Promoter methylation of the RGC32 gene in nonsmall cell lung cancer

BACKGROUND:

Lung cancer is the leading cause of cancer‐related deaths worldwide. Epigenetic inactivation of certain genes by aberrant promoter methylation is recognized as a crucial component in the initiation and progression of lung cancer. Response gene to complement 32 (RGC32) has been identified as a cell cycle regulator induced by activation of complements; however, its role in carcinogenesis is still controversial.

METHODS:

The authors examined the methylation status in the promoter region of RGC32 gene in nonsmall cell lung cancers (NSCLCs) using a methylation‐specific PCR and correlated the results with clinicopathological features.

RESULTS:

RGC32 methylation was found in 45 of 173 NSCLCs (26.0%) and was related to the gene expression. RGC32 methylation was more frequent in females than in males (P<0.05). RGC32 methylation was not significantly associated with the prognosis of patients; however, when the patients were categorized by TP53 mutational status, the effect of RGC32 methylation on prognosis was significantly different between those with and without TP53 mutations (P = .005 [test for homogeneity]). Specifically, RGC32 methylation was associated with significantly worse survival in the cases with wild‐type TP53, whereas it exhibited a better survival outcome in the cases with TP53 mutations.

CONCLUSIONS:

The current findings suggest that methylation‐associated down‐regulation of RGC32 plays an important role in the pathogenesis of NSCLC, particularly in females. However, further studies with a large number of cases are needed to confirm the authors' findings. Cancer 2011. © 2010 American Cancer Society.     

A Na+/Ca2+ exchanger isoform, NCX1, is involved in retinal cell death after N-methyl-D-aspartate injection and ischemia-reperfusion

We investigated the expression of Na(+)/Ca(2+) exchanger (NCX) and the functional role of NCX in retinal damage by using NCX1-heterozygous deficient mice (NCX1(+/-)) and SEA0400 (2-[4-[(2,5-difluorophenyl)methoxy] phenoxy]-5-ethoxyaniline), a selective NCX inhibitor in vivo. We also examined the role of NCX in oxygen-glucose deprivation (OGD) stress with a retinal ganglion cell line (RGC-5) cell culture in vitro. The expression of NCX1 was confirmed and entirely localized in retina by immunoblotting and immunohistochemistry, respectively. NCX1(+/-) mice possessed significant protection against retinal damage induced by intravitreal injection of N-methyl-D-aspartate (NMDA). SEA0400 at 3 and 10 mg/kg significantly reduced NMDA- or high intraocular pressure-induced retinal cell damage in mice. Furthermore, SEA0400 reduced the number of TUNEL (terminal deoxynucleotidyl transferase dUTP nick-end labeling)-positive cells and the expression of phosphorylated mitogen-activated protein kinases (ERK1/2, JNK, p38) induced by NMDA injection. In RGC-5, SEA0400 at 0.3 and 1 microM significantly inhibited OGD-induced cell damage. OGD-induced cell damage was aggravated by ouabain (a Na(+),K(+)-ATPase inhibitor) at 100 microM, and this increased damage was significantly reduced by SEA0400 at 1 microM. In conclusion, these results suggest that NCX1 may play a role in retinal cell death induced by NMDA and ischemia-reperfusion.     

大鼠坐骨神经移植段对受损的视网膜节细胞影响的形态学研究

选用成年大鼠,切断视神经后,将自体周围神经段(2mm/每段)植入眼球玻璃体内,存活2周,取视网膜沿视轴纵切开,Nissl染色,光镜观察,并用计算机图像分析仪(IBAS 2000)测量面积。结果发现,植入周围神经段的各组视网膜节细胞未见溃变现象,测量的视网膜节细胞胞体平均面积比正常动物者明显增加,每组均可见一些超过正常视网膜节细胞面积的巨大细胞,胞体呈椭圆形,其长轴与节细胞排列方向一致;当增加周围神经移植段数量或缩短两个周围神经移植段植入点的距离时,视网膜节细胞的平均面积和巨大节细胞构成比即随之增大。仅切断视神经的对照组动物视网膜神经节则出现溃变。     

Taurine: The comeback of a neutraceutical in the prevention of retinal degenerations

Taurine is the most abundant amino acid in the retina. In the 1970s, it was thought to be involved in retinal diseases with photoreceptor degeneration, because cats on a taurine-free diet presented photoreceptor loss. However, with the exception of its introduction into baby milk and parenteral nutrition, taurine has not yet been incorporated into any commercial treatment with the aim of slowing photoreceptor degeneration. Our recent discovery that taurine depletion is involved in the retinal toxicity of the antiepileptic drug vigabatrin has returned taurine to the limelight in the field of neuroprotection. However, although the retinal toxicity of vigabatrin principally involves a deleterious effect on photoreceptors, retinal ganglion cells (RGCs) are also affected. These findings led us to investigate the possible role of taurine depletion in retinal diseases with RGC degeneration, such as glaucoma and diabetic retinopathy. The major antioxidant properties of taurine may influence disease processes. In addition, the efficacy of taurine is dependent on its uptake into retinal cells, microvascular endothelial cells and the retinal pigment epithelium. Disturbances of retinal vascular perfusion in these retinal diseases may therefore affect the retinal uptake of taurine, resulting in local depletion. The low plasma taurine concentrations observed in diabetic patients may further enhance such local decreases in taurine concentration. We here review the evidence for a role of taurine in retinal ganglion cell survival and studies suggesting that this compound may be involved in the pathophysiology of glaucoma or diabetic retinopathy. Along with other antioxidant molecules, taurine should therefore be seriously reconsidered as a potential treatment for such retinal diseases.     

Electrical stimulation of cerebellar fastigial nucleus promotes the expression of growth arrest and DNA damage inducible gene β and motor function recovery in cerebral ischemia/reperfusion rats

This study focused on the effects of electrical stimulation of cerebellar fastigial nucleus on the expression of growth arrest and DNA damage inducible gene β (Gadd45β) and on motor function recovery after focal cerebral ischemia/reperfusion (I/R) in rats. Sprague-Dawley (SD) rats were randomly divided into 4 groups: sham I/R (control group), I/R (I/R group), I/R with sham stimulation and I/R with electrical stimulation at 6h, 12h, 24h, 2d and 3d after I/R. Cerebral ischemia and reperfusion was established by nylon monofilament occlusion method. Fastigial nucleus (FN) electrical stimulation was applied at 2h after ischemia for 1h. The changes in the expression of Gadd45β were analyzed by immunohistochemistry, real-time polymerase chain reaction (PCR) and Western-blot respectively. Another group of rats were divided into the same 4 groups. Montoya staircase test score was used to test the motor function of affected forelimb. The levels of Gadd45β were significantly elevated after I/R injury. FN electrical stimulation treatment elevated the expression of Gadd45β further and improved motor function recovery. These results suggest that FN electrical stimulation can promote the expression of Gadd45β and motor function recovery after focal cerebral ischemia.     

Heat shock proteins in the retina: Focus on HSP70 and alpha crystallins in ganglion cell survival

Heat shock proteins (HSPs) belong to a superfamily of stress proteins that are critical constituents of a complex defense mechanism that enhances cell survival under adverse environmental conditions. Cell protective roles of HSPs are related to their chaperone functions, antiapoptotic and antinecrotic effects. HSPs' anti-apoptotic and cytoprotective characteristics, their ability to protect cells from a variety of stressful stimuli, and the possibility of their pharmacological induction in cells under pathological stress make these proteins an attractive therapeutic target for various neurodegenerative diseases; these include Alzheimer's, Parkinson's, Huntington's, prion disease, and others. This review discusses the possible roles of HSPs, particularly HSP70 and small HSPs (alpha A and alpha B crystallins) in enhancing the survival of retinal ganglion cells (RGCs) in optic neuropathies such as glaucoma, which is characterized by progressive loss of vision caused by degeneration of RGCs and their axons in the optic nerve. Studies in animal models of RGC degeneration induced by ocular hypertension, optic nerve crush and axotomy show that upregulation of HSP70 expression by hyperthermia, zinc, geranyl–geranyl acetone, 17-AAG (a HSP90 inhibitor), or through transfection of retinal cells with AAV2-HSP70 effectively supports the survival of injured RGCs. RGCs survival was also stimulated by overexpression of alpha A and alpha B crystallins. These findings provide support for translating the HSP70- and alpha crystallin-based cell survival strategy into therapy to protect and rescue injured RGCs from degeneration associated with glaucomatous and other optic neuropathies.     

脑神经生长素对急性高眼压视网膜神经节细胞损伤的保护作用

目的：观察脑神经生长素对兔眼急性高眼压视网膜神经节细胞损伤的保护作用。方法：健康成年新西兰大耳白兔３０只,随机分为５组,每组６只,均一眼为高眼压模型眼,另一眼为自身对照眼,每组３只兔术后每日肌肉注射ＣＮＧ０．２ｍｌ,５组兔分别于制造模型眼后１、３、７、１５和３０天处死,应用免疫组织化学ＳＡＢＣ法检测ｂｃｌ－２和ＴＧＦ－／β１,定量分析ＣＮＧ的药物疗效。结果：ＣＮＧ应用３天后,ｂｃｌ－２基因蛋白过表