LncRNA IPW inhibits growth of ductal carcinoma in situ by downregulating ID2 through miR-29c

Activation of the imprinted Prader-Willi Syndrome locus by CRISPR-based epigenome editing

Epigenome editing with DNA-targeting technologies such as CRISPR-dCas9 can be used to dissect gene regulatory mechanisms and potentially treat associated disorders. For example, Prader-Willi Syndrome (PWS) is caused by loss of paternally expressed imprinted genes on chromosome 15q11.2-q13.3, although the maternal allele is intact but epigenetically silenced. Using CRISPR repression and activation screens in human induced pluripotent stem cells (iPSCs), we identified genomic elements that control expression of the PWS gene SNRPN from the paternal and maternal chromosomes. We showed that either targeted transcriptional activation or DNA demethylation can activate the silenced maternal SNRPN and downstream PWS transcripts. However, these two approaches function at unique regions, preferentially activating different transcript variants and involving distinct epigenetic reprogramming mechanisms. Remarkably, transient expression of the targeted demethylase leads to stable, long-term maternal SNRPN expression in PWS iPSCs. This work uncovers targeted epigenetic manipulations to reprogram a disease-associated imprinted locus and suggests possible therapeutic interventions.

m6A-Mediated Upregulation of Imprinted in Prader-Willi Syndrome Induces Aberrant Apical-Basal Polarization and Oxidative Damage in RPE Cells

Purpose

To reveal the clinical significance, pathological involvement and molecular mechanism of imprinted in Prader-Willi syndrome (IPW) in RPE anomalies that contribute to AMD.

Methods

IPW expression under pathological conditions were detected by microarrays and qPCR assays. In vitro cultured fetal RPE cells were used to study the pathogenicity induced by IPW overexpression and to analyze its upstream and downstream regulatory networks.

Results

We showed that IPW is upregulated in the macular RPE-choroid tissue of dry AMD patients and in fetal RPE cells under oxidative stress, inflammation and dedifferentiation. IPW overexpression in fetal RPE cells induced aberrant apical-basal polarization as shown by dysregulated polarized markers, disrupted tight and adherens junctions, and inhibited phagocytosis. IPW upregulation was also associated with RPE oxidative damages, as demonstrated by intracellular accumulation of reactive oxygen species, reduced cell proliferation, and accelerated cell apoptosis. Mechanically, N6-methyladenosine level of the IPW transcript regulated its stability with YTHDC1 as the reader. IPW mediated RPE features by suppressing MEG3 expression to sequester its inhibition on the AKT serine-threonine kinase (AKT)/mammalian target of rapamycin (mTOR) pathway. We also noticed that the mTOR inhibitor rapamycin suppresses the AKT/mTOR pathway to alleviate the IPW-induced RPE anomalies.

Conclusions

We revealed that IPW overexpression in RPE induces aberrant apical-basal polarization and oxidative damages, thus contributing to AMD progression. We also annotated the upstream and downstream regulatory networks of IPW in RPE. Our findings shed new light on the molecular mechanisms of RPE dysfunctions, and indicate that IPW blockers may be a promising option to treat RPE abnormalities in AMD.

SMURF2 facilitates ubiquitin-mediated degradation of ID2 to attenuate lung cancer cell proliferation

SMAD-specific E3 ubiquitin protein ligase 2 (SMURF2) functions as either a tumor promoter or tumor suppressor in several tumors. However, the detailed effect of SMURF2 on non-small cell lung cancer has not been fully understood. In this study, SMURF2 expression and its diagnostic value were analyzed. Co-Immunoprecipitation (Co-IP), proximity ligation assay (PLA), chromatin immunoprecipitation (ChIP) and nude mice tumor-bearing model were applied to further clarify the role of SMURF2 in lung cancer. SMURF2 expression was reduced in the tumor tissues of patients with NSCLC and high SMURF2 expression was significantly correlated with favorable outcomes. Furthermore, the overexpression of SMURF2 significantly inhibited lung cancer cell progression. Mechanistically, SMURF2 interacted with inhibitor of DNA binding 2 (ID2), subsequently promoting the poly-ubiquitination and degradation of ID2 through the ubiquitin-proteasome pathway. Downregulated ID2 in lung cells dissociates endogenous transcription factor E2A, a positive regulator of the cyclin-dependent kinase inhibitor p21, and finally induces G1/S arrest in lung cancer cells. This study revealed that the manipulation of ID2 via SMURF2 may control tumor progression and contribute to the development of novel targeted antitumor drugs.

Long Noncoding RNA IPW Is a Novel Diagnostic and Predictive Biomarker in Lung Adenocarcinoma

Background: Long non-coding RNAs (lncRNAs), as functional components of the human genome, are widely involved in cell proliferation, differentiation, apoptosis, migration and invasion by several types of cancer, including lung cancer. However, the role of lncRNA IPW in lung cancer has not been fully elucidated. The aim of the present study was to characterize the expression and clinical significance of lncRNA IPW in lung cancer. Materials and Methods: IPW expression in tumor samples and cells was assessed using the Oncomine and Cancer Cell Line Encyclopedia (CCLE) database, respectively. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was used to determine IPW expression and microRNA-370 (miR-370) expression. The clinical significance of IPW was evaluated by Chi-square test and Kaplan-Meier pot analyses. In addition, the sulforhodamine blue (SRB) assays was used to detect cell proliferation in IPW-overexpressed A549 cells. Results: IPW expression was significantly down-regulated in NSCLC tissues and was significantly associated with many clinicopathological data, including smoking history, differentiation, pT factor, pN factor and pTNM stage (p < 0.05). Decreased IPW expression was correlated with poor survival (p = 1.5e-05) and was positively associated with first progression in patients with lung adenocarcinoma (p = 0.00041). Furthermore, IPW could inhibit A549 cell proliferation and expression of miR-370. High miR-370 expression was associated with poor overall survival (OS) among lung adenocarcinoma patients (p = 0.045). Conclusions: These findings provide evidence that down-regulation of IPW might be considered as a beneficial prognostic biomarker and that it could potentially serve as therapeutic target in lung adenocarcinoma.

RP11-79H23.3 Inhibits the Proliferation and Metastasis of Non-small-cell Lung Cancer Through Promoting miR-29c

Evidences indicate that long non-coding RNAs (lncRNAs) are closely involved and contributed to tumorigenesis and cancer progression. As a novel lncRNA, RP11-79H23.3 was found to be an anti-oncogene in bladder cancer. However, the essential roles and functions of RP11-79H23.3 in non-small-cell lung cancer (NSCLC) remains to be elucidated. Here, loss of functional assay was applied to gain insights into the functions of RP11-79H23.3 on the proliferation and metastasis capabilities of A549 and H1299 cells. Meantime, Real-time PCR was utilized to measure RP11-79H23.3 and miR-29c expression in NSCLC tissues. Dual-luciferase reporter assay, CCK8, colony formation assay, transwell and Western blot were performed to illustrate the potential molecular basis of RP11-79H23.3 in NSCLC. RP11-79H23.3 downregulation facilitated cell proliferation, migration, and invasion of NSCLC. The result of dual-luciferase reporter assay represented a direct interaction of RP11-79H23.3 with miR-29c, which suppressed miR-29c expression that showed inversely correlation in NSCLC. Moreover, RP11-79H23.3 siRNA facilitated the progression of NSCLC partially via regulating the expression of miR-29c and the activation of Wnt/β-catenin signaling pathway. Our findings highlighted that RP11-79H23.3, served as an anti-oncogene, accelerated NSCLC progression through sequestering miR-29c, providing a promising therapeutic target for NSCLC.

LncRNA ENST869 Targeting Nestin Transcriptional Region to Affect the Pharmacological Effects of Chidamide in Breast Cancer Cells

Breast cancer is one of the leading threats to the health of women. It has the highest incidence and mortality in women worldwide. Although progress has been made in the development and application of anti-breast cancer drugs such as Chidamide and others, the occurrence of drug resistance limits the effective application of chemotherapies. The purpose of this study is to explore the role of LncRNA in the pharmacological effect of Chidamide in breast cancer therapy. The human breast cancer MCF-7 or MDA-MB-231 cells were used as the research cell models. The RNA library screening and high-throughput sequencing comparative analysis was conducted. The binding of LncRNA and its downstream target genes in RNA and protein levels was tested. The results showed that the expression of LncRNA ENST869 in cells treated with Chidamide increased significantly, as demonstrated by real-time PCR and cell viability assay. RNAplex analysis showed that LncRNA ENST869 and Nestin mRNA may interact. RNA interference and Western blot analysis indicated that LncRNA ENST869 could target and regulate the expression of Nestin. Luciferase assay and RNA-protein pulldown showed that LncRNA ENST869 affected Nestin transcription. There might be a highly active binding region of LncRNA ENST869 in regulating Nestin transcriptional activity within the site of 250 bp upstream of the transcription starting point of Nestin. In addition, LncRNA ENST869 did not directly interact with Nestin protein to affect its activity. In conclusion, our results demonstrated that LncRNA ENST869 could affect the function of Nestin in breast cancer cells treated with Chidamide. Nestin is a key player in influencing the pharmacological activity of Chidamide and an essential factor in drug resistance of breast cancer cells.