Cancer-associated Transcript Research Articles

Long Non-Coding RNA BLACAT1 in Human Cancers.

Long non-coding RNAs (lncRNAs) are a cluster of RNAs with more than 200 nucleotides in length, which lack protein-coding capacity. They are important regulators of numerous cellular processes, including gene transcription, translation, and posttranslational modification, especially in tumor initiation and progression. Aberrant expression of lncRNA bladder cancer–associated transcript 1 (BLACAT1) has been reported in various human cancers and was usually associated with unfavorable prognosis. Previous studies have revealed that dysregulation of BLACAT1 could promote the proliferation and metastasis of cancer cells. In this review, we summarize the present understanding of the functions and underlying mechanisms of BLACAT1 in the occurrence and development of various human cancers and discuss the roles of this lncRNA in cancers, including its promising application as a prognostic biomarker or a novel therapeutic target for malignancies.

Long Noncoding RNA CCAT1 Functions as a Competing Endogenous RNA to Upregulate ITGA9 by Sponging MiR-296-3p in Melanoma.

BackgroundMelanoma is aggressive and lethal melanocytic neoplasm, and its incidence has increased worldwide in recent decades. Accumulating evidence has showed that various long noncoding RNAs (lncRNAs) participated in occurrence of malignant tumors, including melanoma. The present study was designed to investigate function of lncRNA colon cancer-associated transcript-1 (CCAT1) in melanoma.MethodsThe expression levels of CCAT1, miR-296-3p and Integrin alpha9 (ITGA9) in melanoma tissues or cells were measured using real-time quantitative polymerase chain reaction (RT-qPCR). The concentrations of glucose and lactate were measured for assessing glycolysis of melanoma cells. 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazol-3-ium bromide (MTT), flow cytometry, and transwell assays were conducted to assess proliferation, apoptosis, and migration of melanoma cells. Western blot assay was performed to measure the protein expression of ITGA9, hexokinase 2 (HK2), and epithelial–mesenchymal transition (EMT)-related proteins in melanoma tissues or cells. The relationship among CCAT1, miR-296-3p, and ITGA9 was predicted and confirmed by bioinformatics analysis, dual-luciferase reporter, and RNA immunoprecipitation (RIP) assay, respectively. A xenograft experiment was established to assess the effect of CCAT1 knockdown in vivo.ResultsCCAT1 was effectively increased in melanoma tissues and cells compared with matched controls, and deficiency of CCAT1 impeded cell glycolysis, proliferation, migration while induced apoptosis, which were abrogated by knockdown of miR-296-3p in melanoma cells. In addition, our findings revealed that ITGA9 overexpression abolished miR-296-3p overexpression-induced effects on melanoma cells. Importantly, CCAT1 regulated ITGA9 expression by sponging miR-296-3p. The results of xenograft experiment suggested that CCAT1 silencing inhibited melanoma cell growth in vivo.ConclusionLncRNA CCAT1 promoted ITGA9 expression by sponging miR-296-3p in melanoma.

Novel role of ASH1L histone methyltransferase in anaplastic thyroid carcinoma

Anaplastic thyroid cancer (ATC) is one of the most aggressive human malignancies, with an average life expectancy of ∼6 months from the time of diagnosis. The genetic and epigenetic changes that underlie this malignancy are incompletely understood. We found that ASH1-like histone lysine methyltransferase (ASH1L) is overexpressed in ATC relative to the much less aggressive and more common differentiated thyroid cancer. This increased expression was due at least in part to reduced levels of microRNA-200b-3p (miR-200b-3p), which represses ASH1L expression, in ATC. Genetic knockout of ASH1L protein expression in ATC cell lines decreased cell growth both in culture and in mouse xenografts. RNA-Seq analysis of ASH1L knockout versus WT ATC cell lines revealed that ASH1L is involved in the regulation of numerous cancer-related genes and gene sets. The pro-oncogenic long noncoding RNA colon cancer-associated transcript 1 (CCAT1) was one of the most highly (approximately 68-fold) down-regulated transcripts in ASH1L knockout cells. Therefore, we investigated CCAT1 as a potential mediator of the growth-inducing activity of ASH1L. Supporting this hypothesis, CCAT1 knockdown in ATC cells decreased their growth rate, and ChIP-Seq data indicated that CCAT1 is likely a direct target of ASH1L's histone methyltransferase activity. These results indicate that ASH1L contributes to the aggressiveness of ATC and suggest that ASH1L, along with its upstream regulator miR-200b-3p and its downstream mediator CCAT1, represents a potential therapeutic target in ATC.

Sevoflurane Inhibits Proliferation, Invasion, but Enhances Apoptosis of Lung Cancer Cells by Wnt/β-catenin Signaling via Regulating lncRNA PCAT6/miR-326 Axis.

Sevoflurane was frequently used as a volatile anesthetic in cancer surgery. However, the potential mechanism of sevoflurane on lung cancer remains largely unclear. In this study, lung cancer cell lines (H446 and H1975) were treated by various concentrations of sevoflurane. 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assessment and colony formation assay were performed to detect the cell viability and proliferation, separately. Also, transwell assay or flow cytometry assay was applied as well to evaluate the invasive ability or apoptosis in lung cancer cells, respectively. Western blot assay was employed to detect the protein levels of β-catenin and Wnt5a. Moreover, quantitative real-time polymerase chain reaction (qRT-PCR) was used to examine the expression level of prostate cancer-associated transcript 6 (PCAT6) and miR-326 in lung cancer tissues and cells. The target interaction between miR-326 and PCAT6 or Wnt5a was predicted by bioinformatics analysis and verified by the dual-luciferase reporter gene assay. Sevoflurane inhibited the abilities on viability, proliferation, invasion, and activation of Wnt/β-catenin signaling, but promoted apoptosis of H446 and H1975 cells in a dose-dependent manner. The expression of PCAT6 was increased in lung cancer tissues and cells, except for that of miR-326. Besides, sevoflurane could lead to expressed limitation of PCAT6 or improvement of miR-326. This process presented a stepwise manner. Up-regulation of PCAT6 restored the suppression of sevoflurane on abilities of proliferation, invasion, rather than apoptosis, and re-activated the Wnt5a/β-catenin signaling in cells. Moreover, the putative binding sites between miR-326 and PCTA6 or Wnt5a were predicted by starBase v2.0 software online. PCAT6 suppressing effects on cells could be reversed by pre-treatment with miR-326 vector. The promotion of Wnt5a inverted effects led from miR-326 or sevoflurane. Our study indicated that sevoflurane inhibited the proliferation, and invasion, but enhanced the apoptosis in lung cancer cells by regulating the lncRNA PCAT6/miR-326/Wnt5a/β-catenin axis.

Knockdown of lncRNA PCAT6 Enhances Radiosensitivity in Triple-Negative Breast Cancer Cells by Regulating miR-185-5p/TPD52 Axis.

BackgroundLong non-coding RNAs (lncRNAs) have been reported to play essential roles in regulating the radiosensitivity of cancers. Prostate cancer-associated transcript 6 (PCAT6) exerts oncogenic roles in several tumors. However, the roles of PCAT6 and its underlying mechanism in regulating the radiosensitivity of triple-negative breast cancer (TNBC) have not been investigated.MethodsThe expression levels of PCAT6, microRNA-185-5p (miR-185-5p) and tumor protein D52 (TPD52) were determined by quantitative real-time polymerase chain reaction (qRT-PCR). Cell viability, apoptosis and colony formation were assessed by Cell Counting Kit-8 (CCK-8) assay, flow cytometry and colony formation assay, respectively. The interaction between miR-185-5p and PCAT6 or TPD52 was predicted by bioinformatics analysis and verified by dual-luciferase reporter assay. Western blot was carried out to detect the protein level of TPD52.ResultsPCAT6 and TPD52 were highly expressed and miR-185-5p was lowly expressed in TNBC tissues and cells, which was associated with an aggressive tumor phenotype in patients, affecting lymph node metastasis and clinical stage. PCAT6 or TPD52 knockdown or miR-185-5p overexpression enhanced the radiosensitivity of TNBC cells via inhibiting proliferation and inducing apoptosis. PCAT6 directly interacted with miR-185-5p and negatively regulated miR-185-5p expression. Moreover, TPD52 was confirmed as a target of miR-185-5p. Besides, PCAT6 regulated the radiosensitivity of TNBC cells through acting as a molecular sponge of miR-185-5p to modulate TPD52 expression.ConclusionKnockdown of PCAT6 promoted the radiosensitivity of TNBC cells through regulating miR-185-5p/TPD52 axis, providing a vital theoretical basis to improve the radiotherapy efficiency of TNBC.

Abnormal lncRNA CCAT1/microRNA-155/SIRT1 axis promoted inflammatory response and apoptosis of tubular epithelial cells in LPS caused acute kidney injury

BackgroundsAcute kidney injury (AKI) is characterized by excessive inflammatory response and apoptosis in tubular epithelial cells. Recent studies suggested that long non-coding RNAs colon cancer-associated transcript-1 (CCAT-1) and microRNA-155 (miR-155) might regulate cell death and inflammation. We aimed to explore the role of CCAT-1/miRNA-155 axis in the AKI. MethodsLPS was applied to establish in vitro and in vivo models of AKI using HK2 cells and pcDNA-CCAT1 transgenic mice, respectively. Gene overexpression or knockdown were performed through plasmids transfection. Apoptosis were determined by qRT-PCR, western blotting (Fas, FasL, Caspase-3), AnnexinV/PI staining and TUNEL assay. Cytokines were assessed by ELISA. Interaction of CCAT1/miR-155 and miR-155/SIRT1 were detected by dual-luciferase reporter assay. RNA immunoprecipitation (RIP) was also performed to determine CCAT1/miR-155 interaction. Pathological changes of AKI were evaluated using H&E staining, blood urine nitrogen (BUN) and serum creatinine (Cr) detection kits. The degree of renal fibrosis was determined by Masson trichrome stain. ResultsLPS administration reduced CCAT1 and SIRT1 expression, but increased miR-155 levels in tubular epithelial cells in vitro. Luciferase assay demonstrated that miR-155 might bind to and regulate CCAT1 and SIRT1. RIP further confirmed the direct interaction of CCAT1 and miR-155. Restoration of CCAT1 attenuated LPS induced inflammation and apoptosis through sequestering miR-155. The anti-inflammation and pro-survival effects of CCAT1 overexpression and miR-155 inhibition were abolished by SIRT1 knockdown, as indicated by the expression of cytokine and apoptotic markers, as well as H&E, BUN and Cr detection. Dysregulated CCAT1/miR-155/SIRT1 pathway regulated disease progression in a murine model of LPS-induced AKI, and NF-κB pathway involved in. ConclusionCCAT1 restoration sequestered miR-155, leading to upregulation of SIRT1 and alleviated LPS induced renal tubular epithelial cell damage in vitro and in vivo.

Long non-coding RNA colon cancer-associated transcript-1 regulates tumor cell proliferation and invasion of non-small-cell lung cancer through suppressing miR-152.

Lung cancer serves as one of the most common cancers in the world, and approximately 50% of non-small-cell lung cancer (NSCLC) patients are found to be aged >70 when diagnosed. In this study, we aimed to explore the effect of long non-coding RNAs colon cancer-associated transcript-1 (CCAT1) in NSCLC. A total of 72 clinical samples from older NSCLC patients were collected for analysis. The relative mRNA level of CCAT1 was detected through real-time polymerase chain reaction. Overall survival of NSCLC patients was detected through Kaplan-Meier survival analysis. MTT assays were used to detect cell proliferation. Cell invasion was determined by transwell assay. Protein levels were detected through western blot. CCAT1 expression levels significantly increased in NSCLC tumor tissues and were associated with poor overall survival of NSCLC patients. CCAT1 promotes cell proliferation, cell invasion and epithelial-mesenchymal transition of NSCLC cell lines. CCAT1 binds with miR-152, and the effect of si-CCAT1 in NSCLC cell proliferation, cell invasion and epithelial-mesenchymal transition was partially reversed by anti-miR-152. Long non-coding RNA CCAT1 regulates tumor cell proliferation and invasion in NSCLC through suppressing miR-152. Geriatr Gerontol Int 2020; ••: ••-••.

Long Non-coding RNA CCAT1 Sponges miR-454 to Promote Chemoresistance of Ovarian Cancer Cells to Cisplatin by Regulation of Surviving.

PurposeColon cancer-associated transcript 1 (CCAT1) was identified as an oncogenic long non-coding RNA (lncRNA) in a variety of cancers. However, there was a lack of understanding of the mechanism by which CCAT1 conferred cisplatin (also known as DDP) resistance in ovarian cancer cells.Materials and MethodsCell viability of A2780, SKOV3, A2780/DDP, and SKOV3/DDP cells upon cisplatin treatment was monitored by MTT assay. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) detected the expression levels of CCAT1 and miR-454. The effect of sh-CCAT1 on cisplatin response was investigated in xenografts study. Bioinformatic analysis, luciferase reporter assay and qRT-PCR were conducted to validate the direct interaction among CCAT1, miR-454, and survivin. Apoptosis was determined by flow cytometry after dual staining of Annexin-V-FITC/propidium iodide, and the expression of apoptosis-related proteins Bcl-2, Bax and survivin were detected by qRT-PCR and Western blotting. Xenograft study was conducted to monitor in vivo tumor formation.ResultsCCAT1 was highly expressed in cisplatin-resistant ovarian cancer cell line A2780/DDP and SKOV3/DDP. Knockdown of CCAT1 restored sensitivity to cisplatin in vitro and in vivo. Our data revealed that silencing of CCAT1 promoted cisplatin-induced apoptosis via modulating the expression of pro- or anti-apoptotic proteins Bax, Bcl-2, and survivin. CCAT1 directly interacted with miR-454, and miR-454 overexpression potentiated cisplatin-induced apoptosis. Survivin was identified as a functional target of miR-454, restoration of survivin attenuated the effect of miR-454 on cisplatin response. In addition, miR-454 inhibitor or overexpression of survivin was found to abolish sh-CCAT1–induced apoptosis upon cisplatin treatment.ConclusionCCAT1/miR-454/survivin axis conferred cisplatin resistance in ovarian cancer cells.

Knockdown of lncRNA CCAT1 enhances sensitivity of paclitaxel in prostate cancer via regulating miR-24-3p and FSCN1

ABSTRACTDrug resistance limits the efficacy of chemotherapy in human cancers. Previous studies reported that long noncoding RNA colon cancer-associated transcript 1 (CCAT1) regulated progression of prostate cancer (PCa). However, the potential role of CCAT1 in the sensitivity of paclitaxel (PTX) in PCa and its mechanism remain largely unknown. The PTX-resistant PCa cells were established in PC3 and DU145 cells by increasing concentrations of PTX. The expressions of CCAT1, microRNA-24-3p (miR-24-3p) and fascin1 (FSCN1) were measured by quantitative real-time polymerase chain reaction. The viability and apoptosis were detected by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide assay, flow cytometry and western blot, respectively. The interaction among CCAT1, miR-24-3p and FSCN1 was explored by luciferase activity, RNA immunoprecipitation, RNA pull-down and western blot, respectively. Results showed that the expressions of CCAT1 were up-regulated and miR-24-3p was down-regulated in PCa and PTX-resistant PCa cells (PC3-TXR and DU145-TXR). Knockdown of CCAT1 or overexpression of miR-24-3p inhibited survival rate, half maximal inhibitory concentration (IC50) of PTX but increased apoptosis in PC3-TXR and DU145-TXR cells after treatment of PTX. miR-24-3p was bound to CCAT1 and its abrogation reversed knockdown of CCAT1-mediated increase of PTX sensitivity in PC3-TXR and DU145-TXR cells. Moreover, FSCN1 restoration attenuated miR-24-3p-mediated inhibition of PTX resistance. Besides, FSCN1 level was enhanced in PCa and PTX-resistant PCa cells and regulated by CCAT1 and miR-24-3p. Our data suggested interference of CCAT1 contributed to PTX sensitivity in PCa by regulating miR-24-3p and FSCN1, indicating a novel avenue for treatment of PCa through regulating chemoresistance.

Long non-coding RNA CCAT1 promotes colorectal cancer cell migration, invasiveness and viability by upregulating VEGF via negative modulation of microRNA-218.

Increasing evidence has demonstrated that long non-coding (lnc) RNA is aberrantly expressed in numerous types of cancer. Colorectal cancer is a common malignancy; however, the role and mechanism underlying the influence of lncRNA-colon cancer associated transcript 1 (CCAT1) in colorectal cancer is yet to be elucidated. The present study revealed that CCAT1 is highly expressed in colorectal cancer tissues. Bioinformatics analysis and a dual-luciferase reporter gene assay indicated that CCAT1 and microRNA (miR)-218 had complementary binding sites. Furthermore, reverse transcription-quantitative PCR revealed that miR-218 was downregulated in colorectal cancer tissues compared with paired adjacent healthy tissues. To investigate the biological effects of CCAT1 on colorectal cancer cells, MTT and Transwell assays were performed. The results revealed that when compared with the control group, CCAT1-short hairpin (sh)RNA significantly inhibited colorectal cancer cell (SW480) viability and decreased migration and invasiveness. In addition, CCAT1-shRNA significantly reduced vascular endothelial growth factor (VEGF) expression in SW480 cells; however, these effects were partially rescued by an miR-218 inhibitor. Furthermore, it was revealed that the CCAT1-plasmid significantly promoted the viability of SW480 cells, increased cell migration and invasiveness, and significantly increased VEGF expression. However, these effects were also partially rescued by with a miR-218 mimic. Taken together, the present results identified that the CCAT1/miR-218 axis serves a key role in the regulation of colorectal cancer progression, which may be used as potential therapeutic target for the treatment of colorectal cancer.

CCAT2 contributes to hepatocellular carcinoma progression via inhibiting miR-145 maturation to induce MDM2 expression.

Long noncoding RNA colon cancer-associated transcript 2 (CCAT2) has been recently found to function as an oncogene in hepatocellular carcinoma (HCC). However, the mechanisms of CCAT2 in HCC development remain to be further explored. In the present study, we found that CCAT2 was abnormally upregulated in HCC cells and tissue specimens, exhibiting an inverse correlation with microRNA (miR)-145 expression. Mechanistic investigation showed that CCAT2 selectively blocked miR-145 processing, leading to decreased mature miR-145 presence. Both the in vitro and in vivo effects of CCAT2 knockdown on the proliferation and metastasis of HCC cells were reversed by miR-145 inhibitor, indicating that miR-145 modulation accounts for CCAT2-meditated HCC progression. Furthermore, miR-145 mimic dramatically suppressed HCC cells' proliferation and metastasis, revealing a tumor suppressor role of miR-145 in HCC. Mechanistically, MDM2 was predicted to be a potential target of miR-145. The luciferase and western blot assay demonstrated that miR-145 mimic largely inhibited MDM2 3'-untranslated region luciferase activity and MDM2 expression, followed by the upregulation of p53/p21 expression. Finally, the coexpression of MDM2 in miR-145 mimic-transfected HCC cells was able to largely compromise the inhibitory effects of miR-145 mimic on HCC cells' proliferation and metastasis in vitro and tumor formation in a xenograft model, confirming MDM2 is the critical mediator of miR-145 in HCC. In summary, our findings indicated that CCAT2 selectively blocks the miR-145 maturation process and plays an oncogene in HCC. Furthermore, a novel CCAT2/miR-145/MDM2 axis was revealed in HCC development and might provide a new target in the molecular treatment of HCC.

Knockdown of long non-coding RNA prostate cancer-associated transcript 1 inhibits the proliferation and metastasis of tongue squamous cell carcinoma cells by upregulating p21.

Long non-coding RNA (lncRNA) prostate cancer-associated transcript 1 (PCAT-1) is a long non-coding RNA involved in the development of various cancer types. Tongue squamous cell carcinoma (TSCC) is the most frequently diagnosed type of oral cancer worldwide. The present study aimed to explore the role of lncRNA PCAT-1 in TSCC, and to provide a preliminary assessment of the downstream pathways involved. The expression levels of lncRNA PCAT-1 in TSCC specimens were first assessed. Subsequently, lncRNA PCAT-1 was knocked down in TSCC cell lines and the resulting effect on the proliferation and apoptosis, as well as the metastatic and invasive potential of TSCC cells was investigated. To assess the downstream signaling resulting from lncRNA PCAT-1 inhibition, the expression of p21 was also detected. The results indicated that lncRNA PCAT-1 was upregulated in clinical TSCC compared with peri-tumor tissues. Inhibition of lncRNA PCAT-1 resulted in reduced proliferation and apoptosis of TSCC cells, in addition to the suppression of migration and invasion. Furthermore, the expression of p21 was induced following lncRNA PCAT-1 inhibition. Collectively, the present study demonstrated an oncogenic role for lncRNA PCAT-1 in TSCC; inhibition of lncRNA PCAT-1 reduced the growth, metastasis and invasion of TSCC, at least in part via the induction of p21 signaling.

LncRNA PCAT6 Accelerates the Progression and Chemoresistance of Cervical Cancer Through Up-Regulating ZEB1 by Sponging miR-543.

BackgroundCervical cancer (CC) is a common cancer with a poor prognosis due to the chemoresistance of CC cells to cisplatin. This study aimed to investigate the biological significance of lncRNA prostate cancer-associated transcript 6 (PCAT6) in the carcinogenesis of CC.Materials and MethodsQuantitative real-time polymerase chain reaction (qRT-PCR) was carried out to measure the abundance of PCAT6, miR-543 and zinc finger E-box binding protein 1 (ZEB1) in CC tissues and cells. The combination between miR-543 and lncRNA PCAT6 or ZEB1 was predicted by Starbase and was verified by dual-luciferase reporter assay, RNA-pull down assay and RNA immunoprecipitation (RIP) assay. Cell proliferation and chemoresistance to cisplatin were detected by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Cell apoptosis and metastasis were determined by flow cytometry, Western blot and transwell migration and invasion assays.ResultsThe abundance of ZEB1 protein was measured by Western blot assay. Murine xenograft model was established to confirm the function of lncRNA PCAT6 in vivo. The abundance of lncRNA PCAT6 was enhanced in CC tissues and cells compared with that in corresponding normal tissues and normal cervical epithelial cells Ect1/E6E7. MiR-543 was a target of PCAT6 and was negatively regulated by PCAT6. PCAT6 accelerated the proliferation, metastasis and the chemoresistance of CC cells to cisplatin while suppressed the apoptosis of CC cells. The overexpression of PCAT6 reversed the inhibitory effects of miR-543 accumulation on the proliferation, metastasis and chemoresistance of CC cells to cisplatin and the promoting impact on the apoptosis of CC cells. ZEB1 was a direct target of miR-543, and it functioned as the downstream gene of PCAT6/miR-543 to exert its oncogenic role in CC. PCAT6 promoted the growth of murine xenograft tumor through miR-543/ZEB1 axis in vivo.ConclusionLncRNA PCAT6 facilitated the proliferation, metastasis and chemoresistance of CC cells to cisplatin while impeded the apoptosis of CC cells via PCAT6/miR-543/ZEB1 axis. PCAT6/miR-543/ZEB1 axis might be a promising target for CC therapy.

LncRNA LUCAT1 promotes proliferation of ovarian cancer cells by regulating miR-199a-5p expression.

To investigate the biological effect of long non-coding ribonucleic acid (lncRNA) lung cancer-associated transcript 1 (LUCAT1) in the development of ovarian cancer. Real-time quantitative polymerase chain reaction (RT-qPCR) was utilized to detect the expression levels of lncRNA LUCAT1 in three human ovarian cancer cell lines (CaoV-3, SK-OV-3 and HO-8910) and the normal human ovarian surface epithelial cell line (IOSE80). Small interfering RNAs against lncRNA LUCAT1 (si-LUCAT1) were transfected into SK-OV-3 cells. Transfection efficiency of si-LUCAT1 was verified via RT-qPCR. Cell Counting Kit-8 (CCK-8) and colony formation assays were performed to test the effect of silencing lncRNA LUCAT1 on SK-OV-3 cell proliferation. The apoptosis was measured by flow cytometry. The miRcode database was searched to predict potential microRNAs (miRNAs) binding lncRNA LUCAT1. It was found that lncRNA LUCAT1 contained a highly conserved binding site of miR-199a-5p in the 3'-untranslated region (3'-UTR). Subsequently, the targeting relationship between them was determined through Dual-Luciferase reporter gene assay and RT-qPCR analysis. LncRNA LUCAT1 was highly expressed in three human ovarian cancer cell lines compared to that in normal ovarian surface epithelial cell line (p<0.05). The cell proliferation rate in SK-OV-3 cells with lncRNA LUCAT1 knockdown was remarkably lower in comparison to that in control group. Moreover, colony formation assay also revealed that the number of cell clones decreased significantly after knockdown of lncRNA LUCAT1 compared to that in control group (p<0.05). In addition, the apoptosis rate was distinctly elevated in the lncRNA LUCAT1 silencing group (p<0.05). Furthermore, a highly conserved binding site of miR-199a-5p was found in the 3'-UTR of lncRNA LUCAT1. Dual-Luciferase reporter gene assay exhibited that the Luciferase activity of LUCAT1-wt was significantly reduced after overexpression of miR-199a-5p (p<0.05), while that of LUCAT1-mut was unchangeable. Further analysis via RT-qPCR suggested that miR-199a-5p overexpression significantly decreased the expression level of lncRNA LUCAT1 (p<0.05). LncRNA LUCAT1 is overexpressed in ovarian cancer cells, which may target miR-199a-5p to exert its effects on driving the malignant development of ovarian cancer.

LncRNA CCAT1 Acts as a MicroRNA-218 Sponge to Increase Gefitinib Resistance in NSCLC by Targeting HOXA1

Long non-coding RNA (lncRNA) colon cancer-associated transcript-1 (CCAT1) has been reported to play important roles in the development and progression of multiple human malignancies. However, the functional role and molecular mechanism of CCAT1 on gefitinib resistance in non-small cell lung cancer (NSCLC) are largely unclear. The aim of this study is to explore the roles of CCAT1 on gefitinib resistance in NSCLC and to explore the underlying mechanisms. The quantitative real-time PCR (qRT-PCR) analysis was to investigate the expression pattern of CCAT1 in gefitinib-resistant NSCLC patient tissues and cell lines, and then the effects of CCAT1 on gefitinib resistance of NSCLC in vitro and in vivo. Furthermore, bioinformatics online program predictions and luciferase reporter assay were used to validate the association of CCAT1 and miR-218 in NSCLC cells. In this study, CCAT1 was observed to be upregulated in gefitinib-resistant patient tissues and cell lines. In vitro and in vivo experiments demonstrated that CCAT1 knockdown impaired cell proliferation and promoted the gefitinib-induced cell apoptosis. Furthermore, we demonstrated that CCAT1 acts as a sponge for miR-218, and verified that HOXA1 is a novel target of miR-218. These results suggest that CCAT1 may serve as a promising therapeutic target for the treatment of epidermal growth factor receptor (EGFR) plus NSCLC patients.

Expression levels and associations of five long non-coding RNAs in gastric cancer and their clinical significance.

Gastric cancer (GC) is a type of cancer that is commonly diagnosed worldwide due to a lack of early diagnostic, prognostic and therapeutic targets for this disease. The aim of the present study was to examine the expression levels of five long non-coding RNAs, namely PTPRG antisense RNA 1 (PTPRG-AS1), forkhead box P4 antisense RNA 1 (FOXP4-AS1), bladder cancer-associated transcript 2 (BLACAT2), ZXF2 and upregulated in colorectal cancer (UCC), to study their associations with patient characteristics and assess their prognostic efficacy, in order to determine the possibility of their application as GC biomarkers. The expression levels of long non-coding RNAs (lncRNAs) were determined by reverse transcription-quantitative PCR analysis of 61 pairs of GC tissues and adjacent healthy gastric mucosa tissues and GC cell lines. The Chi-square test was conducted to assess the associations of lncRNA expression levels with clinical characteristics of patients. The effect of UCC on GC cell proliferation was determined using in vitro functional experiments. The prognostic efficacy of FOXP4-AS1, BLACAT2 and UCC were examined in the Gene Expression Profiling Interactive Analysis database and those of PTPRG-AS1 were examined in the Kaplan Meier Plot database. Gene alteration frequencies of PTPRG-AS1 and BLACAT2 in GC were identified using the cBioPortal for Cancer Genomics. PTPRG-AS1, FOXP4-AS1, BLACAT2, ZXF2 and UCC were found to be upregulated in GC cell lines and GC tissues compared with adjacent normal tissues. PTPRG-AS1 and ZXF2 expression levels were associated with the expression status of the cell proliferation marker Ki67. UCC promoted the proliferation of GC cells in vitro and was associated with lymph node metastasis. Increased expression of FOXP4-AS1 indicated a favorable outcome in terms of disease-free survival, whereas high expression of PTPRG-AS1 was associated with poor survival rates for patients in different GC risk groups. BLACAT2 gene mutation was associated with poor disease-free survival outcome for patients with GC. The results suggest that PTPRG-AS1, FOXP4-AS1, BLACAT2, ZXF2 and UCC are potential biomarkers for the detection of GC at the molecular level and may be used as potential targets for GC therapy. The individual roles of these lncRNAs may be utilized for prognostic predictions.

Expression of prostate cancer-associated transcript 6 in serum of patients with liver cancer and the effect of its interference on biological function of liver cancer cells

Objective To investigate the expression of prostate cancer-associated transcript 6 (PCAT6) in the serum of hepatocarcinoma patients and its effect on the proliferation, migration, invasion and apoptosis of Hep3B cells. Methods The qPCR method was used to detect the level of long non-coding RNA (lncRNA) PCAT6 in serum and THLE-3, Hep3B and HepG2 cells. The Hep3B cells were randomly divided into blank control group (NC group), negative empty vector transfection group (si-con group) and lncRNA PCAT6 silencing group (si-PCAT6 group). Western blotting was used to detect the expression of matrix metalloproteinase (MMP)-2, MMP-9, cleaved cysteinyl aspartate-specific protease (Caspase)-3, cleaved Caspase-9, phosphatidylinositol 3 kinase (PI3K), phosphorylated-PI3K (p-PI3K), protein kinase B (Akt), and phosphorylated Akt (p-Akt) proteins. The cell proliferation was measured by methyl thiazol tetrazolium (MTT) assay. The apoptosis was examined by flow cytometry, and the migration and invasion was tested detected by Transwell chamber method. The SPSS 21.0 software was used for statistical analysis, and the measurement data were expressed as mean±standard deviation (SD). Results The expression level of lncRNA PCAT6 in patients with moderate or high differentiation (60.94%) was significantly higher than that in patients with low differentiation (6.25%) (χ2=22.968, P<0.01). The percentage of patients with high expression of lncRNA PCAT6 in T-stage Ⅱ-Ⅳ (57.81%) was significantly higher than that in stage Ⅰ (9.38%) (χ2=8.529, P<0.01). The expression of lncRNA PCAT6 in Hep3B cells (3.72±0.67) and HepG2 cells (3.38±0.53) was significantly higher than that in THLE-3 cells (1.03±0.14) (t=9.322 and 8.144, P<0.05). The expression of lncRNA PCAT6 (0.21±0.11) in si-PCAT6 group was significantly lower than that in si-CON group (0.96±0.15) (t=9.915, P<0.05), and the cell viability was significantly reduced at 24 h, 48 h and 72 h (t=3.280, 6.144 and 6.373, P<0.05). Western blotting showed that the expression of cleaved Caspase-3, cleaved Caspase-9, p-pi3k and p-Akt increased significantly (t=11.408, 14.628, 8.683 and 9.585, P<0.01), and the expression of MMP-2 and MMP-9 decreased significantly in si-PCAT6 group (t=10.568 and 10.814, P<0.01). The apoptosis rate of Hep3B cells increased significantly (t=21.075, P<0.01), and the migration and invasion of Transwell cells decreased significantly (t=12.816 and 12.707, P<0.01). Conclusion The serum lncRNA PCAT6 is highly expressed in HCC patients, which is related to the degree of HCC differentiation and T stage. Silencing lncRNA PCAT6 can inhibit the biological behaviors of HCC probably by inhibiting the Akt signaling pathway activation. Key words: Long non-coding RNA; Prostate cancer-associated transcript 6; Liver cancer; Biological function

Long Noncoding RNA LUCAT1 Promotes Multiple Myeloma Cell Growth by Regulating the TGF-β Signaling Pathway.

Objective:Long noncoding RNAs (lncRNAs) are potential biomarkers for cancers. Nevertheless, the ability of long noncoding RNA lung cancer-associated transcript 1 in patients with multiple myeloma remains unknown. The purpose of this current study was to figure out its function in multiple myeloma.Methods:Firstly, the expression of long noncoding RNA lung cancer-associated transcript 1 in cancer or normal tissues and serum from patients with multiple myeloma and normal donors was detected. Secondly, the expression of long noncoding RNA lung cancer-associated transcript 1 was overexpressed or silenced in U266 and H929 cells, respectively to detect changes of proliferation and apoptosis in multiple myeloma in vitro. Subsequently, the expression of transforming growth factor-β signaling pathway-related proteins was detected by western blot analysis. Finally, the effect of long noncoding RNA lung cancer-associated transcript 1 on the growth of multiple myeloma cells in vivo was evaluated by tumor xenograft in nude mice.Results:Long noncoding RNA lung cancer-associated transcript 1 was increased in cancer tissues and serum of patients with multiple myeloma as well as multiple myeloma cells, which was correlated with dismal prognosis of patients with multiple myeloma. Overexpression of long noncoding RNA lung cancer-associated transcript 1 promoted the activity of U266 and H929 cells, while inhibition of long noncoding RNA lung cancer-associated transcript 1 suppressed the activity of U266 and H929 cells. In addition, long noncoding RNA lung cancer-associated transcript 1 was found to promote activation of the transforming growth factor-β signaling pathway. Furthermore, long noncoding RNA lung cancer-associated transcript 1 knockdown restricted the growth of multiple myeloma cells in vivo.Conclusion:This study suggests that suppression of long noncoding RNA lung cancer-associated transcript 1 inhibits the activation of transforming growth factor-β signaling pathway, thereby inhibiting the growth of multiple myeloma cells.

Silencing of long non-coding RNA PCAT6 restrains gastric cancer cell proliferation and epithelial-mesenchymal transition by targeting microRNA-15a.

Gastric cancer (GC) is a high mortality disease. We studied the function and mechanism of long non-coding RNA prostate cancer-associated transcript 6 (lncRNA PCAT6) on cell proliferation and epithelial-mesenchymal transition (EMT) in GC cells. CCK-8, flow cytometry and colony formation assay were respectively used to detect the cell viability, apoptosis and colony formation. PCAT6 and miR-15a expression were changed by cell transfection. Moreover, the level of Cyclin D1, p53, Bax, Cleaved caspase-3 and relate-proteins of EMT and cell pathways were investigated by Western blot. Besides, the level of miR-15a and PCAT6 was tested by RT-qPCR. Besides, the target relation between miR-15a and PCAT6 were tested by luciferase assay. PCAT6 was highly expressed in GC cells and tissues. Silencing of PCAT6 restrained the relate-proteins of cell proliferation and EMT. Furthermore, PCAT6 reversely regulated miR-15a and miR-15a inhibitor reversed the efficacy of sh-PCAT6 in cell proliferation and EMT. PCAT6 restrained the relate-proteins of RB/E2F and Wnt/β-catenin pathways and miR-15a reverse this progress. Finally, PCAT6 was a target of miR-15a. Silencing of lncRNA PCAT6 restrained proliferation and EMT of GC cells by targeting miR-15a via RB/E2F and Wnt/β-catenin pathways.

Silencing of Long Non-Coding RNA Colon Cancer-Associated Transcript 2 Inhibits the Growth and Metastasis of Gastric Cancer Through Blocking mTOR Signaling.

PurposeThis study aimed to evaluate the specific role of colon cancer-associated transcript 2 (CCAT2) on gastric cancer (GC), and reveal the potential regulatory mechanism relating to mammalian target of rapamycin (mTOR) signaling.MethodsThe expression of CCAT2 was detected in GC tissues and cells by quantitative real-time PCR (qRT-PCR), and its relation with the pathologic characteristics of GC patients was analyzed. HGC-27 and SGC-7901 cells were transfected with siRNA-CCAT2 to silence CCAT2, and HGC-27 cells were then treated with an mTOR agonist Leucine (Leu) to activate mTOR signaling. The cell proliferation was evaluated by cell viability and colony formation. The cell cycle and apoptosis, and the migration and invasion abilities were detected by Flow cytometry, and Transwell assay, respectively. The expression of PCNA (proliferation marker), Snail, N-cadherin, E-cadherin (invasion markers), P53, Caspase-8, Bcl-2 (apoptosis markers), LC3-II/LC3-I, ATG3, p62 (autophagy makers), phosphorylated mTOR (p-mTOR), p-AKT, and p-p70S6K (mTOR signaling markers) were detected by Western blot.ResultsCCAT2 was upregulated in GC tissues and cells, and positively associated with the maximum tumor diameter, lymphatic metastasis, TNM staging, and low overall survival rate (P < 0.05). siRNA-CCAT2 transfection significantly inhibited the viability, colony formation, and migration and invasion abilities, blocked the cell cycle in G0/G1 phase, and promoted the apoptosis and autophagy of SGC-7901 and HGC-27 cells (P < 0.05). In addition, siRNA-CCAT2 transfection significantly upregulated P53, Caspase-8, LC3-II/LC3-I and ATG3, and downregulated PCNA, Bcl-2, p62, p-mTOR, p-AKT and p-p70S6K in SGC-7901 and HGC-27 cells (P < 0.05). siRNA-CCAT2 reversed the tumor-promoting effect of mTOR signaling activation on HGC-27 cells (P < 0.05).ConclusionSilencing of CCAT2 inhibited the proliferation, migration and invasion, and promoted the apoptosis and autophagy of GC cells through blocking mTOR signaling.