Long non-coding RNA DSCAM-AS1 contributes to the tumorigenesis of cervical cancer by targeting miR-877-5p/ATXN7L3 axis

METTL3-modified lncRNA DSCAM-AS1 promotes breast cancer progression through inhibiting ferroptosis

Numerous studies have indicated that N6-methyladenosine (m6A) and lncRNAs play pivotal roles in human cancer. However, the underlying functions and mechanisms of m6A-lncRNA in the physiological processes of breast cancer remain unclear. Here, we found that DSCAM-AS1 is an m6A-modified lncRNA that was overexpressed in breast cancer tissues and cells, indicating poor clinical prognosis. Gain/loss functional assays suggested that DSCAM-AS1 inhibited erastin-induced ferroptosis in breast cancer cells. Mechanistically, there were remarkable m6A modification sites on both the 3'-UTR of DSCAM-AS1 and the endogenous antioxidant factor SLC7A11. M6A methyltransferase methyltransferase-like 3 (METTL3) methylated both SLC7A11 and DSCAM-AS1. Moreover, DSCAM-AS1 recognized m6A sites on the SLC7A11 mRNA, thereby enhancing its stability. Taken together, these findings indicated a potential therapeutic strategy for breast cancer ferroptosis in an m6A-dependent manner.

circ_0039787 promotes cervical cancer cell tumorigenesis by regulation of the miR-877-5p-KRAS axis

Circular RNA (circRNA) is a novel type of RNA that plays an important role in the occurrence and development of many malignant tumors. However, the potential regulatory role and molecular mechanisms of circRNAs in cervical cancer (CC) are still not clear. Here, we explored circRNAs associated with CC from the Gene Expression Omnibus (GEO) datasets GSE113696 and GSE102686. We initially identified circ_0039787, which is derived from exons 2 to 3 of the C16orf70 gene. We observed that circ_0039787 is mainly located in the cytoplasm and is more stable than its linear counterpart, C16orf70. circ_0039787 is significantly upregulated in CC tissues and cells. In addition, functional gain and loss experiments demonstrated that circ_0039787 promotes the proliferation, migration, and invasion of CC cells in vitro and the growth of CC tumors in vivo. Mechanistically, circ_0039787 promotes CC tumor progression by competitively absorbing miR-877-5p to alleviate the inhibitory effect of miR-877-5p on Kirsten Rat Sarcoma viral oncogene homolog (KRAS) expression. Overall, our results suggest that circ_0039787 could serve as a promising diagnostic biomarker and potential therapeutic target for CC patients.

Identifying Stress-Exacerbated Thermal-Injury Induced MicroRNAs

Using a model of combat and operational stress reaction (COSR), our lab recently showed that exposure to an unpredictable combat stress (UPCS) procedure prior to a thermal injury increases pain sensitivity in male rats. Additionally, our lab has recently shown that circulating extracellular vesicle-microRNAs (EV-miRNAs), which normally function to suppress inflammation, were downregulated in a male rat model of neuropathic pain. In this current study, male and female rats exposed to UPCS, followed by thermal injury, were evaluated for changes in circulating EV-miRNAs. Adult female and male Sprague Dawley rats were exposed to a UPCS procedure for either 2 or 4 weeks. Groups consisted of the following: nonstress (NS), stress (S), NS + thermal injury (TI), and S + TI. Mechanical sensitivity was measured, and plasma was collected at baseline, throughout the UPCS exposure, and post-thermal injury. EV-miRNA isolation was performed, followed by small RNA sequencing and subsequent data analysis. UPCS exposure alone resulted in mechanical allodynia in both male and female rats at specific time points. Thermal-injury induction occurring at peak UPCS resulted in increased mechanical allodynia in the injured hind paw compared to thermal injury alone. Differential expression of the EV-miRNAs was observed between the NS and S groups as well as between NS + TI and S + TI groups. Consistent differences in EV-miRNAs are detectable in both COSR as well as during the development of mechanical sensitivity and potentially serve as key regulators, biomarkers, and targets in the treatment of COSR and thermal-injury induced mechanical sensitivity. PERSPECTIVE: This article presents the effects of unpredictable combat stress and thermal injury on EV-contained microRNAs in an animal model. These same mechanisms may exist in clinical patients and could be future prognostic and diagnostic biomarkers.

A Comprehensive Study on Signal Transduction and Therapeutic Role of miR-877 in Human Cancers

MicroRNAs are a group of short non-coding RNAs (miRNAs), which are epigenetically involved in gene expression and other cellular biological processes and can be considered as potential biomarkers for cancer detection and support for treatment management. This review aims to amass the evidence in order to reach the molecular mechanism and clinical significance of miR-877 in different types of cancer. Dysregulation of miR-877 level in various types of malignancies as bladder cancer, cervical cancer, cholangiocarcinoma, colorectal cancer (CRC), gastric cancer, glioblastoma, head and neck squamous cell carcinoma (HNSCC), hepatocellular carcinoma, laryngeal squamous cell carcinoma, melanoma, non-small cell lung cancer (NSCLC), oral squamous cell carcinoma, ovarian cancer (OC), pancreatic ductal adenocarcinoma, and renal cell carcinoma (RCC) have reported, significantly increase or decrease in its level, which can be indicated to its function as oncogene or tumor suppressor. MiR-877 is involved in cell proliferation, migration, and invasion through cell cycle pathways in cancer. MiR-877 could be potential a candidate as a valuable biomarker for prognosis in various cancers. Through this study, we proposed that miR-877 can potentially be a candidate as a prognostic marker for early detection of tumor development, progression, as well as metastasis.

METTL3-Mediated N6-Methyladenosine Modification of lncRNA D26496 Suppresses the Proliferation and Migration of Schwann Cells after Sciatic Nerve Injury

Previous reports showed that LncRNA D26496 was downregulated and N6-methyladenosine (m6A) methyltransferase METTL3 was upregulated in sciatic nerve injury (SNI). YTH-Domain Family Member 2 (YTHDF2) regulated RNA degradation through recognizing m6A sites. However, whether METTL3-mediated m6A of D26496 plays a role in development of SNI is unknown. Therefore, in this study, we established a rat SNI model and a H₂O₂-induced Schwann cell injury model to investigate the role of D26496 in modulating SNI and how the expression of D26496 was regulated during this process. D26496 expression was downregulated in both models. Rats with SNI displayed severe oxidative stress, manifested as increased MDA production and decreased SOD and GSH activity. Moreover, overexpression of D26496 alleviated H₂O₂-induced Schwann cell injury likely by promoting cell proliferation and migration and suppressing cell apoptosis and oxidative stress. Mechanism studies found that METTL3 expression was upregulated after SNI, and silencing METTL3 reduced the D26496 m6A level, but upregulated D26496 expression. Subsequent studies found that YTHDF2 was upregulated after SNI, and abundant m6A modified D26496 in the precipitated protein-RNA complexes by anti-YTHDF2 antibody, whereas silencing YTHDF2 promoted D26496 expression but had no effect on m6A levels of D29496. Silencing D26496 reversed the protective effect of knocking down METTL3 or knocking down YTHDF2 on H₂O₂-induced cell damage. In vivo, D26496 overexpression alleviated SNI-induced neuropathic pain and oxidative stress. In conclusion, our results suggested that D26496 m6A modification mediated by METTL3 and recognition of D26496 m6A sites by YTHDF2 induced D26496 degradation, thereby participating in the progression of SNI.

Advances in epigenetic modifications and cervical cancer research

Cervical cancer (CC) is an important public health problem for women, and perspectives and information regarding its prevention and treatment are quickly evolving. Human papilloma virus (HPV) has been recognized as a major contributor to CC development; however, HPV infection is not the only cause of CC. Epigenetics refers to changes in gene expression levels caused by non-gene sequence changes. Growing evidence suggests that the disruption of gene expression patterns which were governed by epigenetic modifications can result in cancer, autoimmune diseases, and various other maladies. This article mainly reviews the current research status of epigenetic modifications in CC based on four aspects, respectively DNA methylation, histone modification, noncoding RNA regulation and chromatin regulation, and we also discuss their functions and molecular mechanisms in the occurrence and progression of CC. This review provides new ideas for early screening, risk assessment, molecular targeted therapy and prognostic prediction of CC.

Long non‑coding RNA DSCAM‑AS1 functions as an oncogene in thyroid cancer via regulating miR‑211

Long non-coding RNA Down syndrome cell adhesion molecule-antisense 1 (DSCAM-AS1) has been reported to play key roles in the progression and initiation of several cancer types. However, the various functional roles of DSCAM-AS1 in thyroid cancer tumorigenesis remain largely elusive. In the present study, the expression of DSCAM-AS1 was examined in thyroid cancer tissues and cell lines. Cell Counting Kit-8, wound healing, Transwell and clonogenic assays were conducted to detect cell proliferation, migration, invasion and colony formation, respectively. The association of DSCAM-AS1 with microRNA 211 (miR-211) was determined by luciferase reporter assay. It was found that the expression of DSCAM-AS1 was upregulated in thyroid cancer cells and tissues. Furthermore, enhanced DSCAM-AS1 expression was positively associated with lymph node metastasis and tumor-node-metastasis stage. Functional experiments demonstrated that DSCAM-AS1 knockdown inhibited the migration, proliferation and invasion of TPC-1 cells. Mechanistically, DSCAM-AS1 could bind to miR-211. Prevention of miR-211 by a miR-211 inhibitor reversed the effect of DSCAM-AS1 depletion in thyroid cancer tumorigenesis. Briefly, the current findings suggested that knockdown of DSCAM-AS1 suppressed the tumorigenesis of thyroid cancer via regulating miR-211, suggesting that DSCAM-AS1 may be a favorable therapeutic target for thyroid cancer.

CircCOL5A1 inhibits proliferation, migration, invasion, and extracellular matrix production of keloid fibroblasts by regulating the miR-877-5p/EGR1 axis

BACKGROUND

Circular RNA (circRNA) has been proved to mediate the biological functions of fibroblasts to participate in the regulation of keloid formation. However, the role of circCOL5A1 in keloid formation remains to be further confirmed.

METHODS

Primary keloid fibroblasts were isolated form keloid tissues. The expression of circCOL5A1, microRNA (miR)- 877-5p, and early growth response 1 (EGR1) were determined by quantitative real-time PCR. Transfection experiments were carried out to explore the effects of circCOL5A1, miR-877-5p, and EGR1 on cell functions. Cell proliferation, migration, invasion and apoptosis were detected using cell counting kit 8 assay, colony formation assay, transwell assay and flow cytometry. The protein levels of apoptosis markers, extracellular matrix (ECM) markers and EGR1 were measured by western blot analysis. The mechanism of circCOL5A1 was confirmed by RNA pull-down assay, dual-luciferase reporter assay and RIP assay.

RESULTS

Our data showed that circCOL5A1 was upregulated in keloid tissues and fibroblasts. Silencing of circCOL5A1 had an inhibition effect on proliferation, migration, invasion and ECM production, while had a promotion effect on apoptosis in keloid fibroblasts. MiR-877-5p could be sponged by circCOL5A1, and its overexpression could repress the biological functions of keloid fibroblasts. The rescue experiments showed that miR-877-5p inhibitor could reverse the suppressive effect of circCOL5A1 knockdown on the biological functions of keloid fibroblasts. In addition, EGR1 was a target of miR-877-5p, and its expression was positively regulated by circCOL5A1. The inhibition effect of miR-877-5p on the biological functions of keloid fibroblasts could be abolished by EGR1 overexpression.

CONCLUSION

In summary, circCOL5A1 facilitates keloid fibroblast proliferation, migration, invasion and ECM production through the miR-877-5p/EGR1 axis, thereby potentially promoting keloid formation.

Long Noncoding RNA DSCAM-AS1 Facilitates Proliferation and Migration of Hemangioma Endothelial Cells by Targeting miR-411-5p/TPD52 Axis

Background

Diagnosed as a kind of vascular neoplasm of infancy, hemangioma (HA) occurs mainly due to the aberrant proliferation of endothelial cells. Existing evidence has manifested the close relationship of long noncoding RNAs (lncRNAs) with the pathogenesis of HA. Although lncRNA DSCAM antisense RNA 1 (DSCAM-AS1) has been revealed to be implicated in the progression of human diseases, the underlying mechanism DSCAM-AS1 exerts in HA formation is unclear.

Aims

To figure out how DSCAM-AS1 may regulate the progression of human hemangioma endothelial cells (HemECs).

Methods

DSCAM-AS1 expression was verified through RT-qPCR detection. Functional assays including EdU assay, colony formation assay, flow cytometry analysis, TUNEL assay, and transwell assay were applied to evaluate cell proliferation, apoptosis, and migration upon DSCAM-AS1 knockdown. Moreover, RNA pull-down assay, luciferase reporter assay, RIP assay, and other mechanism experiments were utilized for evaluating the correlation of DSCAM-AS1 and RNAs in HemECs.

Results

DSCAM-AS1 knockdown inhibited proliferative capability and migratory capability of HemECs whereas expedited apoptosis. Molecular mechanism results testified DSCAM-AS1 could function as a ceRNA to bind miR-411-5p in HemECs. Besides, it was confirmed that tumor protein D52 (TPD52) served as a downstream target of miR-411-5p in HemECs. More importantly, related rescue assays uncovered that elevated expression of TPD52 or inhibited expression of miR-411-5p reversed the repressive progression of HemECs mediated by DSCAM-AS1 depletion.

Conclusion

DSCAM-AS1 expedited HA progression via miR-411-5p/TPD52 pathway, which provided a novel therapeutic option for HA treatment.

DSCAM-AS1 Long Non-Coding RNA Exerts Oncogenic Functions in Endometrial Adenocarcinoma via Activation of a Tumor-Promoting Transcriptome Profile

Accumulating evidence suggests that lncRNA DSCAM-AS1 acts tumor-promoting in various cancer entities. In breast cancer, DSCAM-AS1 was shown to be the lncRNA being most responsive to induction by estrogen receptor α (ERα). In this study, we examined the function of DSCAM-AS1 in endometrial adenocarcinoma using in silico and different in vitro approaches. Initial analysis of open-source data revealed DSCAM-AS1 overexpression in endometrial cancer (EC) (p < 0.01) and a significant association with shorter overall survival of EC patients (HR = 1.78, p < 0.01). In EC, DSCAM-AS1 was associated with endometrial tumor promotor gene PRL and with expression of ERα and its target genes TFF1 and PGR. Silencing of this lncRNA by RNAi in two EC cell lines was more efficient in ERα-negative HEC-1B cells and reduced their growth and the expression of proliferation activators like NOTCH1, PTK2 and EGR1. DSCAM-AS1 knockdown triggered an anti-tumoral transcriptome response as revealed by Affymetrix microarray analysis, emerging from down-regulation of tumor-promoting genes and induction of tumor-suppressive networks. Finally, several genes regulated upon DSCAM-AS1 silencing in vitro were found to be inversely correlated with this lncRNA in EC tissues. This study clearly suggests an oncogenic function of DSCAM-AS1 in endometrial adenocarcinoma via activation of a tumor-promoting transcriptome profile.

MicroRNA-877-5p Inhibits Cell Progression by Targeting FOXM1 in Lung Cancer

Background

Many researches revealed that microRNAs (miRNAs) function as potential oncogene or tumor suppressor gene. As an antioncogene, miR-877-5p was reduced in many tumors.

Objective

This research aimed to explore the biological role and mechanisms of miR-877-5p, which may help patients with non-small-cell lung cancer (NSCLC) find effective therapeutic targets.

Methods

The downstream targets of miR-877-5p were predicted by Bioinformatics software. RT-qPCR and western blot were employed to analyze the gene levels. The impacts of miR-877-5p and FOXM1 were assessed by cell function experiments.

Results

The miR-877-5p was reduced in NSCLC. In addition to this, it also inhibited cell progression of NSCLC cells in vitro. Moreover, the upregulation of FOXM1 expression restored the inhibitory effect of enhancement of miR-877-5p.

Conclusions

Taken together, miR-877-5p inhibited cell progression by directly targeting FOXM1, which may provide potential biomarkers for targeted therapy of NSCLC.

MicroRNA-17-5p Protects against Propofol Anesthesia-Induced Neurotoxicity and Autophagy Impairment via Targeting BCL2L11

Background. Propofol (PPF) has been shown in studies to cause cognitive impairment and neuronal cell death in developing animals. PPF has been demonstrated to decrease the expression of microRNA-17-5p (miR-17-5p) in a recent study. Nonetheless, the function of miR-17-5p in PPF-induced neurotoxicity and related mechanisms is uncharacterized. Methods. After the induction of neurotoxicity by treating the SH-SY5Y cells with PPF, qRT-PCR was conducted to evaluate the level of miR-17-5p. Using MTT and flow cytometry, cell viability and apoptosis rate were assessed, respectively. Interaction between miR-17-5p and BCL2 like 11 was (BCL2L11) studied using a Luciferase reporter assay. With the help of western blot analysis, we determined the level of proteins of apoptosis-related genes and autophagy-related markers. Results. In SH-SY5Y cells, PPF treatment induced neurotoxicity and downregulated miR-17-5p expression. In SH-SY5Y cells post-PPF exposure, overexpression of miR-17-5p increased cell viability and decreased apoptosis. Consistently, miR-17-5p mimics mitigated PPF-generated autophagy via inhibition of Atg5, Beclin1, and LC3II/I level and elevation of p62 protein expression. In addition, BCL2L11, which was highly expressed in PPF-treated SH-SY5Y cells, was directly targeted by miR-17-5p. Further, in PPF-treated SH-SY5Y cells, overexpressed BCL2L11 counteracted the suppressing behavior of miR-17-5p elevation on PPF-induced apoptosis. Conclusion. Overexpressed miR-17-5p alleviates PPF exposure-induced neurotoxicity and autophagy in SH-SY5Y cells via binding to BCL2L11, suggesting the possibility that miR-17-5p can serve as a candidate in the treatment of neurotoxicity (caused by PPF).

Long non-coding RNA DSCAM-AS1 promotes pancreatic cancer progression via regulating the miR-136-5p/PBX3 axis

LncRNA down syndrome cell adhesion molecule antisense 1 (DSCAM-AS1) plays an important role in tumor progression, but its function in pancreatic cancer is unknown. DSCAM-AS1 level was evaluated by in situ hybridization (ISH) assay and qRT-PCR. DSCAM-AS1 was knocked down in pancreatic cancer cells, and its impacts on cell proliferation, invasion, and migration were detected. The binding relationship among DSCAM-AS1, miR-136-5p, and pre-B-cell leukemia homeobox 3 (PBX3) was investigated by bioinformatic analysis and luciferase reporter assay. An in vivo animal model was constructed to determine the role of DSCAM-AS1 in tumor growth. Our results showed that DSCAM-AS1 was elevated in tumor tissues of pancreatic cancer patients and cell lines. DSCAM-AS1 knockdown efficiently inhibited PANC-1 cell proliferation, migration, and invasion and suppressed tumor growth. DSCAM-AS1 could promote PBX3 expression by sponging miR-136-5p, and its function in pancreatic cancer was partially mediated by the miR-136-5p/PBX3 axis. Overall, DSCAM-AS1 knockdown inhibits pancreatic cancer progression by modulating the miR-136-5p/PBX3 axis.

CircRNA PRH1-PRR4 stimulates RAB3D to regulate the malignant progression of NSCLC by sponging miR-877-5p

BACKGROUND

Previous reports have confirmed the importance of circular RNA (circRNA) in the malignant progression of non-small-cell lung cancer (NSCLC). However, the role of circRNA PRH1-PRR4 readthrough (circPRH1-PRR4) in NSCLC progression was unclear. This study was designed to reveal the mechanism behind circPRH1-PRR4 regulating NSCLC progression.

METHODS

Quantitative real-time polymerase chain reaction and western blot were employed to detect the expression of circPRH1-PRR4, microRNA-877-5p (miR-877-5p), the member RAS oncogene family (RAB3D), and other indicated protein markers. The positive expression rate of RAB3D was detected by immunohistochemistry assay. Cell proliferation was investigated by cell colony formation and 5-ethynyl-2'-deoxyuridine assays. Flow cytometry was employed to quantify apoptotic cells. Wound-healing and transwell invasion assays were used to evaluate cell metastasis. The interaction among circPRH1-PRR4, miR-877-5p, and RAB3D was identified by dual-luciferase reporter assay. In vivo assay was implemented to demonstrate the effect of circPRH1-PRR4 on tumor formation.

RESULTS

As compared with controls, NSCLC tissues and cells displayed high expression of circPRH1-PRR4 and RAB3D, and low expression of miR-877-5p. Reduced expression of circPRH1-PRR4 resulted in inhibition of cell proliferation, migration, and invasion, but promotion of cell apoptosis in vitro. In support, circPRH1-PRR4 silencing inhibited tumor formation in vivo. Knockdown of miR-877-5p, a target miRNA of circPRH1-PRR4, relieved circPRH1-PRR4 absence-mediated action. Additionally, RAB3D was identified as a target mRNA of miR-877-5p. Importantly, circPRH1-PRR4 regulated RAB3D expression by miR-877-5p.

CONCLUSION

CircPRH1-PRR4 knockdown impeded NSCLC cell malignancy by the miR-877-5p/RAB3D pathway, providing a possible circRNA-targeted therapy for NSCLC.

LncRNA MAGI2-As3 Suppresses the Proliferation and Invasion of Cervical Cancer by Sponging MiR-15b

BACKGROUND

Cervical cancer is the leading cause of cancer deaths among women, and more than 85% of cervical cancer deaths occur in low and middle-income countries. The purpose of this study is to investigate the functions of MAGI2-AS3 and miR-15b in cervical cancer.

MATERIALS AND METHODS

The mRNA levels of MAGI2-AS3, miR-15b, and CCNE1 were evaluated using RT-qPCR assay. Dual-luciferase reporter gene assay was used to confirm whether miR-15b binds to CCNE1.

RESULTS

LncRNA MAGI2-AS3 was downregulated, while miR-15b was upregulated in cervical cancer. Cervical cancer patients with low expression of MAGI2-AS3 have a poor prognosis. Upregulation of MAGI2-AS3 inhibited proliferative and invasive abilities of HeLa cells via regulating the expression of miRNA-15b. MiR-15b inhibitor suppressed cell proliferation and invasion. CCNE1 was a direct target gene of miR-15b, which binds to the 3'-UTR of its mRNA. MiR-15b partially reversed the inhibitory effect of overexpression of MAGI2-AS3 on the proliferation and invasion of HeLa cells. MAGI2-AS3 mediated the expression of CCNE1 in HeLa cells.

CONCLUSION

LncRNA MAGI2-AS3 inhibits the proliferation and invasion of cervical cancer cells via the miRNA-15/CCNE1 axis. Our results illustrates that MAGI2-AS3 can be used as a useful clinical predictor for early diagnosis and prognosis assessment of cervical cancer.

Long Noncoding RNA Mediated Regulation in Human Embryogenesis, Pluripotency, and Reproduction

Long noncoding RNAs (lncRNAs), a class of noncoding RNAs with more than 200 bp in length, are produced by pervasive transcription in mammalian genomes and regulate gene expression through various action mechanisms. Accumulating data indicate that lncRNAs mediate essential biological functions in human development, including early embryogenesis, induction of pluripotency, and germ cell development. Comprehensive analysis of sequencing data highlights that lncRNAs are expressed in a stage-specific and human/primate-specific pattern during early human development. They contribute to cell fate determination through interacting with almost all classes of cellular biomolecules, including proteins, DNA, mRNAs, and microRNAs. Furthermore, the expression of a few of lncRNAs is highly associated with the pathogenesis and progression of many reproductive diseases, suggesting that they could serve as candidate biomarkers for diagnosis or novel targets for treatment. Here, we review research on lncRNAs and their roles in embryogenesis, pluripotency, and reproduction. We aim to identify the underlying molecular mechanisms essential for human development and provide novel insight into the causes and treatments of human reproductive diseases.

CircPIK3C2A Facilitates the Progression of Glioblastoma via Targeting miR-877-5p/FOXM1 Axis

Glioblastoma is a rare yet lethal type of tumor that poses a crucible for the medical profession, owing to its rapid proliferation and invasion resulting in poor prognosis. Circular RNAs (circRNAs), a subclass of regulatory RNAs, are implicated in the regulation of cancerous progression. This study aims to investigate the roles and underlying mechanism of circPIK3C2A in regulating proliferation and invasion of glioblastoma. qRT-PCR assays showed that the expression level of circPIK3C2A was aberrantly higher in glioblastoma cell lines, in comparison with that in normal glia cells. The ectopic expression of circPIK3C2A promoted the proliferation, invasion and clonal formation of glioblastoma cells, while circPIK3C2A loss-of-function exerted exactly the opposite biological effects on the cells. The construction of subcutaneous xenograft tumor model in nude mice indicated that circPIK3C2A loss-of-function effectively diminished tumor load in vivo and prolonged the survival time of tumor-bearing animals. Luciferase reporter assay confirmed the interaction among circPIK3C2A/miR-877-5p and FOXM1. CircPIK3C2A function as competitive endogenous RNA via sponging miR-877-5p through certain binding sites, thereby modulating the expression of FOXM1. Our results collectively indicate that circPIK3C2A functions as ceRNA by mediating miR-877-5p/FOXM1 axis, providing a novel perspective of applying CircPIK3C2A in the clinical intervention of glioblastoma in the future.

Hsa_circ_0042823 accelerates cancer progression via miR-877-5p/FOXM1 axis in laryngeal squamous cell carcinoma

BACKGROUND

Laryngeal squamous cell carcinoma (LSCC) is a common malignant tumour of the head and neck. Our previous study reveals that the circular RNA (circRNA) hsa_circ_0042823 is abnormally expressed in LSCC, suggesting that hsa_circ_0042823 is closely associated with LSCC. Here, we attempted to explore the molecular mechanism of hsa_circ_0042823 in LSCC.

METHODS

Quantitative real-time PCR and western blot were performed to assess the expression of gene and protein in human laryngeal carcinoma cells, TU212 and TU686. MTT and transwell assays were performed to examine cell proliferation, migration and invasion. The relationship among hsa_circ_0042823, miR-877-5p and forkhead box M1 (FOXM1) was verified by luciferase reporter assay. Finally, we constructed a subcutaneous tumour mouse model to analyse in vivo growth of LSCC cells following knockdown of hsa_circ_0042823.

RESULTS

Compared with normal human bronchial epithelial cells (HBECs), hsa_circ_0042823 was highly expressed in the LSCC cell lines (AMC-HN-8 and TU686). Further studies demonstrated that hsa_circ_0042823 interacted with miR-877-5p, and FOXM1 was the target of miR-877-5p. Hsa_circ_0042823 promoted the expression of FOXM1 via its ceRNA activity on miR-877-5p. Hsa_circ_0042823 overexpression promoted proliferation, migration and invasion of AMC-HN-8 cells through regulating miR-877-5p/FOXM1 axis. Additionally, inhibition of hsa_circ_0042823 inhibited growth of LSCC in vivo via miR-877-5p/FOXM1 axis.

CONCLUSIONS

Hsa_circ_0042823/miR-877-5p/FOXM1 axis participates in the progression of LSCC. This work demonstrates that hsa_circ_0042823 accelerates cancer progression by regulating miR-877-5p/FOXM1 axis in LSCC. Therefore, this study may provide new insights into the pathogenesis of LSCC.KEY MESSAGESHsa_circ_0042823 promotes FOXM1 expression by sponging miR-877-5p.Hsa_circ_0042823 promotes proliferation, migration, invasion of LSCC cells.Hsa_circ_0042823 knockdown inhibits tumour growth of LSCC via miR-877-5p/FOXM1 axis.

A Review on the Carcinogenic Roles of DSCAM-AS1

Long non-coding RNAs (lncRNAs) are a group of transcripts with fundamental roles in the carcinogenesis. DSCAM Antisense RNA 1 (DSCAM−AS1) is an example of this group of transcripts which has been firstly identified in an attempt to find differentially expressed transcripts between breast tumor cells and benign breast samples. The pathogenic roles of DSCAM-AS1 have been vastly assessed in breast cancer, yet its roles are not restricted to this type of cancer. Independent studies in non-small cell lung cancer, colorectal cancer, osteosarcoma, hepatocellular carcinoma, melanoma and cervical cancer have validated participation of DSCAM-AS1 in the carcinogenic processes. miR-577, miR-122-5p, miR-204-5p, miR-136, miR−137, miR−382, miR−183, miR−99, miR-3173-5p, miR-874-3p, miR-874-3p, miR-150-5p, miR-2467-3p, miR-216b, miR-384, miR-186-5p, miR-338-3p, miR-877-5p and miR-101 are among miRNAs which interact with DSCAM-AS1. Moreover, this lncRNA has interactions with Wnt/β-catenin pathway. The current study aims at summarization of the results of studies which focused on the assessment of oncogenic role of DSCAM-AS1.

lncRNA DSCAM-AS1 facilitates the progression of endometrial cancer via miR-136-5p

Previous studies have indicated that long non-coding RNA (lncRNA) down syndrome cell adhesion molecule antisense 1 (DSCAM-AS1) serves an oncogenic role in numerous cancer types. However, its role in endometrial cancer (EC) remains largely unknown. In the present study, DSCAM-AS1 expression levels in EC tissues and cells and their normal counterparts were analyzed using reverse transcription-quantitative. In vitro and in vivo experiments were conducted to validate the functions of DSCAM-AS1 in EC. It was revealed that DSCAM-AS1 was expressed at a high level in EC tissues and cells after analyzing patient data and data obtained from The Cancer Genome Atlas. Notably, it was also revealed that high DSCAM-AS1 expression was associated with a less favorable overall survival in patients with EC. Knockdown of DSCAM-AS1 was able to suppress EC cell proliferation by upregulating cell apoptosis in vitro. Furthermore, it was revealed that DSCAM-AS1 acted as a microRNA (miR)-136-5p sponge to exert its oncogenic roles in EC. Collectively and to the best of our knowledge, the current results provided first evidence that DSCAM-AS1 stimulated EC progression by regulating miR-136-5p, which may improve the understanding of the roles of ncRNAs in EC, and may help identify novel targets for anticancer treatment.

microRNA-877-5p exerts tumor-suppressive functions in prostate cancer through repressing transcription of forkhead box M1

The study aimed to investigate the significant potential role of miR-877-5p in Prostate cancer. The expression levels of miR-877-5p and forkhead box M1 (FOXM1) mRNA were detected by qRT-PCR. The prognostic significance of miR-877-5p in prostate cancer was investigated using Kaplan Meier analysis. Then, Cell Counting Kit-8 (CCK-8) and transwell assay were used to evaluate the effects of miR-877-5p on cell biological functions. The mechanism of miR-877-5p action on prostate cancer cells was investigated by luciferase activity assay with wide-type or mutation. miR-877-5p was lowly expressed both in prostate cancer tissues and cell lines compared with corresponding normal counterparts. Further, miR-877-5p was significantly correlated with Gleason score and TNM stage. Moreover, miR-877-5p may serve as an independent prognostic predictor. In addition, FOXM1 was checked as a direct target gene of miR-877-5p, and miR-877-5p can inhibit the expression of FOXM1 to restrain the growth, migration, and invasion abilities of prostate cancer cells. Taken together, miR-877-5p may act as a suppressor in prostate cancer and reduces cancer cell proliferation, migration and invasion by targeting FOXM1. miR-877-5p may serve as the effective biomarkers and therapeutic target for treating prostate cancer patients.

NR2F1-AS1 Promotes Pancreatic Ductal Adenocarcinoma Progression Through Competing Endogenous RNA Regulatory Network Constructed by Sponging miRNA-146a-5p/miRNA-877-5p

The role of NR2F1-AS1 in pancreatic ductal adenocarcinoma (PDAC) remains unknown. Therefore, we aimed to investigate the biological mechanism of NR2F1-AS1 in PDAC. The expression of NR2F1-AS1 was measured by using microarray data and real-time PCR. The effects of NR2F1-AS1 knockdown on proliferation, cell cycle progression, invasion in vitro and tumorigenesis in vivo were investigated. The mechanism of competitive endogenous RNAs was determined from bioinformatics analyses and validated by a dual-luciferase reporter gene assay. Potential target mRNAs from TargetScan 7.2 were selected for subsequent bioinformatics analysis. Key target mRNAs were further identified by screening hub genes and coexpressed protein-coding genes (CEGs) of NR2F1-AS1. NR2F1-AS1 was highly expressed in PDAC, and the overexpression of NR2F1-AS1 was associated with overall survival and disease-free survival. The knockdown of NR2F1-AS1 impaired PDAC cell proliferation, migration, invasion and tumorigenesis. NR2F1-AS1 competitively sponged miR-146a-5p and miR-877-5p, and low expression of the two miRNAs was associated with a poor prognosis. An integrative expression and survival analysis of the hub genes and CEGs demonstrated that the NR2F1-AS1–miR-146a-5p/miR-877-5p–GALNT10/ZNF532/SLC39A1/PGK1/LCO3A1/NRP2/LPCAT2/PSMA4 and CLTC ceRNA networks were linked to the prognosis of PDAC. In conclusion, NR2F1-AS1 overexpression was significantly associated with poor prognosis. NR2F1-AS1 functions as an endogenous RNA to construct a novel ceRNA network by competitively binding to miR-146a-5p/miR-877-5p, which may contribute to PDAC pathogenesis and could represent a promising diagnostic biomarker or potential novel therapeutic target in PDAC.

miRNA-877-5p inhibits malignant progression of prostate cancer by directly targeting SSFA2

In this study, we aimed to investigate the role of miR-877-5p in the malignant phenotypes of prostate cancer (PCa) cells and its underlying mechanism. RT-qPCR analysis was performed to examine the expression of miR- 877-5p and sperm-specific antigen 2 (SSFA2) in PCa tissues and cells. Cell counting kit-8 (CCK-8) assay, 5- ethynyl-20-deoxyuridine (EdU) assay, flow cytometry, wound-healing assay, and Transwell invasion assay were performed to determine the functional roles of miR-877-5p in PCa cells. The association of miR-877-5p with SSFA2 was determined by luciferase reporter and RNA pull-down assays. In this study, we found that the expression level of miR-877-5p was decreased in PCa tissues and cells. Functionally, overexpression of miR- 877-5p exerted tumor suppressor properties in PCa cells. Mechanistically, SSFA2 was identified as a target gene of miR-877-5p, while overexpression of SSFA2 could abrogate the anti-tumor effects of miR-877-5p in PCa cells. These findings demonstrated that miR-877-5p/SSFA2 axis functioned as a potential target for PCa treatment.

Splice and Dice: Intronic microRNAs, Splicing and Cancer

Introns span only a quarter of the human genome, yet they host around 60% of all known microRNAs. Emerging evidence indicates the adaptive advantage of microRNAs residing within introns is attributed to their complex co-regulation with transcription and alternative splicing of their host genes. Intronic microRNAs are often co-expressed with their host genes, thereby providing functional synergism or antagonism that is exploited or decoupled in cancer. Additionally, intronic microRNA biogenesis and the alternative splicing of host transcript are co-regulated and intertwined. The importance of intronic microRNAs is under-recognized in relation to the pathogenesis of cancer.

Thymoquinone Suppresses the Proliferation, Migration and Invasiveness through Regulating ROS, Autophagic Flux and miR-877-5p in Human Bladder Carcinoma Cells

Bladder carcinoma is among the top 10 most frequently diagnosed cancer types in the world. As a phytochemical active metabolic, thymoquinone (TQ) is extracted from seeds of Nigella sativa, possessing various biological properties in a wide range of diseases. Moreover, the outstanding anti-cancer effect of TQ is attracting increasing attentions. In certain circumstances, moderate autophagy is regarded to facilitate the adaptation of malignant cells to different stressors. Conversely, closely linked with the mitochondrial membrane potential (MMP) loss, the upregulation of intracellular reactive oxygen species (ROS) is reported to activate the cell apoptosis in many cancer types. Furthermore, the vital effects of microRNAs in the pathological processes of cancer cells have also been confirmed by previous studies. The present research confirms that TQ restrains the viability, proliferation, migration and invasion through activating caspase-dependent apoptosis in bladder carcinoma cells, which is mediated by TQ induced ROS increase in bladder carcinoma cells. Furthermore, TQ is proved to block the fusion of autophagosomes and lysosomes, causing the accumulation of autophagosomes and subsequent cell apoptosis. In addition, TQ is also found to initiate the miR-877-5p/PD-L1 axis, which suppresses the epithelial mesenchymal transition (EMT) and invasion of bladder carcinoma cells. Taken together, TQ induces the apoptosis through upregulating ROS level and impairing autophagic flux, and inhibiting the EMT and cell invasion via activating the miR-877-5p/PD-L1 axis in bladder carcinoma cells.

The Biological Significance of Long noncoding RNAs Dysregulation and their Mechanism of Regulating Signaling Pathways in Cervical Cancer

Despite the remarkable decrease in cervical cancer incidence due to the availability of the HPV vaccine and implementation of screening programs for early detection in developed countries, this cancer remains a major health problem globally, especially in developing countries where most of the cases and mortality occur. Therefore, more understanding of molecular mechanisms of cervical cancer development might lead to the discovery of more effective diagnosis and treatment options. Research on long noncoding RNAs (lncRNAs) demonstrates the important roles of these molecules in many physiological processes and diseases, especially cancer. In the present review, we discussed the significance of lncRNAs altered expression in cervical cancer, highlighting their roles in regulating highly conserved signaling pathways, such as mitogen-activated protein kinase (MAPK), Wnt/β-catenin, Notch, and phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) pathways and their association with the progression of cervical cancer in order to bring more insight and understanding of this disease and their potential implications in cancer diagnosis and therapy.

Long non-coding RNA Down syndrome cell adhesion molecule-anti-sense 1 promotes gastric carcinoma cell proliferation and migration by regulating the miR-204/TPT1 axis

Background: Several recent studies have suggested that the long non-coding RNA (lncRNA) DSCAM-AS1 (Down syndrome cell adhesion molecule - anti-sense 1) is aberrantly expressed in many malignancies. Purpose: In this study, we aimed to explore the the role of DSCAM-AS1 in gastric carcinoma. Research Design: Expression of DSCAM-AS1 mRNA, miR-204, and TPT1 (Tumor Protein, Translationally-Controlled 1) were detected using quantitative real-time polymerase chain reaction (qRT-PCR). Proliferation and apoptosis of GC cells were determined using the CCK-8 cell counting assay and flow cytometry. The rate of cell migration and invasion was determined using a transwell assay. The relationships between DSCAM-AS1, miR-204, and TPT1 were predicted and confirmed using a dual-luciferase reporter assay. Expression of TPT1 protein was quantified by Western blot. Results: In this study, we found that DSCAM-AS1 was significantly overexpressed in GC tissues and cell lines. Functional experiments indicated that GC cells with DSCAM-AS1 silencing exhibited a dynamic reduction in proliferation and migration. We identified miR-204 as a target of DSCAM-AS1 and found that it targeted TPT1 in GC cells, which further led to decreased expression of miR-204 in GC tissues and cell lines. A rescue assay revealed that knocked-down DSCAM-AS1 hindered GC progression, which was reversed upon miR-204 downregulation or TPT1 overexpression. Conclusion: We conclude that DSCAM-AS1 is expressed as a tumor oncogene in GC progression, modulated via the miR-204/TPT1 axis. These findings indicate the potential of DSCAM-AS1 as a therapeutic target for GC prevention.

The role of HPV-induced epigenetic changes in cervical carcinogenesis (Review)

Cervical cancer is associated with infection by certain types of human papillomaviruses (HPVs), and this affects women worldwide. Despite the improvements in prevention and cure of HPV-induced cervical cancer, it remains the second most common type of cancer in women in the least developed regions of the world. Epigenetic modifications are stable long-term changes that occur in the DNA, and are part of a natural evolutionary process of necessary adaptations to the environment. They do not result in changes in the DNA sequence, but do affect gene expression and genomic stability. Epigenetic changes are important in several biological processes. The effects of the environment on gene expression can contribute to the development of numerous diseases. Epigenetic modifications may serve a critical role in cancer cells, by silencing tumor suppressor genes, activating oncogenes, and exacerbating defects in DNA repair mechanisms. Although cervical cancer is directly related to a persistent high-risk HPV infection, several epigenetic changes have been identified in both the viral DNA and the genome of the infected cells: DNA methylation, histone modification and gene silencing by non-coding RNAs, which initiate and sustain epigenetic changes. In the present review, recent advances in the role of epigenetic changes in cervical cancer are summarized.

Understanding the Molecular Mechanism of miR-877-3p Could Provide Potential Biomarkers and Therapeutic Targets in Squamous Cell Carcinoma of the Cervix

No therapeutic targets and molecular biomarkers are available in cervical cancer (CC) management. In other cancer types, micro-RNA-877-3p (miR-877-3p) has been associated with events relevant for CC development. Thus, we aimed to determine miR-877-3p role in CC. miR-877-3p levels were examined by quantitative-PCR in 117 cervical lesions and tumors. Effects on CC cell proliferation, migration, and invasion were evaluated upon anti-miR-877-3p transfection. miR-877-3p dependent molecular mechanism was comprehensively explored by proteomics, dual-luciferase reporter assay, western blot, and immunohistochemistry. Cervical tumors expressed higher miR-877-3p levels than benign lesions. miR-877-3p promoted CC cell migration and invasion, at least partly by modulating cytoskeletal protein folding through the chaperonin-containing T-complex protein 1 complex. Notably, miR-877-3p silencing synergized with paclitaxel. Interestingly, miR-877-3p downregulated the levels of an in silico-predicted target, ZNF177, whose expression and subcellular location significantly distinguished high-grade squamous intraepithelial lesions (HSILs) and squamous cell carcinomas of the cervix (SCCCs). Cytoplasmic ZNF177 was significantly associated with worse progression-free survival in SCCC. Our results suggest that: (i) miR-877-3p is a potential therapeutic target whose inhibition improves paclitaxel effects; (ii) the expression and location of its target ZNF177 could be diagnostic biomarkers between HSIL and SCCC; and (iii) cytoplasmic ZNF177 is a poor-prognosis biomarker in SCCC.

Long non-coding RNA VPS9D1-AS1 facilitates cell proliferation, migration and stemness in hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is a common cancer leading to high morbidity and mortality in worldwide. Previous studies revealed that SEC61 translocon alpha 1 subunit1 (SEC61A) can act as an oncogene in colon adenocarcinoma. However, the functions and molecular mechanism associated with HCC progression remain to be explored. This study aimed at exploring the role of SEC61A1 in HCC progression.

METHODS

EdU assay and colony formation assay were applied to assess cell proliferation. The migratory ability of transfected HCC cells was evaluated by transwell migration assay. Sphere formation assay was used to detect the stemneess of HCC cells. Bioinformatics analysis tools and mechanism experiments were used to predict and analyze the potential molecular mechanism associated with the upregulation of SEC61A1 in HCC cells.

RESULTS

Up-regulated SEC61A1 facilitated cell proliferation, migration and stemness in HCC cells. MiR-491-5p negatively regulated SEC61A1 and inhibited HCC cell proliferation and migration by targeting SEC61A1. VPS9D1 antisense RNA 1 (VPS9D1-AS1) could up-regulate SEC61A1 through sponging miR-491-5p. Early growth response 1 (EGR1) was identified as the upstream transcriptional activator for both SEC61A1 and VPS9D1-AS1.

CONCLUSIONS

Our study unveiled a novel molecular pathway facilitating HCC cell proliferation, migration and stemness, which may shed new insight into HCC treatment.

Long non-coding RNA (lncRNA) DSCAM-AS1 is upregulated in breast cancer

BACKGROUND

Accumulating evidence highlights that long noncoding RNA (lncRNA) DSCAM-AS1 play a key regulatory role in different stages of cancer development and progression. This study aimed to investigate whether the expression of DSCAM-AS1 is deregulated in breast cancer.

MATERIALS AND METHODS

The relative expression of DSCAM-AS1 was measured in fifty breast cancerous and matched adjacent non-neoplastic tissue samples using quantitative real-time polymerase chain reaction (qPCR) technique. The association between DSCAM-AS1 expression and patients' clinicopathological features was evaluated. Sensitivity and specificity of the DSCAM-AS1 expression for diagnosing breast cancer was obtained by the receiver operating characteristic (ROC) curve analysis.

RESULTS

Our results showed that the expression of DSCAM-AS1 was significantly up-regulated in breast cancerous tissues compared with the matched adjacent non-neoplastic tissues (P < 0.05). Furthermore, we observed a significant association between the DSCAM-AS1 expression and lymph node metastasis (P = 0.011) but no other clinicopathological characteristics (P > 0.05). ROC curve analysis resulted in an area under the curve (AUC) of 0.67 and showed that the DSCAM-AS1 expression level may discriminate cancerous and non-cancerous tissues with 68% sensitivity and 76% specificity.

CONCLUSION

This study provides further evidence that the expression of DSCAM-AS1 is deregulated in breast cancer and highlights its potential in breast cancer development.

Circular RNA hsa_circ_0061395 accelerates hepatocellular carcinoma progression via regulation of the miR-877-5p/PIK3R3 axis

Background

Circular RNA hsa_circ_0061395 (circ_0061395) has been reported to accelerate the advancement of hepatocellular carcinoma (HCC). However, the regulatory mechanism by which circ_0061395 modulates the progression of HCC is unclear.

Methods

The morphology and size of exosomes were analyzed by transmission electron microscope (TEM) and nanoparticle-tracking analysis (NTA). Protein levels were detected by western blotting. Expression levels of circ_0061395, microRNA (miR)-877-5p, and phosphoinositide-3-kinase regulatory subunit 3 (PIK3R3) mRNA were assessed by quantitative real time polymerase chain reaction (qRT-PCR). The proliferation, invasion, migration, cell cycle progression, and apoptosis were analyzed by cell counting kit-8 (CCK-8), plate clone, transwell, or flow cytometry assays. The targeting relationship between circ_0061395 or PIK3R3 and miR-877-5p was verified using the dual-luciferase reporter and/or RNA immunoprecipitation (RIP) assays. Xenograft assay was performed to confirm the biological function of circ_0061395 in HCC.

Results

Circ_0061395 was upregulated in HCC tissues, serum, cells, and serum-derived exosomes. Circ_0061395 silencing decreased tumor growth in vivo, and induced cell cycle arrest, apoptosis, repressed proliferation, invasion, and migration of HCC cells in vitro. MiR-877-5p was downregulated while PIK3R3 was upregulated in HCC. Circ_0061395 regulated PIK3R3 expression via competitively binding to miR-877-5p. MiR-877-5p inhibitor overturned circ_0061395 knockdown-mediated influence on malignant behaviors of HCC cells. PIK3R3 overexpression reversed the suppressive influence of miR-877-5p mimic on malignant behaviors of HCC cells.

Conclusion

Circ_0061395 facilitated HCC progression via regulating the miR-877-5p/PIK3R3 axis, providing a new perspective on the advancement of HCC.

Gynecologic cancers and non-coding RNAs: Epigenetic regulators with emerging roles

Gynecologic cancers involve the female genital organs, such as the vulva, vagina, cervix, endometrium, ovaries, and fallopian tubes. The occurrence and frequency of gynecologic cancer depends on personal lifestyle, history of exposure to viruses or carcinogens, genetics, body shape, and geographical habitat. For a long time, research into the molecular biology of cancer was broadly restricted to protein-coding genes. Recently it has been realized that non-coding RNAs (ncRNA), including long noncoding RNAs (LncRNAs), microRNAs, circular RNAs and piRNAs (PIWI-interacting RNAs), can all play a role in the regulation of cellular function within gynecological cancer. It is now known that ncRNAs are able to play dual roles, i.e. can exert both oncogenic or tumor suppressive functions in gynecological cancer. Moreover, several clinical trials are underway looking at the biomarker and therapeutic roles of ncRNAs. These efforts may provide a new horizon for the diagnosis and treatment of gynecological cancer. Herein, we summarize some of the ncRNAs that have been shown to be important in gynecological cancers.

Identification of circ_0085616 as an Upregulated and Oncogenic Circular RNA in Cervical Cancer Via the miR-503-5p-Mediated ATXN7L3 Activation

Background: Increasing evidence enhanced the recognition of circular RNAs (circRNAs) implicated in cancer progression. CircRNA_0085616 (circ_0085616) is a novel circRNA with high expression in cervical cancer (CC); its function and action mechanism are explored during this study. Methods: The measurement of circ_0085616, microRNA-503-5p (miR-503-5p), and Ataxin-7L3 (ATXN7L3) was performed via quantitative real-time polymerase chain reaction. Next, 3-(4,5-dimethylthiazol-2-y1)-2, 5-diphenyl tetrazolium bromide (MTT) and colony formation assays were implemented to analyze the proliferative ability. Cell metastasis was evaluated by using transwell migration and invasion assays. Glycolysis was analyzed by using glucose consumption, lactate and adenosine triphosphate production. Western blot was employed for protein analysis. The target binding was performed by dual-luciferase reporter assay and RNA immunoprecipitation assay. An animal experiment in vivo was conducted by xenografts. Results: Circ_0085616 was heightened and its downregulation blocked cellular proliferation, metastasis, and glycolysis in CC. Then, we found that circ_0085616 had a sponge effect on miR-503-5p and the miR-503-5p inhibitor could ameliorate the effects of circ_0085616 knockdown on CC cells. In addition, miR-503-5p directly targeted ATXN7L3 to obstruct CC cell proliferation, metastasis, and glycolytic process. Further, circ_0085616 could enhance ATXN7L3 by sequestering miR-503-5p, and the miR-503-5p/ATXN7L3 axis was also responsible for circ_0085616 on promoting CC tumorigenesis in vivo. Conclusion: It was obvious that circ_0085616 facilitated the carcinogenic effect on CC via the activation of ATXN7L3 by sponging miR-503-5p. Our study may be likely to provide a novel molecular target for CC therapy.

Paclitaxel Suppresses Hepatocellular Carcinoma Tumorigenesis Through Regulating Circ-BIRC6/miR-877-5p/YWHAZ Axis

Background

Paclitaxel is an effective chemotherapeutic agent for the treatment of cancer patients. Accumulating evidence suggests that circular RNAs (circRNAs) play critical roles in the occurrence and development of human cancers. However, there are few studies on interactions between paclitaxel and circRNAs in hepatocellular carcinoma (HCC).

Materials and Methods

Cell counting kit-8 (CCK-8) assay and colony formation assay were conducted to determine cell proliferation. Cell apoptosis was assessed by flow cytometry. The expression levels of circRNA baculoviral IAP repeat-containing 6 (circ-BIRC6), microRNA-877-5p (miR-877-5p), and tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein, zeta (YWHAZ) were detected by quantitative real-time polymerase chain reaction (qRT-PCR). The mice xenograft model was established to investigate the roles of circ-BIRC6 and paclitaxel in vivo. The interaction between miR-877-5p and circ-BIRC6 or YWHAZ was predicted by bioinformatics analysis and verified by dual-luciferase reporter assay. Western blot assay was applied for measuring the protein expression of YWHAZ.

Results

Paclitaxel suppressed HCC tumorigenesis through decreasing cell proliferation and accelerating apoptosis. Circ-BIRC6 and YWHAZ were upregulated, and miR-877-5p was downregulated in HCC tissues and cells. Paclitaxel treatment inhibited the expression of circ-BIRC6 and YWHAZ while promoted the expression of miR-877-5p. Circ-BIRC6 overexpression or miR-877-5p interference reversed the inhibitory effect of paclitaxel on HCC tumorigenesis. Moreover, miR-877-5p could specially bind to YWHAZ, and its knockdown abated the suppressive effect of circ-BIRC6 depletion on HCC tumorigenesis. Additionally, YWHAZ was identified as a direct target of miR-877-5p. Besides, circ-BIRC6 functioned as a molecular sponge of miR-877-5p to regulate YWHAZ expression.

Conclusion

Paclitaxel limited HCC tumorigenesis via modulating circ-BIRC6/miR-877-5p/YWHAZ axis, providing a novel therapeutic approach for the treatment of HCC.

Long non-coding RNA ASB16-AS1 inhibits proliferation, migration, and invasion of gastric cancer cells by regulating miR-670-3p/ATXN7L3 axis

BACKGROUND

Many long non-coding RNAs (lncRNAs) have been shown to play a role in suppressing or promoting the progression of gastric cancer (GC). However, there are still a large number of lncRNAs whose roles in the progression of GC are still unclear. Therefore, it is still necessary to identify lncRNAs that affect the proliferation, migration, and invasion of GC cells to provide potential targets for the prevention and treatment of GC.

AIM

To investigate the effect of lncRNA ASB16-AS1 on the proliferation, migration, and invasion of GC cells and the underlying mechanism.

METHODS

The expression levels of ASB16-AS1, miR-670-3p, and ATXN7L3 in human gastric mucosal cell line GES-1 and GC cell lines HGC-27, AGS, and NUGC-4 were detected by real-time fluorescent quantitative PCR (RT-qPCR) and Western blot. HGC-27 cells were divided into si-NC, si-ASB16-AS1, miR-NC, miR-670-3p, si-ATXN7L3, si-ASB16-AS1 + anti-miR-NC, si-ASB16 -AS1 + anti-miR-670-3p, si-ASB16-AS1 + pcDNA-NC, and si-ASB16-AS1 + pcDNA-ATXN7L3 groups. Cell counting kit-8 and transwell assay were used to detect cell viability and migration invasion , respectively. Dual luciferase reportor assay, RT-qPCR, and Western blot were used to determine the interaction between ASB16-AS1 and miR-670-3p and between miR-670-3p and ATXN7L3.

RESULTS

ASB16-AS1 and ATXN7L3 were highly expressed in GC cells, while miR-670-3p was lowly expressed (P < 0.05). After inhibiting the expression of ASB16-AS1, overexpressing miR-670-3p, or inhibiting the expression of ATXN7L3, the proliferation, migration, and invasion of HGC-27 cells were significantly reduced (P < 0.05). ASB16-AS1 targets and negatively regulates miR-670-3p expression. MiR-670-3p targets and negatively regulates ATXN7L3 expression. Inhibiting miR-670-3p partially reversed the effects of inhibiting ASB16-AS1 on the proliferation, migration, and invasion of HGC-27 cells (P < 0.05). Overexpressing ATXN7L3 partially reversed the effect of inhibiting ASB16-AS1 on the proliferation, migration, and invasion of HGC-27 cells (P < 0.05).

CONCLUSION

Inhibiting ASB16-AS1 inhibits the proliferation, migration, and invasion of GC cells by regulating the miR-670-3p/ATXN7L3 axis.

Regulatory noncoding RNAs and the major histocompatibility complex

The Major Histocompatibility Complex (MHC) is a 4 Mbp genomic region located on the short arm of chromosome 6. The MHC region contains many key immune-related genes such as Human Leukocyte Antigens (HLAs). There has been a growing realization that, apart from MHC encoded proteins, RNAs derived from noncoding regions of the MHC-specifically microRNAs (miRNAs) and long noncoding RNAs (lncRNAs)-play a significant role in cellular regulation. Furthermore, regulatory noncoding RNAs (ncRNAs) derived from other parts of the genome fine-tune the expression of many immune-related MHC proteins. Although the field of ncRNAs of the MHC is a research area that is still in its infancy, ncRNA regulation of MHC genes has already been shown to be vital for immune function, healthy pregnancy and cellular homeostasis. Dysregulation of this intricate network of ncRNAs can lead to serious perturbations in homeostasis and subsequent disease.

miR-877-5p Suppresses Gastric Cancer Cell Proliferation Through Targeting FOXM1

Purpose

miR-877-5p has been reported as a tumor suppressor in multiple cancers. Its role in gastric cancer, however, remains unclear. Hence, the purpose of this study was to elucidate the function, and underlying molecular mechanism, of miR-877-5p in the development of gastric cancer.

Materials and Methods

We first analyzed miR-877-5p expression using the Gene Expression Omnibus (GEO) database and detected its expression in gastric cancer and gastric epithelial cells via real-time quantitative PCR (qRT-PCR). We then assessed the role of miR-877-5p in gastric cancer proliferation, apoptosis, and cell cycling. The gene targeted by miR-877-5p was predicted by bioinformatic analysis and confirmed by dual luciferase assay. Subsequently, rescue assays were carried out to validate whether the miR-877-5p effects on gastric cancer growth are dependent on the proposed target gene.

Results

miR-877-5p levels were lower in gastric cancer than in controls, based on the GEO and qRT-PCR analyses. Overexpression of miR-877-5p significantly inhibited cell growth and cell cycle progression, whereas it promoted apoptosis. Furthermore, forkhead box M1 (FOXM1) was predicted as a target of miR-877-5p, the overexpression of which diminished the suppressive effect that upregulation of miR-877-5p had on gastric cancer cells.

Conclusion

Our study results indicate that the miR-877-5p/FOXM1 axis plays an important role in gastric cancer progression, while suggesting miR-877-5p as a novel potential therapeutic target for gastric cancer.