Long Noncoding RNA MRUL Promotes ABCB1 Expression in Multidrug-Resistant Gastric Cancer Cell Sublines

Multidrug resistance (MDR) is the most common cause of chemotherapy failure in gastric cancer (GC) treatment; however, the underlying molecular mechanisms remain elusive. Long noncoding RNAs (lncRNAs) can be involved in carcinogenesis, but the effects of lncRNAs on MDR are poorly understood. We show here that the lncRNA MRUL (MDR-related and upregulated lncRNA), located 400 kb downstream of ABCB1 (ATP-binding cassette, subfamily B, member 1), was significantly upregulated in two multidrug-resistant GC cell sublines, SGC7901/ADR and SGC7901/VCR. Furthermore, the relative expression levels of MRUL in GC tissues were negatively correlated with in vitro growth inhibition rates of GC specimens treated with chemotherapeutic drugs and indicated a poor prognosis for GC patients. MRUL knockdown in SGC7901/ADR and SGC7901/VCR cells led to increased rates of apoptosis, increased accumulation, and reduced doxorubicin (Adriamycin [ADR]) release in the presence of ADR or vincristine. Moreover, MRUL depletion reduced ABCB1 mRNA levels in a dose- and time-dependent manner. Heterologous luciferase reporter assays demonstrated that MRUL might positively affect ABCB1 expression in an orientation- and position-independent manner. Our findings indicate that MRUL promotes ABCB1 expression and is a potential target to reverse the MDR phenotype of GC MDR cell sublines.     

长链非编码RNA UCA1在胃癌多药耐药中的作用研究

目的:研究胃癌耐药细胞及其亲本细胞中长链非编码RNA UCA1的表达差异,探讨UCA1在胃癌多药耐药中的作用。方法:通过实时荧光定量PCR(q RT-PCR)检测胃癌耐药细胞SGC7901/ADR、SGC7901/VCR及其亲本细胞SGC7901中UCA1的表达差异;通过si RNA转染降低SGC7901/ADR中UCA1表达,MTT法检测细胞半数抑制浓度(IC50)的变化,流式细胞仪检测细胞凋亡变化。结果:QRT-PCR结果显示,UCA1在SGC7901/ADR和SGC7901/VCR胃癌耐药细胞表达显著高于SGC7901胃癌亲本细胞;MTT实验表明,干扰UCA1的SGC7901/ADR相对于阴性对照(NC)组的IC50显著降低;凋亡检测结果显示,在相同剂量化疗药物作用下,干扰UCA1后SGC7901/ADR凋亡率显著高于NC组;Western blot证实,干扰UCA1表达可显著降低BCL-2蛋白表达。结论:长链非编码RNA UCA1在胃癌耐药细胞表达显著升高,干扰UCA1表达可明显逆转胃癌耐药,UCA1可作为治疗胃癌耐药的重要分子靶标。     

Identification of two molecular subtypes of dysregulated immune lncRNAs in ovarian cancer

Long non-coding RNA (lncRNA) has increasingly been identified as a key regulator in pathologies such as cancer. Multiple platforms were used for comprehensive analysis of ovarian cancer to identify molecular subgroups. However, lncRNA and its role in mapping the ovarian cancer subpopulation are still largely unknown. RNA-sequencing and clinical characteristics of ovarian cancer were acquired from The Cancer Genome Atlas database (TCGA). A total of 52 lncRNAs were identified as aberrant immune lncRNAs specific to ovarian cancer. We redefined two different molecular subtypes, C1(188) and C2(184 samples), in “iClusterPlus” R package, among which C2 grouped ovarian cancer samples have higher survival probability and longer median survival time (P <0.05) with activated IFN-gamma response, Wound Healing and Cytotoxic lymphocytes signal; 456 differentially expressed genes were acquired in C1 and C2 subtypes using limma (3.40.6) package, among which 419 were up-regulated and 37 were down-regulated, in TCGA dataset. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) functional enrichment analysis revealed that these genes were actively involved in ECM-receptor interaction, PI3K-Akt signaling pathway interaction KEGG pathway. Compared with the existing immune subtype, the Cluster2 sample showed a substantial increase in the proportion of the existing C2 immune subtype, accounting for 81.37%, which was associated with good prognosis. Our C1 subtype contains only 56.49% of the existing immune C1 and C4, which also explains the poor prognosis of C1. Furthermore, 52 immune-related lncRNAs were used to divide the TCGA-endometrial cancer and cervical cancer samples into two categories, and C2 had a good prognosis. The differentially expressed genes were highly correlated with immune-cell-related pathways. Based on lncRNA, two molecular subtypes of ovarian cancer were identified and had significant prognostic differences and immunological characteristics.     

Effect of emodin on long non-coding RNA-mRNA networks in rats with severe acute pancreatitis-induced acute lung injury

Long non-coding RNAs (lncRNAs) contribute to disease pathogenesis and drug treatment effects. Both emodin and dexamethasone (DEX) have been used for treating severe acute pancreatitis-associated acute lung injury (SAP-ALI). However, lncRNA regulation networks related to SAP-ALI pathogenesis and drug treatment are unreported. In this study, lncRNAs and mRNAs in the lung tissue of SAP-ALI and control rats, with or without drug treatment (emodin or DEX), were assessed by RNA sequencing. Results showed both emodin and DEX were therapeutic for SAP-ALI and that mRNA and lncRNA levels differed between untreated and treated SAP-ALI rats. Gene expression profile relationships for emodin-treated and control rats were higher than DEX-treated and -untreated animals. By comparison of control and SAP-ALI animals, more up-regulated than down-regulated mRNAs and lncRNAs were observed with emodin treatment. For DEX treatment, more down-regulated than up-regulated mRNAs and lncRNAs were observed. Functional analysis demonstrated both up-regulated mRNA and co-expressed genes with up-regulated lncRNAs were enriched in inflammatory and immune response pathways. Further, emodin-associated lncRNAs and mRNAs co-expressed modules were different from those associated with DEX. Quantitative polymerase chain reaction demonstrates selected lncRNA and mRNA co-expressed modules were different in the lung tissue of emodin- and DEX-treated rats. Also, emodin had different effects compared with DEX on co-expression network of lncRNAs Rn60_7_1164.1 and AABR07062477.2 for the blue lncRNA module and Nrp1 for the green mRNA module. In conclusion, this study provides evidence that emodin may be a suitable alternative or complementary medicine for treating SAP-ALI.     

Differential expression of long noncoding RNAs in congenital microtia

ObjectiveTo analyse lncRNA expression profiles in microtia using bioinformatics analysis.MethodsWe examined lncRNA expression profiles in residual ear cartilage and normal ear cartilage from individual congenital microtia patients.ResultsThe gene chips used in this study included 30586 lncRNAs and 26109 mRNA probes. Intotal, 180 lncRNAs with differential expression weredetected in the residual ear cartilage compared with the normal cartilage, including 74 up-regulated and 106down-regulated lncRNAs. Signalling pathway analysis highlighted glyceride metabolism, osteoclast differentiation, andtumour growth. The results of qRT-PCR analysis were consistent with those of themicroarray.ConclusionDifferential expression of lncRNAs occurs in microtia. These lncRNAs and related signalling pathways may play an important role in the occurrence and development ofmicrotia.     

胃癌多药耐药相关microRNA的筛选和鉴定

目的:研究胃癌多药耐药相关microRNA并对其进行鉴定、靶基因预测和预测靶基因的生物信息学分析。方法:运用microRNA芯片对胃癌多药耐药细胞SGC7901/ADR和其亲本细胞SGC7901进行microRNA表达谱分析;采用实时定量PCR的方法对差异表达的miRNA进行验证;再运用生物信息学方法对差异表达的miRNA进行靶基因预测;再对预测的靶基因进行GO和KEGG通路分析。结果:与SGC7901相比SGC7901/ADR表达上调超过2倍的miRNA有6个,表达下调超过2倍的有11个。实时定量PCR对共同差异表达的microRNA进行验证显示与芯片结果的一致性。对这17个差异表达的miRNA进行靶基因预测,再对预测得到的靶基因进行GO和KEGG通路分析显示预测的靶基因参与了肿瘤相关通路、MAPK通路、Focal Adhesion通路等。结论:我们初步筛选得到了胃癌多药耐药相关miRNA并对其进行了生物信息学分析,为进一步地探索miRNA在胃癌多药耐药中的作用及其分子机制奠定了基础。     

捻转血矛线虫丙硫咪唑耐药相关lncRNA的转录组学测序与分析

分析捻转血矛线虫敏感株和耐药株中长链非编码RNA (Long non-coding RNA,lncRNA)的表达谱,探讨lncRNA与捻转血矛线虫丙硫咪唑耐药机制的关联性,为捻转血矛线虫耐药机理提供依据。文中对捻转血矛线虫敏感株和耐药株进行cDNA测序文库构建,使用Illumina HiSeq 4000平台进行双端测序,筛选出差异的lncRNA,基于顺式调控(cis)和反式调控(trans)对差异显著的lncRNA进行靶基因预测,并对靶基因进行过Gene Ontology (GO)功能注释和KEGG Pathway富集分析,利用FPKM法估计lncRNA和mRNA的表达水平。结果表明,敏感株和耐药株候选lncRNA分别为6 377和6 356个,两个文库中筛选出168个差异显著的lncRNA,其中在敏感株中表达上调有92个,表达下调76个。筛选得到的差异显著lncRNA候选靶基因416个,这些基因共注释到641条GO terms和92条信号通路;其中富集到耐药性相关的通路有药物代谢-其他酶、药物代谢-细胞色素P450、细胞色素P450对异生素的代谢等。综上表明,部分lncRNA介导的靶基因与捻转血矛线虫丙硫咪唑耐药性相关,lncRNA在捻转血矛线虫耐药性中具有潜在的重要的调节作用。探究了对于敏感虫株和耐药虫株中lncRNA的表达谱,发现了敏感虫株和耐药虫株中差异表达的lncRNA,有助于找出捻转血矛线虫如何抵抗丙硫咪唑的发生机制,为探讨捻转血矛线虫丙硫咪唑耐药机制提供科学的依据。     

LncRNA CASC11 promoted gastric cancer cell proliferation,migration and invasion in vitro by regulating cell cycle pathway

In this study, we aimed to investigate the effects of lncRNA CASC11 on gastric cancer (GC) cell progression through regulating miR-340-5p and cell cycle pathway. Expressions of lncRNA CASC11 in gastric cancer tissues and cell lines were determined by qRT-PCR. Differentially expressed lncRNAs, mRNAs and miRNAs were screened through microarray analysis. The relationship among CASC11, CDK1 and miR-340-5p was predicted by TargetScan and validated through dual luciferase reporter assay. Western blot assay examined the protein level of CDK1 and several cell cycle regulatory proteins. GO functional analysis and KEGG pathway analysis were used to predict the association between functions and related pathways. Cell proliferation was determined by CCK-8 assays. Cell apoptosis and cell cycle were detected by flow cytometry assay. CASC11 was highly expressed in GC tissues and cell lines. Knockdown of CASC11 inhibited GC cell proliferation, promoted cell apoptosis and blocked cell cycle. KEGG further indicated an enriched cell cycle pathway involving CDK1. QRT-PCR showed that miR-340-5p was down-regulated in GC cells tissues, while CDK1 was up-regulated. Furthermore, CASC11 acted as a sponge of miR-340-5p which directly targeted CDK1. Meanwhile, miR-340-5p overexpression promoted GC cell apoptosis and induced cell cycle arrest, while CDK1 overexpression inhibited cell apoptosis and accelerated cell cycle. Our study revealed the mechanism of CASC11/miR-340-5p/CDK1 network in GC cell line, and suggested that CASC11 was a novel facilitator that exerted a biological effect by activating the cell cycle signaling pathway. This finding provides a potential therapeutic target for GC.     

Sunitinib Reverse Multidrug Resistance in Gastric Cancer Cells by Modulating Stat3 and Inhibiting P-gp Function

Sunitinib, a small-molecule multi-targeted tyrosine kinase inhibitor, has been applied in phase II clinical trial as second-line treatment for advanced gastric cancer. In this study, we determined the effect of Sunitinib on the multidrug resistance in gastric cancer cells selected by vincristine. Our results showed that Sunitinib significantly enhanced the cytotoxicity of adriamycin, vincristine, etoposide, 5-Fluorouracil, and cisplatin in multidrug-resistant gastric cancer cells (SGC7901/VCR). Sunitinib significantly increased the intracellular accumulation and retention of rhodamine 123 in the SGC7901/VCR cells. However, Sunitinib, at a concentration that reverses MDR, had no significant effect on P-gp protein or mRNA expression levels. In addition, the present study revealed that Sunitinib inhibited Stat3 and down-regulated Bcl-2 in SGC7901/VCR cells, which might also contribute to the reversal of MDR. In conclusion, Sunitinib reverses multidrug resistance in gastric cancer cells by inhibiting P-gp transporter function and modulating Stat3 and Bcl-2. Further study with Sunitinib may be helpful for developing combination therapeutic strategy or circumventing gastric cancer MDR to other conventional anti-cancer drugs.     

Senescence-associated Long Non-coding RNA (SALNR) Delays Oncogene-induced Senescence through NF90 Regulation

Long non-coding RNAs (lncRNAs) have recently emerged as key players in many physiologic and pathologic processes. Although many lncRNAs have been identified, few lncRNAs have been characterized functionally in aging. In this study, we used human fibroblast cells to investigate genome-wide lncRNA expression during cellular senescence. We identified 968 down-regulated lncRNAs and 899 up-regulated lncRNAs in senescent cells compared with young cells. Among these lncRNAs, we characterized a senescence-associated lncRNA (SALNR), whose expression was reduced during cellular senescence and in premalignant colon adenomas. Overexpression of SALNR delayed cellular senescence in fibroblast cells. Furthermore, we found that SALNR interacts with NF90 (nuclear factor of activated T-cells, 90 kDa), an RNA-binding protein suppressing miRNA biogenesis. We demonstrated that NF90 is a SALNR downstream target, whose inhibition led to premature senescence and enhanced expressions of senescence-associated miRNAs. Moreover, our data showed that Ras-induced stress promotes NF90 nucleolus translocation and suppresses its ability to suppress senescence-associated miRNA biogenesis, which could be rescued by SALNR overexpression. These data suggest that lncRNA SALNR modulates cellular senescence at least partly through changing NF90 activity.     

Ribosomal proteins S13 and L23 promote multidrug resistance in gastric cancer cells by suppressing drug-induced apoptosis

Ribosomal proteins (RP) S13 and RPL23 were previously identified as two upregulated genes in a multidrug-resistant gastric cancer cell line SGC7901/VCR compared to its parental cell SGC7901 by differential display PCR. The aim of this study was to explore the roles of RPS13 and RPL23 in multidrug resistance (MDR) in gastric cancer cells. RPS13 and RPL23 were genetically overexpressed in SGC7901 cells, respectively. Either RPS13 or RPL23 enhanced resistance of SGC7901 cells to vincristine, adriamycin, and 5-fludrouracil. RPL23 also enhanced resistance of SGC7901 cells to cisplatin. Overexpression of either RPS13 or RPL23 did not alter the population doubling time, [³H]leucine incorporation, and intracellular adriamycin accumulation of SGC7901 cells. However, either RPS13 or RPL23 could protect SGC7901 cells from undergoing vincristine-induced apoptosis. Western blot analysis revealed that both RPS13 and RPL23 significantly increased the expression level of Bcl-2 and Bcl-2/Bax ratio in SGC7901 cells. In addition, overexpression of RPL23 enhanced glutathione S-transferase (GST) activity and intracellular glutathione content in SGC7901 cells. Together, this work demonstrates that either RPS13 or RPL23 can promote MDR in gastric cancer cells by suppressing drug-induced apoptosis, and that RPL23 may also promote MDR in gastric cancer cells through regulation of glutathione S-transferase-mediated drug-detoxifying system.     

应用蛋白质组学技术筛选胃癌耐药相关蛋白质

胃癌多药耐药性是临床胃癌化疗失败最主要的原因之一,但其分子机制仍然不太清楚.为了寻找新的胃癌耐药相关的蛋白质,揭示胃癌多药耐药的分子机制,以胃癌细胞SGC7901和长春新碱诱导的耐药胃癌细胞SGC7901/VCR为研究对象,应用二维凝胶电泳(two-dimensionalelectrophoresis,2-DE)技术分离两种细胞的总蛋白质,图像分析识别差异表达的蛋白质点,基质辅助激光解吸电离飞行时间质谱(matrix-assistedlaserdesorption/ionizationtimeofflightmassspectrometry,MALDI-TOF-MS)及电喷雾电离串联质谱(electrosprayionizationtandemmassspectrometry,ESI-Q-TOF)对差异表达的蛋白质点进行鉴定,蛋白质印迹和实时RT-PCR验证部分差异蛋白质在两株细胞中的表达水平,反义核酸转染技术分析HSP27(heatshockprotein27,HSP27)高表达与SGC7901/VCR耐药的相关性.得到了分辨率较高、重复性较好的两株细胞系的二维凝胶电泳图谱,质谱分析共鉴定了24个差异蛋白质点,蛋白质印迹和实时RT-PCR验证了部分差异蛋白的表达水平,反义寡核苷酸抑制HSP27表达能增加SGC7901/VCR对长春新碱的敏感性.研究结果不仅提示这些差异蛋白质如HSP27,Sorcin等可能与胃癌的多药耐药相关,而且为揭示胃癌细胞的多药耐药性产生机制提供了线索.