Formation of new lymphatic vessels in glioma: An immunohistochemical analysis

Glucose regulates the HMGB1 signaling pathway through SIRT1 in glioma

BACKGROUND

Glucose is a fundamental substance for numerous cancers, including glioma. However, its influence on tumor cells regulatory mechanisms remains uncertain. SIRT1 is a regulator of deacetylation and a key player in the progression of malignant tumors. The objective of this study was to examine the role of glucose and SIRT1 in glioma.

METHODS

This study investigated the association of SIRT1 expression with clinicopathological features and prognosis in glioma patients using the TCGA database. The Western blotting technique was used to identify the expression of SIRT1 protein in glioma cells. The study also examined the impact of differing glucose concentrations on the biological functions of glioma cells. The study investigated the expression of SIRT1 and HMGB1 signaling pathways in glioma. Additionally, resilience experiments were conducted utilizing SRT1720.

RESULTS

SIRT1 is a gene that suppresses tumors and is low expressed in gliomas. Low expression of this gene is strongly linked to a poor prognosis in patients with glioma. High concentrations of glucose can promote the proliferation, migration, and invasion of glioma cells, while also inhibiting apoptosis. The findings of this mechanistic study provide evidence that glucose can down-regulate SIRT1 expression, leading to increased levels of acetylated HMGB1. This in turn promotes the ex-nuclear activation of HMGB1 and associated signaling pathways, ultimately driving glioma malignancy.

CONCLUSION

Glucose has the ability to regulate the HMGB1 associated signaling pathway through SIRT1, thus promoting glioma progression. This holds significant research value.

The spectrum of microvascular patterns in adult diffuse glioma and their correlation with tumor grade

BACKGROUND

Primary brain tumors constitute the leading cause of cancer-related mortality. Among them, adult diffuse gliomas are the most common type, affecting the cerebral hemispheres and displaying a diffuse infiltrative pattern of growth in the surrounding neuropil that accounts for about 80% of all primary intracranial tumors. The hallmark feature of gliomas is blood vessel proliferation, which plays an important role in tumor growth, tumor biological behavior, and disease outcome. High-grade gliomas exhibit increased vascularity, the worst prognosis, and lower survival rates. Several angiogenic receptors and factors are upregulated in glioblastomas and stimulate angiogenesis signaling pathways by means of activating oncogenes and/or down-regulating tumor-suppressor genes. Existing literature has emphasized that different microvascular patterns (MVPs) are displayed in different subtypes of adult diffuse gliomas.

METHODS

We examined the distribution and biological characteristics of different MVPs in 50 patients with adult diffuse gliomas. Haematoxylin and eosin staining results, along with periodic acid-Schiff and CD34 dual-stained sections, were examined to assess the vascular patterns and correlate with different grades of diffuse glioma.

RESULTS

The present observational study on adult diffuse glioma evaluated tumor grade and MVPs. Microvascular sprouting was the most common pattern, while a bizarre pattern (type 2) was associated with the presence of a high-grade glioma. Vascular mimicry was observed in 6% of cases, all of which were grade 4 gliomas.

CONCLUSIONS

This study supplements the role of neo-angiogenesis and aberrant vasculature patterns in the grading and progression of adult diffuse gliomas, which can be future targets for planning treatment strategies.

Downregulation of ADAMTS3 Suppresses Stemness and Tumorigenicity in Glioma Stem Cell

AIMS

Glioblastoma multiforme (GBM) is the most aggressive type of human brain tumor, with a poor prognosis and a median overall survival of fewer than 15 months. Glioma stem cells (GSCs) have recently been identified as a key player in tumor initiation and therapeutic resistance in GBM. ADAMTS family of metalloproteinases is known to cleave a wide range of extracellular matrix substrates and has been linked to tissue remodeling events in tumor development. Here, we investigate that ADAMTS3 regulates GSC proliferation and self-renewal activities, and tumorigenesis in orthotopic xenograft models.

METHODS

ADAMTS3 mRNA expression levels in normal human astrocyte (NHA), glioma, and GSCs cell lines were compared. After knockdown of ADAMTS3, alamarBlue assay, in vitro limiting dilution, and orthotopic xenograft assays were performed. To investigate the tumor-associated roles of ADAMTS3, several statistical assays were conducted using publicly available datasets.

RESULTS

ADAMTS3 level was remarkably higher in GSCs than in NHA, glioma cell lines, and their matched differentiated tumor cells. Interestingly, knockdown of ADAMTS3 disrupted GSC's proliferation, self-renewal activity, and tumor formation in vivo. Furthermore, ADAMTS3 could be used as an independent predictor of malignancy progression in GBM.

CONCLUSION

We identified ADAMTS3 as a potential therapeutic target for GBM.

Prognostic significance of HIF1-α immunohistochemical expression in gliomas and it's relation to IDH1 mutation status

Background

Gliomas are the commonest primary adults’ brain tumors. Hypoxia performs an essential role in gliomas’ initiation as well as progression through hypoxia inducible factor (HIF-1α) activation, which could serve as a promising target in treatment of gliomas. Our study aimed to evaluate types and grades of glioma cases and detect isocitrate dehydrogenase 1 (IDH1) mutation status and expression of HIF-1α in all included cases and its correlation with clinical data and pathological parameters.

Results

Samples from 71 patients who were diagnosed with glioma were studied immunohistochemically for IDH1-R132H (if indicated) and HIF-1α expression. Expression of HIF-1α was detected in 73.2% of the included 71 gliomas. HIF-1α expression significantly increased in older patients, in high-grade gliomas and in tumors positive for necrosis. We studied IDH1 mutation in the histologically diagnosed grade 2, 3and 4 astrocytic and oligodendroglial tumors (51 cases out of the included 71 gliomas). IDH1-R132H immunohistochemical expression was positive in 62.7% of cases. IDH1 mutation was significantly higher with younger age. IDH1 mutation was noted also with lower tumor grade. A statistically significant relation was detected between negative IDH1-R132H expression and high level of HIF-1α immunohistochemical expression.

Conclusion

Absence of IDH1 mutation with increased HIF-1α expression among high-grade gliomas suggesting both as predicting indicators for poor prognosis.

The Role of Lymphatic Marker Prox-1 in Relation to Brain Tumours

The homeobox gene, Prox-1 is a transcription factor essential for lymphatic development (lymphangiogenesis) during embryogenesis. It also performs different functions in various tissues such as: retina, lens, liver, pancreas and the central nervous system. Intense expression of Prox-1 has been demonstrated in the developing spinal cord and brain. In adulthood its expression continues in the hippocampus and cerebellum. In adult tissues the process of lymphatic vasculature formation is accompanied under certain pathological conditions such as inflammation, tissue repair and tumour growth. Prox-1 expression is typical for lymphatic vessels; thus it belongs to one of the most specific and widely used mammalian lymphatic endothelial marker in the detection of lymphangiogenesis and lymphatic vessel invasion in oncogenesis. It has been shown that Prox-1 is involved in cancer development and progression. It’s tumour suppressive and oncogenic properties are proven in several human cancers, including brain tumours. Among all body cancers the brain tumours represent the most feared tumours with very limited treatment options and a poor diagnosis. The aim of this paper was to show the current knowledge of the gene Prox-1 with an emphasis on brain tumours, especially in gliomas.

Role of Borneol Induced Autophagy in Enhancing Radiosensitivity of Malignant Glioma

Glioma is the common primary craniocerebral malignancy with unfavorable prognosis. It is currently treated by surgical resection supplemented by radiotherapy, although the resistance of glioma cells to radiation limits the therapeutic outcomes. The aim of the present study was to determine the potential radiosensitizing effects of borneol and the underlying mechanisms. We found that borneol administration along with radiotherapy significantly inhibited the growth of primary glioma cells in vitro and in vivo. Furthermore, borneol markedly increased the number of autophagosomes in the glioma cells, which coincided with increased expression of beclin-1 and LC3. And the combination of borneol and radiation exposure significantly decreased the expression levels of HIF-1α, mTORC1 and eIF4E. In addition, silencing mTORC1 and eIF4E upregulated Beclin-1 and LC3 and decreased the expression of HIF-1α, thereby inhibiting tumor cell proliferation. Our findings suggest that borneol sensitizes glioma cells to radiation by inducing autophagy via inhibition of the mTORC1/eIF4E/HIF-1α regulatory axis.

New lymphatic cell formation is associated with damaged brain tissue clearance after penetrating traumatic brain injury

We characterized the tissue repair response after penetrating traumatic brain injury (pTBI) in this study. Seventy specific pathogen-free Kunming mice were randomly divided into the following groups: normal control, 1, 3, 7, 15, 21, and 30 days after pTBI. Hematoxylin and eosin (H&E) staining, immunohistochemistry, and immunofluorescence were performed to examine and monitor brain tissue morphology, and the distribution and expression of lymphatic-specific markers lymphatic vessel endothelial receptor-1 (LYVE-1), hematopoietic precursor cluster of differentiation 34 (CD34) antigen, and Prospero-related homeobox-1 (PROX1) protein. H&E staining revealed that damaged and necrotic tissues observed on day 1 at and around the injury site disappeared on day 7, and there was gradual shrinkage and disappearance of the lesion on day 30, suggesting a clearance mechanism. We explored the possibility of lymphangiogenesis causing this clearance as part of the post-injury response. Notably, expression of lymphangiogenesis markers LYVE-1, CD34, and PROX1 was detected in damaged mouse brain tissue but not in normal tissue. Moreover, new lymphatic cells and colocalization of LYVE-1/CD34 and LYVE-1/PROX1 were also observed. Our findings of the formation of new lymphatic cells following pTBI provide preliminary insights into a post-injury clearance mechanism in the brain. Although we showed that lymphatic cells are implicated in brain tissue repair, further research is required to clarify the origin of these cells.