acteoside and Glioblastoma

Glioblastoma (GBM) continues to show a poor prognosis despite advances in diagnostic and therapeutic approaches. The discovery of reliable prognostic indicators may significantly improve treatment outcome of GBM. In this study, we aimed to explore the function of verbascoside (VB) in GBM and its effects on GBM cell biological processes via let-7g-5p and HMGA2. Differentially expressed GBM-related microRNAs (miRNAs) were initially screened. Different concentrations of VB were applied to U87 and U251 GBM cells, and 50 µmol/L of VB was selected for subsequent experiments. Cells were transfected with let-7g-5p inhibitor or mimic, and overexpression of HMGA2 or siRNA against HMGA2 was induced, followed by treatment with VB. The regulatory relationships between VB, let-7g-5p, HMGA2 and Wnt/β-catenin signalling pathway were determined. The results showed that HMGA2 was a direct target gene of let-7g-5p. VB treatment or let-7g-5p overexpression inhibited HMGA2 expression and the activation of Wnt/β-catenin signalling pathway, which further inhibited cell viability, invasion, migration, tumour growth and promoted GBM cell apoptosis and autophagy. On the contrary, HMGA2 overexpression promoted cell viability, invasion, migration, tumour growth while inhibiting GBM cell apoptosis and autophagy. We demonstrated that VB inhibits cell viability and promotes cell autophagy in GBM cells by up-regulating let-7g-5p and down-regulating HMGA2 via Wnt/β-catenin signalling blockade.

Topics: Animals; Apoptosis; Autophagy; Base Sequence; Brain Neoplasms; Cell Line, Tumor; Cell Movement; Cell Survival; Disease Progression; Down-Regulation; Gene Expression Regulation, Neoplastic; Glioblastoma; Glucosides; HMGA2 Protein; Humans; Mice, Nude; MicroRNAs; Neoplasm Invasiveness; Phenols; Protein Kinase C; Wnt Signaling Pathway; Xenograft Model Antitumor Assays

Temozolomide (TMZ) is an alkylating agent commonly used as a first‑line treatment for high‑grade glioblastoma. However, TMZ has short half‑life and frequently induces tumor resistance, which can limit its therapeutic efficiency. In the present study, it was hypothesized that combined treatment with TMZ and acteoside has synergistic effects in glioblastoma therapy. Using cell viability and wound‑healing assays, it was determined that this treatment regimen reduced cell viability and migration to a greater extent than either TMZ or acteoside alone. Following previous reports that TMZ affected autophagy in glioma cells, the present study examined the effects of TMZ + acteoside combination treatment on apoptosis and autophagy. The TMZ + acteoside combination treatment increased the cleavage of caspase‑3 and levels of B‑cell lymphoma 2 (Bcl‑2)‑associated X protein and phosphorylated p53, and decreased the level of Bcl‑2. The combination treatment increased microtubule‑associated protein 1 light chain 3 and apoptosis‑related gene expression. It was also determined that TMZ + acteoside induced apoptosis and autophagy through the mitogen‑activated protein kinase signaling pathway. These findings suggest that acteoside has beneficial effects on TMZ‑based glioblastoma therapy.

Topics: Animals; Antineoplastic Agents, Alkylating; Antineoplastic Agents, Phytogenic; Apoptosis; Autophagy; Cell Line, Tumor; Cell Proliferation; Cell Survival; Drug Synergism; Gene Expression Regulation, Neoplastic; Glioblastoma; Glucosides; MAP Kinase Signaling System; Phenols; Rats; Temozolomide

Verbascoside (VB), a glycosylated phenylpropanoid compound, is derived from the plant Syringa vulgaris (Oleaceae) and has been shown to have antitumor effects in multiple human cancers, including glioblastoma (GBM); however, the underlying mechanism has not been completely elucidated. Epithelial-to-mesenchymal transition (EMT) is the pivotal event in tumor progression. c-Met, a receptor tyrosine kinase, plays an important role in GBM aggressiveness via promoting EMT. The current study aimed to explore whether VB suppresses c-Met-induced EMT and investigated the mechanism of c-Met degradation. We found that VB inhibited GBM cell growth and downregulated c-Met and the EMT markers (snail, vimentin, and zeb1) in vitro and in an orthotopic xenograft mouse model. In addition, overexpressing c-Met in glioblastoma cells abolished the effects of VB on EMT. We also used a microscale thermophoresis (MST) assay to show that VB could directly bind to the c-Met protein, and we showed that VB degraded the c-Met protein via the ubiquitination-proteasome pathway. Our study is the first to identify a new mechanism for the anticancer effects of VB, namely, the inhibition of EMT by directly targeting c-Met; the inhibition of EMT results in c-Met protein degradation through the ubiquitination-proteasome pathway. Our current research indicates that VB is a potential agent to treat GBM via the ubiquitin-mediated degradation of c-Met.

Topics: Antineoplastic Agents, Phytogenic; Cell Movement; Cell Proliferation; Cell Survival; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; Epithelial-Mesenchymal Transition; Glioblastoma; Glucosides; Humans; Phenols; Proto-Oncogene Proteins c-met; Structure-Activity Relationship; Tumor Cells, Cultured

As a natural antioxidant, verbascoside (VB) is proved to be a promising method for the treatment of oxidative-stress-related neurodegenerative diseases. Thus, this study aimed to investigate the effects of VB on glioblastoma cell proliferation, apoptosis, migration, and invasion as well as the mechanism involving signal transducer and activator of transcription 3 (STAT3) and Src homology 2 domain-containing protein tyrosine phosphatase 1 (SHP-1).. U87 cells were assigned to different treatments. The MTT assay was used to test cell proliferation, flow cytometry was used to detect cell apoptosis, and a Transwell assay was used for cell migration and invasion. We analyzed the glioblastoma tumor growth in a xenograft mouse model. Western blot analysis was employed to determine the protein expression of related genes.. Glioblastoma cells exhibited decreased cell proliferation, migration, invasion, and increased apoptosis when treated with VB or TMZ. Western blot analysis revealed elevated SHP-1 expression and reduced phosphorylated (p)-STAT3 expression in glioblastoma cells treated with VB compared with controls. Correspondingly, in a xenograft mouse model treated with VB, glioblastoma tumor volume and growth were decreased. Glioblastoma xenograft tumors treated with VB showed elevated SHP-1, Bax, cleaved caspase-3, and cleaved PARP expression and reduced p-STAT3, Bcl-2, survivin, MMP-2, and MMP-9 expression. siRNA-SHP-1 inhibited the VB effects on glioblastoma.. This study demonstrates that VB inhibits glioblastoma cell proliferation, migration, and invasion while promoting apoptosis via SHP-1 activation and inhibition of STAT3 phosphorylation.

Topics: Animals; Apoptosis; Cell Line, Tumor; Cell Movement; Cell Proliferation; Female; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Neoplastic; Glioblastoma; Glucosides; Humans; Mice; Mice, Inbred BALB C; Mice, Nude; Neoplasm Metastasis; Neoplasm Proteins; Phenols; Protein Tyrosine Phosphatase, Non-Receptor Type 6; STAT3 Transcription Factor; Up-Regulation; Xenograft Model Antitumor Assays