The effect of hypoxia on photodynamic therapy with 5-aminolevulinic acid in malignant gliomas

BackgroundGlioblastoma (GBM) is a high-grade, poor prognosis tumor that is resistant to standard treatment. The presence of a small number of glioma stem cells (GSCs) surviving in the harsh microenvironment is responsible for their refractoriness. This study aimed to investigate the effect of a hypoxic environment on the sensitivity of GSCs to photodynamic therapy with 5-aminolevulinic acid (ALA-PDT).Materials and methodsSix human GSC lines, Mesenchymal types HGG13, HGG30, HGG1123, and Proneural types HGG146, HGG157, HGG528, were divided into two groups: normoxia (O₂ 21%)-cultured cells (Normoxia-GSCs), and hypoxia (O₂ 5%)-cultured cells (Hypoxia-GSCs). To compare the effects of different oxygen partial pressures on photoporphyrin Ⅸ (PpⅨ) biosynthetic activity, PpⅨ biosynthetic enzyme and transporter expression levels were examined by qRT-PCR; the intracellular PpⅨ concentration was determined using flow cytometry. Additionally, the sensitivity of these two groups of cells to ALA-PDT was evaluated in vitro.ResultsHypoxia-GSCs showed higher mRNA levels of FECH (ferrochelatase), which is required for iron synthesis to convert PpⅨ to heme, compared with Normoxia-GSCs. Flow cytometry revealed that the accumulation of PpⅨ in Hypoxia-GSCs reduced upon incubation with ALA. However, Hypoxia-GSCs showed less reduction in sensitivity to ALA-PDT than Normoxia-GSCs.ConclusionHypoxia-GSCs had lower intracellular PpⅨ accumulation than Normoxia-GSCs due to increased gene expression of FECH, and that their sensitivity to ALA-PDT was reduced less, despite accumulating lower concentrations of PpⅨ. ALA-PDT is a potentially effective therapy for hypoxia-tolerant GSCs that exist in hypoxia at 5% oxygen concentration.     

miR-147对胶质瘤U87细胞增殖、凋亡和侵袭的影响

目的:比较胶质瘤患者胶质瘤组织和瘤旁组织中miR-147表达水平的差异性，进一步分析miR-147与胶质瘤细胞生物学活性的相关性。方法:通过实时荧光定量PCR检测65例胶质瘤患者瘤组织和瘤旁组织中miR-147的表达水平；采用Lipofectamine 2000转染法转染胶质瘤细胞，分为miR-147 mimics组和NC组，检测两组转染效率；进一步通过CCK-8实验、流式细胞实验和Transwell实验比较两组细胞生物活性。结果:胶质瘤组织中miR-147表达水平显著低于瘤旁组织；与NC组比较，miR-147 mimics组细胞不论是增殖能力还是侵袭能力都明显降低，但是，miR-147 mimics组的细胞凋亡率升高。结论:胶质瘤组织中存在miR-147低表达的现象。miR-147在胶质瘤细胞中表达升高能够抑制细胞的增殖能力、降低其侵袭能力，并促使更多的细胞发生晚期凋亡。miR-147可能在胶质瘤中扮演着抑癌基因的重要角色。     

丙戊酸钠通过EGFR下调CD44表达抑制胶质瘤细胞生长

目的:探讨丙戊酸钠通过抑制A172胶质瘤细胞表皮生长因子受体（epidermal growth factor receptor，EGFR）的活化，下调CD44表达，进而调节细胞生长的机制。方法:实时荧光定量PCR和Western blot检测A172胶质瘤细胞中CD44以及siRNA下调CD44表达的情况，MTT检测CD44和丙戊酸钠对细胞生长的影响，Western blot检测丙戊酸钠对细胞中p-EGFR、EGFR和CD44表达影响。结果:丙戊酸钠抑制A172胶质瘤细胞生长，并具有浓度依赖性。A172胶质瘤细胞表达CD44，siRNA下调CD44表达后，细胞生长较正常组显著减缓。活化EGFR促进A172胶质瘤CD44蛋白表达，而EGFR的抑制剂Lapatinib可显著抑制上述效应。丙戊酸钠抑制EGFR磷酸化，下调CD44蛋白表达。结论:丙戊酸钠抑制A172胶质瘤细胞的生长。抑制A172胶质瘤细胞中EGFR的活化，下调CD44的表达，是丙戊酸钠抑制胶质瘤细胞生长的其中一个机制。     

Prognostic impact of distinct genetic entities in pediatric diffuse glioma WHO-grade II—Report from the German/Swiss SIOP-LGG 2004 cohort

Reports on pediatric low-grade diffuse glioma WHO-grade II (DG2) suggest an impaired survival rate, but lack conclusive results for genetically defined DG2-entities. We analyzed the natural history, treatment and prognosis of DG2 and investigated which genetically defined sub-entities proved unfavorable for survival. Within the prospectively registered, population-based German/Swiss SIOP-LGG 2004 cohort 100 patients (age 0.8-17.8 years, 4% neurofibromatosis [NF1]) were diagnosed with a DG2. Following biopsy (41%) or variable extent of resection (59%), 65 patients received no adjuvant treatment. Radiologic progression or severe neurologic symptoms prompted chemotherapy (n = 18) or radiotherapy (n = 17). Multiple lines of salvage treatment were necessary for 19/35 patients. Five years event-free survival dropped to 0.44, while 5 years overall survival was 0.90 (median observation time 8.3 years). Extensive genetic profiling of 65/100 DG2 identified Histone3-K27M-mutation in 4, IDH1-mutation in 11, BRAF-V600-mutation in 12, KIAA1549-BRAF-fusions in 6 patients, while the remaining 32 tumor tissues did not show alterations of these genes. Progression to malignant glioma occurred in 12 cases of all genetically defined subgroups within a range of 0.5 to 10.8 years, except for tumors carrying KIAA1549-BRAF-fusions. Histone3-K27M-mutant tumors proved uniformly fatal within 0.6 to 2.4 years. The current LGG treatment strategy seems appropriate for all DG2-entities, with the exemption of Histone3-K27M-mutant tumors that require a HGG-related treatment strategy. Our data confirm the importance to genetically define pediatric low-grade diffuse gliomas for proper treatment decisions and risk assessment.     

A novel lncRNA-LINC01116 regulates tumorigenesis of glioma by targeting VEGFA

Brain glioma is the most common malignant tumor of the central nervous system, and one of the leading causes of death in patients with intracranial tumors. The clinical outcome of glioma is usually poor due to abundant vascularity, fast growth and susceptibility of invasion to normal brain tissues. Our microarray study showed that lncRNA-LINC01116 was significantly upregulated in glioma tissues and played an important role in cell proliferation, cycle, migration, invasion and angiogenesis. In addition, vascular endothelial growth factor (VEGFA) may be the major target genes in the downstream of lncRNA-LINC01116. Dual luciferase assay showed that LINC01116 and VEGFA both contained a miR-31-5p binding site, and LINC01116 could regulate the expression of VEGFA through competitive absorption of miR-31-5p. RNA immunoprecipitation indicated that LINC01116 and VEGFA were present in the miR-31-5p-RISC complex, and biotinylated miR-31-5p pull-down assay suggested that there was a competitive relationship between LINC01116 and VEGFA to bind with miR-31-5p. Collectively, our study has identified a novel lncRNA-LINC01116 and clarified the role and mechanism of LINC01116 in the tumorigenesis of glioma. LINC01116 may prove to be a potential target for the clinical diagnosis and treatment of glioma.     

Biofunctionalization of magnetite nanoparticles with stevioside: effect on the size and thermal behaviour for use in hyperthermia applications

Controlling the magnetic properties of a nanoparticle efficiently via its particle size to achieve optimized heat under alternating magnetic field is the central point for magnetic hyperthermia-mediated cancer therapy (MHCT). Here, we have shown the successful use of stevioside (a natural plant-based glycoside) as a promising biosurfactant to control the magnetic properties of Fe₃O₄ nanoparticles by controlling the particle size. The biocompatibility and cellular uptake efficiency by rat C6 glioma cells and calorimetric magnetic hyperthermia profile of the nanoparticles were further examined. Our finding suggests superior properties of stevioside-coated magnetite nanoparticles in comparison to polysorbate-80 and oleic acid coated nanomagnets as far as particle size reduction, biocompatibility, hyperthermic effect, and cellular uptake by the glioblastoma cancer cells are concerned. The stevioside-coated nanomagnets exhibiting the maximum temperature rise were further investigated as heating agents in in vitro magnetic hyperthermia experiments (405?kHz, 168?Oe), showing their efficacy to induce cell death of rat C6 glioma cells after 30?min at a target temperature T?=?43?°C.     

Circular RNA hsa_circ_0005114-miR-142-3p/miR-590-5p-adenomatous polyposis coli protein axis as a potential target for treatment of glioma

Glioma is the most common type of brain tumor and is associated with a high mortality rate. Despite recent advances in treatment options, the overall prognosis in patients with glioma remains poor. Studies have suggested that circular (circ)RNAs serve important roles in the development and progression of glioma and may have potential as therapeutic targets. However, the expression profiles of circRNAs and their functions in glioma have rarely been studied. The present study aimed to screen differentially expressed circRNAs (DECs) between glioma and normal brain tissues using sequencing data collected from the Gene Expression Omnibus database ({"type":"entrez-geo","attrs":{"text":"GSE86202","term_id":"86202"}}GSE86202 and {"type":"entrez-geo","attrs":{"text":"GSE92322","term_id":"92322"}}GSE92322 datasets) and explain their mechanisms based on the competing endogenous (ce)RNA regulatory hypothesis. In total, 424 commonly downregulated DECs (with the Gene_symbol annotated in the circBase database) in these two datasets were identified. Using the CircInteractome and Starbase databases, 18 micro (mi)RNAs (miRs) were predicted to interact with DECs, while 22 glioma-related genes obtained from the Comparative Toxicogenomics Database were predicted to be regulated by 15 miRNAs via the miRwalk 2.0 database. A ceRNA network was established based on 115 DECs, 15 miRNAs and 22 mRNAs. LinkedOmics online analysis using The Cancer Genome Atlas (TCGA) data showed that hsa-miR-142-3p/hsa-miR-590-5p and their target gene adenomatous polyposis coli protein (APC) were all significantly associated with overall survival rate and their prognosis trend was opposite, revealing that high expression levels of hsa-miR-142-3p/hsa-miR-590-5 were associated with a poor overall survival rate, while high APC expression with a good overall survival rate. UALCAN analysis using TCGA data of glioblastoma multiforme and the {"type":"entrez-geo","attrs":{"text":"GSE25632","term_id":"25632"}}GSE25632 and {"type":"entrez-geo","attrs":{"text":"GSE103229","term_id":"103229"}}GSE103229 microarray datasets showed that hsa-miR-142-3p/hsa-miR-590-5p was upregulated and APC was downregulated. Thus, hsa-miR-142-3p/hsa-miR-590-5p-APC-related circ/ceRNA axes may be important in glioma, and hsa_circ_0005114 interacted with both of these miRNAs. Functional analysis showed that hsa_circ_0005114 was involved in insulin secretion, while APC was associated with the Wnt signaling pathway. In conclusion, hsa_circ_0005114-miR-142-3p/miR-590-5p-APC ceRNA axes may be potential targets for the treatment of glioma.     

High-dose salvage re-irradiation in recurrent/progressive adult diffuse gliomas: development of a novel prognostic scoring system

PurposeOver the past two decades, high-dose salvage re-irradiation (re-RT) has been used increasingly in the multimodality management of adults with recurrent/progressive diffuse glioma. Several factors that determine outcomes following re-RT have been incorporated into prognostic models to guide patient selection. We aimed to develop a novel four-tiered prognostic model incorporating relevant molecular markers from our single-institutional cohort of patients treated with high-dose salvage re-RT for recurrent/progressive diffuse glioma.Material and methodsVarious patient, disease, and treatment-related factors impacting upon survival following salvage re-RT were identified through univariate analysis. Each of these prognostic factors was further subdivided and assigned scores of 0 (low-risk), 1 (intermediate-risk), or 2 (high-risk). Scores from individual prognostic factors were added to derive the cumulative score (ranging from 0 to 16), with increasing scores indicating worsening prognosis.ResultsA total of 111 adults with recurrent/progressive diffuse glioma treated with salvage high-dose re-RT were included. We could assign patients into four prognostic subgroups (A = 15 patients, score 0–3); (B = 50 patients, score 4–7); (C = 33 patients, score 8–10); and (D = 13 patients, score 11–16) with completely non-overlapping survival curves suggesting the good discriminatory ability. Post-re-RT survival was significantly higher in Group A compared to groups B, C, and D, respectively (stratified log-rank p-value <0.0001).ConclusionThere exists a lack of universally acceptable ‘standard-of-care’ salvage therapy for recurrent/progressive diffuse glioma. A novel four-tiered prognostic scoring system incorporating traditional factors as well as relevant molecular markers is proposed for selecting patients appropriately for high-dose salvage re-RT that warrants validation in a non-overlapping cohort.     

A druggable addiction to de novo pyrimidine biosynthesis in diffuse midline glioma

1. Download : Download high-res image (148KB)
2. Download : Download full-size image