ATX-101, a Peptide Targeting PCNA, Has Antitumor Efficacy Alone or in Combination with Radiotherapy in Murine Models of Human Glioblastoma

Cell proliferation requires the orchestrated actions of a myriad of proteins regulating DNA replication, DNA repair and damage tolerance, and cell cycle. Proliferating cell nuclear antigen (PCNA) is a master regulator which interacts with multiple proteins functioning in these processes, and this makes PCNA an attractive target in anticancer therapies. Here, we show that a cell-penetrating peptide containing the AlkB homolog 2 PCNA-interacting motif (APIM), ATX-101, has antitumor activity in a panel of human glioblastoma multiforme (GBM) cell lines and patient-derived glioma-initiating cells (GICs). Their sensitivity to ATX-101 was not related to cellular levels of PCNA, or p53, PTEN, or MGMT status. However, ATX-101 reduced Akt/mTOR and DNA-PKcs signaling, and a correlation between high Akt activation and sensitivity for ATX-101 was found. ATX-101 increased the levels of γH2AX, DNA fragmentation, and apoptosis when combined with radiotherapy (RT). In line with the in vitro results, ATX-101 strongly reduced tumor growth in two subcutaneous xenografts and two orthotopic GBM models, both as a single agent and in combination with RT. The ability of ATX-101 to sensitize cells to RT is promising for further development of this compound for use in GBM.

Bisdemethoxycurcumin Induces Cell Apoptosis and Inhibits Human Brain Glioblastoma GBM 8401/Luc2 Cell Xenograft Tumor in Subcutaneous Nude Mice In Vivo

Bisdemethoxycurcumin (BDMC) has biological activities, including anticancer effects in vitro; however, its anticancer effects in human glioblastoma (GBM) cells have not been examined yet. This study aimed to evaluate the tumor inhibitory effect and molecular mechanism of BDMC on human GBM 8401/luc2 cells in vitro and in vivo. In vitro studies have shown that BDMC significantly reduced cell viability and induced cell apoptosis in GBM 8401/luc2 cells. Furthermore, BDMC induced apoptosis via inhibited Bcl-2 (anti-apoptotic protein) and increased Bax (pro-apoptotic proteins) and cytochrome c release in GBM 8401/luc2 cells in vitro. Then, twelve BALB/c-nude mice were xenografted with human glioblastoma GBM 8401/luc2 cancer cells subcutaneously, and the xenograft nude mice were treated without and with BDMC (30 and 60 mg/kg of BDMC treatment) every 3 days. GBM 8401/luc2 cell xenografts experiment showed that the growth of the tumors was significantly suppressed by BDMC administration at both doses based on the reduction of tumor size and weights. BDMC did not change the body weight and the H&E histopathology analysis of liver samples, indicating that BDMC did not induce systemic toxicity. Meanwhile, treatment with BDMC up-regulated the expressions of BAX and cleaved caspase-3, while it down-regulated the protein expressions of Bcl-2 and XIAP in the tumor tissues compared with the control group. This study has demonstrated that BDMC presents potent anticancer activity on the human glioblastoma GBM 8401/luc2 cell xenograft model by inducing apoptosis and inhibiting tumor cell proliferation and shows the potential for further development to the anti-GBM cancer drug.

Perphenazine and Prochlorperazine Decrease Glioblastoma U87-MG Cells Migration and Invasion: Analysis of the ABCB1 and ABCG2 Transporters, E-Cadherin, α-Tubulin, and Integrins (α3, α5, and β1) Levels.

Purpose: Glioblastoma multiforme is the most frequent malignant brain tumor as well as one of the most lethal and untreatable human tumors with a very poor survival rate. Thus, novel and effective strategies of treatment are required. Integrins play a crucial role in the regulation of cellular adhesion and invasion. Moreover, integrins and alpha-tubulin are very important in cell migration, while E-cadherin plays the main role in tumor metastasis. Their ability to penetrate the BBB and signs of intracerebral activity are very important in glioblastoma therapy. ABC transporters ABCB1 and ABCG2, which are localized in the brain endothelial capillaries of BBB, play a crucial role in the development of multidrug resistance, and are modulated by phenothiazine derivatives. Methods: The impact on the motility of human glioblastoma U87-MG was evaluated with a wound healing assay; cellular migration, and invasion by the transwell assay, while ABCB1, ABCG2, E-cadherin, α-tubulin, and integrins content was determined with the Western blot.Results: This study explores the effect of perphenazine and prochlorperazine on ABCB1, ABCG2, E-cadherin, α-tubulin, and integrins (α3, α5, and β1) amount as well as on migration and invasion ability of human glioblastoma (U87-MG) cells. The results suggest that perphenazine and prochlorperazine modulate multidrug resistance proteins (they decrease ABCB1 and increase ABCG2), E-cadherin, α-tubulin, and integrins amount as well as impair migration and invasion of the U87-MG cell line. Conclusions: The decrease of migration and invasion ability after phenothiazine derivatives treatment due to the increase of ABCG2 and E-cadherin as well as the decrease of α-tubulin, and integrins amounts can support the hypothesis that perphenazine and prochlorperazine have the anticancer effect on human glioblastoma U87-MG cells.

A System Bioinformatics Approach Predicts the Molecular Mechanism Underlying the Course of Action of Radix Salviae Reverses GBM Effects

Objective. This study used in vitro techniques to investigate the therapeutic effect of Radix Salviae on human glioblastoma and decode its underlying molecular mechanism. Methods. The active components and targets of the Radix Salviae were identified from the Traditional Chinese Medicine Systems Pharmacology Database (TCMSP). The targets of human glioblastoma were obtained from the GeneCards Database. The Radix Salviae-mediated antiglioblastoma was evaluated by Gene Ontology (GO) analyses and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses. Finally, mechanism of action of Radix Salviae against human glioblastoma was deduced by molecular docking and experiments. Results. We screened 66 active ingredients and 45 targets of the Radix Salviae. The enrichment analysis based on the targets mentioned above suggested a possible role in protein phosphorylation, cell transcription, apoptosis, and inflammatory factor signaling pathways. Further study demonstrated that cryptotanshinone, an essential component of Radix Salviae, played a significant role in killing human glioblastoma cells and protecting the body by inhibiting the AKT, IKB, and STAT3 signaling pathways. Conclusions. Radix Salviae could inhibit the proliferation and invasion of human glioblastoma by regulating STAT3, Akt, and IKB signaling pathways. Radix Salviae has potential therapeutic value in the future for human glioblastoma.

Intercomparison of Radiosensitization Induced by Gold and Iron Oxide Nanoparticles in Human Glioblastoma Cells Irradiated by 6 MV Photons

In this work, an intercomparison of sensitization effects produced by gold (GNP) and dextran-coated iron oxide (SPION-DX) nanoparticles in M059J and U87 human glioblastoma cells was performed using 6MV-photons. Three variables were mapped: the nanoparticle material, treatment concentration, and cell radiosensitivity. For U87, GNP treatments resulted in high sensitization enhancement ratios (SER10% up to 2.04). More modest effects were induced by SPION-DX, but still significant reductions in survival were achieved (maximum SER10%=1.61). For the radiosensitive M059J, sensitization by both NPs was poor. SER10% increased with the degree of elemental uptake in the cells, but not necessarily with treatment concentration. For GNP, where exposure concentration and elemental uptake were found to be proportional, SER10% increased linearly with concentration in both cell lines. For SPION-DX, saturation of sensitization enhancement and metal uptake occurred at high exposures. Fold change in the α/β ratios extracted from survival curves are reduced by the presence of SPION-DX but strongly increased by GNPs, suggesting that sensitization by GNPs occurs mainly via promotion of lethal damage, while for SPION-DX repairable damage dominates. The NPs were more effective in eliminating the radioresistant glioblastoma cells, an interesting finding, as resistant cells are key targets to improve treatment outcome.

Differential proliferative and cytotoxic effect of selected components of essential oils on human glioblastoma cells

Background: In the study of bioactive agents from traditional medicine, mono- and sesquiterpenes represent the main ingredients of essential oils. Till now, only thymoquinone and perillyl alcohol have been clinically tested on glioblastoma. Objective: In the present study, we examined the effect of ten different essential oils on three human glioblastoma cell lines and one healthy human cell line. Methods: We used confocal laser scanning microscopy, flow cytometry, and cell growth analysis to evaluate cell morphology changes, membrane disruption effects, acute cytotoxicity and effects on the proliferation rate caused by the essential oils pinene, geraniol, eucalyptol, perillaldehyde, limonene, and linalool, perillyl alcohol, myrcene, bisabolol and valencene on human cells. Caspase 3/7 activity was measured to observe apoptosis induced by the essential oils. Results: We found that the cytotoxicity concentrations varied not only between different essential oils but also among different cell lines. Acute cytotoxicity of essential oils was based on cell membrane disruption and that HEK cells were affected to a much higher degree than the Glioblastoma cells. Vacuoles found in surviving glioblastoma cells appeared to be a factor in this effect. Conclusion: Caspase activity did not correlate with the membrane damage observed in the flow cytometry experiments. This is especially evident in the HEK cells that only showed apoptosis with two out of ten essential oils.

Rutaecarpine Inhibits U87 Glioblastoma Cell Migration by Activating the Aryl Hydrocarbon Receptor Signaling Pathway

Glioblastoma is the most frequent and aggressive primary astrocytoma in adults. The high migration ability of the tumor cells is an important reason for the high recurrence rate and poor prognosis of glioblastoma. Recently, emerging evidence has shown that the migration ability of glioblastoma cells was inhibited upon the activation of aryl hydrocarbon receptor (AhR), suggesting potential anti-tumor effects of AhR agonists. Rutaecarpine is a natural compound with potential tumor therapeutic effects which can possibly bind to AhR. However, its effect on the migration of glioblastoma is unclear. Therefore, we aim to explore the effects of rutaecarpine on the migration of human glioblastoma cells U87 and the involvement of the AhR signaling pathway. The results showed that: (i) compared with other structural related alkaloids, like evodiamine and dehydroevodiamine, rutaecarpine was a more potent AhR activator, and has a stronger inhibitory effect on the glioblastoma cell migration; (ii) rutaecarpine decreased the migration ability of U87 cells in an AhR-dependent manner; (iii) AhR mediated the expression of a tumor suppressor interleukin 24 (IL24) induced by rutaecarpine, and AhR-IL24 axis was involved in the anti-migratory effects of rutaecarpine on the glioblastoma. Besides IL24, other candidates AhR downstream genes both associated with cancer and migration were proposed to participate in the migration regulation of rutaecarpine by RNA-Seq and bioinformatic analysis. These data indicate that rutaecarpine is a naturally-derived AhR agonist that could inhibit the migration of U87 human glioblastoma cells mostly via the AhR-IL24 axis.