Effect of duty cycles of tumor‑treating fields on glioblastoma cells and normal brain organoids

Abstract Background Glioblastoma multiforme, the most aggressive and malignant primary brain tumor, is characterized by rapid growth and extensive infiltration to neighboring normal brain parenchyma. Our previous studies delineated a crosstalk between PI3K/Akt and JNK signaling pathways, and a moderate anti-glioblastoma synergism caused by the combined inhibition of PI3K p110β (PI3Kβ) isoform and JNK. However, this combination strategy is not potent enough. MLK3, an upstream regulator of ERK and JNK, may replace JNK to exert stronger synergism with PI3Kβ. Methods To develop a new combination strategy with stronger synergism, the expression pattern and roles of MLK3 in glioblastoma patient’s specimens and cell lines were firstly investigated. Then glioblastoma cells and xenografts in nude mice were treated with the PI3Kβ inhibitor AZD6482 and the MLK3 inhibitor URMC-099 alone or in combination to evaluate their combination effects on tumor cell growth and motility. The combination effects on cytoskeletal structures such as lamellipodia and focal adhesions were also evaluated. Results MLK3 protein was overexpressed in both newly diagnosed and relapsing glioblastoma patients’ specimens. Silencing of MLK3 using siRNA duplexes significantly suppressed migration and invasion, but promoted attachment of glioblastoma cells. Combined inhibition of PI3Kβ and MLK3 exhibited synergistic inhibitory effects on glioblastoma cell proliferation, migration and invasion, as well as the formation of lamellipodia and focal adhesions. Furthermore, combination of AZD6482 and URMC-099 effectively decreased glioblastoma xenograft growth in nude mice. Glioblastoma cells treated with this drug combination showed reduced phosphorylation of Akt and ERK, and decreased protein expression of ROCK2 and Zyxin. Conclusion Taken together, combination of AZD6482 and URMC-099 showed strong synergistic anti-tumor effects on glioblastoma in vitro and in vivo. Our findings suggest that combined inhibition of PI3Kβ and MLK3 may serve as an attractive therapeutic approach for glioblastoma multiforme.

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NOX4-derived ROS-induced overexpression of FOXM1 regulates aerobic glycolysis in glioblastoma

BMC Cancer ◽

10.1186/s12885-021-08933-y ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Xiangsheng Su ◽

Yihang Yang ◽

Qing Yang ◽

Bo Pang ◽

Shicheng Sun ◽

...

Keyword(s):

Reactive Oxygen Species ◽

Western Blot ◽

Aerobic Glycolysis ◽

Reactive Oxygen ◽

Normal Brain ◽

Oxygen Species ◽

Glioblastoma Cells ◽

Foxm1 Expression ◽

Brain Tissues

Abstract Background Increased expression of the transcription factor Forkhead box M1 (FOXM1) has been reported to play an important role in the progression and development of multiple tumors, but the molecular mechanisms that regulate FOXM1 expression remain unknown, and the role of FOXM1 in aerobic glycolysis is still not clear. Methods The expression of FOXM1 and NADPH oxidase 4 (NOX4) in normal brain tissues and glioma was detected in data from the TCGA database and in our specimens. The effect of NOX4 on the expression of FOXM1 was determined by Western blot, qPCR, reactive oxygen species (ROS) production assays, and luciferase assays. The functions of NOX4 and FOXM1 in aerobic glycolysis in glioblastoma cells were determined by a series of experiments, such as Western blot, extracellular acidification rate (ECAR), lactate production, and intracellular ATP level assays. A xenograft mouse model was established to test our findings in vivo. Results The expression of FOXM1 and NOX4 was increased in glioma specimens compared with normal brain tissues and correlated with poor clinical outcomes. Aberrant mitochondrial reactive oxygen species (ROS) generation of NOX4 induced FOXM1 expression. Mechanistic studies demonstrated that NOX4-derived MitoROS exert their regulatory role on FOXM1 by mediating hypoxia-inducible factor 1α (HIF-1α) stabilization. Further research showed that NOX4-derived MitoROS-induced HIF-1α directly activates the transcription of FOXM1 and results in increased FOXM1 expression. Overexpression of NOX4 or FOXM1 promoted aerobic glycolysis, whereas knockdown of NOX4 or FOXM1 significantly suppressed aerobic glycolysis, in glioblastoma cells. NOX4-induced aerobic glycolysis was dependent on elevated FOXM1 expression, as FOXM1 knockdown abolished NOX4-induced aerobic glycolysis in glioblastoma cells both in vitro and in vivo. Conclusion Increased expression of FOXM1 induced by NOX4-derived MitoROS plays a pivotal role in aerobic glycolysis, and our findings suggest that inhibition of NOX4-FOXM1 signaling may present a potential therapeutic target for glioblastoma treatment.

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MCP-1 and MIP-3α Secreted from Necrotic Cell-Treated Glioblastoma Cells Promote Migration/Infiltration of Microglia

Cellular Physiology and Biochemistry ◽

10.1159/000492092 ◽

2018 ◽

Vol 48 (3) ◽

pp. 1332-1346 ◽

Cited By ~ 5

Author(s):

Yieun Jung ◽

So-Hee Ahn ◽

Hyunju Park ◽

Sang Hui Park ◽

Kyungsun Choi ◽

...

Keyword(s):

Protein Expression ◽

Primary Brain Tumor ◽

Brain Parenchyma ◽

Migration And Invasion ◽

Normal Brain ◽

Glioblastoma Cells ◽

Mobility Shift ◽

Diffuse Infiltration ◽

Nuclear Extracts ◽

Mrna And Protein Expression

Background/Aims: Glioblastoma multiforme (GBM) is the most common primary brain tumor in adults. The defining characteristics of GBM are diffuse infiltration of tumor cells into normal brain parenchyma, rapid growth, a high degree of infiltration of microglia and macrophages, and the presence of necrosis. Microglia/macrophages are frequently found in gliomas and they extensively infiltrate GBM tissue, up to 30% of total tumor mass. However, little is known about the effect of necrotic cells (NCs) on microglia infiltration in GBM and the tumor-infiltrating microglia-induced factors in GBMs. Methods: In this study, to address whether necrosis or necrosis-exposed GBM cells affect the degree of microglia/macrophage infiltration, migration and invasion/infiltration assays were performed. Culture supernatants and nuclear extracts of CRT-MG cells treated or untreated with necrotic cells were analyzed using a chemokine array and electrophoretic mobility shift assay, respectively. Results: The presence of NCs promoted the migration/infiltration of microglia, and GBM cell line CRT-MG cells exposed to NCs further enhanced the migration and infiltration of HMO6 microglial cells. Treatment with NCs induced mRNA and protein expression of chemokines such as <unterline>M</unterline>onocyte <unterline>C</unterline>hemoattractant <unterline>P</unterline>rotein-1 (CCL2/MCP-1) and <unterline>M</unterline>acrophage <unterline>I</unterline>nflammatory <unterline>P</unterline>rotein-3α (CCL20/MIP-3α) in CRT-MG cells. In particular, CCL2/MCP-1 and CCL20/MIP-3α were significantly increased in NC-treated CRT-MG cells. NCs induced DNA binding of the transcription factors <unterline>N</unterline>uclear <unterline>F</unterline>actor (NF)-κB and <unterline>A</unterline>ctivator <unterline>P</unterline>rotein 1 (AP-1) to the CCL2/MCP-1 and CCL20/MIP-3α promoters, leading to increased CCL2/MCP-1 and CCL20/MIP-3α mRNA and protein expression in CRT-MG cells. Conclusion: These results provide evidence that NCs induce the expression of CCL2/MCP-1 and CCL20/MIP-3α in glioblastoma cells through activation of NF-κB and AP-1 and facilitate the infiltration of microglia into tumor tissues.

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Abstract 1860: Tumor-treating fields (TTFields) effects on glioblastoma cells are augmented by mitotic checkpoint inhibition

10.1158/1538-7445.am2018-1860 ◽

2018 ◽

Cited By ~ 1

Author(s):

Almuth F. Kessler ◽

Greta E. Frömbling ◽

Franziska Gross ◽

Mirja Hahn ◽

Wilfrid Dzokou ◽

...

Keyword(s):

Mitotic Checkpoint ◽

Checkpoint Inhibition ◽

Glioblastoma Cells ◽

Tumor Treating Fields

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