The Liver X Receptor Is Selectively Modulated to Differentially Alter Female Mammary Metastasis-associated Myeloid Cells.

Dysregulation of cholesterol homeostasis is associated with many diseases such as cardiovascular disease and cancer. Liver X receptors (LXRs) are major upstream regulators of cholesterol homeostasis and are activated by endogenous cholesterol metabolites such as 27-hydroxycholesterol (27HC). LXRs and various LXR ligands such as 27HC have been described to influence several extra-hepatic biological systems. However, disparate reports of LXR function have emerged, especially with respect to immunology and cancer biology. This would suggest that, similar to steroid nuclear receptors, the LXRs can be selectively modulated by different ligands. Here, we use RNA-sequencing of macrophages and single-cell RNA-sequencing of immune cells from metastasis-bearing murine lungs to provide evidence that LXR satisfies the 2 principles of selective nuclear receptor modulation: (1) different LXR ligands result in overlapping but distinct gene expression profiles within the same cell type, and (2) the same LXR ligands differentially regulate gene expression in a highly context-specific manner, depending on the cell or tissue type. The concept that the LXRs can be selectively modulated provides the foundation for developing precision pharmacology LXR ligands that are tailored to promote those activities that are desirable (proimmune), but at the same time minimizing harmful side effects (such as elevated triglyceride levels).

Genetic Polymorphisms in the Vitamin D Pathway and Non-small Cell Lung Cancer Survival.

Various genetic polymorphisms have been linked to lung cancer susceptibility and survival outcomes. Vitamin D (VD) regulates cell proliferation and differentiation, inhibits tumor growth and induces apoptosis. Observations from several previous studies including our own suggest that genetic polymorphisms in the VD pathway may be associated with lung cancer risk. The aim of this study is to assess if genetic polymorphisms in the VD pathway are associated with the prognosis of non-small cell lung cancer (NSCLC). Nine single nucleotide polymorphisms (SNPs) in five genes in the VD pathway were genotyped with the TaqMan assays in 542 patients with primary NSCLC, and the relationships between these SNPs and overall survival were evaluated. We found that SNP rs10741657 in the CYP2R1 gene was associated with the prognosis of NSCLC, especially in elderly patients and not being treated with chemotherapy. Some of the VD pathway-related genetic polymorphisms may influence the prognosis of NSCLC. More research is needed to further confirm the finding and test if VD supplements can be used for NSCLC treatment.

RYBP predicts survival of patients with non-small cell lung cancer and regulates tumor cell growth and the response to chemotherapy.

Ring1 and YY1 binding protein (RYBP) is a member of the Polycomb group (PcG) proteins and regulates cell growth through both PcG-dependent and -independent mechanisms. Our initial study indicated that RYBP is down-regulated in human non-small cell lung cancer (NSCLC) tissues. The present study determined the molecular role of RYBP in the development of NSCLC. We systemically investigated the association between the RYBP expression and the survival of patients with NSCLC. We also carried out in vitro and in vivo studies to explore the molecular basis for the tumor suppressor role of RYBP in NSCLC. Our clinical results demonstrated that the RYBP mRNA and protein expressions were significantly down-regulated in NSCLC and significantly linked to the poor prognosis in NSCLC patients. The enforced expression of RYBP inhibited cell survival, induced apoptosis, and increased chemosensitivity in NSCLC cells; knockdown of RYBP showed the opposite effects. Moreover, adenoviral delivery of RYBP sensitized the NSCLC cells to chemotherapy in vivo. In addition, RYBP expression was induced by paclitaxel, the first-line chemotherapeutic agent for NSCLC. Our results reveal that RYBP inhibits the aggressiveness of NSCLC cells and downregulation of RYBP is associated with poor prognosis, suggesting that RYBP could be developed as a biomarker and a novel target for therapy in patients with lung cancer.

DNA Repair Gene Polymorphisms in Relation to Non-Small Cell Lung Cancer Survival.

BACKGROUND: Single nucleotide polymorphisms (SNPs) in the DNA repair genes are suspected to be related to the survival of lung cancer patients due to their possible influence on DNA repair capacity (DRC). However, the study results are inconsistent. METHODS: A follow-up study of 610 non-small cell lung cancer (NSCLC) patients was conducted to investigate genetic polymorphisms associated with the DNA repair genes in relation to NSCLC survival; 6 SNPs were genotyped, including XRCC1 (rs25487 G>A), hOGG1 (rs1052133 C>G), MUTYH (rs3219489 G>C), XPA (rs1800975 G>A), ERCC2 (rs1799793 G>A) and XRCC3 (rs861539 C>T). Kaplan- Meier survival curve and Cox proportional hazards regression analyses were performed. SNP-SNP interaction was also examined using the survival tree analysis. RESULTS: Advanced disease stage and older age at diagnosis were associated with poor prognosis of NSCLC. Patients with the variant 'G' allele of hOGG1 rs1052133 had poor overall survival compared with those with the homozygous wild 'CC' genotype, especially in female patients, adenocarcinoma histology, early stage, light smokers and without family history of cancer. For never smoking female lung cancer patients, individuals carrying homozygous variant 'AA' genotype of XPA had shorter survival time compared to those with wild 'G' alleles. Furthermore, females carrying homozygous variant XPA and hOGG1 genotypes simultaneously had 2.78-fold increased risk for death. Among all 6 polymorphisms, the homozygous variant 'AA' of XPA carriers had poor prognosis compared to the carriers of wild 'G' alleles of XPA together with other base excision repair (BER) polymorphisms. CONCLUSIONS: Besides disease stage and age, the study found DNA repair gene polymorphisms were associated with lung cancer survival.

MiR-195 suppresses non-small cell lung cancer by targeting CHEK1.

MiR-195 suppresses tumor growth and is associated with better survival outcomes in several malignancies including non-small cell lung cancer (NSCLC). Our previous study showed high miR-195 plasma levels associated with favorable overall survival of non-smoking women with lung adenocarcinoma. To further elucidate role of miR-195 in NSCLC, we conducted in vitro experiment as well as clinical studies in a cohort of 299 NSCLC samples. We demonstrated that miR-195 expression was lower in tumor tissues and was associated with poor survival outcome. Overexpression of miR-195 suppressed tumor cell growth, migration and invasion. We discovered that CHEK1 was a direct target of miR-195, which decreased CHEK1 expression in lung cancer cells. High expression of CHEK1 in lung tumors was associated with poor overall survival. Our results suggest that miR-195 suppresses NSCLC and predicts lung cancer prognosis.

Genetic polymorphisms in the vitamin D pathway in relation to lung cancer risk and survival.

Studies have suggested that vitamin D may have protective effects against cancer development or tumor progression. To search for additional evidence, we investigated the role of genetic polymorphisms involved in the vitamin D pathway in non-small cell lung cancer (NSCLC). We evaluated common genetic polymorphisms associated with the vitamin D pathway in relation to NSCLC in a case-control study of 603 newly diagnosed NSCLC patients and 661 matched healthy controls. Seven single nucleotide polymorphisms (SNPs) were genotyped, the expression of CYP27B1 and CYP24A1 were measured in 153 tumor samples and their associations with genotypes and patient survival were also analyzed. In the case-control comparison, we found SNP rs3782130 (CYP27B1), rs7041 (GC), rs6068816 and rs4809957 (CYP24A1) associated with NSCLC risk. The risk of NSCLC was increased with the number of risk alleles. CYP27B1 and CYP24A1 expression were significantly different between tumor and normal tissues in NSCLC. High CYP27B1 expression was associated with better overall survival, and the expression was different by the rs3782130 genotype. The study suggests that some genetic polymorphisms involved in the vitamin D pathway may associate with NSCLC risk, and one of the polymorphisms (rs3782130) may affect gene expression and patient survival.

The incidence of lung cancer by histological type: a population-based study in Tianjin, China during 1981-2005.

BACKGROUND AND OBJECTIVE: Lung cancer remains the leading cause of cancer deaths worldwide. The aim of this study was to examine the trend in the incidence of lung cancer, validated by histology in Tianjin, the third largest municipal city in China, during the period from 1981 to 2005. METHODS: New lung cancer cases, crude incidence rates and age-adjusted rates by histological type were analysed using the data from the Tianjin Cancer Registry, which covers a population of 4 million urban residents. RESULTS: The most common histological types of lung cancer were squamous cell carcinoma (SQCC) in men and adenocarcinoma (ADC) in women. During the 25-year period, the constitutive pattern of the histological types changed gradually, ADC increased by 31.4%, but SQCC decreased by 25.6% among women. For SQCC, ADC or small cell carcinoma (SMCC), both the new cases and crude incidences per year increased among men and women. However, the age-adjusted incidences of all types of lung cancer showed an initial increase, which then levelled off or declined in recent years. The birth-cohort incidence analyses revealed that SQCC declined sharply, while ADC still increased among the younger age groups. CONCLUSION: The incidences of lung cancer by histological type changed during the 25-year period in Tianjin. Tailored strategies on prevention and control should be developed to meet the needs for various populations.

Prognostic implications for high expression of MiR-25 in lung adenocarcinomas of female non-smokers.

BACKGROUND: Adenocarcinoma (ADC) is the most common histological type of lung cancer and its proportion is rising, especially in Asian non-smoking women. Recent studies suggest miR-25 may have diverse effects on the pathogenesis of different types of cancer. However, the role of miR-25 in lung cancer is still unknown. The aim of this study was to investigate the potential clinical value of miR-25 in non-smoking women with lung ADC. PATIENTS AND METHODS: Quantitative RT-PCR was performed to evaluate the expression of miR-25 in 100 lung ADC tumor tissues and matched plasma samples and Pearson correlation tests were used to analyze the relationship between values. Associations of miR-25 expression with clinicopathological features were determined using the Student's t-test. To determine prognostic value, overall survival (OS) was evaluated using the Kaplan-Meier method. Univariate and multivariate analyses were performed using the Cox proportional hazard model. RESULTS: Expression of miR-25 in tissue was found to be associated with lymph node metastasis (P=0.021) and disease stage (P=0.012). Moreover, high miR-25 expression was also associated with poorer overall survival of women with lung ADC (P=0.008). CONCLUSION: Tissue miR-25 expression may be associated with tumor progression and have prognostic implications in female lung ADC patients.

Circulating microRNAs in relation to EGFR status and survival of lung adenocarcinoma in female non-smokers.

OBJECTIVES: Lung adenocarcinoma is considered a unique disease for Asian female non-smokers. We investigated whether plasma microRNA (miRNA) expression profiles are different by the EGFR status and are associated with survival outcomes of the patients. METHODS: Using real-time RT-PCR, we analyzed the expression of 20 miRNAs in the plasma of 105 female patients with lung adenocarcinoma. Kaplan-Meier survival analysis and Cox proportional hazards regression were performed to determine the association between miRNA expression and overall survival. Time dependent receiver operating characteristic (ROC) analysis was also performed. RESULTS: In the 20 miRNAs, miR-122 were found differently expressed between wild and mutant EGFR carriers (P=0.018). Advanced disease stage and tumor metastasis were independently associated with poor prognosis of patients with lung adenocarcinoma (P=0.010 and 1.0×10(-4)). Plasma levels of miR-195 and miR-122 expression were also associated with overall survival in the patients, especially in those with advanced stage (HR=0.23, 95%CI:0.07-0.84; and HR=0.22, 95%CI:0.06-0.77) and EGFR mutation (HR=0.27, 95%CI:0.08-0.96; and HR=0.23, 95%CI=0.06-0.81). Moreover, a model including miR-195, miR-122 may predict survival outcomes of female patients with lung adenocarcinoma (AUC=0.707). CONCLUSIONS: Circulating miR-195 and miR-122 may have prognostic values in predicting the overall survival as well as predicting EGFR mutation status in non-smoking female patients with lung adenocarcinoma. Measuring plasma levels of miR-195 and miR-122 may especially be useful in EGFR mutant patients with lung adenocarcinoma.

Greater antioxidant and respiratory metabolism in field-grown soybean exposed to elevated O3 under both ambient and elevated CO2.

Antioxidant metabolism is responsive to environmental conditions, and is proposed to be a key component of ozone (O(3)) tolerance in plants. Tropospheric O(3) concentration ([O(3)]) has doubled since the Industrial Revolution and will increase further if precursor emissions rise as expected over this century. Additionally, atmospheric CO(2) concentration ([CO(2)]) is increasing at an unprecedented rate and will surpass 550 ppm by 2050. This study investigated the molecular, biochemical and physiological changes in soybean exposed to elevated [O(3) ] in a background of ambient [CO(2)] and elevated [CO(2)] in the field. Previously, it has been difficult to demonstrate any link between antioxidant defences and O(3) stress under field conditions. However, this study used principle components analysis to separate variability in [O(3)] from variability in other environmental conditions (temperature, light and relative humidity). Subsequent analysis of covariance determined that soybean antioxidant metabolism increased with increasing [O(3)], in both ambient and elevated [CO(2)]. The transcriptional response was dampened at elevated [CO(2)], consistent with lower stomatal conductance and lower O(3) flux into leaves. Energetically expensive increases in antioxidant metabolism and tetrapyrrole synthesis at elevated [O(3)] were associated with greater transcript levels of enzymes involved in respiratory metabolism.

Genomic basis for stimulated respiration by plants growing under elevated carbon dioxide.

Photosynthetic and respiratory exchanges of CO(2) by plants with the atmosphere are significantly larger than anthropogenic CO(2) emissions, and these fluxes will change as growing conditions are altered by climate change. Understanding feedbacks in CO(2) exchange is important to predicting future atmospheric [CO(2)] and climate change. At the tissue and plant scale, respiration is a key determinant of growth and yield. Although the stimulation of C(3) photosynthesis by growth at elevated [CO(2)] can be predicted with confidence, the nature of changes in respiration is less certain. This is largely because the mechanism of the respiratory response is insufficiently understood. Molecular, biochemical and physiological changes in the carbon metabolism of soybean in a free-air CO(2) enrichment experiment were investigated over 2 growing seasons. Growth of soybean at elevated [CO(2)] (550 micromol x mol(-1)) under field conditions stimulated the rate of nighttime respiration by 37%. Greater respiratory capacity was driven by greater abundance of transcripts encoding enzymes throughout the respiratory pathway, which would be needed for the greater number of mitochondria that have been observed in the leaves of plants grown at elevated [CO(2)]. Greater respiratory quotient and leaf carbohydrate content at elevated [CO(2)] indicate that stimulated respiration was supported by the additional carbohydrate available from enhanced photosynthesis at elevated [CO(2)]. If this response is consistent across many species, the future stimulation of net primary productivity could be reduced significantly. Greater foliar respiration at elevated [CO(2)] will reduce plant carbon balance, but could facilitate greater yields through enhanced photoassimilate export to sink tissues.

Safeners coordinately induce the expression of multiple proteins and MRP transcripts involved in herbicide metabolism and detoxification in Triticum tauschii seedling tissues.

Chemicals called safeners protect cereal crops from herbicide toxicity. Proteomic methods (2-D PAGE and LC-MS/MS) were utilized to identify safener- and/or herbicide-regulated proteins in three tissues (root, leaf, and coleoptile) of Triticum tauschii seedlings to better understand a safener's mechanism of action. Growth experiments showed that the safener cloquintocet-mexyl protected seedlings from injury by the herbicide dimethenamid. In total, 29 safener-induced and 10 herbicide-regulated proteins were identified by LC-MS/MS. These proteins were classified into two major categories based on their expression patterns, and were further classified into several functional groups. Surprisingly, mutually exclusive sets of proteins were identified following herbicide or safener treatment, suggesting that different signaling pathways may be recruited. Safener-responsive proteins, mostly involved in xenobiotic detoxification, also included several new proteins that had not been previously identified as safener-responsive, whereas herbicide-regulated proteins belonged to several classes involved in general stress responses. Quantitative RT-PCR revealed that multidrug resistance-associated protein (MRP) transcripts were highly induced by safeners and two MRP genes were differentially expressed. Our results indicate that safeners protect T. tauschii seedlings from herbicide toxicity by coordinately inducing proteins involved in an entire herbicide detoxification pathway mainly in the coleoptile and root, thereby protecting new leaves from herbicide injury.

Tissue-specific expression and localization of safener-induced glutathione S-transferase proteins in Triticum tauschii.

Glutathione S-transferase (GST; EC 2.5.1.18) gene expression was examined in the coleoptile and new leaf tissue of etiolated shoots of the diploid wheat species Triticum tauschii (Coss.) Schmal., which is considered to be a progenitor and the D-genome donor to cultivated, hexaploid bread wheat Triticum aestivum L. GST expression (mRNA, protein, and enzyme activity with a herbicide substrate) in these shoot tissues was examined in response to herbicide safener treatment. Two different antibody probes, raised against the same safener-inducible GST protein (TtGSTU1) but differing in their specificity, were utilized to determine tissue distribution and subcellular localization of GST proteins in etiolated shoots. GST transcripts, immunoreactive GST proteins, and herbicide-metabolizing activity were all highest in the coleoptile of etiolated, safener-treated T. tauschii shoots. Anti-GST immunolabeling was strongest in the outer epidermal and adjoining sub-epidermal cells in both coleoptiles and new leaves following safener treatment. Our data indicate that safeners protect grass crops from herbicide injury by dramatically inducing the expression of GST proteins in the outer cell layers of the coleoptile, which prevents the herbicide from reaching the sensitive new leaves of etiolated shoots as they emerge from the soil.

G-box binding coincides with increased Solanum melongena cysteine proteinase expression in senescent fruits and circadian-regulated leaves.

We have previously shown that SmCP, the gene encoding Solanum melongena cysteine proteinase, is expressed during developmental events associated with programmed cell death (PCD) suggesting its involvement in protein degradation during these events (Xu and Chye, Plant Journal 17 (1999) 321-327). Here, we investigated the regulation of SmCP expression and showed that it is ethylene-inducible and is under circadian control. This circadian rhythm is entrained by light/dark (LD) cycling with peak expression in the late light period, as opposed to that in early light for rbcS, suggesting that protein degradation and photosynthesis are temporally separated by circadian control. Northern blot analysis shows that the pattern of ethylene induction of SmCP is consistent with our previous observation of its significantly increased expression at leaf senescence and fruit ripening when endogenous ethylene is abundant. To further understand SmCP regulation, we have cloned the SmCP promoter and identified a G-box (CACGTG) at -85/-80 by DNase I footprinting analysis of the -221/+17 region. Its specific interaction with nuclear proteins in S. melongena leaves and fruits was confirmed by competitive electrophoretic mobility shift assays using oligonucleotides containing the G-box and mutant derivatives. G-box binding activity was stronger in senescent than young fruits. In circadian-regulated leaves, stronger binding activity coincided with peak circadian expression of SmCP. This correlation between binding activity and expression suggests that G-box binding factors enhance SmCP transcription and that the G-box likely plays a role in circadian regulation of genes affected by LD cycling.

Tandemly duplicated Safener-induced glutathione S-transferase genes from Triticum tauschii contribute to genome- and organ-specific expression in hexaploid wheat.

Glutathione S-transferase (GST) gene expression was examined in several Triticum species, differing in genome constitution and ploidy level, to determine genome contribution to GST expression in cultivated, hexaploid bread wheat (Triticum aestivum). Two tandemly duplicated tau class GST genes (TtGSTU1 and TtGSTU2) were isolated from a single bacterial artificial chromosome clone in a library constructed from the diploid wheat and D genome progenitor to cultivated wheat, Triticum tauschii. The genes are very similar in genomic structure and their encoded proteins are 95% identical. Gene-specific reverse transcriptase-polymerase chain reaction analysis revealed differential transcript accumulation of TtGSTU1 and TtGSTU2 in roots and shoots. Expression of both genes was induced by herbicide safeners, 2,4-dichlorophenoxyacetic acid and abscisic acid, in the shoots of T. tauschii; however, expression of TtGSTU1 was always higher than TtGSTU2. In untreated seedlings, TtGSTU1 was expressed in both shoots and roots, whereas TtGSTU2 expression was only detected in roots. RNA gel-blot analysis of ditelosomic, aneuploid lines that are deficient for 6AS, 6BS, or 6DS chromosome arms of cultivated, hexaploid bread wheat showed differential genome contribution to safener-induced GST expression in shoots compared with roots. The GST genes from the D genome of hexaploid wheat contribute most to safener-induced expression in the shoots, whereas GSTs from the B and D genomes contribute to safener-induced expression in the roots.