cx-4945 and Glioblastoma

The relevance of the cancer immune cycle in therapy response implies that successful treatment may trigger the exposure or the release of immunogenic signals. Previous results with the preclinical GL261 glioblastoma (GB) showed that combination treatment of temozolomide (TMZ) + CX-4945 (protein kinase CK2 inhibitor) outperformed single treatments, provided an immune-friendly schedule was followed. Our purpose was to study possible immunogenic signals released in vitro by GB cells.. GL261 GB cells were treated with TMZ and CX-4945 at different concentrations (25 µM-4 mM) and time frames (12-72 h). Cell viability was measured with Trypan Blue and propidium iodide. Calreticulin exposure was assessed with immunofluorescence, and ATP release was measured with bioluminescence.. TMZ showed cytostatic rather than cytotoxic effects, while CX-4945 showed remarkable cytotoxic effects already at low concentrations. Calreticulin exposure after 24 h was detected with TMZ treatment, as well as TMZ/CX-4945 low concentration combined treatment. ATP release was significantly higher with CX-4945, especially at high concentrations, as well as with TMZ/CX-4945.. combined treatment may produce the simultaneous release of two potent immunogenic signals, which can explain the outperformance over single treatments in vivo. A word of caution may be raised since in vitro conditions are not able to mimic pharmacokinetics observed in vivo fully.

Topics: Adenosine Triphosphate; Antineoplastic Agents, Alkylating; Antineoplastic Combined Chemotherapy Protocols; Brain Neoplasms; Calreticulin; Casein Kinase II; Cell Line, Tumor; Cell Survival; Combined Modality Therapy; Glioblastoma; Humans; Inflammation; Microscopy, Fluorescence; Naphthyridines; Phenazines; Propidium; Signal Transduction; Temozolomide; Treatment Outcome

Protein kinase CK2 is a ubiquitously expressed serine/threonine kinase composed of two catalytic subunits (α) and/or (α') and two regulatory (β) subunits. The expression and kinase activity of CK2 is elevated in many different cancers, including glioblastoma (GBM). Brain tumor initiating cells (BTICs) are a subset of cells that are highly tumorigenic and promote the resistance of GBM to current therapies. We previously reported that CK2 activity promotes prosurvival signaling in GBM. In this study, the role of CK2 signaling in BTIC function was examined. We found that expression of CK2α was increased in CD133

Topics: AC133 Antigen; Animals; Brain Neoplasms; Casein Kinase II; Cell Line, Tumor; Cell Proliferation; Embryo, Mammalian; Enzyme Inhibitors; Female; Gefitinib; Glioblastoma; Humans; Mice; Mice, Inbred C57BL; Mice, Nude; Naphthyridines; Neoplastic Stem Cells; Phenazines; Pregnancy; Quinazolines; RNA, Small Interfering; Signal Transduction; Xenograft Model Antitumor Assays

Casein kinase II contributes to the growth and survival of malignant gliomas and attracts increasing attention as a therapeutic target in these tumors. Several reports have suggested that this strategy might be most relevant for specific subgroups of patients, namely Verhaak's classical and TP53 wild-type tumors. Using kinase assays and microarray genetic profiling in a series of 27 proprietary fresh frozen surgical glioma samples, we showed that constitutive CK2 kinase activation is not restricted to tumors that present increased copy numbers or mRNA expression of its catalytic or regulatory subunits, and can result from a functional activation by various cytokines from the glioma microenvironment. Using corresponding primary tumor and human astrocyte cell cultures as well as glioma cell lines, we confirmed that CK2 inhibition is selectively toxic to malignant glial tumors, without any restriction to tumor class or to TP53 status. We finally showed that while the contribution of CK2 to the constitutive NF-κB hyperactivation in malignant gliomas is at best moderate, a delayed activation of NF-κB may associate with the therapeutic resistance of glioma cells to CK2 inhibition.

Topics: Apigenin; Brain Neoplasms; Casein Kinase II; Cell Line, Tumor; Cell Proliferation; Cell Survival; Enzyme Activation; Gene Expression Profiling; Gene Expression Regulation, Neoplastic; Glioblastoma; Humans; Naphthyridines; Phenazines; Tissue Array Analysis; Tumor Microenvironment; Tumor Suppressor Protein p53

Glioblastoma (GBM) is the most common and fatal primary brain tumor in humans, and it is essential that new and better therapies are developed to treat this disease. Previous research suggests that casein kinase 2 (CK2) may be a promising therapeutic target for GBMs. CK2 has enhanced expression or activity in numerous cancers, including GBM, and it has been demonstrated that inhibitors of CK2 regressed tumor growth in GBM xenograft mouse models. Our studies demonstrate that the CK2 subunit, CK2α, is overexpressed in and has an important role in regulating brain tumor-initiating cells (BTIC) in GBM. Initial studies showed that two GBM cell lines (U87-MG and U138) transduced with CK2α had enhanced proliferation and anchorage-independent growth. Inhibition of CKα using siRNA or small-molecule inhibitors (TBBz, CX-4945) reduced cell growth, decreased tumor size, and increased survival rates in GBM xenograft mouse models. We also verified that inhibition of CK2α decreased the activity of a well-known GBM-initiating cell regulator, β-catenin. Loss of CK2α decreased two β-catenin-regulated genes that are involved in GBM-initiating cell growth, OCT4 and NANOG. To determine the importance of CK2α in GBM stem cell maintenance, we reduced CK2α activity in primary GBM samples and tumor spheres derived from GBM patients. We discovered that loss of CK2α activity reduced the sphere-forming capacity of BTIC and decreased numerous GBM stem cell markers, including CD133, CD90, CD49f and A2B5. Our study suggests that CK2α is involved in GBM tumorigenesis by maintaining BTIC through the regulation of β-catenin.

Topics: Animals; Benzimidazoles; beta Catenin; Brain Neoplasms; Casein Kinase II; Cell Line, Tumor; Cell Proliferation; Glioblastoma; Humans; Mice; Naphthyridines; Neoplasm Transplantation; Neoplastic Stem Cells; Phenazines; Prognosis; Signal Transduction; Survival Analysis

Gliomas are the most frequently occurring primary malignancies in the brain, and glioblastoma is the most aggressive of these tumors. Protein kinase CK2 is composed of two catalytic subunits (α and/or α') and two β regulatory subunits. CK2 suppresses apoptosis, promotes neoangiogenesis, and enhances activation of the JAK/STAT, NF-κB, PI3K/AKT, Hsp90, Wnt, and Hedgehog pathways. Aberrant activation of the NF-κB, PI3K/AKT, and JAK/STAT-3 pathways is implicated in glioblastoma progression. As CK2 is involved in their activation, the expression and function of CK2 in glioblastoma was evaluated.. Analysis of 537 glioblastomas from The Cancer Genome Atlas Project demonstrates the CSNK2A1 gene, encoding CK2α, has gene dosage gains in glioblastoma (33.7%), and is significantly associated with the classical glioblastoma subtype. Inhibition of CK2 activity by CX-4945, a selective CK2 inhibitor, or CK2 knockdown by siRNA suppresses activation of the JAK/STAT, NF-κB, and AKT pathways and downstream gene expression in human glioblastoma xenografts. On a functional level, CX-4945 treatment decreases the adhesion and migration of glioblastoma cells, in part through inhibition of integrin β1 and α4 expression. In vivo, CX-4945 inhibits activation of STAT-3, NF-κB p65, and AKT, and promotes survival of mice with intracranial human glioblastoma xenografts.. CK2 inhibitors may be considered for treatment of patients with glioblastoma.

Topics: Animals; Antineoplastic Agents; Brain Neoplasms; Casein Kinase II; Cell Adhesion; Cell Line, Tumor; Cell Movement; Cell Proliferation; Cell Survival; Enzyme Activation; Female; Gene Amplification; Gene Dosage; Glioblastoma; Humans; Mice; Mice, Nude; Naphthyridines; Phenazines; Proto-Oncogene Proteins c-akt; Signal Transduction; STAT3 Transcription Factor; Xenograft Model Antitumor Assays

Glioblastoma is the most prevalent and malignant primary brain tumor in adults, and its response to current therapies is limited. Protein kinase CK2 is overexpressed in glioblastoma and regulates glioblastoma cell survival, proliferation, and migration and brain tumorigenesis. Targeting CK2 for glioblastoma treatment may benefit patients with glioblastoma.

Topics: Animals; Antineoplastic Agents; Brain Neoplasms; Casein Kinase II; Female; Glioblastoma; Humans; Naphthyridines; Phenazines; Signal Transduction