During metabolic reprogramming, glioma cells and their initiating cells efficiently utilized carbohydrates, lipids and amino acids in the hypoxic lesions, which not only ensured sufficient energy for rapid growth and improved the migration to normal brain tissues, but also altered the role of immune cells in tumor microenvironment. Glioma cells secreted interferential metabolites or depriving nutrients to injure the tumor recognition, phagocytosis and lysis of glioma-associated microglia/macrophages (GAMs), cytotoxic T lymphocytes, natural killer cells and dendritic cells, promoted the expansion and infiltration of immunosuppressive regulatory T cells and myeloid-derived suppressor cells, and conferred immune silencing phenotypes on GAMs and dendritic cells. The overexpressed metabolic enzymes also increased the secretion of chemokines to attract neutrophils, regulatory T cells, GAMs, and dendritic cells, while weakening the recruitment of cytotoxic T lymphocytes and natural killer cells, which activated anti-inflammatory and tolerant mechanisms and hindered anti-tumor responses. Therefore, brain-targeted metabolic therapy may improve glioma immunity. This review will clarify the metabolic properties of glioma cells and their interactions with tumor microenvironment immunity, and discuss the application strategies of metabolic therapy in glioma immune silence and escape.

Introduction Hydroxychloroquine (HCQ), 4-aminoquinoline, is an antimalarial drug and has become a basic therapy for rheumatic disease treatment. It can stabilize the condition of SLE patients and reduce the chances of patient relapse through its immunosuppressive function and antiinflammatory effects. This drug was absorbed completely and rapidly by oral administration, but has a prolonged half-life for elimination. The objective of this study was to evaluate the pharmacokinetic parameters and relative bioequivalence of a new generic (test) formulation with the branded (reference) formulation of HCQ in healthy Chinese male volunteers. This study was designed to acquire regulatory approval for the test formulation. Methods This study was conducted with a randomized, single-dose, two-period, and crossover design. The male subjects were randomly assigned to two groups at a 1:1 ratio to receive 0.2 g hydroxychloroquine sulfate tablets (0.1 g/piece) of the two formulations after a 3-month washout period then administered the alternate formulation. Study drugs were administered after overnight fasting (over 10 h). Plasma concentrations of hydroxychloroquine were measured by a validated LC-MS/MS method. The following pharmacokinetic properties were determined by a noncompartmental pharmacokinetic method: C _max, T _max, AUC_0–t , AUC_0–∝, and t _1/2. The bioequivalence between the test and reference products was assessed based on the following parameters: C _max, AUC0–60d, and AUC_0–∝ using the ANOVA method. If the 90% CI for AUC_0–t was within 80–125% and for C _max was within 70–143% of the statistical interval proposed by the SFDA, the two formulations were assumed bioequivalent. Concerning the main pharmacokinetic charateristics of hydroxychloroquine, a long half-life drug, the pharmacokinetic parameters of 0–72 h were determined according to the FDA. Furthermore, a comparison was made between the parameters at 0–60 days and 0–72 h to evaluate whether a truncated AUC method can be applied to estimate the relative bioavailability of HCQ. Tolerability was assessed by monitoring vital signs and laboratory tests and by questioning subjects about adverse events. Results The 90% CI of C _max for HCQ is 103.8–142.3%; the AUC0–60 is 100–114.2% and AUC_0–∝ 100–115.5%. Both met the criteria according to the SFDA’s guidelines for bioequivalence. The relative bioavailability was 109.5% (according to AUC_0–60d) and 110.7% (according to AUC_0–∝). No serious or unexpected adverse events were observed. Conclusions In this study, the pharmacokinetic studies and results were conducted so that the test and reference formulations of HCQ met the Chinese criteria for assuming bioequivalence. Both formulations were well tolerated in the population studies.

Astragalina alpestris is a traditional Chinese herbal medicine with anti-inflammatory, anti-immune, anti-tumor and other pharmacological effects. Calycosin and formononetin (FMN) are two natural compounds isolated from astragalus. It has been shown that calycosin and FMN are active anti-tumor ingredient. The aim of this current work was to study the therapeutic enhancement of temozolomide (TMZ) on gliomavia combining with calycosin and FMN. The effect of co-administration via hematoxylin-eosin staining (HE staining) was determined by measuring cell proliferation toxicity with the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide, Thiazolyl Blue Tetrazolium Bromide (MTT) assay and sequentially observing the cell morphology. To synchronously explore the effect of migration on C6, transwell assay and wound healing assay were performed. Apoptosis was measured by Annexin V/propidium iodide (PI) staining. Meanwhile, western blot was used to investigate proteins involved in the mechanisms for migration and apoptosis. Furthermore, HE staining and immunohistochemistry were also analyzed for curative effect in vivo. The efficacy of TMZ on glioma could be enhanced by combining with calycosin and FMN through inhibiting the proliferation and migration of glioma cells and promoting their apoptosis. Western blot assays indicated that expression of apoptotic proteins (Bcl-2 Associated XProtein (Bax), Cleaved Caspase-3, Cleaved Caspase-9) were up-regulated. Anti-apoptotic protein (B-cell lymphoma-2,Bcl-2) was down-regulated. The migratory proteins (Matrix metallopeptidase 2, 9, MMP-2, MMP-9) was downregulated. In vivo study, this kind of co-administration (calycosin, FMN, and TMZ) exhibited the marked therapeutic effect on glioma. This study has identified that calycosin and FMN can increase the treatment effect of TMZ in vitro and in vivo. These attractive features substantially broadened the application range of TMZ as a glioma treatment medicine.

Objectives: Glioblastoma is the most common malignant glioma of all brain tumours. It is difficult to treat because of its poor response to chemotherapy and radiotherapy and high recurrence rate after treatment. The aetiology of glioblastoma is a result of disorders of multiple factors. Depending on cell signal transduction, these glioblastoma‐associated factors lead to cell proliferation, differentiation and apoptosis. Therefore, investigation of the potential factors which involved in the development of glioblastoma could provide a new target for the treatment of glioblastoma.Materials and methods: We analysed the transcript expression of CLEC5A in glioblastoma by accessing The Cancer Genome Atlas (TCGA). qRT‐PCR was performed to detect the RNA expression of genes in cells and tissues, and Western blot was used to measure the protein levels (Cyclin D1, Bcl‐2, BAX, PCNA, MMP2, MMP9, Akt and Akt phosphorylation) in tissues and cells. Cell proliferation, migration, invasion, cycle and apoptosis were measured by CCK‐8, transwell and flow cytometry assays, respectively. Ki67 level and lung metastasis were determined by immunochemistry and H&E staining.Results: In this study, we found that CLEC5A was highly upregulated in glioblastoma compared to normal brain tissues, which had an opposite relation with the overall patient survival. Downregulation of CLEC5A could inhibit cell proliferation, migration and invasion via promoting apoptosis and G1 arrest. In contrast, overexpression of CLEC5A stimulated cell proliferation, migration and invasion. In addition, we found that CLEC5A level was positively correlated with Akt phosphorylation level. Akt inhibitor or agonist could reverse the modulation effects of CLEC5A in glioblastoma. Moreover, In vivo results suggested that inhibition of CLEC5A significantly reduced tumour size, weight, cell proliferation ability and lung metastasis via inhibition of phosphorylation Akt.Conclusion: Both in vitro and in vivo evidences supported that CLEC5A was involved in glioblastoma pathogenesis via regulation of PI3K/Akt pathway. Thus, CLEC5A might serve as a potential therapeutic target in the treatment of glioblastoma in the future.

Background. Cholesterol efflux and lipid raft redistribution contribute to attenuating temozolomide resistance of glioblastoma. Ginsenosides are demonstrated to modify cholesterol metabolism and lipid raft distribution, and the brain distribution and central nervous effects of whose isoforms Rb1, Rg1, Rg3, and CK have been identified. This study aimed to reveal the role of Rb1, Rg1, Rg3, and CK in the drug resistance of glioblastoma. Methods. The effects of ginsenosides on cholesterol metabolism in temozolomide-resistant U251 glioblastoma cells were evaluated by cholesterol content and efflux assay, confocal laser, qRT-PCR, and Western blot. The roles of cholesterol and ginsenosides in temozolomide resistance were studied by CCK-8, flow cytometry, and Western blot, and the mechanism of ginsenosides attenuating resistance was confirmed by inhibitors. Results. Cholesterol protected the survival of resistant U251 cells from temozolomide stress and upregulated multidrug resistance protein (MDR)1, which localizes in lipid rafts. Resistant cells tended to store cholesterol intracellularly, with limited cholesterol efflux and LXRα expression to maintain the distribution of lipid rafts. Ginsenosides Rb1, Rg1, Rg3, and CK reduced intracellular cholesterol and promoted cholesterol efflux in resistant cells, causing lipid rafts to accumulate in specific regions of the membrane. Rg1 and CK also upregulated LXRα expression and increased the cytotoxicity of temozolomide in the presence of cholesterol. We further found that cholesterol efflux induction, lipid raft redistribution, and temozolomide sensitization by Rg1 and CK were induced by stimulating LXRα. Conclusions. Ginsenosides Rg1 and CK controlled temozolomide resistance in glioblastoma cells by regulating cholesterol metabolism, which are potential synergists for temozolomide therapy.