The oncogenetic role of stanniocalcin 1 in lung adenocarcinoma: a promising serum candidate biomarker for tracking lung adenocarcinoma progression.

Stanniocalcin 1 (STC1) is reported to functionally participate in the development of several cancers. However, the role of STC1 in the tumorigenesis and progression of lung adenocarcinoma remains to be fully elucidated. Here, we found that the average levels of serum STC1 were 5.47, 5.53, and 6.94 ng/mL (P = 0.0045) in the healthy subjects and patients with lung adenocarcinoma at tumor stages I-II and III-IV according to Union for International Cancer Control (UICC), respectively. Subsequently, the positive correlation between the STC1 expression level in lung adenocarcinoma tissues and tumor stages was confirmed by immunohistochemical staining assay. Additionally, studies in the STC1-overexpressing or STC1-silenced stable cell lines showed that STC1 increased cell proliferation by promoting G1/S transition in cell cycle progression via up-regulating cyclin B1 and cyclin E. Moreover, studies in the STC1-overexpressing or STC1-silenced stable cell lines also showed that STC1 inhibited cell apoptosis by up-regulating the expression of anti-apoptosis proteins Bcl-2 and Bcl-xl and down-regulating the expression of pro-apoptosis proteins Bax, Bak, and Bid via the activation of the ERK and JNK signaling pathway. In addition, neutralization of STC1 with monoclonal antibody significantly increased the apoptosis of A549 cells. Taken together, our findings strongly suggest that elevated expression of STC1 protein at the III-IV stage of lung adenocarcinoma promotes tumorigenesis of lung adenocarcinoma and positively associates with the cancer progression, which may be of potential value as tumor marker in clinical tracking lung adenocarcinoma progression.

5-mRNA-based prognostic signature of survival in lung adenocarcinoma.

BACKGROUND: Lung adenocarcinoma (LUAD) is the most common non-small-cell lung cancer, with a high incidence and a poor prognosis. AIM: To construct effective predictive models to evaluate the prognosis of LUAD patients. METHODS: In this study, we thoroughly mined LUAD genomic data from the Gene Expression Omnibus (GEO) (GSE43458, GSE32863, and GSE27262) and the Cancer Genome Atlas (TCGA) datasets, including 698 LUAD and 172 healthy (or adjacent normal) lung tissue samples. Univariate regression and LASSO regression analyses were used to screen differentially expressed genes (DEGs) related to patient prognosis, and multivariate Cox regression analysis was applied to establish the risk score equation and construct the survival prognosis model. Receiver operating characteristic curve and Kaplan-Meier survival analyses with clinically independent prognostic parameters were performed to verify the predictive power of the model and further establish a prognostic nomogram. RESULTS: A total of 380 DEGs were identified in LUAD tissues through GEO and TCGA datasets, and 5 DEGs (TCN1, CENPF, MAOB, CRTAC1 and PLEK2) were screened out by multivariate Cox regression analysis, indicating that the prognostic risk model could be used as an independent prognostic factor (Hazard ratio = 1.520, P < 0.001). Internal and external validation of the model confirmed that the prediction model had good sensitivity and specificity (Area under the curve = 0.754, 0.737). Combining genetic models and clinical prognostic factors, nomograms can also predict overall survival more effectively. CONCLUSION: A 5-mRNA-based model was constructed to predict the prognosis of lung adenocarcinoma, which may provide clinicians with reliable prognostic assessment tools and help clinical treatment decisions.

The diagnostic value of circulating stanniocalcin-1 mRNA in non-small cell lung cancer.

BACKGROUND AND OBJECTIVES: Previous studies have suggested that the aberrant expression of Stanniocalcin-1 (STC1) occurs in tumor cells. In this study, we explored whether the circulating STC1 mRNA is a promising biomarker in the peripheral blood in patients with non-small cell lung cancer (NSCLC). METHODS: The level of circulating STC1 mRNA was determined with a sensitive quantitative real-time reverse transcription PCR assay. and the data were analyzed by the statistical methods of one-way ANOVA, Mann-Whitney-Wilcoxon U-Test, and Receiver operating characteristic (ROC) curve analysis. RESULTS: The level of circulating STC1 mRNA in patients with NSCLC was significantly higher than in patients with benign pulmonary disease (P < 0.001) or healthy volunteers (P < 0.001). Higher levels of circulating STC1 mRNA were associated with more advanced tumor stages and histological subtypes. Using a cutoff of 0.055, the sensitivity and specificity of STC1 mRNA levels to differentiate between patients with NSCLC and patients with benign pulmonary diseases was 66.7 and 90.9%, and it was 63.7 and 99.8% for patients with NSCLC and healthy volunteers, respectively. CONCLUSIONS: These findings support our hypothesis that circulating STC1 mRNA is a promising biomarker in the peripheral blood.

Daily oscillation and photoresponses of clock gene, Clock, and clock-associated gene, arylalkylamine N-acetyltransferase gene transcriptions in the rat pineal gland.

This study was conducted to investigate the circadian rhythms and light responses of Clock and arylalkylamine N-acetyltransferase (NAT) gene expressions in the rat pineal gland under the environmental conditions of a 12 h light (05:00-17:00 h): 12 h-dark (17:00-05:00 h) cycle (LD) and constant darkness (DD). The pineal gland of Sprague-Dawley rats housed under a LD regime (n=42) for four weeks and of a regime (n=42) for eight weeks were sampled at six different times, every 4 h (n=7 animals per time point), during a 24 h period. Total RNA was extracted from each sample, and the semiquantitative reverse transcription polymerase chain reaction (RT-PCR) was used to determine temporal changes in mRNA levels of Clock and NAT genes during different circadian or zeitgeber times. The data and parameters were analyzed by the cosine function software, Clock Lab software, and the amplitude F test was used to reveal the circadian rhythm. In the DD or LD condition, both the Clock and NAT mRNA levels in the pineal gland showed robust circadian oscillation (p<0.05) with the peak at the subjective night or at nighttime. In comparison with the DD regime, the amplitudes and mRNA levels at the peaks of Clock and NAT expressions in LD in the pineal gland were significantly reduced (p<0.05). In the DD or LD condition, the circadian expressions of NAT were similar in pattern to those of Clock in the pineal gland (p>0.05). These findings indicate that the transcriptions of Clock and NAT genes in the pineal gland not only show remarkably synchronous endogenous circadian rhythmic changes, but also respond to the ambient light signal in a reduced manner.

Circadian rhythms and different photoresponses of Clock gene transcription in the rat suprachiasmatic nucleus and pineal gland.

The aim of this study was to observe and compare the endogenous circadian rhythm and photoresponse of Clock gene transcription in the suprachiasmatic nucleus (SCN) and pineal gland (PG) of rats. With free access to food and water in special darkrooms, Sprague-Dawley rats were housed under the light regime of constant darkness (DD) for 8 weeks (n=36) or 12 hour-light: 12 hour-dark cycle (LD) for 4 weeks (n=36), respectively. Then, their SCN and PG were dissected out every 4 h in a circadian day, 6 rats at each time (n=6). All animal treatments and sampling during the dark phases were conducted under red dim light (<0.1 lux). The total RNA was extracted from each sample and the semi-quantitative RT-PCR was used to determine the temporal mRNA changes of Clock gene in the SCN and PG at different circadian times (CT) or zeitgeber times (ZT). The grayness ratio of Clock/H3.3 bands was served as the relative estimation of Clock gene expression. The experimental data were analyzed by the Cosine method and the Clock Lab software to fit original results measured at 6 time points and to simulate a circadian rhythmic curve which was then examined for statistical difference by the amplitude F test. The main results are as follows: (1) The mRNA levels of Clock gene in the SCN under DD regime displayed the circadian oscillation (P<0.05). The endogenous rhythmic profiles of Clock gene transcription in the PG were similar to those in the SCN (P>0.05) throughout the day with the peak at the subjective night (CT15 in the SCN or CT18 in the PG) and the trough during the subjective day (CT3 in the SCN or CT6 in the PG). (2) Clock gene transcription in the SCN under LD cycle also showed the circadian oscillation (P<0.05), and the rhythmic profile was anti-phasic to that under DD condition (P<0.05). The amplitude and the mRNA level at the peak of Clock gene transcription in the SCN under LD were significantly increased compared with that under DD (P<0.05), while the value of corresponding rhythmic parameters in the PG under LD were remarkably decreased (P<0.05). (3) Under LD cycle, the circadian profiles of Clock gene transcription induced by light in the PG were quite different from those in the SCN (P<0.05). Their Clock transcription rhythms were anti-phasic, i.e., showing peaks at the light phase ZT10 in the SCN or at the dark time ZT17 in the PG and troughs during the dark time ZT22 in the SCN or during the light phase ZT5 in the PG. The findings of the present study indicate a synchronous endogenous nature of the Clock gene circadian transcriptions in the SCN and PG, and different roles of light regime in modulating the circadian transcriptions of Clock gene in these two central nuclei.

[Circadian rhythms and light responses of clock gene and arylalkylamine N-acetyltransferase gene expressions in the pineal gland of rats].

This study was to investigate the circadian rhythms and light responses of Clock gene and arylalkylamine N-acetyltransferase (NAT) gene expressions in the rat pineal gland under the 12 h-light : 12 h-dark cycle condition (LD) and constant darkness (DD). Sprague-Dawley rats housed under the light regime of LD (n=36) for 4 weeks and of DD (n=36) for 8 weeks were sampled for the pineal gland once a group (n=6) every 4 h in a circadian day. The total RNA was extracted from each sample and the semiquantitative reverse transcription polymerase chain reaction (RT-PCR) was used to determine the temporal changes in mRNA levels of Clock and NAT genes during different circadian times or zeitgeber times. The data were analysed by the cosine function software, Clock Lab software and the amplitude F test was used to reveal the circadian rhythm. The main results obtained are as follows. (1) In DD or LD condition, both of Clock and NAT genes mRNA levels in the pineal gland showed robust circadian oscillation (P< 0.05) with the peak at the subjective night or at night-time. (2) In comparison with DD regime, the amplitudes and the mRNA levels at peaks of Clock and NAT genes expressions in LD in the pineal gland were significantly reduced (P< 0.05). (3) In DD or LD condition, the circadian expressions of NAT gene were similar in pattern to those of Clock gene in the pineal gland (P> 0.05). These findings suggest that the expressions of Clock and NAT genes in the pineal gland not only show remarkably synchronous endogenous circadian rhythmic changes, but also response to the ambient light signal in a reduced manner.

Circadian expression of clock and screening of clock-controlled genes in peripheral lymphocytes of rat.

In this paper, the circadian pattern of Clock and genes mediated by the Clock was investigated in peripheral lymphocytes of rats. Circadian rhythms of Clock are found under the regimes of constant darkness (DD) and 12-h light-12-h dark (LD12:12h), with the peak phase at CT7 and ZT21, respectively. Ten differential cDNA fragments were identified to be mediated by the Clock, including three known genes (catalase, myelin proteolipid protein, and histone acetylase), four known expressed sequence tags (ESTs), and three novel ESTs. Experiment of the RNA interference revealed that these ESTs were down-regulated by the Clock gene and three of them were identified as clock-controlled genes. Understanding of clock-mediated genes may lead to a new direction in drug design for control of circadian rhythms.