Loss of PTPRS elicits potent metastatic capability and resistance to temozolomide in glioblastoma.

Glioblastoma (GBM) is the most aggressive brain tumor type with worse clinical outcome due to the hallmarks of strong invasiveness, high rate of recurrence, and therapeutic resistance to temozolomide (TMZ), the first-line drug for GBM, representing a major challenge for successful GBM therapeutics. Understanding the underlying mechanisms that drive GBM progression will shed novel insight into therapeutic strategies. Receptor-type tyrosine-protein phosphatase S (PTPRS) is a frequently mutated gene in human cancers, including GBM. Its role in GBM has not yet been clarified. Here, inactivating PTPRS mutation or deficiency was frequently found in GBM, and deficiency in PTPRS significantly induced defects in the G2M checkpoint and limited GBM cells proliferation, leading to potent resistance to TMZ treatment in vitro and in vivo. Surprisingly, loss of PTPRS triggered an unexpected mesenchymal phenotype that markedly enhances the migratory capabilities of GBM cells through upregulating numerous matrix metalloproteinases via MAPK-MEK-ERK signaling. Therefore, this work provides a therapeutic window for precisely excluding PTPRS-mutated patients who do not respond to TMZ.

ATAT1 deficiency enhances microglia/macrophage-mediated erythrophagocytosis and hematoma absorption following intracerebral hemorrhage.

MIcroglia/macrophage-mediated erythrophagocytosis plays a crucial role in hematoma clearance after intracerebral hemorrhage. Dynamic cytoskeletal changes accompany phagocytosis. However, whether and how these changes are associated with microglia/macrophage-mediated erythrophagocytosis remain unclear. In this study, we investigated the function of acetylated α-tubulin, a stabilized microtubule form, in microglia/macrophage erythrophagocytosis after intracerebral hemorrhage both in vitro and in vivo. We first assessed the function of acetylated α-tubulin in erythrophagocytosis using primary DiO GFP-labeled red blood cells co-cultured with the BV2 microglia or RAW264.7 macrophage cell lines. Acetylated α-tubulin expression was significantly decreased in BV2 and RAW264.7 cells during erythrophagocytosis. Moreover, silencing α-tubulin acetyltransferase 1 (ATAT1), a newly discovered α-tubulin acetyltransferase, decreased Ac-α-tub levels and enhanced the erythrophagocytosis by BV2 and RAW264.7 cells. Consistent with these findings, in ATAT1-/- mice, we observed increased ionized calcium binding adapter molecule 1 (Iba1) and Perls-positive microglia/macrophage phagocytes of red blood cells in peri-hematoma and reduced hematoma volume in mice with intracerebral hemorrhage. Additionally, knocking out ATAT1 alleviated neuronal apoptosis and pro-inflammatory cytokines and increased anti-inflammatory cytokines around the hematoma, ultimately improving neurological recovery of mice after intracerebral hemorrhage. These findings suggest that ATAT1 deficiency accelerates erythrophagocytosis by microglia/macrophages and hematoma absorption after intracerebral hemorrhage. These results provide novel insights into the mechanisms of hematoma clearance and suggest ATAT1 as a potential target for the treatment of intracerebral hemorrhage.

Potential of Depth-of-Interaction-Based Detection Time Correction in Cherenkov Emitter Crystals for TOF-PET.

Cherenkov light can improve the timing resolution of Positron Emission Tomography (PET) radiation detectors, thanks to its prompt emission. Coincidence time resolutions (CTR) of ~30 ps were recently reported when using 3.2 mm-thick Cherenkov emitters. However, sufficient detection efficiency requires thicker crystals, causing the timing resolution to be degraded by the optical propagation inside the crystal. We report on depth-of-interaction (DOI) correction to mitigate the time-jitter due to the photon time spread in Cherenkov-based radiation detectors. We simulated the Cherenkov and scintillation light generation and propagation in 3 × 3 mm2 lead fluoride, lutetium oxyorthosilicate, bismuth germanate, thallium chloride, and thallium bromide. Crystal thicknesses varied from 9 to 18 mm with a 3-mm step. A DOI-based time correction showed a 2-to-2.5-fold reduction of the photon time spread across all materials and thicknesses. Results showed that highly refractive crystals, though producing more Cherenkov photons, were limited by an experimentally obtained high-cutoff wavelength and refractive index, restricting the propagation and extraction of Cherenkov photons mainly emitted at shorter wavelengths. Correcting the detection time using DOI information shows a high potential to mitigate the photon time spread. These simulations highlight the complexity of Cherenkov-based detectors and the competing factors in improving timing resolution.

Interference with NTSR1 Expression Exerts an Anti-Invasion Effect via the Jun/miR-494/SOCS6 Axis of Glioblastoma Cells.

BACKGROUND/AIMS: Glioblastoma is the most common and aggressive brain tumor and carries a poor prognosis. Previously, we found that neurotensin receptor 1 (NTSR1) contributes to glioma progression, but the underlying mechanisms of NTSR1 in glioblastoma invasion remain to be clarified. The aim of this study was to investigate the molecular mechanisms of NTSR1 in glioblastoma invasion. METHODS: Cell migration and invasion were evaluated using wound-healing and transwell assays. Cell proliferation was detected using CCK-8. The expression of NTSR1, Jun, and suppressor of cytokine signaling 6 (SOCS6) was detected using western blotting. The expression of miR-494 was detected by Quantitative real-time PCR. Chromatin immunoprecipitation assay was performed to examine the interaction between Jun and miR-494 promoter. Dual-luciferase reporter assay and western blotting were performed to identify the direct regulation of SOCS6 by miR-494. An orthotopic xenograft mouse model was conducted to assess tumor growth and invasion. RESULTS: NTSR1 knockdown attenuated the invasion of glioblastoma cells. Jun was positively regulated by NTSR1, which promoted miR-494 expression through binding to miR-494 promoter. SOCS6 was confirmed as a direct target of miR-494, thus, NTSR1-induced miR-494 upregulation resulted in SOCS6 downregulation. Both miR-494 and SOCS6 were involved in the NTSR1-induced invasion of glioblastoma cells. In vivo, tumor invasion and growth were inhibited by NTSR1 knockdown, but were restored with miR-494 overexpression. CONCLUSION: NTSR1 knockdown inhibited glioblastoma invasion via the Jun/miR-494/SOCS6 axis.

Characterization of 7A7, an anti-mouse EGFR monoclonal antibody proposed to be the mouse equivalent of cetuximab.

The Epidermal Growth Factor Receptor (EGFR) is selectively expressed on the surface of numerous tumours, such as non-small cell lung, ovarian, colorectal and head and neck carcinomas. EGFR has therefore become a target for cancer therapy. Cetuximab is a chimeric human/mouse monoclonal antibody (mAb) that binds to EGFR, where it both inhibits signaling and induces cell death by antibody-dependent cell mediated cytotoxicity (ADCC). Cetuximab has been approved for clinical use in patients with head and neck squamous cell carcinoma (HNSCC) and colorectal cancer. However, only 15-20% patients benefit from this drug, thus new strategies to improve cetuximab efficiency are required. We aimed to develop a reliable and easy preclinical mouse model to evaluate the efficacy of EGFR-targeted antibodies and examine the immune mechanisms involved in tumour regression. We selected an anti-mouse EGFR mAb, 7A7, which has been reported to be "mouse cetuximab" and to exhibit similar properties to its human counterpart. Unfortunately, we were unable to reproduce previous results obtained with the 7A7 mAb. In our hands, 7A7 failed to recognize mouse EGFR, both in native and reducing conditions. Moreover, in vivo administration of 7A7 in an EGFR-expressing HPV38 tumour model did not have any impact on tumour regression or animal survival. We conclude that 7A7 does not recognize mouse EGFR and therefore cannot be used as the mouse equivalent of cetuximab use in humans. As a number of groups have spent effort and resources with similar issues we feel that publication is a responsible approach.

Expression levels of microRNA-199 and hypoxia-inducible factor-1 alpha in brain tissue of patients with intractable epilepsy.

OBJECTIVES: During the last decade, experimental evidence has demonstrated an important role of hypoxia, which leads to neuronal cell death and angiogenesis, in the mechanisms of seizure precipitation and recurrence. MicroRNA-199 targets hypoxia-inducible factor-1alpha (HIF-1α), which has recently been implicated in the pathophysiology of the hypoxic state and brain injury. However, little is known about the roles of MicroRNA-199 and HIF-1α in the human epileptogenic process. DESIGN AND METHODS: In this study, we investigated the expression of miR-199a-5p, miR-199b-5p and HIF-1α using real-time PCR, immunohistochemistry and western blots in the temporal neocortex of twenty four patients with intractable epilepsy and twelve control subjects. RESULTS: Compared with the control group, the expression of miR-199a-5p and miR-199b-5p was significantly lower in epileptic brain tissues (p < 0.05). The levels of HIF-1α mRNA and protein were highly up-regulated in epileptic brain tissues compared with those of control subjects (p < 0.05). CONCLUSION: These data suggest that the abnormal expression of miR-199 and HIF-1α in epileptic brain tissue may be involved in the pathophysiology of human epilepsy and that the expression of HIF-1α may be regulated by miR-199. These findings may provide new insights into the treatment of epilepsy.

Efficacy and safety of carmustine wafers in the treatment of glioblastoma multiforme: a systematic review.

The aim of this study was to a conduct a systematic review of carmustine wafers (Gliadel wafers) for the treatment of glioblastoma multiforme (GBM) to assess the survival benefit and safety of this therapy. The inclusion criteria were 1) prospective or retrospective clinical trial; 2) patients who had undergone resection for primary GBM or first recurrence of GBM with or without carmustine wafer implantation; 3) patients with malignant gliomas that included GBM; 4) outcomes including survival analysis of the GBM population. Six trials met the inclusion criteria; four were randomized, controlled trials and two were retrospective. The trials varied with regard to the type of patients and interventions. In three of the trials, patients with GBM who received carmustine wafers had significantly longer median survival than patients who did not receive wafers. Implantation of carmustine wafers did not significantly improve progression-free survival. Carmustine wafers did not increase adverse effects. This systematic review suggests that carmustine wafers have demonstrated promise as an effective and tolerable treatment in comparison to other treatment strategies in patients with GBM.

Synthesis and anti-inflammatory evaluation of novel mono-carbonyl analogues of curcumin in LPS-stimulated RAW 264.7 macrophages.

Curcumin is a multifunctional natural product with regulatory effects on inflammation. However, a major limitation for the application of curcumin is its poor bioavailability. We previously demonstrated that the mono-carbonyl analogues of curcumin possessed improved pharmacokinetic profiles. In this study, 33 novel mono-carbonyl analogues of curcumin were synthesized and their inhibition against TNF-α and IL-6 release was evaluated in LPS-stimulated RAW 264.7 macrophages. Based on the screening data, quantitative structure-activity relationship was conducted, indicating that electron-withdrawing groups in benzene ring are favourable to anti-inflammatory activities of B-class compounds. Furthermore, compounds AN1 and B82 demonstrated anti-inflammatory abilities in a dose-dependent manner. These raise the possibility that these compounds might serve as potential agents for the treatment of inflammatory diseases.