CK2 modulation of NF-kappaB, TP53, and the malignant phenotype in head and neck cancer by anti-CK2 oligonucleotides in vitro or in vivo via sub-50-nm nanocapsules

CK2B is a Prognostic Biomarker and a Potential Drug Target for Hepatocellular Carcinoma

BACKGROUND

Although casein kinase II subunit beta (CK2B) was previously reported to be involved in human cancers, such as hepatocellular carcinoma (HCC), there has been no systematic assessment of CK2B in HCC.

OBJECTIVE

To assess the potential function of CK2B as a prognostic biomarker and possible druggable target in HCC.

METHODS

The Cancer Genome Atlas database was accessed to investigate the potential oncogenic and prognostic roles of CK2B in HCC. Diverse analytical methods were used to obtain a fuller understanding of CK2B, including CIBERSORT, The Tumor Immune Estimation Resource (TIMER), gene set enrichment analyses (GSEA), Kyoto Encyclopedia of Genes and Genomes (KEGG), and gene ontology (GO). Furthermore, the Comparative Toxicogenomic Database (CTD) was used to identify potential drugs to treat CK2B-overexpressing HCC. Patents for these drugs were reviewed using Patentscope® and Worldwide Espacenet®.

RESULTS

Upregulated CK2B expression was markedly associated with more aggressive pathological features, including G3, G4 (vs. G1, G2), and T2, T3 (vs. T1). Kaplan-Meier survival curves indicated that patients with HCC with higher expression of CK2B had worse overall survival (P = 0.005), progression-free interval (P = 0.001), and disease-specific survival (P = 0.011). GO and KEGG analysis revealed that CK2B dysregulation affects mitotic chromosome condensation, protein stabilization and binding, regulation of signal transduction of p53 class mediator, and cancer-related pathways. GSEA identified six well-known pathways, including MAPK, WNT, Hedgehog, and TGFβ signaling pathways. Finally, CTD identified six compounds that might represent targeted drugs to treat HCC with CK2B overexpression. A review of patents indicated these compounds showed promising anticancer results; however, whether CK2B interacts with these drugs and improves drug outcomes for patients with HCC was not confirmed.

CONCLUSION

CK2B is a biomarker for HCC prognosis and could be a potential new drug target. Moreover, the association between infiltrating immune cells and CK2B in the HCC tumor microenvironment might provide a solid basis for further investigation and a potent strategy for immunotherapy of HCC.

Casein Kinase 2 Affects Epilepsy by Regulating Ion Channels: A Potential Mechanism

Epilepsy, characterized by recurrent seizures and abnormal brain discharges, is the third most common chronic disorder of the Central Nervous System (CNS). Although significant progress has been made in the research on antiepileptic drugs (AEDs), approximately one-third of patients with epilepsy are refractory to these drugs. Thus, research on the pathogenesis of epilepsy is ongoing to find more effective treatments. Many pathological mechanisms are involved in epilepsy, including neuronal apoptosis, mossy fiber sprouting, neuroinflammation, and dysfunction of neuronal ion channels, leading to abnormal neuronal excitatory networks in the brain. CK2 (Casein kinase 2), which plays a critical role in modulating neuronal excitability and synaptic transmission, has been shown to be associated with epilepsy. However, there is limited research on the mechanisms involved. Recent studies have suggested that CK2 is involved in regulating the function of neuronal ion channels by directly phosphorylating them or their binding partners. Therefore, in this review, we will summarize recent research advances regarding the potential role of CK2 regulating ion channels in epilepsy, aiming to provide more evidence for future studies.

CSNK2A2 promotes hepatocellular carcinoma progression through activation of NF-κB pathway

INTRODUCTION AND OBJECTIVES

Breast and non-small cell lung cancers harbor an upregulated CSNK2A2 oncogene that encodes the protein kinase CK2 alpha', a catalytic subunit of the highly conserved serine/threonine kinase CK2. However, its role and biological significance in hepatocellular carcinoma (HCC) remains unclear.

MATERIALS AND METHODS

Western-blotting and immunohistochemistry were used to measure the expression of CSNK2A2 in HCC tumor tissues and cell lines. CCK8, Hoechst staining, transwell, tube formation assay in vitro and nude mice experiments in vivo were used to measure the effects of CSNK2A2 on HCC proliferation, apoptosis, metastasis, angiogenesis and tumor formation.

RESULTS

In the study, we showed that CSNK2A2 was highly expressed in HCC comparison with matched control tissues, and was linked with lower survival of patients. Additional experiments indicated that silencing of CSNK2A2 promoted HCC cell apoptosis, while inhibited HCC cells migrating, proliferating, angiogenesis both in vitro and in vivo. These effects were also accompanied by reduced expression of NF-κB target genes, including CCND1, MMP9 and VEGF. Moreover, treatment with PDTC counteracted the promotional effects of CSNK2A2 on HCC cells.

CONCLUSIONS

Overall, our results suggested that CSNK2A2 could promote HCC progression by activating the NF-κB pathway, and this could serve as a biomarker for future prognostic and therapeutic applications.

Protein Kinase CK2 Contributes to Glucose Homeostasis by Targeting Fructose-1,6-Bisphosphatase 1

Glucose homeostasis is of critical importance for the survival of organisms. It is under hormonal control and often coordinated by the action of kinases and phosphatases. We have previously shown that CK2 regulates insulin production and secretion in pancreatic β-cells. In order to shed more light on the CK2-regulated network of glucose homeostasis, in the present study, a qRT-PCR array was carried out with 84 diabetes-associated genes. After inhibition of CK2, fructose-1,6-bisphosphatase 1 (FBP1) showed a significant lower gene expression. Moreover, FBP1 activity was down-regulated. Being a central enzyme of gluconeogenesis, the secretion of glucose was decreased as well. Thus, FBP1 is a new factor in the CK2-regulated network implicated in carbohydrate metabolism control.

Protein kinase CK2 – diverse roles in cancer cell biology and therapeutic promise

The association of protein kinase CK2 (formerly casein kinase II or 2) with cell growth and proliferation in cells was apparent at early stages of its investigation. A cancer-specific role for CK2 remained unclear until it was determined that CK2 was also a potent suppressor of cell death (apoptosis); the latter characteristic differentiated its function in normal versus malignant cells because dysregulation of both cell growth and cell death is a universal feature of cancer cells. Over time, it became evident that CK2 exerts its influence on a diverse range of cell functions in normal as well as in transformed cells. As such, CK2 and its substrates are localized in various compartments of the cell. The dysregulation of CK2 is documented in a wide range of malignancies; notably, by increased CK2 protein and activity levels with relatively moderate change in its RNA abundance. High levels of CK2 are associated with poor prognosis in multiple cancer types, and CK2 is a target for active research and testing for cancer therapy. Aspects of CK2 cellular roles and targeting in cancer are discussed in the present review, with focus on nuclear and mitochondrial functions and prostate, breast and head and neck malignancies.

Inhibitory Response to CK II Inhibitor Silmitasertib and CDKs Inhibitor Dinaciclib Is Related to Genetic Differences in Pancreatic Ductal Adenocarcinoma Cell Lines

Casein kinase II (CK2) and cyclin-dependent kinases (CDKs) frequently interact within multiple pathways in pancreatic ductal adenocarcinoma (PDAC). Application of CK2- and CDK-inhibitors have been considered as a therapeutic option, but are currently not part of routine chemotherapy regimens. We investigated ten PDAC cell lines exposed to increasing concentrations of silmitasertib and dinaciclib. Cell proliferation, metabolic activity, biomass, and apoptosis/necrosis were evaluated, and bioinformatic clustering was used to classify cell lines into sensitive groups based on their response to inhibitors. Furthermore, whole exome sequencing (WES) and RNA sequencing (RNA-Seq) was conducted to assess recurrent mutations and the expression profile of inhibitor targets and genes frequently mutated in PDAC, respectively. Dinaciclib and silmitasertib demonstrated pronounced and limited cell line specific effects in cell death induction, respectively. WES revealed no genomic variants causing changes in the primary structure of the corresponding inhibitor target proteins. RNA-Seq demonstrated that the expression of all inhibitor target genes was higher in the PDAC cell lines compared to non-neoplastic pancreatic tissue. The observed differences in PDAC cell line sensitivity to silmitasertib or dinaciclib did not depend on target gene expression or the identified gene variants. For the PDAC hotspot genes kirsten rat sarcoma virus (KRAS) and tumor protein p53 (TP53), three and eight variants were identified, respectively. In conclusion, both inhibitors demonstrated in vitro efficacy on the PDAC cell lines. However, aberrations and expression of inhibitor target genes did not appear to affect the efficacy of the corresponding inhibitors. In addition, specific aberrations in TP53 and KRAS affected the efficacy of both inhibitors.

Targeting CK2 in cancer: a valuable strategy or a waste of time?

CK2 is a protein kinase involved in several human diseases (ranging from neurological and cardiovascular diseases to autoimmune disorders, diabetes, and infections, including COVID-19), but its best-known implications are in cancer, where it is considered a pharmacological target. Several CK2 inhibitors are available and clinical trials are underway in different cancer types. Recently, the suitability of CK2 as a broad anticancer target has been questioned by the finding that a newly developed compound, named SGC-CK2-1, which is more selective than any other known CK2 inhibitor, is poorly effective in reducing cell growth in different cancer lines, prompting the conclusion that the anticancer efficacy of CX-4945, the commonly used clinical-grade CK2 inhibitor, is to be attributed to its off-target effects. Here we perform a detailed scrutiny of published studies on CK2 targeting and a more in-depth analysis of the available data on SGC-CK2-1 vs. CX-4945 efficacy, providing a different perspective about the actual reliance of cancer cells on CK2. Collectively taken, our arguments would indicate that the pretended dispensability of CK2 in cancer is far from having been proved and warn against premature conclusions, which could discourage ongoing investigations on a potentially valuable drug target.

CX-4945 and siRNA-Mediated Knockdown of CK2 Improves Cisplatin Response in HPV(+) and HPV(-) HNSCC Cell Lines

Head and neck squamous cell carcinoma (HNSCC) can be categorized into human papillomavirus (HPV) positive or negative disease. Elevated protein kinase CK2 level and activity have been historically observed in HNSCC cells. Previous studies on CK2 in HNSCC did not generally include consideration of HPV(+) and HPV(−) status. Here, we investigated the response of HPV(+) and HPV(−) HNSCC cells to CK2 targeting using CX-4945 or siRNA downregulation combined with cisplatin treatment. HNSCC cell lines were examined for CK2 expression levels and activity and response to CX-4945, with and without cisplatin. CK2 levels and NFκB p65-related activity were high in HPV(+) HNSCC cells relative to HPV(−) HNSCC cells. Treatment with CX-4945 decreased viability and cisplatin IC50 in all cell lines. Targeting of CK2 increased tumor suppressor protein levels for p21 and PDCD4 in most instances. Further study is needed to understand the role of CK2 in HPV(+) and HPV(−) HNSCC and to determine how incorporation of the CK2-targeted inhibitor CX-4945 could improve cisplatin response in HNSCC.

Dalhat M, Abdullah O, Kaleem M, Hosawi S, A Al-Abbasi F, Wu W, Choudhry H, Alhosin M. Targeting Post-Translational Modifications of the p73 Protein: A Promising Therapeutic Strategy for Tumors

The tumor suppressor p73 is a member of the p53 family and is expressed as different isoforms with opposing properties. The TAp73 isoforms act as tumor suppressors and have pro-apoptotic effects, whereas the ΔNp73 isoforms lack the N-terminus transactivation domain and behave as oncogenes. The TAp73 protein has a high degree of similarity with both p53 function and structure, and it induces the regulation of various genes involved in the cell cycle and apoptosis. Unlike those of the p53 gene, the mutations in the p73 gene are very rare in tumors. Cancer cells have developed several mechanisms to inhibit the activity and/or expression of p73, from the hypermethylation of its promoter to the modulation of the ratio between its pro- and anti-apoptotic isoforms. The p73 protein is also decorated by a panel of post-translational modifications, including phosphorylation, acetylation, ubiquitin proteasomal pathway modifications, and small ubiquitin-related modifier (SUMO)ylation, that regulate its transcriptional activity, subcellular localization, and stability. These modifications orchestrate the multiple anti-proliferative and pro-apoptotic functions of TAp73, thereby offering multiple promising candidates for targeted anti-cancer therapies. In this review, we summarize the current knowledge of the different pathways implicated in the regulation of TAp73 at the post-translational level. This review also highlights the growing importance of targeting the post-translational modifications of TAp73 as a promising antitumor strategy, regardless of p53 status.

Protein kinase CK2 inhibition as a pharmacological strategy

CK2 is a constitutively active Ser/Thr protein kinase which phosphorylates hundreds of substrates. Since they are primarily related to survival and proliferation pathways, the best-known pathological roles of CK2 are in cancer, where its targeting is currently being considered as a possible therapy. However, CK2 activity has been found instrumental in many other human pathologies, and its inhibition will expectably be extended to different purposes in the near future. Here, after a description of CK2 features and implications in diseases, we analyze the different inhibitors and strategies available to target CK2, and update the results so far obtained by their in vivo application.

Myeloid Cell CK2 Regulates Inflammation and Resistance to Bacterial Infection

Kinase activity plays an essential role in the regulation of immune cell defenses against pathogens. The protein kinase CK2 (formerly casein kinase II) is an evolutionarily conserved kinase with hundreds of identified substrates. CK2 is ubiquitously expressed in somatic and immune cells, but the roles of CK2 in regulation of immune cell function remain largely elusive. This reflects the essential role of CK2 in organismal development and limited prior work with conditional CK2 mutant murine models. Here, we generated mice with a conditional (floxed) allele of Csnk2a, which encodes the catalytic CK2α subunit of CK2. When crossed to Lyz2-cre mice, excision of Csnk2a sequence impaired CK2α expression in myeloid cells but failed to detectably alter myeloid cell development. By contrast, deficiency for CK2α increased inflammatory myeloid cell recruitment, activation, and resistance following systemic Listeria monocytogenes (Lm) infection. Results from mixed chimera experiments indicated that CK2α deficiency in only a subset of myeloid cells was not sufficient to reduce bacterial burdens. Nor did cell-intrinsic deficiency for CK2α suffice to alter accumulation or activation of monocytes and neutrophils in infected tissues. These data suggest that CK2α expression by Lyz2-expressing cells promotes inflammatory and anti-bacterial responses through effects in trans. Our results highlight previously undescribed suppressive effects of CK2 activity on inflammatory myeloid cell responses and illustrate that cell-extrinsic effects of CK2 can shape inflammatory and protective innate immune responses.

Progress in Drug and Formulation Development for the Chemoprevention of Oral Squamous Cell Carcinoma: A Review

BACKGROUND

Cancer is a life-threatening global problem with high incidence rates. Prioritizing the prevention of cancer, chemopreventive agents have drawn much attention from the researchers.

OBJECTIVE

This review focuses on the discussion of the progress in the development of chemopreventive agents and formulations related to the prevention of oral cancer.

METHODS

In this perspective, an extensive literature survey was carried out to understand the mechanism, control and chemoprevention of oral cancer. Different patented agents and formulations have also exhibited cancer preventive efficacy in experimental studies. This review summarizes the etiology of oral cancer and developments in prevention strategies.

RESULTS

The growth of oral cancer is a multistep activity necessitating the accumulation of genetic as well as epigenetic alterations in key regulatory genes. Many risk factors are associated with oral cancer. Genomic technique for sequencing all tumor specimens has been made available to help detect mutations. The recent development of molecular pathway and genetic tools has made the process of diagnosis easier, better forecast and efficient therapeutic management. Different chemical agents have been studied for their efficacy to prevent oral cancer and some of them have shown promising results.

CONCLUSION

Use of chemopreventive agents, either synthetic or natural origin, to prevent carcinogenesis is a worthy concept in the management of cancers. Preventive measures are helpful in controlling the occurrence or severity of the disease. The demonstrated results of preventive agents have opened an arena for the development of promising chemopreventive agents in the management of oral squamous cell carcinoma.

Tumor necrosis factor α-induced protein 1 as a novel tumor suppressor through selective downregulation of CSNK2B blocks nuclear factor-κB activation in hepatocellular carcinoma

Background

Tumor necrosis factor α-induced protein 1 (TNFAIP1) is frequently downregulated in cancer cell lines and promotes cancer cell apoptosis. However, its role, clinical significance and molecular mechanisms in hepatocellular carcinoma (HCC) are unknown.

Methods

The expression of TNFAIP1 in HCC tumor tissues and cell lines was measured by Western blot and immunohistochemistry. The effects of TNFAIP1 on HCC proliferation, apoptosis, metastasis, angiogenesis and tumor formation were evaluated by Cell Counting Kit-8 (CCK8), Terminal deoxynucleotidyl transferase dUTP Nick-End Labeling (TUNEL), transwell, tube formation assay in vitro and nude mice experiments in vivo. The interaction between TNFAIP1 and CSNK2B was validated by liquid chromatography-tandem mass spectrometry (LC-MS/MS), Co-immunoprecipitation and Western blot. The mechanism of how TNFAIP1 regulated nuclear factor-kappaB (NF-κB) pathway was analyzed by dual-luciferase reporter, immunofluorescence, quantitative Real-time polymerase chain reaction (RT-qPCR) and Western blot.

Findings

The TNFAIP1 expression is significantly decreased in HCC tissues and cell lines, and negatively correlated with the increased HCC histological grade. Overexpression of TNFAIP1 inhibits HCC cell proliferation, metastasis, angiogenesis and promotes cancer cell apoptosis both in vitro and in vivo, whereas the knockdown of TNFAIP1 in HCC cell displays opposite effects. Mechanistically, TNFAIP1 interacts with CSNK2B and promotes its ubiquitin-mediated degradation with Cul3, causing attenuation of CSNK2B-dependent NF-κB trans-activation in HCC cell. Moreover, the enforced expression of CSNK2B counteracts the inhibitory effects of TNFAIP1 on HCC cell proliferation, migration, and angiogenesis in vitro and in vivo.

Interpretation

Our results support that TNFAIP1 can act as a tumor suppressor of HCC by modulating TNFAIP1/CSNK2B/NF-κB pathway, implying that TNFAIP1 may represent a potential marker and a promising therapeutic target for HCC.

Protein Kinase CK2 Subunits Differentially Perturb the Adhesion and Migration of GN11 Cells: A Model of Immature Migrating Neurons

Protein kinase CK2 (CK2) is a highly conserved and ubiquitous kinase is involved in crucial biological processes, including proliferation, migration, and differentiation. CK2 holoenzyme is a tetramer composed by two catalytically active (α/α’) and two regulatory (β) subunits and exerts its function on a broad range of targets. In the brain, it regulates different steps of neurodevelopment, such as neural differentiation, neuritogenesis, and synaptic plasticity. Interestingly, CK2 mutations have been recently linked to neurodevelopmental disorders; however, the functional requirements of the individual CK2 subunits in neurodevelopment have not been yet investigated. Here, we disclose the role of CK2 on the migration and adhesion properties of GN11 cells, an established model of mouse immortalized neurons, by different in vitro experimental approaches. Specifically, the cellular requirement of this kinase has been assessed pharmacologically and genetically by exploiting CK2 inhibitors and by generating subunit-specific CK2 knockout GN11 cells (with a CRISPR/Cas9-based approach). We show that CK2α’ subunit has a primary role in increasing cell adhesion and reducing migration properties of GN11 cells by activating the Akt-GSK3β axis, whereas CK2α subunit is dispensable. Further, the knockout of the CK2β regulatory subunits counteracts cell migration, inducing dramatic alterations in the cytoskeleton not observed in CK2α’ knockout cells. Collectively taken, our data support the view that the individual subunits of CK2 play different roles in cell migration and adhesion properties of GN11 cells, supporting independent roles of the different subunits in these processes.

CK2 Pro-Survival Role in Prostate Cancer Is Mediated via Maintenance and Promotion of Androgen Receptor and NFκB p65 Expression

The prosurvival protein kinase CK2, androgen receptor (AR), and nuclear factor kappa B (NFκB) interact in the function of prostate cells, and there is evidence of crosstalk between these signals in the pathobiology of prostate cancer (PCa). As CK2 is elevated in PCa, and AR and NFκB are involved in the development and progression of prostate cancer, we investigated their interaction in benign and malignant prostate cells in the presence of altered CK2 expression. Our results show that elevation of CK2 levels caused increased levels of AR and NFκB p65 in prostate cells of different phenotypes. Analysis of TCGA PCa data indicated that AR and CK2α RNA expression are strongly correlated. Small molecule inhibition or molecular down-regulation of CK2 caused reduction in AR mRNA expression and protein levels in PCa cells and in orthotopic xenograft tumors by various pathways. Among these, regulation of AR protein stability plays a unifying role in CK2 maintenance of AR protein levels. Our results show induction of various endoplasmic reticulum stress signals after CK2 inhibition, which may play a role in the PCa cell death response. Of note, CK2 inhibition caused loss of cell viability in both parental and enzalutamide-resistant castrate-resistant PCa cells. The present work elucidates the specific link of CK2 to the pathogenesis of PCa in association with AR and NFκB expression; further, the observation that inhibition of CK2 can exert a growth inhibitory effect on therapy-resistant PCa cells emphasizes the potential utility of CK2 inhibition in patients who are on enzalutamide treatment for advanced cancer.

The Combination of the CIGB-300 Anticancer Peptide and Cisplatin Modulates Proteins Related to Cell Survival, DNA Repair and Metastasis in a Lung Cancer Cell Line Model

Background:

CIGB-300 is a pro-apoptotic peptide that abrogates CK2-mediated phosphorylation, and can elicit synergistic interaction in vitro and in vivo when combined with certain anticancer drugs.

Objective:

The combination of CIGB-300 with cisplatin is studied through data mining and expressionbased proteomics to reveal the molecular basis of this interaction. Cisplatin resistance-associated proteins, which have also been reported as CK2 substrates, were first identified by bioinformatic analyses.

Methods:

Data from these analyses suggested that the cisplatin resistance phenotype could be directly improved by inhibiting CK2 phosphorylation on specific substrates. Furthermore, 157 proteins were differentially modulated on the NCI-H125 lung cancer cell line in response to CIGB-300, cisplatin or both drugs as determined by LC-MS/MS.

Results:

The expression of 28 cisplatin resistance-associated proteins was changed when cisplatin was combined with CIGB-300. Overall, the proteins identified are also related to cell survival, cell proliferation and metastasis. Furthermore, the CIGB-300 regulated proteome revealed proteins that were initially involved in the mechanism of action of CIGB-300 and cisplatin as single agents.

Conclusion:

This is the first report describing the protein array modulated by combining CIGB-300 and cisplatin that will support the rationale for future clinical settings based on a multi-target cancer therapy.

Protein Kinase CK2, a Potential Therapeutic Target in Carcinoma Management

The Protein kinase CK2 (formerly known as casein kinase 2) is a highly conserved serine/ threonine kinase overexpressed in various human carcinomas and its high expression often correlates with poor prognosis. CK2 protein is localized in the nucleus of many tumor cells and correlates with clinical features in many cases. Increased expression of CK2 in mice results in the development of various types of carcinomas (both solids and blood related tumors, such as (breast carcinoma, lymphoma, etc), which reveals its carcinogenic properties. CK2 plays essential roles in many key biological processes related to carcinoma, including cell apoptosis, DNA damage responses and cell cycle regulation. CK2 has become a potential anti-carcinoma target. Various CK2 inhibitors have been developed with anti-neoplastic properties against a variety of carcinomas. Some CK2 inhibitors have showed good results in in vitro and pre-clinical models, and have even entered in clinical trials. This article will review effects of CK2 and its inhibitors on common carcinomas in in vitro and pre-clinical studies.

Biochemical Characterization of Ferulic Acid and Caffeic Acid Which Effectively Inhibit Melanin Synthesis via Different Mechanisms in B16 Melanoma Cells

In this study, we examined the inhibitory effects of ferulic acid and caffeic acid on melanin production using a murine B16 melanoma cell line. The mechanisms by which the two acids inhibit melanin production were investigated by evaluating their effects on the activity of tyrosinase, which is involved is the first step of melanin biosynthesis. Ferulic acid showed no toxicity against the melanoma cells at any dose, whereas caffeic acid exerted cellular toxicity at concentrations higher than 0.35 mM. Both ferulic and caffeic acids effectively inhibited melanin production in the B16 melanoma cells. Ferulic acid reduced tyrosinase activity by directly binding to the enzyme, whereas no binding was observed between caffeic acid and tyrosinase. Both ferulic acid and caffeic acid inhibited casein kinase 2 (CK2)-induced phosphorylation of tyrosinase in a dose-dependent manner in vitro. Ferulic acid was found to be a more effective inhibitor of melanin production than caffeic acid; this difference in the inhibitory efficacy between the two substances could be attributable to the difference in their tyrosine-binding activity. Our analysis revealed that both substances also inhibited the CK2-mediated phosphorylation of tyrosinase.

CIGB-300: A peptide-based drug that impairs the Protein Kinase CK2-mediated phosphorylation

Protein kinase CK2, formerly referred to as casein kinase II, is a serine/threonine kinase often found overexpressed in solid tumors and hematologic malignancies that phosphorylates many substrates integral to the hallmarks of cancer. CK2 has emerged as a viable oncology target having been experimentally validated with different kinase inhibitors, including small molecule ATP-competitors, synthetic peptides, and antisense oligonucleotides. To date only two CK2 inhibitors, CIGB-300 and CX-4945, have entered the clinic in phase 1-2 trials. This review provides information on CIGB-300, a cell-permeable cyclic peptide that inhibits CK2-mediated phosphorylation by targeting the substrate phosphoacceptor domain. We review data that support the concept of CK2 as an anticancer target, address the mechanism of action, and summarize preclinical studies showing antiangiogenic and antimetastatic effects as well as synergism with anticancer drugs in preclinical models. We also summarize early clinical research (phase 1/2 trials) of CIGB-300 in cervical cancer, including data in combination with chemoradiotherapy. The clinical data demonstrate the safety, tolerability, and clinical effects of intratumoral injections of CIGB-300 and provide the foundation for future phase 3 clinical trials in locally advanced cervical cancer in combination with standard chemoradiotherapy.

CK2 targeted RNAi therapeutic delivered via malignant cell-directed tenfibgen nanocapsule: dose and molecular mechanisms of response in xenograft prostate tumors

CK2, a protein serine/threonine kinase, promotes cell proliferation and suppresses cell death. This essential-for-survival signal demonstrates elevated expression and activity in all cancers examined, and is considered an attractive target for cancer therapy. Here, we present data on the efficacy of a tenfibgen (TBG) coated nanocapsule which delivers its cargo of siRNA (siCK2) or single stranded RNA/DNA oligomers (RNAi-CK2) simultaneously targeting CK2α and α' catalytic subunits. Intravenous administration of TBG-siCK2 or TBG-RNAi-CK2 resulted in significant xenograft tumor reduction at low doses in PC3-LN4 and 22Rv1 models of prostate cancer. Malignant cell uptake and specificity in vivo was verified by FACS analysis and immunofluorescent detection of nanocapsules and PCR detection of released oligomers. Dose response was concordant with CK2αα' RNA transcript levels and the tumors demonstrated changes in CK2 protein and in markers of proliferation and cell death. Therapeutic response corresponded to expression levels for argonaute and GW proteins, which function in oligomer processing and translational repression. No toxicity was detected in non-tumor tissues or by serum chemistry. Tumor specific delivery of anti-CK2 RNAi via the TBG nanoencapsulation technology warrants further consideration of translational potential.

CK2α promotes advanced glycation end products-induced expressions of fibronectin and intercellular adhesion molecule-1 via activating MRTF-A in glomerular mesangial cells

Advanced glycation end products' (AGEs) modification of extracellular matrix proteins induces crosslinking, which results in thickening of the basement membrane and activating several intracellular signaling cascades, eventually promoting the pathological progression of diabetic nephropathy (DN). We have previously confirmed that casein kinase 2α (CK2α) activates the nuclear factor of kappaB (NF-κB) signaling pathway to enhance high glucose-induced expressions of fibronectin (FN) and intercellular adhesion molecule-1 (ICAM-1) in glomerular mesangial cells (GMCs). However, to date, the mechanism by which CK2α regulates diabetic renal fibrosis is not fully understood. In view of the regulation of inflammation and fibrosis by myocardin-related transcription factor A (MRTF-A), we are highly concerned whether CK2α promotes AGEs-induced expressions of FN and ICAM-1 in glomerular mesangial cells via activation of MRTF-A, thus affecting the pathogenesis of DN. We found that CK2α and MRTF-A proteins were overexpressed in AGEs-induced diabetic kidneys. Inhibition of CK2α kinase activity or knockdown of CK2α protein expression suppressed the upregulation of FN and ICAM-1 expressions in GMCs induced by AGEs. MRTF-A knockdown compromised the expressions of FN and ICAM-1 in GMCs induced by AGEs. Moreover, inhibition of CK2α kinase activity or knockdown of CK2α protein expression restrained the protein expression and nuclear aggregation of MRTF-A. CK2α interacted with MRTF-A. Furthermore, knockdown of MRTF-A while overexpression of CK2α blocked the upregulation effect of CK2α on the protein expressions of FN and ICAM-1. These findings suggest that CK2α promotes diabetic renal fibrosis via activation of MRTF-A and upregulation of inflammatory genes.

Cancer-type dependent expression of CK2 transcripts

A multitude of proteins are aberrantly expressed in cancer cells, including the oncogenic serine-threonine kinase CK2. In a previous report, we found increases in CK2 transcript expression that could explain the increased CK2 protein levels found in tumors from lung and bronchus, prostate, breast, colon and rectum, ovarian and pancreatic cancers. We also found that, contrary to the current notions about CK2, some CK2 transcripts were downregulated in several cancers. Here, we investigate all other cancers using Oncomine to determine whether they also display significant CK2 transcript dysregulation. As anticipated from our previous analysis, we found cancers with all CK2 transcripts upregulated (e.g. cervical), and cancers where there was a combination of upregulation and/or downregulation of the CK2 transcripts (e.g. sarcoma). Unexpectedly, we found some cancers with significant downregulation of all CK2 transcripts (e.g. testicular cancer). We also found that, in some cases, CK2 transcript levels were already dysregulated in benign lesions (e.g. Barrett’s esophagus). We also found that CK2 transcript upregulation correlated with lower patient survival in most cases where data was significant. However, there were two cancer types, glioblastoma and renal cell carcinoma, where CK2 transcript upregulation correlated with higher survival. Overall, these data show that the expression levels of CK2 genes is highly variable in cancers and can lead to different patient outcomes.

Evaluation of protein kinase CK2 as a therapeutic target for squamous cell carcinoma of cats

OBJECTIVE To investigate protein kinase CK2 (CK2) expression in squamous cell carcinoma (SCC) of cats and to examine effects of CK2 downregulation on in vitro apoptosis and viability in SCC. SAMPLE Biopsy specimens of oral mucosa and testis and blood samples from clinically normal cats, biopsy specimens of oral SCC from cats, and feline SCC (SCCF1) and mammary gland carcinoma (K12) cell lines. PROCEDURES Immunohistochemical labeling for CK2α was performed on biopsy specimens. Sequences of the CK2α subunit gene and CK2α' subunit gene in feline blood and feline cancer cell lines were determined by use of PCR and reverse-transcription PCR assays followed by direct Sanger sequencing. Specific small interfering RNAs (siRNAs) were developed for feline CK2α and CK2α'. The SCCF1 cells were treated with siRNA and assessed 72 hours later for CK2α and CK2α' expression and markers of apoptosis (via western blot analysis) and for viability (via 3-[4,5-dimethylthiazol-2-yl]-5-[3-carboxymethoxyphenyl]-2-[4-sulfophenyl]-2H-tetrazolium assays). RESULTS CK2α was expressed in all feline oral mucosa samples and 7 of 8 oral SCC samples. Expression of CK2α and CK2α' was successfully downregulated in SCCF1 cells by use of siRNAs, which resulted in decreased viability and induction of apoptosis. CONCLUSIONS AND CLINICAL RELEVANCE In this study, CK2 appeared to be a promising therapeutic target for SCCs of cats. A possible treatment strategy for SCCs of cats would be RNA interference that targets CK2.

Targeted nanoparticles for head and neck cancers: overview and perspectives

Head and neck cancer (HNC) is common in several regions and is associated with high morbidity and mortality worldwide. This review summarizes the recent progress in the development of targeted nanoparticle systems for HNC therapy. WIREs Nanomed Nanobiotechnol 2017, 9:e1469. doi: 10.1002/wnan.1469 For further resources related to this article, please visit the WIREs website.

Therapeutic Targeting of Protein Kinase CK2 Gene Expression in Feline Oral Squamous Cell Carcinoma: A Naturally Occurring Large-Animal Model of Head and Neck Cancer

Protein kinase CK2 (CK2) is a highly promising target for cancer therapy, and anti-CK2 gene expression therapy has shown effectiveness in rodent models of human head and neck cancer (HNC). To date, there has been no large-animal model of cancer in which to further explore anti-CK2 therapies. Feline oral squamous cell carcinoma (FOSCC) has been proposed as a large-animal model for human HNC, and we have previously shown that CK2 is a rational target in FOSCC. Here we have tested the hypothesis that a novel tenfibgen-coated tumor-specific nanocapsule carrying RNA interference (RNAi) oligonucleotides targeting feline CK2α and CK2α' (TBG-RNAi-fCK2αα') would be safe in cats with FOSCC; assessment of target inhibition and tumor response were secondary aims. Nine cats were enrolled and treated at two dose levels in a 3+3 escalation. Cats received a total of six treatments with TBG-RNAi-fCK2αα'. Pre- and posttreatment, tumor and normal oral mucosa biopsies were collected to assess CK2 expression, using immunohistochemistry (IHC) preparations evaluated by light microscopy. Toxicity and tumor response were assessed on the basis of standard criteria. The most common adverse events were grade 1 or 2 weight loss and anorexia. Grade 3 tissue necrosis was seen in association with tumor response in one cat, asymptomatic grade 4 elevations in aspartate transaminase and creatine phosphokinase in one cat, and asymptomatic grade 3 hypokalemia in one cat. Of six cats with evaluable biopsies, two had a reduction in CK2 IHC score in tumors after treatment. Four cats had progressive disease during the study period, three had stable disease, one had partial response, and response could not be evaluated in one cat. We conclude that the drug appeared safe and that there is some evidence of efficacy in FOSCC. Further investigation regarding dosing, schedule, target modulation, toxicity, and efficacy in a larger group of cats is warranted and may inform future clinical studies in human head and neck cancer.

Can gene editing and silencing technologies play a role in the treatment of head and neck cancer?

Conventional treatment strategies have done little to improve the prognosis or disease-free survival in head and neck cancer (HNC) patients. Recent progress in our understanding of molecular aspects of head and neck squamous cell carcinoma (HNSCC) has provided insights into the potential use of molecular targeted therapies in combination with current treatment strategies. Here we review the current understanding of treatment modalities for both HPV-positive and HPV-negative HNSCCs with the potential to use gene editing and silencing technologies therapeutically. The development of sequence-specific RNA interference (RNAi) with its strong gene-specific silencing ability, high target specificity, greater potency and reduced side effects, has shown it to be a promising therapeutic candidate for treating cancers. CRISPR/Cas gene editing is the newest technology with the ability to delete, mutate or replace genes of interest and has great potential for treating HNSCCs. We also discuss the major challenge in using these approaches in HNSCC; that being the choice of target and the ability to deliver the payload. Finally, we highlight the potential combination of RNAi or CRIPSR/Cas with current treatment strategies and outline the possible path to the clinic.

CK2 Molecular Targeting-Tumor Cell-Specific Delivery of RNAi in Various Models of Cancer

Protein kinase CK2 demonstrates increased protein expression relative to non-transformed cells in the majority of cancers that have been examined. The elevated levels of CK2 are involved in promoting not only continued proliferation of cancer cells but also their resistance to cell death; thus, CK2 has emerged as a plausible target for cancer therapy. Our focus has been to target CK2 catalytic subunits at the molecular level using RNA interference (RNAi) strategies to achieve their downregulation. The delivery of oligonucleotide therapeutic agents warrants that they are protected and are delivered specifically to cancer cells. The latter is particularly important since CK2 is a ubiquitous signal that is essential for survival. To achieve these goals, we have developed a nanocapsule that has the properties of delivering an anti-CK2 RNAi therapeutic cargo, in a protected manner, specifically to cancer cells. Tenfibgen (TBG) is used as the ligand to target tenascin-C receptors, which are elevated in cancer cells. This strategy is effective for inhibiting growth and inducing death in several types of xenograft tumors, and the nanocapsule elicits no safety concerns in animals. Further investigation of this therapeutic approach for its translation is warranted.

CK2 in Cancer: Cellular and Biochemical Mechanisms and Potential Therapeutic Target

CK2 genes are overexpressed in many human cancers, and most often overexpression is associated with worse prognosis. Site-specific expression in mice leads to cancer development (e.g., breast, lymphoma) indicating the oncogenic nature of CK2. CK2 is involved in many key aspects of cancer including inhibition of apoptosis, modulation of signaling pathways, DNA damage response, and cell cycle regulation. A number of CK2 inhibitors are now available and have been shown to have activity against various cancers in vitro and in pre-clinical models. Some of these inhibitors are now undergoing exploration in clinical trials as well. In this review, we will examine some of the major cancers in which CK2 inhibition has promise based on in vitro and pre-clinical studies, the proposed cellular and signaling mechanisms of anti-cancer activity by CK2 inhibitors, and the current or recent clinical trials using CK2 inhibitors.

Increased expression of protein kinase CK2α correlates with poor patient prognosis in epithelial ovarian cancer

Epithelial ovarian cancer (EOC) is one of the deadly gynecological malignancies. The function of protein kinase CK2α (CK2α) in EOC is still unknown. Our study aimed to investigate the relationship between the protein expression of CK2α and the tumor progression, the prognosis of human EOC. In this study, we analyzed the expression levels of CK2α through Western blot, using EOC cell lines like A2780, HO8910, COV644, OVCAR3, SKOV3, and the primary normal ovarian surface epithelial (NOSE) cells. Furthermore, OVCAR3 and SKOV3 EOC cells were employed as a cellular model to study the role of CK2α on cell growth, migration, invasion, apoptosis, and cell cycle distribution. In addition, we investigated CK2α protein expression in tumor tissues from patients with EOC by immunohistochemistry and analyzed the association between CK2α expression and clinicopathologic parameters and prognosis of EOC patients. And we found that compared with NOSE cells, CK2α protein expression was increased in A2780, HO8910, OVCAR3, and SKOV3 ovarian cancer cell lines. Decreased CK2α expression suppressed OVCAR3 and SKOV3 cell growth and induced more apoptosis. CK2α knockdown using specific siRNAs inhibited migration and invasion ability of OVCAR3 and SKOV3 cells. In addition, high CK2α protein expression was found in 68.4% (80/117) of EOC patients. Increased CK2α expression of was significantly correlated with FIGO staging and peritoneal cytology. Patients with higher CK2α expression had a significantly poorer overall survival compared with those with lower CK2α expression. Multi-variate Cox regression analysis proved that increased CK2α expression was an independent prognostic marker for EOC. Taken together, our data displayed that CK2α may play a role in tumor aggressive behavior of EOC and could be used as a marker for predicting prognosis of EOC patient. High CK2α expression might predict poor patient survival.

Protein kinase CK2α catalytic subunit is overexpressed and serves as an unfavorable prognostic marker in primary hepatocellular carcinoma

Protein kinase CK2 alpha (CK2α), one isoform of the catalytic subunit of serine/threonine kinase CK2, has been indicated to participate in tumorigenesis of various malignancies. We conducted this study to investigate the biological significances of CK2α expression in hepatocellular carcinoma (HCC) development. Real-time quantitative polymerase and western blotting analyses revealed that CK2α expression was significantly increased at mRNA and protein levels in HCC tissues. Immunohistochemical analyses indicated that amplified expression of CK2α was highly correlated with poor prognosis. And functional analyses (cell proliferation and colony formation assays, cell migration and invasion assays, cell cycle and apoptosis assays) found that CK2α promoted cell proliferation, colony formation, migration and invasion, as well as inhibited apoptosis in hepatoma cell lines in vitro. CK2α-silenced resulted in significant apoptosis in cells that was demonstrated been associated with downregulation of expression of Bcl-2, p-AKT (ser473) and upregulation of expression of total P53, p-P53, Bax, caspase3 and cleaved-caspase3 in HCC cells. In addition, experiments with a mouse model revealed that the stimulative effect of CK2α on tumorigenesis in nude mice. Our results suggest that CK2α might play an oncogenic role in HCC, and therefore it could serve as a biomarker for prognostic and therapeutic applications in HCC.

Novel Anthra[1,2-c][1,2,5]Thiadiazole-6,11-Diones as Promising Anticancer Lead Compounds: Biological Evaluation, Characterization & Molecular Targets Determination

The novel compounds NSC745885 and NSC757963 developed at our laboratory were tested against a panel of 60 cancer cell lines at the National Cancer Institute, USA, and a panel of 39 cancer cell lines at the Japanese Foundation of Cancer Research. Both compounds demonstrated selective unique multi-log differential patterns of activity, with GI₅₀ values in the sub-micro molar range against cancer cells rather than normal cardiac cells. NSC757963 showed high selectivity towards the leukemia subpanel. Activities of both compounds strongly correlated to expression of NFKB1 and CSNK2B genes, implying that they may inhibit the NF-κB pathway. Immunocytochemical microscopy of OVCAR-3 cells showed clear cytosolic accumulation of the NF-κB p65 subunit following treatment. Western blotting showed dose dependent inhibition of the nuclear expression of the NF-κB p65 subunit with subsequent accumulation in the cytosol following treatment. Docking experiments showed binding of both compounds to the NF-κB activator IKKβ subunit preventing its translocation to the nucleus. Collectively, these results confirm the ability of our compounds to inhibit the constitutively active NF-κB pathway of OVCAR-3 cells. Furthermore, COMPARE analysis indicated that the activity of NSC757963 is similar to the antituberculosis agent rifamycin SV, this was confirmed by testing the antimycobacterial activity of NSC757963 against Mycobacterium tuberculosis, results revealed potent activity suitable for use in clinical practice. Molecular properties and Lipinski’s parameters predicted acceptable bioavailability properties with no indication of mutagenicity, tumorigenicity, irritability and reproductive effects. Oral absorption experiments using the human Caco-2 model showed high intestinal absorption of NSC745885 by passive transport mechanism with no intestinal efflux or active transport mechanisms. The unique molecular characterization as well as the illustrated anticancer spectra of activity and bioavailability properties warrant further development of our compounds and present a foundation brick in the pre-clinical investigations to implement such compounds in clinical practice.

CK2 inhibition induced PDK4-AMPK axis regulates metabolic adaptation and survival responses in glioma

Understanding mechanisms that link aberrant metabolic adaptation and pro-survival responses in glioma cells is crucial towards the development of new anti-glioma therapies. As we have previously reported that CK2 is associated with glioma cell survival, we evaluated its involvement in the regulation of glucose metabolism. Inhibition of CK2 increased the expression of metabolic regulators, PDK4 and AMPK along with the key cellular energy sensor CREB. This increase was concomitant with altered metabolic profile as characterized by decreased glucose uptake in a PDK4 and AMPK dependent manner. Increased PDK4 expression was CREB dependent, as exogenous inhibition of CREB functions abrogated CK2 inhibitor mediated increase in PDK4 expression. Interestingly, PDK4 regulated AMPK phosphorylation which in turn affected cell viability in CK2 inhibitor treated glioma cells. CK2 inhibitor 4,5,6,7-Tetrabromobenzotriazole (TBB) significantly retarded the growth of glioma xenografts in athymic nude mouse model. Coherent with the in vitro findings, elevated senescence, pAMPK and PDK4 levels were also observed in TBB-treated xenograft tissue. Taken together, CK2 inhibition in glioma cells drives the PDK4-AMPK axis to affect metabolic profile that has a strong bearing on their survival.

Casein kinases as potential therapeutic targets

INTRODUCTION

The conventional term 'casein kinase' (CK) denotes three classes of kinases - CK1, CK2 and Golgi-CK (G-CK)/Fam20C (family with sequence similarity 20, member C) - sharing the ability to phoshorylate casein in vitro, but otherwise unrelated to each other. All CKs have been reported to be implicated in human diseases, and reviews individually dealing with the druggability of CK1 and CK2 are available. Our aim is to provide a comparative analysis of the three classes of CKs as therapeutic targets.

AREAS COVERED

CK2 is the CK for which implication in neoplasia is best documented, with the survival of cancer cells often relying on its overexpression. An ample variety of cell-permeable CK2 inhibitors have been developed, with a couple of these now in clinical trials. Isoform-specific CK1 inhibitors that are expected to play a beneficial role in oncology and neurodegeneration have been also developed. In contrast, the pathogenic potential of G-CK/Fam20C is caused by its loss of function. Activators of Fam20C, notably sphingolipids and their analogs, may prove beneficial in this respect.

EXPERT OPINION

Optimization of CK2 and CK1 inhibitors will prove useful to develop new therapeutic strategies for treating cancer and neurodegenerative disorders, while the design of potent activators of G-CK/Fam20C will provide a new tool in the fields of bio-mineralization and hypophosphatemic diseases.

MEK inhibitor PD-0325901 overcomes resistance to CK2 inhibitor CX-4945 and exhibits anti-tumor activity in head and neck cancer

The serine-threonine kinase CK2 exhibits genomic alterations and aberrant overexpression in human head and neck squamous cell carcinomas (HNSCC). Here, we investigated the effects of CK2 inhibitor CX-4945 in human HNSCC cell lines and xenograft models. The IC_50's of CX-4945 for 9 UM-SCC cell lines measured by MTT assay ranged from 3.4-11.9 μM. CX-4945 induced cell cycle arrest and cell death measured by DNA flow cytometry, and inhibited prosurvival mediators phospho-AKT and p-S6 in UM-SCC1 and UM-SCC46 cells. CX-4945 decreased NF-κB and Bcl-XL reporter gene activities in both cell lines, but upregulated proapoptotic TP53 and p21 reporter activities, and induced phospho-ERK, AP-1, and IL-8 activity in UM-SCC1 cells. CX-4945 exhibited modest anti-tumor activity in UM-SCC1 xenografts. Tumor immunostaining revealed significant inhibition of PI3K-Akt-mTOR pathway and increased apoptosis marker TUNEL, but also induced p-ERK, c-JUN, JUNB, FOSL1 and proliferation (Ki67) markers, as a possible resistance mechanism. To overcome the drug resistance, we tested MEK inhibitor PD-0325901 (PD-901), which inhibited ERK-AP-1 activation alone and in combination with CX-4945. PD-901 alone displayed significant anti-tumor effects in vivo, and the combination of PD-901 and CX-4945 slightly enhanced anti-tumor activity when compared with PD-901 alone. Immunostaining of tumor specimens after treatment revealed inhibition of p-AKT S129 and p-AKT T308 by CX-4945, and inhibition of p-ERK T202/204 and AP-1 family member FOSL-1 by PD-901. Our study reveals a drug resistance mechanism mediated by the MEK-ERK-AP-1 pathway in HNSCC. MEK inhibitor PD-0325901 is active in HNSCC resistant to CX-4945, meriting further clinical investigation.

Preclinical evaluation of cyclin dependent kinase 11 and casein kinase 2 survival kinases as RNA interference targets for triple negative breast cancer therapy

Introduction

Targeted therapies for aggressive breast cancers like triple negative breast cancer (TNBC) are needed. The use of small interfering RNAs (siRNAs) to disable expression of survival genes provides a tool for killing these cancer cells. Cyclin dependent kinase 11 (CDK11) is a survival protein kinase that regulates RNA transcription, splicing and mitosis. Casein kinase 2 (CK2) is a survival protein kinase that suppresses cancer cell death. Eliminating the expression of these genes has potential therapeutic utility for breast cancer.

Methods

Expression levels of CDK11 and CK2 mRNAs and associated proteins were examined in breast cancer cell lines and tissue arrays. RNA expression levels of CDC2L1, CDC2L2, CCNL1, CCNL2, CSNK2A1, CSNK2A2, and CSNK2B genes in breast cancer subtypes were analyzed. Effects following transfection of siRNAs against CDK11 and CK2 in cultured cells were examined by viability and clonal survival assays and by RNA and protein measures. Uptake of tenfibgen (TBG) nanocapsules by TNBC cells was analyzed by fluorescence-activated cell sorting. TBG nanocapsules delivered siRNAs targeting CDK11 or CK2 in mice carrying TNBC xenograft tumors. Transcript cleavage and response parameters were evaluated.

Results

We found strong CDK11 and CK2 mRNA and protein expression in most human breast cancer cells. Immunohistochemical analysis of TNBC patient tissues showed 100% of tumors stained positive for CDK11 with high nuclear intensity compared to normal tissue. The Cancer Genome Atlas analysis comparing basal to other breast cancer subtypes and to normal breast revealed statistically significant differences. Down-regulation of CDK11 and/or CK2 in breast cancer cells caused significant loss of cell viability and clonal survival, reduced relevant mRNA and protein expression, and induced cell death changes. TBG nanocapsules were taken up by TNBC cells both in culture and in xenograft tumors. Treatment with TBG- siRNA to CDK11 or TBG- siRNA to CK2αα’ nanocapsules induced appropriate cleavage of CDK11 and CK2α transcripts in TNBC tumors, and caused MDA-MB-231 tumor reduction, loss of proliferation, and decreased expression of targeted genes.

Conclusions

CDK11 and CK2 expression are individually essential for breast cancer cell survival, including TNBC. These genes serve as promising new targets for therapeutic development in breast cancer.

Nanoparticle-based targeted therapeutics in head-and-neck cancer

Head-and-neck cancer is a major form of the disease worldwide. Treatment consists of surgery, radiation therapy and chemotherapy, but these have not resulted in improved survival rates over the past few decades. Versatile nanoparticles, with selective tumor targeting, are considered to have the potential to improve these poor outcomes. Application of nanoparticle-based targeted therapeutics has extended into many areas, including gene silencing, chemotherapeutic drug delivery, radiosensitization, photothermal therapy, and has shown much promise. In this review, we discuss recent advances in the field of nanoparticle-mediated targeted therapeutics for head-and-neck cancer, with an emphasis on the description of targeting points, including future perspectives.

Altered Transcriptional Control Networks with Trans-Differentiation of Isogenic Mutant-KRas NSCLC Models

Background: The capacity of cancer cells to undergo epithelial mesenchymal trans-differentiation has been implicated as a factor driving metastasis, through the acquisition of enhanced migratory/invasive cell programs and the engagement of anti-apoptotic mechanisms promoting drug and radiation resistance. Our aim was to define molecular signaling changes associated with mesenchymal trans-differentiation in two KRas mutant NSCLC models. We focused on central transcription and epigenetic regulators predicted to be important for mesenchymal cell survival.

Experimental design: We have modeled trans-differentiation and cancer stemness in inducible isogenic mutant-KRas H358 and A549 non-small cell lung cell backgrounds. As expected, our models show mesenchymal-like tumor cells acquire novel mechanisms of cellular signaling not apparent in their epithelial counterparts. We employed large-scale quantitative phosphoproteomic, proteomic, protein–protein interaction, RNA-Seq, and network function prediction approaches to dissect the molecular events associated with the establishment and maintenance of the mesenchymal state.

Results: Gene-set enrichment and pathway prediction indicated BMI1, KDM5B, RUNX2, MYC/MAX, NFκB, LEF1, and HIF1 target networks were significantly enriched in the trans-differentiation of H358 and A549 NSCLC models. Physical overlaps between multiple networks implicate NR4A1 as an overlapping control between TCF and NFκB pathways. Enrichment correlations also indicated marked decrease in cell cycling, which occurred early in the EMT process. RNA abundance time course studies also indicated early expression of epigenetic and chromatin regulators within 8–24 h, including CITED4, RUNX3, CMBX1, and SIRT4.

Conclusion: Multiple transcription and epigenetic pathways where altered between epithelial and mesenchymal tumor cell states, notably the polycomb repressive complex-1, HP1γ, and BAF/Swi-Snf. Network analysis suggests redundancy in the activation and inhibition of pathway regulators, notably factors controlling epithelial cell state. Through large-scale transcriptional and epigenetic cell reprograming, mesenchymal trans-differentiation can promote diversification of signaling networks potentially important in resistance to cancer therapies.

Tenfibgen ligand nanoencapsulation delivers bi-functional anti-CK2 RNAi oligomer to key sites for prostate cancer targeting using human xenograft tumors in mice

Protected and specific delivery of nucleic acids to malignant cells remains a highly desirable approach for cancer therapy. Here we present data on the physical and chemical characteristics, mechanism of action, and pilot therapeutic efficacy of a tenfibgen (TBG)-shell nanocapsule technology for tumor-directed delivery of single stranded DNA/RNA chimeric oligomers targeting CK2αα' to xenograft tumors in mice. The sub-50 nm size TBG nanocapsule (s50-TBG) is a slightly negatively charged, uniform particle of 15 - 20 nm size which confers protection to the nucleic acid cargo. The DNA/RNA chimeric oligomer (RNAi-CK2) functions to decrease CK2αα' expression levels via both siRNA and antisense mechanisms. Systemic delivery of s50-TBG-RNAi-CK2 specifically targets malignant cells, including tumor cells in bone, and at low doses reduces size and CK2-related signals in orthotopic primary and metastatic xenograft prostate cancer tumors. In conclusion, the s50-TBG nanoencapsulation technology together with the chimeric oligomer targeting CK2αα' offer significant promise for systemic treatment of prostate malignancy.

CK2 phosphorylates and inhibits TAp73 tumor suppressor function to promote expression of cancer stem cell genes and phenotype in head and neck cancer

Cancer stem cells (CSC) and genes have been linked to cancer development and therapeutic resistance, but the signaling mechanisms regulating CSC genes and phenotype are incompletely understood. CK2 has emerged as a key signal serine/threonine kinase that modulates diverse signal cascades regulating cell fate and growth. We previously showed that CK2 is often aberrantly expressed and activated in head and neck squamous cell carcinomas (HNSCC), concomitantly with mutant (mt) tumor suppressor TP53, and inactivation of its family member, TAp73. Unexpectedly, we observed that classical stem cell genes Nanog, Sox2, and Oct4, are overexpressed in HNSCC with inactivated TAp73 and mtTP53. However, the potential relationship between CK2, TAp73 inactivation, and CSC phenotype is unknown. We reveal that inhibition of CK2 by pharmacologic inhibitors or siRNA inhibits the expression of CSC genes and side population (SP), while enhancing TAp73 mRNA and protein expression. Conversely, CK2 inhibitor attenuation of CSC protein expression and the SP by was abrogated by TAp73 siRNA. Bioinformatic analysis uncovered a single predicted CK2 threonine phosphorylation site (T27) within the N-terminal transactivation domain of TAp73. Nuclear CK2 and TAp73 interaction, confirmed by co-immunoprecipitation, was attenuated by CK2 inhibitor, or a T27A point-mutation of this predicted CK2 threonine phospho-acceptor site of TAp73. Further, T27A mutation attenuated phosphorylation, while enhancing TAp73 function in repressing CSC gene expression and SP cells. A new CK2 inhibitor, CX-4945, inhibited CSC related SP cells, clonogenic survival, and spheroid formation. Our study unveils a novel regulatory mechanism whereby aberrant CK2 signaling inhibits TAp73 to promote the expression of CSC genes and phenotype.

Casein kinase: the triple meaning of a misnomer

The term 'casein kinase' has been widely used for decades to denote protein kinases sharing the ability to readily phosphorylate casein in vitro. These fall into three main classes: two of them, later renamed as protein kinases CK1 (casein kinase 1, also known as CKI) and CK2 (also known as CKII), are pleiotropic members of the kinome functionally unrelated to casein, whereas G-CK, or genuine casein kinase, responsible for the phosphorylation of casein in the Golgi apparatus of the lactating mammary gland, has only been identified recently with Fam20C [family with sequence similarity 20C; also known as DMP-4 (dentin matrix protein-4)], a member of the four-jointed family of atypical protein kinases, being responsible for the phosphorylation of many secreted proteins. In hindsight, therefore, the term 'casein kinase' is misleading in every instance; in the case of CK1 and CK2, it is because casein is not a physiological substrate, and in the case of G-CK/Fam20C/DMP-4, it is because casein is just one out of a plethora of its targets, and a rather marginal one at that. Strikingly, casein kinases altogether, albeit representing a minimal proportion of the whole kinome, appear to be responsible for the generation of up to 40-50% of non-redundant phosphosites currently retrieved in human phosphopeptides database. In the present review, a short historical explanation will be provided accounting for the usage of the same misnomer to denote three unrelated classes of protein kinases, together with an update of our current knowledge of these pleiotropic enzymes, sharing the same misnomer while playing very distinct biological roles.

Mechanism and efficacy of sub-50-nm tenfibgen nanocapsules for cancer cell-directed delivery of anti-CK2 RNAi to primary and metastatic squamous cell carcinoma

Improved survival for patients with head and neck cancers (HNC) with recurrent and metastatic disease warrants that cancer therapy is specific, with protected delivery of the therapeutic agent to primary and metastatic cancer cells. A further objective should be that downregulation of the intracellular therapy target leads to cell death without compensation by an alternate pathway. To address these goals, we report the utilization of a sub-50-nm tenfibgen (s50-TBG) nanocapsule that delivers RNAi oligonucleotides directed against the essential survival signal protein kinase CK2 (RNAi-CK2) in a cancer cell-specific manner. We have evaluated mechanism and efficacy of using s50-TBG-RNAi-CK2 nanocapsules for therapy of primary and metastatic head and neck squamous cell carcinoma (HNSCC). s50-TBG nanocapsules enter cancer cells via the lipid raft/caveolar pathway and deliver their cargo (RNAi-CK2) preferentially to malignant but not normal tissues in mice. Our data suggest that RNAi-CK2, a unique single-stranded oligonucleotide, co-opts the argonaute 2/RNA-induced silencing complex pathway to target the CK2αα' mRNAs. s50-TBG-RNAi-CK2 inhibited cell growth corresponding with reduced CK2 expression in targeted tumor cells. Treatment of three xenograft HNSCC models showed that primary tumors and metastases responded to s50-TBG-RNAi-CK2 therapy, with tumor shrinkage and 6-month host survival that was achieved at relatively low doses of the therapeutic agent without any adverse toxic effect in normal tissues in the mice. We suggest that our nanocapsule technology and anti-CK2 targeting combine into a therapeutic modality with a potential of significant translational promise.

Tenfibgen-DMAT Nanocapsule Delivers CK2 Inhibitor DMAT to Prostate Cancer Xenograft Tumors Causing Inhibition of Cell Proliferation

CK2 is a master regulator protein kinase which demonstrates heightened expression in diverse cancer types and is considered a promising target for therapy. Given its ubiquitous expression and potent influence on cell survival, cancer cell-directed targeting of the CK2 signal is an important factor for development of an anti-CK2 therapeutic. We previously reported on the malignant cell specificity and effect on CK2 signaling of a tenfibgen (TBG) based nanocapsule for delivery of the CK2 small molecule inhibitor 2-dimethylamino-4,5,6,7-tetrabromo-1H-benzimidazole (DMAT) in cultured prostate cancer cells. Here we tested the ability of TBG-DMAT to affect the growth of prostate xenograft tumors in mice. Our results show that treatment of PC3-LN4 xenograft tumors with TBG-DMAT caused loss of proliferative Ki-67 signal as well as Nuclear Factor-kappa B (NF-κB) expression in the tumors. Further, the TBG-DMAT nanocapsule was detected in tumors and not in liver or testis. In conclusion, TBG-based nanocapsule delivery of anti-CK2 small molecule drugs holds significant promise for treatment of prostate cancer.

Characterizing the convergence of protein kinase CK2 and caspase-3 reveals isoform-specific phosphorylation of caspase-3 by CK2α': implications for pathological roles of CK2 in promoting cancer cell survival

Protein kinase CK2 has emerged as a promising candidate for the treatment of a number of cancers. This enzyme is comprised of two catalytic subunits (CK2 and/or CK2α′) that form complexes with homodimers of regulatory CK2β subunits. While catalytic and regulatory CK2 subunits are generally expressed at similar levels to form tetrameric complexes, asymmetric expression of CK2 subunits has been associated with various forms of cancer and the enhanced survival of cancer cells. To elucidate mechanisms responsible for regulation of cancer cell survival by CK2, we recently employed computational and experimental strategies that revealed widespread overlap between sites for CK2 phosphorylation and caspase cleavage. Among candidates with overlapping CK2 and caspase cleavage sites was caspase-3 that is phosphorylated by CK2 to prevent its activation by upstream caspases. To elucidate the precise relationship between CK2 and caspase-3, we modulated expression of individual CK2 subunits and demonstrated that CK2α′ exhibits a striking preference for caspase-3 phosphorylation in cells as compared to CK2α and that CK2β exhibits the capacity to abolish caspase-3 phosphorylation. Since caspase-3 represents the first CK2 substrate selectively phosphorylated by CK2α′ in cells, our work highlights divergent functions of the different forms of CK2. Given the involvement of CK2 in a diverse series of biological events and its association with various cancers, this work has important implications for identifying pathological roles of distinct forms of CK2 that could instruct efforts to selectively target individual CK2 subunits for therapy.

miR-125b acts as a tumor suppressor in breast tumorigenesis via its novel direct targets ENPEP, CK2-α, CCNJ, and MEGF9

MicroRNAs (miRNAs) play important roles in diverse biological processes and are emerging as key regulators of tumorigenesis and tumor progression. To explore the dysregulation of miRNAs in breast cancer, a genome-wide expression profiling of 939 miRNAs was performed in 50 breast cancer patients. A total of 35 miRNAs were aberrantly expressed between breast cancer tissue and adjacent normal breast tissue and several novel miRNAs were identified as potential oncogenes or tumor suppressor miRNAs in breast tumorigenesis. miR-125b exhibited the largest decrease in expression. Enforced miR-125b expression in mammary cells decreased cell proliferation by inducing G2/M cell cycle arrest and reduced anchorage-independent cell growth of cells of mammary origin. miR-125b was found to perform its tumor suppressor function via the direct targeting of the 3’-UTRs of ENPEP, CK2-α, CCNJ, and MEGF9 mRNAs. Silencing these miR-125b targets mimicked the biological effects of miR-125b overexpression, confirming that they are modulated by miR-125b. Analysis of ENPEP, CK2-α, CCNJ, and MEGF9 protein expression in breast cancer patients revealed that they were overexpressed in 56%, 40–56%, 20%, and 32% of the tumors, respectively. The expression of ENPEP and CK2-α was inversely correlated with miR-125b expression in breast tumors, indicating the relevance of these potential oncogenic proteins in breast cancer patients. Our results support a prognostic role for CK2-α, whose expression may help clinicians predict breast tumor aggressiveness. In particular, our results show that restoration of miR-125b expression or knockdown of ENPEP, CK2-α, CCNJ, or MEGF9 may provide novel approaches for the treatment of breast cancer.

Unraveling regulatory programs for NF-kappaB, p53 and microRNAs in head and neck squamous cell carcinoma

In head and neck squamous cell carcinoma (HNSCC), mutations of p53 usually coexist with aberrant activation of NF-kappaB (NF-κB), other transcription factors and microRNAs, which promote tumor pathogenesis. However, how these factors and microRNAs interact to globally modulate gene expression and mediate oncogenesis is not fully understood. We devised a novel bioinformatics method to uncover interactive relationships between transcription factors or microRNAs and genes. This approach is based on matrix decomposition modeling under the joint constraints of sparseness and regulator-target connectivity, and able to integrate gene expression profiling and binding data of regulators. We employed this method to infer the gene regulatory networks in HNSCC. We found that the majority of the predicted p53 targets overlapped with those for NF-κB, suggesting that the two transcription factors exert a concerted modulation on regulatory programs in tumor cells. We further investigated the interrelationships of p53 and NF-κB with five additional transcription factors, AP1, CEBPB, EGR1, SP1 and STAT3, and microRNAs mir21 and mir34ac. The resulting gene networks indicate that interactions among NF-κB, p53, and the two miRNAs likely regulate progression of HNSCC. We experimentally validated our findings by determining expression of the predicted NF-κB and p53 target genes by siRNA knock down, and by examining p53 binding activity on promoters of predicted target genes in the tumor cell lines. Our results elucidating the cross-regulations among NF-κB, p53, and microRNAs provide insights into the complex regulatory mechanisms underlying HNSCC, and shows an efficient approach to inferring gene regulatory programs in biological complex systems.