CRISPR-Cas9 library screening combined with an exosome-targeted delivery system addresses tumorigenesis/TMZ resistance in the mesenchymal subtype of glioblastoma.

Rationale: The large-scale genomic analysis classifies glioblastoma (GBM) into three major subtypes, including classical (CL), proneural (PN), and mesenchymal (MES) subtypes. Each of these subtypes exhibits a varying degree of sensitivity to the temozolomide (TMZ) treatment, while the prognosis corresponds to the molecular and genetic characteristics of the tumor cell type. Tumors with MES features are predominantly characterized by the NF1 deletion/alteration, leading to sustained activation of the RAS and PI3K-AKT signaling pathways in GBM and tend to acquire drug resistance, resulting in the worst prognosis compared to other subtypes (PN and CL). Here, we used the CRISPR/Cas9 library screening technique to detect TMZ-related gene targets that might play roles in acquiring drug resistance, using overexpressed KRAS-G12C mutant GBM cell lines. The study identified a key therapeutic strategy to address the chemoresistance against the MES subtype of GBM. Methods: The CRISPR-Cas9 library screening was used to discover genes associated with TMZ resistance in the U87-KRAS (U87-MG which is overexpressed KRAS-G12C mutant) cells. The patient-derived GBM primary cell line TBD0220 was used for experimental validations in vivo and in vitro. Chromatin isolation by RNA purification (ChIRP) and chromatin immunoprecipitation (ChIP) assays were used to elucidate the silencing mechanism of tumor suppressor genes in the MES-GBM subtype. The small-molecule inhibitor EPIC-0412 was obtained through high-throughput screening. Transmission electron microscopy (TEM) was used to characterize the exosomes (Exos) secreted by GBM cells after TMZ treatment. Blood-derived Exos-based targeted delivery of siRNA, TMZ, and EPIC-0412 was optimized to tailor personalized therapy in vivo. Results: Using the genome-wide CRISPR-Cas9 library screening, we found that the ERBIN gene could be epigenetically regulated in the U87-KRAS cells. ERBIN overexpression inhibited the RAS signaling and downstream proliferation and invasion effects of GBM tumor cells. EPIC-0412 treatment inhibited tumor proliferation and EMT progression by upregulating the ERBIN expression both in vitro and in vivo. Genome-wide CRISPR-Cas9 screening also identified RASGRP1(Ras guanine nucleotide-releasing protein 1) and VPS28(Vacuolar protein sorting-associated protein 28) genes as synthetically lethal in response to TMZ treatment in the U87-KRAS cells. We found that RASGRP1 activated the RAS-mediated DDR pathway by promoting the RAS-GTP transformation. VPS28 promoted the Exos secretion and decreased intracellular TMZ concentration in GBM cells. The targeted Exos delivery system encapsulating drugs and siRNAs together showed a powerful therapeutic effect against GBM in vivo. Conclusions: We demonstrate a new mechanism by which ERBIN is epigenetically silenced by the RAS signaling in the MES subtype of GBM. Restoration of the ERBIN expression with EPIC-0412 significantly inhibits the RAS signaling downstream. RASGRP1 and VPS28 genes are associated with the promotion of TMZ resistance through RAS-GDP to RAS-GTP transformation and TMZ efflux, as well. A quadruple combination therapy based on a targeted Exos delivery system demonstrated significantly reduced tumor burden in vivo. Therefore, our study provides new insights and therapeutic approaches for regulating tumor progression and TMZ resistance in the MES-GBM subtype.

EPIC-1042 as a potent PTRF/Cavin1-caveolin-1 interaction inhibitor to induce PARP1 autophagic degradation and suppress temozolomide efflux for glioblastoma.

BACKGROUND: Temozolomide (TMZ) treatment efficacy in glioblastoma is determined by various mechanisms such as TMZ efflux, autophagy, base excision repair (BER) pathway, and the level of O6-methylguanine-DNA methyltransferase (MGMT). Here, we reported a novel small-molecular inhibitor (SMI) EPIC-1042 (C20H28N6) with the potential to decrease TMZ efflux and promote PARP1 degradation via autolysosomes in the early stage. METHODS: EPIC-1042 was obtained from receptor-based virtual screening. Co-immunoprecipitation and pull-down assays were applied to verify the blocking effect of EPIC-1042. Western blotting, co-immunoprecipitation, and immunofluorescence were used to elucidate the underlying mechanisms of EPIC-1042. In vivo experiments were performed to verify the efficacy of EPIC-1042 in sensitizing glioblastoma cells to TMZ. RESULTS: EPIC-1042 physically interrupted the interaction of PTRF/Cavin1 and caveolin-1, leading to reduced secretion of small extracellular vesicles (sEVs) to decrease TMZ efflux. It also induced PARP1 autophagic degradation via increased p62 expression that more p62 bound to PARP1 and specially promoted PARP1 translocation into autolysosomes for degradation in the early stage. Moreover, EPIC-1042 inhibited autophagy flux at last. The application of EPIC-1042 enhanced TMZ efficacy in glioblastoma in vivo. CONCLUSION: EPIC-1042 reinforced the effect of TMZ by preventing TMZ efflux, inducing PARP1 degradation via autolysosomes to perturb the BER pathway and recruitment of MGMT, and inhibiting autophagy flux in the later stage. Therefore, this study provided a novel therapeutic strategy using the combination of TMZ with EPIC-1042 for glioblastoma treatment.

Clinical presentation and magnetic resonance imaging characteristics of lymphocytic hypophysitis: a systematic review with meta-analysis.

Introduction: This meta-analysis was performed to analyze the clinical presentation, magnetic resonance imaging (MRI) characteristics, and the management of lymphocytic hypophysitis (LYH). Material and methods: Four different databases were searched from January 2010 to December 2020, two researchers independently conducted literature screening, data extraction, and quality evaluation. We used a random effects meta-analysis to calculate summary relative risks with 95% CI. Results: This meta-analysis showed that the percentage of women among LYH patients was 78%. LYH was associated with pregnancy in 15% of female patients, with headache (49%) and symptoms of central diabetes insipidus (CDI) (45%) being the most frequent presentation. In 24% of LYH patients, there was an association with another autoimmune disease. The incidence of secondary hypogonadism, secondary hypoadrenalism, secondary hypothyroidism, and growth hormone deficit was 54%, 49%, 43%, and 22%, respectively. Pituitary contrast enhancement (63%), symmetrical pituitary enlargement (60%), thickening of the pituitary stalk (58%), sella mass or suprasellar extension (58%), and loss of posterior pituitary hyperintensity (50%) were typical MRI findings. Regarding LYH treatment, the percentage of patients who had observation or hormone replacement, steroid therapy, and surgery was 43%, 36%, and 34%, respectively. Conclusions: It is of great significance to fully understand the clinical characteristics of lymphocytic hypophysitis, reduce missed diagnosis and misdiagnosis, avoid unnecessary surgery and maintain normal pituitary function.

Effect of Sodium Selenite on the Metabolite Profile of Epichloë sp. Mycelia from Festuca sinensis in Solid Culture.

Selenium (Se) is an essential micronutrient with many beneficial effects for humans and other living organisms. Numerous microorganisms in culture systems enrich and convert inorganic selenium to organic selenium. In this study, Epichloë sp. from Festuca sinensis was exposed to increasing Na2SeO3 concentrations (0, 0.1, 0.2, 0.3, and 0.4 mmol/L) in Petri dishes with potato dextrose agar (PDA) for 8 weeks. Epichloë sp. mycelia were immediately collected after mycelial diameters were measured at 4, 5, 6, 7, and 8 weeks of cultivation, respectively. Gas chromatography-mass spectrometer (GC-MS) analysis was performed on different groups of Epichloë sp. mycelia. Different changes were observed as Epichloë sp. was exposed to different selenite conditions and cultivation time. The colony diameter of Epichloë sp. decreased in response to increased selenite concentrations, whereas the inhibitory effects diminished over time. Seventy-two of the 203 identified metabolites did not differ significantly across selenite treatments within the same time point, while 82 compounds did not differ significantly between multiple time points of the same Se concentration. However, the relative levels of 122 metabolites increased the most under selenite conditions. Specifically, between the 4th and 8th weeks, there were increases in 2-keto-isovaleric acid, uridine, and maltose in selenite treatments compared to controls. Selenium increased glutathione levels and exhibited antioxidant properties in weeks 4, 5, and 7. Additionally, we observed that different doses of selenite could promote the production of carbohydrates such as isomaltose, cellobiose, and sucrose; fatty acids such as palmitoleic acid, palmitic acid, and stearic acid; and amino acids such as lysine and tyrosine in Epichloë sp. mycelia. Therefore, Epichloë sp. exposed to selenite stress may benefit from increased levels of some metabolite compounds.

Meta-analysis on the effect of pituitary adenoma resection on pituitary function.

OBJECTIVE: A meta-analysis was conducted on the effect of pituitary adenoma resection on pituitary function. METHODS: The Cochrane Library, Ovid, PubMed, the Excerpta Medica Database (EMBASE), and the Chinese Biomedical Literature Databases (CBM) were searched to find trials about the evaluation of pituitary target glands before and after pituitary adenoma resection. The databases were searched from the earliest available trials until the end of September 2019. Based on the inclusion and exclusion criteria, two researchers independently selected literature, extracted data, and evaluated the quality of the studies, and then used Revman 5.2 software to conduct a meta-analysis. RESULTS: Eleven clinical trials were included, with a total of 3,237 subjects. Meta-analysis showed that the number of patients with hypofunction of the thyroid and gonadal axes substantially decreased after pituitary tumour resection, and that the difference was statistically significant: odds ratio (OR) = 1.72 [95% confidence interval (CI), 1.18-2.52; P = 0.005] and OR = 2.06 (95% CI, 1.42-3.00; P = 0.0002). The number of patients with a poor total suprarenal gland axis after pituitary tumour resection did not change significantly compared to the number found before the operation; the difference was not statistically significant: OR = 1.04 (95% CI, 0.72-1.48; P = 0.85). However, the number of patients who had adrenal axis dysfunction both before and after the operation was significantly reduced, and the difference was statistically significant: OR = 1.46 (95% CI, 1.21-1.78; P = 0.0001). CONCLUSION: The function of the thyroid and gonadal axes of pituitary gland tumour patients can be improved, to some extent, after pituitary tumour resection. Patients with pituitary tumours who have hypofunction of the adrenal axis can recover effectively after tumour resection.