Background: Temozolomide (TMZ) is a first-line chemotherapeutic drug for malignant gliomas. Nonetheless, TMZ-induced side effects and drug resistance remain challenges. Our previous study showed the suppressive effects of honokiol on growth of gliomas.
Purpose: This study was further aimed to evaluate if honokiol could enhance TMZ-induced insults toward malignant glioma cells and its possible mechanisms.
Methods: Human U87 MG glioma cells were exposed to TMZ, honokiol, and a combination of TMZ and honokiol. Cell survival, apoptosis, necrosis, and proliferation were successively assayed. Fluorometric substrate assays were conducted to determine activities of caspase-3, -6, -8, and -9. Levels of Fas ligand, Bax, and cytochrome c were immunodetected. Translocation of Bax to mitochondria were examined using confocal microscopy. Mitochondrial function was evaluated by assaying the mitochondrial membrane potential (MMP), reactive oxygen species (ROS), and complex I enzyme activity. Caspase-6 activity was suppressed using specific peptide inhibitors. The honokiol-induced effects were further confirmed using human U373 MG and murine GL261 cells.
Results: Exposure of human U87 MG glioma cells to honokiol significantly increased TMZ-induced DNA fragmentation and cell apoptosis. Interestingly, honokiol enhanced intrinsic caspase-9 activity without affecting extrinsic Fas ligand levels and caspase-8 activity. Sequentially, TMZ-induced changes in Bax translocation, the MMP, mitochondrial complex I enzyme activity, intracellular ROS levels, and cytochrome c release were enhanced by honokiol. Consequently, honokiol amplified TMZ-induced activation of caspases-3 and -6 in human U87 MG cells. Fascinatingly, suppressing caspase-6 activity concurrently decreased honokiol-induced DNA fragmentation and cell apoptosis. The honokiol-involved improvement in TMZ-induced intrinsic apoptosis was also confirmed in human U373 MG and murine GL261 glioma cells.
Conclusions: This study showed that honokiol can enhance TMZ-induced apoptotic insults to glioma cells via an intrinsic mitochondrion-dependent mechanism. Our results suggest the therapeutic potential of honokiol to attenuate TMZ-induced side effects.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1016/j.phymed.2018.06.012 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Distinct roles of small extracellular vesicles from resident and infiltrating macrophages on glioma growth and mobility.
J Cancer
January 2025
Department of Medical Imaging and Radiological Sciences, Chang Gung University, Taoyuan, 33302, Taiwan.
Previous studies revealed that tumor-associated macrophages/microglia (TAMs) promoted glioma invasiveness during tumor progression and after radiotherapy. However, the communication of TAMs with tumor cells remains unclear. This study aimed to examine the role of small extracellular vesicles (sEVs) derived from TAMs in TAMs-mediated brain tumor invasion.
View Article and Find Full Text PDFRelationship between CTF1 gene expression and prognosis and tumor immune microenvironment in glioma.
Eur J Med Res
January 2025
Department of Neurosurgery, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, No 17 Panjiayuan Nanli, Chaoyang District, Beijing, 100021, People's Republic of China.
Objective: This study aimed to evaluate CTF1 expression in glioma, its relationship to patient prognosis and the tumor immune microenvironment, and effects on glioma phenotypes to identify a new therapeutic target for treating glioma precisely.
Methods: We initially assessed the expression of CTF1, a member of the IL-6 family, in glioma, using bioinformatics tools and publicly available databases. Furthermore, we examined the correlation between CTF1 expression and tumor prognosis, DNA methylation patterns, m6A-related genes, potential biological functions, the immune microenvironment, and genes associated with immune checkpoints.
Biopsy location and tumor-associated macrophages in predicting malignant glioma recurrence using an in-silico model.
NPJ Syst Biol Appl
January 2025
Center for Interdisciplinary Digital Sciences (CIDS), Department Information Services and High-Performance Computing (ZIH), Dresden University of Technology, 01062, Dresden, Germany.
Predicting the biological behavior and time to recurrence (TTR) of high-grade diffuse gliomas (HGG) after maximum safe neurosurgical resection and combined radiation and chemotherapy plays a pivotal role in planning clinical follow-up, selecting potentially necessary second-line treatment and improving the quality of life for patients diagnosed with a malignant brain tumor. The current standard-of-care (SoC) for HGG includes follow-up neuroradiological imaging to detect recurrence as early as possible and relies on several clinical, neuropathological, and radiological prognostic factors, which have limited accuracy in predicting TTR. In this study, using an in-silico analysis, we aim to improve predictive power for TTR by considering the role of (i) prognostically relevant information available through diagnostics used in the current SoC, (ii) advanced image-based information not currently part of the standard diagnostic workup, such as tumor-normal tissue interface (edge) features and quantitative data specific to biopsy positions within the tumor, and (iii) information on tumor-associated macrophages.
View Article and Find Full Text PDFCholine kinase alpha regulates autophagy-associated exosome release to promote glioma cell progression.
Biochem Biophys Res Commun
December 2024
Department of Neurosurgery, General Hospital of Ningxia Medical University, Yinchuan, China. Electronic address:
Glioma is the most common primary intracranial malignant tumor in adults, with a poor prognosis. Exosomes released by tumor cells play a crucial role in tumor development, metastasis, angiogenesis, and other biological processes. Despite this significance, the precise molecular mechanisms governing exosome secretion and their impact on tumor progression remain incompletely understood.
View Article and Find Full Text PDFA specific and adaptable approach to track CD206 macrophages by molecular MRI and fluorescence imaging.
Theranostics
January 2025
Institute for Innovation in Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, Massachusetts, 02129, MA.
The mannose receptor (CD206, expressed by the gene ) is a surface marker overexpressed by anti-inflammatory and pro-tumoral macrophages. As such, CD206 macrophages play key roles in the immune response to different pathophysiological conditions and represent a promising diagnostic and therapeutic target. However, methods to specifically target these cells remain challenging.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!