Shenshen Wu

FAS rs2234767 and rs1800682 polymorphisms jointly contributed to risk of colorectal cancer by affecting SP1/STAT1 complex recruitment to chromatin

FAS rs2234767 (−1377 G>A), rs1800682 (−670 A>G) and FASLG rs763110 (−844 C>T) promoter polymorphisms can influence transcriptional activities of the genes and thus multiple tumors susceptibility. To investigate their association with risk of colorectal cancer (CRC), the three SNPs were genotyped in 878 cases and 884 controls and the results showed that the FAS rs2234767 and rs1800682 were in a high linkage disequilibrium (LD) with each other (D’ = 0.994) and jointly contributed to an increased risk of CRC (without vs. with rs2234767 GG/rs1800682 AA genotypes, adjusted OR = 1.30, 95% CI = 1.05 − 1.61). In vivo ChIP assays evaluated the effect of rs2234767 and rs1800682 on recruitment of SP1 and STAT1, respectively, to chromatin. The results showed SP1 interacting specifically with STAT1 recruited to their respective motifs for transcriptional activation. The mutant alleles rs2234767 A and rs1800682 G jointly affected coupled SP1 and STAT1 recruitment to chromatin. The interplay between SP1 and STAT1 was critical for the functional outcome of rs2234767 and rs1800682 in view of their high LD. In conclusion, the FAS rs2234767 and rs1800682 polymorphisms were in high LD with each other, and they jointly contributed to an increased risk of CRC by altering recruitment of SP1/STAT1 complex to the FAS promoter for transcriptional activation.

MicroRNA-1228* inhibit apoptosis in A549 cells exposed to fine particulate matter

Studies have reported associations between fine particulate matter (PM2.5) and respiratory disorders; however, the underlying mechanism is not completely clear owing to the complex components of PM2.5. microRNAs (miRNAs) demonstrate tremendous regulation to target genes, which are sensitive to exogenous stimulation, and facilitate the integrative understood of biological responses. Here, significantly modulated miRNA were profiled by miRNA microarray, coupled with bioinformatic analysis; the potential biological function of modulated miRNA were predicted and subsequently validated by cell-based assays. Downregulation of miR-1228-5p (miR-1228*) expression in human A549 cells were associated with PM2.5-induced cellular apoptosis through a mitochondria-dependent pathway. Further, overexpression of miR-1228* rescued the cellular damages induced by PM2.5. Thus, our results demonstrate that PM2.5-induced A549 apoptosis is initiated by mitochondrial dysfunction and miR-1228* could protect A549 cells against apoptosis. The involved pathways and target genes might be used for future mechanistic studies.

An acetyl-L-carnitine switch on mitochondrial dysfunction and rescue in the metabolomics study on aluminum oxide nanoparticles

BackgroundDue to the wide application of engineered aluminum oxide nanoparticles and increased aluminum containing particulate matter suspending in air, exposure of human to nano-scale aluminum oxide nanoparticles (Al2O3 NPs) is becoming inevitable.MethodsIn the present study, RNA microarray coupled with metabolomics analysis were used to uncover mechanisms underlying cellular responses to Al2O3 NPs and imply the potential rescue.ResultsWe found that Al2O3 NPs significantly triggered down-regulation of mitochondria-related genes located in complex I, IV and V, which were involved in oxidative phosphorylation and neural degeneration pathways, in human bronchial epithelial (HBE) cells. Subsequent cell- and animal- based assays confirmed that Al2O3 NPs caused mitochondria-dependent apoptosis and oxidative stress either in vitro or in vivo, which were consistent with the trends of gene regulation. To rescue the Al2O3 NPs induced mitochondria dysfunction, disruption of small molecular metabolites of HBE were profiled using metabolomics analysis, which facilitates identification of potential antagonizer or supplement against nanoparticle-involved damages. Supplementation of an antioxidant, acetyl-L-carnitine, completely or partially restored the Al2O3 NPs modulated gene expression levels in mitochondrial complex I, IV and V. It further reduced apoptosis and oxidative damages in both Al2O3 NPs treated HBE cells and animal lung tissues.ConclusionThus, our results demonstrate the potential mechanism of respiratory system damages induced by Al2O3 NPs. Meanwhile, based on the metabolomics profiling, application of acetyl-L-carnitine is suggested to ameliorate mitochondria dysfunction associated with Al2O3 NPs.

Sex-Dependent Depression-Like Behavior Induced by Respiratory Administration of Aluminum Oxide Nanoparticles

Ultrafine aluminum oxide, which are abundant in ambient and involved occupational environments, are associated with neurobehavioral alterations. However, few studies have focused on the effect of sex differences following exposure to environmental Al2O3 ultrafine particles. In the present study, male and female mice were exposed to Al2O3 nanoparticles (NPs) through a respiratory route. Only the female mice showed depression-like behavior. Although no obvious pathological changes were observed in mice brain tissues, the neurotransmitter and voltage-gated ion channel related gene expression, as well as the small molecule metabolites in the cerebral cortex, were differentially modulated between male and female mice. Both mental disorder-involved gene expression levels and metabolomics analysis results strongly suggested that glutamate pathways were implicated in sex differentiation induced by Al2O3 NPs. Results demonstrated the potential mechanism of environmental ultrafine particle-induced depression-like behavior and the importance of sex dimorphism in the toxic research of environmental chemicals.

microRNA-802/Rnd3 pathway imposes on carcinogenesis and metastasis of fine particulate matter exposure

Recent studies have linked ambient fine particulate matter (PM2.5) to increased lung cancer mortality and morbidity. However, the underlying mechanism causing the adverse effects of PM2.5 is less clear. In the present study, post-transcriptional profiling was used to explore biological pathways involved in PM2.5-induced pulmonary disorders. The carcinogenesis and metastasis of PM2.5 exposure were evaluated by long-term PM2.5 exposure tests. We observed dysregulation of actin in A549 cells line and dysplasia in the lungs of mice exposed to PM2.5. Both PM2.5-exposed cells and animals showed increased Rnd3 expression levels. Moreover, miR-802 mimics rescued actin disorganization in vitro and alveolitis in vivo. Long-term exposure to PM2.5 promoted carcinogenesis and metastasis of pulmonary cells. Decreased miR-802 expression levels in the serum samples of PM2.5-treated mice and individuals from moderately polluted cities were observed. Increased Rnd3 expression levels in lung cancers tissues have been identified by a genome database TCGA, and have been linked to less overall survival probabilities of lung cancer patients. Our findings suggest that dysregulation of actin cytoskeleton and down-regulation of miR-802 expression might be the underlying mechanism involved in the adverse effects of PM2.5 exposure. In addition, long-term exposure to PM2.5 demonstrated strong associations with malignant pulmonary disorders.

Integrative functional transcriptomic analyses implicate specific molecular pathways in pulmonary toxicity from exposure to aluminum oxide nanoparticles

Abstract Gene expression profiling has developed rapidly in recent years and it can predict and define mechanisms underlying chemical toxicity. Here, RNA microarray and computational technology were used to show that aluminum oxide nanoparticles (Al2O3 NPs) were capable of triggering up-regulation of genes related to the cell cycle and cell death in a human A549 lung adenocarcinoma cell line. Gene expression levels were validated in Al2O3 NPs exposed A549 cells and mice lung tissues, most of which showed consistent trends in regulation. Gene-transcription factor network analysis coupled with cell- and animal-based assays demonstrated that the genes encoding PTPN6, RTN4, BAX and IER play a role in the biological responses induced by the nanoparticle exposure, which caused cell death and cell cycle arrest in the G2/S phase. Further, down-regulated PTPN6 expression demonstrated a core role in the network, thus expression level of PTPN6 was rescued by plasmid transfection, which showed ameliorative effects of A549 cells against cell death and cell cycle arrest. These results demonstrate the feasibility of using gene expression profiling to predict cellular responses induced by nanomaterials, which could be used to develop a comprehensive knowledge of nanotoxicity.

PSCA rs2294008 polymorphism contributes to the decreased risk for cervical cancer in a Chinese population

Recently, three genome-wide association studies have identified the PSCA (prostate stem cell antigen) rs2294008 polymorphism (C > T) associated with susceptibility to gastric cancer, bladder cancer, and duodenal ulcers, highlighting its critical role in disease pathogenesis. Given PSCA is reported to be overexpressed in cervical cancer and the rs2294008 can influence PSCA transcription, we aimed to determine the role of rs2294008 in susceptibility to cervical cancer. The genotyping was performed in the 1126 cases and 1237 controls. Our results showed the rs2294008 TT genotype significantly associated with a reduced risk of cervical cancer (adjusted OR = 0.55, 95% CI = 0.38–0.79; recessive model). Stratified analyses revealed that the association was restricted to the subgroups of age > 49 years, parity ≤ 1, abortion and early-stage cervical cancer. Immunohistochemistry assay showed the individuals carrying the TT genotype having lower PSCA expression than those with CC/CT genotypes. In summary, the PSCA rs2294008 polymorphism may serve as a biomarker of cervical cancer, particularly of early-stage cervical cancer.

Role of astrocyte activation in fine particulate matter-enhancement of existing ischemic stroke in Sprague-Dawley male rats

ABSTRACT Exposure to particulate matter (PM) with an aerodynamic diameter of less than 2.5 μm (PM2.5) is associated with increased risk of ischemic stroke, but potential neurotoxic mechanisms remain to be determined. In this study, adult male Sprague- Dawley (SD) rats were divided into four groups as follows: control (CON), PM2.5 exposure (PM alone), ischemic stroke (IS), and ischemic stroke and PM2.5 (IS-PM). Ischemic stroke groups were prepared by middle cerebral artery occlusion (MCAO), and neurobehavior was assessed daily for 7 consecutive days. The control group was administered intranasally 20 μl PBS, while PM2.5 alone was given as 20 μl of PM2.5 (10 mg/ml) intranasal daily for 7 consecutive days. The spontaneous locomotion and exploratory behavior of rats were assessed by the open field test. Cells positive for glial fibrillary acidic protein (GFAP) and inducible nitric oxide synthase (iNOS) were determined for astrocyte activation and inflammatory reactions. Neuronal edema and pyknosis in the cerebral cortex, hippocampus, and midbrain were observed in IS groups with or without PM2.5 treatment. Astrocyte activity was enhanced, whereas spontaneous locomotion and exploratory movements decreased in the IS-PM group. Data demonstrated that astrocytes activation and inflammatory reactions may play a role in IS and that exposure to PM2.5 may aggravate the neurobehavioral alterations observed in rats suffering from IS.

A novel mechanism of rs763110 polymorphism contributing to cervical cancer risk by affecting the binding affinity of CEBP/β and OCT1 complex to chromatin

Recently, several studies have showed that FAS (rs2234767, rs1800682) and FASL (rs763110) functional single nucleotide polymorphisms (SNPs) were associated with the risk of various cancers. However, the association between cervical cancer risk and the three SNPs above remained inconclusive. In this work, we performed a two‐stage case–control study on 1155 cervical cancer patients and 1252 matched healthy controls to determine the roles of the mentioned SNPs in cervical cancer susceptibility. We genotyped the FAS rs2234767, rs1800682, and FASL rs763110 polymorphisms using PCR‐TaqMan assays. Results revealed that the rs763110 TT genotype significantly increased the risk of cervical cancer compared with the CC/CT genotype (adjusted OR = 1.70, 95% CI = 1.19–2.42). However, we did not observe any association between the cervical cancer risk and the rs2234767 and rs1800682 polymorphisms. The immunohistochemistry assay showed that patients carrying the rs763110 TT genotype presented a lower cancerous FASL expression than that of the CC/CT genotypes. Chromatin immunoprecipitation (ChIP) and Sequential Chromatin immunoprecipitation assays also demonstrated that OCT1 was recruited to the FASL promoter region and regulated the FASL gene transcription by interacting with C/EBPβ. In conclusion, this study provided evidence indicating that the rs763110 variant in the FASL promoter was associated with the risk of cervical cancer by affecting the binding affinity of the C/EBPβ/OCT1 complex to chromatin.

DR4 mediates the progression, invasion, metastasis and survival of colorectal cancer through the Sp1/NF1 switch axis on genomic locus: DR4 and development of colorectal cancer

The single nucleotide polymorphism (SNP), −397G > T (rs13278062) polymorphism, in the promoter of Death Receptor 4 (DR4) had been reported to be associated with a significantly increased risk for bladder cancer. However, the association of this SNP with the risk of colorectal cancer has not been reported. In this study, we performed a case–control study in 1,078 colorectal cancer patients and 1,175 matched healthy controls to evaluate the association of the potential functional genetic variants in DR4 with risk and survival of colorectal cancer. PCR‐TaqMan were used to genotype the rs13278062, rs1000294 and rs2235126 polymorphisms. We found that subjects carrying the rs13278062 GT/TT genotypes had a significantly lower risk and increased survival time when compared to the GG genotype. We also constructed the rs13278062 GT/TT genotype in SW480 and SW620 cells (rs13278062 is GG in both cell lines) with the CRISPR/Cas9 system. Flow cytometry experiments showed that the rs13278062 TT genotype promoted apoptosis in colorectal cancer cells. In vitro and in vivo experiments established that the rs13278062 G to T mutation inhibited carcinogenesis and metastasis of colorectal cancer. Chromatin immunoprecipitation (ChIP) assays revealed that the rs13278062 G > T polymorphism altered the binding affinity of the transcription factors Sp1/NF1 to the rs13278062 mutation region. Immunohistochemistry, western blot, and qPCR corroborated that the rs13278062 GT/TT genotypes increased the expression of DR4 protein in colorectal cancer tissues and cells. In conclusion, these findings indicate that DR4 mediated progression, invasion, metastasis and survival of colorectal cancer via the Sp1/NF1 switch axis on genomics locus.