ABCC4 suppresses glioblastoma progression and recurrence by restraining cGMP-PKG signalling.

BACKGROUND: Cyclic nucleotides are critical mediators of cellular signalling in glioblastoma. However, the clinical relevance and mechanisms of regulating cyclic nucleotides in glioblastoma progression and recurrence have yet to be thoroughly explored. METHODS: In silico, mRNA, and protein level analyses identified the primary regulator of cyclic nucleotides in recurrent human glioblastoma. Lentiviral and pharmacological manipulations examined the functional impact of cyclic nucleotide signalling in human glioma cell lines and primary glioblastoma cells. An orthotopic xenograft mice model coupled with aspirin hydrogels verified the in vivo outcome of targeting cyclic nucleotide signalling. RESULTS: Elevated intracellular levels of cGMP, instead of cAMP, due to a lower substrate efflux from ATP-binding cassette sub-family C member 4 (ABCC4) is engaged in the recurrence of glioblastoma. ABCC4 gene expression is negatively associated with recurrence and overall survival outcomes in glioblastoma specimens. ABCC4 loss-of-function activates cGMP-PKG signalling, promoting malignancy in glioblastoma cells and xenografts. Hydrogels loaded with aspirin, inhibiting glioblastoma progression partly by upregulating ABCC4 expressions, augment the efficacy of standard-of-care therapies in orthotopic glioblastoma xenografts. CONCLUSION: ABCC4, repressing the cGMP-PKG signalling pathway, is a tumour suppressor in glioblastoma progression and recurrence. Aspirin hydrogels impede glioblastoma progression through ABCC4 restoration and constitute a viable translational approach.

Cellular and exosomal GPx1 are essential for controlling hydrogen peroxide balance and alleviating oxidative stress in hypoxic glioblastoma.

Tumor hypoxia promotes malignant progression and therapeutic resistance in glioblastoma partly by increasing the production of hydrogen peroxide (H2O2), a type of reactive oxygen species critical for cell metabolic responses due to its additional role as a second messenger. However, the catabolic pathways that prevent H2O2 overload and subsequent tumor cell damage in hypoxic glioblastoma remain unclear. Herein, we present a hypoxia-coordinated H2O2 regulatory mechanism whereby excess H2O2 in glioblastoma induced by hypoxia is diminished by glutathione peroxidase 1 (GPx1), an antioxidant enzyme detoxifying H2O2, via the binding of hypoxia-inducible factor-1α (HIF-1α) to GPx1 promoter. Depletion of GPx1 results in H2O2 overload and apoptosis in glioblastoma cells, as well as growth inhibition in glioblastoma xenografts. Moreover, tumor hypoxia increases exosomal GPx1 expression, which assists glioblastoma and endothelial cells in countering H2O2 or radiation-induced apoptosis in vitro and in vivo. Clinical data explorations further demonstrate that GPx1 expression was positively correlated with tumor grade and expression of HIF-1α, HIF-1α target genes, and exosomal marker genes; by contrast, it was inversely correlated with the overall survival outcome in human glioblastoma specimens. Our analyses validate that the redox balance of H2O2 within hypoxic glioblastoma is clinically relevant and could be maintained by HIF-1α-promoted or exosome-related GPx1.

Hypoxia-induced CXC chemokine ligand 14 expression drives protumorigenic effects through activation of insulin-like growth factor-1 receptor signaling in glioblastoma.

Hypoxic tumor microenvironment (HTM) promotes a more aggressive and malignant state in glioblastoma. However, little is known about the role and mechanism of CXC chemokine ligand 14 (CXCL14) in HTM-mediated glioblastoma progression. In this study, we report that CXCL14 expression correlated with poor outcomes, tumor grade, and hypoxia-inducible factor (HIF) expression in patients with glioblastoma. CXCL14 was upregulated in tumor cells within the hypoxic areas of glioblastoma. Hypoxia induced HIF-dependent expression of CXCL14, which promoted glioblastoma tumorigenicity and invasiveness in vitro and in vivo. Moreover, CXCL14 gain-of-function in glioblastoma cells activated insulin-like growth factor-1 receptor (IGF-1R) signal transduction to regulate the growth, invasiveness, and neurosphere formation of glioblastoma. Finally, systemic delivery of CXCL14 siRNA nanoparticles (NPs) with polysorbate 80 coating significantly suppressed tumor growth in vivo and extended the survival time in patient-derived glioblastoma xenografts. Together, these findings suggest that HIF-dependent CXCL14 expression contributes to HTM-promoted glioblastoma tumorigenicity and invasiveness through activation of the IGF-1R signaling pathway. CXCL14 siRNA NPs as an oligonucleotide drug can inhibit glioblastoma progression and constitute a translational path for the clinical treatment of glioblastoma patients.

Id2 exerts tumor suppressor properties in lung cancer through its effects on cancer cell invasion and migration.

Background: Despite advances in prognosis and treatment of lung adenocarcinoma (LADC), a notable non-small cell lung cancer subtype, patient outcomes are still unsatisfactory. New insight on novel therapeutic strategies for LADC may be gained from a more comprehensive understanding of cancer progression mechanisms. Such strategies could reduce the mortality and morbidity of patients with LADC. In our previous study, we performed cDNA microarray screening and found an inverse relationship between inhibitor of DNA binding 2 (Id2) expression levels and the invasiveness of LADC cells. Materials and Methods: To identify the functional roles of Id2 and its action mechanisms in LADC progression, we successfully established several Id2-overexpressing and Id2-silenced LADC cell clones. Subsequently, we examined in vitro the effects exerted by Id2 on cell morphology, proliferation, colony formation, invasive, and migratory activities and examined in vivo those exerted by Id2 on cell metastasis. The mechanisms underlying the action of Id2 were investigated using RNA-seq and pathway analyses. Furthermore, the correlations of Id2 with its target gene expression and clinical outcomes were calculated. Results: Our data revealed that Id2 overexpression could inhibit LADC cells' migratory, invasive, proliferation, and colony formation capabilities. Silencing Id2 expression in LADC cells reversed the aforementioned inhibitory effects, and knockdown of Id2 increased LADC cells' metastatic abilities in vivo. Bioinformatics analysis revealed that these effects of Id2 on cancer progression might be regulated by focal adhesion kinase (FAK) signaling and CD44/Twist expression. Furthermore, in online clinical database analysis, patients with LADC whose Id2 expression levels were high and FAK/Twist expression levels were low had superior clinical outcomes.Conclusion: Our data indicate that the Id2 gene may act as a metastasis suppressor and provide new insights into LADC progression and therapy.

Haloperidol Instigates Endometrial Carcinogenesis and Cancer Progression by the NF-κB/CSF-1 Signaling Cascade.

Haloperidol is a routine drug for schizophrenia and palliative care of cancer; it also has antitumor effects in several types of cancer. However, the role of haloperidol in endometrial cancer (EC) development is still unclear. Here, we show that chronic haloperidol treatment in clinically relevant doses induced endometrial hyperplasia in normal mice and promoted tumor growth and malignancy in mice with orthotopic EC. The pharmacokinetic study indicated that haloperidol highly accumulated in the uterus of mice. In vitro studies revealed that haloperidol stimulated the cellular transformation of human endometrial epithelial cells (HECCs) and promoted the proliferation, migration, and invasion of human endometrial carcinoma cells (HECCs) by activating nuclear factor kappa B (NF-κB) and its downstream signaling target, colony-stimulating factor 1 (CSF-1). Gain of function of CSF-1 promotes the cellular transformation of HEECs and the malignant progression of HECCs. Moreover, blockade of CSF-1 inhibited haloperidol-promoted EC progression in vitro and in vivo. A population-based cohort study of EC patients further demonstrated that the use of haloperidol was associated with increased EC-specific mortality. Collectively, these findings indicate that clinical use of haloperidol could potentially be harmful to female patients with EC.

Coriloxin Exerts Antitumor Effects in Human Lung Adenocarcinoma Cells.

Both in Taiwan and around the world, lung cancer is a primary cause of cancer-related deaths. In Taiwan, the most prevalent form of lung cancer is lung adenocarcinoma, a type of non-small-cell lung carcinoma. Although numerous lung cancer therapies are available, their clinical outcomes are unsatisfactory. Natural products, including fungal metabolites, are excellent sources of pharmaceutical compounds used in cancer treatment. We employed in vitro cell invasion, cell proliferation, cell migration, cell viability, and colony formation assays with the aim of evaluating the effects of coriloxin, isolated from fermented broths of Nectria balsamea YMJ94052402, on human lung adenocarcinoma CL1-5 and/or A549 cells. The potential targets regulated by coriloxin were examined through Western blot analysis. The cytotoxic effect of coriloxin was more efficiently exerted on lung adenocarcinoma cells than on bronchial epithelial cells. Moreover, low-concentration coriloxin significantly suppressed adenocarcinoma cells' proliferative, migratory, and clonogenic abilities. These inhibitory effects were achieved through ERK/AKT inactivation, epithelial-mesenchymal transition regulation, and HLJ1 expression. Our findings suggest that coriloxin can be used as a multitarget anticancer agent. Further investigations of the application of coriloxin as an adjuvant therapy in lung cancer treatment are warranted.

Paired-like homeodomain 2B contributes to tumour progression and anti-autophagy in human lung cancer.

Paired-like homeodomain transcription factor 2 (PITX2) is well known to play an essential role in normal embryonic development. Emerging evidence suggests that PITX2 may be involved in human tumorigenesis, but the role of PITX2 in tumour progression remains largely unclear. The expression levels of PITX2 in lung cancer cells were determined by qRT-PCR and Western blot analyses. Gain- and loss-of-function experiments were conducted to investigate the biological roles of PITX2 in the phenotype of lung cancer cells. Immunofluorescence staining and transmission electron microscopy were used to observe autophagy. The expression level and clinical significance of PITX2 were determined in a Taiwanese cohort and the Gene Expression Omnibus (GEO) database, respectively. Here, we show that PITX2B is the most abundant isoform of the bicoid homeodomain family in lung cancer cells. The enforced expression of PITX2B promoted lung cancer tumorigenesis and progression in vitro and in vivo. The mechanistic analysis revealed that the nuclear localization of PITX2B is correlated with its oncogenic functions and two important nuclear localization signals. In addition, PITX2B knockdown in lung cancer cells caused a marked increase in autophagy and apoptosis, suggesting that PITX2B plays an important role in lung cancer cell survival. Moreover, a high expression of PITX2B was associated with a poor overall survival (P<0.05) in both Taiwanese non-small-cell lung cancer patients and GEO lung cancer cohorts. These results provide new insight into the contribution of PITX2B to lung cancer progression, implicate PITX2B as an important component of cell survival signals and further establish PITX2B as a therapeutic target for lung cancer treatment.

Preparation of Catechin Nanoemulsion from Oolong Tea Leaf Waste and Its Inhibition of Prostate Cancer Cells DU-145 and Tumors in Mice.

Anti-cancer activity of catechin nanoemulsions prepared from Oolong tea leaf waste was studied on prostate cancer cells DU-145 and DU-145-induced tumors in mice. Catechin nanoemulsions composed of lecithin, Tween-80 and water in an appropriate proportion was prepared with high stability, particle size of 11.3 nm, zeta potential of -67.2 mV and encapsulation efficiency of 83.4%. Catechin nanoemulsions were more effective than extracts in inhibiting DU-145 cell growth, with the IC50 being 13.52 and 214.6 µg/mL, respectively, after 48 h incubation. Furthermore, both catechin nanoemulsions and extracts could raise caspase-8, caspase-9 and caspase-3 activities for DU-145 cell apoptosis, arresting the cell cycle at S and G2/M phases. Compared to control, catechin nanoemulsion at 20 µg/mL and paclitaxel at 10 µg/mL were the most effective in reducing tumor volume by 41.3% and 52.5% and tumor weight by 77.5% and 90.6% in mice, respectively, through a decrease in EGF and VEGF levels in serum.

Prognostic value and prevalence of complete right bundle branch block in an elderly population: a community-based 10-year prospective study.

Complete right bundle branch block (CRBBB) occurs in 0.2% to 1.3% of the general population, but its prognostic significance in the geriatric population is unknown. We prospectively investigated the prevalence and prognostic value of CRBBB in individuals aged ≥65 years in a community-based population in Taiwan. A total of 5,830 community-dwelling individuals were prospectively recruited from 7 regions across Taiwan starting in December 2008 through March 2013. Those aged ≥65 years were included in the analysis (N=3,383). All subjects underwent a home visit and standardized medical exams and were followed up annually until the end of April 2019; cause of death was documented by citizen death records. The mean age of the study cohort was 73.5±5.9 years (65-104), and 47.21% were men. Among these individuals, 171 (5.05%) had CRBBB; the prevalence was higher in men (7.08%) than in women (3.25%). Subjects with CRBBB were older than those without CRBBB (75.4±6.5 vs. 73.4±5.9), and the frequency of CRBBB increased with age. Survival analysis revealed that all-cause mortality and cardiac mortality were similar in individuals with and without CRBBB during a mean follow-up of 92.6±23.6 months. CRBBB is not associated with increased risk of mortality in the geriatric population.

The 10-Year Prognosis and Prevalence of Brugada-Type Electrocardiograms in Elderly Women: A Longitudinal Nationwide Community-Based Prospective Study.

BACKGROUND: Brugada syndrome is a disorder associated with sudden cardiac death and characterized by an abnormal electrocardiogram (ECG). Previous studies were predominantly conducted in men, and the data on long-term prognosis are limited. Information about women, especially elderly women, is lacking. OBJECTIVE: The aim of this study was to investigate the long-term prognosis of the Brugada ECG pattern in elderly women. METHOD: We investigated the 10-year prognosis of the Brugada ECG pattern in elderly women in a nationwide community-based population in Taiwan. Community-dwelling women older than 55 years were prospectively recruited from December 2008 to March 2013 by a stratified random sampling method. All enrolled individuals were followed up annually until April 2019, and the cause of death was documented by citizen death records. RESULTS: Among 2597 women, 60 (2.31%) had a Brugada-type ECG, and this prevalence was higher than the mean global prevalence of 0.23%. One woman had a type 1 ECG (0.04%), whereas 15 (0.58%) and 44 (1.70%) women had type 2 and type 3 ECG patterns, respectively. Cox survival analysis revealed that all-cause mortality and cardiac mortality were similar in the individuals with and without a Brugada-type ECG during a mean follow-up of 96.1 ± 20.5 months. CONCLUSIONS: Our findings suggest that Brugada ECG patterns are not infrequent in elderly women but are not associated with increased risk of mortality in long-term follow-up; these findings may help reduce unnecessary anxiety for physicians, nurses, allied health caregivers, and patients.

Anticancer effects of epigallocatechin-3-gallate nanoemulsion on lung cancer cells through the activation of AMP-activated protein kinase signaling pathway.

Epigallocatechin-3-gallate (EGCG), a green tea-derived polyphenol, exhibits antitumor activities. An EGCG nanoemulsion (nano-EGCG) was prepared to improve the stability and reduce the side effects of EGCG for treatment of human lung cancer cells, and the antitumor effects were studied. The possible molecular mechanism underlying its antitumor effects on cultured human lung cancer cells was also elucidated. The antitumor effects of EGCG and nano-EGCG were determined using methylthiazolyldiphenyl-tetrazolium bromide (MTT), colony formation, migration, and invasion assays. In addition, changes in the AMP-activated protein kinase (AMPK) signaling pathway were investigated using Western blot analyses. AMPK inhibitors were used to determine the roles of the AMPK signaling pathway involved in the molecular mechanism of the nano-EGCG. Our results showed that both EGCG and nano-EGCG inhibited the growth of H1299 lung cancer cells, with half-maximal inhibitory concentrations of 36.03 and 4.71 µM, respectively. Additionally, nano-EGCG effectively suppressed lung cancer cell colony formation, migration, and invasion in a dose-dependent manner. Nano-EGCG may inhibit lung cancer cell invasion through matrix metalloproteinase (MMP)-2- and MMP-9-independent mechanisms. Furthermore, the expression of several key regulatory proteins in the AMPK signaling pathway was modulated by nano-EGCG. Nano-EGCG may inhibit lung cancer cell proliferation, colony formation, migration, and invasion through the activation of AMPK signaling pathways. This novel mechanism of nano-EGCG suggests its application in lung cancer prevention and treatment. Our results provide an experimental foundation for further research on its potential activities and effects in vivo.

Inhibitor of DNA-Binding Protein 4 Suppresses Cancer Metastasis through the Regulation of Epithelial Mesenchymal Transition in Lung Adenocarcinoma.

Metastasis is a predominant cause of cancer death and the major challenge in treating lung adenocarcinoma (LADC). Therefore, exploring new metastasis-related genes and their action mechanisms may provide new insights for developing a new combative approach to treat lung cancer. Previously, our research team discovered that the expression of the inhibitor of DNA binding 4 (Id4) was inversely related to cell invasiveness in LADC cells by cDNA microarray screening. However, the functional role of Id4 and its mechanism of action in lung cancer metastasis remain unclear. In this study, we report that the expression of Id4 could attenuate cell migration and invasion in vitro and cancer metastasis in vivo. Detailed analyses indicated that Id4 could promote E-cadherin expression through the binding of Slug, cause the occurrence of mesenchymal-epithelial transition (MET), and inhibit cancer metastasis. Moreover, the examination of the gene expression database (GSE31210) also revealed that high-level expression of Id4/E-cadherin and low-level expression of Slug were associated with a better clinical outcome in LADC patients. In summary, Id4 may act as a metastatic suppressor, which could not only be used as an independent predictor but also serve as a potential therapeutic for LADC treatment.

Antioxidant property of Taraxacum formosanum Kitam and its antitumor activity in non-small-cell lung cancer cells.

BACKGROUND: Non-small-cell lung cancer (NSCLC) is known to exhibit resistance to various therapeutic agents and become progressively incurable. Taraxacum formosanum is a medicinal Chinese herb that has been clinically used in Taiwan. However, the investigations of the effects of whole plant on lung cancer are limited. PURPOSE: This study evaluated the in vitro antioxidant, antiproliferative, and antimigration effects of the ethanol extract of T. formosanum (ETF). The possible molecular mechanism underlying its antitumor effects on cultured human NSCLC cell lines was also elucidated. METHODS: The antioxidant effects of the ETF were determined using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and Trolox equivalent antioxidant capacity (TEAC) assays, and its antiproliferative and antimigration effects were determined using trypan blue exclusion and wound healing assays, respectively. In addition, changes in the mitogen-activated protein kinase (MAPK) signaling pathway were investigated using Western blot analyses. Various inhibitors were used to determine the roles of the MAPK signaling pathway involved in the molecular mechanism of the ETF. RESULTS: Our results showed that the ETF exhibited strong reducing power, a high Trolox equivalent antioxidant capacity (TEAC) value, and potent 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging and Fe+2-chelating abilities. The ETF also exerted antiproliferative and antimigration effects on NSCLC cells in a dose-dependent manner. These effects may be mediated by the inhibitory effects of the ETF on the activation of extracellular signal-regulated kinase. CONCLUSIONS: This study performed the first pharmacological exploration of T. formosanum. Our results demonstrated the antioxidant and antitumor effects of the ETF on NSCLC cell lines, indicating their potential preventive and therapeutic values for lung cancer.

HOXA5 and p53 cooperate to suppress lung cancer cell invasion and serve as good prognostic factors in non-small cell lung cancer.

Lung cancer is the leading cause of cancer mortality worldwide and tumor metastasis is the major cause of cancer-related death. Our previous study suggested that Homeobox A5 (HOXA5) could inhibit lung cancer cell invasion via regulating cytoskeletal remodeling and involved in tumor metastasis. Recently, consensus HOX binding sites was found in the p53 gene promoter region. However, whether the HOXA5 could cooperate with p53 and contribute the inhibition of lung cancer cell invasion is still unclear. The aim of the current study is to elucidate the correlation of HOXA5 and p53 in tumor invasion and its prognostic influence in lung cancer patient specimens. Totally 71 cases of primary non-small cell lung cancer (NSCLC) were collected. The median follow-up period is 6.8 years. Immunohistochemical stain for p53 and HOXA5 were performed. Kaplan-Meier plot was done for overall survival analysis. In addition, lung cancer cell lines transfected with wild-type or mutated p53 constructs were overexpressed with HOXA5 for invasion assay. In human specimens, HOXA5 expressed mainly in the cytoplasm (54.1%) rather than nuclei (14.6%) of the NSCLC tumor part. The HOXA5 expression is higher in adenocarcinoma than in squamous cell carcinoma (P < 0.001). In addition, poor prognosis is seen in group with both non-immunoreactive for p53 and HOXA5. HOXA5 and p53 could cooperate to inhibit tumor cell invasion significantly partly by decreasing MMP2 activity in a concentration-dependent manner. Our studies provide new insights into how HOXA5 and p53 cooperate to contribute to the suppression of lung cancer cell invasion and play good prognostic roles in NSCLC.

Tumor Hypoxia Regulates Forkhead Box C1 to Promote Lung Cancer Progression.

Forkhead box C1 (FOXC1) is a member of the forkhead family of transcription factors that are characterized by a DNA-binding forkhead domain. Increasing evidence indicates that FOXC1 is involved in tumor progression. However, the role of tumor hypoxia in FOXC1 regulation and its impact on lung cancer progression are unclear. Here, we report that FOXC1 was upregulated in hypoxic areas of lung cancer tissues from rodents or humans. Hypoxic stresses significantly induced FOXC1 expression. Moreover, hypoxia activated FOXC1 transcription via direct binding of hypoxia-inducible factor-1α (HIF-1α) to the hypoxia-responsive element (HRE) in the FOXC1 promoter. FOXC1 gain-of-function in lung cancer cells promoted cell proliferation, migration, invasion, angiogenesis, and epithelial-mesenchymal transition in vitro. However, a knockdown of FOXC1 in lung cancer cells inhibited these effects. Notably, knockdown of tumor hypoxia-induced FOXC1 expression via HIF-1-mediated FOXC1 shRNAs in lung cancer xenograft models suppressed tumor growth and angiogenesis. Finally, systemic delivery of FOXC1 siRNA encapsulated in lipid nanoparticles inhibited tumor growth and increased survival time in lung cancer-bearing mice. Taken together, these data indicate that FOXC1 is a novel hypoxia-induced transcription factor and plays a critical role in tumor microenvironment-promoted lung cancer progression. Systemic FOXC1 blockade therapy may be an effective therapeutic strategy for lung cancer.

Optimizing a Male Reproductive Aging Mouse Model by D-Galactose Injection.

The d-galactose (d-gal)-injected animal model, which is typically established by administering consecutive subcutaneous d-gal injections to animals for approximately six or eight weeks, has been frequently used for aging research. In addition, this animal model has been demonstrated to accelerate aging in the brain, kidneys, liver and blood cells. However, studies on aging in male reproductive organs that have used this animal model remain few. Therefore, the current study aimed to optimize a model of male reproductive aging by administering d-gal injections to male mice and to determine the possible mechanism expediting senescence processes during spermatogenesis. In this study, C57Bl/6 mice were randomized into five groups (each containing 8-10 mice according to the daily intraperitoneal injection of vehicle control or 100 or 200 mg/kg dosages of d-gal for a period of six or eight weeks). First, mice subjected to d-gal injections for six or eight weeks demonstrated considerably decreased superoxide dismutase activity in the serum and testis lysates compared to those in the control group. The lipid peroxidation in testis also increased in the d-gal-injected groups. Furthermore, the d-gal-injected groups exhibited a decreased ratio of testis weight/body weight and sperm count compared to the control group. The percentages of both immotile sperm and abnormal sperm increased considerably in the d-gal-injected groups compared to those of the control group. To determine the genes influenced by the d-gal injection during murine spermatogenesis, a c-DNA microarray was conducted to compare testicular RNA samples between the treated groups and the control group. The d-gal-injected groups exhibited RNA transcripts of nine spermatogenesis-related genes (Cycl2, Hk1, Pltp, Utp3, Cabyr, Zpbp2, Speer2, Csnka2ip and Katnb1) that were up- or down-regulated by at least two-fold compared to the control group. Several of these genes are critical for forming sperm-head morphologies or maintaining nuclear integration (e.g., cylicin, basic protein of sperm head cytoskeleton 2 (Cylc2), casein kinase 2, alpha prime interacting protein (Csnka2ip) and katanin p80 (WD40-containing) subunit B1 (Katnb1)). These results indicate that d-gal-injected mice are suitable for investigating male reproductive aging.

Cycling hypoxia induces chemoresistance through the activation of reactive oxygen species-mediated B-cell lymphoma extra-long pathway in glioblastoma multiforme.

BACKGROUND: Cycling hypoxia is a well-recognized phenomenon within animal and human solid tumors. It contributes to the resistance to cytotoxic therapies through anti-apoptotic effects. However, the mechanism underlying cycling hypoxia-mediated anti-apoptosis remains unclear. METHODS: Reactive oxygen species (ROS) production, activation of the hypoxia-inducible factor-1 alpha (HIF-1α) and nuclear factor-κB (NF-κB) signaling pathways, B-cell lymphoma extra-long (Bcl-xL) expression, caspase activation, and apoptosis in in vitro hypoxic stress-treated glioblastoma cells or tumor hypoxic cells derived from human glioblastoma xenografts were determined by in vitro ROS analysis, reporter assay, western blotting analysis, quantitative real-time PCR, caspase-3 activity assay, and annexin V staining assay, respectively. Tempol, a membrane-permeable radical scavenger, Bcl-xL knockdown, and specific inhibitors of HIF-1α and NF-κB were utilized to explore the mechanisms of cycling hypoxia-mediated resistance to temozolomide (TMZ) in vitro and in vivo and to identify potential therapeutic targets. RESULTS: Bcl-xL expression and anti-apoptotic effects were upregulated under cycling hypoxia in glioblastoma cells concomitantly with decreased responses to TMZ through ROS-mediated HIF-1α and NF-κB activation. Tempol, YC-1 (HIF-1 inhibitor), and Bay 11-7082 (NF-κB inhibitor) suppressed the cycling hypoxia-mediated Bcl-xL induction in vitro and in vivo. Bcl-xL knockdown and Tempol treatment inhibited cycling hypoxia-induced chemoresistance. Moreover, Tempol treatment of intracerebral glioblastoma-bearing mice combined with TMZ chemotherapy synergistically suppressed tumor growth and increased survival rate. CONCLUSIONS: Cycling hypoxia-induced Bcl-xL expression via ROS-mediated HIF-1α and NF-κB activation plays an important role in the tumor microenvironment-promoted anti-apoptosis and chemoresistance in glioblastoma. Thus, ROS blockage may be an attractive therapeutic strategy for tumor microenvironment-induced chemoresistance.

HOXA5 inhibits metastasis via regulating cytoskeletal remodelling and associates with prolonged survival in non-small-cell lung carcinoma.

Homeobox genes comprise a family of regulatory genes that contain a common homeobox domain and act as transcription factors. Recent studies indicate that homeobox A5 (HOXA5) may serve as a tumour suppressor gene in breast cancers. However, the precise role and the underlying mechanism of HOXA5 in lung cancer remain unclear. Oligonucleotide microarrays and an invasion/metastasis lung adenocarcinoma cell line model were used to determine the correlation between HOXA5 expression and cancer cell invasion ability. We found that ectopic expression of HOXA5 in highly invasive cancer cells suppressed cell migration, invasion, and filopodia formation in vitro and inhibited metastatic potential in vivo. Knockdown of HOXA5 promoted the invasiveness of lung cancer cells. In addition, HOXA5 expression was associated with better clinical outcome in non-small cell lung cancer patients with wild-type EGFR. Furthermore, genome-wide transcriptomic and pathway analyses were performed to identify the potential molecular mechanisms. Our data showed that HOXA5 may bind to the promoters of the cytoskeleton-related genes and downregulate their mRNA and protein expression levels. Our studies provide new insights into how HOXA5 may contribute to the suppression of metastasis in lung cancer via cytoskeleton remodelling regulation. Therefore, targeted induction of HOXA5 may represent a promising approach for non-small-cell lung cancer therapy.

Livin contributes to tumor hypoxia-induced resistance to cytotoxic therapies in glioblastoma multiforme.

PURPOSE: Tumor hypoxia is one of the crucial microenvironments to promote therapy resistance (TR) in glioblastoma multiforme (GBM). Livin, a member of the family of inhibitor of apoptosis proteins, contributes antiapoptosis. However, the role of tumor hypoxia in Livin regulation and its impact on TR are unclear. EXPERIMENTAL DESIGN: Livin expression and apoptosis for tumor hypoxic cells derived from human glioblastoma xenografts or in vitro hypoxic stress-treated glioblastoma cells were determined by Western blotting, immunofluorescence imaging, and annexin V staining assay. The mechanism of hypoxia-induced Livin induction was investigated by chromatin immunoprecipitation assay and reporter assay. Genetic and pharmacologic manipulation of Livin was utilized to investigate the role of Livin on tumor hypoxia-induced TR in vitro or in vivo. RESULTS: The upregulation of Livin expression and downregulation of caspase activity were observed under cycling and chronic hypoxia in glioblastoma cells and xenografts, concomitant with increased TR to ionizing radiation and temozolomide. However, knockdown of Livin inhibited these effects. Moreover, hypoxia activated Livin transcription through the binding of hypoxia-inducible factor-1α to the Livin promoter. The targeted inhibition of Livin by the cell-permeable peptide (TAT-Lp15) in intracerebral glioblastoma-bearing mice demonstrated a synergistic suppression of tumor growth and increased the survival rate in standard-of-care treatment with radiation plus temozolomide. CONCLUSIONS: These findings indicate a novel pathway that links upregulation of Livin to tumor hypoxia-induced TR in GBM and suggest that targeting Livin using cell-permeable peptide may be an effective therapeutic strategy for tumor microenvironment-induced TR.

Prevalence and prognosis of Brugada electrocardiogram patterns in an elderly Han Chinese population: a nation-wide community-based study (HALST cohort).

AIMS: The exact world-wide prevalence of Brugada electrocardiogram (ECG) pattern is still unclear, especially in adults aged 55 years and older. METHODS AND RESULTS: The study was conducted as part of the Healthy Aging Longitudinal Study in Taiwan (HALST). Using a stratified random sampled method, a sample of community-dwelling subjects was recruited from seven community-based regions across Taiwan. All enrolled subjects were follow-up annually and cause of death was documented by citizen death records. A total of 5214 subjects were enrolled (male/female: 2530/2684) with a mean age of 69 ± 8 years. The overall prevalence of Brugada ECG patterns was 3.32%. Four subjects carried spontaneous Type 1 Brugada ECG pattern, 68 carried Type 2, and 101 carried Type 3. Compared with the world-wide average prevalence of Brugada ECG patterns, the prevalence of spontaneous Type 1 Brugada ECG pattern in subjects from the HALST cohort was similar (0.077 vs. 0.07%) and the combined prevalence of Types 2 and 3 Brugada ECG pattern was 10 times higher (3.24 vs. 0.28%) even the mean age of study subjects was significantly higher (69 ± 8 vs. 35 ± 8, P < 0.001). However, all-cause mortality and cardiac mortality rates were not significantly different between subjects with and without Brugada ECG patterns during the 4-year follow-up (log-rank test, P = 0.21, 0.32, respectively). CONCLUSION: The prevalence of Brugada ECG pattern in adults aged 55 years and older in Taiwan was higher than the average world-wide prevalence but was not associated with increased mortality.