BackgroundOxaliplatin resistance is a major challenge for treatment of advanced colorectal cancer (CRC). Both acquisition of epithelial-mesenchymal transition (EMT) and suppressed drug accumulation in cancer cells contributes to development of oxaliplatin resistance. Aberrant expression of small noncoding RNA, miR-128-3p, has been shown to be a key regulator in tumorigenesis and cancer development. However, its roles in the progression of CRC and oxaliplatin-resistance are largely unknown.MethodsOxaliplatin-resistant CRC and normal intestinal FHC cells were transfected with a miR-128-3p expression lentivirus. After transfection, FHC-derived exosomes were isolated and co-cultured with CRC cells. miR-128-3p expression in resistant CRC cells, FHC cells, and exosomes was quantified by quantitative real-time PCR (RT-qPCR). The mRNA and protein levels of miR-128-3p target genes in resistant CRC cells were quantified by RT-qPCR and western blot, respectively. The effects of miR-128-3p on CRC cell viability, apoptosis, EMT, motility and drug efflux were evaluated by CCK8, flow cytometry, Transwell and wound healing assays, immunofluorescence, and atomic absorption spectrophotometry. Xenograft models were used to determine whether miR-128-3p loaded exosomes can re-sensitize CRC cells to oxaliplatin in vivo.ResultsIn our established stable oxaliplatin-resistant CRC cell lines, in vitro and vivo studies revealed miR-128-3p suppressed EMT and increased intracellular oxaliplatin accumulation. Importantly, our results indicated that lower miR-128-3p expression was associated with poor oxaliplatin response in advanced human CRC patients. Moreover, data showed that miR-128-3p-transfected FHC cells effectively packaged miR-128-3p into secreted exosomes and mediated miR-128-3p delivery to oxaliplatin-resistant cells, improving oxaliplatin response in CRC cells both in vitro and in vivo. In addition, miR-128-3p overexpression up-regulated E-cadherin levels and inhibited oxaliplatin-induced EMT by suppressing Bmi1 expression in resistant cells. Meanwhile, it also decreased oxaliplatin efflux through suppressed expression of the drug transporter MRP5.ConclusionOur results demonstrate that miR-128-3p delivery via exosomes represents a novel strategy enhancing chemosensitivity in CRC through negative regulation of Bmi1 and MRP5. Moreover, miR-128-3p may be a promising diagnostic and prognostic marker for oxaliplatin-based chemotherapy.Electronic supplementary materialThe online version of this article (10.1186/s12943-019-0981-7) contains supplementary material, which is available to authorized users.
Recently, expression signatures of exosomal long non-coding RNAs (lncRNAs) have been proposed as potential non-invasive biomarkers for cancer detection. In this study, we aimed to develop a urinary exosome (UE)-derived lncRNA panel for diagnosis and recurrence prediction of bladder cancer (BC). Quantitative real-time polymerase chain reaction (qRT-PCR) was performed to screen and evaluate the expressions of eight candidate lncRNAs in a training set (208 urine samples) and a validation set (160 urine samples). A panel consisting of three differently expressed lncRNAs (MALAT1, PCAT-1 and SPRY4-IT1) was established for BC diagnosis in the training set, showing an area under the receiver-operating characteristic (ROC) curve (AUC) of 0.854. Subsequently, the performance of the panel was further verified with an AUC of 0.813 in the validation set, which was significantly higher than that of urine cytology (0.619). In addition, Kaplan-Meier analysis suggested that the up-regulation of PCAT-1 and MALAT1 was associated with poor recurrence-free survival (RFS) of non-muscle-invasive BC (NMIBC) (p < 0.001 and p = 0.002, respectively), and multivariate Cox proportional hazards regression analysis revealed that exosomal PCAT-1 overexpression was an independent prognostic factor for the RFS of NMIBC (p = 0.018). Collectively, our findings indicated that UE-derived lncRNAs possessed considerable clinical value in the diagnosis and prognosis of BC.Electronic supplementary materialThe online version of this article (10.1186/s12943-018-0893-y) contains supplementary material, which is available to authorized users.
The alveolar macrophage-derived peptide tumor necrosis factor-␣ (TNF␣) initiates pulmonary inflammation through its ability to stimulate interleukin-8 (IL-8) synthesis in alveolar epithelial cells through an incompletely described transcriptional mechanism. In this study, we use the technique of ligation-mediated polymerase chain reaction (LMPCR) to record changes in transcription factor occupancy of the IL-8 promoter after TNF␣ stimulation of A549 human alveolar cells. Using dimethylsulfate/LMPCR, no detectable proteins bind the TATA box in unstimulated cells. By contrast, TNF␣ rapidly induces protection of G residues at ؊79 and ؊80 coincident with endogenous IL-8 gene transcription. Using DNase I/LMPCR, we observe inducible protection of nucleotides ؊60 to ؊99 (the TNF response element) and nucleotides ؊3 to ؊32 (containing the TATA box). Surprisingly, extensive TATA box protection is only seen after TNF␣ stimulation. Using a two-step microaffinity isolation/Western immunoblot DNA binding assay, we observe that the NF-B subunits Rel A, NF-B1, and c-Rel inducibly bind the TNF response element; these proteins undergo rapid TNF␣-inducible increases in nuclear abundance as a consequence of IB␣ proteolysis. Furthermore, the peptide aldehyde N-acetyl-Leu-Leu-norleucinal, an agent that blocks both IB␣ proteolysis and NF-B subunit translocation, abrogates recombinant human TNF␣-inducible IL-8 gene transcription. These studies demonstrate that IL-8 is activated by a promoter recruitment mechanism in alveolar epithelial cells, where NF-B subunit translocation is required for (and coincident with) binding of the constitutively active TATA box-binding proteins.The respiratory epithelium contributes to normal pulmonary function in its ability to clear inhaled particulates through mucociliary action, ensure alveolar patency through surfactant secretion, and facilitate bacterial opsonization through secretory immunoglobulin production. A large body of evidence now supports an additional role for the airway epithelial cell to amplify cytokine signals from pathogen-activated alveolar macrophages into secretion of chemokines, arachidonic acid metabolites, and phospholipid-molecules that recruit additional inflammatory cells into the airway mucosa (1, 2). Of the potent alveolar macrophage-derived cytokines studied, the secretion of tumor necrosis factor ␣ (TNF␣), 1 in particular, has been implicated in the pathophysiology of neutrophilic-infiltrating disorders including acute lung injury from sepsis, silica-induced pulmonary fibrosis, allograph rejection, and acute respiratory tract infection (3-6).The peptide hormone TNF␣ activates signaling cascades by inducing trimerization of the airway epithelial cell-expressed 55-kDa TNF receptor type I (TNFR1). Liganded trimeric TNFR1, in turn, recruits TNF receptor-associated proteins (TRADD, FADD, TRAF2, and others) to its intracytoplasmic domain to generate intracellular signaling cascades via second messengers including ceramide, 1,2-diacylglycerol, and arachidonic acid metabolites (s...
Lung cancer is the first leading cause of cancer deaths worldwide. Non‐small cell lung cancer (NSCLC) is the most common type of lung cancer. Increasing evidence shows that long noncoding RNA (lncRNA) are capable of modulating tumor initiation, proliferation and metastasis. In the present study, we aimed to evaluate whether circulating lncRNA could be used as biomarkers for diagnosis and prognosis of NSCLC. Expression profiles of 14 lncRNA selected from other studies were validated in 20 pairs of tissues by quantitative real‐time PCR, and the dysregulated lncRNA thus identified were further validated in serum samples from two independent cohorts along with three tumor makers (CEA, CYFRA21‐1, and SCCA). Receiver‐operating characteristic analysis was utilized to estimate the diagnostic efficiency of the candidate lncRNA and tumor markers. Importantly, we observed an association between lncRNA expression and overall survival (OS) rate of NSCLC. The expressions of SOX2 overlapping transcript (SOX2OT) and ANRIL were obviously upregulated in NSCLC tissues and serum samples compared with normal controls (P < 0.01). Based on the data from the training set, we next used a logistic regression model to construct an NSCLC diagnostic panel consisting of two lncRNA and three tumor markers. The area under the curve of this panel was 0.853 (95% confidence interval = 0.804–0.894, sensitivity = 77.1%, specificity = 79.2%), and this was distinctly superior to any biomarker alone (all at P < 0.05). Similar results were observed in the validation set. Intriguingly, Kaplan–Meier analysis demonstrated that low expressions of SOX2OT and ANRIL were both associated with higher OS rate (P = 0.008 and 0.017, respectively), and SOX2OT could be used as an independent prognostic factor (P = 0.036). Taken together, our study demonstrated that the newly developed diagnostic panel consisting of SOX2OT, ANRIL, CEA, CYFRA21‐1, and SCCA could be valuable in NSCLC diagnosis. LncRNA SOX2OT and ANRIL might be ideal biomarkers for NSCLC prognosis.
Exosomes are small membrane vesicles released by many cells. These vesicles can mediate cellular communications by transmitting active molecules including long non‐coding RNAs (lncRNAs). In this study, our aim was to identify a panel of lncRNAs in serum exosomes for the diagnosis and recurrence prediction of bladder cancer (BC). The expressions of 11 candidate lncRNAs in exosome were investigated in training set (n = 200) and an independent validation set (n = 320) via quantitative real‐time PCR. A three‐lncRNA panel (PCAT‐1, UBC1 and SNHG16) was finally identified by multivariate logistic regression model to provide high diagnostic accuracy for BC with an area under the receiver‐operating characteristic curve (AUC) of 0.857 and 0.826 in training set and validation set, respectively, which was significantly higher than that of urine cytology. The corresponding AUCs of this panel for patients with Ta, T1 and T2‐T4 were 0.760, 0.827 and 0.878, respectively. In addition, Kaplan‐Meier analysis showed that non‐muscle‐invasive BC (NMIBC) patients with high UBC1 expression had significantly lower recurrence‐free survival (P = 0.01). Multivariate Cox analysis demonstrated that UBC1 was independently associated with tumour recurrence of NMIBC (P = 0.018). Our study suggested that lncRNAs in serum exosomes may serve as considerable diagnostic and prognostic biomarkers of BC.
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