Dissection of the signal transduction machinery responsible for the lysyl oxidase-like 4-mediated increase in invasive motility in triple-negative breast cancer cells: mechanistic insight into the integrin-ß1-NF-κB-MMP9 axis.

Background: Triple-negative breast cancer (TNBC) cells are a highly formidable cancer to treat. Nonetheless, by continued investigation into the molecular biology underlying the complex regulation of TNBC cell activity, vulnerabilities can be exposed as potential therapeutic targets at the molecular level. We previously revealed that lysyl oxidase-like 4 (LOXL4) promotes the invasiveness of TNBC cells via cell surface annexin A2 as a novel binding substrate of LOXL4, which promotes the abundant localization of integrin-ß1 at the cancer plasma membrane. However, it has yet to be uncovered how the LOXL4-mediated abundance of integrin-ß1 hastens the invasive outgrowth of TNBC cells at the molecular level. Methods: LOXL4-overexpressing stable clones were established from MDA-MB-231 cells and subjected to molecular analyses, real-time qPCR and zymography to clarify their invasiveness, signal transduction, and matrix metalloprotease (MMP) activity, respectively. Results: Our results show that LOXL4 potently promotes the induction of matrix metalloprotease 9 (MMP9) via activation of nuclear factor-κB (NF-κB). Our molecular analysis revealed that TNF receptor-associated factor 4 (TRAF4) and TGF-ß activated kinase 1 (TAK1) were required for the activation of NF-κB through Iκß kinase kinase (IKKα/ß) phosphorylation. Conclusion: Our results demonstrate that the newly identified LOXL4-mediated axis, integrin-ß1-TRAF4-TAK1-IKKα/ß-Iκßα-NF-κB-MMP9, is crucial for TNBC cell invasiveness.

Drop impact on wet granular beds: effects of water-content on cratering.

Drop impact events on a wet granular bed show a rich variety by changing the substrate composition. We observe the drop impact onto dry/wet granular substrates with different grain sizes (50-400 µm) and water contents (0-22 vol%). Despite the fixed impactor conditions (impact velocity: 4.0 m s-1, water drop radius: 1.8 mm), the experiment reveals that the post-impact behaviors of both the impactor and target are strongly influenced by the substrate composition. We categorize these behaviors into several phases concerning liquid splashing and crater shapes left after the event. As these phases are relevant to each other, we measure the mechanical characteristics of the substrates and find that the onset of splashing and particle ejection is explained via the fracture of the substrate. Furthermore, we discuss several timescales of the event to understand the phase separations in more detail. Consequently, we find that the splashing phase and the crater shape are determined by competition among the timescales of impact, penetration, and contact.

S100A11 is involved in the progression of colorectal cancer through the desmosome-catenin-TCF signaling pathway.

Compiling evidence has indicated that S100A11 expression at high levels is closely associated with various cancer species. Consistent with the results reported elsewhere, we have also revealed that S100A11 is highly expressed in squamous cell carcinoma, mesothelioma, and pancreatic cancers and plays a crucial role in cancer progression when secreted into extracellular fluid. Those studies are all focused on the extracellular role of S100A11. However, most of S100A11 is still present within cancer cells, although the intracellular role of S100A11 in cancer cells has not been fully elucidated. Thus, we aimed to investigate S100A11 functions within cancer cells, primarily focusing on colorectal cancer cells, whose S100A11 is abundantly present in cells and still poorly studied cancer for the protein. Our efforts revealed that overexpression of S100A11 promotes proliferation and migration, and downregulation inversely dampens those cancer behaviors. To clarify how intracellular S100A11 aids cancer cell activation, we tried to identify S100A11 binding proteins, resulting in novel binding partners in the inner membrane, many of which are desmosome proteins. Our molecular approach defined that S100A11 regulates the expression level of DSG1, a component protein of desmosome, by which S100A11 activates the TCF pathway via promoting nuclear translocation of γ-catenin from the desmosome. The identified new pathway greatly helps to comprehend S100A11's nature in colorectal cancers and others.

Comparison of Protective Effects of Antidepressants Mediated by Serotonin Receptor in Aß-Oligomer-Induced Neurotoxicity.

Amyloid ß-peptide (Aß) synthesis and deposition are the primary factors underlying the pathophysiology of Alzheimer's disease (AD). Aß oligomer (Aßo) exerts its neurotoxic effects by inducing oxidative stress and lesions by adhering to cellular membranes. Though several antidepressants have been investigated as neuroprotective agents in AD, a detailed comparison of their neuroprotection against Aßo-induced neurotoxicity is lacking. Here, we aimed to elucidate the neuroprotective effects of clinically prescribed selective serotonin reuptake inhibitors, serotonin-norepinephrine reuptake inhibitors, and noradrenergic and specific serotonergic antidepressants at the cellular level and establish the underlying mechanisms for their potential clinical applications. Therefore, we compared the neuroprotective effects of three antidepressants, fluoxetine (Flx), duloxetine (Dlx), and mirtazapine (Mir), by their ability to prevent oxidative stress-induced cell damage, using SH-SY5Y cells, by evaluating cell viability, generation of reactive oxygen species (ROS) and mitochondrial ROS, and peroxidation of cell membrane phospholipids. These antidepressants exhibited potent antioxidant activity (Dlx > Mir > Flx) and improved cell viability. Furthermore, pretreatment with a 5-hydroxytryptamine 1A (5-HT1A) antagonist suppressed their effects, suggesting that the 5-HT1A receptor is involved in the antioxidant mechanism of the antidepressants' neuroprotection. These findings suggest the beneficial effects of antidepressant treatment in AD through the prevention of Aß-induced oxidative stress.

Continuous immunotherapy beyond progression in clinical practice for small cell lung cancer.

In non-small-cell lung cancer, continuous immune-checkpoint inhibitors (ICIs) beyond progression are often used in clinical practice. On the other hand, there is almost no data on whether the concept of continuous ICIs beyond progression can be adopted in small-cell lung cancer (SCLC). We describe the effectiveness of continuous ICIs beyond progression in SCLC. Medical courses of SCLC patients treated with chemo-immunotherapy were retrospectively reviewed at our hospital. The study included 36 patients with a median age of 73 years (range 46-83 years) who introduced chemo-immunotherapy between September 2019 and December 2022. Atezolizumab and durvalumab in combination with platinum plus etoposide were administered in 24 and 12 patients, respectively. The overall response rate was 67% and the disease control rate was 86%. The median progression-free survival and time to treatment failure (TTF) were 5.1 and 10.3 months, respectively. The median cycle of ICIs was 5 (range 1-42). The median overall survival was 13.6 months. ICIs were administered beyond progression in 14 (39%) patients: five were treated again with chemo-immunotherapy and local ablative radiotherapy, four with local ablative radiotherapy and continuous ICIs, three with chemo-immunotherapy, and two with continuous ICIs alone. TTF exceeded 12 months in 12 (86%) of the 14 cases, six of which were still on ICIs. Adverse events ≥grade 3 were observed in 21 (58%) patients. A notable TTF suggested a benefit of continuous ICIs beyond progression. The concept could be suitably adopted and provide a favorable prognosis in selected cases of SCLC that were previously regarded as an aggressive malignancy.

Lysyl oxidase-like 4 promotes the invasiveness of triple-negative breast cancer cells by orchestrating the invasive machinery formed by annexin A2 and S100A11 on the cell surface.

Background: Our earlier research revealed that the secreted lysyl oxidase-like 4 (LOXL4) that is highly elevated in triple-negative breast cancer (TNBC) acts as a catalyst to lock annexin A2 on the cell membrane surface, which accelerates invasive outgrowth of the cancer through the binding of integrin-ß1 on the cell surface. However, whether this machinery is subject to the LOXL4-mediated intrusive regulation remains uncertain. Methods: Cell invasion was assessed using a transwell-based assay, protein-protein interactions by an immunoprecipitation-Western blotting technique and immunocytochemistry, and plasmin activity in the cell membrane by gelatin zymography. Results: We revealed that cell surface annexin A2 acts as a receptor of plasminogen via interaction with S100A10, a key cell surface annexin A2-binding factor, and S100A11. We found that the cell surface annexin A2/S100A11 complex leads to mature active plasmin from bound plasminogen, which actively stimulates gelatin digestion, followed by increased invasion. Conclusion: We have refined our understanding of the role of LOXL4 in TNBC cell invasion: namely, LOXL4 mediates the upregulation of annexin A2 at the cell surface, the upregulated annexin 2 binds S100A11 and S100A10, and the resulting annexin A2/S100A11 complex acts as a receptor of plasminogen, readily converting it into active-form plasmin and thereby enhancing invasion.

Theory and data analysis of player and team ball possession time in football.

In this study, the stochastic properties of player and team ball possession times in professional football matches are examined. Data analysis shows that player possession time follows a gamma distribution and the player count of a team possession event follows a mixture of two geometric distributions. We propose a formula for expressing team possession time in terms of player possession time and player count in a team's possession, verifying its validity through data analysis. Furthermore, we calculate an approximate form of the distribution of team possession time and study its asymptotic property.

Phosphorylated SARM1 is involved in the pathological process of rotenone-induced neurodegeneration.

Sterile alpha and Toll/interleukin receptor motif-containing protein 1 (SARM1) is a NAD+ hydrolase that plays a key role in axonal degeneration and neuronal cell death. We reported that c-Jun N-terminal kinase (JNK) activates SARM1 through phosphorylation at Ser-548. The importance of SARM1 phosphorylation in the pathological process of Parkinson's disease (PD) has not been determined. We thus conducted the present study by using rotenone (an inducer of PD-like pathology) and neurons derived from induced pluripotent stem cells (iPSCs) from healthy donors and a patient with familial PD PARK2 (FPD2). The results showed that compared to the healthy neurons, FPD2 neurons were more vulnerable to rotenone-induced stress and had higher levels of SARM1 phosphorylation. Similar cellular events were obtained when we used PARK2-knockdown neurons derived from healthy donor iPSCs. These events in both types of PD-model neurons were suppressed in neurons treated with JNK inhibitors, Ca2+-signal inhibitors, or by a SARM1-knockdown procedure. The degenerative events were enhanced in neurons overexpressing wild-type SARM1 and conversely suppressed in neurons overexpressing the SARM1-S548A mutant. We also detected elevated SARM1 phosphorylation in the midbrain of PD-model mice. The results indicate that phosphorylated SARM1 plays an important role in the pathological process of rotenone-induced neurodegeneration.

[Non-Small Cell Lung Cancer].

Oligometastases(Oligo-meta)were first defined in breast cancer, and the criteria are a small number of metastases and the possibility of local treatment for all lesions. It has been pointed out that the addition of local therapy to standard therapy may prolong survival in the treatment of Oligo-meta, and the same is possible in non-small cell lung cancer(NSCLC). Since NSCLC can metastasize to various organs, local treatment options for Oligo-meta differ depending on the metastatic organ. Therefore, when treating Oligo-meta in NSCLC, multidisciplinary treatment is necessary, considering various conditions such as patient background and metastatic sites, and in collaboration with various departments. In recent years, the mainstay of treatment of NSCLC has shifted to immune checkpoint inhibitors. The treatment of Oligo-meta in combination with these drugs may enhance the therapeutic effect. Several clinical trials are currently underway for the treatment of Oligo-meta in NSCLC, combining local therapy with immune checkpoint inhibitors, and we look forward to the results of these trials.

Neuroprotective Potential of Raloxifene via G-Protein-Coupled Estrogen Receptors in Aß-Oligomer-Induced Neuronal Injury.

Amyloid-ß (Aß) is one of the causes of Alzheimer's disease (AD), damaging nerve membranes and inducing neurotoxicity. AD is more prevalent in female patients than in male patients, and women are more susceptible to developing AD due to the decline in estrogen levels around menopause. Raloxifene, a selective estrogen receptor modulator, exhibits protective effects by activating the transmembrane G-protein-coupled estrogen receptor (GPER). Additionally, raloxifene prevents mild cognitive impairment and restores cognition. However, the influence of raloxifene via GPER on highly toxic Aß-oligomers (Aßo)-induced neurotoxicity remains uncertain. In this study, we investigated the GPER-mediated neuroprotective effects of raloxifene against the neurotoxicity caused by Aßo-induced cytotoxicity. The impact of raloxifene on Aßo-induced cell damage was evaluated using measures such as cell viability, production of reactive oxygen species (ROS) and mitochondrial ROS, peroxidation of cell-membrane phospholipids, and changes in intracellular calcium ion concentration ([Ca2+]i) levels. Raloxifene hindered Aßo-induced oxidative stress and reduced excessive [Ca2+]i, resulting in improved cell viability. Furthermore, these effects of raloxifene were inhibited with pretreatment with a GPER antagonist. Our findings suggest that raloxifene safeguards against Aßo-induced neurotoxicity by modifying oxidative parameters and maintaining [Ca2+]i homeostasis. Raloxifene may prove effective in preventing and inhibiting the progression of AD.

Contributions of the N-terminal flanking residues of an antigenic peptide from the Japanese cedar pollen allergen Cry j 1 to the T-cell activation by HLA-DP5.

Cry j 1 is a major allergen present in Japanese cedar (Cryptomeria japonica) pollens. Peptides with the core sequence of KVTVAFNQF from Cry j 1 ('pCj1') bind to HLA-DP5 and activate Th2 cells. In this study, we noticed that Ser and Lys at positions -2 and -3, respectively, in the N-terminal flanking (NF) region to pCj1 are conserved well in HLA-DP5-binding allergen peptides. A competitive binding assay showed that the double mutation of Ser(-2) and Lys(-3) to Glu [S(P-2)E/K(P-3)E] in a 13-residue Cry j 1 peptide (NF-pCj1) decreased its affinity for HLA-DP5 by about 2-fold. Similarly, this double mutation reduced, by about 2-fold, the amount of NF-pCj1 presented on the surface of mouse antigen-presenting dendritic cell line 1 (mDC1) cells stably expressing HLA-DP5. We established NF-pCj1-specific and HLA-DP5-restricted CD4+ T-cell clones from HLA-DP5 positive cedar pollinosis (CP) patients, and analyzed their IL-2 production due to the activation of mouse TG40 cells expressing the cloned T-cell receptor by the NF-pCj1-presenting mDC1 cells. The T-cell activation was actually decreased by the S(P-2)E/K(P-3)E mutation, corresponding to the reduction in the peptide presentation by this mutation. In contrast, the affinity of NF-pCj1·HLA-DP5 for the T-cell receptor was not affected by the S(P-2)E/K(P-3)E mutation, as analyzed by surface plasmon resonance. Considering the positional and side-chain differences of these NF residues from previously reported T-cell activating sequences, the mechanisms of enhanced T-cell activation by Ser(-2) and Lys(-3) of NF-pCj1 may be novel.

Depression as a Prodromal Symptom of Neurodegenerative Diseases.

Neurodegenerative diseases can manifest as psychiatric symptoms in the prodromal phase, before the onset of core symptoms such as neurological, motor, and cognitive symptoms. Positron emission tomography (PET) has made it possible to detect the pathology of some neurodegenerative diseases in vivo. Many studies have indicated that depression is a preclinical symptom of neurodegenerative diseases. Approximately 10% of non-demented participants with depression developed Alzheimer's disease (AD) during the follow-up period. The prevalence of depression/dysphoria was 42.9% in the preclinical stage of dementia with Lewy bodies. Depression was present in 33.3% of patients with preclinical behavioral-variant frontotemporal lobar degeneration. Approximately 10% of patients had a history of depression at the time of diagnosis with Parkinson's disease. PET studies have revealed the pathology of neurodegenerative diseases in some cases of geriatric depression. Increased brain amyloid-beta deposition in late-onset depression is a possible reflection of prodromal AD. The severity of depression was significantly associated with greater inferior temporal tau and marginally associated with greater entorhinal cortex tau, and depression was associated with significantly greater mean cortical tau deposition. Thus, the presence of depression as a preclinical/prodromal symptom of neurodegenerative diseases has been demonstrated by epidemiological, pathological, and biomarker studies. A growing body of evidence from PET studies indicates that some cases of geriatric depression have pathologies of degenerative neurological disease. In the future, it is expected that PET will be utilized as an imaging biomarker for diagnosis of psychiatric disorders and development of new therapeutic agents.

STAT1/3 signaling suppresses axon degeneration and neuronal cell death through regulation of NAD+-biosynthetic and consuming enzymes.

Nicotinamide adenine dinucleotide (NAD)+-biosynthetic and consuming enzymes are involved in various intracellular events through the regulation of NAD+ metabolism. Recently, it has become clear that alterations in the expression of NAD+-biosynthetic and consuming enzymes contribute to the axonal stability of neurons. We explored soluble bioactive factor(s) that alter the expression of NAD+-metabolizing enzymes and found that cytokine interferon (IFN)-γ increased the expression of nicotinamide nucleotide adenylyltransferase 2 (NMNAT2), an NAD+-biosynthetic enzyme. IFN-γ activated signal transducers and activators of transcription 1 and 3 (STAT1/3) followed by c-Jun N-terminal kinase (JNK) suppression. As a result, STAT1/3 increased the expression of NMNAT2 at both mRNA and protein levels in a dose- and time-dependent manner and, at the same time, suppressed activation of sterile alpha and Toll/interleukin receptor motif-containing 1 (SARM1), an NAD+-consuming enzyme, and increased intracellular NAD+ levels. We examined the protective effect of STAT1/3 signaling against vincristine-mediated cell injury as a model of chemotherapy-induced peripheral neuropathy (CIPN), in which axonal degeneration is involved in disease progression. We found that IFN-γ-mediated STAT1/3 activation inhibited vincristine-induced downregulation of NMNAT2 and upregulation of SARM1 phosphorylation, resulting in modest suppression of subsequent neurite degradation and cell death. These results indicate that STAT1/3 signaling induces NMNAT2 expression while simultaneously suppressing SARM1 phosphorylation, and that both these actions contribute to suppression of axonal degeneration and cell death.

Lysyl oxidase-like 4 exerts an atypical role in breast cancer progression that is dependent on the enzymatic activity that targets the cell-surface annexin A2.

Background: LOX family members are reported to play pivotal roles in cancer. Unlike their enzymatic activities in collagen cross-linking, their precise cancer functions are unclear. We revealed that LOXL4 is highly upregulated in breast cancer cells, and we thus sought to define an unidentified role of LOXL4 in breast cancer. Methods: We established the MDA-MB-231 sublines MDA-MB-231-LOXL4 mutCA and -LOXL4 KO, which stably overexpress mutant LOXL4 that loses its catalytic activity and genetically ablates the intrinsic LOXL4 gene, respectively. In vitro and in vivo evaluations of these cells' activities of cancer outgrowth were conducted by cell-based assays in cultures and an orthotopic xenograft model, respectively. The new target (s) of LOXL4 were explored by the MS/MS analytic approach. Results: Our in vitro results revealed that both the overexpression of mutCA and the KO of LOXL4 in cells resulted in a marked reduction of cell growth and invasion. Interestingly, the lowered cellular activities observed in the engineered cells were also reflected in the mouse model. We identified a novel binding partner of LOXL4, i.e., annexin A2. LOXL4 catalyzes cell surface annexin A2 to achieve a cross-linked multimerization of annexin A2, which in turn prevents the internalization of integrin ß-1, resulting in the locking of integrin ß-1 on the cell surface. These events enhance the promotion of cancer cell outgrowth. Conclusions: LOXL4 has a new role in breast cancer progression that occurs via an interaction with annexin A2 and integrin ß-1 on the cell surface.

Novel extracellular role of REIC/Dkk-3 protein in PD-L1 regulation in cancer cells.

The adenovirus-REIC/Dkk-3 expression vector (Ad-REIC) has been the focus of numerous clinical studies due to its potential for the quenching of cancers. The cancer-suppressing mechanisms of the REIC/DKK-3 gene depend on multiple pathways that exert both direct and indirect effects on cancers. The direct effect is triggered by REIC/Dkk-3-mediated ER stress that causes cancer-selective apoptosis, and the indirect effect can be classified in two ways: (i) induction, by Ad-REIC-mis-infected cancer-associated fibroblasts, of the production of IL-7, an important activator of T cells and NK cells, and (ii) promotion, by the secretory REIC/Dkk-3 protein, of dendritic cell polarization from monocytes. These unique features allow Ad-REIC to exert effective and selective cancer-preventative effects in the manner of an anticancer vaccine. However, the question of how the REIC/Dkk-3 protein leverages anticancer immunity has remained to be answered. We herein report a novel function of the extracellular REIC/Dkk-3-namely, regulation of an immune checkpoint via modulation of PD-L1 on the cancer-cell surface. First, we identified novel interactions of REIC/Dkk-3 with the membrane proteins C5aR, CXCR2, CXCR6, and CMTM6. These proteins all functioned to stabilize PD-L1 on the cell surface. Due to the dominant expression of CMTM6 among the proteins in cancer cells, we next focused on CMTM6 and observed that REIC/Dkk-3 competed with CMTM6 for PD-L1, thereby liberating PD-L1 from its complexation with CMTM6. The released PD-L1 immediately underwent endocytosis-mediated degradation. These results will enhance our understanding of not only the physiological nature of the extracellular REIC/Dkk-3 protein but also the Ad-REIC-mediated anticancer effects. KEY MESSAGES: • REIC/Dkk-3 protein effectively suppresses breast cancer progression through an acceleration of PD-L1 degradation. • PD-L1 stability on the cancer cell membrane is kept high by binding with mainly CMTM6. • Competitive binding of REIC/Dkk-3 protein with CMTM6 liberates PD-L1, leading to PD-L1 degradation.

LOXL1 and LOXL4 are novel target genes of the Zn2+-bound form of ZEB1 and play a crucial role in the acceleration of invasive events in triple-negative breast cancer cells.

Background: EMT has been proposed to be a crucial early event in cancer metastasis. EMT is rigidly regulated by the action of several EMT-core transcription factors, particularly ZEB1. We previously revealed an unusual role of ZEB1 in the S100A8/A9-mediated metastasis in breast cancer cells that expressed ZEB1 at a significant level and showed that the ZEB1 was activated on the MCAM-downstream pathway upon S100A8/A9 binding. ZEB1 is well known to require Zn2+ for its activation based on the presence of several Zn-finger motifs in the transcription factor. However, how Zn2+-binding works on the pleiotropic role of ZEB1 through cancer progression has not been fully elucidated. Methods: We established the engineered cells, MDA-MB-231 MutZEB1 (MDA-MutZEB1), that stably express MutZEB1 (ΔZn). The cells were then evaluated in vitro for their invasion activities. Finally, an RNA-Seq analysis was performed to compare the gene alteration profiles of the established cells comprehensively. Results: MDA-MutZEB1 showed a significant loss of the EMT, ultimately stalling the invasion. Inclusive analysis of the transcription changes after the expression of MutZEB1 (ΔZn) in MDA-MB-231 cells revealed the significant downregulation of LOX family genes, which are known to play a critical role in cancer metastasis. We found that LOXL1 and LOXL4 remarkably enhanced cancer invasiveness among the LOX family genes with altered expression. Conclusions: These findings indicate that ZEB1 potentiates Zn2+-mediated transcription of plural EMT-relevant factors, including LOXL1 and LOXL4, whose upregulation plays a critical role in the invasive dissemination of breast cancer cells.

Clinical Results of Surgical Treatment for Comminuted Radial Head and Neck Fracture: Headless Compression Screws Versus Plate Fixation.

Background: We surgically treated comminuted radial head and neck fractures using headless compression screws, including multiple screws for the radial head and a single oblique screw for the radial neck. This study aimed to compare the clinical and radiological results for comminuted radial head and neck fractures between surgery using headless compression screws with a single oblique screw for the radial neck, our new procedure, and a plate system precontoured to the proximal radius. Methods: This retrospective study included 23 patients (11 and 12 in the screw and plate groups, respectively). The fractures were type 3 according to the Mason-Johnston classification modified by Broberg and Morrey. Clinical outcomes analyzed included the motion range of the elbow and forearm, Mayo Elbow Performance Score, and radiological assessments. In addition, postoperative complications were also investigated. The average follow-up was 18 months. Results: The bone union was achieved in all the patients, and there were no significant differences in clinical outcomes and radiological assessments except forearm supination (p = 0.02). Furthermore, additional surgical procedures were performed in one and five patients in the screw and plate groups, respectively (p = 0.16). Posterior nerve palsy was observed in two patients in the plate group. Complications were observed in one and six patients in the screw and plate groups, respectively (p = 0.07). Conclusion: Both surgical procedures achieved good clinical and radiological outcomes with bone and ligament injury repair. The screw group had a greater range of forearm supination than the plate group.

The Curcumin Derivative GT863 Protects Cell Membranes in Cytotoxicity by Aß Oligomers.

In Alzheimer's disease (AD), accumulation of amyloid ß-protein (Aß) is one of the major mechanisms causing neuronal cell damage. Disruption of cell membranes by Aß has been hypothesized to be the important event associated with neurotoxicity in AD. Curcumin has been shown to reduce Aß-induced toxicity; however, due to its low bioavailability, clinical trials showed no remarkable effect on cognitive function. As a result, GT863, a derivative of curcumin with higher bioavailability, was synthesized. The purpose of this study is to clarify the mechanism of the protective action of GT863 against the neurotoxicity of highly toxic Aß oligomers (Aßo), which include high-molecular-weight (HMW) Aßo, mainly composed of protofibrils in human neuroblastoma SH-SY5Y cells, focusing on the cell membrane. The effect of GT863 (1 µM) on Aßo-induced membrane damage was assessed by phospholipid peroxidation of the membrane, membrane fluidity, membrane phase state, membrane potential, membrane resistance, and changes in intracellular Ca2+ ([Ca2+]i). GT863 inhibited the Aßo-induced increase in plasma-membrane phospholipid peroxidation, decreased membrane fluidity and resistance, and decreased excessive [Ca2+]i influx, showing cytoprotective effects. The effects of GT863 on cell membranes may contribute in part to its neuroprotective effects against Aßo-induced toxicity. GT863 may be developed as a prophylactic agent for AD by targeting inhibition of membrane disruption caused by Aßo exposure.

The E2F6 Transcription Factor is Associated with the Mammalian SUZ12-Containing Polycomb Complex.

The Polycomb group protein (PcG) SUZ12 forms Polycomb repressive complexes together with histone methyltransferase EZH2. Although the complexes have been demonstrated to be involved in epigenetic maintenance of gene expression in a transcriptional repressive state, it is unclear how they are recruited to the target genes. Here we report that SUZ12 directly interacts with site-specific transcriptional repressor E2F6 and forms a complex together with EZH2. SUZ12 interacts with E2F6 selectively among the E2F family proteins and E2F6- containing SUZ12-EZH2 complex was biochemically purified from HEK293 cells stably expressing Flag-tagged SUZ12. Chromatin immunoprecipitation assays revealed the target genes of the E2F6-SUZ12-EZH2 complex. Contrary to expectation, the promoter regions of these genes are not or only weakly tri-methylated at histone H3-K27, and their expression is down-regulated by depletion of EZH2. Given that the transactivation function of SUZ12-EZH2 has been previously reported, the inhibitory effect on E2F6-mediated transcriptional repression by physical interaction can be considered a candidate mechanism of gene activation by these PcGs.