骨肉腫細胞の生存と増殖はミトコンドリア局在BIG3-PHB2複合体形成に依存する

Previous studies reported the critical role of the brefeldin A–inhibited guanine nucleotide exchange protein 3–prohibitin 2 (BIG3-PHB2) complex in modulating estrogen signaling activation in breast cancer cells, yet its pathophysiological roles in osteosarcoma (OS) cells remain elusive. Here, we report a novel function of BIG3-PHB2 in OS malignancy. BIG3-PHB2 complexes were localized mainly in mitochondria in OS cells, unlike in estrogen-dependent breast cancer cells. Depletion of endogenous BIG3 expression by small interfering RNA (siRNA) treatment led to significant inhibition of OS cell growth. Disruption of BIG3-PHB2 complex formation by treatment with specific peptide inhibitor also resulted in significant dose-dependent suppression of OS cell growth, migration, and invasion resulting from G2/M-phase arrest and in PARP cleavage, ultimately leading to PARP-1/apoptosis-inducing factor (AIF) pathway activation–dependent apoptosis in OS cells. Subsequent proteomic and bioinformatic pathway analyses revealed that disruption of the BIG3-PHB2 complex might lead to downregulation of inner mitochondrial membrane protein complex activity. Our findings indicate that the mitochondrial BIG3-PHB2 complex might regulate PARP-1/AIF pathway-dependent apoptosis during OS cell proliferation and progression and that disruption of this complex may be a promising therapeutic strategy for OS

Neural Sources of Vagus Nerve Stimulation–Induced Slow Cortical Potentials

[Objectives] This study investigated neuronal sources of slow cortical potentials (SCPs) evoked during vagus nerve stimulation (VNS) in patients with epilepsy who underwent routine electroencephalography (EEG) after implantation of the device. [Materials and Methods] We analyzed routine clinical EEG from 24 patients. There were 5 to 26 trains of VNS during EEG. To extract SCPs from the EEG, a high-frequency filter of 0.2 Hz was applied. These EEG epochs were averaged and used for source analyses. The averaged waveforms for each patient and their grand average were subjected to multidipole analysis. Patients with at least 50% seizure frequency reduction were considered responders. Findings from EEG analysis dipole were compared with VNS responses. [Results] VNS-induced focal SCPs whose dipoles were estimated to be located in several cortical areas including the medial prefrontal cortex, postcentral gyrus, and insula, with a significantly higher frequency in patients with a good VNS response than in those with a poor response. [Conclusions] This study suggested that some VNS-induced SCPs originating from the so-called vagus afferent network are related to the suppression of epileptic seizures

Critical roles of DDX31-mutp53-EGFR axis in MIBC progression

The p53 and EGFR pathways are frequently altered in bladder cancers, yet their contributions to its progression remain elusive. Here we report that DEAD box polypeptide 31 (DDX31) plays a critical role in the multistep progression of muscle invasive bladder cancer (MIBC) through its sequential interactions with mutant p53 (mutp53) and EGFR. In early MIBC cells, nuclear DDX31 bound mutp53/SP1 and enhanced mutp53 transcriptional activation, leading to migration and invasion of MIBC. Cytoplasmic DDX31 also bound EGFR and phospho-nucleolin (p-NCL) in advanced MIBC, leading to EGFR-Akt signaling activation. High expression of both cytoplasmic DDX31 and p53 proteins correlated with poor prognosis in patients with MIBC, and blocking the DDX31-NCL interaction resulted in downregulation of EGFR-Akt signaling, eliciting an in vivo anti-tumor effect against bladder cancer. These findings reveal that DDX31 cooperates with mutp53 and EGFR to promote progression of MIBC, and inhibition of DDX31-NCL formation may lead to potential treatment strategies for advanced MIBC

The antitumor activity of xanthohumol

Xanthohumol (XN), a simple prenylated chalcone, can be isolated from hops and has the potential to be a cancer chemopreventive agent against several human tumor cell lines. We previously identified valosin-containing protein (VCP) as a target of XN; VCP can also play crucial roles in cancer progression and prognosis. Therefore, we investigated the molecular mechanisms governing the contribution of VCP to the antitumor activity of XN. Several human tumor cell lines were treated with XN to investigate which human tumor cell lines are sensitive to XN. Several cell lines exhibited high sensitivity to XN both in vitro and in vivo. shRNA screening and bioinformatics analysis identified that the inhibition of the adenylate cyclase (AC) pathway synergistically facilitated apoptosis induced by VCP inhibition. These results suggest that there is crosstalk between the AC pathway and VCP function, and targeting both VCP and the AC pathway is a potential chemotherapeutic strategy for a subset of tumor cells

トリプル ネガティブ ニュウガン ニオケル プロテアソーム カンレン インシ PAG1 ニヨル シンキ ゾウショク キコウ ノ カイメイ

Triple negative breast cancer （TNBC） is considered to be one of the most aggressive subtypes of all breast cancers. To identify novel potential therapeutic targets and clarify pathophysiological features for TNBC, we conducted Meta-gene profiling analysis based on gene-expression profiling of TNBC cases purified by lasermicrobeam microdissection, and found that proteasome-associated genes （PAGs） were commonly upregulated in various pathways including cell cycle regulation in TNBC. Depletion of PAGs with RNAi caused the upregulation of p27 and p21 proteins in MDA-MB-231 and HCC1937 cells, respectively, resulting in growth inhibition. Interestingly, immunocytochmical staining revealed that PAG1 was observed in the nucleoli and/or cytoplasm （n-PAG1 and c-PAG1） in TNBC cell line and clinical specimens. Immunohistochemical staining of 100 TNBCs showed that high level of n-PAG1 was significantly associated with poor disease free and overall survival of TNBC patients. These results indicate that n-PAG1 plays a critical role in nucleus during cell cycle progression and might be a novel prognostic indicator or an attractive molecular target of TNBC

A-kinase anchoring protein BIG3 coordinates oestrogen signalling in breast cancer cells

Approximately 70% of breast cancer cells express oestrogen receptor alpha (ERα). Previous studies have shown that the Brefeldin A-inhibited guanine nucleotide-exchange protein 3–prohibitin 2 (BIG3-PHB2) complex has a crucial role in these cells. However, it remains unclear how BIG3 regulates the suppressive activity of PHB2. Here we demonstrate that BIG3 functions as an A-kinase anchoring protein that binds protein kinase A (PKA) and the α isoform of the catalytic subunit of protein phosphatase 1 (PP1Cα), thereby dephosphorylating and inactivating PHB2. E2-induced PKA-mediated phosphorylation of BIG3-S305 and -S1208 serves to enhance PP1Cα activity, resulting in E2/ERα signalling activation via PHB2 inactivation due to PHB2-S39 dephosphorylation. Furthermore, an analysis of independent cohorts of ERα-positive breast cancers patients reveal that both BIG3 overexpression and PHB2-S39 dephosphorylation are strongly associated with poor prognosis. This is the first demonstration of the mechanism of E2/ERα signalling activation via the BIG3–PKA–PP1Cα tri-complex in breast cancer cells

Peroxisome proliferator-activated receptor activity is involved in the osteoblastic differentiation regulated by bone morphogenetic proteins and tumor necrosis factor-α.

Recent studies have suggested possible adverse effects of thiazolidinediones on bone metabolism. However, the detailed mechanism by which the activity of PPAR affects bone formation has not been elucidated. Impaired osteoblastic function due to cytokines is critical for the progression of inflammatory bone diseases. In the present study, we investigated the cellular mechanism by which PPAR actions interact with osteoblast differentiation regulated by BMP and TNF-alpha using mouse myoblastic C2C12 cells. BMP-2 and -4 potently induced the expression of various bone differentiation markers including Runx2, osteocalcin, type-1 collagen and alkaline phosphatase (ALP) in C2C12 cells. When administered in combination with a PPAR alpha agonist (fenofibric acid) but not with a PPAR gamma agonist (pioglitazone), BMP-4 enhanced osteoblast differentiation through the activity of PPAR alpha. The osteoblastic changes induced by BMP-4 were readily suppressed by treatment with TNF-alpha. Interestingly, the activities of PPAR alpha and PPAR gamma agonists reversed the suppression by TNF-alpha of osteoblast differentiation induced by BMP-4. Furthermore, TNF-alpha-induced phosphorylation of MAPKs, NF kappa B, I kappa B and Stat pathways was inhibited in the presence of PPAR alpha and PPAR gamma agonists with reducing TNF-alpha receptor expression. In view of the finding that inhibition of SAPK/JNK. Stat and NF kappa B pathways reversed the TNF-alpha suppression of osteoblast differentiation, we conclude that these cascades are functionally involved in the actions of PPARs that antagonize TNF-alpha-induced suppression of osteoblast differentiation. It was further discovered that the PPAR alpha agonist enhanced BMP-4-induced Smad1/5/8 signaling through downregulation of inhibitory Smad6/7 expression, whereas the PPAR gamma agonist impaired this activity by suppressing BMPRII expression. On the other hand, BMPs increased the expression levels of PPAR alpha and PPAR gamma in the process of osteoblast differentiation. Thus, PPAR alpha actions promote BMP-induced osteoblast differentiation, while both activities of PPAR alpha and PPAR gamma suppress TNF-alpha actions. Collectively, our present data establishes that PPAR activities are functionally involved in modulating the interaction between the BMP system and TNF-alpha receptor signaling that is crucial for bone metabolism

Application of MRI Post-processing in Presurgical Evaluation of Non-lesional Cingulate Epilepsy

Background and Purpose: Surgical management of patients with cingulate epilepsy (CE) is highly challenging, especially when the MRI is non-lesional. We aimed to use a voxel-based MRI post-processing technique, implemented in a morphometric analysis program (MAP), to facilitate detection of subtle epileptogenic lesions in CE, thereby improving surgical evaluation of patients with CE with non-lesional MRI by visual inspection.Methods: Included in this retrospective study were 9 patients with CE (6 with negative 3T MRI and 3 with subtly lesional 3T MRI) who underwent surgery and became seizure-free or had marked seizure improvement with at least 1-year follow-up. MRI post-processing was applied to pre-surgical T1-weighted volumetric sequence using MAP. The MAP finding was then coregistered and compared with other non-invasive imaging tests (FDG-PET, SPECT and MEG), intracranial EEG ictal onset, surgery location and histopathology.Results: Single MAP+ abnormalities were found in 6 patients, including 3 patients with negative MRI, and 3 patients with subtly lesional MRI. Out of these 6 MAP+ patients, 4 patients became seizure-free after complete resection of the MAP+ abnormalities; 2 patients didn't become seizure-free following laser ablation that only partially overlapped with the MAP+ abnormalities. All MAP+ foci were concordant with intracranial EEG ictal onset (when performed). The localization value of FDG-PET, SPECT and MEG was limited in this cohort. FCD was identified in all patients' surgical pathology except for two cases of laser ablation with no tissue available.Conclusion: MAP provided helpful information for identifying subtle epileptogenic abnormalities in patients with non-lesional cingulate epilepsy. MRI postprocessing should be considered to add to the presurgical evaluation test battery of non-lesional cingulate epilepsy

Gradient magnetic-oscillation topography depicts high-frequency oscillations on the brain surface related to the epileptic focus in intractable epilepsy with lesions

This study aimed to evaluate high-frequency oscillations (HFOs), a potential biomarker of epileptic activity, using magnetoencephalography (MEG). We developed a new spatial filter, termed “gradient magnetic-oscillation topography” (GMOT), to visualize color-coded topographies on the brain surface using a spectrogram calculated at each sensor level. We enrolled 15 patients with lesions and intractable neocortical epilepsy who underwent focal resection surgery and preoperative MEG. We compared GMOT findings with those of the equivalent current dipole (ECD) and resected area based on intracranial video-electroencephalography (IVEEG) or intraoperative electrocorticography (ECoG) with respect to seizure outcomes. We also calculated the proportion of the power of each sensor relative to the entire head at each frequency band. GMOT successfully visualized the high-power gradient magnetic field at the fast ripple band (FR band, 201–330 Hz) and detected the highest power at the FR band around the lesion in 13 of the 15 patients. The resected area included both clustered ECDs and the highest power in the FR band on GMOT in 9 of the 15 patients. The resected area had a statistically higher proportion of power as the frequency band increased in the HFO group (p < 0.01). We visualized high power in the FR band of the brain surface. The areas of highest power in the FR band were correlated with epileptic focus based on IVEEG and intraoperative ECoG