Actin Filament Associated Protein 1 Antisense RNA1 Knockdown Research Articles

The lncRNA AFAP1-AS1 is upregulated in metastatic triple-negative breast tumors and controls hypoxia-activated vasculogenic mimicry and angiogenesis

BackgroundVasculogenic mimicry (VM) is an alternative intratumoral microcirculation system that depends on the capacity of tumor cells to reorganize and grow in three-dimensional (3D) channel architectures like the capillaries formed by endothelial cells. Both VM and angiogenesis may coordinately function to feed cancer cells, allowing tumor growth. Long noncoding RNAs (lncRNAs) regulate critical cellular functions in cancer cells, including cell proliferation, apoptosis, angiogenesis, invasion, and metastasis. The lncRNA, known as actin filament-associated protein 1-antisense RNA 1 (AFAP1-AS1), has been described as an oncogene in diverse types of cancers. However, its role in VM and metastasis in triple-negative breast cancer (TNBC) is unknown.MethodsReverse transcription and quantitative polymerase chain reaction (RT‒qPCR) experiments were performed to evaluate the expression of 10 selected lncRNAs from literature in metastatic and nonmetastatic biopsies from TNBC patients. The expression of AFAP1-AS1 was analyzed in Genotype-Tissue Expression Genotype-Tissue Expression (GTEx) and The Cancer Genome Atlas (TCGA) datasets. The AFAP1-AS1 expression was knocked in TNBC Hs578T cells by transfection of specific siRNAs. Channel-like formation assays were performed using 3D cultures over Matrigel in hypoxia-treated Hs578T cancer cells with diminished expression of AFAP1-AS1. The angiogenesis tests were conducted using human umbilical vein endothelial cells (HUVECs) and AFAP1-AS1- silenced Hs578T cells on 3D cell cultures. The presence of VM (CD31-/PAS+) in tumor tissues from TNBC patients with and without metastasis was assessed through immunohistochemistry using endothelial marker CD31 antibodies and periodic acid-Schiff (PAS) staining.ResultsCompared with normal mammary tissues, AFAP1-AS1 expression was higher in breast cancer tissues. Moreover, AFAP1-AS1 expression was upregulated in the TNBC subtype compared to receptor-positive breast tumors. In addition, the expression of AFAP1-AS1 was correlated with the expression of the thirteen genes characteristic of a previously reported hypoxia signature. Interestingly, AFAP1-AS1 was upregulated in primary TNBC tumors from patients who developed metastasis compared with the nonmetastatic group. Functional analysis revealed that the knockdown of AFAP1-AS1 in Hs578T cells significantly impaired the hypoxia-induced VM, accompanied by a decrease in the development of 3D channel networks. Similarly, AFAP1-AS1 knockdown counteracts the angiogenic potential of cancer cells, as indicated by a reduction in the number of polygons, sprouting cells, and nodes in HUVEC cells. Remarkably, an increase in CD31-/PAS + staining of 3D channel networks in primary breast tumors from metastatic patients was found compared with the nonmetastatic group. Finally, we found that the number of blood vessels increased in the nonmetastatic group more than in the metastatic cohort.ConclusionsOur data suggested that AFAP1-AS1 controls both VM and angiogenesis in Hs578T breast cancer cells and that increased metastasis is associated with VM in TNBC patients.

Regulations of Exosomal-Transmitted AFAP1-AS1 LncRNA on Ovarian Cancer Cell Migration and Invasion.

Adolescent ovarian cancer (OC) has high malignancy. Long non-coding RNAs (lncRNAs) have been implicated in the pathogenesis of various malignancies, but their role in adolescent OC remains poorly understood. This study aims to assess the modulatory role of Exosome-transmitted lncRNA Actin filament-associated protein 1 Antisense RNA 1 (AFAP1-AS1) on the activity of OC cells. We recruited a cohort of 40 adolescent patients diagnosed with OC and a control group of 40 healthy individuals. Serum samples were collected from both groups prior surgical intervention. Exosomes from peripheral blood and ascites were collected via differential centrifugation. The expression levels of AFAP1-AS1 in OC tissues and cell lines (IOSE-80, CAOV3, and SKOV3) were quantified using quantitative reverse-transcription polymerase chain reaction (qRT-PCR). The exosomal particle size and surface markers were characterized through nanoparticle tracking analysis and transmission electron microscopy. Furthermore, siRNA-mediated knockdown of AFAP1-AS1 was performed in IOSE-80, CAOV3, and SKOV3 cell lines. Functional assays, including wound-healing experiments and Transwell migration assays, were conducted to evaluate cellular migration and metastasis. Our findings demonstrate that the expression of AFAP1-AS1 is significantly upregulated in OC patients' serum exosomes and ascitic fluid, correlating with unfavorable pathological features such as advanced federation international of gynecology and obstetrics (FIGO) stage and larger tumor diameter. In-vitro experiments revealed that OC cell lines and primary human OC cells showed enhanced proliferation and metastasis when exposed to ascites-derived exosomes enriched in AFAP1-AS1. Importantly, we observed that AFAP1-AS1 can be transmitted to neighboring cells via exosomal pathways. Additionally, exosomes isolated from ascites treated with siRNA targeting AFAP1-AS1 can inhibit cellular migration and invasion. Our data provide evidence for the oncogenic role of AFAP1-AS1, which is transmitted via exosomes. This finding has significant implications for understanding the molecular mechanisms of AFAP1-AS1 in the pathogenesis of adolescent ovarian cancer.

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

Long non-coding RNA 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 quantitative real-time polymerase chain reaction 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.

LncRNA AFAP1-AS1/miR-27b-3p/VEGF-C axis modulates stemness characteristics in cervical cancer cells.

Background:Long non-coding RNA (lncRNA) actin filament-associated protein 1 antisense RNA 1 (AFAP1-AS1) functions as a competing endogenous RNA to regulate target genes expression by sponging microRNAs (miRs) to play cancer-promoting roles in cancer stem cells. However, the regulatory mechanism of AFAP1-AS1 in cervical cancer (CC) stem cells is unknown. The present study aimed to provide a new therapeutic target for the clinical treatment of CC.Methods:Hyaluronic acid receptor cluster of differentiation 44 variant exon 6 (CD44v6)(+) CC cells were isolated by flow cytometry (FCM). Small interfering RNAs of AFAP1-AS1 (siAFAP1-AS1) were transfected into the (CD44v6)(+) cells. The levels of AFAP1-AS1 were measured by quantitative real-time PCR (qRT-PCR). Sphere formation assay, cell cycle analysis, and Western blotting were used to detect the effect of siAFAP1-AS1. RNA pull-down and luciferase reporter assay were used to verify the relationship between miR-27b-3p and AFAP1-AS1 or vascular endothelial growth factor (VEGF)-C.Results:CD44v6(+) CC cells had remarkable stemness and a high level of AFAP1-AS1. However, AFAP1-AS1 knockdown with siAFAP1-AS1 suppressed the cell cycle transition of G(1)/S phase and inhibited self-renewal of CD44v6(+) CC cells, the levels of the stemness markers octamer-binding transcription factor 4 (OCT4), osteopontin (OPN), and cluster of differentiation 133 (CD133), and the epithelial-mesenchymal transition (EMT)-related proteins Twist1, matrix metalloprotease (MMP)-9, and VEGF-C. In the mechanism study, miR-27b-3p/VEGF-C signaling was demonstrated to be a key downstream of AFAP1-AS1 in the CD44v6(+) CC cells.Conclusions:LncRNA AFAP1-AS1 knockdown inhibits the CC cell stemness by upregulating miR-27b-3p to suppress VEGF-C.

Involvement of the lncRNA AFAP1-AS1/microRNA-195/E2F3 axis in proliferation and migration of enteric neural crest stem cells of Hirschsprung's disease.

What is the central question of this study? Long non-coding RNAs (lncRNAs) are widely involved in the progression of Hirschsprung's disease (HSCR), but the role of actin filament associated protein1 antisense RNA1 (AFAP1-AS1), an lncRNA, in HSCR has not been explored before. What is the main finding and its importance? Downregulation of AFAP1-AS1 blocks enteric neural crest stem cell proliferation, differentiation, migration and invasion and promotes the occurrence of HSCR via the miR-195/E2F3 axis, indicating thatAFAP1-AS might be a potential biomarker for HSCR patients. Long non-coding RNAs (lncRNAs) are involved in several human disorders. Nevertheless, it remains unclear whether they are implicated in the phenotypes of enteric neural crest stem cells (ENCSCs) in Hirschsprung's disease (HSCR). Therefore, we designed this study to explore the pathogenicity of AFAP1-AS1 for HSCR. Microarray analysis and bioinformatic tools were used to screen out the differentially lncRNAs and microRNAs (miRNAs) in patients with HSCR. Small interference RNA transfection was applied to carry out functional experiments in ENCSCs. Cellular activities were detected by cell counting kit-8, 5-ethynyl-2'-deoxyuridine, Transwell assays and flow cytometry. Finally, rescue experiments were performed to examine the cofunction of AFAP1-AS1 and miR-195 and of miR-195 and E2F transcription factor 3 (E2F3). AFAP1-AS1 was reduced in HSCR patients. Meanwhile, knockdown of AFAP1-AS1 reduced the cell migratory and proliferative capacities and facilitated cell apoptosis along with G0/G1 phase arrest. E2F3 was diminished when miR-195 was upregulated, and AFAP1-AS1 inhibition reduced its ability to bind to miR-195. Altogether, AFAP1-AS1 silencing acts as an endogenous RNA by interacting with miR-195 to alter E2F3 expression, thus conferring repressive effects on ENCSC activity and promoting HSCR progression.

LncRNA AFAP1-AS1 Knockdown Represses Cell Proliferation, Migration, and Induced Apoptosis in Breast Cancer by Downregulating SEPT2 Via Sponging miR-497-5p.

Background: Long non-coding RNA actin filament-associated protein1-antisense RNA 1 (AFAP1-AS1) was confirmed to be associated with tumorigenesis. However, the role of AFAP1-AS1 in breast cancer was little known. Materials and Methods: Quantitative real-time polymerase chain reaction (qRT-PCR) was used to detect the levels of AFAP1-AS1, microRNA-497-5p (miR-497-5p), and Septin 2 (SEPT2) in breast cancer tissues and cells. The cell proliferation, migration, and apoptosis were tested by Methylthiazolyldiphenyl-tetrazolium bromide (MTT), Transwell and Flow cytometry assays, respectively. The targeting relationship between genes was predicted by StarBase v.3.0 and confirmed by dual-luciferase reporter assay. Pearson's correlation coefficient was applied to examine the correlation between the two groups. SEPT2 protein expression was evaluated by Western blot. Xenograft models were established to investigate the role of AFAP1-AS1 knockdown in vivo. Results: AFAP1-AS1 was upregulated in breast cancer tissues and cells, and AFAP1-AS1 knockdown could hinder proliferation and migration of breast cancer cells, and contribute to cell apoptosis. MiR-497-5p, which was downregulated in breast cancer, was verified to be a target of AFAP1-AS1 and inversely correlated with AFAP1-AS1 expression. SEPT2, as a target gene of miR-497-5p, was negatively regulated by miR-497-5p and positively correlated with AFAP1-AS1 expression. Importantly, AFAP1-AS1 could upregulate SEPT2 expression by sponging miR-497-5p, and modulate cell progression by regulation of the miR-497-5p/SEPT2 axis in breast cancer. Conclusion: AFAP1-AS1 knockdown repressed the progression of breast cancer cells by sponging miR-497-5p and downregulating SEPT2.

Knockdown of Long Non-Coding RNA AFAP1-AS1 Promoted Viability and Suppressed Death of Cardiomyocytes in Response to I/R In Vitro and In Vivo.

Long non-coding RNA (lncRNA) plays a pivotal role in the development of myocardial infarction (MI). The aim of this study was to investigate the effects of lncRNA actin filament-associated protein 1 antisense RNA 1 (AFAP1-AS1) on cell cycle, proliferation, and apoptosis. RT-qPCR was used to detect the expression levels of AFAP1-AS1, miR-512-3p, and reticulon 3 (RTN3) in rat model of I/R. The simulated MI environment was constructed. MTT assay and flow cytometry were used to detect changes in cardiomyocyte viability and cell cycle/apoptosis after MI by AFAP1-AS1 silencing or RTN3 silencing. The targeting relationship of miR-512-3p and AFAP1-AS1 and RTN3 in cardiomyocytes was verified by dual luciferase reporter assay. The expression levels of AFAP1-AS1 and RTN3 were significantly upregulated in a rat model of LAD ligation (or MI) ligation, while the expression level of miR-512-3p was significantly reduced. Overexpressed AFAP1-AS1 and RTN3 promoted cardiomyocyte apoptosis and inhibited cardiomyocyte proliferation. MiR-512-3p was a direct target of AFAP1-AS1, and RTN3 was a direct target of miR-512-3p. AFAP1-AS1 promoted the progression of MI by targeting miR-512-3p. AFAP1-AS1 promoted the progression of MI by modulating the miR-512-3p/RTN3 axis. AFAP1-AS1 may be a potential therapy target for MI. Graphical Abstract The role of AFAP1-AS1 in regulating MI injury in vivo. (A) Effect of AFAP1-AS1 in MI injury in vivo. (B) The mRNA level of RTN3 in MI injury in vivo. (C) The protein level of RTN3 in MI injury in vivo. (D) Effect of miR-512-3p in MI model group. (E) TUNEL assay. *P < 0.05, **P < 0.01 vs the sham group; #P< 0.05, ##P < 0.01 vs the MI group.

Bidirectional interaction of lncRNA AFAP1-AS1 and CRKL accelerates the proliferative and metastatic abilities of hepatocarcinoma cells

Actin filament-associated protein 1 antisense RNA 1 (AFAP1-AS1), a long non-coding RNA transcribed from the antisense strand of protein coding gene AFAP1, has attracted attention in cancer research. Despite, its biological function and regulatory mechanism in hepatocellular carcinoma still unknown. The present study revealed AFAP1-AS1 mediated hepatocarcinoma progression through targeting CRKL. The bidirectional interaction of AFAP1-AS1 and oncogenic protein CRKL, and the deregulation of AFAP1-AS1 effects on Ras, MEK and c-Jun activities were investigated in depth. AFAP1-AS1 was upregulated in surgical tumorous tissues from hepatocarcinoma patients compared with the paired paracancerous non-tumor liver tissues, and in hepatocarcinoma Huh7, HCCLM3 and HepG2 cell lines compared with LO2, a normal liver cell line. AFAP1-AS1 knockdown noticeably suppressed the proliferative, migratory and invasive properties, and the epithelial-mesenchymal transition (EMT) process of HepG2 and HCCLM3 through upregulating E-cadherin and downregulating N-cadherin and vimentin. CRKL knockdown reduced AFAP1-AS1 expression levels in HepG2 and HCCLM3 cells. AFAP1-AS1 suppression impaired CRKL expression in HepG2 and HCCLM3. AFAP1-AS1 level change was positively correlated with the expression level changes of Ras, MEK and c-Jun in mediating the invasiveness of hepatocarcinoma cells. Current work demonstrated AFAP1-AS1 to be an applicable progression indicator of hepatocarcinoma. AFAP1-AS1 probably promotes the proliferation, EMT progression and metastasis of hepatocarcinoma cells via CRKL mediated Ras/MEK/c-Jun and cadherin/vimentin signaling pathways. AFAP1-AS1-CRKL bidirectional feedback signaling is worthy of further study on the monitoring, diagnosis and treatment of cancers.

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

BackgroundAlthough 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.MethodsLncRNA 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.ResultsAFAP1-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.ConclusionExosomal 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.

Long Noncoding RNA AFAP1-AS1 Promotes Cell Proliferation and Metastasis via the miR-155-5p/FGF7 Axis and Predicts Poor Prognosis in Gastric Cancer.

Background Actin filament-associated protein 1-antisense RNA 1 (AFAP1-AS1) plays an important role in the development and progression of several human cancers. However, its biological function in gastric cancer (GC) progression is still unknown. Methods We used qRT-PCR to detect the relative expression of AFAP1-AS1 in GC tissues and cell lines. The loss-of-function assays were conducted to detect the effect of AFAP1-AS1 on GC development. Bioinformatics analysis, luciferase reporter gene analysis, and RIP analysis were used to identify and validate target genes of AFAP1-AS1. Finally, rescue tests were performed to confirm the influence of the AFAP1-AS1-miR-155-5p-FGF7 axis on GC development. Results AFAP1-AS1 was upregulated in GC tissues and cell lines and was closely correlated with poor prognosis of GC patients. AFAP1-AS1 knockdown inhibited proliferation, migration, and invasion of GC cells, indicating that AFAP1-AS1 acts as an oncogene in GC. Bioinformatics analysis, dual-luciferase reporter gene detection, and RIP assays validated that AFAP1-AS1 directly interacts to miR-155-5p and could positively affect cell proliferation, migration, and invasion by regulation of the expression of miR-155-5p and FGF7. Further rescue assays revealed that AFAP1-AS1 promotes cell proliferation and metastasis through the miR-155-5p/FGF7 axis in GC. Conclusions AFAP1-AS1 might be an oncogenic lncRNA that promoted GC progression by acting as a competing endogenous RNA (ceRNA) that regulates the expression of FGF7 through sponging miR-155-5p, suggesting that AFAP1-AS1 may be a novel potential therapeutic target for GC.

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

AimDegenerative 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. MethodsAFAP1-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. ResultsAFAP1-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. ConclusionCollectively, 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.

Long non-coding RNA AFAP1-AS1 promotes proliferation and migration of gastric cancer by downregulating KLF2.

To clarify the function of actin filament associated protein 1-antisense RNA1 (AFAP1-AS1) to promote the proliferation and migration of gastric cancer (GC) cells by downregulating Krüppel-like factor 2 (KLF2). Expression level of AFAP1-AS1 in GC tissues and matched paracancerous tissues was determined by quantitative real-time polymerase chain reaction (qRT-PCR). Besides, its level in GC either with lymphatic metastasis or not, and those in different tumor stages were determined as well. Regulatory roles of AFAP1-AS1 in cellular behaviors of GC cells were evaluated by functional experiments. The ability of AFAP1-AS1 to recruit EZH2 was evaluated through chromatin immunoprecipitation (ChIP) assay. The expression level of KLF2 in GC cells influenced by AFAP1-AS1 and EZH2 was detected by Western blot. Finally, a series of rescue experiments were conducted to clarify the role of AFAP-AS1/KLF2 in GC cell performances. AFAP1-AS1 was upregulated in GC tissues, and its expression in lymph node metastasis and progressive gastric cancer tissues were much higher. Knockdown of AFAP1-AS1 reduced the viability, proliferative and migratory abilities, but induced apoptosis of GC cells. AFAP1-AS1 was verified to bind to EZH2. After knockdown of AFAP1-AS1, the ability of AFAP1-AS1 to recruit EZH2 was remarkably attenuated. Knockdown of AFAP1-AS1 or EZH2 upregulated KLF2 expression in GC cells. Notably, knockdown of KLF2 partially reversed the effect of AFAP1-AS1 on GC cell performances. LncRNA AFAP1-AS1 accelerates the proliferative and migratory abilities of GC cells by downregulating the expression of KLF2, thus promoting the progression of GC.

Expression and functions of long non-coding RNA actin filament-associated protein 1-antisense RNA1 in oral squamous cell carcinoma

To analyze the expression and clinical significance of long non-coding RNA (lncRNA) actin filament-associated protein 1-antisense RNA1 (AFAP1-AS1) in oral squamous cell carcinoma (OSCC) and its effect on the biobehavior of OSCC cells. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to detect the expression of lncRNA AFAP1-AS1 in the tumor tissue and matching adjacent normal tissue of OSCC patients (n=55), SCC25 cells, and normal oral keratinocyte lines (NOK) cells. The correlation between AFAP1-AS1 expression and the clinicopathological characteristics of OSCC patients was analyzed. The relationship between AFAP1-AS1 and prognosis was also studied with the Kaplan-Meier method. AFAP1-AS1 siRNA was transfected into the SCC25 cells. Cell counting kit-8 (CCK-8) and Trans-well were used to detect cell proliferation, invasion, and migration. The expression of the invasion-associated protein, AFAP1, and Rho GTPase family members, was detected by Western blot. In addition, the immunofluorescence of the cytoskeletal actin filament was observed. The expression of AFAP1-AS1 was higher in the OSCC tissues than in the NOK cells, and the relative expression of AFAP1-AS1 was higher in the SCC25 cells than in the NOK cells (P<0.001). AFAP1-AS1 expression was associated with the degree of diffe-rentiation, TNM stage, lymphatic metastasis, and poor prognosis of OSCC (P<0.05). Patients with a high expression of AFAP1-AS1 had lower survival rates than those with a low expression of AFAP1-AS1 (P<0.05). After transfected by AFAP1-AS1 siRNA, the expression of AFAP1-AS1 was downregulated. The inhibition of AFAP1-AS1 expression consequently suppressed the proliferation, invasion, and migration of SCC25. Moreover, AFAP1-AS1 siRNA upregulated the expression levels of AFAP1, RhoA, Rac2, Rab10, RhoGDI, and Pfn1 but downregulated the expression of RhoC. Immunofluorescence showed that AFAP1-AS1 also reduced the formation of stress filaments in the cytoskeleton and affected the integrity of the actin fila-ment. The expression of AFAP1-AS1 was high in the OSCC tissues and SCC25 cells and is associated with the development and prognosis of OSCC. The knockdown of AFAP1-AS1 might inhibit the proliferation and invasion of OSCC cells by regulating the integrity of the actin filament.

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.

Overexpression of lncRNA AFAP1-AS1 promotes cell proliferation and invasion in gastric cancer.

Long non-coding RNA (lncRNA) actin filament-associated protein 1 antisense RNA 1 (AFAP1-AS1) has been revealed to be associated with certain types of cancer. However, whether the lncRNA AFAP1-AS1 is involved in the development and progression of gastric cancer (GC) remains unknown. The present study investigated the clinical significance and biological functions of AFAP1-AS1 in GC. The expression levels of lncRNA AFAP1-AS1 in 52 patients with GC, and in 1 normal gastric mucosal cell line and 3 GC cell lines, were evaluated by reverse transcription quantitative polymerase chain reaction analysis. Small interfering RNAs were used to suppress AFAP1-AS1 expression in GC cell lines. The results indicated that AFAP1-AS1 expression levels were significantly increased in GC tissues and cell lines compared with the corresponding noncancerous tissues and normal gastric cells. In addition, the patients with GC with increased AFAP1-AS1 expression exhibited an advanced clinical stage and an association with the occurrence of lymph node metastasis compared with those with decreased AFAP1-AS1 expression. In vitro assays demonstrated that knockdown of AFAP1-AS1 decreased levels of cell proliferation and migration. In addition, the results of flow cytometry demonstrated that knockdown of AFAP1-AS1 caused cell cycle arrest. In conclusion, AFAP1-AS1 is a novel molecule involved in GC progression, which may be a potential prognostic biomarker and target for therapeutic intervention.

Cross-talk among AFAP1-AS1, ACVR1 and microRNA-384 regulates the stemness of pancreatic cancer cells and tumorigenicity in nude mice

BackgroundPancreatic cancer (PC) represents one of the most aggressive forms of cancer. The role of long non-coding RNAs (lncRNAs) has been highlighted in various malignancies including PC. The aim of the present study was to investigate the effects associated with actin filament-associated protein 1 antisense RNA 1 (AFAP1-AS1) on the progression of PC and the underlying mechanism.MethodsMicroarray-based gene expression profiling of PC was performed to identify PC-related lncRNAs, after which the expression of AFAP1-AS1 and cancer stem cell (CSC) markers in PC tissues and cells were determined accordingly. The potential microRNA-384 (miR-384) capable of binding to AFAP1-AS1, in addition to its ability to regulate activin receptor A type I (ACVR1) were analyzed. In order to investigate the effect of the AFAP1-AS1/miR-384/ACVR1 axis on self-renewal ability, tumorigenicity, invasion, migration and stemness of PC cells, shRNA-AFAP1-AS1, miR-384 mimic and inhibitor were cloned into cells.ResultsHigh expression of AFAP1-AS1 and ACVR1 with low expression of miR-384 were detected in PC tissues. ACVR1 was determined to be down-regulated when miR-384 was overexpressed, while the inhibition of AFAP1-AS1 decreased its ability to binding competitively to miR-384, resulting in the down-regulation of ACVR1 and enhancing miR-384 expression, ultimately inhibiting the progression of PC. The knockdown of AFAP1-AS1 or overexpression of miR-384 was confirmed to impair PC cell self-renewal ability, tumorigenicity, invasion, migration and stemness.ConclusionsTaken together, AFAP1-AS1 functions as an endogenous RNA by competitively binding to miR-384 to regulate ACVR1, thus conferring inhibitory effects on PC cell stemness and tumorigenicity.

Long non-coding RNA AFAP1-AS1 promoting epithelial-mesenchymal transition of endometriosis is correlated with transcription factor ZEB1.

The role of the long non-coding RNA (lncRNA) actin filament associated protein 1 antisense RNA1 (AFAP1-AS1) in the etiology of endometriosis is unknown. Expression of epithelial-mesenchymal transition (EMT) markers was quantified using qRT-PCR, immunohistochemistry, and Western blotting. The proliferation, migration, and invasion of ectopic endometrial epithelial cells and Ishikawa cells were evaluated by MTT, EdU, wound healing, and transwell assays. Inflammatory cytokine levels were detected by ELISA. Luciferase assays were used to measure activity of the ZEB1 promoter site pGL3-P886. AFAP1-AS1 levels were much higher in ectopic endometrial tissues than that in eutopic tissues. Expression of ZEB1, E-cadherin, and keratin was obviously higher in eutopic tissues than those in ectopic tissues. In contrast, expression of vimentin and N-cadherin was significantly lower in eutopic tissue than those in ectopic tissues. After knockdown of AFAP1-AS1, the morphology of endometrial epithelial cells varied from spindle fiber shaped to polygon epithelioid and proliferation, migration, and invasion were each inhibited. The knockdown of AFAP1-AS1 significantly inhibited expression from promoter site pGL3-P886 of the EMT-related transcription factor ZEB1. The size of subcutaneous tumours in nude mice was significantly reduced after down-regulation of AFAP1-AS1 expression. Higher expression of AFAP1-AS1 positively correlated with greater EMT in ectopic endometrium of patients with endometriosis. Knockdown of AFAP1-AS1 inhibited E2-induced activity of promoter site pGL3-P886 of transcription factor ZTB1, suggesting that AFAP1-AS1 knockdown inhibited growth of endometrial epithelial cells and that pathogenesis may be correlated with EMT.

RETRACTED ARTICLE: Upregulation of the long non-coding RNA AFAP1-AS1 affects the proliferation, invasion and survival of tongue squamous cell carcinoma via the Wnt/\u03b2-catenin signaling pathway

BackgroundLong 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.MethodsThe 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.ResultsIn 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.ConclusionsTaken 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.

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.

Overexpression of LncRNA AFAP1-AS1 predicts poor prognosis and promotes cells proliferation and invasion in gallbladder cancer.

Long non-coding RNA actin filament-associated protein 1 antisense RNA 1 (AFAP1-AS1) has been elucidated to be associated with some kinds of human cancers. However, whether lncRNA AFAP1-AS1 implicates in tumor development of gallbladder cancer (GBC) remains largely unknown. This study aims to elucidate the tumorigenic role and regulatory function of lncRNA AFAP1-AS1 in gallbladder cancer. We analyzed lncRNA AFAP1-AS1 expression by quantitative real time PCR (qRT-PCR) in 40 gallbladder cancer tissue and adjacent normal tissues, survival plots were generated by Kaplan-Meier analysis and the log-rank test. The expression levels of transcription factor Twist1 and epithelial-to mesenchymal transition (EMT) makers (E-cadherin and Vimentin) were detected by quantitative real time PCR and western blotting analysis after knockdown of lncRNA AFAP1-AS1. The expression levels of lncRNA AFAP1-AS1 were significantly elevated in GBC tissues and GBC cell lines. In addition, the expression level of lncRNA AFAP1-AS1 was significantly associated with tumor sizes and the higher expression of lncRNA AFAP1-AS1 was correlated with poor prognosis in GBC patients. Knockdown of LncRNA AFAP1-AS1 suppressed cell growth and invasion in NOZ and GBC-SD cells. Furthermore, we found that knockdown of LncRNA AFAP1-AS1 in GBC cells inhibited EMT by down-regulating the transcription factor Twist1 and Vimentin and up-regulated the E-cadherin. Our results suggested lncRNA AFAP1-AS1 was correlated with poor prognosis in GBC patients and lncRNA AFAP1-AS1 might be novel therapeutic target in gallbladder cancer.