SP2509, a Selective Inhibitor of LSD1, Suppresses Retinoblastoma Growth by Downregulating β-catenin Signaling

PurposeTo study the role of lysine-specific demethylase 1 (LSD1) in retinoblastoma (RB) growth and to determine whether the LSD1 inhibitor SP2509 can inhibit RB progression.MethodsWe detected the levels of LSD1 in 12 RB tissue samples, two RB cell lines (Y79 and Weri-RB1), and a retinal pigment epithelium cell line (ARPE-19). Overexpression or knockdown of LSD1 was performed to examine the role of LSD1 in RB cancer cell survival. In vitro and in vivo experiments were conducted to detect the antitumor effect of SP2509, and the antitumor mechanism of SP2509 was examined by RNA sequencing and Western blot.ResultsLSD1 is overexpressed in RB tissues and cells and increases RB cancer cell viability and colony formation ability. The LSD1 inhibitor SP2509 inhibits RB cell proliferation in vitro and in vivo. Treatment with SP2509 increases the levels of dimethylated histone 3 lysine 4 (H3K4me2) and inhibits the expression of β-catenin signaling pathway–related proteins in RB cells.ConclusionsWe demonstrated that LSD1 is overexpressed in RB cells and promotes RB cell survival. The LSD1 inhibitor SP2509 exerted strong growth inhibition in vitro and in vivo, which was at least partially mediated by suppression of the β-catenin pathway.     

Ubiquitination-Related miRNA–mRNA Interaction Is a Potential Mechanism in the Progression of Retinoblastoma

PurposeRetinoblastoma (RB) is the most common primary malignant intraocular cancer. The etiology of RB is complex, and the mechanisms driving its progression remain unclear. Here, we used a series of bioinformatics approaches and experimental methods to investigate the potential regulatory mechanism involved in RB progression.MethodsThe common differentially expressed genes were obtained from the public dataset {"type":"entrez-geo","attrs":{"text":"GSE97508","term_id":"97508"}}GSE97508. Protein–protein interaction (PPI) network, correlation, and functional enrichment analyses were carried out. The candidate genes were verified in different RB cell lines, and ARPE19 cells served as control. miRNA–mRNA interaction analysis was performed and confirmed by real-time PCR. The CCK-8 assay was conducted to detect cell viability, and the transwell assay was utilized for evaluating the abilities of cell migration and invasion.ResultsOverall, a total of 258 common differentially expressed genes associated with RB progression were screened out. The PPI network analysis further identified eight downregulated genes mainly enriched in the protein ubiquitination pathway. Moreover, we confirmed UBE2E1, SKP1, FBXO9, FBXO15, and RNF14 from among eight genes through experimental validation in vitro. Furthermore, miRNA–mRNA interaction and real-time PCR analysis of five hub genes revealed that ubiquitination-related miR-548k was involved in RB progression. Loss- and gain-of-function experiments demonstrated that miR-548k and its targets were essential for cell viability, migration, and invasion in the RB cells.ConclusionsOur data indicate that the dysregulation of protein ubiquitination may play an important role in RB progression, and ubiquitination-related miR-548k may be a promising therapeutic target for RB.     

视网膜母细胞瘤中Fas/Fas配体表达及 与凋亡的关系

目的观察视网膜母细胞瘤(retinoblastoma, RB)　Fas/Fas 配 体 (Fas ligand ,FasL)表达及与凋亡的相关性。方法应用免疫组织化学染色法观察32例RB标本中 Fas/FasL的表达及分布,并对32例用光镜、其中4例用电镜及12例用末端脱氧核苷酸转移酶介导的生物素化脱氧尿苷三磷酸末端标记 (t erminal deoxynucleotidyl transferase mediated biotin dUTP nick end labeling, T UNEL)染色观察细胞凋亡,分析与Fas/FasL表达的关系。结果光镜下凋亡细胞主要位于RB退化区,电镜下可见染色质边集和凋亡小体等凋亡特征 ;TUNEL显示阳性标识主要位于RB退化区及死亡区。Fas及 FasL在所有RB中均呈阳性表达 。Fas和 FasL表达与凋亡指数 (apoptosis index, AI)呈正相关 (P<0．01 ,P<0．001)。结论凋亡在RB中普遍存在,可能是触发RB细胞死亡的 主要方式;Fas系统在RB的发生发展中起重要作用。Fas系统上调可能会诱导RB细胞凋亡。(中华眼底病杂志,2001,17:21-23)     

Expression levels of autophagy related proteins and their prognostic significance in retinocytoma and retinoblastoma

AIM:To discuss the prognostic significant of autophagy related proteins (ARPs) in retinoblastoma (RB) and to find the molecular marker to distinguish retinocytoma (RC) and RB byinvestigating the different expression profiling of microtubule-associated protein light chain 3 (LC3B) and other ARPs in RC and RB.METHODS: Specimens with retinocytoma region (RCR) or mainly composed with Flexner-Winterstein rosettes (FWR) were screen out from 219 paraffin-embedded RB samples and respectively taken as RCR group and FWR group. Others were taken as undifferentiated (UD) group. Immunochemistry (IHC) of LC3B and electronic microscopy was used to identify autophagy. The IHC scores of LC3B and other ARPs, such as Beclin, PTEN, p27, p16^INK4a, mTOR and BCL-2 were compared and correlation analysis was applied to find potential proteins which may involve in autophagy regulation. The prognostics significance of LC3B was evaluated by comparing the high risk features (HRFs) in 3 groups of total 219 samples.RESULTS: Twenty-one specimens with RCR and 36 specimens mainly composed with FWR were screen out. RCR cell had a high level of LC3B and lots of autophagic vacuoles. Beclin, PTEN, p27 had positive correlation with LC3, and p16^INK4a had negative correlation, while the expression of mTOR and BCL-2 in RCR and RB region did not show any difference. Cases with RCR had lower rate of HRFs than undifferentiated cases.CONCLUSION: ARPs had different expression pattern between RCR and other pathological types of RB, and could be ideal markers to distinguish RC from RB. Our finding indicated cases with RCR had favorable prognosis just like those with FWR.     

High Glucose Aggravates Retinal Endothelial Cell Dysfunction by Activating the RhoA/ROCK1/pMLC/Connexin43 Signaling Pathway

PurposeThis research aims to explore the mechanism underlying the relationship between RhoA/ROCK signaling and Connexin43 (Cx43) in retinal endothelial cell dysfunction and to evaluate the protective effect of ROCK inhibitors against retinal endothelial cell dysfunction in diabetic retinopathy (DR) models.MethodsTUNEL staining, hematoxylin and eosin staining, a retinal digestion assay, and Evans blue assay were conducted to explore the effect of fasudil in alleviating retinal dysfunction induced by DR. ELISA, the CCK-8 assay, and flow cytometry were conducted to study inflammation, viability, and apoptosis of mouse retinal microvascular endothelial cells treated with high glucose and ROCK inhibitors. The qRT–PCR and Western blotting were used to evaluate the expression of RhoA, ROCK1, ROCK2, MLC, pMLC, and Cx43. Co-immunoprecipitation was used to verify the interaction between pMLC and Cx43. Immunofluorescence and scrape-loading and dye transfer were used to evaluate the expression and function of Cx43.ResultsMarked endothelial cell dysfunction resulting from the activation of RhoA/ROCK1 signaling was found in in vivo and in vitro models of DR. Via interaction with pMLC, which is downstream of RhoA/ROCK1, a significant downregulation of Cx43 was observed in retinal endothelial cells. Treatment with ROCK inhibitors ameliorated retinal endothelial dysfunction in vitro. The ROCK inhibitor, fasudil, significantly alleviated retinal dysfunction as shown by a decrease of retinal acellular capillaries, an improvement of vascular permeability, and a reduction of cell apoptosis in vivo.ConclusionsOur study highlights a novel mechanism that high glucose could activate RhoA/ROCK1/pMLC signaling, which targets the expression and localization of Cx43 and is responsible for cell viability, apoptosis, and inflammation, resulting in retinal endothelial cell injury. ROCK inhibitors markedly ameliorate endothelial cell dysfunction, suggesting their therapeutic potential for diabetic retinopathy.     

p21^WAF1/CIP1在视网膜母细胞瘤中的表达及意义

目的探讨p21^WAF1/CIP1在视网膜母细胞瘤（RB）中的表达及其与肿瘤的病理分期、组织分型、浸润深度的关系。方法利用免疫组织化学法检测p21^WAF1/CIP1在46例RB组织和15例正常视网膜组织中的表达。结果p21^WAF1/CIP1主要表达于细胞核及细胞浆内,在RB中的阳性表达率为47.83%,与正常视网膜组织相比差异有统计学意义（P=0.007）,并随肿瘤病理分期的进展而下降,与组织分型和浸润深度有关（P〈0.05）。结论p21^WAF1/CIP1在RB的发生发展过程中起重要作用,表达的下降与肿瘤恶化及预后不良相关。     

miR-218通过下调Bmi-1表达抑制人视网膜母细胞瘤细胞生长

目的：探讨miR-218在人视网膜母细胞瘤中的表达、临床意义及其分子机制。

方法：实时定量PCR检测miR-218在视网膜母细胞瘤及瘤旁组织中的表达,并分析其与临床病理特征的关系。检测miR-218在视网膜母细胞瘤细胞系中的表达,并用miR-218模拟物转染Y79细胞,MTT及流式细胞仪检测Y79细胞的增殖、凋亡情况,RT-PCR和Western-blot法检测Bmi-1 mRNA及蛋白的表达。

结果：miR-218在视网膜母细胞瘤组织中的表达水平显著低于对应瘤旁组织; miR-218低表达与神经浸润、分化程度密切相关; miR-218可显著抑制Y79细胞的增殖并促进其凋亡,并下调Bmi-1的mRNA及蛋白表达水平。

结论：miR-218在人视网膜母细胞瘤组织中表达下调,并与临床病理相关,miR-218抑制Y79细胞增殖、促进凋亡的作用可能与下调Bmi-1有关。     

Xanthatin Selectively Targets Retinoblastoma by Inhibiting the PLK1-Mediated Cell Cycle

PurposeRetinoblastoma is the most common primary intraocular malignant tumor in children. Although intra-arterial chemotherapy and conventional chemotherapy have become promising therapeutic approaches for advanced intraocular retinoblastoma, the side effects threaten health and are unavoidable, making the development of targeted therapy an urgent need. Therefore, we intended to find a potential drug for human retinoblastoma by screening an in-house compound library that included 89 purified and well-characterized natural products.MethodsWe screened a panel of 89 natural products in retinoblastoma cell lines to find the inhibitor. The inhibition of the identified inhibitor xanthatin on cell growth was detected through half-maximal inhibitory concentration (IC₅₀), flow cytometry assay, and zebrafish model system. RNA-seq further selected the target gene PLK1.ResultsWe reported the discovery of xanthatin as an effective inhibitor of retinoblastoma. Mechanistically, xanthatin selectively inhibited the proliferation of retinoblastoma cells by inducing cell cycle arrest and promoting apoptosis. Interestingly, xanthatin targeted PLK1-mediated cell cycle progression. The efficacy of xanthatin was further confirmed in zebrafish models.ConclusionsCollectively, our data suggested that xanthatin significantly inhibited tumor growth in vitro and in vivo, and xanthatin could be a potential drug treatment for retinoblastoma.     

EGF Receptor Signaling Modulates YAP Activation and Promotes Experimental Proliferative Vitreoretinopathy

PurposeBoth epidermal growth factor receptor (EGFR) and the Yes-associated protein (YAP) signaling pathway are implicated in cell proliferation and differentiation. In this study, we explored whether the formation of proliferative vitreoretinopathy (PVR) depends on the interaction of the EGFR receptor and YAP pathway.MethodsWe studied the effects of EGFR and YAP activation on retinal fibrosis in a PVR mouse model as well as in knockout mice (conditional deletion of EGFR or YAP specifically in RPE cells). Reversal and knockdown experiments were performed to induce a model of ARPE-19 cells treated with TGF-β2 in vitro. The effect of EGFR/YAP signaling blockade on the PVR-induced cell cycle and TGF-β2–induced ARPE-19 cell activation was determined.ResultsThe EGFR inhibitor erlotinib or conditional deletion of EGFR attenuated YAP activation and decreased the expression of YAP and its downstream target Cyr61 and of connective tissue growth factor in vivo and in vitro. EGFR-PI3K-PDK1 signaling induced by PVR promoted YAP activation and cell cycle progression. Furthermore, activated EGFR signaling bypassed RhoA to increase the protein levels of YAP, C-Myc, CyclinD1, and Bcl-xl.ConclusionsOur work highlights that EGFR-PI3K-PDK1–dependent YAP activation plays a crucial role in the formation of PVR. Targeting EGFR and the YAP pathway provides promising therapeutic treatments for PVR.     

人眼视网膜母细胞瘤细胞凋亡的研究

目的 观察人视网膜母细胞（ｒｅｔｉｎｏｂｌａｓｔｏｍａ,ＲＢ）标本中细胞凋亡,探讨细胞凋亡在ＲＢ发生发展及消退中的作用。方法 用ＴＵＮＥＬ方法光镜和电镜观察人ＲＢ摘除眼球标本中是否存在细胞凋亡。结果 １５例人ＲＢ分化型和未分化型标本中有９例发现少量凋亡细胞,自发退化型ＲＢ中未发现凋亡细胞。每例中均见成片出现的坏死细胞。结论 视网膜母细胞瘤细胞死亡通过坏死与凋亡２种途径。细胞凋亡是ＲＢ自发退化的机制     

The E3 Ligase RNF157 Inhibits Lens Epithelial Cell Apoptosis by Negatively Regulating p53 in Age-Related Cataracts

PurposeAge-related cataract (ARC) is a major cause of vision impairment worldwide. The E3 ubiquitin ligase RING finger protein 157 (RNF157) is involved in regulating cell survival and downregulated in human cataractous lens samples. However, the function of RNF157 in cataracts remains unclear. This study aimed to determine the role of RNF157 in ARC.MethodsReal-time polymerase chain reaction (PCR) and Western blotting were used to analyze the expression of RNF157 in clinical lens capsules, rat cataract models, and oxidative stress cell models. Western blot analysis and flow cytometry were used to evaluate cell apoptosis. Co-IP assay, protein stability assay, and ubiquitination assay were used to detect the interaction between RNF157 and its substrate p53.ResultsThe expression of RNF157 was downregulated in human cataract samples, UVB-induced rat cataract model, and H₂O₂-treated human lens epithelial cells (LECs). Ectopic expression of RNF157 protected LECs from H₂O₂-induced apoptosis. In contrast, knockdown of RNF157 enhanced oxidative stress-induced apoptotic cell death. Moreover, silence of RNF157 in the rat ex vivo lens model exacerbated lens opacity. Mechanistically, RNF157 causes ubiquitination and degradation of the tumor antigen p53. Overexpression of p53 eliminated the antiapoptotic effects of RNF157, whereas p53 knockdown rescued RNF157 silencing-induced cell death.ConclusionsOur findings revealed that reduced RNF157 expression promoted LEC apoptosis by upregulating p53 in cataracts, suggesting that the regulation of RNF157 expression may serve as a potential therapeutic strategy for cataracts.