Search

BackgroundThis study aimed to explore the potential regulatory mechanisms of brain metastasis and to identify novel underlying targets of lung cancer with brain metastasis.MethodsExosomes were isolated from the plasma of lung cancer patients with or without brain metastasis and low or high metastatic lung cancer cells, and small RNA from plasma-derived exosomes were sequenced. Differentially expressed miRNAs (DE-miRNAs) were identified. Human brain microvascular endothelial cells (HBMECs) were transfected with miR-550a-3-5p mimics or inhibitors and exosomes. Cell viability, migration, and apoptosis/cycle were determined using Cell Counting Kit-8 (CCK-8), Transwell, and flow cytometry, respectively. Western blotting was used to measure the expression of the associated proteins. Finally, a dual-luciferase reporter gene assay was performed to confirm the miR-550a-3-5p target.ResultsTransmission electron microscopy, NanoSight, and western blotting showed that exosomes were successfully isolated and cell-derived exosomes could be taken up by HBMECs. Sequencing identified 22 DE-miRNAs which were enriched in the MAPK, chemokine, PPAR, and Wnt signaling pathways. MiR-550a-3-5p was significantly enriched in brain metastatic exosomes. Cellular experiments showed that miR-550a-3-5p and exosome enrichment significantly inhibited cell viability and migration, promoted apoptosis, and regulated the cell cycle of HBMECs compared with the controls (P P ConclusionOur results indicate that miR-550a-3-5p and YAP1 may be novel potential targets for controlling brain metastasis.

Eukaryotic translation initiation factor 4 gamma 1 (EIF4G1), as the key component of the transcription initiation factor complex EIF4F, is significantly upregulated in multiple solid tumours, including lung cancer. However, the function and mechanism of EIF4G1 in the regulation of non‐small‐cell lung cancer (NSCLC) remain unclear. Here, using the clinical samples and the comprehensive survival analysis platforms Kaplan‐Meier plotter, we observed aberrant upregulation of EIF4G1 in NSCLC tissues; furthermore, high expression of EIF4G1 showed association with low differentiation of lung cancer cells and poor overall survival in NSCLC patients. Non‐small‐cell lung cancer cell line A549 and H1703 stably infected with EIF4G1 shRNA were used to determine the function of EIF4G1 in regulating cell proliferation and tumorigenesis in vitro and in vivo. The results demonstrated that EIF4G1 promoted the G1/S transition of the cell cycle and tumour cell proliferation in non‐small cell lung cancer. Mechanistically, EIF4G1 was found to regulate the expression and phosphorylation of mTOR (Ser2448), which mediates the tumorigenesis‐promoting function of EIF4G1. The inhibition of mTOR attenuated the EIF4G1‐induced development and progression of tumours. These findings demonstrated that EIF4G1 is a new potential molecular target for the clinical treatment of non‐small cell lung cancer.

Cancer stem cells (CSCs) contribute to the cancer initiation, metastasis and drug resistance in non-small cell lung cancer (NSCLC). Herein, we identified a miR-221/222 cluster as a novel regulator of CSCs in NSCLC. Targeted overexpression or knockdown of miR-221/222 in NSCLC cells revealed the essential roles of miR-221/222 in regulation of lung cancer cell proliferation, mammosphere formation, subpopulation of CD133+ CSCs and the expression of stemness genes including OCT4, NANOG and h-TERT. The in vivo animal study showed that overexpression of miR-221/222 significantly enhanced the capacity of lung cancer cells to develop tumor and grow faster, indicating the importance of miR-221/222 in tumorigenesis and tumor growth. Mechanistically, Reck was found to be a key direct target gene of miR-221/222 in NSCLC. Overexpression of miR-221/222 significantly suppressed Reck expression, activated Notch1 signaling and increased the level of NICD. As an activated form of Notch1, NICD leads to enhanced stemness in NSCLC cells. In addition, knockdown of Reck by siRNA not only mimicked miR-221/222 effects, but also demonstrated involvement of Reck in the miR-221/222-induced activation of Notch1 signaling, verifying the essential roles of the miR-221/222-Reck-Notch1 axis in regulating stemness of NSCLC cells. These findings uncover a novel mechanism by which lung CSCs are significantly manipulated by miR-221/222, and provide a potential therapeutic target for the treatment of NSCLC.

Background Ferroptosis is a recently recognized non-apoptotic cell death that is distinct from the apoptosis, necroptosis and pyroptosis. Considerable studies have demonstrated ferroptosis is involved in the biological process of various cancers. However, the role of ferroptosis in esophageal adenocarcinoma (EAC) remains unclear. This study aims to explore the ferroptosis-related genes (FRG) expression profiles and their prognostic values in EAC. Methods The FRG data and clinical information were downloaded from The Cancer Genome Atlas (TCGA) database. Univariate and multivariate cox regressions were used to identify the prognostic FRG, and the predictive ROC model was established using the independent risk factors. GO and KEGG enrichment analyses were performed to investigate the bioinformatics functions of significantly different genes (SDG) of ferroptosis. Additionally, the correlations of ferroptosis and immune cells were assessed through the single-sample gene set enrichment analysis (ssGSEA) and TIMER database. Finally, SDG were verified in clinical EAC specimens and normal esophageal mucosal tissues. Results Twenty-eight significantly different FRG were screened from 78 EAC and 9 normal tissues. Enrichment analyses showed these SDG were mainly related to the iron-related pathways and metabolisms of ferroptosis. Gene network demonstrated the TP53, G6PD, NFE2L2 and PTGS2 were the hub genes in the biology of ferroptosis. Cox regression analyses demonstrated four FRG (CARS1, GCLM, GLS2 and EMC2) had prognostic values for overall survival (OS) (all P Conclusions We identified differently expressed ferroptosis-related genes that may involve in EAC. These genes have significant values in predicting the patients’ OS and targeting ferroptosis may be an alternative for therapy. Further studies are necessary to verify these results of our study.

MicroRNAs (miRNAs) loss-of-function phenotypes are mainly induced by chemically modified antisense oligonucleotides. Here we develop an alternative inhibitor for miRNAs, termed ‘small RNA zipper'. It is designed to connect miRNA molecules end to end, forming a DNA–RNA duplex through a complementary interaction with high affinity, high specificity and high stability. Two miRNAs, miR-221 and miR-17, are tested in human breast cancer cell lines, demonstrating the 70∼90% knockdown of miRNA levels by 30–50 nM small RNA zippers. The miR-221 zipper shows capability in rescuing the expression of target genes of miR-221 and reversing the oncogenic function of miR-221 in breast cancer cells. In addition, we demonstrate that the miR-221 zipper attenuates doxorubicin resistance with higher efficiency than anti-miR-221 in human breast cancer cells. Taken together, small RNA zippers are a miRNA inhibitor, which can be used to induce miRNA loss-of-function phenotypes and validate miRNA target genes., MicroRNAs regulate a wide range of biological processes and being able to inhibit their function could allow the development of therapeutic options. Here the authors describe a ‘small RNA zipper' that sequesters miRNAs by forming a chain of DNA:RNA duplexes.

Adult heart has limited potential for regeneration after pathological injury due to the limited cell proliferation of cardiomyocytes and the quiescent status of progenitor cells. As such, induction of cell-cycle reentry of cardiomyocytes is one of the key strategies for regeneration of damaged heart. In this study, a subset of miRNAs including miR-708 were identified to be much more abundant in the embryonic and neonatal cardiomyocytes than that in adult rodents. Overexpression of miR-708 promoted cellular proliferation of H9C2 cells or primary cardiomyocytes from neonatal rats or mice in vitro. Lipid nanoparticle delivery of miR-708 promoted myocardial regeneration and heart function recovery in vivo. In addition, miR-708 protected cardiomyocytes against stress-induced apoptosis under hypoxia or isoproterenol treatments. miR-708 inhibited the expression of MAPK14, which has been demonstrated arresting the cell cycle in cardiomyocytes. The cell proliferation-promoting function of miR-708 was dependent at least partly on the expression of MAPK14. These findings strengthen the potential of applying miRNAs to reconstitute lost cardiomyocytes in injured hearts, and may provide a novel miRNA candidate for promoting heart regeneration.

Triple-negative breast cancers (TNBC) are more aggressive due to lacking receptors for hormone therapy and maintaining stemness features in cancer cells. Herein we found long non-coding RNA CCAT2 overexpressed specially in TNBC, and in breast cancer stem cells (BCSC) as well. Enforced overexpression and targeted knockdown demonstrated the oncogenic function of CCAT2 both in vitro and in vivo. CCAT2 promoted the expression of stemness markers including OCT4, Nanog and KLF4, increased mammosphere formation and induced ALDH+ cancer stem cell population in TNBC. A chromosomally adjacent gene OCT4-PG1, as a pseudogene of OCT4, was upregulated by CCAT2, and positively regulated the stemness features of TNBC cells. miR-205 was identified as a target gene of CCAT2 in TNBC. Point-mutation in CCAT2 impaired the sponge inhibition of miR-205. Overexpression of miR-205 rescued the oncogenic phenotypes induced by CCAT2. In addition, Notch2, as a target gene of miR-205, was downregulated by miR-205 and upregulated by CCAT2 in TNBC. Collectively, the current study revealed a novel function of CCAT2 in promoting tumor initiation and progression in TNBC through upregulating OCT4-PG1 expression and activating Notch signaling. These findings not only demonstrated a lncRNA-based therapeutic strategy in treatment of TNBC, but also added a node to the regulatory network of CCAT2 that controls aggressiveness of breast cancer stem cells.

Background: Genetic classification of breast cancer based on the coding mRNA suggests the evolution of distinct subtypes. Whether the non-coding genome is altered concordantly with the coding genome and the mechanism by which the cell cycle directly controls the non-coding genome is poorly understood. Methods: Herein, the miRNA signature maintained by endogenous cyclin D1 in human breast cancer cells was defined. In order to determine the clinical significance of the cyclin D1-mediated miRNA signature, we defined a miRNA expression superset from 459 breast cancer samples. We compared the coding and non-coding genome of breast cancer subtypes. Results: Hierarchical clustering of human breast cancers defined four distinct miRNA clusters (G1-G4) associated with distinguishable relapse-free survival by Kaplan-Meier analysis. The cyclin D1-regulated miRNA signature included several oncomirs, was conserved in multiple breast cancer cell lines, was associated with the G2 tumor miRNA cluster, ERα+ status, better outcome and activation of the Wnt pathway. The coding and non-coding genome were discordant within breast cancer subtypes. Seed elements for cyclin D1-regulated miRNA were identified in 63 genes of the Wnt signaling pathway including DKK. Cyclin D1 restrained DKK1 via the 3'UTR. In vivo studies using inducible transgenics confirmed cyclin D1 induces Wnt-dependent gene expression. Conclusion: The non-coding genome defines breast cancer subtypes that are discordant with their coding genome subtype suggesting distinct evolutionary drivers within the tumors. Cyclin D1 orchestrates expression of a miRNA signature that induces Wnt/β-catenin signaling, therefore cyclin D1 serves both upstream and downstream of Wnt/β-catenin signaling. Published version

Less than 2% of the human genome DNA is composed of protein-coding genes, although the majority of the human genome is transcribed, indicating the transcripts mostly are noncoding RNAs. Those noncoding RNAs with length between 200 nt and 200 kb are categorized as long noncoding RNA (lncRNA). Around 30 000 lncRNAs have been predicted or identified, although little is known regarding the regulatory function for a vast majority of these sequences. Emerging evidence demonstrated that lncRNAs play crucial roles in regulation of many cancer types, including breast cancer, serving as oncogenes or tumor suppressors. Aberrant and differential expression of lncRNA in breast cancer has been frequently reported. Their regulation of breast cancer is still the beginning to be elucidated. This review collected those experimentally validated lncRNAs in human breast cancer, summarizing their biological function as well as the regulatory mechanism. In addition, the potential of lncRNAs as biomarkers for better diagnosis or therapeutic targets for cancer treatment was discussed.

// Zuoren Yu 1,2 , Zengguang Xu 1 , Gabriele DiSante 2 , Jennifer Wright 2 , Min Wang 2 , Yuan Li 1 , Qian Zhao 1 , Tao Ren 1 , Xiaoming Ju 2 , Ellen Gutman 2 , Guangxue Wang 1 , Sankar Addya 2 , Tieyan Li 1 , Zhendong Xiang 3 , Chenguang Wang 2 , Xiongfei yang 3 , Xiaolai Yang 3 , Richard Pestell 2 1 Research Center for Translational Medicine, Key Laboratory of Arrhythmias of the Ministry of Education, East Hospital, Tongji University School of Medicine, Shanghai, China, 2 Departments of Cancer Biology, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia PA 3 People’s Hospital of Gansu Province, Lanzhou, China Correspondence: Richard G. Pestell, email: // Zuoren Yu, email: // Keywords : miR-17/20, breast cancer, AKT, apoptosis Received : January 29, 2014 Accepted : March 2, 2014 Published : March 4, 2014 Abstract The serine threonine kinase Akt1 has been implicated in the control of cellular metabolism, survival and growth. Herein, disruption of the ubiquitously expressed member of the Akt family of genes, Akt1, in the mouse, demonstrates a requirement for Akt1 in miRNA-mediated cellular apoptosis. The miR-17/20 cluster is known to inhibit breast cancer cellular proliferation through G1/S cell cycle arrest via binding to the cyclin D1 3’UTR. Here we show that miR-17/20 overexpression sensitizes cells to apoptosis induced by either Doxorubicin or UV irradiation in MCF-7 cells via Akt1. miR-17/20 mediates apoptosis via increased p53 expression which promotes Akt degradation. Akt1 -/- mammary epithelial cells which express Akt2 and Akt3 demonstrated increased apoptosis to DNA damaging agents. Akt1 deficiency abolished the miR-17/20-mediated apoptosis. These results demonstrated a novel pathway through which miR17/20 regulate p53 and Akt controlling breast cancer cell apoptosis.

Background Concerted hormone secretion is essential for glucose homeostasis and growth. The oocyte testis gene 1 (Otg1) has limited information in mammals before. Human OTG1 has been identified as an antigen associated with cutaneous T cell lymphoma, while worm Otg1 is recently reported to be a vesicle trafficking regulator in neurons. To understand the physiological role of Otg1 and its potential relation to hormone secretion, we characterized a mutation caused by the piggyBac transposon (PB) insertion in mice. Results Oocyte testis gene 1 encodes a Golgi localized protein that is expressed with a broad tissue distribution in mice. The PB insertion effectively blocks Otg1 expression, which results in postnatal lethality, growth retardation, hypoglycemia and improved insulin sensitivity in mice. Otg1 mutants exhibit decreased levels of insulin, leptin and growth hormone in the circulation and reduced hepatic IGF-1 expression. Decreased expression of Otg1 in pituitary GH3 cells causes reduced grow hormone expression and secretion, as well as the traffic of the VSVG protein marker. Conclusions Our data support the hypothesis that Otg1 impacts hormone secretion by regulating vesicle trafficking. These results revealed a previously unknown and important role of Otg1 in hormone secretion and glucose homeostasis in mammals. Electronic supplementary material The online version of this article (doi:10.1186/s13578-016-0108-4) contains supplementary material, which is available to authorized users.

Circulating miRNAs are protected from ribonuclease degradation by assembly into microvesicles and exosomes. Releasing miRNAs completely from these particles is the key step to quantify the circulating miRNAs. Currently purified RNA-based quantitative analysis is widely used while it is time and cost consuming with high risk for those circulating miRNAs with low abundance due to partial loss of RNA during the steps of total RNA extraction and small RNA enrichment. Herein, we optimized a simple, effective and time-saving method to directly measure plasma miRNAs without RNA isolation. It is based on complete miRNA release from the protein complexes, followed by miRNA-specific reverse transcription and quantitative real-time PCR amplification. By comparison to the RNA-based approach, the direct quantification method showed more efficiency for circulating miRNA analysis, higher accuracy and specificity. By application of the direct quantification method to clinical samples combined with the RNA-based miRNA screening analysis, upregulation of miR-106a in blood was validated in metastatic breast cancer patients, indicating miR-106a are a potential biomarker for metastatic breast cancer.

MicroRNAs (miRNAs) are thought to regulate tumor progression and metastasis via direct interaction with target genes within cells. Emerging evidence has demonstrated the secretion of miRNAs into environment via cancer cell exosomes, called "exosomal shuttle small RNA". Microenvironmental miRNAs are important mediators of cell-to-cell communication, and they play important roles in regulating cancer metastasis. RNA analysis indicates enrichment of the miRNA population in cell-culturing medium. miRNA-conditioned medium is able to mediate the function of miRNAs in regulating cancer cell migration and invasion. Here we combine our recent work with literature discussing multiple mechanisms through which exosomal miRNAs regulate cancer cell migration, invasion and metastasis. We summarize a heterotypic signaling pathway by which miRNA regulates the cellular secretion and tumor microenvironment in control of breast cancer cell migration and invasion. In conclusion, exosomal miRNAs are able to regulate cancer metastasis via heterotypic signals in the microenvironment.

Fluorescent proteins provide a powerful means to track gene expression and cellular behaviors in the study of model organisms such as mice. Among the new generation of fluorescent protein markers, the monomeric red fluorescent protein mRFP1 is particularly attractive because of its rapid maturation and minimal interference with GFP and GFP-derived markers. Here we evaluate the utility of mRFP1 as a marker in transgenic mice. We show that high level and ubiquitous expression of mRFP1 does not affect mouse development, general physiology, or reproduction. mRFP1 expression can be readily detected with unaided eyes under daylight in transgenic mice on the albino background. The intensity of mRFP1 signals can be used to distinguish homozygous and heterozygous transgenic mice. Together, these features make mRFP1 an attractive marker for broad applications in transgenic research. genesis 42:86–90, 2005. © 2005 Wiley-Liss, Inc.