Cellular and Molecular Comparison of Glioblastoma Multiform Cell Lines

Expression, Prognostic Value, and Biological Function of CTHRC1 in Different Types of Gliomas: A Bioinformatic Analysis and Experiment Validation

Background

In recent years, abnormal expression of collagen triple helix repeat containing 1 (CTHRC1) has been found in some tumors, closely related to the poor prognosis of cancer patients. However, the clinical significance of CTHRC1 in gliomas is not completely understood.

Methods

We investigated the expression, prognostic value, and potential biological function of CTHRC1 in different types of gliomas through bioinformatics analysis and experimental verification.

Results

Bioinformatics analysis revealed several key findings regarding the expression and clinical significance of CTHRC1 in gliomas. First, the analysis demonstrated a positive correlation between CTHRC1 expression and the World Health Organization (WHO) grading of gliomas, a relationship that was validated through immunohistochemistry experiments. In addition, a trend was observed in which CTHRC1 expression increased with the extent of glioma invasion, as supported by Western blot experiments. Subsequent bioinformatics analysis identified the mesenchymal subtype of gliomas as having the highest levels of CTHRC1 expression, a finding reinforced by immunohistochemical staining. Moreover, high CTHRC1 expression was associated with poor prognosis in gliomas and emerged as an independent prognostic factor, with varying impacts on prognosis between low-grade gliomas (LGGs) and glioblastoma (GBM) subgroups. Notably, comparative analysis unveiled distinct patterns of immune infiltration of CTHRC1 in LGG and GBM. Furthermore, alterations in copy number variations and DNA methylation were identified as potential mechanisms underlying elevated CTHRC1 levels in gliomas. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis indicated that CTHRC1 and its associated genes mainly function in the extracellular matrix and participate in tumor-related signaling pathways.

Conclusions

The CTHRC1 has shown significant clinical utility as a prognostic marker and mesenchymal subtype marker of glioma.

Immunogenic cell death mediated TLR3/4-activated MSCs in U87 GBM cell line

Background and aims

Glioblastoma (GBM) is an aggressive primary brain cancer with no promising curative therapies. It has been indicated that MSCs can interact with the tumour microenvironment (TME) through the secretion of soluble mediators regulating intercellular signalling within the TME. TLRs are a multigene family of pattern recognition receptors with evolutionarily conserved regions and are widely expressed in immune and other body cells. MSCs by TLRs can recognize conserved molecular components (DAPMPs and PAPMPs) and activate signalling pathways, which regulate immune and inflammatory responses. MSCs may exert immunomodulatory functions through interaction with their expressed toll-like receptors (TLRs) and exert a protective effect against tumour antigens. As an emerging approach, we aimed to monitor the U87 cell line growth, migration and death markers following specific TLR3/4-primed-MSCs-CMs treatment.

Methods and results

We investigated the phenotypic and functional outcomes of primed-CMs and glioma cell line co-culture following short-term, low-dose TLR3/4 priming. The gene expression profile of target genes, including apoptotic markers and related genes, was analyzed by qRT-PCR. MicroRNA-Seq examined the miRNA expression patterns, and flow cytometry evaluated the cell viability and cycle stages. The results showed significant changes in apoptosis and likely necroptosis-related markers following TLR3/4-primed-MSCs-CMs exposure in the glioma cell line. Notably, we observed a considerable induction of selective pro-apoptotic markers and both the early and late stages of apoptosis in treated U87 cell lines. Additionally, the migration rate of glioma cells significantly decreased following MSCs-CM treatment.

Conclusion

Our findings confirmed that the exposure of TLR3/4-activated-MSCs-CMs with glioma tumour cells possibly changes the immunogenicity of the tumour microenvironment and induces immunogenic programmed cell death. Our results can support the idea that TLR3/4-primed-MSCs can lead to innate immune-mediated cell death and modify tumour cell biology in invasive and metastatic cancers.

UTX inhibition suppresses proliferation and promotes apoptosis in patient-derived glioblastoma stem cells by modulating periostin expression

Glioblastoma stem cells (GSCs) exert a crucial influence on glioblastoma (GBM) development, progression, resistance to therapy, and recurrence, making them an attractive target for drug discovery. UTX, a histone H3K27 demethylase, participates in regulating multiple cancer types. However, its functional role in GSCs remains insufficiently explored. This study aims to investigate the role and regulatory mechanism of UTX on GSCs. Analysis of TCGA data revealed heightened UTX expression in glioma, inversely correlating with overall survival. Inhibiting UTX suppressed GBM cell growth and induced apoptosis. Subsequently, we cultured primary GSCs from three patients, observing that UTX inhibition suppressed cell proliferation and induced apoptosis. RNA-seq was performed to analyze the gene expression changes after silencing UTX in GSCs. The results indicated that UTX-mediated genes were strongly correlated with GBM progression and regulatory tumor microenvironment. The transwell co-cultured experiment showed that silencing UTX in the transwell chamber GSCs inhibited the well plate cell proliferation. Protein-protein interaction analysis revealed that periostin (POSTN) played a role in the UTX-mediated transcriptional regulatory network. Replenishing POSTN reversed the effects of UTX inhibition on GSC proliferation and apoptosis. Our study demonstrated that UTX inhibition hindered POSTN expression by enhancing the H3K27me2/3 level, eventually resulting in inhibiting proliferation and promoting apoptosis of patient-derived GSCs. Our findings may provide a novel and effective strategy for the treatment of GBM.

GTF2E2 downregulated by miR-340-5p inhibits the malignant progression of glioblastoma

Glioblastoma is the most common malignant tumor in the central nervous system. The general transcription factor IIE subunit beta (GTF2E2) is crucial for physiological and pathological functions, but its roles in the malignant biological function of glioma remain ambiguous. CCK-8, colony formation assays, TUNEL assays, cell migration assays, wound-healing assays, and xenograft model were established to investigate the biological functions of GTF2E2 both in vitro and in vivo. GTF2E2 was overexpressed in glioma and was associated with poor prognosis of glioma patients. Biological functions of GTF2E2 were investigated both in vitro and in vi0vo by multiple experiments. Moreover, we explored the possible mechanisms of GTF2E2. In our results, we demonstrated that GTF2E2 could be regulated by miR-340-5p directly or indirectly. CCND1 was transcriptionally affected by GTF2E2 and glioma progression was then regulated. Our data presented the overexpression of GTF2E2 in glioma and indicated the association between GTF2E2 and glioma prognosis. GTF2E2 was found to be regulated by miR-340-5p and thus affect downstream gene expressions and glioma progression. Our results indicate that GTF2E2 might be a potential target in the diagnosis and treatments of glioblastoma.

Rnd3 Is a Crucial Mediator of the Invasive Phenotype of Glioblastoma Cells Downstream of Receptor Tyrosine Kinase Signalling

Enhanced invasiveness is one of the defining biological traits of glioblastoma cells, which exhibit an infiltrative nature that severely hinders surgical resection. Among the molecular lesions responsible for GBM aggressiveness, aberrant receptor tyrosine kinase (RTK) signalling is well-characterised. Enhanced RTK signalling directly impacts a myriad of cellular pathways and downstream effectors, which include the Rho GTPase family, key regulators of actin cytoskeletal dynamics. Here, we have analysed the functional crosstalk between oncogenic signals emanating from RTKs and Rho GTPases and focused on the specific contribution of Rnd3 to the invasive phenotype of GBM in this context. We found that RTK inhibition with a panel of RTK inhibitors decreased cell motility and cell invasion and promoted dramatic actin cytoskeleton reorganisation through activation of the RhoA/Rho-associated protein kinase 1 (ROCK) axis. RTK inhibition also significantly decreased Rnd3 expression levels. Consistently, shRNA-mediated Rnd3 silencing revealed that Rnd3 depletion promoted substantial changes in the actin cytoskeleton and reduced cell motility and invasion capacity, recapitulating the effects observed upon RTK inhibition. Our results indicate that Rnd3 is a crucial mediator of RTK oncogenic signalling involved in actin cytoskeletal reorganisation, which contributes to determining the invasive phenotype of GBM cells.