The methylation status of the platelet-derived growth factor-B gene promoter and its regulation of cellular proliferation following folate treatment in human glioma cells

Plasma extracellular vesicles proteomics in meningioma patients

Tumor derived Extracellular vesicles (EVs) in circulating system may contain tumor-specific markers, and EV detection in body fluids could become an important tool for early tumor diagnosis, prognosis assessment. Meningiomas are the most common benign intracranial tumors, few studies have revealed specific protein markers for meningiomas from patients' body fluids. In this study, using proximity labeling technology and non-tumor patient plasma as a control, we detected protein levels of EVs in plasma samples from meningioma patients before and after surgery. Through bioinformatics analysis, we discovered that the levels of EV count and protein count in meningioma patients were significantly higher than those in healthy controls, and were significantly decreased postoperatively. Among EV proteins in meningioma patients, the levels of MUC1, SIGLEC11, E-Cadherin, KIT, and TASCTD2 were found not only significantly elevated than those in healthy controls, but also significantly decreased after tumor resection. Moreover, using publicly available GEO databases, we verified that the mRNA level of MUC1, SIGLEC11, and CDH1 in meningiomas were significantly higher in comparison with normal dura mater tissues. Additionally, by analyzing human meningioma specimens collected in this study, we validated the protein levels of MUC1 and SIGLEC11 were significantly increased in WHO grade 2 meningiomas and were positively correlated with tumor proliferation levels. This study indicates that meningiomas secret EV proteins into circulating system, which may serve as specific markers for diagnosis, malignancy predicting and tumor recurrent assessment.

The role and clinical relevance of long non-coding RNAs in glioma

Glioma represents a complex and heterogeneous disease, posing significant challenges to both clinicians and researchers. Despite notable advancements in glioma treatment, the overall survival rate for most glioma patients remains dishearteningly low. Hence, there is an urgent necessity to discover novel biomarkers and therapeutic targets specifically tailored for glioma. In recent years, long non-coding RNAs (lncRNAs) have emerged as pivotal regulators of gene expression and have garnered attention for their involvement in the development and progression of various cancers, including glioma. The dysregulation of lncRNAs plays a critical role in glioma pathogenesis and influences clinical outcomes. Consequently, there is growing interest in exploring the potential of lncRNAs as diagnostic and prognostic biomarkers, as well as therapeutic targets. By understanding the functions and dysregulation of lncRNAs in glioma, researchers aim to unlock new avenues for the development of innovative treatment strategies catered to glioma patients. The identification and thorough characterization of lncRNAs hold the promise of novel therapeutic approaches that could potentially improve patient outcomes and enhance the management of glioma, ultimately striving for better prospects and enhanced quality of life for those affected by this challenging disease. The primary objective of this paper is to comprehensively review the current state of knowledge regarding lncRNA biology and their intricate roles in glioma. It also delves into the potential of lncRNAs as valuable diagnostic and prognostic indicators and explores their feasibility as promising targets for therapeutic interventions.

Long non-coding RNA RP5-821D11.7 promotes proliferation, migration, and epithelial-mesenchymal transition in glioma and glioma stem-like cells

Long noncoding RNA (lncRNA) has been recently revealed as a main regulatory molecule, which implicates many cellular functions. Studies showed that lncRNA abnormally expressed and involved in the progression and tumorigenesis of glioma. Present study identified a novel lncRNA associated with glioma, glioma stem-like cells (GSCs), and then revealed their potential functions. During the screening of lncRNAs, we investigated overexpression of lncRNA RP5-821D11.7 (lncRNA-RP5) in GSCs compared to glioma cells. Lentivirus-mediated shRNA for lncRNA-RP5 was constructed and transfected into glioma cells. Transfected stable glioma cells were transplanted into nude mice and tumor growth was observed. Knockdown of lncRNA-RP5 significantly inhibits proliferation, colony formation, migration and reduces epithelial-mesenchymal transition (EMT) by activating the Wnt/β-catenin pathway. Additionally, the results showed that lncRNA RP5 knockdown enhances cell apoptosis through endoplasmic reticulum stress. Therefore, this study may provide a better understanding about lncRNA-RP5 which revealed that it might be a potential therapeutic target in case of glioma progression and recurrence.

Biological Characterization and Therapeutics for Subscalp Recurrent in Intracranial Glioblastoma

Purpose

Gliomas are common intracranial tumors, of which 70% are malignant gliomas. Glioblastoma multiforme (GBM) is the most aggressive tumor, and patients with GBM have a median survival time of only 9–12 months; extracranial recurrence of GBM is very rare. A therapeutic strategy for this kind of recurrent tumor is lacking.

Materials and Methods

We present a case of a patient with extracranial recurrence of subscalp GBM. The subscalp tumor was resected and xenotransplanted into BALB/C nude mice. Then, glioma cells were isolated from the xenograft models and passaged in vitro. HE staining, immunohistochemistry, CCK-8 assays, karyotypic analysis, short tandem repeat STR analysis and flow cytometry were used to analyze the biological characteristics and malignant phenotype of these established cells. The cells and xenografts were then used as preclinical models to evaluate the antitumor efficacy of oncolytic herpes simplex virus 1 (oHSV-1).

Results

The isolated cells, which were named BT-01, were positive for Nestin and GFAP. The main characteristics of BT-01 cells were that they harbored glioblastoma stem-like cells (GSCs) and that they possessed highly aggressive migration capacities compared with the existing cell lines U87-MG and U251-MG. Moreover, BT-01 cells tolerated the chemotherapeutic drug temozolomide. Our study showed that oHSV-1 could replicate in and repress the growth of BT-01 cells and significantly inhibit tumor growth in xenograft models.

Conclusion

Taken together, our results showed that a new recurrent glioblastoma cell line was established, which can be useful for research on recurrent glioblastoma. We provided a reliable preclinical model to evaluate the antitumor efficacy of oHSV-1 in vivo and a promising therapy for recurrent GBM.

IGFBP5 increases cell invasion and inhibits cell proliferation by EMT and Akt signaling pathway in Glioblastoma multiforme cells

Background

Recurrence of Glioblastoma multiforme (GBM) seems to be the rule despite combination therapies. Cell invasion and cell proliferation are major reasons for recurrence of GBM. And insulin-like growth factor binding protein 5 (IGFBP5) is the most conserved of the IGFBPs and is frequently dysregulated in cancers and metastatic tissues.

Results

By studying the human glioma tissues, we find that IGFBP5 expression associate to the histopathological classification and highly expressed in GBM. Using IGFBP5 mutants we demonstrate that knockdown of IGFBP5 inhibited cell invasion, whereas promoting cell proliferation in GBM cells. Mechanistically, we observed that promoting GBM cell proliferation by inhibiting IGFBP5 was associated with stimulating Akt (Protein kinase B) phosphorylation. However, IGFBP5 promote GBM cell invasion was related to the epithelial-to-mesenchymal transition (EMT). Furthermore, the Chinese Glioma Genome Altas (CGGA) database show that IGFBP5 is significantly increased in recurrent glioma and it predicted worse survival.

Conclusions

The obtained results indicate that IGFBP5 has two sides in GBM—inhibiting cell proliferation but promoting cell invasion.

LGR5, a novel functional glioma stem cell marker, promotes EMT by activating the Wnt/β-catenin pathway and predicts poor survival of glioma patients

Background

Tumor recurrence, the chief reason for poor prognosis of glioma, is largely attributed to glioma stem cells (GSCs) and epithelial-mesenchymal transition (EMT). However, the mechanisms among them remain unknown. Here, we determined whether leucine-rich repeat-containing G protein-coupled receptor 5 (LGR5), known as a stem cell marker for colon cancer and gastric cancer, can serve as a novel GSC marker involved in EMT and a therapeutic target in glioma.

Methods

Stemness properties were examined in FACS-isolated LGR5⁺/LGR5⁻ cells. Reported stem cell markers, EMT and the Wnt/β-catenin pathway were examined in stable LGR5 knockdown or overexpressed GSCs by Western Blot. The treatment experiment was performed in an intracranial orthotopic xenograft model by knockdown of LGR5 or by using the Wnt/β-catenin pathway inhibitor Wnt-C59. LGR5 expression was determined in 268 glioma specimens by immunohistochemistry.

Results

LGR5⁺ cells possessed stronger stemness properties compared to LGR5⁻ cells. The expression of SOX2, Nanog, CD133, CD44, CD24 and EpCAM was modulated by LGR5. Both LGR5 knockdown and Wnt-C59 reduced tumor invasion and migration and blocked EMT by inhibiting the Wnt/β-catenin pathway in vitro and suppressed the intracranial orthotopic xenograft growth and prolonged the survival of xenograft mice in vivo. Moreover, LGR5 was positively correlated with Ki67, N-cadherin and WHO grade and negatively correlated with IDH1. Glioma patients with high expression of LGR5 showed significantly poorer prognosis.

Conclusions

LGR5 is a new functional GSC marker and prognostic indicator that can promote EMT by activating the Wnt/β-catenin pathway and would thus be a novel therapeutic target for glioma.

Electronic supplementary material

The online version of this article (10.1186/s13046-018-0864-6) contains supplementary material, which is available to authorized users.

Overexpression of STAT1 suppresses angiogenesis under hypoxia by regulating VEGF‑A in human glioma cells

Hypoxia is common in Glioblastoma (GBM). By regulating the 'hypoxia signaling cascade', hypoxia affects several processes including cell proliferation, invasion, and angiogenesis. Some studies have revealed that signal transducer and activator of transcription (STAT), including STAT1, is abnormal under hypoxia in several cancers. Here, we investigated the role of STAT1 under hypoxia in glioma progression. We found that STAT1 was downregulated under a hypoxic condition in U251 and U373. STAT1 overexpression can not only decrease proliferation, migration and invasion in U251 and U373 but also inhibit tube formation of HBMECs. Moreover, overexpression of STAT1 decreased tumor growth and prolonged the overall survival of xenograft mice. We also showed that STAT1 overexpression inhibited the expression of HIF-1α and VEGF-A. Our work suggests that STAT1 plays a pivotal role as a tumor suppressor in glioma under hypoxia, and it could be a potential new therapeutic target in glioma.

Ferritin heavy chain as a molecular imaging reporter gene in glioma xenografts

PURPOSE

The development of glioma therapy in clinical practice (e.g., gene therapy) calls for efficiently visualizing and tracking glioma cells in vivo. Human ferritin heavy chain is a novel gene reporter in magnetic resonance imaging. This study proposes hFTH as a reporter gene for MR molecular imaging in glioma xenografts.

METHODS

Rat C6 glioma cells were infected by packaged lentivirus carrying hFTH and EGFP genes and obtained by fluorescence-activated cell sorting. The iron-loaded ability was analyzed by the total iron reagent kit. Glioma nude mouse models were established subcutaneously and intracranially. Then, in vivo tumor bioluminescence was performed via the IVIS spectrum imaging system. The MR imaging analysis was analyzed on a 7T animal MRI scanner. Finally, the expression of hFTH was analyzed by western blotting and histological analysis.

RESULTS

Stable glioma cells carrying hFTH and EGFP reporter genes were successfully obtained. The intracellular iron concentration was increased without impairing the cell proliferation rate. Glioma cells overexpressing hFTH showed significantly decreased signal intensity on T2-weighted MRI both in vitro and in vivo. EGFP fluorescent imaging could also be detected in the subcutaneous and intracranial glioma xenografts. Moreover, the expression of the transferritin receptor was significantly increased in glioma cells carrying the hFTH reporter gene.

CONCLUSION

Our study illustrated that hFTH generated cellular MR imaging contrast efficiently in glioma via regulating the expression of transferritin receptor. This might be a useful reporter gene in cell tracking and MR molecular imaging for glioma diagnosis, gene therapy and tumor metastasis.

Inhibition of fatty acid synthase suppresses neovascularization via regulating the expression of VEGF-A in glioma

PURPOSE

Fatty acids (FAs) are essential for membrane lipids biosynthesis and energy consumption in cancer cells. De novo FAs synthesis is catalyzed by fatty acid synthase (FASN), which is overexpressed and correlates with histological grade in glioma. Herein, we focused on the role of FASN in glioma neovascularization.

METHODS

The expression levels of FASN, Ki67 and CD34 were determined using immunohistochemistry (IHC). FASN specific-targeted shRNA and C75 were applied to evaluate the influence of FASN on glioma stem cell proliferation, migration and tube formation ability in vitro. An intracranial glioma model was established to study the effects of FASN on tumor growth and neovascularization in vivo.

RESULTS

IHC staining showed that the expression level of FASN correlated with tumor grade, Ki67 levels and microvessels density (MVD) in human gliomas. Inhibition of FASN using shRNAs or C75 decreased tumor growth, prolonged the overall survival of xenograft mice and decreased MVD in brain tumor sections. Moreover, inhibition of FASN blocked hypoxia-inducible factor-1α (HIF-1α)/vascular endothelial growth factor A (VEGF-A) signaling and upregulated the anti-angiogenic isoform-VEGF165b.

CONCLUSION

Our results suggest that FASN plays a pivotal role in glioma neovascularization, and inhibition of FASN may be a potential target for anti-angiogenic therapy for glioma.

Mechanisms of PDGF siRNA-mediated inhibition of bone cancer pain in the spinal cord

Patients with tumors that metastasize to bone frequently suffer from debilitating pain, and effective therapies for treating bone cancer are lacking. This study employed a novel strategy in which herpes simplex virus (HSV) carrying a small interfering RNA (siRNA) targeting platelet-derived growth factor (PDGF) was used to alleviate bone cancer pain. HSV carrying PDGF siRNA was established and intrathecally injected into the cavum subarachnoidale of animals suffering from bone cancer pain and animals in the negative group. Sensory function was assessed by measuring thermal and mechanical hyperalgesia. The mechanism by which PDGF regulates pain was also investigated by comparing the differential expression of pPDGFRα/β and phosphorylated ERK and AKT. Thermal and mechanical hyperalgesia developed in the rats with bone cancer pain, and these effects were accompanied by bone destruction in the tibia. Intrathecal injection of PDGF siRNA and morphine reversed thermal and mechanical hyperalgesia in rats with bone cancer pain. In addition, we observed attenuated astrocyte hypertrophy, down-regulated pPDGFRα/β levels, reduced levels of the neurochemical SP, a reduction in CGRP fibers and changes in pERK/ERK and pAKT/AKT ratios. These results demonstrate that PDGF siRNA can effectively treat pain induced by bone cancer by blocking the AKT-ERK signaling pathway.