Truncated GPNMB, a microglial transmembrane protein, serves as a scavenger receptor for oligomeric β-amyloid peptide1-42 in primary type 1 microglia

Glycoprotein non-metastatic melanoma protein B (GPNMB) is up-regulated in one subtype of microglia (MG) surrounding senile plaque depositions of amyloid-beta (Aβ) peptides. However, whether the microglial GPNMB can recognize the fibrous Aβ peptides as ligands remains unknown. In this study, we report that the truncated form of GPNMB, the antigen for 9F5, serves as a scavenger receptor for oligomeric Aβ1-42 (o-Aβ1-42 ) in rat primary type 1 MG. 125 I-labeled o-Aβ1-42 exhibited specific and saturable endosomal/lysosomal degradation in primary-cultured type 1 MG from GPNMB-expressing wild-type mice, whereas the degradation activity was markedly reduced in cells from Gpnmb-knockout mice. The Gpnmb-siRNA significantly inhibits the degradation of 125 I-o-Aβ1-42 by murine microglial MG5 cells. Therefore, GPNMB contributes to mouse MG's o-Aβ1-42 clearance. In rat primary type 1 MG, the cell surface expression of truncated GPNMB was confirmed by a flow cytometric analysis using a previously established 9F5 antibody. 125 I-labeled o-Aβ1-42 underwent endosomal/lysosomal degradation by rat primary type 1 MG in a dose-dependent fashion, while the 9F5 antibody inhibited the degradation. The binding of 125 I-o-Aβ1-42 to the rat primary type 1 MG was inhibited by 42% by excess unlabeled o-Aβ1-42 , and by 52% by the 9F5 antibody. Interestingly, the 125 I-o-Aβ1-42 degradations by MG-like cells from human-induced pluripotent stem cells was inhibited by the 9F5 antibody, suggesting that truncated GPNMB also serve as a scavenger receptor for o-Aβ1-42 in human MG. Our study demonstrates that the truncated GPNMB (the antigen for 9F5) binds to oligomeric form of Aβ1-42 and functions as a scavenger receptor on MG, and 9F5 antibody can act as a blocking antibody for the truncated GPNMB.

Metabolic reprograming of cancer as a therapeutic target

Our understanding of metabolic reprogramming in cancer has tremendously improved along with the technical progression of metabolomic analysis. Metabolic changes in cancer cells proved much more complicated than the classical Warburg effect. Previous studies have approached metabolic changes as therapeutic and/or chemopreventive targets. Recently, several clinical trials have reported anti-cancer agents associated with metabolism. However, whether cancer cells are dependent on metabolic reprogramming or favor suitable conditions remains nebulous. Both scenarios are possibly intertwined. Identification of downstream molecules and the understanding of mechanisms underlying reprogrammed metabolism can improve the effectiveness of cancer therapy. Here, we review several examples of the metabolic reprogramming of cancer cells and the therapies targeting the metabolism-related molecules as well as discuss practical approaches to improve the next generation of cancer therapies focused on the metabolic reprogramming of cancer.

Formation and evolution of carbonaceous asteroid Ryugu: Direct evidence from returned samples

Samples of the carbonaceous asteroid Ryugu were brought to Earth by the Hayabusa2 spacecraft. We analyzed 17 Ryugu samples measuring 1 to 8 millimeters. Carbon dioxide-bearing water inclusions are present within a pyrrhotite crystal, indicating that Ryugu's parent asteroid formed in the outer Solar System. The samples contain low abundances of materials that formed at high temperatures, such as chondrules and calcium- and aluminum-rich inclusions. The samples are rich in phyllosilicates and carbonates, which formed through aqueous alteration reactions at low temperature, high pH, and water/rock ratios of <1 (by mass). Less altered fragments contain olivine, pyroxene, amorphous silicates, calcite, and phosphide. Numerical simulations, based on the mineralogical and physical properties of the samples, indicate that Ryugu's parent body formed ~2 million years after the beginning of Solar System formation.

Nucleolar Stress Response via Ribosomal Protein L11 Regulates Topoisomerase Inhibitor Sensitivity of P53-Intact Cancers

Nucleolar stress response is caused by perturbations in ribosome biogenesis, induced by the inhibition of ribosomal RNA processing and synthesis, as well as ribosome assembly. This response induces p53 stabilization and activation via ribosomal protein L11 (RPL11), suppressing tumor progression. However, anticancer agents that kill cells via this mechanism, and their relationship with the therapeutic efficiency of these agents, remain largely unknown. Here, we sought to investigate whether topoisomerase inhibitors can induce nucleolar stress response as they reportedly block ribosomal RNA transcription. Using rhabdomyosarcoma and rhabdoid tumor cell lines that are sensitive to the nucleolar stress response, we evaluated whether nucleolar stress response is associated with sensitivity to topoisomerase inhibitors ellipticine, doxorubicin, etoposide, topotecan, and anthracyclines. Cell proliferation assay indicated that small interfering RNA-mediated RPL11 depletion resulted in decreased sensitivity to topoisomerase inhibitors. Furthermore, the expression of p53 and its downstream target proteins via western blotting showed the suppression of p53 pathway activation upon RPL11 knockdown. These results suggest that the sensitivity of cancer cells to topoisomerase inhibitors is regulated by RPL11-mediated nucleolar stress responses. Thus, RPL11 expression may contribute to the prediction of the therapeutic efficacy of topoisomerase inhibitors and increase their therapeutic effect of topoisomerase inhibitors.

Intraosseous carcinoma of the anterior maxilla identified as the occult primary tumour of carcinoma of unknown primary

Carcinoma of unknown primary (CUP) is defined as lymph node metastasis without a detectable origin until after the initial treatment has been performed. The most common occult primary site in the head and neck, as revealed by a review of the published literature, is the oropharynx. An occult primary site in the oral region is extremely rare. We report a rare case of head and neck CUP (HNCUP) in a 69-year-old female patient, wherein the occult primary lesion was a primary intraosseous carcinoma (PIOC) invading the anterior maxilla. During the course of the initial diagnostic workup, no primary lesion could be identified; however, cervical lymph node metastasis to left levels IB and IIA were observed in the patient. A neck dissection followed by adjuvant radiotherapy was performed. However, the PIOC of the anterior maxilla was identified 6 months after neck treatment and was confirmed as the occult primary tumour of the HNCUP. This case is quite rare and required a comprehensive workup to guide optimal treatment. Careful follow-up or active biopsy should be considered if osteolytic changes are observed in the jaw.

Association between Dysfunction of the Nucleolar Stress Response and Multidrug Resistance in Pediatric Acute Lymphoblastic Leukemia

Simple Summary

Pediatric patients with B-cell precursor acute lymphoblastic leukemia (BCP-ALL) relapse or are refractory to chemotherapy despite the low frequency of TP53 mutations. The nucleolar stress response is one of the mechanisms that activate P53 by ribosomal protein L11 (RPL11). We hypothesized that the lack of nucleolar stress response is related to chemoresistance and relapse in some pediatric BCP-ALL cases. We revealed that clinical BCP-ALL therapeutics, such as 6-mercaptopurine, methotrexate, daunorubicin, and cytarabine, induced the nucleolar stress response, and its treatment susceptibility was dependent on the nucleolar stress response. Furthermore, we observed decreased RPL11 expression at relapse in seven children with BCP-ALL in comparison to that at onset. Our findings provide new insights into the anti-leukemia mechanism in BCP-ALL and multidrug resistance and relapse via the nucleolar stress response, suggesting that the nucleolar stress response may be a potential therapeutic strategy to predict chemosensitivity and improve chemoresistance in pediatric BCP-ALL.

Abstract

Approximately 20% of pediatric patients with B-cell precursor acute lymphoblastic leukemia (BCP-ALL) relapse or are refractory to chemotherapy despite the low frequency of TP53 mutations. The nucleolar stress response is a P53-activating mechanism via MDM2 inhibition by ribosomal protein L11 (RPL11). We analyzed the role of the nucleolar stress response using BCP-ALL cell lines and patient samples by drug sensitivity tests, Western blotting, and reverse transcription polymerase chain reaction. We revealed that the nucleolar stress response works properly in TP53 wild-type human BCP-ALL cell lines. Next, we found that 6-mercaptopurine, methotrexate, daunorubicin, and cytarabine had anti-leukemic effects via the nucleolar stress response within BCP-ALL treatment. Comparing the samples at onset and relapse in children with BCP-ALL, RPL11 mRNA expression decreased at relapse in seven of nine cases. Furthermore, leukemia cells with relapse acquired resistance to these four drugs and suppressed P53 and RPL11 expression. Our findings suggest that the nucleolar stress response is a novel anti-leukemia mechanism in BCP-ALL. As these four drugs are key therapeutics for BCP-ALL treatment, dysfunction of the nucleolar stress response may be related to clinical relapse or refractoriness. Nucleolar stress response may be a target to predict and improve the chemotherapy effect for pediatric BCP-ALL.

Prevalence of and risk factors for depressive symptoms in non-tuberculous mycobacterial pulmonary disease

BACKGROUND: The presence of depressive symptoms in patients with non-tuberculous mycobacterial pulmonary disease (NTM-PD) is an important research topic; however, the prevalence of depressive symptoms and the factors that influence their development are unclear.OBJECTIVE: To analyse the association between CES-D (Center for Epidemiological Studies Depression Scale) scores and clinical parameters such as age, disease duration, pulmonary function, imaging findings, blood data, physical functions, sleep disturbances, respiratory symptoms and health-related quality of life (HRQOL).METHODS: We conducted a cross-sectional retrospective study of 114 patients with NTM-PD at a single centre from March 2016 to January 2021 to evaluate the relationship between CES-D scores and clinical parameters.RESULTS: Participants had a median age of 64 years; 32.5% of them had depressive symptoms. Disease duration, albumin, C-reactive protein, pulmonary function, dyspnoea, exercise capacity, respiratory symptoms, cough-related HRQOL and sleep disturbances were associated with depressive symptoms. Binomial logistic regression analyses indicated that the CES-D score was significantly associated with cough-related HRQOL and sleep disturbances.CONCLUSION: A high percentage of NTM-PD patients in this study experienced depressive symptoms, and these patients had abnormalities of various clinical parameters. Cough-related HRQOL and sleep disturbance had a strong influence on the development of depressive symptoms.

BHLHE41/DEC2 Expression Induces Autophagic Cell Death in Lung Cancer Cells and Is Associated with Favorable Prognosis for Patients with Lung Adenocarcinoma

Lung cancer constitutes a threat to human health. BHLHE41 plays important roles in circadian rhythm and cell differentiation as a negative regulatory transcription factor. This study investigates the role of BHLHE41 in lung cancer progression. We analyzed BHLHE41 function via in silico and immunohistochemical studies of 177 surgically resected non-small cell lung cancer (NSCLC) samples and 18 early lung squamous cell carcinoma (LUSC) cases. We also examined doxycycline (DOX)-inducible BHLHE41-expressing A549 and H2030 adenocarcinoma cells. BHLHE41 expression was higher in normal lung than in lung adenocarcinoma (LUAD) tissues and was associated with better prognosis for the overall survival (OS) of patients. In total, 15 of 132 LUAD tissues expressed BHLHE41 in normal lung epithelial cells. Staining was mainly observed in adenocarcinoma in situ and the lepidic growth part of invasive cancer tissue. BHLHE41 expression constituted a favorable prognostic factor for OS (p = 0.049) and cause-specific survival (p = 0.042) in patients with LUAD. During early LUSC, 7 of 18 cases expressed BHLHE41, and this expression was inversely correlated with the depth of invasion. DOX suppressed cell proliferation and increased the autophagy protein LC3, while chloroquine enhanced LC3 accumulation and suppressed cell death. In a xenograft model, DOX suppressed tumor growth. Our results indicate that BHLHE41 expression prevents early lung tumor malignant progression by inducing autophagic cell death in NSCLC.

Health-related quality of life associates with clinical parameters in patients with NTM pulmonary disease

BACKGROUND: Previous studies have shown a reduction in health-related quality of life (HRQoL) in patients with non-tuberculous mycobacterial pulmonary disease (NTM-PD). However, the causes of this decline and the factors that contribute to it are unknown. This study was conducted to analyse the association between the St George´s Respiratory Questionnaire (SGRQ) and clinical parameters, including age, disease duration, body composition, pulmonary function, chest X-ray findings, blood data and physical function.METHODS: We performed a single-centre, cross-sectional, retrospective study of 101 patients with NTM-PD from December 2016 to October 2019. The relationship between the SGRQ scores and clinical parameters was evaluated.RESULTS: The median patient age was 67.0 years. Pulmonary function, radiological score, albumin levels, C-reactive protein levels and incremental shuttle walk test distance (ISWD) were significantly correlated with the total and component scores on the SGRQ. Multiple regression analysis showed that the SGRQ score was significantly associated with radiological score, pulmonary function and ISWD.CONCLUSION: This study was the first to assess the effect of clinical parameters on the SGRQ in patients with NTM-PD. HRQoL as determined using the SGRQ was associated with the radiological score, pulmonary function and ISWD in patients with NTM-PD.

ALKBH4 promotes tumourigenesis with a poor prognosis in non-small-cell lung cancer

The human AlkB homolog family (ALKBH) of proteins play a critical role in some types of cancer. However, the expression and function of the lysine demethylase ALKBH4 in cancer are poorly understood. Here, we examined the expression and function of ALKBH4 in non-small-cell lung cancer (NSCLC) and found that ALKBH4 was highly expressed in NSCLC, as compared to that in adjacent normal lung tissues. ALKBH4 knockdown significantly induced the downregulation of NSCLC cell proliferation via cell cycle arrest at the G1 phase of in vivo tumour growth. ALKBH4 knockdown downregulated E2F transcription factor 1 (E2F1) and its target gene expression in NSCLC cells. ALKBH4 and E2F1 expression was significantly correlated in NSCLC clinical specimens. Moreover, patients with high ALKBH4 expression showed a poor prognosis, suggesting that ALKBH4 plays a pivotal tumour-promoting role in NSCLC.

Development of a highly sensitive method for the quantitative analysis of modified nucleosides using UHPLC-UniSpray-MS/MS

There are more than 150 types of naturally occurring modified nucleosides, which are believed to be involved in various biological processes. Recently, an ultrahigh performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UHPLC-ESI-MS/MS) technique has been developed to measure low levels of modified nucleosides. A comprehensive analysis of modified nucleosides will lead to a better understanding of intracellular ribonucleic acid modification, but this analysis requires high-sensitivity measurements. In this perspective, we established a highly sensitive and quantitative method using the newly developed ion source, UniSpray. A mass spectrometer was used with a UniSpray source in positive ion mode. Our UHPLC-UniSpray-MS/MS methodology separated and detected the four major nucleosides, 42 modified nucleosides, and dG15N5 (internal standard) in 15 min. The UniSpray method provided good correlation coefficients (>0.99) for all analyzed nucleosides, and a wide range of linearity for 35 of the 46 nucleosides. Additionally, the accuracy and precision values satisfied the criteria of <15% for higher concentrations and <20% for the lowest concentrations of all nucleosides. We also investigated whether this method could measure nucleosides in biological samples using mouse tissues and non-small cell lung cancer clinical specimens. We were able to detect 43 and 31 different modified nucleosides from mouse and clinical tissues, respectively. We also found significant differences in the levels of N6-methyl-N6-threonylcarbamoyladenosine (m6t6A), 1-methylinosine (m1I), 2'-O-methylcytidine (Cm), 5-carbamoylmethyluridine (ncm5U), 5-methoxycarbonylmethyl-2-thiouridine (mcm5S2U), and 5-methoxycarbonylmethyl-2'-O-methyluridine (mcm5Um) between cancerous and noncancerous tissues. In conclusion, we developed a highly sensitive methodology using UHPLC-UniSpray-MS/MS to simultaneously detect and quantify modified nucleosides, which can be used for analysis of biological samples.

Involvement of ribosomal protein L11 expression in sensitivity of gastric cancer against 5-FU

5-Fluorouracil (5-FU) is widely used in the treatment of various types of solid cancer. Our study showed that ribosomal protein L11 (RPL11) was a crucial factor affecting sensitivity of gastric cancer to 5-FU, implying that RPL11 expression is a potential biomarker for predicting 5-FU sensitivity. Kaplan-Meier survival analysis indicated that high RPL11 expression in gastric cancer patients treated with 5-FU was significantly associated with good prognosis. It was therefore investigated whether RPL11 affected the sensitivity of gastric cancer against 5-FU using four human gastric cancer cell lines, MKN45 (wild-type TP53 gene), NUGC4 (wild-type), MKN7 (mutated), and KE39 cells (mutated). In vitro assays demonstrated that RPL11 knockdown in gastric cancer cell lines carrying the TP53 wild-type gene attenuated 5-FU-induced cell growth suppression and activation of the P53 pathway, but not in cells carrying mutated TP53, suggesting that 5-FU suppresses tumor progression via RPL11-mediated activation of the P53 pathway in gastric cancer. The present study provides a potential therapeutic strategy for improving 5-FU resistance in gastric cancer by elevating RPL11 expression.

Formin-like 1 (FMNL1) Is Associated with Glioblastoma Multiforme Mesenchymal Subtype and Independently Predicts Poor Prognosis

Glioblastoma multiforme (GBM), the most common primary malignant brain tumor in adults, is characterized by rapid proliferation, aggressive migration, and invasion into normal brain tissue. Formin proteins have been implicated in these processes. However, the role of formin-like 1 (FMNL1) in cancer remains unclear. We studied FMNL1 expression in glioblastoma samples using immunohistochemistry. We sought to analyze the correlation between FMNL1 expression, clinicopathologic variables, and patient survival. Migration and invasion assays were used to verify the effect of FMNL1 on glioblastoma cell lines. Microarray data were downloaded from The Cancer Genome Atlas and analyzed using gene set enrichment analysis (GSEA). FMNL1 was an independent predictor of poor prognosis in a cohort of 217 glioblastoma multiforme cases (p < 0.001). FMNL1 expression was significantly higher in the mesenchymal subtype. FMNL1 upregulation and downregulation were associated with mesenchymal and proneural markers in the GSEA, respectively. These data highlight the important role of FMNL1 in the neural-to-mesenchymal transition. Conversely, FMNL1 downregulation suppressed glioblastoma multiforme cell migration and invasion via DIAPH1 and GOLGA2, respectively. FMNL1 downregulation also suppressed actin fiber assembly, induced morphological changes, and diminished filamentous actin. FMNL1 is a promising therapeutic target and a useful biomarker for GBM progression.

5-Aza-2-deoxycytidine Enhances the Sensitivity of 5-Fluorouracil by Demethylation of the Thymidine Phosphorylase Promoter

BACKGROUND/AIM

5-Aza-2-deoxycytidine (5-Aza-CdR) enhances the sensitivity to 5-fluorouracil (5-FU), but the molecular mechanism is not fully understood. The aim of this study was to investigate the molecular mechanism that enhances the sensitivity to 5-FU treated with 5-Aza-CdR via thymidine phosphorylase (TP).

MATERIALS AND METHODS

The sensitivity to drugs was determined on several cancer cell lines by the MTT assay. Protein and mRNA levels were examined by immunoblot and RT-PCR, respectively. Gene silencing, binding of Sp1 to DNA and methylation of DNA was performed by siRNA, ChIP assay and sodium bisulfate genomic sequencing, respectively.

RESULTS

Sp1-binding sites in the TP promoter were methylated in epidermoid carcinoma. 5-Aza-CdR demethylated Sp1-binding sites and enhanced sensitivity to 5-FU.

CONCLUSION

Demethylation of Sp1-binding sites by 5-Aza-CdR was a key factor enhancing 5-FU sensitivity, which may enable more effective treatments for cancer patients with the combination of 5-Aza-CdR and 5-FU.

Imaging of local structures affecting electrical transport properties of large graphene sheets by lock-in thermography

The distribution of defects and dislocations in graphene layers has become a very important concern with regard to the electrical and electronic transport properties of device applications. Although several experiments have shown the influence of defects on the electrical properties of graphene, these studies were limited to measuring microscopic areas because of their long measurement times. Here, we successfully imaged various local defects in a large area of chemical vapor deposition graphene within a reasonable amount of time by using lock-in thermography (LIT). The differences in electrical resistance caused by the micrometer-scale defects, such as cracks and wrinkles, and atomic-scale domain boundaries were apparent as nonuniform Joule heating on polycrystalline and epitaxially grown graphene. The present results indicate that LIT can serve as a fast and effective method of evaluating the quality and uniformity of large graphene films for device applications.

FEAT enhances INSL3 expression in testicular Leydig cells

FEAT, the protein encoded by methyltransferase-like 13 (METTL13), is aberrantly upregulated in most human cancers and potently drives tumorigenesis in vivo; however, its role in normal tissues remains elusive. Immunoblotting has displayed weak FEAT expression in normal human tissues, including the testis. Here, we found that FEAT is expressed in fetal and adult Leydig cells in the testis. FEAT knockdown using siRNA increased primary cilia formation in MA-10 Leydig tumor cells, accompanied by enhanced 5' adenosine monophosphate-activated protein kinase (AMPK) activation. Immunofluorescence analyses of FEAT-silenced MA-10 cells showed diminished insulin-like factor 3 (INSL3) expression. A male Mettl13^+/- mouse developed bilateral intraabdominal cryptorchidism, suggesting defective INSL3 production by fetal Leydig cells. Leydig cells from the mouse showed markedly decreased INSL3 protein by immunohistochemistry. Together, these results suggest that FEAT facilitates the INSL3 production in testicular Leydig cells that is essential for transabdominal testis migration.

Thymidine catabolism promotes NADPH oxidase-derived reactive oxygen species (ROS) signalling in KB and yumoto cells

Thymidine phosphorylase (TP) is a rate-limiting enzyme in the thymidine catabolic pathway. TP is identical to platelet-derived endothelial cell growth factor and contributes to tumour angiogenesis. TP induces the generation of reactive oxygen species (ROS) and enhances the expression of oxidative stress-responsive genes, such as interleukin (IL)-8. However, the mechanism underlying ROS induction by TP remains unclear. In the present study, we demonstrated that TP promotes NADPH oxidase-derived ROS signalling in cancer cells. NADPH oxidase inhibition using apocynin or small interfering RNAs (siRNAs) abrogated the induction of IL-8 and ROS in TP-expressing cancer cells. Meanwhile, thymidine catabolism induced by TP increased the levels of NADPH and intermediates of the pentose phosphate pathway (PPP). Both siRNA knockdown of glucose 6-phosphate dehydrogenase (G6PD), a rate-limiting enzyme in PPP, and a G6PD inhibitor, dihydroepiandrosterone, reduced TP-induced ROS production. siRNA downregulation of 2-deoxy-D-ribose 5-phosphate (DR5P) aldolase, which is needed for DR5P to enter glycolysis, also suppressed the induction of NADPH and IL-8 in TP-expressing cells. These results suggested that TP-mediated thymidine catabolism increases the intracellular NADPH level via the PPP, which enhances the production of ROS by NADPH oxidase and activates its downstream signalling.

Thymidine phosphorylase in cancer aggressiveness and chemoresistance

Thymidine phosphorylase (TP) is a rate-limiting enzyme in thymidine catabolism. TP has several important roles in biological and pharmacological mechanisms; importantly TP acts as an angiogenic factor and one of metabolic enzymes of fluoro-pyrimidine anticancer agents and modifies inflammation. Improving our understanding of the characteristics and functions of TP has led to the development of novel TP-based anticancer therapies. We recently reported that TP-dependent thymidine catabolism contributes to tumour survival in low nutrient conditions and the pathway from thymidine to the glycolysis cascade is affected in the context of physiological and metabolic conditions. In this review, we describe recent advancement in our understanding of TP, with a focus on cancer cell biology and the pharmacology of pyrimidine analogue anticancer agents. This review provides comprehensive understanding of the molecular mechanism of TP function in cancer.

A novel isolation method for cancer prognostic factors via the p53 pathway by a combination of in vitro and in silico analyses

Identifying new therapeutic target genes affecting the survival of patients with cancer is crucial for the development of new cancer therapies. Here, we developed a novel technology combining in vitro short hairpin RNA (shRNA) library screening and in silico analysis of the tumor transcriptome to identify prognostic factors via the p53 tumor-suppressor pathway. For initial screening, we screened 5,000 genes through selection of shRNAs in p53 wild-type tumor cells that altered sensitivity to the p53 activator actinomycin D (ActD) to identify p53 regulatory genes; shRNAs targeting 322 genes were obtained. Among these 322 genes, seven were prognostic factor candidates whose high expression increased ActD sensitivity while prolonging the survival period in patients with the p53 wild-type genotype. Conversely, we identified 33 genes as prognostic factor candidates among ActD-resistant genes related to a shortened survival period only in p53 wild-type tumors. These 40 genes had biological functions such as apoptosis, drug response, cell cycle checkpoint, and cell proliferation. The 40 genes selected by this method contained many known genes related to the p53 pathway and prognosis in patients with cancer. In summary, we developed an efficient screening method to identify p53-dependent prognostic factors with in vitro experimental data and database analysis.

Thymidine Catabolism as a Metabolic Strategy for Cancer Survival

Thymidine phosphorylase (TP), a rate-limiting enzyme in thymidine catabolism, plays a pivotal role in tumor progression; however, the mechanisms underlying this role are not fully understood. Here, we found that TP-mediated thymidine catabolism could supply the carbon source in the glycolytic pathway and thus contribute to cell survival under conditions of nutrient deprivation. In TP-expressing cells, thymidine was converted to metabolites, including glucose 6-phosphate, lactate, 5-phospho-α-D-ribose 1-diphosphate, and serine, via the glycolytic pathway both in vitro and in vivo. These thymidine-derived metabolites were required for the survival of cells under low-glucose conditions. Furthermore, activation of thymidine catabolism was observed in human gastric cancer. These findings demonstrate that thymidine can serve as a glycolytic pathway substrate in human cancer cells.

Filamin C promotes lymphatic invasion and lymphatic metastasis and increases cell motility by regulating Rho GTPase in esophageal squamous cell carcinoma

To establish treatments to improve the prognosis of cancer patients, it is necessary to find new targets to control metastasis. We found that expression of FilaminC (FLNC), a member of the actin binding and cross-linking filamin protein family is correlated with lymphatic invasion and lymphatic metastasis in esophageal squamous cell carcinoma (ESCC) by increasing cell motility through activation of Rho GTPase.

Immunohistochemistry analysis showed that FLNC expression in ESCC is associated with lymphatic invasion, metastasis, and prognosis. FLNC knockdown in esophageal cancer cell lines decreased cell migration in wound healing and transwell migration assays, and invasion in transwell migration assays. Furthermore, FLNC knockdown reduced the amount of activated Rac-1 (GTP-Rac1) and activated Cdc42 (GTP-Cdc42). Our results suggest that FLNC expression is a useful biomarker of ESCC metastatic tendency and that inhibiting FLNC function may be useful to control the metastasis of ESCC.

Interactions between Respiratory, Cardiac and Stepping Rhythms in Decerebrated Cats: Functional Hierarchical Structures of Biological Oscillators

Interactions are described of central origin between respiratory, cardiac and stepping rhythms during fictive locomotion in paralyzed, vagotomized, and decerebrated cats. Fictive locomotion was induced by tonic electrical stimulation of the mesencephalic locomotor region (MLR). The coherence between heart beat fluctuation, the efferent discharges of the phrenic, and the lateral gastrocnemius nerves was used to evaluate the strength of the coupling between those three rhythms. The heart beat rhythm was modulated by the centrally generated respiratory and stepping rhythms. The central respiratory rhythm was modulated by the centrally generated stepping rhythm. Based on the present findings, we have proposed a new model concerning the functional hierarchical structures of the three biological oscillators.

Plexin A1 signaling confers malignant phenotypes in lung cancer cells

Aberrant changes to several signaling pathways because of genetic mutations or increased cytokine production are critical for tumor cells to become malignant. Semaphorin 3A (SEMA3A) acts as a bivalent factor that suppresses or promotes tumor development in different pathological backgrounds. Previously, we showed that SEMA3A positively regulated the proliferative and glycolytic activities of mouse-derived Lewis lung carcinoma (LLC) cells. Plexins A1-A4 (PLXNA1-PLXNA4) are SEMA3A receptors; however, it is not known which subtype is critical for oncogenic SEMA3A signaling. We used LLC cells to investigate the role of PLXNA1 in oncogenic SEMA3A signaling. Using short hairpin RNA-mediated knockdown, we investigated the effects of constitutive inhibition of Plxna1 on cell proliferation, metabolic dependency, and epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) sensitivity. We found that Plxna1 knockdown did not affect apoptosis but resulted in decreased cell proliferation and reductions in mRNA expression levels of proliferation-marker genes, such as Ccnd1, Pcna, and Myc. In addition, we found decreased mRNA expression levels of glycolysis-associated genes, such as Pkm2 and Ldha, and decreased lactate production. In contrast, we found no changes in the mRNA expression levels of oxidative phosphorylation-associated genes, such as Cycs, Cox5a, and Atp5g1. We found that Plxna1 knockdown conferred resistance to glucose starvation but increased cytotoxicity to oligomycin. Plxna1 or Sema3a knockdown caused an increased sensitivity to the EGFR-TKIs gefitinib and erlotinib, in Lewis lung carcinoma (LLC) cells. These findings demonstrate that PLXNA1 mediates the acquisition of malignant phenotypes induced by autocrine SEMA3A signaling.

The novel monoclonal antibody 9F5 reveals expression of a fragment of GPNMB/osteoactivin processed by furin-like protease(s) in a subpopulation of microglia in neonatal rat brain

To differentiate subtypes of microglia (MG), we developed a novel monoclonal antibody, 9F5, against one subtype (type 1) of rat primary MG. The 9F5 showed high selectivity for this cell type in Western blot and immunocytochemical analyses and no cross-reaction with rat peritoneal macrophages (Mφ). We identified the antigen molecule for 9F5: the 50- to 70-kDa fragments of rat glycoprotein nonmetastatic melanoma protein B (GPNMB)/osteoactivin, which started at Lys(170) . In addition, 9F5 immunoreactivity with GPNMB depended on the activity of furin-like protease(s). More important, rat type 1 MG expressed the GPNMB fragments, but type 2 MG and Mφ did not, although all these cells expressed mRNA and the full-length protein for GPNMB. These results suggest that 9F5 reactivity with MG depends greatly on cleavage of GPNMB and that type 1 MG, in contrast to type 2 MG and Mφ, may have furin-like protease(s) for GPNMB cleavage. In neonatal rat brain, amoeboid 9F5+ MG were observed in specific brain areas including forebrain subventricular zone, corpus callosum, and retina. Double-immunοstaining with 9F5 antibody and anti-Iba1 antibody, which reacts with MG throughout the CNS, revealed that 9F5+ MG were a portion of Iba1+ MG, suggesting that MG subtype(s) exist in vivo. We propose that 9F5 is a useful tool to discriminate between rat type 1 MG and other subtypes of MG/Mφ and to reveal the role of the GPNMB fragments during developing brain. GLIA 2016;64:1938-1961.

Tumor cell-derived secretory factor downregulates Semaphorin-3a in osteoblasts by activating mammalian target of rapamycin pathway

We found that conditioned medium derived from Lewis Lung Carcinoma cells down-regulated Semaphorin3a (Sema3a) mRNA expression and increased the activity of mammalian target of rapamycin complex 1 (mTORC1) in osteoblast-like MC3T3-E1 cells. Furthermore, mTORC1 inhibition with rapamycin counteracted the effect of conditioned media on Sema3a mRNA expression. These results suggest that tumor cells decrease Sema3a mRNA expression in osteoblast in an mTORC1-dependent manner.

Gate-Tunable Spin-Charge Conversion and the Role of Spin-Orbit Interaction in Graphene

The small spin-orbit interaction of carbon atoms in graphene promises a long spin diffusion length and the potential to create a spin field-effect transistor. However, for this reason, graphene was largely overlooked as a possible spin-charge conversion material. We report electric gate tuning of the spin-charge conversion voltage signal in single-layer graphene. Using spin pumping from an yttrium iron garnet ferrimagnetic insulator and ionic liquid top gate, we determined that the inverse spin Hall effect is the dominant spin-charge conversion mechanism in single-layer graphene. From the gate dependence of the electromotive force we showed the dominance of the intrinsic over Rashba spin-orbit interaction, a long-standing question in graphene research.

Abstract 5420: Ribosomal protein-p53-MDM2 signaling by nucleolar stress response and drug discovery

Ribosomal biogenesis is a major energy consuming cellular step, and tightly regulated by the demand of protein synthesis associated with cell growth and proliferation. Thus, defects that impair ribosomal biogenesis cause nucleolar stress response. This response initiates a cascade mediated by ribosomal proteins (RPs), particularly RPL5, RPL11, RPL23, and RPS7. These RPs are usually located in the nucleolus but are rapidly released into the nucleoplasm upon nucleolar stress, activating the tumor suppressor MDM2-p53 pathway. Thus, nucleolar stress response is considered as a quality control surveillance mechanism that regulates balance between proper protein synthesis and cell cycle progression for tumor suppression. However, it is unknown whether there are direct connections between p53-activating RP genes and cancer development in vivo, and whether this stress response might be target for cancer therapy.

We identified nucleolar protein PICT1 as a novel key regulator of nucleolar stress response. To clarify PICT1 function, we generated PICT1-deficient mice and ES cells and carried out extensive analyses. Our results show that even without DNA damage, PICT1 loss results in p53-dependent growth arrest in vitro and in vivo. We further show that PICT1 binds to RPL11, and that RPL11 is released from nucleoli in the absence of PICT1. In PICT1-deficient cells, increased binding of RPL11 to MDM2 blocks MDM2-mediated ubiquitination of p53, leading to p53 accumulation and repression of cell proliferation. Human colon and esophageal cancer patients with low PICT1 expression have better prognoses. Similarly, when shRNA is used to deplete PICT1 in various tumor cell lines with intact p53 signaling, the cells slow in growth and accumulate p53. These data suggest that PICT1 is a novel key regulator of the MDM2-p53 pathway on nucleolar stress response and promotes tumor progression by retaining RPL11 in the nucleolus. Thus, the nucleolar stress response PICT1 regulates could play a definitive role in tumor suppression and, chemicals which induce nucleolar stress response might be lead to new cancer therapeutics.

Therefore, we next constructed a reporter system to visualize and quantitate nucleolar stress response. We found that this reporter system allowed quantitative measurement depend on strength and duration of this stress. As this reporter system showed excellent accuracy, we next screened 400 inhibitors, 1,300 approved drug, and hundreds of natural products from marine species. We found hit compounds including RNA synthesis inhibitor Doxorubicin and Aclarubicin, and also positive control compound, ActinomycinD. In addition, inhibitors of CDK and HDAC were included here. Thus, the nucleolar stress reporter system may reveal unexpected physiological functions of the nucleolar stress response, such as mitotic progression and epigenetics regulation, and identify novel cancer therapeutics, especially for individuals with intact-p53 signaling.

Citation Format: Kohichi Kawahara, Takuto Kawahata, Fumito Horikuchi, Yohei Kamijo, Masatatsu Yamamoto, Yoshinari Shinsato, Kentaro Minami, Kazunari Arima, Toshiyuki Hamada, Tatsuhiko Furukawa. Ribosomal protein-p53-MDM2 signaling by nucleolar stress response and drug discovery. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 5420. doi:10.1158/1538-7445.AM2015-5420

Cooperative therapeutic action of retinoic acid receptor and retinoid x receptor agonists in a mouse model of Alzheimer's disease

Alzheimer's disease (AD) is a neurodegenerative process involving amyloid-β (Aβ) peptide deposition, neuroinflammation, and progressive memory loss. Here, we evaluated whether oral administration of retinoic acid receptor (RAR)α,β agonist Am80 (tamibarotene) or specific retinoid X receptor (RXR) pan agonist HX630 or their combination could improve deficits in an AD model, 8.5-month-old amyloid-β protein precursor 23 (AβPP23) mice. Co-administration of Am80 (0.5 mg/kg) and HX630 (5 mg/kg) for 17 days significantly improved memory deficits (Morris water maze) in AβPP23 mice, whereas administration of either agent alone produced no effect. Only co-administration significantly reduced the level of insoluble Aβ peptide in the brain. These results thus indicate that effective memory improvement via reduction of insoluble Aβ peptide in 8.5-month-old AβPP23 mice requires co-activation of RARα,β and RXRs. RARα-positive microglia accumulated Aβ plaques in the AβPP23 mice. Rat primary microglia co-treated with Am80/HX630 showed increased degradation activity towards 125I-labeled oligomeric Aβ1-42 peptide in an insulin-degrading enzyme (IDE)-dependent manner. The co-administration increased mRNA for IDE and membrane-associated IDE protein in vivo, suggesting that IDE contributes to Aβ clearance in Am80/HX630-treated AβPP23 mice. Am80/HX630 also increased IL-4Rα expression in microglial MG5 cells. The improvement in memory of Am80/HX630-treated AβPP23 mice was correlated with the levels and signaling of hippocampal interleukin-4 (IL-4). Therefore, Am80/HX630 may promote differentiation of IL-4-responsive M2-like microglia and increase their activity for clearance of oligomeric Aβ peptides by restoring impaired IL-4 signaling in AβPP23 mice. Combination treatment with RAR and RXR agonists may be an effective approach for AD therapy.

Nucleolar stress induces ubiquitination-independent proteasomal degradation of PICT1 protein

The nucleolar protein PICT1 regulates tumor suppressor p53 by tethering ribosomal protein L11 within the nucleolus to repress the binding of L11 to the E3 ligase MDM2. PICT1 depletion results in the release of L11 to the nucleoplasm to inhibit MDM2, leading to p53 activation. Here, we demonstrate that nucleolar stress induces proteasome-mediated degradation of PICT1 in a ubiquitin-independent manner. Treatment of H1299 cells with nucleolar stress inducers, such as actinomycin D, 5-fluorouridine, or doxorubicin, induced the degradation of PICT1 protein. The proteasome inhibitors MG132, lactacystin, and epoxomicin blocked PICT1 degradation, whereas the inhibition of E1 ubiquitin-activating enzyme by a specific inhibitor and genetic inactivation fail to repress PICT1 degradation. In addition, the 20 S proteasome was able to degrade purified PICT1 protein in vitro. We also found a PICT1 mutant showing nucleoplasmic localization did not undergo nucleolar stress-induced degradation, although the same mutant underwent in vitro degradation by the 20 S proteasome, suggesting that nucleolar localization is indispensable for the stress-induced PICT1 degradation. These results suggest that PICT1 employs atypical proteasome-mediated degradation machinery to sense nucleolar stress within the nucleolus.

Reduction of MLH1 and PMS2 confers temozolomide resistance and is associated with recurrence of glioblastoma

Although there is a relationship between DNA repair deficiency and temozolomide (TMZ) resistance in glioblastoma (GBM), it remains unclear which molecule is associated with GBM recurrence. We isolated three TMZ-resistant human GBM cell lines and examined the expression of O⁶-methylguanine-DNA methyltransferase (MGMT) and mismatch repair (MMR) components. We used immunohistochemical analysis to compare MutL homolog 1 (MLH1), postmeiotic segregation increased 2 (PMS2) and MGMT expression in primary and recurrent GBM specimens obtained from GBM patients during TMZ treatment. We found a reduction in MLH1 expression and a subsequent reduction in PMS2 protein levels in TMZ-resistant cells. Furthermore, MLH1 or PMS2 knockdown confered TMZ resistance. In recurrent GBM tumours, the expression of MLH1 and PMS2 was reduced when compared to primary tumours.

Prostaglandin E2-induced inflammation: Relevance of prostaglandin E receptors

Prostaglandin E2 (PGE2) is one of the most typical lipid mediators produced from arachidonic acid (AA) by cyclooxygenase (COX) as the rate-limiting enzyme, and acts on four kinds of receptor subtypes (EP1-EP4) to elicit its diverse actions including pyrexia, pain sensation, and inflammation. Recently, the molecular mechanisms underlying the PGE2 actions mediated by each EP subtype have been elucidated by studies using mice deficient in each EP subtype as well as several compounds highly selective to each EP subtype, and their findings now enable us to discuss how PGE2 initiates and exacerbates inflammation at the molecular level. Here, we review the recent advances in PGE2 receptor research by focusing on the activation of mast cells via the EP3 receptor and the control of helper T cells via the EP2/4 receptor, which are the molecular mechanisms involved in PGE2-induced inflammation that had been unknown for many years. We also discuss the roles of PGE2 in acute inflammation and inflammatory disorders, and the usefulness of anti-inflammatory therapies that target EP receptors. This article is part of a Special Issue entitled "Oxygenated metabolism of PUFA: analysis and biological relevance".

PICT1 expression is a poor prognostic factor in non-small cell lung cancer

PICT1 is a key regulator of the MDM2–TP53 pathway. High mRNA expression levels of PICT1 are associated with poor prognosis in several cancers with wild-type TP53. In this study, we identified the PICT1 protein expression profile in non-small cell lung cancer (NSCLC) with wild-type TP53 in the nucleolus and cytoplasm, and revealed the relationship between PICT1 expression and patient clinicopathological factors. PICT1 expression in the tumor cells of 96 NSCLC patients with wild-type TP53 was evaluated by immunohistochemistry. Forty-three of 96 (44.8%) NSCLC samples were positive for nucleolar PICT1, while 40/96 (41.7%) NSCLC samples were positive for cytoplasmic PICT1. There was no correlation between nucleolar PICT1 expression and clinicopathological factors. However, cytoplasmic PICT1 expression was significantly correlated with sex, smoking history, differentiation, lymphatic invasion and pathological stage. In multivariate analysis, lymphatic invasion was significantly associated with cytoplasmic PICT1 expression (hazard ratio: 5.02, P = 0.026). We scrutinized PICT1 expression in samples of NSCLC with wild-type TP53, and showed a correlation between cytoplasmic PICT1 expression and several clinicopathological factors in these patients. Our results indicate that cytoplasmic PICT1 expression is a poor prognostic factor and is associated with tumor progression via lymphatic invasion in these patients.

Upregulation of non-β cell-derived vascular endothelial growth factor A increases small clusters of insulin-producing cells in the pancreas

Pancreatic β cell-derived vascular endothelial growth factor A (VEGF-A) contributes to normal β cell function. We therefore hypothesized that non-β cell-derived VEGF-A may affect its properties in adult mice.We generated transgenic mice expressing human VEGF-A (hVEGF-A) in a visceral smooth muscle cell (SMC)-dominant manner under the control of the transgelin (Tagln/SM22α) promoter via a tamoxifen-induced Cre/loxP recombination system (SM-CreER(T2)/hVEGF mice).SM-CreER(T2)/hVEGF mice received tamoxifen orally followed by microscopic examination of their pancreas 4 weeks after the hVEGF-A induction. The number of clusters of insulin-producing cells (IPCs) in islets, pancreatic ducts, and individual IPCs were counted.The number of small IPC clusters (100-215 μm(2)) in the pancreas increased significantly in SM-CreER(T2)/hVEGF mice compared with SM-CreER(T2)(Ki) mice (473 out of 1 992 counts vs. 199 out of 976 counts, p<0.05), although total IPC area and the number of pancreatic duct IPCs, in proportion to exocrine area, were similar between the 2 groups. Although most small IPC clusters observed in SM-CreER(T2)/hVEGF mice were not accompanied by α and/or δ cells, some were attached to a single or a few α cells. An STZ-induced diabetic state in SM-CreER(T2)/hVEGF mice was slightly ameliorated, with only one point of significance 12 weeks after STZ administration, compared with SM-CreER(T2)(Ki) mice.Upregulation of non-β cell-derived VEGF-A may alter the composition of pancreatic IPCs by increasing the number of small IPC clusters. These findings provide new information on the role of non-β cell-derived VEGF-A to IPC regeneration and insulin production.

Comprehensive safety management and assessment at rugby football competitions

The present study aims to improve medical systems by designing objective safety assessment criteria for rugby competitions. We evaluated 195 competitions between 2002 and 2011 using an original safety scale comprising the following sections: 1) competence of staff such as referees, medical attendants and match day doctor; 2) environment such as weather, wet bulb globe temperature and field conditions; and 3) emergency medical care systems at the competitions. Each section was subdivided into groups A, B and C according to good, normal or fair degrees of safety determined by combinations of the results.Overall safety was assessed as A, B and C for 110, 78 and 7 competitions, respectively. The assessments of individual major factors were mostly favorable for staff, but the environment and medical care systems were assessed as C in 25 and 70, respectively, of the 195 competitions. Medical management involves not having a match day doctor, but also comprehensive management including preventive factors and responses from the staff, environment and medical-care systems. 6 cases of severe injuries and accidents occurred between 2002 and 2011, which were observed in Grade A competition. These cases revealed better prognosis without obvious impairment, thus confirming the value of the present assessment scale.