. The notable findings we observed after exposure to both CK2 inhibition and ionizing radiation (IR) were a prolonged delay in radiation-induced DNA double-strand breaks (DSB) repair, robust G2/M checkpoint arrest and increased apoptosis. In vivo studies further demonstrated that compared with each treatment alone, CK2 inhibition combined with IR reduced tumor growth in the H460 cell xenograft model. In conclusion, CK2 is a promising target for the enhancement of radiosensitivity in NSCLC.

Topics: A549 Cells; Animals; Apoptosis; Blotting, Western; Carcinoma, Non-Small-Cell Lung; Casein Kinase II; Cell Cycle; Cell Line, Tumor; DNA Breaks, Double-Stranded; Female; Flow Cytometry; Humans; Immunohistochemistry; Lung Neoplasms; Mice; Mice, Inbred BALB C; Mice, Nude; Reverse Transcriptase Polymerase Chain Reaction; Xenograft Model Antitumor Assays

Breast cancer metastasis suppressor 1 (BRMS1) is decreased in non-small cell lung cancer (NSCLC) and other solid tumors, and its loss correlates with increased metastases. We show that BRMS1 is posttranslationally regulated by TNF-induced casein kinase 2 catalytic subunit (CK2α') phosphorylation of nuclear BRMS1 on serine 30 (S30), resulting in 14-3-3ε-mediated nuclear exportation, increased BRMS1 cytosolic expression, and ubiquitin-proteasome-induced BRMS1 degradation. Using our in vivo orthotopic mouse model of lung cancer metastases, we found that mutation of S30 in BRMS1 or the use of the CK2-specific small-molecule inhibitor CX4945 abrogates CK2α'-induced cell migration and invasion and decreases NSCLC metastasis by 60-fold. Analysis of 160 human NSCLC specimens confirmed that tumor CK2α' and cytoplasmic BRMS1 expression levels are associated with increased tumor recurrence, metastatic foci, and reduced disease-free survival. Collectively, we identify a therapeutically exploitable posttranslational mechanism by which CK2α-mediated degradation of BRMS1 promotes metastases in lung cancer. Cancer Res; 76(9); 2675-86. ©2016 AACR.

Topics: Active Transport, Cell Nucleus; Animals; Blotting, Western; Carcinoma, Non-Small-Cell Lung; Casein Kinase II; Disease Models, Animal; Disease-Free Survival; Fluorescent Antibody Technique; Heterografts; Immunohistochemistry; Immunoprecipitation; Kaplan-Meier Estimate; Lung Neoplasms; Mice; Neoplasm Invasiveness; Repressor Proteins; Tissue Array Analysis

The response to chemotherapeutic drugs in non-small cell lung cancer (NSCLC) is unsatisfactory, leading to poor outcomes. This study the aimed to investigates anticancer effects of CX-4945, a potent casein kinase II (CK2) inhibitor, in chemorefractory NSCLC cells.. Cell proliferation and apoptosis assay were carried-out by annexin V-FITC and FACScan after drug treatment with paclitaxel, cisplatin and CX-4945. AKT/mTOR and CK2α signals were measured by western blotting. Treatment was carried-out using siRNA to inhibit CK2α.. Paclitaxel, and cisplatin effectively inhibited cell proliferation and induced apoptosis in A549 cells, while not in H1299, Calu-1 and H358 cells. In these chemorefractory cell lines, AKT signalling was maintained despite drug treatment. However, CX-4945 suppressed cell growth, with cell-cycle arrest at G2/M phase and induced apoptosis with an increase of cleaved caspase-3 and PARP1 in a dose-dependent manner. Accordingly, AKT and its downstream signals such as mTOR and p70S6K were down-regulated by CX-4945. Transfection of CK2α siRNA had similar effects to CX-4945 treatment on cell proliferation and apoptosis.. CX-4945 shows a promising anticancer action through down-regulation of AKT/mTOR signals, suggesting its possible application for treatment of chemorefractory lung cancer.

Topics: Apoptosis; Carcinoma, Non-Small-Cell Lung; Casein Kinase II; Cell Cycle Checkpoints; Cell Line, Tumor; Cisplatin; Down-Regulation; Humans; Lung Neoplasms; Naphthyridines; Paclitaxel; Phenazines; Proto-Oncogene Proteins c-akt; TOR Serine-Threonine Kinases

Dysfunction of ribosomal proteins (RPs) may play an important role in molecular tumorigenesis, such as lung cancer, acting in extraribosomal functions. Many protein-protein interaction studies and genetic screens have confirmed the extraribosomal capacity of RPs. As reported, ribosomal protein L22 (RPL22) dysfunction could increase cancer risk. In the present study, we examined RPL22-protein complexes in lung cancer cells. Tandem affinity purification (TAP) was used to screen the RPL22-protein complexes, and GST pull-down experiments and confocal microscopy were used to assess the protein-protein interaction. The experiment of kinase assay was used to study the function of the RPL22-protein complexes. The results showed that several differentially expressed proteins were isolated and identified by LC-MS/MS, which revealed that one of the protein complexes included casein kinase 2α (CK2α). RPL22 and CK2α interact in vitro. RPL22 also inhibited CK2α substrate phosphorylation in vitro. This is the first report of the RPL22-CK2α relationship in lung cancer. Dysregulated CK2 may impact cell proliferation and apoptosis, key features of cancer cell biology. Our results indicate that RPL22 may be a candidate anticancer agent due to its CK2α-binding and -inhibitory functions in human lung cancer.

Topics: Apoptosis; Carcinoma, Non-Small-Cell Lung; Casein Kinase II; Cell Line, Tumor; Cell Proliferation; Gene Expression Regulation, Neoplastic; HEK293 Cells; Humans; Lung Neoplasms; Protein Binding; Ribosomal Proteins; RNA-Binding Proteins; Tandem Mass Spectrometry

Radioresistance is considered as a main factor restricting efficacy of radiotherapy. However, the exact molecular mechanism of radioresistance has not been explained yet. In this study, to elucidate radioresistance mechanism in lung cancer, we compared radiation responses in two types of non-small cell lung cancer (NSCLC) cells with different radiosensitivity and identified key molecules conferring radioresistance. In radioresistant NSCLC cells, ionizing radiation (IR) led to casein kinase 2α (CK2α)- and PKC-mediated phosphorylation of rpS3 and TRAF2, respectively, which induced dissociation of rpS3-TRAF2 complex and NF-κB activation, resulting in significant up-regulation of prosurvival genes (cIAP1, cIAP2, and survivin). Also, dissociated phospho-rpS3 translocated into nucleus and bound with NF-κB complex (p65 and p50), contributing to p65 DNA binding property and specificity. However, in radiosensitive NSCLC cells, IR-mediated rpS3 phosphorylation was not detected due to the absence of CK2α overexpression. Consequently, IR-induced rpS3-TRAF2 complex dissociation, NF-κB activation, and prosurvival gene expression were not presented. Taken together, our findings revealed a novel radioresistance mechanism through functional orchestration of rpS3, TRAF2, and NF-κB in NSCLC cells. Moreover, we provided the first evidence for the function of rpS3 as a new TRAF2-binding protein and demonstrated that phosphorylation of both rpS3 and TRAF2 is a key control point of radioresistance in NSCLC cells. These results suggest that regulation of rpS3 and TRAF2 in combination with radiotherapy could have high pharmacological therapeutic potency for radioresistance of NSCLC.

Topics: Apoptosis; Carcinoma, Non-Small-Cell Lung; Casein Kinase II; Cell Line, Tumor; Cell Nucleus; Humans; Lung Neoplasms; Models, Biological; NF-kappa B; Phosphorylation; Protein Binding; Protein Transport; Radiation Tolerance; Radiation, Ionizing; Ribosomal Proteins; TNF Receptor-Associated Factor 2

Cell surface nucleolin (NCL) plays fundamental roles in tumor angiogenesis. However, the mechanism underlying its surface translocation remains obscure. The present study discovered that heat shock cognate 70 (Hsc70) is essential in both the surface translocation and the angiogenic function of NCL.. We identified that Hsc70 interacted with NCL in endothelial cells via the peptide-binding domain of Hsc70 and the RNA-binding domain of NCL. Functional knockdown of Hsc70 remarkably inhibited the expression of surface NCL, which was rescued by wild-type Hsc70 rather than its truncations. Phosphorylation of NCL by either protein kinase C-ξ or casein kinase 2 mediated its interaction with Hsc70 and the surface expression. Hsc70 regulated NCL translocation via stabilizing NCL and enhancing its interaction with nonmuscle myosin heavy chain 9. Moreover, Hsc70 was associated with NCL-induced endothelial cell migration and tubule formation in vitro and angiogenesis in both matrigel plugs and xenograft tumors. Tissue array analysis revealed that the expression levels of NCL and Hsc70 were intimately correlated in human lung adenocarcinomas.. Our study demonstrates that Hsc70 is a prerequisite for the surface translocation and angiogenic function of NCL, which suggests strategies to target both Hsc70 and NCL for more effective antiangiogenic therapies.

Topics: Adenocarcinoma; Adenocarcinoma of Lung; Animals; Benzhydryl Compounds; Binding Sites; Carcinoma, Non-Small-Cell Lung; Casein Kinase II; Cell Line, Tumor; Cell Movement; HSC70 Heat-Shock Proteins; Human Umbilical Vein Endothelial Cells; Humans; Lung Neoplasms; Mice; Mice, Nude; Myosin Heavy Chains; Neovascularization, Pathologic; Neovascularization, Physiologic; Nucleolin; Phosphoproteins; Phosphorylation; Protein Interaction Domains and Motifs; Protein Interaction Mapping; Protein Kinase C-epsilon; Protein Stability; Protein Transport; Pyrrolidinones; RNA Interference; RNA-Binding Proteins; Tissue Array Analysis; Transfection; Xenograft Model Antitumor Assays

Protein kinase CK2 is frequently elevated in a variety of human cancers. The Hedgehog (Hh) signaling pathway has been implicated in stem cell maintenance, and its aberrant activation has been indicated in several types of cancer, including lung cancer. In this study, we show that CK2 is positively involved in Hh/Gli signaling in lung cancer cell lines A549 and H1299. First, we found a correlation between CK2α and Gli1 mRNA levels in 100 primary lung cancer tissues. Down-regulation of Gli1 expression and transcriptional activity were demonstrated after the silencing of CK2α in lung cancer cells. In addition, CK2α siRNA down-regulated the expression of Hh target genes. Furthermore, two small-molecule CK2α inhibitors led to a dose-dependent inhibition of Gli1 expression and transcriptional activity in lung cancer cells. Reversely, forced over-expression of CK2α resulted in an increase both in Gli1 expression and transcriptional activity in A549 cells. Finally, the inhibition of Hh/Gli by CK2α siRNA led to a reduction of a cancer stem cell-like side population that shows higher ABCG2 expression level. Thus, we report that the inhibition of CK2α down-regulates Hh/Gli signaling and subsequently reduces stem-like side population in human lung cancer cells.

Topics: ATP Binding Cassette Transporter, Subfamily G, Member 2; ATP-Binding Cassette Transporters; Carcinoma, Non-Small-Cell Lung; Casein Kinase II; Cell Count; Cell Line, Tumor; Down-Regulation; Gene Expression Regulation, Neoplastic; Gene Knockdown Techniques; Gene Silencing; Humans; Lung Neoplasms; Neoplasm Proteins; Neoplastic Stem Cells; Protein Kinase Inhibitors; Proteolysis; Side-Population Cells; Signal Transduction; Small Molecule Libraries; Transcription Factors; Transcription, Genetic; Transcriptional Activation; Up-Regulation; Zinc Finger Protein GLI1

The ephrin and Eph signaling circuit has been reported as deregulated in a number of tumor types including nonsmall cell lung cancer (NSCLC). Here we show that suppression of the ephrin-familly member ephrin B3 decreases NSCLC cell proliferation and has profound effects on cell morphology. To reveal which signaling networks ephrin B3 utilize to regulate such effects on growth and morphology, differential regulation of phosphorylated proteins was analyzed in the NSCLC cell line U-1810. Using strong cat ion exchange (SCX) and TiO(2)-based fractionation followed by nano-LC and mass spectrometry analysis, we identified 1083 unique phosphorylated proteins. Out of these, 150 proteins were found only when ephrin B3 is expressed, whereas 66 proteins were found exclusively in U-1810 cells with silenced ephrin B3. Network analysis of changes in the phosphoproteome with regard to the presence or absence of ephrin B3 expression generated a hypothesis that the site specific phosphorylation on Ser-897 detected on the erythropoietin-producing hepatocellular receptor tyrosine kinase class A2 (EphA2) is critical for the survival of NSCLC cells. Upstream of the EphA2 phosphorylation, activation of Akt1 on Ser 129 was also revealed as part of the ephrin B3-mediated signaling pathway. Phosphorylation of these sites was further confirmed by immune-based strategies in combination with mass spectrometry. Moreover, by further stepwise pathway walking, annotating the phosphorylated sites and their corresponding kinases upstream, our data support the process in which a Heat shock protein 90 isoform (HSP90AA1) acts as a protector of EphA2, thereby saving it from degradation. In addition, protein kinase CK2 (CK2) is suggested as a dominant kinase, activating downstream substrates to generate the effects on NSCLC proliferation and morphology.

Topics: Carcinoma, Non-Small-Cell Lung; Casein Kinase II; Cell Line, Tumor; Cell Proliferation; Cell Survival; Ephrin-B3; Humans; Phosphoproteins; Phosphorylation; Proteomics; Proto-Oncogene Proteins c-akt; Receptor, EphA2; Signal Transduction

CK2 interacts and phosphorylates >300 proteins, including Stat3, and is linked to a number of human cancers. Constitutively activated Stat3 has been reported in 50% of human lung cancers. Inhibition of CK2 activity can induce apoptosis and suppression of Stat3 activation in cancer cells. This study examined the effects of CK2 inhibitors on growth inhibition of lung cancer cells and the therapeutic potential on lung cancer. The CK2 inhibitor and radiation both suppressed cancer cell growth in a dose-dependent manner. Besides, the cytotoxic effect of irradiation could be augmented by CK2 inhibitors (p<0.05, two-way analysis of variance and Tukey's Honestly Significant Difference). Moreover, the growth inhibition of CK2 inhibitor and irradiation was both associated with suppression of Stat3 activation. Taken together, inhibition of CK2 activity appears to be a promising treatment strategy for non-small cell lung cancer and CK2 inhibition results in reduced Stat3 activation. Our data warrant further effort to develop CK2-targeted radiosensitizer for lung cancer treatment.

Topics: Carcinoma, Non-Small-Cell Lung; Casein Kinase II; Cell Line, Tumor; Cell Survival; Dose-Response Relationship, Drug; Dose-Response Relationship, Radiation; Enzyme Inhibitors; Epidermal Growth Factor; Gene Expression Regulation, Neoplastic; Humans; Lung Neoplasms; Radiation Tolerance; Radiation-Sensitizing Agents; STAT3 Transcription Factor

To analyze the prognostic significance of the genes casein kinase 2 alpha subunit (CSNK2A1), anti-apoptosis clone-11 (AAC-11), and tumor metastasis suppressor NME1 in completely resected non-small cell lung cancer (NSCLC) patients.. Total RNA was extracted from 145 cases of completely resected, formalin-fixed, paraffin-embedded NSCLC tissues. mRNA expression levels of CSNK2A1, AAC-11, and NME1 were detected by real-time reverse-transcriptase polymerase chain reaction. Univariate and multivariate survival analyses were used to identify factors related to prognosis.. A correlation between CSNK2A1 and AAC-11 mRNA expression levels (rs=0.366, p=0.000) was found. Univariate analysis showed that high expression of CSNK2A1 and AAC-11 was predictive of poor prognosis in NSCLC patients (p=0.029 and 0.044, respectively), especially when expression levels of both genes were concomitantly high (p=0.007). Multivariate Cox regression analysis showed that high expression of CSNK2A1, or concomitantly high expression of CSNK2A1 and AAC-11, are independent prognostic factors of poor survival in NSCLC patients. However, NME1 mRNA expression level did not significantly influence survival in NSCLC patients.. This retrospective study indicates that CSNK2A1 and AAC-11, especially in combination, are useful prognosis markers in NSCLC patients after complete resection, independent of lymph node metastasis status.

Topics: Adult; Aged; Apoptosis Regulatory Proteins; Carcinoma, Non-Small-Cell Lung; Casein Kinase II; Female; Gene Expression Regulation, Neoplastic; Humans; Kaplan-Meier Estimate; Lung Neoplasms; Male; Middle Aged; NM23 Nucleoside Diphosphate Kinases; Nuclear Proteins; Prognosis; RNA, Messenger

The PML tumor suppressor controls growth suppression, induction of apoptosis, and cellular senescence. PML loss occurs frequently in hematopoietic and solid tumors. PML loss often correlates with tumor progression. Casein kinase 2 (CK2) is a stress-activated serine/threonine protein kinase that is oncogenic and frequently overexpressed in human tumor of multiple histological origins. In addition, CK2 overexpression due to gene amplification has been reported to be an adverse prognostic factor in non-small cell lung cancer. At the 5th International Conference on Protein Kinase CK2 in Padova, Italy, we reviewed our recent findings that PML undergoes ubiquitin/proteasome-mediated degradation in immortalized and tumor derived cell lines. PML degradation depends on direct CK2 phosphorylation of PML Ser517. PML mutants that are resistant to CK2 phosphorylation display increased tumor suppressive functions in assays measuring apoptosis, replicative senescence, and in xenograft models. More significantly, CK2 pharmacological inhibition enhances PML tumor suppressive property. These data identify a key post-translational mechanism that controls PML protein levels in cancer cells and suggest that CK2 inhibitors may be beneficial anti-cancer drugs.

Topics: Amino Acid Sequence; Animals; Carcinoma, Non-Small-Cell Lung; Casein Kinase II; Cell Line, Tumor; Enzyme Activation; Humans; Lung Neoplasms; Mice; Mice, Nude; Molecular Sequence Data; Mutation; Nuclear Proteins; p38 Mitogen-Activated Protein Kinases; Phosphorylation; Promyelocytic Leukemia Protein; Proteasome Endopeptidase Complex; Protein Kinase Inhibitors; Protein Processing, Post-Translational; Thermodynamics; Transcription Factors; Tumor Suppressor Proteins; Ubiquitin; Ubiquitination

The antitumor efficacy of the CK2 inhibitors so far described has not been extensively evaluated in cancer animal models. We have previously demonstrated that a proapoptotic cyclic peptide termed P15 delivered into the cells by the Tat Cell Penetrating Peptide was able to abrogate the CK2-mediated phosphorylation and induce tumor regression when injected directly into solid tumors in mice. Here we explored the antitumor effect by systemic administration of P15-Tat in a consecutive 5-day schedule through either intraperitoneal or intravenous route. Importantly, significant delay of tumor growth was observed at 2 mg/kg (p < 0.05), 10 mg/kg (p < 0.01) or 40 mg/kg (p < 0.001) after P15-Tat administration both in syngeneic murine tumors and human tumors xenografted in nude mice. In line with this, the systemic administration of P15-Tat induced apoptosis in the tumor as evidenced by in situ DNA fragmentation. Furthermore, we evidenced that 99mTc-labeled P15-Tat peptide was certainly accumulated on the tumors after administration by both routes. This report becomes the first describing the antitumor effect induced by systemic administration of a peptide that targets the acidic phosphorylation domain for CK2 substrates. Also, our data reinforces the perspectives of P15-Tat for the cancer targeted therapy.

Topics: Animals; Apoptosis; Carcinoma, Non-Small-Cell Lung; Casein Kinase II; Cell Line, Tumor; Cyclin-Dependent Kinase Inhibitor p15; Female; Gene Products, tat; Humans; Lung Neoplasms; Mice; Mice, Inbred C57BL; Mice, Nude; Peptides, Cyclic; Phosphorylation; Protein Kinase Inhibitors; Tissue Distribution; Transplantation, Heterologous

The PML protein induces senescence, and, upon oncogenic stress, its absence promotes cellular transformation. In this issue of Cell, Scaglioni et al. (2006) show that phosphorylation of PML by CK2, a kinase frequently activated in human cancers, promotes PML degradation. Therefore, pharmacological inhibition of CK2-induced PML loss could be used to offset tumor establishment.

Topics: Carcinoma, Non-Small-Cell Lung; Casein Kinase II; Cell Transformation, Neoplastic; Enzyme Activation; Gene Expression Regulation, Neoplastic; Genes, Tumor Suppressor; Humans; Lung Neoplasms; Neoplasm Proteins; Nuclear Proteins; Phosphorylation; Promyelocytic Leukemia Protein; Proteasome Endopeptidase Complex; Transcription Factors; Tumor Suppressor Proteins

The PML tumor suppressor controls key pathways for growth suppression, induction of apoptosis, and cellular senescence. PML loss occurs frequently in human tumors through unknown posttranslational mechanisms. Casein kinase 2 (CK2) is oncogenic and frequently upregulated in human tumors. Here we show that CK2 regulates PML protein levels by promoting its ubiquitin-mediated degradation dependent on direct phosphorylation at Ser517. Consequently, PML mutants that are resistant to CK2 phosphorylation display increased tumor-suppressive functions. In a faithful mouse model of lung cancer, we demonstrate that Pml inactivation leads to increased tumorigenesis. Furthermore, CK2 pharmacological inhibition enhances the PML tumor-suppressive property in vivo. Importantly, we found an inverse correlation between CK2 kinase activity and PML protein levels in human lung cancer-derived cell lines and primary specimens. These data identify a key posttranslational mechanism that controls PML protein levels and provide therapeutic means toward PML restoration through CK2 inhibition.

Topics: Amino Acid Sequence; Amino Acid Substitution; Animals; Apoptosis; Carcinoma, Non-Small-Cell Lung; Casein Kinase II; Cell Line; Cell Line, Transformed; Cell Line, Tumor; Enzyme Activation; Enzyme Inhibitors; Genes, Tumor Suppressor; Green Fluorescent Proteins; Hemagglutinins; Humans; Leupeptins; Lung Neoplasms; Mice; Mice, Transgenic; Molecular Sequence Data; Neoplasm Proteins; NIH 3T3 Cells; Nuclear Proteins; p38 Mitogen-Activated Protein Kinases; Phosphorylation; Promyelocytic Leukemia Protein; Proteasome Endopeptidase Complex; Protein Structure, Tertiary; Protein Subunits; RNA, Small Interfering; Sequence Deletion; Serine; Sorbitol; Transcription Factors; Transcriptional Activation; Triazoles; Tumor Suppressor Proteins; Ubiquitin