RNAi沉默RON基因对人结肠癌HT-29细胞侵袭和耐药性的抑制作用

目的:探讨RNAi沉默酪氨酸激酶受体RON(recepteur d'origine nantais)基因对人结肠癌HT-29细胞侵袭和对抗肿瘤药物敏感性的影响.方法:构建RON基因的RNAi慢病毒载体Lv-RON-siRNA.Real-time PCR和Western blotting检测RON基因的沉默效率及RON蛋白表达水平;Transwell侵袭实验和ATP-TCA(ATP-tumor chemosensitivity assay)检测RON基因对HT-29细胞侵袭和对药物敏感性的影响.结果:慢病毒载体Lv-RON-siRNA感染HT-29细胞对RON基因的沉默效果达到70％.Lv-RON-siRNA感染后,HT-29细胞侵袭力较对照组明显降低(0.97±0.072 vs 1.29±0.076,P＜0.05).Lv-RON-siRNA感染后,HT-29细胞对5-氟尿嘧啶(5-fluorouraci,5-FU)的IC90值和IC50值分别为(14.28 ±1.34)、(8.93±1.20) μg/ml,顺铂(cisplatin,DDP)的IC90值和IC50值分别为(1.91±0.22)、(0.64±0.07) μg/ml,均明显低于对照组(P＜0.01).结论:沉默RON基因表达能抑制HT-29细胞的侵袭力,提高细胞对5-FU和DDP的敏感性.     

RON (recepteur d’origine nantais) expression and its association with tumor progression in laryngeal squamous cell carcinoma

ObjectivesSeveral human tumor tissues show an aberrant expression and activation of recepteur d’origine nantais (RON). In this paper, we investigate the expression of RON in human laryngeal squamous cell carcinoma (SCC) and evaluate whether RON affects the tumor cell progression in human laryngeal SCC cell line.MethodsImmunohistochemistry was used to assess RON expression in human laryngeal SCC. To evaluate the impact of RON knockdown, the cell invasion assay and cell migration assay using small-interfering RNA were performed.ResultsThe expression of RON protein was dominantly observed in laryngeal SCC tissues relative to adjacent normal mucosa in all cases. Knockdown of RON resulted in significantly reduced cell invasion in human laryngeal SCC cells. Cell migration showed a marked decrease in RON knockdown laryngeal SCC cells compared to the negative control laryngeal SCC cells. Laryngeal SCC cell migration was enhanced by incubation with macrophage stimulating protein (MSP).ConclusionRON is highly expressed in human laryngeal SCC. We suggest that RON plays an important role in invasion, and metastasis of laryngeal SCC.     

反义核酸抑制RON基因表达对A549的体外作用

目的探讨针对人RON基因跨膜区段(RONm)反义核酸对肺癌细胞系A549活性和细胞增殖的抑制作用,研究以RONm为靶的肺癌基因治疗的可能性?方法将人RONm cDNA反向插入到真核表达载体pcDNA3.1中,转染肺癌细胞A549,利用ELISA检测细胞模型RON基因表达水平,同时利用MTT和细胞计数方法监测细胞生物学活性的变化.结果转染后的肺癌细胞RON基因表达量和细胞活性明显降低,并出现明显的细胞凋亡?结论RONm反义核酸明显抑制RON基因的表达,同时对肺癌细胞的生长有抑制作用,促进细胞凋亡?     

Immunohistochemical Analysis of Distribution of RON Receptor Tyrosine Kinase in Human Digestive Organs

The immunohistochemical distribution of RON receptor tyrosine kinase in digestive organs of both human fetus and adult, including the esophagus, stomach, duodenum, small intestine, colon, rectum, liver, gallbladder, pancreas, and spleen, was investigated semiquantitively using an affinity-purified rabbit polyclonal antibody. RON was observed to be widely distributed throughout various digestive organs and cell types in humans. The immunoreactivity for RON was observed in the epithelium of the esophagus, small intestine, colon, hepatocytes, Kupffer cells, and splenic macrophages both in the adult and the fetus, suggesting that the MSP/RON signaling pathway possesses the proper biological properties to possibly be involved in morphogenesis or differentiation of cells in these organs and cell types. Several organs differed in immunoreactivity between adult and fetus. No immunoreactive cells were found in the pancreas of adults; however, immunoreactivity was observed in acinar cells and in some of the duct or ductular cells and endocrine cells of the islet of the fetus. Similarly, immunoreactivity was not observed in gastric mucosa except in the intestinal metaplastic cells in adults; however, immunoreactivity was found in the foveolar epithelium of the stomach of the fetus. Although the biological significance of RON in malignancy is unclear, the presence of RON immunoreactivity in the fetus and it lack in the adult may indicate that RON is a oncofetal substance in human pancreas and stomach.     

The influence on cognitive processing from the switches of shooting angles in videos of real-world events: An ERP study

This work mainly focuses on the influence from switches of shooting angles in videos during the cognitive processing in the human brain. In the experiment we used the videos with switches of shooting angles as materials and compared the ERPs elicited by the switch frames and the non-switch frames in the videos, it was found that when subjects were asked to pay attention to the video contents, the switch frames would trigger P3a-RON waveforms, but no N400 waveform was found in the ERP results. This showed that when subjects were concerned with the video contents, the switches of shooting angles would distract their attention from the video contents, but as long as the semantic meaning of the videos were coherent, the switches of shooting angles would not lead to significant difficulties in semantic comprehension. At the same time, the experimental results also further proved that the P3a and RON generally reflect the processing of task-irrelevant visual stimuli.     

Distraction of task-relevant information processing by irrelevant changes in auditory, visual, and bimodal stimulus features: A behavioral and event-related potential study

Distractibility with auditory, visual, and bimodal stimulus changes was investigated using an audio-visual distraction paradigm. Participants were asked to discriminate between equiprobable short and long audio-visual stimuli. Infrequently, the auditory, the visual, or both parts of the stimuli changed. These rare deviations (deviants) were irrelevant for the actual task. The influence of the three types of deviant stimuli on the processing of task-relevant information was assessed with behavioral and event-related potential (ERP) measures assuming that bimodal deviants would lead to an increase in distraction. Behavioral and ERP results did not support this assumption, as reaction time (RT) prolongation and components amplitudes did not differ significantly for auditory and bimodal deviants. It is suggested that a maximal threshold of distraction accounts for these results. In addition, the processing of bimodal deviations was assessed. Audio-visual interactions were found following modality-specific deviance detection suggesting that integration only occurs with involuntary attention switching to task-irrelevant changes.     

Electrical responses reveal the temporal dynamics of brain events during involuntary attention switching

Surviving in the natural environment requires the rapid switching of attention among potentially relevant stimuli. We studied electrophysiologically the involuntary switching time in humans performing a task designed to study brain mechanisms of involuntary attention and distraction (C. Escera et al., 1998, J. Cogn. Neurosci., 10, 590-604). Ten subjects were instructed to discriminate visual stimuli preceded by a task-irrelevant sound, this being either a repetitive tone (P = 0.8) or a distracting sound, i.e. a slightly higher deviant tone (P = 0.1) or an environmental novel sound (P = 0.1). In different conditions, the sounds preceded the visual stimuli by 245 or 355 ms. Deviant tones and novel sounds prolonged reaction times significantly to subsequent visual stimuli by 7.4 (P < 0.02) and 15.2 ms (P < 0.003), respectively. In addition to a mismatch negativity (MMN) and a positive-polarity, 320-ms latency, P3a event-related potential associated, respectively, with detection of the distracting sound and the subsequent orienting of attention to it, a late frontal negative deflection was observed in distracting trials. The peak latency of this brain response from sound onset was 580 ms in the 245-ms condition and 115 ms longer in the 355-ms condition (P < 0.001), peaking consequently at 340 ms from visual stimulus onset, irrespective of the onset of the distracting sound. We suggest that this late frontal negative response may signal over the scalp the process of reallocating attention back to the original task after momentary distraction, and therefore that recovering from distraction may take a similar shifting time as orienting attention involuntarily towards unexpected novelty.     

Involuntary attention impairment in early Parkinson's disease: an event-related potential study

Dopaminergic nigro-striatal depletion interferes with the detection of novel stimuli. This suggests that Parkinson's disease (PD) may generate from the initial stages a failure in involuntary attention (IA), which can be studied through the distraction potential, composed by the mismatch negativity (MMN), the P3a and the reorientation negativity (RON). This study analyzed IA using event-related potentials (ERPs) in patients with early PD with and without dopaminergic replacement therapy. Twenty-five medicated, and 17 non-medicated patients with early PD were studied, as well as 20 healthy control subjects. All subjects performed an auditory distraction task while a digital EEG was being recorded. The distraction potential was obtained by averaging methodology. Each wave was analyzed with a Repeated Measures ANOVA test. The MMN was obtained in all subjects and no significant differences in mean amplitude were found among the groups. There was a main effect of group for the amplitude of P3a (F(2,59) = 4.8, p = 0.01, ? = 0.411), with a significant lower amplitude in the medicated group compared to the control group (MD = −1.03, p = 0.003). RON also showed a main effect of group (F(2,59) = 4.8, p = 0.01, ? = 0.467), with significantly lower amplitudes in non-medicated patients with respect to both the control and medicated groups (MD = 1.19, p = 0.01, MD = 1.27, p = 0.005, respectively). There were no significant differences in the latencies of any of the waves among the groups. The main finding of this study was the reduction in the IA in early PD. Reorientation of attention (RON) showed a dopaminergic modulation in these patients. These results represent the basis for future in depth studies on the involvement of IA in executive impairments in PD.     

A retrospective cohort study of radial optic neurotomy for severe central retinal vein occlusions

BACKGROUND: Radial optic neurotomy (RON) is a new surgical procedure that has, until now, been studied only in a case series format. This study was designed to evaluate the efficacy of RON in improving visual acuity in patients suffering from central retinal vein occlusion (CRVO) with visual acuity equal to or worse than 20/100. METHODS: A retrospective cohort study was conducted of consecutive CRVO patients, consisting of 19 who underwent RON and 38 observation subjects matched on presenting visual acuity. RESULTS: The observation group worsened by 0.25 logMAR units from baseline, whereas the surgery group improved by 0.29 logMAR. Multivariate linear regression modelling found that, having controlled for other significant predictors and confounders, the change in visual acuity in the surgery patients was 0.63 logMAR units better than in the observation patients. INTERPRETATION: Our data suggest that RON is a promising treatment for visual acuity loss in severe CRVO causing visual acuity equal to or worse than 20/100. These results should be interpreted cautiously because of the limitations of the study, including the retrospective study design and the use of Snellen visual acuity. Our data suggest that further evaluation of RON is warranted.