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Objective To explore the expression of Per2 in hepatocellular carcinoma (HCC) and its effect on the survival of HCC patients, and to analyze the effects of Per2 on the proliferation and apoptosis of SMMC-7721 cells. Methods The protein expression of Per2 in HCC patients was analyzed by immunohistochemical (IHC) staining. SMMC-7721 cells were transfected with Per2 eukaryotic expression plasmid. The protein expression of Per2 was detected by Western blot. The cell proliferation and apoptosis was detected by MTS and flow cytometry. Results In 117 HCC tissues, the Per2 positive expression rate was 70. 94%, which was significantly lower than that of 87. 18% in the adjacent HCC tissue. The Per2 staining score was 2. 14±1. 76, which was significantly lower than that of 6. 39±3. 84 in the adjacent HCC tissue (P<0. 01). Per2 expression was related to tumor diameter, portal vein invasion and TNM staging(P<0.05) in 117 HCC patients. The overall survival (OS) and recurrence-free survival (RFS) of HCC pa-tients with low expression of Per2 were shorter than those with Per2 high expression(P<0.05).The cell proliferation was significantly inhibited and the apoptosis increased with the transfection of Per2 eukaryotic expression plasmid in SMMC-7721 cells(P<0.05).Conclusions The expression of Per2 in HCC is significantly reduced.Per2 inhibits the progression of HCC,possibly by inhibiting cell proliferation and promoting apoptosis.
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Most organisms have adapted to a circadian rhythm that follows a roughly 24-hour cycle, which is modulated by both internal (clock-related genes) and external (environment) factors. In such organisms, the central nervous system (CNS) is influenced by the circadian rhythm of individual cells. Furthermore, the period circadian clock 2 (Per2) gene is an important component of the circadian clock, which modulates the circadian rhythm. Per2 is mainly expressed in the suprachiasmatic nucleus (SCN) of the hypothalamus as well as other brain areas, including the midbrain and forebrain. This indicates that Per2 may affect various neurobiological activities such as sleeping, depression, and addiction. In this review, we focus on the neurobiological functions of Per2, which could help to better understand its roles in the CNS.
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Brain , Central Nervous System , Circadian Clocks , Circadian Rhythm , Depression , Hypothalamus , Mesencephalon , Neurotransmitter Agents , Prosencephalon , Suprachiasmatic NucleusABSTRACT
OBJECTIVE: To observe the effect of electroacupuncture (EA) on the rhythm of running-wheel activity of hepatocellular carcinoma (HCC) mice and the expression of Per 1 and Per 2 (circadian rhythm genes) in the hypothalamic suprachiasmatic nucleus (SCN), so as to investigate its mechanism underlying regulating circadian rhythm. METHODS: A total of 108 male C 57 BL / 6 J mice were randomly divided into control, HCC model and EA groups which were further assigned to six zeitbeger (environmental light-dark cycle) time (ZT) point (ZT 0, ZT 4, ZT 8, ZT 12, ZT 16 and ZT 20) subgroups. The HCC model was established by injection of H 22 cancer cell (abdominal 3rd generation, 10 µL) suspension into the larger live lobe. Mice of the control group received saline injection of the liver lobe. EA (2 Hz/15 Hz, 0.2 mA) was applied to bilateral "Ganshu" (BL 18) and "Zhiyang" (GV 9) for 15 min, once daily for 10 days. Mice of the control and model groups received the same binding-fixing to those of the EA group. Circadian running-wheel activity of 12 h∶12 h light darkness (LD) cycle (activity onset and acrophase of actogram, amplitude or peak of periodogram) was recorded by using ClockLab (ACT-500) software and analyzed by MATLAB (R 2007 b) before and after EA treatment. The pathological changes of liver cells were observed under light microscope after sectioning and H．E. staining. The expression levels of Per 1 mRNA and Per 2 mRNA in the liver tissues were determined by fluorogenic quantitative real time-PCR. RESULTS: (1) Following modeling, the amplitude of periodogram of running-wheel activity was significantly lowered at ZT 0, ZT 4, ZT 8, ZT 12, ZT 16, and ZT 20 relevant to the control group (P0.05). (2) The expression levels of Per 1 mRNA and Per 2 mRNA in the SCN were significantly up-regulated at the 6 time-points in the model group relevant to the control group (P<0.05), and obviously down-regulated at ZT 8 after EA intervention relevant to the model group (P<0.05)．. CONCLUSION: EA can benignly regulate the rhythm of running-wheel activity of HCC mice, which may be closely related to its effect in down-regulating the expression of circadian rhythm genes Per 1 and Per 2 in the SCN.
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Objective To find the effect of alter-expressed PER2 on proliferation,apoptosis and other clock genes expression in human oral squamous cell carcinoma SCC15 cells.Methods Short hairpin RNA interference was used to knockdown PER2 in SCC15 human oral squamous cell carcinoma cells.Flow cytometry analysis was used to testify the cell proliferation and apoptosis.Quantitative real-time PCR was used to testify the mRNA expressions of PER3,BMAL1,DEC1,DEC2,CRY2,TIM,RORα,NPAS2,PER1 and REV-ERBα.Results The proliferation was enhanced and apoptosis was decreased after PER2 knockdown in SCC15 cells (P<0.05).The mRNA expression of PER3,BMAL1,DEC1,DEC2,CRY2,TIM,RORα and NPAS2 was significantly down-regulated,and the mRNA expression of PER1 and REV-ERBα was significantly up-regulated (P<0.05).Conclusions Clock gene PER2 plays an important role in regulating other clock genes of the clock gene network in cancer cells,PER2 knockdown can enhance proliferation and recede apoptosis of cancer cell.
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BACKGROUND: In mammals, the master circadian pacemaker is localized in an area of the ventral hypothalamus known as the suprachiasmatic nucleus (SCN). Previous studies have shown that pacemaker neurons in the SCN are highly coupled to one another, and this coupling is crucial for intrinsic self-sustainability of the SCN central clock, which is distinguished from peripheral oscillators. One plausible mechanism underlying the intercellular communication may involve direct electrical connections mediated by gap junctions. METHODS: We examined the effect of mefloquine, a neuronal gap junction blocker, on circadian Period 2 (Per2) gene oscillation in SCN slice cultures prepared from Per2::luciferase (PER2::LUC) knock-in mice using a real-time bioluminescence measurement system. RESULTS: Administration of mefloquine causes instability in the pulse period and a slight reduction of amplitude in cyclic PER2::LUC expression. Blockade of gap junctions uncouples PER2::LUC-expressing cells, in terms of phase transition, which weakens synchrony among individual cellular rhythms. CONCLUSION: These findings suggest that neuronal gap junctions play an important role in synchronizing the central pacemaker neurons and contribute to the distinct self-sustainability of the SCN master clock.
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Animals , Mice , Circadian Rhythm , Electrical Synapses , Gap Junctions , Hypothalamus , Luminescent Measurements , Mammals , Mefloquine , Neurons , Phase Transition , Suprachiasmatic NucleusABSTRACT
@#Per2 gene plays one of the most critical roles of clock gene which modulates circadian rhythm both in the physiological, biochemical and behavioral processes of organisms. The distributions of per2 gene include suprachiasmatic nucleus of the hypothalamus, central nucleus of amygdala, bed nucleus of the stria terminalis, hippocampus and other components of limbic system; it affects the emotional and visceral activities through participating in the system of circadian rhythm. The central per2 gene regulates the hypothalamus-pituitaryadrenal axis through integration of light input, steroid hormones and other neurotransmitters integration, acting on the target organs, and presentes a circadian rhythm of movement. This article reviewed the morphology and biology of per2 gene, and its participation in limbic system regulating the circadian rhythm of motional and visceral activities.
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Objective To explore the prognosis related genes of pancreatic ductal adenocarcinoma (PDAC)and investigate the molecular regulation mechanism.Methods Gene expression data of 102 PDAC patients with complete clinical survival data were selected from gene expression database of National Center for Biotechnology Information.The 106 transcription regulation gene collection was collected from Transfac database.The 715 microRNA (miRNA)target regulation gene collection was selected according to PicTar and TargetScanS method.Biological pathway data obtained from the Kyoto Encyclopedia of Genes and Genomes (KEGG).The known cancer genes were collected from the cancer gene census (CGC) database.Univariate Cox proportional hazards model was used to analyze the correlation between gene expression data and survival time,then obtained survival related candidate genes from the whole genome. Then the enriched genes were analyzed by hypergeometric distribution algorithm from three databases. Multiple correction testing was performed by BH-FDR method (FDR < 0.05 ).Kaplan-Meier was performed for survival curve analysis of PDAC.Results The results of data of 102 PDAC patients analyzed by univariate Cox proportional hazards model indicated that 273 genes were significantly related to the survival time of patients (P <0.000 1 ).After 273 survival genes were enrichment analyzed in 106 transcription factor regulation gene collection,12 survival genes enriched transcription factor target gene sets were found.After 273 survival genes were enrichment analyzed in 715 miRNA target regulation gene collection,11 survival genes enriched miRNAs target sets were discovered.After 273 survival genes were enrichment analyzed in pathway data of KEGG,15 survival genes enriched pathways were obtained. Period circadian clock 2 (PER2 )was regulated by CCAAT/enhancer binding protein (CEBPA)at transcription level and regulated by miRNA-32 after transcription.The prognosis of PDAC was affected by circadian rhythm pathway.The 102 patients with PDAC were ranked according to the expression of PER2 from high to low,the first 51 cases were included in PER2 higher expression group and the left were included in PER2 lower expression group.Kaplan-Meier survival analysis indicated that PER2 was significantly correlated with prognosis of PDAC (P <0.01 ).Conclusion CEBPA/miRNA-32/PER2 and its related circadian clock pathway may be the target pathway in interfering the development of PDAC,and is correlated with the prognosis of PDAC.
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Vertebrates have a central clock and also several peripheral clocks. Light responses might result from the integration of light signals by these clocks. The dermal melanophores of Xenopus laevis have a photoreceptor molecule denominated melanopsin (OPN4x). The mechanisms of the circadian clock involve positive and negative feedback. We hypothesize that these dermal melanophores also present peripheral clock characteristics. Using quantitative PCR, we analyzed the pattern of temporal expression of Opn4x and the clock genes Per1, Per2, Bmal1, and Clock in these cells, subjected to a 14-h light:10-h dark (14L:10D) regime or constant darkness (DD). Also, in view of the physiological role of melatonin in the dermal melanophores of X. laevis, we determined whether melatonin modulates the expression of these clock genes. These genes show a time-dependent expression pattern when these cells are exposed to 14L:10D, which differs from the pattern observed under DD. Cells kept in DD for 5 days exhibited overall increased mRNA expression for Opn4x and Clock, and a lower expression for Per1, Per2, and Bmal1. When the cells were kept in DD for 5 days and treated with melatonin for 1 h, 24 h before extraction, the mRNA levels tended to decrease for Opn4x and Clock, did not change for Bmal1, and increased for Per1 and Per2 at different Zeitgeber times (ZT). Although these data are limited to one-day data collection, and therefore preliminary, we suggest that the dermal melanophores of X. laevis might have some characteristics of a peripheral clock, and that melatonin modulates, to a certain extent, melanopsin and clock gene expression.
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Animals , CLOCK Proteins/metabolism , Melanophores/physiology , Melatonin/pharmacology , Rod Opsins/metabolism , ARNTL Transcription Factors/genetics , ARNTL Transcription Factors/metabolism , CLOCK Proteins/genetics , Circadian Clocks/drug effects , Circadian Clocks/genetics , Circadian Clocks/physiology , Eye Proteins/genetics , Eye Proteins/metabolism , Melanophores/drug effects , Polymerase Chain Reaction , Period Circadian Proteins/genetics , Period Circadian Proteins/metabolism , RNA, Messenger , Rod Opsins/drug effects , Xenopus laevis , Xenopus Proteins/genetics , Xenopus Proteins/metabolismABSTRACT
Objective To detect the expression of Per2 and VEGF in NSCLC tissue,and analyze its clinical significance.Methods The expression of Per2 and VEGF was measured in 60 NSCLC and 20 normal lung tissue by immunohistochemistry assay,then the relation with clinicopathological parameters was analyzed.Results The positive expression rate of Per2 in NSCLC and in normal lung tissue were 71.7％ and 95.0％ ( x2 =4.683,P ＜0.05 ),while the positive expression rate of VEGF were 58.3％ and 15％ (x2 =11.295,P ＜ 0.01 ).The negative expression of Per2 in NSCLC was correlated with pathological differentiation or TNM stage( x2 =4.413,6.179,all P ＜0.05),while the positive expression of VEGF in NSCLC was correlated with pathological differentiation or lymphatic metastasis (x2 =6.524,P ＜ 0.05 ).The expression of Per2 was negatively correlated with the expression of VEGF in NSCLC (r =-0.381,P ＜ 0.01 ).Conclusion The overexpression of VEGF in NSCLC may contribute to invasion and metastasis,while Per2 may be a beneficial prognosis factor in patients with NSCLC.