Adenosine A(2A)R modulates cardiovascular function by activating ERK1/2 signal in the rostral ventrolateral medulla of acute myocardial ischemic rats

Adenosine A2A receptors in the rostral ventrolateral medulla participate in blood pressure decrease with electroacupuncture in hypertensive rats

Acupuncture is increasingly used to manage high blood pressure (BP) as a complementary therapy. However, the mechanisms underlying its hypotensive effects remain unclear. Our previous studies have shown that electroacupuncture (EA) at the ST36-37 acupoints, overlying the deep peroneal nerve, attenuates pressor responses through adenosine A2A receptors (A2AR) in the rostral ventrolateral medulla (rVLM). However, it is uncertain whether rVLM A2AR contributes to EA's BP-lowering effect in sustained hypertension. We hypothesized that a course of EA treatment lowers BP, in part, through the activation of adenosine A2AR in the rVLM in hypertensive rats. To mimic essential hypertension in the clinic, we performed EA in conscious Dahl salt-sensitive hypertensive rats (DSHRs). EA (0.1-0.4 mA, 2 Hz) was applied at ST36-37 for 30 min twice weekly for four weeks, while sham-EA was conducted in a similar manner but without electrical input. In hypertensive rats, BP was reduced by EA (n = 14) but neither by sham-EA (n = 14) nor in the absence of needling (n = 8). Following four weeks of eight treatments and then under anesthesia, EA's modulatory effect on elevated BP was reversed by unilateral rVLM microinjection of SCH 58261 (1 mM in 50 nl; an A2AR antagonist; n = 7; P < 0.05) but not the vehicle (n = 5) in EA-treated DSHRs. Activation of rVLM A2AR in DSHRs treated with sham-EA by an A2AR agonist, CGS-21680 (0.4 mM in 50 nl; n = 8), decreased BP. Unilateral administration of SCH 58261 or CGS-21680 into the rVLM did not alter basal BP in Dahl salt-sensitive rats fed a regular diet with normal BP. The A2AR level in the rVLM after EA was increased compared to the sham-EA and untreated DSHRs (n = 5 in each group; all P < 0.05). These data suggest that a 4-week twice weekly EA treatment reduced BP in salt-sensitive hypertensive rats likely through adenosine-mediated A2AR in the rVLM.

Role of Cardiac A2A Receptors Under Normal and Pathophysiological Conditions

This review presents an overview of cardiac A2A-adenosine receptors The localization of A2A-AR in the various cell types that encompass the heart and the role they play in force regulation in various mammalian species are depicted. The putative signal transduction systems of A2A-AR in cells in the living heart, as well as the known interactions of A2A-AR with membrane-bound receptors, will be addressed. The possible role that the receptors play in some relevant cardiac pathologies, such as persistent or transient ischemia, hypoxia, sepsis, hypertension, cardiac hypertrophy, and arrhythmias, will be reviewed. Moreover, the cardiac utility of A2A-AR as therapeutic targets for agonistic and antagonistic drugs will be discussed. Gaps in our knowledge about the cardiac function of A2A-AR and future research needs will be identified and formulated.

Adenosine Receptor A2a, but Not A1 in the rVLM Participates Along With Opioids in Acupuncture-Mediated Inhibition of Excitatory Cardiovascular Reflexes

Electroacupuncture (EA) can be used to lower high blood pressure (BP) in clinical practice. However, precise mechanisms underlying its effects on elevated BP remain unclear. Our previous studies have shown that EA at the P5-6 acupoints, overlying the median nerve, attenuates elevated BP induced by gastric distension (GD) through influence on rostral ventrolateral medulla (rVLM). Although adenosine is released during neuronal activation in the rVLM, its role in acupuncture-cardiovascular regulation is unknown. The purinergic system is involved in cardiovascular pressor and depressor responses, including via selective activation of A₁ and A_{2 a} rVLM receptors, respectively. The action of A_{2 a} receptor stimulation in the central nervous system may be further regulated through an endogenous opioid mechanism. However, it is uncertain whether this putative action occurs in the rVLM. We hypothesized that adenosine in the rVLM contributes to EA modulation of sympathoexcitatory reflexes through an A_{2 a} but not an A₁ adenosine receptor-opioid mechanism. EA or sham-EA was applied at the P5-6 acupoints in Sprague-Dawley male rats subjected to repeated GD under anesthesia. We found that EA (n = 6) but not sham-EA (n = 5) at P5-6 significantly (P < 0.05) attenuated GD-induced elevations in BP. EA modulation of sympathoexcitatory cardiovascular reflexes was reversed significantly after rVLM microinjection (50 nl) of 8-SPT (10 mM; non-selective adenosine receptor antagonist; n = 7) or SCH 58261 (1 mM; A_{2 a} receptor antagonist; n = 8; both P < 0.05), but not by DPCPX (3 mM; A₁ receptor antagonist; n = 6) or the vehicle (5% dimethylsulfoxide; n = 6). Moreover, microinjection of an A_{2 a} receptor agonist, CGS-21680 (0.4 mM; n = 8) into the rVLM attenuated GD-induced pressor responses without EA, which mimicked EA's inhibitory effects (P < 0.05). After blockade of opioid receptors with naloxone (1 mM) in the rVLM, SCH 58261's reversal of EA's effect on GD-induced pressor responses was blunted, and CGS-21680-mediated inhibitory effect on pressor responses was not observed. Furthermore, neurons labeled with adenosine A_{2 a} receptors were anatomically co-localized with neurons stained with enkephalin in the rVLM. These data suggest that the involvement of rVLM adenosine A_{2 a} receptors in EA modulation of GD-induced pressor reflexes is, at least in part, dependent on the presence of endogenous opioids.

Central blockade of the AT1 receptor attenuates pressor effects via reduction of glutamate release and downregulation of NMDA/AMPA receptors in the rostral ventrolateral medulla of rats with stress-induced hypertension

Glutamatergic activity in the rostral ventrolateral medulla (RVLM), which is an important brain area where angiotensin II (Ang II) elicits its pressor effects, contributes to the onset of hypertension. The present study aimed to explore the effect of central Ang II type 1 receptor (AT₁R) blockade on glutamatergic actions in the RVLM of stress-induced hypertensive rats (SIHR). The stress-induced hypertension (SIH) model was established by electric foot shocks combined with noises. Normotensive Sprague-Dawley rats (control) and SIHR were intracerebroventricularly infused with the AT₁R antagonist candesartan or artificial cerebrospinal fluid for 14 days. Mean arterial pressure (MAP), heart rate (HR), plasma norepinephrine (NE), glutamate, and the expression of N-methyl-D-aspartic acid (NMDA) receptor subunit NR1, and α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptors in the RVLM increased in the SIH group. These increases were blunted by candesartan. Bilateral microinjection of the ionotropic glutamate receptor antagonist kynurenic acid, the NMDA receptor antagonist D-2-amino-5-phosphonopentanoate, or the AMPA/kainate receptors antagonist 6-cyano-7-nitroquinoxaline-2,3-dione into the RVLM caused a depressor response in the SIH group, but not in other groups. NR1 and AMPA receptors expressed in the glutamatergic neurons of the RVLM, and glutamate levels, increased in the intermediolateral column of the spinal cord of SIHR. Central Ang II elicits release of glutamate, which binds to the enhanced ionotropic NMDA and AMPA receptors via AT₁R, resulting in activation of glutamatergic neurons in the RVLM, increasing sympathetic excitation in SIHR.

Neuroinflammation contributes to autophagy flux blockage in the neurons of rostral ventrolateral medulla in stress-induced hypertension rats

BACKGROUND

Neuroinflammation plays hypertensive roles in the uninjured autonomic nuclei of the central nervous system, while its mechanisms remain unclear. The present study is to investigate the effect of neuroinflammation on autophagy in the neurons of the rostral ventrolateral medulla (RVLM), where sympathetic premotor neurons for the maintenance of vasomotor tone reside.

METHODS

Stress-induced hypertension (SIH) was induced by electric foot-shock stressors with noise interventions in rats. Systolic blood pressure (SBP) and the power density of the low frequency (LF) component of the SAP spectrum were measured to reflect sympathetic vasomotor activity. Microglia activation and pro-inflammatory cytokines (PICs (IL-1β, TNF-α)) expression in the RVLM were measured by immunoblotting and immunostaining. Autophagy and autophagic vacuoles (AVs) were examined by autophagic marker (LC3 and p62) expression and transmission electron microscopy (TEM) image, respectively. Autophagy flux was evaluated by RFP-GFP-tandem fluorescent LC3 (tf-LC3) vectors transfected into the RVLM. Tissue levels of glutamate, gamma aminobutyric acid (GABA), and plasma levels of norepinephrine (NE) were measured by using high-performance liquid chromatography (HPLC) with electrochemical detection. The effects of the cisterna magna infused minocycline, a microglia activation inhibitor, on the abovementioned parameters were analyzed.

RESULTS

SIH rats showed increased SBP, plasma NE accompanied by an increase in LF component of the SBP spectrum. Microglia activation and PICs expression was increased in SIH rats. TEM demonstrated that stress led to the accumulation of AVs in the RVLM of SIH rats. In addition to the Tf-LC3 assay, the concurrent increased level of LC3-II and p62 suggested the impairment of autophagic flux in SIH rats. To the contrary, minocycline facilitated autophagic flux and induced a hypotensive effect with attenuated microglia activation and decreased PICs in the RVLM of SIH rats. Furthermore, SIH rats showed higher levels of glutamate and lower level of GABA in the RVLM, while minocycline attenuated the decrease in GABA and the increase in glutamate of SIH rats.

CONCLUSIONS

Collectively, we concluded that the neuroinflammation might impair autophagic flux and induced neural excitotoxicity in the RVLM neurons following SIH, which is involved in the development of SIH.

The protective effects of electro-acupuncture in thoracic surgery on trauma stressed rats involve the rostral ventrolateral medulla and supraoptic nucleus

The present study was designed to explore whether the rostral ventrolateral medulla (RVLM) and supraoptic nucleus (SON) were involved in the protective effects of electro-acupuncture (EA) in thoracic surgery on trauma-stressed rats. The rats were randomly divided into a non-stressed group (Control), surgical trauma-stressed group (Trauma), and Neiguan EA applied on the surgical trauma-stressed group (Trauma+EA-PC 6). RVLM neuron discharge was observed by using an in vivo electrophysiological method, and micro-dialysis combining high-performance liquid chromatography with fluorometric detection (HPLC-FD) was used to assess expression of amino acids in the RVLM. Immunohistochemical methods were used to assess c-Fos expression in SON neurons. The trauma of surgical stress was shown to dramatically increase the discharge frequency of RVLM neurons and promote the release of glutamate and taurine in the RVLM. The expression of c-Fos was also significantly increased in the SON of traumatized rats. EA application at Neiguan acupoints significantly suppressed trauma-induced increase of discharge frequency of the RVLM neurons, almost completely suppressed the trauma-induced increase of glutamate release but only very slightly reduced the trauma-enhanced taurine release, and inhibited the increase of c-Fos expression in these SON neurons of traumatized rats. These results indicate that Neiguan EA may improve cardiac function by modulating neurons in the RVLM and the SON in surgically traumatized rats. The taurine-mediated negative feedback may be involved in the protective effect of EA on cardiac function.

[Comprehensive Identification of MicroRNAs Regulated by Long Non-coding RNA MALAT1]

BACKGROUND

Long non-coding RNA (lncRNA) plays important regulatory roles in the development and invasion of various cancers. The aim of current study is to comprehensively identify microRNAs (miRNA) regulated by lncRNA MALAT1 via experimental and bioinformatics methods.

METHODS

Antisense oligonucleotides (ASO) specifically targeting MALAT1 were designed and synthesized. After knockdown of MALAT1 by ASO in A549 cells, miRNA expression changes were profiled by TqaMan Low Density Array (TLDA). Gene set enrichment analysis (GSEA) was used to search enriched miRNAs among differentially expressed genes after knockdown of MALAT1.

RESULTS

After efficient knockdown of MALAT1 by ASO, 153 miRNAs were differentially expressed, 131 up-regulated and 22 down-regulated. Among the 458 differentially expressed genes after MALAT1 silence, GSEA results revealed lots of enriched miRNAs. There were 28 overlapped miRNAs between TLDA and GSEA results, suggesting these 28 miRNAs are regulated by MALAT1.

CONCLUSIONS

This study comprehensively identified MALAT1 regulated miRNAs, providing resources for further research.

[Hsp90AB1 Protein is Overexpressed in Non-small Cell Lung Cancer Tissues and Associated with Poor Prognosis in Lung Adenocarcinoma Patients]

BACKGROUND

Heat shock protein 90 kDa alpha, class B member 1 (Hsp90AB1) is highly conserved ATP-dependent molecular chaperone, and over-expressed in a variety of tumor cells. Some molecules that play important roles in tumor development signaling pathways such as epidermal growth factor receptor (EGFR), human epidermal growth factor receptor-2 (HER2) are Hsp90AB1 client proteins. Hsp90AB1 interact with these client proteins and participate in a variety of pathophysiological processes of cells. The aim of this study is to detect the expression of Hsp90AB1 in non-small cell lung cancer (NSCLC) tissues, and explore its clinical significance.

METHODS

The expression of Hsp90AB1 in 213 NSCLC tissues and 147 normal lung tissues was detected by tissue microarray and immunohistochemical staining method, and the relationship of Hsp90AB1 expression with clinicopathological parameters and prognosis of NSCLC patients were analyzed.

RESULTS

The expression level of Hsp90AB1 in lung cancer tissues (positive rate of 54.0%) was significantly higher than that in normal lung tissue (positive rate of 0.0%, P<0.001). The positive expression rate of Hsp90AB1 in lung adenocarcinoma tissues (61.2%) was significantly higher than that in lung squamous cell carcinoma tissues (37.9%)(P=0.002), and its over-expression was associated with poor prognosis in lung adenocarcinoma patients (P=0.032). The expression level of Hsp90AB1 had no significant correlation with clinical stage, lymph node metastasis, pathological grade or other factors (P>0.05).

CONCLUSIONS

Hsp90AB1 protein was over-expressed in NSCLC tissues, and was associated with lung cancer pathological type and overall survival in lung adenocarcinoma patients.

[SIRT1 Influences the Sensitivity of A549 Non-small Cell Lung Cancer Cell Line to Cisplatin via Modulating the Noxa Expression]

背景与目的

非小细胞肺癌的顺铂耐药是常见的临床现象，严重制约了患者的化疗效果，是亟待解决的问题。SIRT1和Noxa的表达变化影响肿瘤细胞对化疗药物的敏感性。本研究旨在研究SIRT1表达对非小细胞肺癌对顺铂的敏感性的影响，并探讨其涉及Noxa表达的机制，以求为提高非小细胞肺癌细胞对顺铂敏感性提供希望。

方法

利用实时荧光定量PCR和Western blot分析A549细胞及顺铂耐药的A549/DDP细胞SIRT1及Noxa mRNA和蛋白水平的表达差异。利用siRNA干扰技术抑制A549/DDP细胞的SIRT1表达，进而使用Cell Titer Blue试验、流式细胞术从细胞增殖、细胞周期和细胞凋亡方面分析SIRT1沉默对A549/DPP细胞顺铂敏感性的影响。同时利用实时荧光定量PCR和Western blot分析SIRT1抑制对A549/DPP细胞Noxa表达的影响。

结果

A549细胞和A549/DDP细胞对顺铂的敏感性有显著差异，与A549细胞相比，A549/DDP细胞的SIRT1表达较高，但Noxa表达较低。使用siRNA抑制A549/DPP细胞的SIRT1表达后，与未抑制SIRT1细胞相比，4 μg/mL顺铂处理后的细胞存活率降低，G2期/M期阻滞比例增加，凋亡率提高。同时，SIRT1沉默导致A549/DPP细胞的Noxa表达增加。

结论

较高的SIRT1可能引起A549细胞对顺铂的耐药性，抑制SIRT1可以提高A549/DDP细胞对顺铂的敏感性，其机制可能涉及SIRT1对Noxa的调节。

[Influence of Immunohistochemistry Scoring Criteria in Detecting EGFR Mutations]

背景与目的

恰当的免疫组化染色评分可确保突变检测结果的可靠性，目前大多数研究认为“四分法”是所有评分系统中最佳的方法。本研究旨在探讨不同四分法染色评分对检测结果的影响。

方法

用三种不同的四分法免疫组化染色评分标准评价83例非小细胞肺癌标本表皮生长因子受体（epidermal growth factor receptor, EGFR）突变情况，并以液相芯片法作为金标准进行比较，计算每种方法的灵敏度、特异度、阳性预测值（positive predictive value, PPV）、阴性预测值（negative predictive value, NPV）、与金标准间一致度及三种标准间是否存在统计学差异。

结果

三种标准在检测EGFR突变方面不存在统计学差异，每种标准检测结果的特异度均明显优于灵敏度。染色为“3+”的标本，PPV均可高达100%。

结论

不同的四分法评分没有绝对的最佳标准，但无论用何种标准，免疫组化法（immunohistochemistry, IHC）检测EGFR突变的特异度均明显优于灵敏度。评分为“3+”的标本，可认为实际确实存在突变，直接接受EGFR酪氨酸激酶抑制剂（tyrosine kinase inhibitor, TKI）治疗。

[Effect of TRAF6 Downregulation on Malignant Biological Behavior of Lung Cancer Cell Lines]

背景与目的

已有的研究提示肿瘤坏死因子受体相关因子6(tumor necrosis factor receptor-associated factor 6, TRAF6)在肺癌中常常扩增，可能扮演癌基因角色，但TRAF6的确切作用尚未充分阐明。本研究探索TRAF6表达对肺癌细胞株的增殖、凋亡、细胞周期、迁移及侵袭能力的影响以及可能作用机制。

方法

选用A549、H1650、SPC-A-1以及Calu-3等四种肺癌细胞株，应用蛋白印迹、qRT-PCR检测其TRAF6蛋白及mRNA表达。SPC-A-1、Calu-3细胞转染TRAF6 siRNA，以EMSA方法检测不同处理组核因子-κB的DNA结合活性，MTS法检测细胞增殖，流式细胞仪PI染色检测细胞凋亡，流式细胞仪进行细胞周期测定，划痕实验及Transwell小室法检测细胞迁移及侵袭能力，并应用蛋白印迹检测泛素化抗体、p65、CD24、CXCR4等蛋白表达。SPC-A-1细胞提取DNA后，应用二代测序法进行全基因组测序。

结果

在四种细胞株中，SPC-A-1和Calu-3细胞TRAF6相对高表达，TRAF6发生自身K63-泛素化，但仅在SPC-A-1细胞中观察到核因子-κB组成性活化。转染TRAF6 siRNA后，SPC-A-1、Calu-3细胞TRAF6表达明显下调，与空白组及对照组相比，下调TRAF6表达可抑制SPC-A-1细胞核因子-κB活性、降低迁移及侵袭能力以及促进细胞凋亡，CD24和CXCR4的表达也明显下调，但对细胞增殖及细胞周期无明显影响。下调TRAF6表达对Calu-3细胞株的核因子-κB活性、细胞增殖、凋亡、细胞周期、迁移及侵袭能力等均无明显影响。未发现SPC-A-1细胞株TRAF6基因突变或拷贝数改变。

结论

下调TRAF6表达可抑制SPC-A-1细胞迁移及侵袭能力，促进细胞凋亡，并且TRAF6可能是通过调控核因子-κB-CD24/CXCR4信号通路参与调控肺癌侵袭、细胞凋亡。

[Detection and Analysis of EGFR and KRAS Mutation with Lung Adenocarcinoma]

背景与目的

表皮生长因子受体(epidermal growth factor receptor, EGFR)突变和KRAS基因突变是非小细胞肺癌(non-small cell lung cancer, NSCLC)靶向治疗的重要分子标志，与临床治疗疗效密切相关。分析肺腺癌EGFR和KRAS基因突变与临床特征的关系。

方法

收集初治肺腺癌患者395例，有可供检测的肿瘤组织标本。利用突变富集液相芯片法进行EGFR和KRAS基因突变检测。

结果

395例肺腺癌中，EGFR基因突变192例(48.9%)，KRAS基因突变29例(7.8%)，EGFR和KRAS基因同时发生突变1例(0.3%)。女性和不吸烟患者EGFR基因突变率高于男性和吸烟患者(62.0% vs 37.1%, 61.9% vs 30.3%)，差异具有统计学意义(P＜0.001, P＜0.001)；不同年龄、分期及病理取材标本之间差异均无统计学意义(P＞0.05)。KRAS基因突变在EGFR基因野生型患者中发生率(13.5%, 27/200)明显高于EGFR基因突变患者(1.0%, 2/192)，差异具有统计学意义(P＜0.001)。

结论

肺腺癌EGFR基因突变在女性和不吸烟患者中较高，KRAS基因突变只在EGFR基因野生型患者中较高。在使用TKI靶向治疗药物之前，应同时检测EGFR基因和KRAS基因的突变情况。

[Ionizing Radiation Reduces TKI Resistance Caused by T790M Mutation in NSCLC Cell Lines]

背景与目的

以表皮生长因子受体（epidermal growth factor receptor, EGFR）为靶点的分子靶向治疗在非小细胞肺癌（non-small cell lung cancer, NSCLC）的治疗中发挥重要的作用。EGFR突变的患者对EGFR酪氨酸激酶抑制剂（EGFR-tyrosine kinase inhibitor, EGFR-TKI）治疗敏感、疗效显著，但无论近期疗效如何，患者最终都不可避免地产生耐药。大量研究证实，EGFR基因的二次突变（T790M）是患者耐药的主要原因。本研究旨在探讨电离辐射对NSCLC细胞株T790M突变所致EGFR-TKI耐药的影响。

方法

选择NSCLC细胞株H1975和H3255为研究对象，实时荧光定量PCR法检测两株细胞的突变状态、克隆形成实验观察两株细胞的放射敏感性，MTT法检测各处理组两株细胞对EGFR-TKI的抗药性。

结果

H1975为T790M+L858R双突变株、H3255是仅有L858R的单突变株；各处理组H1975及H3255的存活分数未见明显差异（P=0.952），提示T790M突变对NSCLC细胞株的放射敏感性无影响；2.5 Gy X线辐射组，H1975的IC₅₀为（0.678, 2±0.373）μmol/L，较0 Gy对照组的（3.520±0.821）μmol/L明显下降，差异有统计学意义（P=0.008），H1975相较于H3255的抗药性也从85.9倍下降为39.2倍。

结论

电离辐射可降低NSCLC细胞株T790M突变所致的TKI耐药，本实验的研究结果为后续的体内和临床研究提供了研究依据；EGFR-TKI治疗期间联合放射治疗对克服T790M突变介导的耐药性有望成为一种有希望的治疗策略。

[Study of the Changes on Tree Shrew Bronchial Epithelium Induced by Xuanwei Bituminous Coal Dust]

BACKGROUND AND OBJECTIVE

Lung cancer is the type of cancer with the highest incidence and mortality in numerous countries and regions. Establishing an appropriate animal model that can be used to simulate lung cancer etiology, pathogenesis, and similar processes, is urgent. We explore the feasibility of establishing a lung cancer model induced by Xuanwei bituminous coal dust PM10 (particulate matter with diameters of 10 μm or less), which affects bronchial epithelium of tree shrews.

METHODS

The neck skin of adult tree shrews is dissected, and the thyroid cartilage is fully exposed. Subsequently, the weak part at the top of the thyroid cartilage is treated with intratracheal agents by perfusion via a special infusion needle puncture method. Regular X-ray examination and lung tissue biopsy were performed on the sacrificed animals to observe changes in pulmonary imaging and bronchial epithelial cells after perfusion of Xuanwei bituminous coal dust PM 10.

RESULTS

The tree shrews of the experimental group (exposed to bituminous coal dust) died in a week after perfusion with PM10, whereas no animal died until the end of the experiment in the blank control and the solvent control groups. Sections of lung tissue biopsy of the regularly killed tree shrews were stained with hematoxylin and eosin. The lung tissues of tree shrews in the experimental group showed a serial changes caused by bronchial epithelial hyperplasia, such as squamous metaplasia, dysplasia, and early invasive carcinoma, whereas no significant pathological changes were observed in the blank control and solvent control groups.

CONCLUSIONS

Endotracheal infusion of Xuanwei bituminous coal dust PM10 induces lung cancer in tree shrews. Thus, the lung cancer model was established.
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[Regulation Mechanism of MTA3 in the Apoptosis of NSCLC Cells]

背景与目的

肿瘤转移基因(metastasis associated gene, MTA)是一个肿瘤候选基因家族, 主要包括MTA1、MTA2、MTA3, 已有的研究证实在不同肿瘤中MTA3发挥着相反的作用, 本研究旨在探讨MTA3在肺癌细胞中调控细胞凋亡方面的影响。

方法

应用Western blot方法和Real-time PCR方法检测肺癌细胞系A549和H157中MTA3的转染效率, 流式细胞仪方法检测上调/下调MTA3后肺癌细胞凋亡情况, Western blot方法检测下调MTA3后凋亡相关基因的表达。

结果

在肺癌细胞系A549和H157中干扰MTA3后则促进细胞凋亡, 同时引起凋亡相关蛋白Bax、Cleved-Caspase-3、p-PARP表达上调及Bcl-2表达下调。

结论

MTA3在肺癌细胞系A549和H157细胞中通过抑制凋亡相关基因的表达抑制细胞凋亡。

[Expression and Clinical Significance of MAGE-C2 in Lung Adenocarcinoma]

BACKGROUND

The aim of this study is to detect the expression of melanoma antigen-C2 (MAGE-C2) in lung adenocarcinoma tissues and adjacent non-cancerousous tissues and analyze its clinical significance.

METHODS

The expression level of MAGE-C2 mRNA and MAGE-C2 protein were measured in 87 cases of lung adenocarcinoma tissues and adjacent non-cancerous tissues were detected by Real-time fluorescence quantitative PCR and Western blot.

RESULTS

Over-expression of the MAGE-C2 mRNA and MAGE-C2 protein were observed in lung adenocarcinoma tissues (53/87, 60.9%), but nor in adjacent non-cancerous tissues. The expressions of MAGE-C2 mRNA and MAGE-C2 protein were closely associated with clinical stage, metastasis and differentiation (P<0.05). The expression rate of MAGE-C2 mRNA had no relationship with gender, age, smoking (P>0.05). The expression of MAGE-C2 had an adverse effect on overall survival rate (P<0.05).

CONCLUSIONS

Over-expression of the MAGE-C2 mRNA and protein is existed in lung adenocarcinoma. The high expression of MAGE-C2 may be closely related to the occurrence and development in lung adenocarcinoma. MAGE-C2 may predict a poor prognosis and could be as a novel lung adenocarcinoma molecule marker.
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[Effect of Long Non-coding RNA SPRY4-IT1 on Invasion and Migration of A549 Cells]

背景与目的

人长链非编码RNA基因的异常表达与多种肿瘤有关。本研究旨在探讨人长链非编码RNA基因SPRY4-ITl对肺癌细胞A549侵袭和迁移能力的影响及机制。

方法

将SPRY4-ITl转染入肺癌A549细胞系，采用RT-PCR方法检测重组质粒在细胞中表达水平比较；采用MTT和Transwell检测A549细胞侵袭和迁移能力的变化，采用Western blot方法检测SPRY4-ITl对MMP-2和MMP-9蛋白的影响。

结果

转染pcDNA3.1-SPRY4-ITl细胞划痕两侧细胞间距较转染pcDNA3.1细胞明显变窄，其穿膜细胞数为（207 ± 34）个/视野，相比对照组明显增多（P < 0.05），且转染pcDNA3.1-SPRY4-ITl细胞中的基质金属蛋白酶（matrix metalloproteinase, MMP）-2及MMP-9蛋白表达较转染空质粒组均有升高。

结论

在肺癌A549细胞中过表达SPRY4-IT1可增强细胞的侵袭、迁移能力，且细胞内MMP-2及MMP-9表达升高，提示SPRY4-IT1可能通过调控MMP影响肺癌的侵袭和转移能力。

[Influence of Berberine on Cisplatin Antineoplastic Effect in A549 Cells]

背景与目的

以顺铂为基础的化疗方案是晚期非小细胞肺癌的一线化疗方案，但是由于顺铂的不良反应严重及耐药性的产生均限制了它的临床应用，本研究采用联合用药的方式观察黄连素对顺铂抗肿瘤作用的影响，并探讨其可能机制。

方法

分别观察黄连素对肺腺癌细胞A549细胞中总Cx43蛋白、细胞膜Cx43蛋白的表达以及细胞缝隙连接功能的改变，通过标准细胞集落克隆实验观察黄连素对顺铂细胞毒性的影响；并观察PKC激酶的表达。

结果

黄连素在0 μM-10 μM浓度范围内对细胞无毒性，通过增加细胞内总Cx43蛋白和胞膜Cx43蛋白的表达而增强细胞缝隙连接功能；这种作用与PKC的活性被抑制相关，抑制PKC活性可以进一步增加顺铂对A549细胞的毒性作用。

结论

黄连素可通过增加A549细胞的缝隙连接功能而明显增强顺铂的细胞毒性。

ERK1/2: Function, signaling and implication in pain and pain-related anxio-depressive disorders

Despite the increasing knowledge regarding pain modulation, the understanding of the mechanisms behind a complex and pathologic chronic pain condition is still insufficient. These knowledge gaps might result in ineffective therapeutic approaches to relieve painful sensations. As a result, severe untreated chronic pain frequently triggers the onset of new disorders such as depression and/or anxiety, and therefore, both the diagnosis and treatment of patients suffering from chronic pain become seriously compromised, prompting a self-perpetuating cycle of symptomatology. The extracellular signal-regulated kinases 1 and 2 (ERK1/2) are molecules strongly implicated in the somatic component of pain at the spinal cord level and have been emerging as mediators of the emotional-affective component as well. Although these molecules might represent good biomarkers, their use as pharmacological targets is still open to discussion as paradoxical information has been obtained. Here we review the current scientific literature regarding ERK1/2 signaling in the modulation of pain, depression and anxiety, including the emotional-affective spheres of the pain experience.

Nanocurcumin protects cardiomyoblasts H9c2 from hypoxia-induced hypertrophy and apoptosis by improving oxidative balance

Hypoxia-induced cardiomyocyte hypertrophy is evident; however, the distinct molecular mechanism underlying the oxidative stress-mediated damages to cardiomyocytes remains unknown. Curcumin (diferuloylmethane) is known for anti-hypertrophic effects, but low bioavailability makes it unsuitable to exploit its pharmacological properties. We assessed the efficacy of nanotized curcumin, i.e. nanocurcumin, in ameliorating hypoxia-induced hypertrophy and apoptosis in H9c2 cardiomyoblasts and compared it to curcumin. H9c2 cardiomyoblasts were challenged with 0.5 % oxygen, for 24 h to assess hypoxia-induced oxidative damage, hypertrophy and consequent apoptosis. The molecular mechanism underlying the protective efficacy of nanocurcumin was evaluated in regulating Raf-1/Erk-1/2 apoptosis by caspase-3/-7 pathway and oxidative stress. Nanocurcumin ameliorated hypoxia-induced hypertrophy and apoptosis in H9c2 cells significantly (p ≤ 0.01), by downregulating atrial natriuretic factor expression, caspase-3/-7 activation, oxidative stress and stabilizing hypoxia-inducible factor-1α (HIF-1α) better than curcumin. Nanocurcumin provides insight into its use as a potential candidate in curing hypoxia-induced cardiac pathologies by restoring oxidative balance.

Sodium-glucose transporter-2 (SGLT2; SLC5A2) enhances cellular uptake of aminoglycosides

Aminoglycoside antibiotics, like gentamicin, continue to be clinically essential worldwide to treat life-threatening bacterial infections. Yet, the ototoxic and nephrotoxic side-effects of these drugs remain serious complications. A major site of gentamicin uptake and toxicity resides within kidney proximal tubules that also heavily express electrogenic sodium-glucose transporter-2 (SGLT2; SLC5A2) in vivo. We hypothesized that SGLT2 traffics gentamicin, and promotes cellular toxicity. We confirmed in vitro expression of SGLT2 in proximal tubule-derived KPT2 cells, and absence in distal tubule-derived KDT3 cells. D-glucose competitively decreased the uptake of 2-(N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)-2-deoxyglucose (2-NBDG), a fluorescent analog of glucose, and fluorescently-tagged gentamicin (GTTR) by KPT2 cells. Phlorizin, an SGLT2 antagonist, strongly inhibited uptake of 2-NBDG and GTTR by KPT2 cells in a dose- and time-dependent manner. GTTR uptake was elevated in KDT3 cells transfected with SGLT2 (compared to controls); and this enhanced uptake was attenuated by phlorizin. Knock-down of SGLT2 expression by siRNA reduced gentamicin-induced cytotoxicity. In vivo, SGLT2 was robustly expressed in kidney proximal tubule cells of heterozygous, but not null, mice. Phlorizin decreased GTTR uptake by kidney proximal tubule cells in Sglt2^+/− mice, but not in Sglt2^−/− mice. However, serum GTTR levels were elevated in Sglt2^−/− mice compared to Sglt2^+/− mice, and in phlorizin-treated Sglt2^+/− mice compared to vehicle-treated Sglt2^+/− mice. Loss of SGLT2 function by antagonism or by gene deletion did not affect gentamicin cochlear loading or auditory function. Phlorizin did not protect wild-type mice from kanamycin-induced ototoxicity. We conclude that SGLT2 can traffic gentamicin and contribute to gentamicin-induced cytotoxicity.

The effect of orexin-A on cardiac dysfunction mediated by NADPH oxidase-derived superoxide anion in ventrolateral medulla

Hypocretin/orexin-producing neurons, located in the perifornical region of the lateral hypothalamus area (LHA) and projecting to the brain sites of rostral ventrolateral medulla (RVLM), involve in the increase of sympathetic activity, thereby regulating cardiovascular function. The current study was designed to test the hypothesis that the central orexin-A (OXA) could be involved in the cardiovascular dysfunction of acute myocardial infarction (AMI) by releasing NAD(P)H oxidase-derived superoxide anion (O2 (-)) generation in RVLM, AMI rat model established by ligating the left anterior descending (LAD) coronary artery to induce manifestation of cardiac dysfunction, monitored by the indicators as heart rate (HR), heart rate variability (HRV), mean arterial pressure (MAP) and left intraventricular pressure. The results showed that the expressions of OXA in LHA and orexin 1 receptor (OX1R) increased in RVLM of AMI rats. The double immunofluorescent staining indicated that OX1R positive cells and NAD(P)H oxidative subunit gp91phox or p47phox-immunoreactive (IR) cells were co-localized in RVLM. Microinjection of OXA into the cerebral ventricle significantly increased O2 (-) production and mRNA expression of NAD(P)H oxidase subunits when compared with aCSF-treated ones. Exogenous OXA administration in RVLM produced pressor and tachycardiac effects. Furthermore, the antagonist of OX1R and OX2R (SB-408124 and TCS OX2 29, respectively) or apocynin (APO), an inhibitor of NAD(P)H oxidase, partly abolished those cardiovascular responses of OXA. HRV power spectral analysis showed that exogenous OXA led to decreased HF component of HRV and increased LF/HF ratio in comparison with aCSF, which suggested that OXA might be related to sympathovagal imbalance. As indicated by the results, OXA might participate in the central regulation of cardiovascular activities by disturbing the sympathovagal balance in AMI, which could be explained by the possibility that OXR and NAD(P)H-derived O2 (-) in RVLM mediates OXA-induced cardiovascular responses.

Orexin A regulates cardiovascular responses in stress-induced hypertensive rats

Several pieces of evidence indicate that the rostral ventrolateral medulla (RVLM) is probably one of the key neural structures mediating the pressor effects of orexins in the brain. Nitric oxide synthase/nitric oxide (NOS/NO) system in the RVLM modulates cardiovascular activities. Our experiments were designed to test the hypothesis that orexin-A (OXA) is involved in the mechanism of stress-induced hypertension (SIH) by adjusting NOS/NO system in the RVLM. The stress-induced hypertensive rats (SIHR) model was established by electric foot-shocks and noises. Here we examined the expression of OXA immunoreactive (OXA-IR) cells in the lateral hypothalamus (LH) and the protein level of orexin 1 receptor (OX1R) in the RVLM of SIHR, and we found that the expressions of OXA-IR and OX1R were higher than those of the control group. The double-staining immunohistochemical evidence showed that OX1R immunoreactive (OX1R-IR) cells and neuronal nitric oxide synthase (nNOS) or inducible nitric oxide synthase (iNOS) immunoreactive (IR) cells were co-localizated in the RVLM. Microinjection of OXA (10, 50, 100 pmol/100 nl) into the unilateral (right) RVLM of control rats or SIHR produced pressor and tachycardiac effects in a dose-dependent manner. SB-408124 (100 pmol/100 nl, an antagonist of OX1R) or TCS OX2 29 (100 pmol/100 nl, an antagonist of OX2R) partly abolished the cardiovascular effects of exogenously-administrated OXA into the RVLM of control rats and SIHR, and lowered the increased systolic blood pressure (SBP) and heart rate (HR) of SIHR, with no difference in statistical significance between the two antagonists' effects. Microinjection into the RVLM of both control and SIHR groups of 7-Ni (0.05 pmol/100 nl, nNOS inhibitor) or Methylene Blue [100 pmol/100 nl, an inhibitor of soluble guanylate cyclase (sGC)] suppressed the OXA-induced increase of SBP and HR, whereas microinjection of AG (1, 10, 100 pmol/100 nl) had no obvious effects on the OXA-induced increase of SBP and HR. Our results indicate that OXA in the RVLM may participate in the central regulation of cardiovascular activities in SIHR, and OX1R and OX2R both have important roles in it. The cardiovascular effects of OXA in the RVLM may be induced by nNOS-derived NO, which activated sGC-associated signaling pathway.