Two antisense RNAs-AFAP1-AS1 and MLK7-AS1-promote colorectal cancer progression by sponging miR-149-5p and miR-485-5p

Colorectal cancer (CRC) is one of the leading causes of cancer-related deaths. Antisense RNAs (asRNAs) are closely associated with cancer malignancy. This study aimed to identify the action mechanism of asRNAs in controlling CRC malignancy. Analysis of the RNA sequencing data revealed that AFAP1-AS1 and MLK7-AS1 were upregulated in CRC patients and cell lines. High levels of both asRNAs were associated with poor prognosis in patients with CRC. Both in vitro and in vivo experiments revealed that the knockdown of the two asRNAs decreased the proliferative and metastatic abilities of CRC cells. Mechanistically, AFAP1-AS1 and MLK7-AS1 decreased the levels of miR-149-5p and miR-485-5p by functioning as ceRNAs. Overexpression of miRNAs by introducing miRNA mimics suppressed the expression of SHMT2 and IGFBP5 by directly binding to the 3' UTR of their mRNA. Knockdown of both asRNAs decreased the expression of SHMT2 and IGFBP5, which was reversed by inhibition of both miRNAs by miRNA inhibitors. In vivo pharmacological targeting of both asRNAs by small interfering RNA-loaded nanoparticles showed that knockdown of asRNAs significantly reduced tumor growth and metastasis. Our findings demonstrate that AFAP1-AS1 and MLK7-AS1 promote CRC progression by sponging the tumor-suppressing miRNAs miR-149-5p and miR-485-5p, thus upregulating SHMT2 and IGFBP5.

SP1-Induced Upregulation of LncRNA AFAP1-AS1 Promotes Tumor Progression in Triple-Negative Breast Cancer by Regulating mTOR Pathway

The long non-coding RNA (lncRNA) actin fiber-associated protein-1 antisense RNA 1 (AFAP1-AS1) exerted oncogenic activity in triple-negative breast cancer (TNBC). We designed this study and conducted it to investigate the upstream regulation mechanism of AFAP1-AS1 in TNBC tumorigenesis. In this work, we proved the localization of AFAP1-AS1 in the cytoplasm. We elucidated the mechanism by which the transcription factor specificity protein 1 (SP1) modulated AFAP1-AS1 in TNBC progression, which has yet to be thoroughly studied. Dual luciferase reporter assay and chromatin immunoprecipitation (ChIP) assay revealed a strong affinity of SP1 toward the promoter regions P3 of AFAP1-AS1, proving the gene expression regulation of AFAP1-AS1 via SP1 in TNBC. Additionally, SP1 could facilitate the tumorigenesis of TNBC cells in vitro and in vivo by regulating the AFAP1-AS1 expression. Furthermore, silenced AFAP1-AS1 suppressed the expression of genes in the mTOR pathway, such as eukaryotic translation initiation factor 4B (EIF4B), mitogen-activated protein kinase-associated protein 1 (MAPKAP1), SEH1-like nucleoporin (SEH1L), serum/glucocorticoid regulated kinase 1 (SGK1), and its target NEDD4-like E3 ubiquitin protein ligase (NEDD4L), and promoted the gene expression of s-phase kinase-associated protein 2 (SKP2). Overall, this study emphasized the oncogenic role of SP1 and AFAP1-AS1 in TNBC and illustrated the AFAP1-AS1 upstream interaction with SP1 and the downstream modulatory of mTOR signaling, thus offering insights into the tumorigenesis mechanism in TNBC.

The role of AFAP1-AS1 in mitotic catastrophe and metastasis of triple-negative breast cancer cells by activating the PLK1 signaling pathway

Triple-negative breast cancer (TNBC) is characterized by fast growth, high metastasis, high invasion, and a lack of therapeutic targets. Mitosis and metastasis of TNBC cells are two important biological behaviors in TNBC malignant progression. It is well known that the long noncoding RNA AFAP1-AS1 plays a crucial role in various tumors, but whether AFAP1-AS1 is involved in the mitosis of TNBC cells remains unknown. In this study, we investigated the functional mechanism of AFAP1-AS1 in targeting Polo-like Kinase 1 (PLK1) activation and participating in mitosis of TNBC cells. We detected the expression of AFAP1-AS1 in the TNBC patient cohort and primary cells by in situ hybridization (ISH), northern blot, fluorescent in situ hybridization (FISH) and cell nucleus/cytoplasm RNA fraction isolation. High AFAP1-AS1 expression was negatively correlated with overall survival (OS), disease-free survival (DFS), metastasis-free survival (MFS) and recurrence-free survival (RFS) in TNBC patients. We explored the function of AFAP1-AS1 by transwell, apoptosis, immunofluorescence (IF) and patient-derived xenograft (PDX) models in vitro and in vivo. We found that AFAP1-AS1 promoted TNBC primary cell survival by inhibiting mitotic catastrophe and increased TNBC primary cell growth, migration and invasion. Mechanistically, AFAP1-AS1 activated phosphorylation of the mitosis-associated kinase PLK1 protein. Elevated levels of AFAP1-AS1 in TNBC primary cells increased PLK1 pathway downstream gene expression, such as CDC25C, CDK1, BUB1 and TTK. More importantly, AFAP1-AS1 increased lung metastases in a mouse metastasis model. Taken together, AFAP1-AS1 functions as an oncogene that activates the PLK1 signaling pathway. AFAP1-AS1 could be used as a potential prognostic marker and therapeutic target for TNBC.

Increased lncRNA AFAP1-AS1 expression predicts poor prognosis in gastric cancer: Evidence from published studies and followed up verification

AIM

The purpose of this study was to clarify the influence of long non-coding RNA actin fiber-associated protein-1 antisense RNA 1 (lncRNA AFAP1-AS1) on the prognosis of gastric cancer (GC).

METHODS

Based on meta-analysis, the association between the expression of AFAP1-AS1 and the prognosis of GC was estimated. GC tissue and non-cancer tissues from 136 patients were determined by quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) and verified by Gene Expression Profiling Interactive Analysis (GEPIA). Kaplan-Meier and Cox proportional hazards models were conducted to analyze the correlation between AFAP1-AS1 expression and GC prognosis.

RESULTS

The pooled analysis from five studies revealed that the AFAP1-AS1 expression was significantly associated with GC overall survival (hazard ratio (HR) = 2.49 and 95% confidence interval (95% CI): 2.02-3.08, p  <  0.001). Compared with non-cancer tissues, AFAP1-AS1 expression level of GC tissues were significantly upregulated (p  <  0.001), which was confirmed by the results of GEPIA. The area under the receiver-operating characteristic (ROC) curve was 0.893, and the high expression of AFAP1-AS1 was correlated with poor prognosis in patients with GC (p = 0.005). Clinical grade (HR = 1.912, 95% CI: 1.246-2.934, p = 0.003), pathologic tumor node metastasis (pTNM) (HR = 2.393, 95% CI: 1.431-4.033, p = 0.001), log odds of positive lymph nodes (LODDS) (HR = 2.910, 95% CI: 1.787-4.793, p  <  0.001) and AFAP1-AS1 expression (HR = 2.393, 95% CI: 1.869-3.064, p  <   0.001) were independent prognostic factors for GC revealed by multivariate Cox-regression analysis.

CONCLUSION

This study demonstrated that the AFAP1-AS1 may be a novel biomarker for the diagnosis and prognosis of GC.

A Review on the Role of AFAP1-AS1 in the Pathoetiology of Cancer

AFAP1-AS1 is a long non-coding RNA which partakes in the pathoetiology of several cancers. The sense protein coding gene from this locus partakes in the regulation of cytophagy, cell motility, invasive characteristics of cells and metastatic ability. In addition to acting in concert with AFAP1, AFAP1-AS1 can sequester a number of cancer-related miRNAs, thus affecting activity of signaling pathways involved in cancer progression. Most of animal studies have confirmed that AFAP1-AS1 silencing can reduce tumor volume and invasive behavior of tumor cells in the xenograft models. Moreover, statistical analyses in the human subjects have shown strong correlation between expression levels of this lncRNA and clinical outcomes. In the present work, we review the impact of AFAP1-AS1 in the carcinogenesis.

Silencing of LncRNA AFAP1-AS1 Inhibits Cell Proliferation in Oral Squamous Cancer by Suppressing CCNA2

Background

Evidence has indicated that dysregulation of long noncoding RNAs (lncRNA) is a critical factor in the occurrence of many diseases, including cancer. The lncRNA AFAP1-AS1 has been shown to participate in oncogenesis, metastasis, or drug resistance in many types of cancer. However, the potential role of AFAP1-AS1 in oral squamous cell carcinoma (OSCC) has not been fully elucidated.

Methods

Bioinformatics analysis was performed to compare AFAP1-AS1 expression levels in OSCC cancer samples and in normal controls. The biological function of AFAP1-AS1 was studied through loss-of-function assays. To study the potential mechanisms, high-throughput sequencing was applied to OSCC cancer samples and a series of bioinformatics analyses were performed. The effects of AFAP1-AS1 on OSCC tumor growth was evaluated by in vivo xenograft tumor formation assays.

Results

Bioinformatics analyses indicated that AFAP1-AS1 was upregulated in OSCC. Overexpression of AFAP1-AS1 was positively correlated with lymph node metastasis, tumor stage, and pathological grade. Down-regulation of AFAP1-AS1 in OSCC led to decreased proliferation in vitro and, notably, inhibition of tumor growth in vivo. Further research indicated that AFAP1-AS1 regulated OSCC cell proliferation by targeting CCNA2.

Conclusion

AFAP1-AS1 promotes tumor proliferation and indicates a poor prognosis in OSCC, providing a potential therapeutic strategy.

Long non-coding RNA AFAP1-AS1 promotes thyroid cancer progression by sponging miR-204-3p and upregulating DUSP4

Long non-coding RNA (lncRNA) actin filament-associated protein 1-antisense RNA 1 (AFAP1-AS1), shows crucial regulatory function in tumor progression. Nonetheless, the biological function and underlying mechanism of AFAP1-AS1 in the progression of thyroid cancer is still unclear. Expressions of AFAP1-AS1, miR-204-3p, and DUSP4 were quantified utilizing qRT-PCR and/or Western blot. In loss-of-function and gain-of-function assays, cell proliferation, migration and invasion were appraised by CCK-8 assay, wound healing assay, Transwell migration and invasion assays, respectively. Luciferase reporter assay was employed for validating the interaction between miR-204-3p and AFAP1-AS1 or the 3'UTR of dual specificity phosphatase 4 (DUSP4). AFAP1-AS1 was highly expressed in thyroid cancer tissues and cell lines. Highly expressed AFAP1-AS1 was in association with advanced TNM stage and positive lymph node metastasis. Knockdown of AFAP1-AS1 suppressed the proliferation, migration and invasion of thyroid cancer cells, and overexpression of AFAP1-AS1 induced a reversed effect. MiR-204-3p was targetedly repressed by AFAP1-AS1, and miR-204-3p could negatively regulate DUSP4 expression. AFAP1-AS1 augmented the expression of DUSP4 via repressing miR-204-3p, and the effects of AFAP1-AS1 overexpression on thyroid cancer cells were also partly abolished by miR-204-3p restoration. In summary, AFAP1-AS1 facilitates thyroid cancer cell proliferation, migration, and invasion by regulating miR-204-3p/DUSP4 axis.

Silencing of AFAP1-AS1 lncRNA impairs cell proliferation and migration by epigenetically promoting DUSP5 expression in pre-eclampsia

As a unique and common obstetric complication of pregnant women, pre-eclampsia (PE) has been the first leading cause of maternal and perinatal morbidity and mortality in the world. Mounting studies have demonstrated that an abnormality of long noncoding RNA (lncRNA) expression was related to the pathological process of PE. Here, we showed that lncRNA AFAP1-AS1 was markedly downregulated in pre-eclamptic placentas. We further investigated the mechanism underlying the regulatory role of AFAP1-AS1 in PE using human trophoblast cells. In vitro functional assays revealed that AFAP1-AS1 knockdown inhibited trophoblast proliferation, migration, and invasion. Moreover, AFAP1-AS1 interacts with EZH2 and inhibits DUSP5 expression through modulating H3K27m3 in the DUSP5 promoter of trophoblast cells, thus being involved in PE pathogenesis. Overall, these findings suggest that AFAP1-AS1 could potentially become a prognostic biomarker as well as a new therapeutic target for PE.

LncRNA AFAP1-AS1 Modulates the Proliferation and Invasion of Gastric Cancer Cells by Regulating AFAP1 via miR-205-5p

Purpose

The present study investigated the expression and function of the long noncoding RNA (lncRNA) actin filament associated protein 1 antisense RNA1 (AFAP1-AS1) related to gastric cancer (GC), based on previous results from a microarray analysis.

Methods

Real-time quantitative polymerase chain reaction (qPCR) was used to verify the expression of AFAP1-AS1 in 97 fresh GC tissues and paired non-GC tissues, as well as in six different GC cell lines (BGC-823, SGC-7901, MGC-803, AGS, MKN-45, and MKN-28). The expression levels were subsequently correlated with the clinicopathological features of patients. siRNA against AFAP1-AS1 was transfected into GC cell lines, and cell proliferation, migration, and invasion were detected before and after silencing of AFAP1-AS1 expression. Luciferase reporter gene analysis was used to confirm the target gene of microRNA-205-5p (miR-205-5p) in 293T cells. The potential mechanism was subsequently investigated.

Results

qPCR results showed that AFAP1-AS1 was significantly overexpressed in GC tumor tissues and also GC cell lines, comparing to their paired non-GC tissues. Furthermore, statistical analysis revealed that the overexpression of AFAP1-AS1 was significantly correlated with tumor size (p=0.018) and grade of differentiation (p=0.042). Subsequently, artificially decreasing the expression of AFAP1-AS1 with its specific siRNA dramatically inhibited the proliferation, migration and invasion of GC cell lines (SGC-7901 and BGC-823 cells). Mechanical analysis suggested that AFAP1-AS1 is involved in regulation of its maternal gene, AFAP1, at both mRNA level and protein level. Luciferase reporter gene assay indicated that lncRNA AFAP1-AS1, as a ceRNA, is able to sponge miR-205-5p. Moreover, miR-205-5p has been well demonstrated to participate in the regulation of AFAP1 expression and the phenotypes of GC cells, including proliferation, migration and invasion.

Conclusion

AFAP1-AS1, as a novel biomarker of GC, promotes the proliferation migration and invasion of GC cells and function as ceRNA to target AFAP1 by sponging miR-205-5p.

Long non-coding RNA AFAP1-AS1 facilitates prostate cancer progression by regulating miR-15b/IGF1R axis

BACKGROUND

Prostate cancer (PCa) is a commonly diagnosed malignant cancer and is the second highest cause of cancer related death in men worldwide. Enzalutamide is the second-generation inhibitor of androgen receptor signaling and is the fundamental drug for the treatment of advanced PCa. However, the disease will eventually progress to metastatic castration-resistant prostate cancer (CRPC) and aggressive neuroendocrine prostate cancer (NEPC) because of androgen-deprivation therapy (ADT) resistance. The aim of the study was to investigate the role of long non-coding RNA (lncRNA) AFAP1-AS1 in ADT resistance.

METHODS

Quantitative real-time PCR analysis (qPCR) was used to assess the expression of AFAP1-AS1 in PCa cell lines and tissues. Cell proliferation and invasion were assessed after AFAP1-AS1 knockdown using Cell Counting Kit (CCK)-8 and Transwell assay, respectively. A dual-luciferase reporter gene assay was carried out to validate the regulatory relationship among AFAP1-AS1, microRNA (miR)-15b, and insulin-like growth factor1 receptor (IGF1R).

RESULTS

AFAP1-AS1 level was markedly increased in castration-resistant C4-2 cells and NE-like cells (PC3, DU145, and NCI-H660), compared with androgen-sensitive LNCaP cells. Enzalutamide treatment increased the expression of AFAP1-AS1 in vitro and in vivo. Functionally, AFAP1-AS1 knockdown repressed tumor cell proliferation and invasion. Mechanistically, AFAP1-AS1 functioned as an oncogene in PCa through binding to miR-15b and destroying its tumor suppressor function. Finally, we identified that AFAP1-AS1 up-regulated IGF1R expression by competitively binding to miR-15b to de-repress IGF1R.

CONCLUSION

AFAP1-AS1 facilitates PCa progression by regulating miR-15b/IGF1R axis, indicating that AFAP1-AS1 may serve as a diagnostic biomarker and therapeutic target for PCa.

LncRNA AFAP1-AS1 promotes M1 polarization of macrophages and osteogenic differentiation of valve interstitial cells

Little is known about the biological functions and underlying mechanisms of long non-coding RNA AFAP1-AS1 in degenerative calcified aortic valve disease (DCAVD). This study aims to explore whether AFAP1-AS1 regulates macrophage polarization in aortic valve calcification. Macrophage polarization and AFAP1-AS1 expression were detected in normal and calcified aortic valves of DCAVD patients. To explore the effect of AFAP1-AS1 on macrophage polarization, gain and loss of function were performed in THP-1 cells, and the percentage of M1 and M2 and the expressions of M1 and M2 markers were analyzed. Meanwhile, osteogenic differentiation was examined in valve interstitial cells (VICs). Compared with normal valves, there were more M1, less M2, and high AFAP1-AS1 expressions in calcified aortic valves, which may indicate a relationship between AFAP1-AS1 and macrophage polarization. AFAP1-AS1 overexpression promoted M1 polarization in lipopolysaccharide (LPS) and interferon gamma (IFN-γ)-treated THP-1 cells but inhibited M2 polarization, as well as augmented VIC osteogenic differentiation. On the contrary, the silence of AFAP1-AS1 could induce macrophage to M2-type and inhibit VIC osteogenic differentiation. These results elucidate that AFAP1-AS1 can promote M1 macrophages polarization to aggravate VIC osteogenic differentiation, playing a role in aortic valve calcification.

AFAP1-AS1: a rising star among oncogenic long non-coding RNAs

Long non-coding RNAs (lncRNAs) have become a hotspot in biomedical research. This interest reflects their extensive involvement in the regulation of the expression of other genes, and their influence on the occurrence and development of a variety of human diseases. Actin filament associated protein 1-Antisense RNA 1(AFAP1-AS1) is a recently discovered oncogenic lncRNA. It is highly expressed in a variety of solid tumors, and regulates the expression of downstream genes and signaling pathways through adsorption and competing microRNAs, or by the direct binding to other proteins. Ultimately, AFAP1-AS1 promotes proliferation, chemotherapy resistance, and resistance to apoptosis, maintains stemness, and enhances invasion and migration of tumor cells. This paper summarizes the research concerning AFAP1-AS1 in malignant tumors, including the clinical application prospects of AFAP1-AS1 as a potential molecular marker and therapeutic target of malignant tumors. We also discuss the limitations in the knowledge of AFAP1-AS1 and directions of further research. AFAP1-AS1 is expected to provide an example for studies of other lncRNA molecules.

Long non-coding RNA AFAP1-AS1 facilitates ovarian cancer progression by regulating the miR-107/PDK4 axis

Background

Abnormally expressed in various tumors, long non-coding RNAs (lncRNAs) feature prominently in tumor development, yet little is still known regarding the functional roles of lncRNA AFAP1 antisense RNA 1 (AFAP1-AS1) in ovarian cancer (OC).

Methods

The relative expression levels of lncRNA AFAP1-AS1, microRNA (miR)-107 and pyruvate dehydrogenase kinase isozyme 4 (PDK4) mRNA were assessed by quantitative real-time PCR. PDK4, PCNA and cyclin D1 expression levels were determined using Western blot analysis. Bioinformatics analysis and dual-luciferase gene reporter assay were conducted for identifying and validating the binding sequences between AFAP1-AS1 and miR-107, as well as between miR-107 and PDK4. Cell counting kit-8 assay was employed for detecting cell proliferation. Cell migration and invasion abilities were examined using Transwell assays.

Results

The present study revealed that AFAP1-AS1 expression was elevated in OC cells and tissues. AFAP1-AS1 expression and FIGO stage were positively correlated. AFAP1-AS1 knockdown repressed OC cell proliferation, migration and invasion. AFAP1-AS1 functioned as a sponge of miR-107, and miR-107 reversed the effects of AFAP1-AS1 on OC cells. It was validated that miR-107 was able to bind to PDK4, and AFAP1-AS1 regulated PDK4 expression by competitively binding with miR-107. Additionally, miR-107 modulated OC cell proliferation, migration and invasion via targeting PDK4.

Conclusions

LncRNA AFAP1-AS1 serves as a tumor driver in the pathogenesis of OC via the miR-107/PDK4 axis.

SP1-induced AFAP1-AS1 contributes to proliferation and invasion by regulating miR-497-5p/CELF1 pathway in nasopharyngeal carcinoma

Nasopharyngeal carcinoma is a type of otolaryngological malignancy with high incidence. Long non-coding RNAs (lncRNAs) are closely related to nasopharyngeal carcinoma. LncRNA AFAP1-AS1 (AFAP1-AS1) has been found to play important roles in nasopharyngeal carcinoma progression and poor prognosis. However, the mechanism underlying AFAP1-AS1 in regulating nasopharyngeal carcinoma is still unclear. In current study, AFAP1-AS1 was found to be up-regulated in nasopharyngeal carcinoma tissues and cells. AFAP1-AS1 overexpression and knockdown were conducted in nasopharyngeal carcinoma cells. The results proved that AFAP1-AS1 promoted the survival and migration of nasopharyngeal carcinoma cells. Additionally, specificity protein 1 (SP1) was enhanced in nasopharyngeal carcinoma tissues and cells, and induced AFAP1-AS1 expression. The interaction between AFAP1-AS1 and miR-497-5p was confirmed. AFAP1-AS1 was demonstrated to regulate CELF1, a target gene of miR-497-5p. Further functional analysis revealed that AFAP1-AS1 knockdown attenuated SP1-induced nasopharyngeal carcinoma progression. These results indicate that SP1-induced AFAP1-AS1 facilitates nasopharyngeal carcinoma progression by regulating miR-497-5p/CELF1 pathway, which provides a new target for nasopharyngeal carcinoma treatment.

Long non-coding RNA AFAP1-AS1 promotes cell growth and inhibits apoptosis by binding to specific proteins in germinal center B-cell-like diffuse large B-cell lymphoma

Germinal center B-cell-like diffuse large B-cell lymphoma (GCB-DLBCL) is a common subtype of lymphoma in adults. Previously, we found that actin filament-associated protein 1-antisense RNA 1 (AFAP1-AS1) is among the most overexpressed lncRNAs in GCB-DLBCL. In this study, we explored its biological functions and molecular mechanisms in the progression of GCB-DLBCL. We discovered, via bioinformatics, that patients with a high expression of AFAP1-AS1 had significantly poor disease-free survival (DFS) and overall survival (OS). Subsequent assays demonstrated that AFAP1-AS1 knockdown inhibited cell proliferation and prompted arrest of the G0/G1 cell cycle and apoptosis in GCB-DLBCL cell lines. Proteomics analysis indicated that hundreds of proteins were deregulated after AFAP1-AS1 knockdown and KEGG pathway analysis revealed that the deregulated proteins belonged to multiple signaling pathways, such as "B-cell receptor signaling pathway". Moreover, in the comprehensive identification of proteins that bind to RNA (by ChIRP-MS), several proteins associated with RNA splicing were identified (e.g., SFPQ, NONO, SRSF2, SRSF6, and KHSRP) that could specifically bind to AFAP1-AS1, which was confirmed by parallel reaction monitoring assay (PRM). Conclusively, we demonstrated that AFAP1-AS1 is a possible prognostic marker of poor outcomes in GCB-DLBCL patients and could modulate gene expression through connecting to specific proteins to practice its oncogenic role in GCB-DLBCL.

LncRNA AFAP1-AS1 modulates the sensitivity of paclitaxel-resistant prostate cancer cells to paclitaxel via miR-195-5p/FKBP1A axis

LncRNA AFAP1-AS1 has been corroborated to function in diverse cancers. Our aim was to investigate the molecular mechanism of AFAP1-AS1 in PTX resistance in PCa. The levels of AFAP1-AS1, miR-195-5p, and FKBP1A were checked by qRT-PCR. 3-(4, 5-Dimethylthiazol-2-yl)-2, 5-Diphenyltetrazolium Bromide (MTT) assay was employed to assess the resistance of PTX-resistant PCa cells to PTX. Flow cytometry was introduced to evaluate cell apoptosis. The protein levels of C-caspase 3 were determined by western blot. The starBase was used to predict the interaction between miR-195-5p and AFAP1-AS1. Xenograft tumor model was established to investigate the biological role of AFAP1-AS1 in PTX resistance in vivo. The levels of AFAP1-AS1 and FKBP1A were upregulated in PCa tissues and cells, as well as PTX-resistant PCa cells, while the expression of miR-195-5p was declined. Knockdown of AFAP1-AS1 promoted the sensitivity of PTX-resistant PCa cells to PTX, induced apoptosis of PTX-resistant PCa cells, whereas the impacts could be reversed by reducing the expression of miR-195-5p. FKBP1A overexpression could rescue the effects of miR-195-5p-mediated enhancement on the sensitivity of PTX-resistant PCa cells to PTX, promotion on apoptosis of PTX-resistant PCa cells. AFAP1-AS1 interacted with miR-195-5p and miR-195-5p could bind to the 3'UTR of FKBP1A. AFAP1-AS1 silencing inhibited the tumor growth in mice implanted with PC3-TXR cell. The protein level of PCNA was decreased in PC3-TXR cells transfected with sh-AFAP1-AS1, while the expression of C-caspase 3 was upregulated. AFAP1-AS1 silencing attenuated the resistance of PTX-resistant PCa cells to PTX by downregulating FKBP1A via sponging miR-195-5p.

Long non-coding RNA AFAP1-AS1 accelerates the progression of melanoma by targeting miR-653-5p/RAI14 axis

BACKGROUND

Melanoma is the most aggressive skin cancer that derived from pigment cells, accounting for the majority of the skin-cancer-related deaths. Despite great development and evolution have been made in surgery, radiotherapy and adjuvant chemotherapy, the prognosis of melanoma patients exhibited no significant improvement. Long noncoding RNAs (lncRNAs) are frequently dysregulated and involved in the development of cancers. LncRNA AFAP1-AS1 has been explored in various cancers, whereas its role and regulatory mechanism in melanoma are not well understood.

METHODS

The expression of AFAP1-AS1 was detected by qRT-PCR. CCK-8, colony formation, transwell and western blot assays were performed to investigate the biological role of AFAP1-AS1 in melanoma. Male BALB/c nude mice were applied for in vivo experiments. The interaction among AFAP1-AS1, miR-653-5p and RAI14 was investigated by RNA pull down, RIP and luciferase reporter assays.

RESULTS

AFAP1-AS1 was highly expressed in melanoma cell lines. Suppression of AFAP1-AS1 impaired cell proliferation, migration, invasion and EMT in melanoma. Moreover, AFAP1-AS1 was a ceRNA of RAI14 by competitively binding with miR-653-5p. Besides, miR-653-5p overexpression or RAI14 inhibition could repress tumor growth. Eventually, rescue assays indicated that the function of AFAP1-AS1 in the cellular process of melanoma was dependent on miR-653-5p and RAI14.

CONCLUSIONS

AFAP1-AS1 exerts its oncogenic function in melanoma by targeting miR-653-5p/RAI14 axis.

Exosome-mediated lncRNA AFAP1-AS1 promotes trastuzumab resistance through binding with AUF1 and activating ERBB2 translation

BACKGROUND

Although trastuzumab provides significant clinical benefit for HER2-positive breast cancers, responses are limited by the emergence of resistance. Recent evidence suggests that long noncoding RNAs (lncRNAs) play important roles in tumorigenesis and chemoresistance. However, the regulatory mechanism of lncRNAs in trastuzumab resistance is not well established to date. In this research, we identified the differentially expressed lncRNA and investigated its regulatory role in trastuzumab resistance of breast cancer.

METHODS

LncRNA microarray and qRT-PCR were performed to identify the dysregulated lncRNAs. Transmission electron microscopy, differential ultracentrifugation and qRT-PCR were used to verify the existence of exosomal AFAP1-AS1 (actin filament associated protein 1 antisense RNA 1). Bioinformatics prediction, RNA fluorescence in situ hybridization (RNA-FISH) and immunoprecipitation assays were performed to identify the direct interactions between AFAP1-AS1 and other associated targets, such as AU-binding factor 1 (AUF1) and ERBB2. Finally, a series gain- or loss-functional assays were done to prove the precise role of AFAP1-AS1 in trastuzumab resistance.

RESULTS

AFAP1-AS1 was screened out due to its higher expression in trastuzumab-resistant cells compared to sensitive cells. Increased expression of AFAP1-AS1was associate with poorer response and shorter survival time of breast cancer patients. AFAP1-AS1 was upregulated by H3K27ac modification at promoter region, and knockdown of AFAP1-AS1 reversed trastuzumab resistance. Moreover, extracellular AFAP1-AS1 secreted from trastuzumab resistant cells was packaged into exosomes and then disseminated trastuzumab resistance of receipt cells. Mechanically, AFAP1-AS1 was associated with AUF1 protein, which further promoted the translation of ERBB2 without influencing the mRNA level.

CONCLUSION

Exosomal AFAP1-AS1 could induce trastuzumab resistance through associating with AUF1 and promoting ERBB2 translation. Therefore, AFAP1-AS1 level may be useful for prediction of trastuzumab resistance and breast cancer treatment.

LncRNA AFAP1-AS1 promotes osteoblast differentiation of human aortic valve interstitial cells through regulating miR-155/SMAD5 axis

AIM

Degenerative calcific aortic valve disease (DCAVD) is a common valve disease characterized by massive calcium deposits in the aortic valve. Osteoblast differentiation of valve interstitial cells (VICs) is responsible for the formation of calcific nodules. This study aims to explore the function and underlying mechanism of long non-coding RNA (lncRNA) AFAP1-AS1 (actin filament-associated protein 1 antisense RNA 1) in the pathogenesis of DCAVD.

METHODS

AFAP1-AS1, miR-155 and mRNA levels were detected by qRT-PCR. Protein levels were measured by Western blot. Calcification deposition was examined by Alizarin Red staining. The interaction between AFAP1-AS1 and miR-155, as well as miR-155 and SMAD5 was evaluated using luciferase reporter assay.

RESULTS

AFAP1-AS1 expression was increased both in calcified aortic valves from DCAVD patients and after osteogenic induction in human VICs. Furthermore, AFAP1-AS1 overexpression promoted osteogenic differentiation of VICs, whereas AFAP1-AS1 knockdown inhibited osteogenic differentiation. Mechanistically, AFAP1-AS1 acted as a sponge for miR-155 to elevate SMAD5 expression. Further functional assays revealed that miR-155 mimic and SMAD5 silencing effectively reversed AFAP1-AS1-promoted osteogenic differentiation of VICs.

CONCLUSION

Collectively, AFAP1-AS1 promotes osteogenic differentiation of VICs, at least in part, by sponging miR-155 to upregulate SMAD5. This study sheds new light on lncRNA-directed therapeutics in DCAVD.

AFAP1-AS1 induces cisplatin resistance in non-small cell lung cancer through PI3K/AKT pathway

Cisplatin (DDP)-resistance in non-small cell lung carcinoma (NSCLC) severely influences the prognosis of affected patients. This study aims to uncover the potential role of AFAP1-AS1 in DDP-resistant NSCLC and the underlying mechanism. The expression level of AFAP1-AS1 in DDP-resistant NSCLC patients and DDP-resistant A549 cells (A549/DDP) was determined. Proliferative, cell cycle distribution, apoptotic, migratory and invasive changes in A549/DDP cells transfected with si-AFAP1-AS1 were assessed. Western blot analyses were conducted to examine the protein levels of phosphorylated protein kinase B (p-AKT), AKT, E-cadherin, N-cadherin, vimentin and snail in A549/DDP cells. Furthermore, the ubcellular distribution of AFAP1-AS1 was analyzed. Through RNA immunoprecipitation (RIP) assay, the interaction between AFAP1-AS1 and enhancer of zeste homolog 2 (EZH2) was explored. Finally, the regulatory effect of EZH2 on the PI3K/AKT pathway was investigated by western blot analysis. AFAP1-AS1 was upregulated in DDP-resistant NSCLC patients and A549/DDP cells. Transfection with si-AFAP1-AS1 attenuated the proliferative, migratory and invasive abilities, arrested cell cycle in G0/G1 phase, and stimulated apoptosis of A549/DDP cells. Silencing of AFAP1-AS1 upregulated E-cadherin and downregulated N-cadherin, vimentin and snail expression levels. Furthermore, AFAP1-AS1 was verified to interact with EZH2. The relative expression of EZH2 was reduced by transfection of A549/DDP cells with si-AFAP1-AS1. Silencing of EZH2 inhibited the activation of PI3K/AKT pathway. In conclusion, AFAP1-AS1 accelerates the proliferative and metastatic abilities of A549/DDP cells, whereas inhibits the apoptosis of A549/DDP cells, by interacting with EZH2 to activate the PI3K/AKT pathway; thus, inducing DDP resistance in NSCLC.

Long non-coding RNA AFAP1-AS1 promotes proliferation and invasion in prostate cancer via targeting miR-512-3p

BACKGROUND (OBJECTIVE)

In the development of tumor therapy, the role of long non-coding RNA actin filagenin 1 antisense RNA 1 (1ncRNA AFAP1-AS1) is quite significant, but the actual role of AFAP1-AS1 in the treatment of prostate cancer has not been determined. In view of this, the author took AFAP1-AS1 as the research object to design an experimental study, and conducted an in-depth exploration of the pathogenesis of prostate cancer.

METHODS

RT-qPCR was used to detect the expression of AFAP1-AS1 and miR-512-3p in prostate cancer tissues and cell lines. Perforation, flow cytometry and CCK-8 were used to detect the effects of cell proliferation, migration and invasion of mir-512-3p and a AFAP1-AS1. And the luciferase reporter gene was used to detect the downstream target gene of AFAP1-AS1, and the expression of CDK4, CDK6 and CCND1 protein was detected by Western blot.

RESULTS

AFAP1-AS1 is highly expressed in prostate cancer tissues and cell lines. The expression level of AFAP1-AS1 is correlated with histological grade and distant metastasis. The overall level of patients with high expression of AFAP1-AS1 is low, and their survival rate is relatively low. Silencing AFAP1-AS1 can significantly increase the proliferation and migration of prostate cancer cells. AFAP1-AS1 silencing induces cell cycle arrest at G0/G1 phase. The downstream target of AFAP1-AS1 was mir-512-3p. The role of AFAP1-AS1 in the progression of prostate cancer cells was mediated by mir-512-3p.

CONCLUSION

AFAP1-AS1 regulates miR-512-3p, so as to realize the regulation effect on the proliferation, invasion and migration of prostate cancer cells, and thereby promote the occurrence and development of prostate cancer, so as to provide the corresponding program for the treatment of prostate cancer. Abberivation: ADPC, androgen-dependent prostate cancer; CRPC, castrated prostate cancer; RNA1 AFAP1-Asl, Actin fiber-associated protein 1-anti-RNA1; miRNAs, MicroRNAs.

LncRNA AFAP1-AS1 Supresses miR-139-5p and Promotes Cell Proliferation and Chemotherapy Resistance of Non-small Cell Lung Cancer by Competitively Upregulating RRM2

Non-small cell lung cancer (NSCLC) is the leading cause of cancer-related death worldwide. This study aims to understand the underlying mechanism of lncRNA, actin filament-associated protein 1 antisense RNA 1(AFAP1-AS1) in mediating chemotherapeutic resistance in NSCLC. The levels of AFAP1-AS1 in NSCLC tissues and cells were determined using RT-PCR. The protein levels of RRM2, EGFR, and p-AKT were analyzed using Western blotting. Binding between AFAP1-AS1 and miR-139-5p was confirmed using dual luciferase reporter and RNA immunoprecipitation (RIP) assays, and binding between miR-139-5p and RRM2 was confirmed by a dual luciferase reporter assay. NSCLC cell proliferation, apoptosis, and colony formation were examined using MTT, flow cytometry, and colony formation assays, respectively. It was found that AFAP1-AS1 expression was upregulated in NSCLC tissues and cells. In addition, AFAP1-AS1 bound to and downregulated the expression of miR-139-5p, which was reduced in NSCLC tissues. Knockdown of AFAP1-AS1 and overexpression of miR-139-5p inhibited NSCLC cell proliferation, colony formation and chemotherapy resistance and increased cell apoptosis. Additionally, AFAP1-AS1 upregulates RRM2 expression via sponging miR-139-5p. Furthermore, AFAP1-AS1 enhanced NSCLC cell proliferation and chemotherapy resistance through upregulation of RRM2 by inhibiting miR-139-5p expression. Moreover, RRM2 promoted cellular chemotherapy resistance by activating EGFR/AKT. Finally, knockdown of AFAP1-AS1 significantly suppressed tumor growth and chemoresistance in nude mice. In conclusion, AFAP1-AS1 promoted chemotherapy resistance by supressing miR-139-5p expression and promoting RRM2/EGFR/AKT signaling pathway in NSCLC cells.

LncRNA AFAP1-AS1 promotes tumorigenesis and epithelial-mesenchymal transition of osteosarcoma through RhoC/ROCK1/p38MAPK/Twist1 signaling pathway

Background

An increasing number of studies have demonstrated that long non-coding RNAs (lncRNAs) play pivotal roles in cancer onset and development. LncRNA AFAP1-AS1 has been validated to be abnormally upregulated and play oncogenic roles in various malignant tumors. The biological role and mechanism of AFAP1-AS1 in OS (osteosarcoma) remains unclear.

Methods

Quantitative reverse transcription PCR (qRT-PCR) is applied to examine AFAP1-AS1 expression in OS tissues and OS cell lines. The function of AFAP1-AS1 in OS cells is investigated via in-vitro and in-vivo assays. Western bolt and rescue experiments are applied to detect the expression changes of key molecules including epithelial-mesenchymal transition markers and identify the underlying molecular mechanism. RNA immunoprecipitation is performed to reveal the interaction between AFAP1-AS1 and RhoC.

Results

AFAP1-AS1 expression is upregulated in human OS tissues and cell lines. AFAP1-AS1 knockdown induces OS cell apoptosis and cell cycle G0/G1 arrest, suppresses OS cells growth, migration, invasion, vasculogenic mimicry formation and epithelial-mesenchymal transition (EMT), and affects actin filament integrity. AFAP1-AS1 knockdown suppresses OS tumor formation and growth in nude mice. AFAP1-AS1 knockdown elicits a signaling inhibition including decreased levels of RhoC, ROCK1, p38MAPK and Twist1. Moreover, AFAP1-AS1 interacts with RhoC. Overexpression of RhoC can partly reverse AFAP1-AS1 downregulation-induced cell EMT inhibition.

Conclusions

AFAP1-AS1 is overexpressed in osteosarcoma and plays an oncogenic role in osteosarcoma through RhoC/ROCK1/p38MAPK/Twist1 signaling pathway, in which RhoC acts as the interaction target of AFAP1-AS1. Our findings indicated a novel molecular mechanism underlying the tumorigenesis and progression of osteosarcoma. AFAP1-AS1 could serve as a promising therapeutic target in OS treatment.

Electronic supplementary material

The online version of this article (10.1186/s13046-019-1363-0) contains supplementary material, which is available to authorized users.

AFAP1-AS1 Promotes Proliferation of Pituitary Adenoma Cells through miR-103a-3p to Activate PI3K/AKT Signaling Pathway

BACKGROUND

We previously found that AFAP1-AS1 regulates the cell growth of pituitary tumor cells; however, the mechanism still remains unclear. Here, we investigated whether AFAP1-AS1 acts as a competing endogenous RNA of miR-103a-3p to regulate pituitary adenoma growth via the PI3K/AKT pathway.

METHODS

The bind between AFAP1-AS1 and rno-miR-103a-3p was measured by luciferase reporter assay, and rno-miR-103a-3p expression was measured by quantitative reverse transcription polymerase chain reaction. Proliferation, cell cycle, and apoptosis were measured by cell counting kit 8 and flow cytometry. Rat growth hormone (GH) and prolactin (PRL) levels in culture supernatant of GH3 and MMQ cells were measured by enzyme-linked immunosorbent assay.

RESULTS

AFAP1-AS1 binds to rno-miR-103a-3p in rat pituitary adenoma cells. Additionally, rno-miR-103a-3p overexpression suppressed rat pituitary adenoma cell proliferation, induced cell apoptosis, arrested cell cycle in the G/S phase, reduced GH and PLR secretion, and inhibited the PI3K/AKT signaling pathway. Activated PI3K/AKT signaling pathway revised the effect of rno-miR-103a-3p overexpression on proliferation and GH and PLR secretion. Coexpression of both si-AFAP1-AS1 and rno-miR-103a-3p inhibitor promoted cell proliferation and cell cycle progression, reduced cell apoptosis, enhanced GH and PLR secretion, and activated the PI3K/AKT signaling pathway in rat pituitary adenoma cells.

CONCLUSION

We found that AFAP1-AS1 and miR-103a-3p could be a potential therapeutic target for pituitary adenoma.

Long noncoding RNA actin filament-associated protein 1 antisense RNA 1 promotes malignant phenotype through binding with lysine-specific demethylase 1 and repressing HMG box-containing protein 1 in non-small-cell lung cancer

The number of documented long noncoding RNAs (lncRNAs) has dramatically increased, and their biological functions and underlying mechanisms in pathological processes, especially cancer, remain to be elucidated. Actin filament‐associated protein 1 antisense RNA 1 (AFAP1‐AS1) is a 6810‐nt lncRNA located on chromosome 4p16.1 that was first reported to be upregulated in esophageal adenocarcinoma tissues and cell lines. Here we reported that AFAP1‐AS1, recruiting and binding to lysine‐specific demethylase 1 (LSD1), was generally overexpressed in human non‐small‐cell lung cancer (NSCLC) tissues using quantitative real‐time PCR. Higher AFAP1‐AS1 expression was significantly correlated with larger tumor size (P = .008), lymph node metastasis (P = .025), higher TNM stage (P = .024), and worse overall survival in NSCLC patients. In vitro experiments revealed that AFAP1‐AS1 downregulation inhibited cell migration and induced apoptosis; AFAP1‐AS1 knockdown also hindered tumorigenesis in vivo. Moreover, mechanistic investigations including RNA immunoprecipitation and ChIP assays validated that AFAP1‐AS1 repressed HMG box‐containing protein 1 (HBP1) expression by recruiting LSD1 to the HBP1 promoter regions in PC‐9 and H1975 cells. Furthermore, HBP1 functions as a tumor suppressor, and its ectopic expression hindered cell proliferation. Rescue assays determined that the oncogenic effect of AFAP1‐AS1 is partially dependent on the epigenetic silencing of HBP1. In conclusion, our results indicate that AFAP1‐AS1 is carcinogenic and that the AFAP1‐AS1/LSD1/HBP1 axis could constitute a new therapeutic direction for NSCLC.

Cloning and characterization of the putative AFAP1-AS1 promoter region

Actin filament-associated protein 1-antisense RNA1 (AFAP1-AS1), a cancer-related long non-coding RNA, has been found to be upregulated in multiple types of cancers. AFAP1-AS1 is important for the initiation, progression and poor prognosis of many cancers, including nasopharyngeal carcinoma (NPC). However, the mechanism underlying the regulation of AFAP1-AS1 expression is not well-understood. In our study, the potential promoter region of AFAP1-AS1 was predicted by comprehensive bioinformatics analysis. Moreover, promoter deletion analysis identified the sequence between positions -359 and -28 bp as the minimal promoter region of AFAP1-AS1. The ChIP assay results indicate that the AFAP1-AS1 promoter is responsive to the transcription factor c-Myc, which can promote high AFAP1-AS1 expression. This study is the first to clone and characterize the AFAP1-AS1 promoter region. Our findings will help to better understand the underlying mechanism of high AFAP1-AS1 expression in tumorigenesis and to develop new strategies for therapeutic high expression of AFAP1-AS1 in NPC.

AFAP1-AS1 Promotes Epithelial-Mesenchymal Transition and Tumorigenesis Through Wnt/β-Catenin Signaling Pathway in Triple-Negative Breast Cancer

Long non-coding RNA (LncRNA) actin filament-associated protein1-antisense RNA 1 (AFAP1-AS1) is overexpressed in various types of cancers and plays an important role in tumor progression and prognosis. This study investigates the role of AFAP1-AS1 in tumor progression in triple-negative breast cancer (TNBC). We found that AFAP1-AS1 was overexpressed in TNBC tissues and cells. Overexpression of LncRNA AFAP1-AS1 was associated with poor prognosis in TNBC patients. Moreover, we demonstrated that upregulation of AFAP1-AS1 promoted cell proliferation and invasion, and inhibited cell apoptosis in vitro, while overexpression of AFAP1-AS1 promoted tumor growth in vivo. Our results also revealed that upregulation of AFAP1-AS1 activated Wnt/β-catenin pathway to promote tumorigenesis and cell invasion by increasing the expression of C-myc and epithelial-mesenchymal transition-related molecules in TNBC. Collectively, AFAP1-AS1 can be an independent prognostic marker and an effective therapeutic target of triple- negative breast cancer.

Long noncoding RNA AFAP1-AS1 acts as a competing endogenous RNA of miR-423-5p to facilitate nasopharyngeal carcinoma metastasis through regulating the Rho/Rac pathway

BACKGROUND

Actin filament-associated protein 1 antisense RNA 1 (AFAP1-AS1), a long noncoding RNA, is significantly highly expressed and associated with metastasis and poor prognosis in many cancers, including nasopharyngeal carcinoma (NPC). In this study, we aim to identify the role of AFAP1-AS1 acting as an oncogenic lncRNA to promote NPC metastasis.

METHODS

The role of AFAP1-AS1, miR-423-5p, and FOSL2 in NPC metastasis was investigated in vitro and in vivo. Bioinformatics analysis and luciferase activity assays were used to identify the interaction between AFAP1-AS1, miR-423-5p, and FOSL2. Additionally, real-time PCR and western blotting were used to assess the function of AFAP1-AS1 acting as an oncogenic lncRNA to promote NPC progression by regulating miR-423-5p and the downstream Rho/Rac pathway.

RESULTS

In this study, we determined that AFAP1-AS1 functions as a competing endogenous RNA in NPC to regulate the Rho/Rac pathway through miR-423-5p. These interactions can mediate the expression of RAB11B, LASP1, and FOSL2 and accelerate cell migration and invasion via the Rho/Rac signaling pathway or FOSL2. AFAP1-AS1 and FOSL2 could competitively bind with miR-423-5p to regulate several molecules, including RAB11B and LASP1 of the Rho/Rac signaling pathway. AFAP1-AS1 can also regulate the expression of LASP1, which was transcriptionally regulated by FOSL2, resulting in increased migration and invasion of NPC cells via the Rho/Rac signaling pathway.

CONCLUSIONS

The observations in this study identify an important role for AFAP1-AS1 as a competing endogenous RNA (ceRNA) in NPC pathogenesis and indicate that it may serve as a potential target for cancer diagnosis and treatment.

lncRNA AFAP1-AS1 Promotes Migration and Invasion of Non-Small Cell Lung Cancer via Up-Regulating IRF7 and the RIG-I-Like Receptor Signaling Pathway

BACKGROUND/AIMS

Accumulating evidence has highlighted the importance of long non-coding RNAs (lncRNAs) as competing endogenous RNAs (ceRNAs) in tumor biology. Among others, actin filament-associated protein 1 antisense RNA 1 (AFAP1-AS1) has been associated with non-small cell lung cancer (NSCLC). However, it remains unclear how AFAP1-AS1 participates in the development and progression of NSCLC.

METHODS

The peripheral blood samples were collected from patients with NSCLC. White blood cell subsets were classified and levels of interleukin (IL)-10, IL-12 and IFN-γ in serum were measured. We then identified its target gene of AFAP1-AS1 via bioinformatics methods. NSCLC cell line with the highest expression of AFAP1-AS1, i.e. H1975 was selected for in vitro experiments. A series of inhibitor, vector and siRNA were employed to validate the regulatory mechanisms of AFAP1-AS1 in the development and progression of NSCLC. Cell proliferation was detected by MTT assay and EdU staining. Cell migration and invasion, and cell cycle and apoptosis were measured by transwell assay and flow cytometry, respectively.

RESULTS

A high expression of AFAP1-AS1 was identified in NSCLC, alongside with a reduced level of IL-12 and increased levels of IL-10 and interferon (IFN)-γ. Aberrant expressions of AFAP1-AS1 were associated with pathological grade, TNM staging and metastatic potential of NSCLC. AFAP1-AS1 could activate interferon regulatory factor (IRF)7, the retinoid-inducible protein (RIG)-I-like receptor signaling pathway and Bcl-2 in vitro. Over-expression of AFAP1-AS1 promoted NSCLC cell proliferation, invasion and migration while inhibiting cell apoptosis.

CONCLUSION

lncRNA AFAP1-AS1 promotes migration and invasion of non-small cell lung cancer via up-regulating IRF7 and the RIG-I-like receptor signaling pathway.

Expression analysis of AFAP1-AS1 and AFAP1 in breast cancer

Long non-coding RNAs (lncRNA) constitute a significant percentage of RNAs with no translation to proteins. Their participation in fundamental aspects of cell physiology as well as their dysregulation in a number of pathologic conditions such as cancer have been documented. Among lncRNAs is actin filament associated protein 1 antisense RNA1 (AFAP1-AS1) whose elevated expression levels have been demonstrated in different cancers. In the in the present study we evaluated expression levels of AFAP1-AS1 and its antisense protein coding gene AFAP1 in breast cancer samples compare with adjacent non-cancerous tissues (ANCTs) as well as breast cancer cell lines with special focus on the assessment of the association between their transcript levels and patients' clinicopathological data. AFAP1-AS1 has shown significant up-regulation in both MDA-MB-231 and MCF-7 compared with control sample. AFAP1-AS1 has been shown to be expressed in all of tumor tissues but 76% (39 out of 51) ANCTs. AFAP1 expression was not significantly different between tumor samples and ANCTs. AFAP1-AS1 has been demonstrated to be significantly up-regulated in tumor tissues compared with ANCTs (fold change = 4.65, P= 0.028). No significant correlation has been detected between the levels of these two transcripts in tumor tissues (R=2 0.081) or ANCTs (R=2 0.115). No significant associations have been found between expression levels of these genes and patients' characteristics. However, both genes were significantly down-regulated in Ki-67 negative tumor samples. The observed up-regulation of AFAP1-AS1 in tumor samples compared with ANCTs implies its involvement in breast cancer pathogenesis and potentiates it as a biomarker or therapeutic target.

Cucurbitacin B suppresses proliferation of pancreatic cancer cells by ceRNA: Effect of miR-146b-5p and lncRNA-AFAP1-AS1

Cucurbitacin B (CuB) is a natural tetracyclic triterpene product that displays antitumor activity against a wide variety of cancers. In this study, we explored the antipancreatic cancer activity of CuB via the inhibition of expression of the cancer-related long noncoding RNA, actin filament-associated protein 1-antisense RNA 1 (AFAP1-AS1). CuB arrested pancreatic cancer (PC) cells in the G2/M cell cycle phase by suppressing the expression of AFAP1-AS1. Insights into the mechanisms of competing endogenous RNAs (ceRNAs) gained from bioinformatics analysis and luciferase activity assays showed that the epidermal growth factor receptor (EGFR) and AFAP1-AS1 directly compete for miR-146b-5p binding. CuB-induced high miR-146b-5p expression and inhibited the expression of AFAP1-AS1. In summary, reducing the expression of endogenous AFAP1-AS1 effectively increased the available concentration of miR-146b-5p in PC, whereas miR-146b-5p overexpression prevented the expression of endogenous AFAP1-AS1. In particular, we hypothesized that AFAP1-AS1 might act as a ceRNA, effectively becoming a sponge for miR-146b-5p, thereby activating the expression of the EGFR. Thus, CuB suppresses the proliferation, in vitro and in vivo, of PC cells through the ceRNA effect of AFAP1-AS1 on miR-146b-5p.

Long non-coding RNA AFAP1-AS1/miR-320a/RBPJ axis regulates laryngeal carcinoma cell stemness and chemoresistance

AFAP1-AS1 is a long non-coding RNA that is associated with tumorigenesis and poor prognosis in a variety of cancers. We have been suggested that AFAP1-AS1 increases tumorigenesis in laryngeal carcinoma specifically by enhancing stemness and chemoresistance. We assessed AFAP1-AS1 expression in human laryngeal specimens, paired adjacent normal tissues and human HEp-2 cells. Indeed, we found not only that AFAP1-AS1 was up-regulated in laryngeal carcinoma specimens and cells, but also that stemness-associated genes were overexpressed. Silencing of AFAP1-AS1 promoted HEp-2 cell chemoresistance under cisplatin treatment. Expression of AFAP1-AS1 was increased in drug-resistant Hep-2 cells. We then probed the mechanism of AFAP1-AS1 activity and determined that miR-320a was a potential molecular target of AFAP1-AS1. Luciferase reporter and qRT-PCR assays of AFAP1-AS1 and miR-320a levels in human specimens and cell cultures indicated that AFAP1-AS1 negatively regulates miR-320a. To discover the molecular mechanism of miR-320a, we again used the DIANA Tools algorithm to predict its genetic target, RBPJ. After cloning the 3'-untranslated regions (3'-UTR) of RBPJ into a luciferase reporter, we determined that miR-320a did in fact reduce RBPJ mRNA and protein levels. Ultimately, we determined that AFAP1-AS1 increases RBPJ expression by negatively regulating miR-320a and RBPJ overexpression rescues stemness and chemoresistance inhibited by AFAP1-AS1 silencing. Taken together, these results suggest that AFAP1-AS1 can serve as a prognostic biomarker in laryngeal carcinoma and that miR-320a has the potential to improve standard therapeutic approaches to the disease, especially for cases in which cancer cell stemness and drug resistance present significant barriers to effective treatment.

The role of long non-coding RNA AFAP1-AS1 in human malignant tumors

OBJECTIVES

Long non-coding RNAs (lncRNAs) are a type Table of endogenous RNA longer than 200 nucleotides in length, and this kind of RNAs lack or possess limited ability of coding proteins. A large number of studies have demonstrated that lncRNAs could take part in massive biological processes, such as transcriptional activation and interference, cellular differentiation, proliferation, migration, invasion and apoptosis. The abnormal expression of lncRNAs has been clarified to play extremely important roles in various diseases, especially in human cancers. LncRNA actin filament-associated protein 1 antisense RNA 1 (AFAP1-AS1) is a newly recognized cancer-related lncRNA deriving from the antisense strand of DNA at the AFAP1 coding gene locus. A slew of new studies suggest that AFAP1-AS1 is involved in many kinds of malignant tumors. Moreover, in recent years, the dysregulated expression of AFAP1-AS1 has been confirmed to be associated with oncogenesis and tumor progression. Evidence has increasingly shown that AFAP1-AS1 could probably serve as a novel potential molecular biomarker in tumor diagnosis and therapeutic target in tumor treatment. In this review, we sum up present stage new hottest research issues in respect of the biological functions and molecular mechanisms of AFAP1-AS1 in occurrence and progression of human tumors.

MATERIALS AND METHODS

In this review, we summarize the recent researches about the expression and molecular biological mechanisms of lncRNA AFAP1-AS1 in tumor development. Existing relevant studies are acquired and analyzed by searching Pubmed, BioMedNet, GEO database and Academic Search Elit systematically.

RESULTS

Long non-coding RNA AFAP1-AS1 is an important tumor-associated lncRNA and its aberrant expression has been found in many malignancies so far, including pancreatic ductal adenocarcinoma, cholangiocarcinoma, gallbladder cancer, hepatocellular carcinoma, gastric cancer, colorectal cancer, esophageal cancer, nasopharyngeal carcinoma, lung cancer, ovarian cancer, breast cancer, retinoblastoma, laryngeal cancer, tongue squamous cell carcinoma and thyroid cancer. In addition, the dysregulated expression of AFAP1-AS1 is related to carcinogensis, overall survival (OS), disease-free survival (DFS), progression-free survival (PFS) and tumor progression containing lymph node metastasis, distant metastasis, histological grade, tumor size and tumor stage.

CONCLUSIONS

A series of studies provide detailed information to understand lncRNA AFAP1-AS1 role in various human cancers. LncRNA AFAP1-AS1 is an oncogene in tumors that have been studied so far, and it may act as a useful tumor biomarker and therapeutic target.

Up-regulated lncRNA AFAP1-AS1 indicates a poor prognosis and promotes carcinogenesis of breast cancer

BACKGROUND

Long noncoding RNAs (lncRNAs) have been reported to play crucial roles in breast cancer. This study aimed to determine the clinical significance and biological functions of lncRNA AFAP1-AS1 in breast cancer.

METHODS

The expression of AFAP1-AS1 in breast cancer tissue and adjacent normal tissue from 160 patients and breast cancer cell lines were determined by qRT-PCR. The clinical characteristics of patients were collected to analyse the correlation between AFAP1-AS1 expression and malignancy status. Kaplan-Meier and Cox proportional hazards model were used to analyze whether AFAP1-AS1 expression impacted prognosis. To assess the effect of AFAP1-AS1 on MCF-7 cells proliferation, cell viability, EdU incorporation and colony formation assays were conducted after AFAP1-AS1 knockdown by siRNA. The apoptosis was detected by Caspase-3 activity, cell cycle analysis, Bcl-2 and Bax protein expression. Wound scratch assay and EMT-related protein expression (E-cadherin, N-cadherin and Vimentin) were conducted to evaluate the metastasis ability. To further determine the effect of AFAP1-AS1 on AFAP1, the mRNA and protein expression of AFAP1 and subsequent actin filament integrity were measured after AFAP1-AS1 knockdown.

RESULTS

The expression of AFAP1-AS1 was up-regulated in human breast cancer tissue and associated with malignancy status, high expression of AFAP1-AS1 had a poor prognosis in breast cancer patients. AFAP1-AS1 expression was up-regulated in 4 breast cancer cell lines (MCF-7, SK-RB-3, MDA-MB-231and MDA-MB-468) compared with normal breast cell line HBL-100. MCF-7, the most up-regulation cancer cell, was used for following studies. AFAP1-AS1 knockdown can inhibit the proliferation, metastasis and promote apoptosis of MCF-7. However, the AFAP1 expression and actin filament integrity was not affected after AFAP1-AS1 knockdown.

CONCLUSION

Up-regulated lncRNA AFAP1-AS1 indicates a poor prognosis in breast cancer patients and regulated the breast cancer cells proliferation, apoptosis and metastasis.

Long noncoding RNA AFAP1-AS1 predicts a poor prognosis and regulates non-small cell lung cancer cell proliferation by epigenetically repressing p21 expression

BACKGROUND

Mounting evidence indicates that long noncoding RNAs (lncRNAs) could play a pivotal role in cancer biology. However, the role and molecular mechanism and global genes that were mediated by lncRNA AFAP1-AS1 in non-small cell lung cancer (NSCLC) remain largely unknown.

METHODS

Expression of AFAP1-AS1 was analyzed in 92 NSCLC tissues and cell lines by Quantitative real time polymerase chain reaction (qRT-PCR). The effect of AFAP1-AS1 on proliferation was evaluated by function assays both in in vitro and in vivo. RNA-seq assays were performed after knockdown AFAP1-AS1. RNA immunoprecipitation (RIP) was performed to confirm the interaction between AFAP1-AS1 and EZH2. Chromatin immunoprecipitation (ChIP) was used to study the promoter region of p21.

RESULTS

AFAP1-AS1 expression was increased in NSCLC tissues and was correlated with clinical outcomes of NSCLC. Further experiments revealed that inhibition of its expression in NSCLC cells resulted in diminished cell growth in vitro and in vivo. RNA-seq revealed that knockdown of AFAP1-AS1 could induce the expression of p21. Mechanistic investigations found that AFAP1-AS1 could interact with EZH2 and recruit EZH2 to the promoter regions of p21, thus epigenetically repressing p21 expression.

CONCLUSIONS

Together, these results suggest that lncRNA AFAP1-AS1 may serve as a candidate prognostic biomarker and target for new therapies in human NSCLC.

LncRNA AFAP1-AS1 is a prognostic biomarker and serves as oncogenic role in retinoblastoma

The actin filament-associated protein 1 antisense RNA 1 (AFAP1-AS1) has been found to serve as an oncogenic long noncoding RNA (lncRNA) in most types of human cancer. The role of AFAP1-AS1 in retinoblastoma remains unknown. The purpose of the present study is to explore the clinical significance and biological function of AFAP1-AS1 in retinoblastoma. Levels of AFAP1-AS1 expression were measured in retinoblastoma tissues and cell lines. Loss-of-function study was performed to observe the effects of AFAP1-AS1 on retinoblastoma cell proliferation, cell cycle, migration, and invasion. In our results, AFAP1-AS1 expression was elevated in retinoblastoma tissues and cell lines, and associated with tumor size, choroidal invasion, and optic nerve invasion. Moreover, high expression of AFAP1-AS1 was an independent unfavorable prognostic factor in retinoblastoma patients. The experiment in vitro suggested down-regulation of AFAP1-AS1 inhibited retinoblastoma cell proliferation, migration and invasion, and blocked cell cycle. In conclusion, AFAP1-AS1 functions as an oncogenic lncRNA in retinoblastoma.

Long noncoding RNA AFAP1-AS1 facilitates tumor growth through enhancer of zeste homolog 2 in colorectal cancer

Increasing evidences have shown that long noncoding RNAs (lncRNAs) play critical regulatory roles in cancer biology. However, the contributions of lncRNAs to colorectal cancer remain largely unknown. Here, we identify a lncRNA AFAP1-AS1 that facilitates colorectal cancer, where it is upregulated. AFAP1-AS1 expression was associated with colorectal cancer patient survival. AFAP1-AS1 knockdown inhibited cell proliferation, cell cycle, and tumorigenesis in an subcutaneous mouse xenograft model system. Further data demonstrated that AFAP1-AS1 was associated with enhancer of zeste homolog 2 (EZH2) and that this association was required for the repression of EZH2 target genes. Our findings indicate that AFAP1-AS1 is an oncogenic lncRNA that promotes tumor progression and may be a novel prognostic factor in colorectal cancer. Targeting AFAP1-AS1 might be a potential therapeutic strategy for colorectal cancer treatment.

Co-expression of AFAP1-AS1 and PD-1 predicts poor prognosis in nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) carries a high potential for metastasis and immune escape, with a great risk of relapse after primary treatment. Through analysis of whole genome expression profiling data in NPC samples, we found that the expression of a long non-coding RNA (lncRNA), actin filament-associated protein 1 antisense RNA 1 (AFAP1-AS1), is significantly correlated with the immune escape marker programmed death 1 (PD-1). We therefore assessed the expression of AFAP1-AS1 and PD-1 in a cohort of 96 paraffin-embedded NPC samples and confirmed that AFAP1-AS1 and PD-1 are co-expressed in infiltrating lymphocytes in NPC tissue. Moreover, patients with high expression of AFAP1-AS1 or PD-1 in infiltrating lymphocytes were more prone to distant metastasis, and NPC patients with positive expression of both AFAP1-AS1 and PD-1 had the poorest prognosis. This study suggests that AFAP1-AS1 and PD-1 may be potential therapeutic targets in NPC and that patients with co-expression of AFAP1-AS1 and PD-1 may be ideal candidates for future clinical trials of anti-PD-1 immune therapy.

Knockdown of long non-coding RNA AFAP1-AS1 inhibits growth and promotes apoptosis in pituitary adenomas

Recent studies have reported that the long non-coding RNA (lncRNA) AFAP antisense RNA 1 (AFAP1-AS1) is involved in various biological processes and plays a key role in regulating cancer growth and metastasis in humans. However, its effects on tumorigenesis in pituitary adenomas remain unclear. The present study investigated the expression and biological role of AFAP1-AS1 in pituitary adenomas. We observed that the expression of AFAP1-AS1 was considerably higher in the pituitary adenoma tissues as compared to its expression in the adjacent tissues. Additionally, knockdown of AFAP1-AS1 inhibited the proliferation, arrested the cell cycle in the G1-to-S transition phase, and promoted apoptosis in GH3 and MMQ cells. Finally, knockdown of AFAP1-AS1 also promoted the expression of PTEN and inhibited the expression of PI3K and p-AKT. Our results provided novel insights into the function and mechanism of action of AFAP1-AS1 in the pathogenesis of pituitary adenomas.

Upregulation of the long non-coding RNA AFAP1-AS1 affects the proliferation, invasion and survival of tongue squamous cell carcinoma via the Wnt/β-catenin signaling pathway

Background

Long non-coding RNA (lncRNA) actin filament associated protein 1 antisense RNA1 (AFAP1-AS1) is oriented in an antisense direction to the protein-coding gene AFAP1 in the opposite strand. Previous studies showed that lncRNA AFAP1-AS1 was upregulated and acted as an oncogene in a variety of tumors. However, the expression and biological functions of lncRNA AFAP1-AS1 in tongue squamous cell carcinoma (TSCC) are still unknown.

Methods

The expression level of AFAP1-AS1 was measured in 103 pairs of human TSCC tissues and corresponding adjacent normal tongue mucous tissues. The correlation between AFAP1-AS1 and the clinicopathological features was evaluated using the chi-square test. The effects of AFAP1-AS1 on TSCC cells were determined via a CCK-8 assay, clone formation assay, flow cytometry, wound healing assay and transwell assay. Furthermore, the effect of AFAP1-AS1 knockdown on the activation of the Wnt/β-catenin signaling pathway was investigated. Finally, CAL-27 cells with AFAP1-AS1 knockdown were subcutaneously injected into nude mice to evaluate the effect of AFAP1-AS1 on tumor growth in vivo.

Results

In this study, we found that lncRNA AFAP1-AS1 was increased in TSCC tissues and that patients with high AFAP1-AS1 expression had a shorter overall survival. Short hairpin RNA (shRNA)-mediated AFAP1-AS1 knockdown significantly decreased the proliferation of TSCC cells. Furthermore, AFAP1-AS1 silencing partly inhibited cell migration and invasion. Inhibition of AFAP1-AS1 decreased the activity of the Wnt/β-catenin pathway and suppressed the expression of EMT-related genes (SLUG, SNAIL1, VIM, CADN, ZEB1, ZEB2, SMAD2 and TWIST1) in TSCC cells. In addition, CAL-27 cells with AFAP1-AS1 knockdown were injected into nude mice to investigate the effect of AFAP1-AS1 on tumorigenesis in vivo. Downregulation of AFAP1-AS1 suppressed tumor growth and inhibited the expression of EMT-related genes (SLUG, SNIAL1, VIM, ZEB1, NANOG, SMAD2, NESTIN and SOX2) in vivo.

Conclusions

Taken together, our findings present a road map for targeting the newly identified lncRNA AFAP1-AS1 to suppress TSCC progression, and these results elucidate a novel potential therapeutic strategy for TSCC.

Meta-analysis of the prognostic value of long non-coding RNA AFAP1-AS1 for cancer patients in China

LncRNA actin filament-associated protein 1 antisense RNA 1 (AFAP1-AS1) is often dysregulated in cancer. We performed this meta-analysis to clarify the usefulness of AFAP1-AS1 as a prognostic marker in malignant tumors. The PubMed, Medline, OVID, Cochrane Library, and Web of Science databases were searched from inception to Augest 7, 2017. Sixteen studies with a total of 1,386 patients were included in the study. The pooled hazard ratio (HR) suggested high AFAP1-AS1 expression correlated with poor overall survival (OS) (HR = 1.98, 95% confidence interval (CI): 1.71–2.28), disease-free survival (DFS) (HR = 1.54, 95% CI: 1.22–1.95), and progression-free survival (PFS) (HR = 2.17, 95% CI:1.64–2.88) in cancer patients, without obvious heterogeneity. High AFAP1-AS1 expression also correlated with larger tumor size (odds ratio (OR) = 2.04, 95% CI: 1.54–2.72), advanced tumor stage (OR=2.35, 95% CI: 1.70–3.26), poor histological grade (OR =1.39, 95% CI: 1.02–1.90), lymph node metastasis (OR = 2.71, 95% CI: 1.98–3.72) and distant metastasis (OR = 2.96, 95% CI: 2.03–4.32). Thus high AFAP1-AS1 expression is predictive of poor OS, DFS, PFS, lymph node metastasis, distant metastasis, histological grade, larger tumor size and tumor stage, which suggests high AFAP1-AS1 expression may serve as a novel biomarker of poor prognosis in cancer.

Long non-coding RNA AFAP1-AS1 is a novel biomarker in various cancers: a systematic review and meta-analysis based on the literature and GEO datasets

Background

Growing evidence indicates that AFAP1-AS1 plays an important role in various cancers, suggesting that it might be a potential cancer biomarker.

Materials and Methods

A meta-analysis was performed using microarray data obtained via the Affymetrix Human Genome U133 Plus 2.0 platform (found in the GEO database) and data obtained through a systematic search of PubMed and Web of Science. The pooled odds ratio (OR) and hazard ratio (HR) with 95% CI (confidence interval) were used to judge the value of biomarkers.

Results

A total of 30 studies were included in this meta-analysis, comprising a total of 3573 patients. AFAP1-AS1 was significantly linked with overall survival (OS) (HR = 1.58; 95% CI: 1.12–2.23) and recurrence-free survival (RFS) (HR = 2.32, 95% CI: 1.68–3.19). We found that AFAP1-AS1 was a risk factor in the prognoses of lung cancer (pooled HR: 1.54; 95% CI: 1.01–2.34), digestive system cancer (pooled HR: 1.87; 95% CI: 1.45–2.41) and nasopharyngeal carcinoma (HR: 11.82; 95% CI: 5.09–27.46). AFAP1-AS1 was also a risk factor for RFS in breast cancer (pooled HR = 2.90; 95% CI: 1.69–4.98), as well as TNM stage in both esophageal cancer (pooled OR = 1.90; 95% CI: 1.01–3.57) and colorectal cancer (OR = 6.72; 95% CI: 1.92–23.58). AFAP1-AS1 was significantly associated with lymph node metastasis in clear cell carcinoma (OR = 5.04; 95% CI: 2.36–10.78) and distant metastasis in pancreatic cancer (OR = 11.64; 95% CI: 2.13–63.78).

Conclusions

AFAP1-AS1 can serve as a novel molecular marker predicting tumor progression, patient prognosis and lymph node metastasis in different types of cancers.

Silencing of lncRNA AFAP1-AS1 suppressed lung cancer development by regulatory mechanism in cis and trans

Although the long noncoding RNA AFAP1-AS1 has been shown to be involved in various types of cancer, its involvement in lung cancer remains poorly understood. In the current study, we found that AFAP1-AS1 was substantially over expressed in lung cancer tissues and cell lines. In addition, AFAP1-AS1 expression level was proven to be associated with the malignant features of lung cancer. Knockdown of AFAP1-AS1 significantly suppressed cell proliferation by increasing cell apoptosis and G0/G1 phase retardation of cell cycle in lung cancer cells. Furthermore, AFAP1-AS1 knockdown could suppress tumor growth of lung cancer in BALB/c nude mice. We also identified that AFAP1-AS1 silencing could influence the expression of AFAP1 and KRT1 on mRNA and protein level by cis and trans regulatory mechanism. Moreover, the oncogenic activities of AFAP1-AS1 on cell proliferation are partially mediated by KRT1. In summary, these findings demonstrate that AFAP1-AS1 plays an essential role in promoting lung cancer development in vitro and vivo. It indicated that AFAP1-AS1 is a promising prognostic predictor for patients with lung cancer.

Long Noncoding RNA AFAP1-AS1 Promotes Cell Proliferation and Apoptosis of Gastric Cancer Cells via PTEN/p-AKT Pathway

BACKGROUND

Long noncoding RNA (lncRNA) plays critical roles in both tumor-suppressive and oncogenic pathways in the pathological development and prognosis of cancers.

AIMS

This study aimed to explore the expression of lncRNA AFAP1-AS1 and its function in gastric cancer (GC).

METHODS

The expression of AFAP1-AS1 was detected in GC tissues and GC cells by quantitative real-time reverse-transcription PCR. A small interfering RNA (siRNA) that targeted AFAP1-AS1 was transfected into cells to inhibit the expression of AFAP1-AS1. MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay and colony formation assay were performed to examine the cell proliferation of SGC7901 cell transfected with si-AFAP1-AS1. Cell apoptosis was detected by flow cytometry. The protein level of cleaved PARP, Caspase 3, Caspase 9, Caspase 8, Bcl-2, Bax, p-AKT, total-AKT, and PTEN were detected by Western blot.

RESULTS

AFAP1-AS1 was up-regulated in GC tissues and GC cells. AFAP1-AS1 knockdown suppressed cell viability of SGC7901 transfected with si-AFAP1-AS1. The number of apoptotic SGC7901 cell transfected with si-AFAP1-AS1 was increased by 3.4-fold comparing to that of control. The protein level of cleaved PARP, Caspase 3, and Caspase 9 were increased in SGC7901 transfected with si-AFAP1-AS1, as well as the expression of Bax. The protein level of Bcl-2 was decreased. AFAP1-AS1 knockdown decreased the protein level of p-AKT and increased the expression of PTEN in SGC7901 cells.

CONCLUSIONS

AFAP1-AS1 was up-regulated in GC cells and regulated the gastric cancer cell proliferation and apoptosis via PTEN/p-AKT pathway.

Down-regulation of long non-coding RNA AFAP1-AS1 inhibits tumor cell growth and invasion in lung adenocarcinoma

An increasing number of deregulated long non-coding RNAs (lncRNA) have been implicated in cancer in humans, suggesting that lncRNAs may be involved in tumorigenesis or tumor progression. In previous investigations, lncRNA, AFAP1-AS1 has been found to be associated with several cancers, including nasopharyngeal carcinoma, lung cancer and esophageal adenocarcinoma. However, the function of AFAP1-AS1 in lung cancer has not been reported. In our present study, we found that AFAP1-AS1 was overexpressed in lung adenocarcinoma and associated with survival time. The low expression of AFAP1-AS1 was an independent predictor for disease-free survival in patients with lung adenocarcinoma. Additionally, we transfected AFAP1-AS1 siRNA into H1975 and HCC827, both lung adenocarcinoma cancer cells, and found that cell growth was suppressed, apoptosis induced and invasion inhibited. Taken together, AFAP1-AS1 down-regulation exerts growth suppression and apoptosis induction in lung adenocarcinoma cells, suggested it may participate in turmorigenesis and be a therapeutic target for treating lung adenocarcinoma in future.

Long Noncoding RNA AFAP1-AS1 Promoted Tumor Growth and Invasion in Cholangiocarcinoma

BACKGROUND

Long non-coding RNAs (lncRNAs) have been shown to play important roles in a wide range of pathophysiological processes, including cancer progression. Our previous study has shown that AFAP1-AS1 was upregulated and acted as an oncogene in hepatocellular carcinoma. However, the expression and biological functions of lncRNA AFAP1-AS1 in intrahepatic cholangiocarcinoma (CCA) remains largely unknown.

METHODS

The expression level of AFAP1-AS1 was measured in 56 pairs of human cholangiocarcinoma tumor tissues and corresponding adjacent normal bile duct tissues. The correlation between AFAP1-AS1 and the clinicopathological features were evaluated by chi-square test. The effects of AFAP1-AS1 on CCA cells were determined by CCK-8 assay, clone formation assay, flow cytometry and transwell assay. Finally, to determine the effect of AFAP1-AS1 on tumor growth in vivo, AFAP1-AS1 knockdowned CCLP-1 cells were subcutaneously into nude mice to evaluate tumor growth.

RESULTS

In this study, we found that lncRNA AFAP1-AS1 was increased in CCA tissues and patients with high AFAP1-AS1 expression had a shorter overall survival. SiRNA-mediated AFAP1-AS1 knockdown significantly decreased cell proliferation of the CCA cells, with downregulation of C-myc and Cycling D1 in vitro. Furthermore, AFAP1-AS1 silencing inhibited cell migration partly due to decrease the expression of MMP-2 and MMP-9. In addition, CCLP-1 cells with AFAP1-AS1 knockdown were injected into nude mice to investigate the effect of AFAP1-AS1 on the tumorigenesis in vivo.

CONCLUSIONS

Taken together, our findings suggested that AFAP1-AS1 might promote the CCA progression and provided a novel potential therapeutic target for CCA.

LncRNA AFAP1-AS1 promotes growth and metastasis of cholangiocarcinoma cells

We investigated the role of actin filament associated protein 1 antisense RNA1 (AFAP1-AS1) lncRNA in promoting cholangiocarcinoma (CCA). qRT-PCR analysis of patient samples showed that AFAP1-AS1 expression was higher in CCA tumors than matched adjacent non-tumor tissue. AFAP1-AS1 levels were also higher in CCA cell lines (HuCCT1 and TFK-1) than a normal biliary epithelium cell line (HIBEpic). AFAP1-AS1 knockdown in CCA cell lines using shAFAP1-AS1 reduced cell proliferation and colony formation in CCK-8 and colony formation assays, respectively. Cell cycle analysis demonstrated that AFAP1-AS1 knockdown resulted in G0/G1 cell cycle arrest and inhibition of S-G2/M transition compared to the controls. CCA cells transfected with shAFAP1-AS1 also exhibited reduced metastasis and invasiveness in Transwell and wound healing assays. This was further confirmed in xenograft experiments with nude mice using CCA cells transfected with shAFAP1-AS1 or control shRNA. AFAP1-AS1 knockdown cells produced smaller tumors, demonstrating that AFAP1-AS1 promotes tumor growth in vivo. AFAP1-AS1 knockdown also increased expression of actin filament associated protein 1 (AFAP1) and reduced cell stress filament integrity, as determined from western blot and immunofluorescence assays, respectively. These findings indicate that AFAP1-AS1 exerts oncogenic effects in CCA. We postulate that AFAP1-AS1 is a potentially useful diagnostic and prognostic biomarker and therapeutic target for CCA.

Long non-coding RNA AFAP1-AS1 facilitates tumor growth and promotes metastasis in colorectal cancer

BACKGROUND AND OBJECTIVE

Long non-coding RNAs can regulate tumorigenesis of various cancers. Dys-regulation of lncRNA-AFAP1-AS1 has not been studied in colorectal carcinoma (CRC). This study was to examine the function involvement of AFAP1-AS1 in tumor growth and metastasis of CRC.

METHODS

Relative expression of AFAP1-AS1 in CRC tissues and CRC cells lines was determined using quantitative real-time PCR (qRT-PCR). Functional involvement of AFAP1-AS1 in tumor proliferation and metastasis was evaluated in AFAP1-AS1-specific siRNA-treated CRC cells and in CRC cell xenograft. Expression of epithelial-mesenchymal transition (EMT)-related gene expression was determined using western blot.

RESULTS

Relative expression of AFAP1-AS1 was significantly elevated in CRC tissues and CRC HCT116 and SW480 cell lines. AFAP1-AS1 knock-down suppressed SW480 cell proliferation, colony formation, migration and invasion. Also AFAP1-AS1 knock-down inhibited tumor metastasis-associated genes expression in terms of EMT. This carcinostatic action by AFAP1-AS1 knock-down was further confirmed by suppression of tumor formation and hepatic metastasis of CRC cells in nude mice.

CONCLUSION

lncRNA-AFAP1-AS1 knock-down exhibits antitumor effect on colorectal carcinoma in respects of suppression of cell proliferation and metastasis of cancer cells.

AFAP1-AS1 is upregulated and promotes esophageal squamous cell carcinoma cell proliferation and inhibits cell apoptosis

Recent findings indicate that long noncoding RNAs (lncRNAs) were dysregulated in many kinds of tumors including esophageal squamous cell carcinoma (ESCC). LncRNA AFAP1-AS1 was found to be upregulated in hepatocellular carcinoma (HCC), lung cancer, colorectal cancer, esophageal adenocarcinoma (EAC), pancreatic ductal adenocarcinoma, and nasopharyngeal carcinoma, while its clinical value and potential function in ESCC are still unknown. Expression of AFAP1-AS1 was measured in 65 ESCC tissues and corresponding noncancerous tissues by quantitative real-time polymerase chain reaction, which revealed that AFAP1-AS1 expression was markedly elevated in ESCC tissues and significantly associated with advanced TNM stage (P = 0.004) and larger tumor size (P = 0.040). Moreover, by knocking down AFAP1-AS1 expression in ESCC cells, the proliferation and colony-forming ability were inhibited and cell apoptosis was induced. Our data indicated the first time that AFAP1-AS1, a novel oncogene, was remarkably upregulated and played a critical role in the progression of ESCC.