Glioma is the most common intracranial malignant tumor, and the current main standard treatment option is a combination of tumor surgical resection, chemotherapy and radiotherapy. Due to the terribly poor five-year survival rate of patients with gliomas and the high recurrence rate of gliomas, some new and efficient therapeutic strategies are expected. Recently, ferroptosis, as a new form of cell death, has played a significant role in the treatment of gliomas. Specifically, studies have revealed key processes of ferroptosis, including iron overload in cells, occurrence of lipid peroxidation, inactivation of cysteine/glutathione antiporter system Xc⁻ (xCT) and glutathione peroxidase 4 (GPX4). In the present review, we summarized the molecular mechanisms of ferroptosis and introduced the application and challenges of ferroptosis in the development and treatment of gliomas. Moreover, we highlighted the therapeutic opportunities of manipulating ferroptosis to improve glioma treatments, which may improve the clinical outcome.

Background: In the tumor immune microenvironment (TIME), triggering receptor expressed on myeloid cells 2 (trem2) is widely considered to be a crucial molecule on tumor-associated macrophages(TAMs). Multiple studies have shown that trem2 may function as an immune checkpoint in various malignant tumors, mediating tumor immune evasion. However, its specific molecular mechanisms, especially in glioma, remain elusive. Methods: Lentivirus was transfected to establish cells with stable knockdown of trem2. A Transwell system was used for segregated coculture of glioma cells and microglia. Western blotting, quantitative real-time polymerase chain reaction (qRT‒PCR), and immunofluorescence (IF) were used to measure the expression levels of target proteins. The proliferation, invasion, and migration of cells were detected by colony formation, cell counting kit-8 (CCK8), 5-ethynyl-2’-deoxyuridine (EdU) and transwell assays. The cell cycle, apoptosis rate and reactive oxygen species (ROS) level of cells were assessed using flow cytometry assays. The comet assay and tube formation assay were used to detect DNA damage in glioma cells and angiogenesis activity, respectively. Gl261 cell lines and C57BL/6 mice were used to construct the glioma orthotopic transplantation tumor model. Results: Trem2 was highly overexpressed in glioma TAMs. Knocking down trem2 in microglia suppressed the growth and angiogenesis activity of glioma cells in vivo and in vitro. Mechanistically, knockdown of trem2 in microglia promoted proinflammatory microglia and inhibited anti-inflammatory microglia by activating jak2/stat1 and inhibiting the NF-κB p50 signaling pathway. The proinflammatory microglia produced high concentrations of nitric oxide (NO) and high levels of the proinflammatory cytokines TNF-α, IL-6, and IL-1β, and caused further DNA damage and promoted the apoptosis rate of tumor cells. Conclusions: Our findings revealed that trem2 in microglia plays a significant role in the TIME of gliomas. Knockdown of trem2 in microglia might help to improve the efficiency of inhibiting glioma growth and delaying tumor progression and provide new ideas for further treatment of glioma.

Objective: The aim of this study is to critically appraise whether published systematic reviews/meta-analyses of traditional Chinese medicine for adults with ischemic stroke are of sufficient quality and to rate the quality of evidence using the Grading of Recommendations, Assessment, Development, and Evaluation approach.Method: A literature search was performed in the Cochrane Library, PubMed, Chinese National Knowledge Infrastructure, and SinoMed databases by March 2022. The inclusion criteria were systematic reviews/meta-analyses of traditional Chinese medicine in adults who suffered from ischemic stroke. A Measurement Tool to Access Systematic Reviews 2 (AMSTAR-2) and Preferred Reporting Items for Systematic Reviews and Meta-Analyses for Abstract (PRISMA-A) statements were used to assess the methodological and reporting quality of the included reviews. The Grading of Recommendations, Assessment, Development, and Evaluation system was utilized to assess each report’s evidence level.Results: Of the 1,908 titles and abstracts, 83 reviews met the inclusion criteria. These studies were published between 2005 and 2022. The results of AMSTAR-2 showed that 51.4% of the items were reported, but the registration, reasons for the inclusion of study design, the list of excluded studies, and funding information were ignored in the majority of the reviews. The results of PRISMA-A showed that 33.9% of items were reported, and the information on registration, limitation, and funding was not available in many publications. The assessment of the evidence with the Grading of Recommendations, Assessment, Development, and Evaluation showed that more than half (52/83) of the included studies had either low or very low levels of evidence.Conclusion: The reporting quality in the abstract of systematic reviews/meta-analyses on traditional Chinese medicine for ischemic stroke is poor and does not facilitate timely access to valid information for clinical practitioners. Although the methodological quality is of a medium level, this evidence lacks certainty, especially with a high risk of bias in individual studies.