BackgroundRecent studies have demonstrated that long non-coding RNAs (lncRNAs) were present in the blood of cancer patients and have shown great potential as powerful and non-invasive tumor markers. However, little is known about the value of lncRNAs in the diagnosis of esophageal squamous cell carcinoma (ESCC). We hypothesized that ESCC-related lncRNAs might be released into the circulation during tumor initiation and could be utilized to detect and monitor ESCC.MethodsTen lncRNAs (HOTAIR, AFAP1-AS1, POU3F3, HNF1A-AS1, 91H, PlncRNA1, SPRY4-IT1, ENST00000435885.1, XLOC_013104 and ENST00000547963.1) which previously found to be differently expressed in esophageal cancer were selected as candidate targets for subsequent circulating lncRNA assay. A four-stage exploratory study was conducted to test the hypothesis: (1) optimization of detected method to accurately and reproducibly measure ESCC-related lncRNAs in plasma and serum; (2) evaluation of the stability of circulating lncRNAs in human plasma or serum; (3) exploration the origin of ESCC-related lncRNAs in vitro and in vivo; (4) evaluation the diagnostic power of circulating lncRNAs for ESCC.ResultsESCC-related lncRNAs were detectable and stable in plasma of cancer patients, and derived largely from ESCC tumor cells. Furthermore, plasma levels of POU3F3, HNF1A-AS1 and SPRY4-IT1 were significantly higher in ESCC patients compared with normal controls. By receiver operating characteristic curve (ROC) analysis, among the three lncRNAs investigated, plasma POU3F3 provided the highest diagnostic performance for detection of ESCC (the area under the ROC curve (AUC), 0.842; p < 0.001; sensitivity, 72.8%; specificity, 89.4%). Moreover, use of POU3F3 and SCCA in combination could provide a more effective diagnosis performance (AUC, 0.926, p < 0.001, sensitivity, 85.7%; specificity, 81.4%). Most importantly, this combination was effective to detect ESCC at an early stage (80.8%).ConclusionsPlasma POU3F3 could serve as a potential biomarker for diagnosis of ESCC, and the combination of POU3F3 and SCCA was more efficient for ESCC detection, in particular for early tumor screening.Electronic supplementary materialThe online version of this article (doi:10.1186/1476-4598-14-3) contains supplementary material, which is available to authorized users.

1. The role of endogenous nitric oxide (NO) generated by neuronal nitric oxide synthase (NOS_1) in the control of respiration during hypoxia and hypercapnia was assessed using mutant mice deficient in NOS_1. 2. Experiments were performed on awake and anaesthetized mutant and wild-type control mice. Respiratory responses to varying levels of inspired oxygen (100, 21 and 12% Oµ) and carbon dioxide (3 and 5% COµ balanced oxygen) were analysed. In awake animals, respiration was monitored by body plethysmograph along with oxygen consumption (ýOµ), COµ production (ýCOµ) and body temperature. In anaesthetized, spontaneously breathing mice, integrated efferent phrenic nerve activity was monitored as an index of neural respiration along with arterial blood pressure and blood gases. Cyclic 3',5'-guanosine monophosphate (cGMP) levels in the brainstem were analysed by radioimmunoassay as an index of nitric oxide generation. 3. Unanaesthetized mutant mice exhibited greater respiratory responses during 21 and 12% Oµ than the wild-type controls. Respiratory responses were associated with significant decreases in oxygen consumption in both groups of mice, and the magnitude of change was greater in mutant than wild-type mice. Changes in COµ production and body temperature, however, were comparable between both groups of mice. 4. Similar augmentation of respiratory responses during hypoxia was also observed in anaesthetized mutant mice. In addition, five of the fourteen mutant mice displayed periodic oscillations in respiration (brief episodes of increases in respiratory rate and tidal phrenic nerve activity) while breathing 21 and 12% Oµ, but not during 100% Oµ. The time interval between the episodes decreased by reducing inspired oxygen from 21 to 12% Oµ. 5. Changes in arterial blood pressure and arterial blood gases were comparable at any given level of inspired oxygen between both groups of mice, indicating that changes in these variables do not account for the differences in the response to hypoxia. 6. Respiratory responses to brief hyperoxia (Dejours test) and to cyanide, a potent chemoreceptor stimulant, were more pronounced in mutant mice, suggesting augmented peripheral chemoreceptor sensitivity. 7. cGMP levels were elevated in the brainstem during 21 and 12% Oµ in wild-type but not in mutant mice, indicating decreased formation of nitric oxide in mutant mice. 8. The magnitude of respiratory responses to hypercapnia (3 and 5% COµ balanced oxygen) was comparable in both groups of mice in the awake and anaesthetized conditions. 9. These observations suggest that the hypoxic responses were selectively augmented in mutant mice deficient in NOS-1. Peripheral as well as central mechanisms contributed to the altered responses to hypoxia. These results support the idea that nitric oxide generated by NOS_1 is an important physiological modulator of respiration during hypoxia.

BackgroundExpression of the long non-coding RNA (lncRNA) LOC285194 was previously shown to be correlated with aggressive clinicopathological features and poor prognosis in several cancers. The aim of the present study was to explore the relationship between LOC285194 expression and clinical outcomes in esophageal squamous cell carcinoma (ESCC), so as to assess whether it could be a novel biomarker for prognosis and prediction of response to therapy on ESCC patients.MethodsThe method of quantitative real-time polymerase chain reaction (qRT-PCR) was used to measure LOC285194 expression in pretreatment biopsy specimens and matched normal tissue derived from ESCC patients who underwent preoperative chemoradiotherapy followed by surgical resection (CRT + S group; n = 55) or from those who received surgical resection alone (S group; n = 87). The association between LOC285194 expression and clinicopathological features and prognosis were then analyzed.ResultsLOC285194 expression was significantly down-regulated in ESCC tumor tissues when compared with the adjacent normal tissues (p < 0.001). Low expression of LOC285194 was associated with larger tumor size (p = 0.002), advanced TNM stage (p = 0.018), more lymph node metastases (p = 0.013) and distant metastases (p = 0.015). In the CRT + S group, the pathological complete response rate was 57% (16/28) for the LOC285194-high group, and 15% (4/27) for the LOC285194-low group. Univariate analysis revealed that low expression of LOC285194 was significantly correlated with CRT response (p = 0.002). Moreover, Kaplan-Meier survival analysis revealed that patients with low expression of LOC285194 had a decreased disease free survival (DFS) (p < 0.001) and overall survival (OS) (p < 0.001). Multivariable analysis further identified low expression of LOC285194 as an independent prognosis factor for CRT response (p = 0.011), DFS (p < 0.001) and OS (p = 0.002).ConclusionDecreased expression of LOC285194 could serve as a molecular marker to predict the clinical outcome of ESCC patients after surgery, and select patients who would benefit from preoperative CRT.

Recent studies reveal that long noncoding RNAs (lncRNAs) play critical regulatory roles in cancer biology. Prostate cancer-associated ncRNA transcript 1 (PCAT-1) is one of the lncRNAs involved in cell apoptosis and proliferation of prostate cancer. This study aimed to assess the potential role of PCAT-1 specifically in the pathogenesis of esophageal squamous cell carcinoma (ESCC). Quantitative real-time polymerase chain reaction (qRT-PCR) was used to detect the expression level of PCAT-1 in matched cancerous tissues and adjacent noncancerous tissues from 130 patients with ESCC, 34 patients with non-small cell lung cancer (NSCLC), and 30 patients with gastric carcinoma (GC). The correlation of PCAT-1 with clinicopathological features and prognosis were also analyzed. The expression of PCAT-1 was significantly higher in human ESCC compared with the adjacent noncancerous tissues (70.8%, p < 0.01), and the high level of PCAT-1 expression was significantly correlated with invasion of the tumor (p = 0.024), advanced clinical stage (p = 0.003), lymph node metastasis (p = 0.032), and poor prognosis. However, PCAT-1 mRNA expression had no significant difference between paired primary cancerous tissues and the adjacent noncancerous tissues in 34 cases of NSCLC (p = 0.293) and 30 cases of GC (p = 0.125). High expression of PCAT-1 was specifically correlated with invasion of cancer tissues, metastasis of lymph node, and advanced tumor stage of ESCC. High expression of PCAT-1 might reflect poor prognosis of ESCC and indicate a potential diagnostic target in ESCC patients. Adjuvant therapy targeting PCAT-1 molecule might be effective in treatment of ESCC.

In the present study, the role of nitric oxide (NO) generated by endothelial nitric oxide synthase (NOS-3) in the control of respiration during hypoxia and hypercapnia was assessed using mutant mice deficient in NOS-3. Experiments were performed on awake and anesthetized mutant and wild-type (WT) control mice. Respiratory responses to 100, 21, and 12% O(2) and 3 and 5% CO(2)-balance O(2) were analyzed. In awake animals, respiration was monitored by body plethysmography along with O(2) consumption (VO(2)) and CO(2) production (VCO(2)). In anesthetized, spontaneously breathing mice, integrated efferent phrenic nerve activity was monitored as an index of neural respiration along with arterial blood pressure and blood gases. Under both experimental conditions, WT mice responded with greater increases in respiration during 12% O(2) than mutant mice. Respiratory responses to hyperoxic hypercapnia were comparable between both groups of mice. Arterial blood gases, changes in blood pressure, VO(2), and VCO(2) during hypoxia were comparable between both groups of mice. Respiratory responses to cyanide and brief hyperoxia were attenuated in mutant compared with WT mice, indicating reduced peripheral chemoreceptor sensitivity. cGMP levels in the brain stem during 12% O(2), taken as an index of NO production, were greater in mutant compared with WT mice. These observations demonstrate that NOS-3 mutant mice exhibit selective blunting of the respiratory responses to hypoxia but not to hypercapnia, which in part is due to reduced peripheral chemosensitivity. These results support the idea that NO generated by NOS-3 is an important physiological modulator of respiration during hypoxia.