ARHGAP10, downregulated in ovarian cancer, suppresses tumorigenicity of ovarian cancer cells

Rho GTPase-activating proteins (RhoGAPs) are implicated in the development and progression of ovarian cancer. ARHGAP10 is a member of RhoGAP proteins and inactivates Cdc42 by converting GTP-bound form to GDP-bound form. Here, we aimed to evaluate ARHGAP10 expression profile and functions in ovarian cancer. The decreased expression of ARHGAP10 was found in 77.3% (58/75) of ovarian cancer tissues, compared with their non-tumorous counterparts. Furthermore, overall survival in ovarian cancer patients with higher expression of ARHGAP10 was longer than those with lower expression. Ectopic expression of ARHGAP10 in two ovarian cancer cell lines with lower expression of ARHGAP10 (A2780 and HO-8910) dramatically suppressed cell proliferation in vitro. In nude mice, its stable overexpression significantly inhibited the tumorigenicity of A2780 cells. We further demonstrated that overexpression of ARHGAP10 significantly inhibited cell adhesion, migration and invasion, resulted in cell arrest in G1 phase of cell cycle and a significant increase of apoptosis. Moreover, ARHGAP10 interacted with Cdc42 and overexpression of ARHGAP10 inhibited the activity of Cdc42 in A2780 cells. Gene set enrichment analysis on The Cancer Genome Atlas dataset showed that KEGG cell cycle, replication and base excision repair (BER) pathways were correlatively with the ARHGAP10 expression, which was further confirmed in ovarian cancer cells by western blotting. Hence, ARHGAP10 may serve as a tumor suppressor through inactivating Cdc42, as well as inhibiting cell cycle, replication and BER pathways. Our data suggest an important role of ARHGAP10 in the molecular etiology of cancer and implicate the potential application of ARHGAP10 in cancer therapy.

Do Chinese have similar health-state preferences? A comparison of mainland Chinese and Singaporean Chinese

BACKGROUND

Little is known about whether health-state preferences differ among Chinese populations. This study compared the preference values for EQ-5D-5L health states between mainland Chinese and Singaporean Chinese.

METHODS

The preference values for ten EQ-5D-5L health states were elicited from general population samples of mainland Chinese and Singaporeans. In computer-assisted self-interviews, each participant completed five time trade-off (TTO) tasks to value five different EQ-5D-5L health states. The difference in TTO values between mainland Chinese and Singaporean Chinese was examined using random-effects linear regression and logistic regression models.

RESULTS

A total of 194 eligible mainland Chinese and 145 eligible Singaporean Chinese provided data for this study. All ten health states considered, the mean TTO value was 0.18 for Singaporean Chinese and 0.35 for mainland Chinese, with the unadjusted and adjusted difference [95% confidence interval (CI)] being -0.17 (-0.28, -0.07) and -0.16 (-0.27, -0.05). Singaporean Chinese had substantially lower TTO values than mainland Chinese for states with severe or extreme problems, with the adjusted difference being -0.30 (95% CI -0.42, -0.17). On the other hand, Singaporean Chinese and mainland Chinese had similar TTO values for states with mild or moderate problems, with the adjusted (95% CI) difference being 0.04 (-0.07, 0.15). Logistic regression analysis showed that Singaporean Chinese were more likely to rate health states with severe or extreme problems as worse than death compared to mainland Chinese.

CONCLUSIONS

Mainland Chinese and Singaporean Chinese have different preferences for EQ-5D-5L health states, supporting the development of local value sets for the EQ-5D-5L instrument for the two populations.

TIFA, an inflammatory signaling adaptor, is tumor suppressive for liver cancer

TIFA (TNF receptor associated factor (TRAF)-interacting protein with a Forkhead-associated (FHA) domain), also called T2BP, was first identified using a yeast two-hybrid screening. TIFA contains a FHA domain, which directly binds phosphothreonine and phosphoserine, and a consensus TRAF6-binding motif. TIFA-mediated oligomerization and poly-ubiquitinylation of TRAF6 mediates signaling downstream of the Tumor necrosis factor alpha receptor 1 (TNFaR-I) and interleukin-1/Toll-like receptor 4 (TLR4) pathways. Examining TIFA expression in hepatocellular carcinoma (HCC) tissues microarrays, we noted marked decreases TIFA reactivity in tumor versus control samples. In agreement, we found that HCC cell lines show reduced TIFA expression levels versus normal liver controls. Reconstituting TIFA expression in HCC cell lines promoted two independent apoptosis signaling pathways: the induction of p53 and cell cycle arrest, and the activation of caspase-8 and caspase-3. In contrast, the expression of a non-oligomerizing mutant of TIFA impacted cells minimally, and suppression of TIFA expression protected cells from apoptosis. Mice bearing TIFA overexpression hepatocellular xenografts develop smaller tumors versus TIFA mutant tumors; terminal deoxynucleotidyl transferase dUTP nick end labeling staining demonstrates increased cell apoptosis, and decreased proliferation, reflecting cell cycle arrest. Interestingly, p53 has a greater role in decreased proliferation than cell death, as it appeared dispensable for TIFA-induced cell killing. The findings demonstrate a novel suppressive role of TIFA in HCC progression via promotion of cell death independent of p53.

Health-related quality of life of Asian patients with end-stage renal disease (ESRD) in Singapore

BACKGROUND

This study aimed to identify factors associated with the health-related quality of life (HRQOL) of multiethnic Asian end-stage renal disease (ESRD) patients treated with dialysis. The role of dialysis modality was also explored.

METHODS

Data used in this study were from two cross-sectional surveys of Singaporean ESRD patients on haemodialysis (HD) or peritoneal dialysis (PD). In both surveys, participants were assessed using the kidney disease quality of life (KDQOL) instrument and questions assessing socio-demographic characteristics. Clinical data including co-morbidity (measured by Charlson comorbidity index [CCI]), albumin level, haemoglobin level, and dialysis-related variables (e.g. dialysis vintage and dialysis adequacy) were retrieved from medical records. The 36-item KDQOL (KDQOL-36) was used to generate three summary scores (physical component summary [PCS], mental component summary [MCS] and kidney disease component summary [KDCS]) and two health utility scores (Short Form 6-dimension [SF-6D] and EuroQol 5-dimension [EQ-5D]). Linear regression analysis was performed to examine the association of factors with each of the HRQOL scale scores.

RESULTS

Five hundred and two patients were included in the study (mean age 57.1 years; male 52.4 %; HD 236, PD 266). Mean [standard deviation (SD)] PCS, MCS and KDCS scores were 37.9 (9.7), 46.4 (10.8) and 57.6 (18.1), respectively. Mean (SD) health utility score was 0.66 (0.12) for SF-6D and 0.60 (0.21) for EQ-5D. In multivariate regression analysis, factors found to be significantly associated with better HRQOL included: young (<45 years) or old age (>60 years), low CCI (<5), high albumin (≥37 g/l) and high haemoglobin (≥11 g/dl) with PCS; long dialysis vintage (≥3.5 years) with MCS; old age, Malay ethnicity and PD modality with KDCS; low CCI, high albumin and high haemoglobin with EQ-5D and high albumin with SF-6D.

CONCLUSIONS

Clinical characteristics are better predictors of HRQOL in ESRD patients than socio-demographics in Singapore. Dialysis modality has no impact on the health utility of those patients.

Association of PELI1 polymorphisms in systemic lupus erythematosus susceptibility in a Chinese population

Objective

Studies in animal models have indicated that Pellino 1 is involved in inflammatory and autoimmune diseases, such as systemic lupus erythematosus (SLE). The current study was designed to determine whether PELI1 confers genetic susceptibility to SLE in humans, as assessed in a Chinese Han population.

Methods

Blood samples were drawn from patients diagnosed with SLE and healthy volunteers. Three single nucleotide polymorphism (SNP) loci with a minor allele frequency of at least 0.05 were chosen to evaluate the correlation between PELI1 genotype and the incidence of SLE.

Results

There was a significant difference in the frequency distribution of the rs329497 allele between the SLE patients and the healthy controls (A vs. G; Bonferroni corrected p = 0.036, odds ratio = 0.75, 95% confidence interval = 0.60–0.94). No differences in the genotype and allele frequencies of other SNP loci were observed between the two groups. Furthermore, the alleles and genotypes of the three SNPs were not associated with lupus nephritis.

Conclusion

In the Chinese Han population, PELI1 SNPs may be associated with SLE susceptibility.

Cross-cultural measurement equivalence of the EQ-5D-5L items for English-speaking Asians in Singapore

PURPOSE

To investigate how the response labels of the 5-level EQ-5D (EQ-5D-5L) items are interpreted and used by English-speaking Chinese and non-Chinese Singaporeans, as a means to assessing whether those items are cross-culturally equivalent health-status measures in this Asian population.

METHODS

In face-to-face interviews, Chinese, Malay and Indian visitors to a primary care institution in Singapore were asked to rate the relative severity conveyed by EQ-5D-5L response labels, each containing the keyword of 'no(t),' 'slight(ly),' 'moderate(ly),' 'severe(ly),' or 'unable'/'extreme(ly),' using a 0-100 numerical rating scale. Participants were also asked to describe 25 hypothetical health states using the EQ-5D-5L response labels. Differences between Chinese and Malay/Indian participants in label interpretation and selection were examined using multivariate regression analysis to adjust for participant characteristics.

RESULTS

The differences in adjusted mean severity scores for individual EQ-5D-5L labels between Chinese (n = 148) and non-Chinese (Malay: n = 53; Indian: n = 56) participants ranged from 0.0 to 9.0. The relative severity of the labels to the participants supported the ordinality of the EQ-5D-5L response labels and was similar across ethnic groups. Chinese and non-Chinese participants selected similar response labels to describe each hypothetical health state, with the adjusted odds ratios of selecting any type of the five response labels for non-Chinese versus Chinese participants ranging from 0.92 to 1.15 (p > 0.05 for all).

CONCLUSIONS

The EQ-5D-5L items are likely to generate equivalent health outcomes between English-speaking Chinese and non-Chinese Singaporeans.

Immunological changes after ASIT in AD allergen-specific immunotherapy and their potential correlation with clinical response in patients with atopic dermatitis patients sensitized to house dust mite

BACKGROUND

Allergen-specific immunotherapy (ASIT) is the main treatment for inducing long-term immunological and clinical tolerance in patients with IgE-mediated allergic diseases. Recent open-label and controlled studies on the efficacy of ASIT in patients with atopic dermatitis (AD) have provided promising results. However, data about possible relationship between the improvement of clinical symptoms and changes of serum cytokines are limited.

METHODS

Seventy-nine patients with moderate to severe AD sensitized to house dust mite (HDM) were enrolled. Fifty-eight patients were treated with ASIT and 11 controls received only symptomatic treatment. The disease activity in AD patients was evaluated by using the patient-oriented eczema measure (POEM) system. Serum interleukin (IL)-4, IL-10, interferon (IFN)-γ, transforming growth factor (TGF) β1, total IgE, HDM-specific IgE (s-IgE) and HDM-specific IgG4 (s-IgG4) were measured before and after 2 years of therapy.

RESULTS

The mean patient-oriented eczema measure system (POEM) score of AD patients with ASIT significantly decreased after 2 years of treatment, compared to that in patients without ASIT. After ASIT, the serum levels of IL-10, TGF-β1, IFN-γ and s-IgG4 increased, while the level of IL-4 decreased. The change in the POEM score was negatively correlated with changes of serum concentration of TGF-β1, s-IgG4 and IFN-γ. Furthermore, s-IgG4 levels were positively correlated with changes in the IL-10 levels. No correlation between POEM score and serum IL-10 or IL-4 was observed.

CONCLUSION

Clinical symptoms and the quality of life of AD with HDM sensitization could be improved after 2 years of ASIT. Changes in serum IL-10, TGF-β1, s-IgG4 and IFN-γ might be considered as biomarkers to assist clinical evaluation of the therapeutic effects of ASIT in patients with AD.

Caspase-9 mediates Puma activation in UCN-01-induced apoptosis

The protein kinase inhibitor 7-hydroxystaurosporine (UCN-01) is one of the most potent and frequently used proapoptotic stimuli. The BH3-only molecule of Bcl-2 family proteins has been reported to contribute to UCN-01-induced apoptosis. Here we have found that UCN-01 triggers Puma-induced mitochondrial apoptosis pathway. Our data confirmed that Akt-FoxO3a pathway mediated Puma activation. Importantly, we elucidate the detailed mechanisms of Puma-induced apoptosis. Our data have also demonstrated that caspase-9 is a decisive molecule of Puma induction after UCN-01 treatment. Caspase-9 mediates apoptosis through two kinds of feedback loops. On the one hand, caspase-9 enhances Puma activation by cleaving Bcl-2 and Bcl-xL independent of caspase-3. On the other hand, caspase-9 directly activated caspase-3 in the presence of caspase-3. Caspase-3 could cleave XIAP in an another positive feedback loop to further sensitize cancer cells to UCN-01-induced apoptosis. Therefore, caspase-9 mediates Puma activation to determine the threshold for overcoming chemoresistance in cancer cells.

Prostaglandin A2 enhances cellular insulin sensitivity via a mechanism that involves the orphan nuclear receptor NR4A3

We have previously reported that members of the NR4A family of orphan nuclear receptors can augment insulin's ability to stimulate glucose transport in adipocytes. In the current study, we endeavored to test for an insulin-sensitizing effect in muscle cells and to identify a potential transactivator. Lentiviral constructs were used to engineer both hyperexpression and shRNA silencing of NR4A3 in C2C12 myocytes. The NR4A3 hyper-expression construct led to a significant increase in glucose transport rates in the presence of maximal insulin while the NR4A3 knock-down exhibited a significant reduction in insulin-stimulated glucose transport rates. Consistently, insulin-mediated AKT phosphorylation was increased by NR4A3 hyperexpression and decreased following shRNA NR4A3 suppression. Then, we examined effects of prostaglandin A2 (PGA2) on insulin action and NR4A3 transactivation. PGA2 augmented insulin-stimulated glucose uptake in C2C12 myocytes and AKT phosphorylation after 12-h treatment, without significant effects on basal transport or basal AKT phosphorylation. More importantly, we demonstrated that PGA2 led to a greater improvement in insulin-stimulated glucose rates in NR4A3 overexpressing C2C12 myocytes, when compared with Lac-Z controls stimulated with insulin and PGA2. Moreover, the sensitizing effect of PGA2 was significantly diminished in NR4A3 knockdown myocytes compared to scramble controls. These results show for the first time that: (i) PGA2 augments insulin action in myocytes as manifested by enhanced stimulation of glucose transport and AKT phosphorylation; and (ii) the insulin sensitizing effect is dependent upon the orphan nuclear receptor NR4A3.

Effects of transcranial direct current stimulation on hemichannel pannexin-1 and neural plasticity in rat model of cerebral infarction

The aim of this study was to investigate the effects of transcranial direct current stimulation (TDCS) on hemichannel pannexin-1 (PX1) in cortical neurons and neural plasticity, and explore the optimal time window of TDCS therapy after stroke. Adult male Sprague-Dawley rats (n=90) were randomly assigned to sham operation, middle cerebral artery occlusion (MCAO), and TDCS groups, and underwent sham operation, unilateral middle cerebral artery (MCA) electrocoagulation, and unilateral MCA electrocoagulation plus TDCS (daily anodal and cathodal 10 Hz, 0.1 mA TDCS for 30 min beginning day 1 after stroke), respectively. Motor function was assessed using the beam walking test (BWT), and density of dendritic spines (DS) and PX1 mRNA expression were compared among groups on days 3, 7, and 14 after stroke. Effects of PX1 blockage on DS in hippocampal neurons after hypoxia-ischemia were observed. TDCS significantly improved motor function on days 7 and 14 after stroke as indicated by reduced BWT scores compared with the MCAO group. The density of DS was decreased after stroke; the TDCS group had increased DS density compared with the MCAO group on days 3, 7, and 14 (all P<0.0001). Cerebral infarction induced increased PX1 mRNA expression on days 3, 7, and 14 (P<0.0001), and the peak PX1 mRNA expression was observed on day 7. TDCS did not decrease the up-regulated PX1 mRNA expression after stroke on day 3, but did reduce the increased post-stroke PX1 mRNA expression on days 7 and 14 (P<0.0001). TDCS increased the DS density after stroke, indicating that it may promote neural plasticity after stroke. TDCS intervention from day 7 to day 14 after stroke demonstrated motor function improvement and can down-regulate the elevated PX1 mRNA expression after stroke.

Estimating the lifetime economic burden of Parkinson's disease in Singapore

BACKGROUND AND PURPOSE

We aimed to estimate the lifetime cost of Parkinson's disease (PD) from the societal perspective.

METHODS

A convenience sample of English or Chinese-speaking patients with PD was recruited from a PD and Movement Disorders Centre in Singapore to complete a financial burden questionnaire. Sociodemographic and clinical data were retrieved from hospital databases. Markov cohort model analysis was performed (cycle length, 1-year; duration, death or reached 100 years old). Patients were assumed to progress from one Markov state to the next state or death without skipping states or regressing. All model parameters were based on published local data.

RESULTS

In 195 patients with PD (median age: 68.9, male: 51.8%), the simulated lifetime cost of PD was Singapore Dollar (SGD) 60,487 (EUR purchasing power parity 56,253) per patient. Direct medical, non-medical and indirect cost accounted for 18.8%, 12.8% and 68.4% of total lifetime cost, respectively. The top three components of total lifetime cost were productivity losses (67.6%), pharmacotherapy (11.4%) and home care (8.7%). One-way sensitivity analysis and probabilistic sensitivity analyses revealed that estimates were sensitive to cost at H&Y stage 1, 2 and 2.5 and productivity losses.

CONCLUSIONS

The lifetime cost of PD is evaluated for the first time. This cost is substantial and comparable to the lifetime cost of intracerebral haemorrhage in at least one study. Our study identified several priority areas for research and policy formulation: reducing productivity losses, reducing cost of pharmacotherapy, avoiding hospitalization and reducing home care cost.

Validity of EuroQOL-5D, time trade-off, and standard gamble for age-related macular degeneration in the Singapore population

BACKGROUND/AIMS

Utility values of age-related macular degeneration (AMD) in Asian patients are unknown. This study aims to assess utility values and construct validity of the EuroQOL-5D (EQ-5D), time trade-off (TTO), and standard gamble (SG) instruments in the Singapore multi-ethnic AMD population.

METHODS

Cross-sectional, two-centre, institution-based study. Visual acuity (VA), clinical AMD severity, and utility scores on the EQ-5D, TTO, and SG were obtained from 338 AMD patients. VA was analysed in terms of the better-seeing eye (BEVA), worse-seeing eye (WEVA), and weighted average of both eyes (WVA). We evaluated SG on the perfect health-death (SG(death)) and binocular perfect vision-binocular blindness (SG(blindness)) scales. Construct validity was determined by testing a priorihypotheses relating the EQ-5D, TTO, and SG utility scores to VA and clinical AMD severity.

RESULTS

The mean utilities on the EQ-5D, TTO, SG(death), and SG(blindness) were 0.89, 0.81, 0.86, and 0.90, respectively. EQ-5D scores correlated weakly with BEVA, WEVA, and WVA (Pearson's correlation coefficients -0.291, -0.247, and -0.305 respectively, P<0.001 for all). SG(death) and SG(blindness) demonstrated no correlation with BEVA, WEVA, or WVA (Pearson's correlation coefficients, range -0.06 to -0.125). TTO showed weak association only with WEVA and WVA (correlation coefficients -0.237, -0.228, P<0.0001), but not with BEVA (correlation coefficient -0.161). Clinical AMD severity correlated with EQ-5D and SG(death), but not with TTO and SG(blindness) (P=0.004, 0.002, 0.235, and 0.069, respectively).

CONCLUSIONS

AMD has a negative impact on utilities, although utility scores were high compared with Western cohorts. EQ-5D, TTO, and SG showed suboptimal construct validity, suggesting that health status utilities may not be sufficiently robust for cost-utility analyses in this population.

Economic burden of Parkinson's disease in Singapore

BACKGROUND

This study was carried out to evaluate the economic burden of Parkinson's disease (PD) and factors independently associated with individual components of total cost in Singapore.

METHODS

A consecutive sample of 195 patients with PD (mean age: 68.2, men: 51.8%) attending a tertiary neuroscience clinic were identified and interviewed using standardized questionnaires including a financial burden questionnaire, two Health Related Quality of Life (HRQoL) questionnaires and the Beck Depression Inventory questionnaire.

RESULTS

Annual total cost of PD from a societal perspective was SGD11345 (USD10129) per patient, with direct cost accounted for 38.5% and indirect cost 61.5%. The main cost components for direct medical cost, direct non-medical cost, and indirect cost was pharmacotherapy (50.4%), home care (76.1%), and productivity loss (97.9%), respectively. In multiple linear regression analysis, higher education, younger age and longer duration of PD were associated with higher total cost.

CONCLUSIONS

Parkinson's disease exerts a considerable burden on patients, health care system and society in Singapore. As productivity loss accounts for a large share of the economic burden imposed by PD, treatments and health care programmes with potential for returning patients to higher productivity are urgently needed.