STAT3-induced HLA-F-AS1 promotes cell proliferation and stemness characteristics in triple negative breast cancer cells by upregulating TRABD

Potentials as biomarker and therapeutic target of upregulated long non-coding RNA HLA-F antisense RNA 1 in hepatitis B virus-associated hepatocellular carcinoma

The tissue-specific characteristics have encouraged researchers to identify organ-specific lncRNAs as disease biomarkers. This study aimed to identify the clinical and functional roles of long non-coding RNA HLA-F antisense RNA 1 (HLA-F-AS1) in hepatitis B virus (HBV)-hepatocellular carcinoma (HCC). A total of 121 HBV-HCC, 81 chronic hepatitis B (CHB), and 85 normal liver tissues were evaluated in this study. Real-time quantitative PCR assay was used to evaluate the RNA expression levels. Performance in diagnosis was compared between alpha fetoprotein (AFP) and HLA-F-AS1 using Receiver Operating Characteristic (ROC) curves. Performance in post-hepatectomy prognosis with high or low HLA-F-AS1 was compared using Kaplan-Meier curves. Multi-variable analysis was used to determine the informative predictors. Downstream miRNAs for HLA-F-AS1 were predicted and miR-128-3p was confirmed by luciferase reporter assay and RNA pull-down assay. In vitro functional analysis was performed by MTS reagent for cell proliferation and transwell assay for cell migration. HLA-F-AS1 levels were significantly increased in the HBV-HCC compared to normal healthy tissue and CHB tissues. HLA-F-AS1 exhibited a well potential in making a distinction between HBV-HCC and health, as well as HBV-HCC and CHB. The survival analysis revealed that patients with high levels of HLA-F-AS1 tend to shorter overall survival times. The best prognostic performance was achieved by HLA-F-AS1 after multi-variable analysis (HR 2.290, 95% CI 1.191-4.403, p = 0.013). Functional analysis showed that HLA-F-AS1 promoted cell proliferation and migration via miR-128-3p. Up-regulation of HLA-F-AS1 could serve as a promising diagnostic and prognostic marker for HBV-HCC after surgery, maybe useful in the management of HBV-HCC patients. HLA-F-AS1 can promote the progression of HBV-HCC, may be useful in the targeting treatment of HBV-HCC patients.

MARS an improved de novo peptide candidate selection method for non-canonical antigen target discovery in cancer

Understanding the nature and extent of non-canonical human leukocyte antigen (HLA) presentation in tumour cells is a priority for target antigen discovery for the development of next generation immunotherapies in cancer. We here employ a de novo mass spectrometric sequencing approach with a refined, MHC-centric analysis strategy to detect non-canonical MHC-associated peptides specific to cancer without any prior knowledge of the target sequence from genomic or RNA sequencing data. Our strategy integrates MHC binding rank, Average local confidence scores, and peptide Retention time prediction for improved de novo candidate Selection; culminating in the machine learning model MARS. We benchmark our model on a large synthetic peptide library dataset and reanalysis of a published dataset of high-quality non-canonical MHC-associated peptide identifications in human cancer. We achieve almost 2-fold improvement for high quality spectral assignments in comparison to de novo sequencing alone with an estimated accuracy of above 85.7% when integrated with a stepwise peptide sequence mapping strategy. Finally, we utilize MARS to detect and validate lncRNA-derived peptides in human cervical tumour resections, demonstrating its suitability to discover novel, immunogenic, non-canonical peptide sequences in primary tumour tissue.

A feedback loop between lncRNA MALAT1 and DNMT1 promotes triple-negative breast cancer stemness and tumorigenesis

BACKGROUND

The function of long non-coding RNA (lncRNA) MALAT1 in regulating triple-negative breast cancer (TNBC) stemness and tumorigenesis was investigated.

METHODS

Sphere formation and colony formation assays coupled with flow cytometry were employed to evaluate the percentage of CD44high/CD44low cells, and ALDH+ cells were performed to evaluate the stemness. Bisulfite sequencing PCR (BSP) was employed to detect the methylation level of MALAT1. Tumor xenograft experiment was performed to evaluate tumorigenesis in vivo. Finally, dual-luciferase reporter and RIP assays were employed to verify the binding relationship between MALAT1 and miR-137.

RESULTS

Our results revealed that MALAT1 and BCL11A were highly expressed in TNBC, while miR-137 and DNMT1 were lowly expressed. Our results proved that MALAT1 positively regulated BCL11A expression through targeting miR-137. Functional experiments revealed that MALAT1 inhibited DNMT1 expression through acting on the miR-137/BCL11A pathway to enhance TNBC stemness and tumorigenesis. We also found that high MALAT1 expression in TNBC was related to the DNMT1-mediated hypomethylation of MALAT1. As expected, DNMT1 overexpression could remarkably inhibit TNBC stemness and tumorigenesis, which was eliminated by MALAT1 overexpression.

CONCLUSION

MALAT1 downregulated DNMT1 by miR-137/BCL11A pathway to enhance TNBC stemness and tumorigenesis; meanwhile, DNMT1/MALAT1 formed a positive feedback loop to continuously promote TNBC malignant behaviors.

LINC02532 by Mediating miR-541-3p/HMGA1 Axis Exerts a Tumor Promoter in Breast cancer

The newly discovered LINC02532 is abnormally expressed in a variety of cancers and promotes cancer progression. The research proposed to discover the biological and molecular mechanisms of LINC02532 in breast cancer (BCa). In the resected BCa tissue samples and adjacent normal tissues, LINC02532, miR-541-3p, and High Mobility Group A1 (HMGA1) levels were determined. Cell function experiments were carried out on the premise of cell transfection with relevant plasmids. Based on that, the influence of LINC02532, miR-541-3p, and HMGA1 on MCF-7 cell activities (proliferation, migration, invasion, cell cycle, and apoptosis) was determined, as well as on EMT. Additionally, animal experiments were allowed to support cell experimental conclusions on LINC02532. Finally, the mechanistic network of LINC02532, miR-541-3p, and HMGA1 was identified. It was BCa tissues highly expressing LINC02532 and HMGA1, while lowly expressing miR-541-3p. Functionally, LINC02532 depletion repressed the activities and EMT process of MCF-7 cells. Silencing LINC02532 delayed tumor growth in mice. In terms of mechanism, LINC02532 mainly existed in the cytoplasm and could mediate HMGA1 expression by absorbing miR-541-3p. The findings offer new insights into the molecular mechanisms of LINC02532 in BCa and, more importantly, new strategies for the clinical treatment of BCa.

Epigenetic programing of cancer stemness by transcription factors-non-coding RNAs interactions

Cancer 'stemness' is fundamental to cancer existence. It defines the ability of cancer cells to indefinitely perpetuate as well as differentiate. Cancer stem cell populations within a growing tumor also help evade the inhibitory effects of chemo- as well as radiation-therapies, in addition to playing an important role in cancer metastases. NF-κB and STAT-3 are representative transcription factors (TFs) that have long been associated with cancer stemness, thus presenting as attractive targets for cancer therapy. The growing interest in non-coding RNAs (ncRNAs) in the recent years has provided further insight into the mechanisms by which TFs influence cancer stem cell characteristics. There is evidence for a direct regulation of TFs by ncRNAs, such as, microRNAs (miRNAs), long non-coding RNAs (lncRNAs) as well as circular RNAs (circRNAs), and vice versa. Additionally, the TF-ncRNAs regulations are often indirect, involving ncRNA-target genes or the sponging of other ncRNA species by individual ncRNAs. The information is rapidly evolving and this review provides a comprehensive review of TF-ncRNAs interactions with implications on cancer stemness and in response to therapies. Such knowledge will help uncover the many levels of tight regulations that control cancer stemness, providing novel opportunities and targets for therapy in the process.

Inside the stemness engine: Mechanistic links between deregulated transcription factors and stemness in cancer

Cell identity is largely determined by its transcriptional profile. In tumour, deregulation of transcription factor expression and/or activity enables cancer cell to acquire a stem-like state characterised by capacity to self-renew, differentiate and form tumours in vivo. These stem-like cancer cells are highly metastatic and therapy resistant, thus warranting a more complete understanding of the molecular mechanisms downstream of the transcription factors that mediate the establishment of stemness state. Here, we review recent research findings that provide a mechanistic link between the commonly deregulated transcription factors and stemness in cancer. In particular, we describe the role of master transcription factors (SOX, OCT4, NANOG, KLF, BRACHYURY, SALL, HOX, FOX and RUNX), signalling-regulated transcription factors (SMAD, β-catenin, YAP, TAZ, AP-1, NOTCH, STAT, GLI, ETS and NF-κB) and unclassified transcription factors (c-MYC, HIF, EMT transcription factors and P53) across diverse tumour types, thereby yielding a comprehensive overview identifying shared downstream targets, highlighting unique mechanisms and discussing complexities.

LncRNA HLA-F-AS1 attenuates the ovarian cancer development by targeting miR-21-3p/PEG3 axis

Dysregulated long noncoding RNA (lncRNA) HLA-F-AS1 is depicted in numerous cancers. However, its function in ovarian cancer has yet to be clarified. LncRNA HLA-F-AS1, miR-21-3p, and PEG3 expressions in ovarian cancer tissues and cells were measured via reverse transcription quantitative PCR. Scratch and CCK8 assays were performed to evaluate the cells' migratory and proliferative abilities, respectively. To assess the expressions of the apoptosis-related proteins Bax and Bcl-2, Western blotting was conducted. Anti-AGO2 RNA immunoprecipitation (RIP) and dual-luciferase reporter assays were executed to study lncRNA HLA-F-AS1's and PEG3 3'UTR's interactions to miR-21-3p. Finally, the tumor growth in vivo was inspected by performing a xenograft experiment. Among the ovarian cancer tissues and cells, the expressions of PEG3 and lncRNA HLA-F-AS1 were depleted while an elevated miR-21-3p expression was observed. HLA-F-AS1's overexpression attenuated ovarian cancer development in vivo and in vitro . MiR-21-3p targeted PEG3 3'UTR while HLA-F-AS1 targeted miR-21-3p. HLA-F-AS1 overexpression mitigated the enhancement brought about by miR-21-3p mimic on ovarian cancer cells' proliferation and migration. Meanwhile, PEG3 overexpression abrogated miR-21-3p mimic's function as an oncogene in the progression of ovarian cancer. Ovarian cancer development is suppressed when lncRNA HLA-F-AS1 targets the miR-21-3p/PEG3 axis. This may possibly be a novel therapeutic target for ovarian cancer.

Long non-coding RNA HLA-F antisense RNA 1 inhibits the maturation of microRNA-613 in polycystic ovary syndrome to promote ovarian granulosa cell proliferation and inhibit cell apoptosis

MicroRNA-613 (miR-613) inhibits granulosa cell proliferation, suggesting its involvement in polycystic ovary syndrome (PCOS). We predicted that long non-coding RNA (lncRNA) HLA-F antisense RNA 1 (HLA-F-AS1) could interact with premature miR-613. We then explored the crosstalk between HLA-F-AS1 and miR-613 in PCOS. In this study, follicular fluid donated by 58 healthy controls and 58 PCOS patients was used to analyze the expression of HLA-F-AS1 and miR-613 (mature and premature). The direct interaction between HLA-F-AS1 and premature miR-613 was evaluated by RNA pull-down assay. Overexpression of both HLA-F-AS1 and miR-613 was achieved in granulosa cells to assess their interactions. Cell proliferation and apoptosis were detected with BrdU assay and cell apoptosis assay, respectively. We found that miR-613 was highly expressed in PCOS, while HLA-F-AS1 was downregulated in PCOS. HLA-F-AS1 directly interacted with premature miR-613, and overexpression of HLA-F-AS1 increased the expression levels of premature miR-613, but decreased the expression levels of mature miR-613. HLA-F-AS1 increased ovarian granulosa cell proliferation and inhibited cell apoptosis. MiR-613 played an opposite role and suppressed the role of HLA-F-AS1. Therefore, HLA-F-AS1 may inhibit the maturation of miR-613 in PCOS to promote ovarian granulosa cell proliferation and inhibit cell apoptosis.

LncRNA HLA-F-AS1 Enhances the Migration, Invasion and Apoptosis of Glioblastoma Cells by Targeting lncRNA MEG3

Background

Previous studies revealed the oncogenic role of long non-coding RNA (lncRNA) HLA-F-AS1 in colon cancer and breast cancer, while its role in other cancers is unclear. We predicted the direct interaction between HLA-F-AS1 and MEG3, which is a tumor suppressor lncRNA. We then assessed the interaction between HLA-F-AS1 and MEG3 in glioblastoma (GBM).

Methods

The expression levels of HLA-F-AS1 and MEG3 in GBM and paired non-tumor tissues from 60 GBM patients were analyzed by RT-qPCR. Overexpression of HLA-F-AS1 and MEG3 was achieved in GBM cells to explore the interaction between them. The direct interaction between them was confirmed by RNA pull-down assay. The roles of HLA-F-AS1 and MEG3 in cell invasion, migration and apoptosis were explored by Transwell assays and cell apoptosis assay.

Results

HLA-F-AS1 was highly expressed, and MEG3 was downregulated in GBM. Overexpression of HLA-F-AS1 reduced the expression levels of MEG3 while overexpression of MEG3 did not alter the expression of HLA-F-AS1. HLA-F-AS1 increased cell migration and invasion, but decreased cell apoptosis. MEG3 played opposite roles and reduced the effects of HLA-F-AS1 on cell behaviors.

Conclusion

HLA-F-AS1 may sponge MEG3 in GBM cells to promote cell invasion and migration, and to suppress cell apoptosis.

Dynamic m6A-ncRNAs association and their impact on cancer pathogenesis, immune regulation and therapeutic response

Several types of modifications have been proven to participate in the metabolism and processing of different RNA types, including non-coding RNAs (ncRNAs). N-6-methyladenosine (m6A) is a dynamic and reversible RNA modification that is closely involved in the ncRNA homeostasis, and serves as a crucial regulator for multiple cancer-associated signaling pathways. The ncRNAs usually regulate the epigenetic modification, mRNA transcription and other biological processes, displaying enormous roles in human cancers. In this review, we summarized the significant implications of m6A-ncRNA interaction in various types of cancers. In particular, the interplay between m6A and ncRNAs in cancer pathogenesis and therapeutic resistance are being widely recognized. We also discussed the relevance of m6A-ncRNA interaction in immune regulation, followed by the interference on cancer immunotherapeutic procedures. In addition, we briefly highlighted the computation tools that could identify the accurate features of m6A methylome among ncRNAs. In summary, this review would pave the way for a better understanding of the biological functions of m6A-ncRNA crosstalk in cancer research and treatment.

Identifying an lncRNA-Related ceRNA Network to Reveal Novel Targets for a Cutaneous Squamous Cell Carcinoma

Simple Summary

The exact functions and molecular mechanism of lncRNAs, acting as competitive endogenous RNAs in a cutaneous squamous cell carcinoma, remain unexplored. The present study was conducted to identify the differentially expressed lncRNAs and mRNAs and establish the lncRNA-related competing endogenous RNA networks associated with a cutaneous squamous cell carcinoma. A competing endogenous RNA network consisting of 137 miRNA-lncRNA and 221 miRNA-mRNA pairs was constructed. As for the functional analysis of the mRNAs in the network, a FoxO signaling pathway, an autophagy and cellular senescence were the top enrichment terms based on the Kyoto Encyclopedia of Genes and Genomes analysis. We identified five core mRNAs and built a core mRNA-associated competing endogenous RNA network. Finally, one lncRNA HLA-F-AS1 and three mRNAs named AGO4, E2F1 and CCND1 in the core mRNA-associated competing endogenous RNA network were validated with the same expression patterns. The core mRNAs and their associated lncRNAs may provide potential therapeutic targets for cutaneous squamous cell carcinomas.

Abstract

A cutaneous squamous cell carcinoma (cSCC) derived from keratinocytes is the second most common cause of non-melanoma skin cancer. The accumulation of the mutational burden of genes and cellular DNA damage caused by the risk factors (e.g., exposure to ultraviolet radiation) contribute to the aberrant proliferation of keratinocytes and the formation of a cSCC. A cSCC encompasses a spectrum of diseases that range from recursor actinic keratosis (AK) and squamous cell carcinoma (SCC) in situ (SCCIS) to invasive cSCCs and further metastatic SCCs. Emerging evidence has revealed that lncRNAs are involved in the biological process of a cSCC. According to the ceRNA regulatory theory, lncRNAs act as natural miRNA sponges and interact with miRNA response elements, thereby regulating the mRNA expression of their down-stream targets. This study was designed to search for the potential lncRNAs that may become potential therapeutic targets or biomarkers of a cSCC. Considering the spirit of the study to be adequately justified, we collected microarray-based datasets of 19 cSCC tissues and 12 normal skin samples from the GEO database (GSE42677 and GSE45164). After screening the differentially expressed genes via a limma package, we identified 24 differentially expressed lncRNAs (DElncRNAs) and 3221 differentially expressed mRNAs (DEmRNAs). The miRcode, miRTarBase, miRDB and TargetScan databases were used to predict miRNAs that could interact with DElncRNAs and DEmRNAs. A total of 137 miRNA-lncRNA and 221 miRNA-mRNA pairs were retained in the ceRNA network, consisting of 31 miRNAs, 11 DElncRNAs and 155 DEmRNAs. For the functional analysis, the top enriched biological process was enhancer sequence-specific DNA binding in Gene Ontology (GO) terms. The FoxO signaling pathway, autophagy and cellular senescence were the top enrichment terms based on a Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. The combination of a STRING tool and Cytoscape software (plug-in MCODE) identified five core mRNAs and built a core mRNA-associated ceRNA network. The expression for five identified core mRNAs and their related nine lncRNAs was validated using the external dataset GSE7553. Finally, one lncRNA HLA-F-AS1 and three mRNAs named AGO4, E2F1 and CCND1 were validated with the same expression patterns. We speculate that lncRNA HLA-F-AS1 may sponge miR-17-5p or miR-20b-5p to regulate the expression of CCND1 and E2F1 in the cSCC. The present study may provide potential diagnostic and therapeutic targets for cSCC patients.