Transcriptional Regulation between CCAT2 and AR in Prostate Cancer Cell Lines / 中国生物化学与分子生物学报

AR (androgen receptor) and CCAT2 are two prostate cancer (PCa)-related genes whereas their relationship is not yet reported. AR is the classical major functional gene in PCa progression. CCAT2, a non-coding gene, was identified based on big-data GWAS (Genome-Wide Association Studies) in the year of 2013. Androgen deprivation therapy (ADT) is usually used to treat PCa in the early stage. After persistent androgen deprivation, PCa would generally lead to castration resistant prostate cancer (CRPC), whereas the mechanism is yet unclear. Here we explore the function of AR and CCAT2 in PCa progression, especially their relation in androgen sensitive and insensitive cell model LNCap and DU145. We found a loop between AR and CCAT2 transcription by over-expression and knock-down strategies. In DU145 cells, G-CCAT2 activated AR mRNA level 2. 6 times, while T-CCAT2 inhibited it to 0. 2 times (P<0. 05). In LNCaP cells, G-CCAT2 could activate AR mRNA levels 1. 5 times, and TCCAT2 had no significant effect (P<0. 05). Under overexpression of AR in DU145 cells, the expression of CCAT2 increased 2. 9 times (P < 0. 05). The abundance of CCAT2 decreased to 0. 48 (P < 0. 05) in LNCaP cells by AR knock-down. Reporter gene analysis showed that CCAT2 could function on the AR promoter. We then performed CCK8 assays and AR protein level detection as supplement for the new gene CCAT2 studies. Finally we primarily studied some target genes that are related to AR and CCAT2 . The results showed that the G-CCAT2 transcript could activate AR expression in LNCap cells while UCCAT2 had no significant effect. In DU145 cells, G-CCAT2 exhibited a more relative stronger activation effect on AR, and U-CCAT2 could inhibit AR transcription. AR activates the transcriptional activity of CCAT2 in both cell lines, suggesting a feedback regulation between them. Our data showed that there would be a feedback loop between CCAT2 and AR, which may indicate a new method for PCa treatment.

Effect of lncRNA CCAT2 on proliferation and cell cycle of cervical cancer CaSki cells / 中国肿瘤生物治疗杂志

@#[Abstract] Objective: To investigate the effect of long non-coding RNA (lncRNA)-CCAT2 on the proliferation and cell cycle of cervical cancer cells. Methods: The expression of CCAT2 in 3 cervical cancer cell lines (HeLa, C-33A, and CaSki) was detected by qPCR and the cell line with the highest expression level was selected for subsequent experiments. CCAT2 overexpression and interference vectors were designed and synthesized. After transfection, qPCR was performed to detect the transfection efficiency. The cells were divided into 5 groups: control, sh-EV (empty vector), overExp-EV , sh-CCAT2, and overExp-CCAT2. MTT assay was performed to evaluate cell viability. Flow cytometry was performed to measure cell cycle. WB was performed to detect the expressions of Ki67, cyclin D1, and cyclin dependent kinase 4 (CDK4). Results: Among HeLa, C-33A, and CaSki cells, the highest expression of CCAT2 was found in CaSki cells. CCAT2 overexpression and interference vectors were successfully transfected into the CaSki cells. Compared with the control group, the cells viability and proliferation in the sh-CCAT2 group was significantly decreased (all P<0.01), the proportion of cells in the G1 phase was significantly increased (P<0.01), and the expression levels of Ki67, cyclin D1, and CDK4 were significantly decreased (all P<0.01). However, in the overExp-CCAT2 group, the cell proliferation was enhanced and the expression levels of Ki67, cyclin D1, and CDK4 were significantly increased (all P<0.01). Conclusion: CCAT2 affects proliferation and cell cycle of cervical cancer cells by regulating the expressions of their associated proteins.

CCAT2 is an oncogenic long non-coding RNA in pancreatic ductal adenocarcinoma

Abstract Background Pancreatic ductal adenocarcinoma (PDAC) is highly aggressive with poor prognosis. Long non-coding RNAs (lncRNAs), a group of non-coding RNAs, play important roles in the progression of PDAC. This study aimed to investigate the potential involvement of lncRNA CCAT2 in PDAC tumorigenesis. Methods Expression of CCAT2 was detected by quantitative real-time PCR (qRT-PCR) in 80 human PDAC tissues and three PDAC cell lines. The effects of CCAT2 silencing in PANC-1 cells on cell proliferation and invasion were studied using MTT assay and transwell assay, respectively. The effect of CCAT2 silencing on tumorigenesis was assessed by PANC-1 xenograft in vivo. Using si-KRAS, the role of KRAS to regulate CCAT2 was evaluated by qRT-PCR and luciferase reporter assay. The involvement of MEK/ERK and PI3K/AKT signaling in CCAT2 regulation was investigated by pathway inhibitors PD98059 and LY294002, respectively. Results CCAT2 was significantly elevated in high-grade PDAC tissues and higher CCAT2 expression was correlated with lower survival rate in PDAC patients. CCAT2 was up-regulated in PDAC cell lines, as compared with normal pancreatic cells. Silencing of CCAT2 inhibited cell proliferation and invasion in PANC-1 cells in vitro, and attenuated tumorigenesis of PANC-1 xenograft in vivo. Furthermore, CCAT2 was regulated by KRAS through MEK/ERK signaling pathway. Conclusions CCAT2 is an oncogenic lncRNA in PDAC likely regulated by the KRAS-MEK/ERK pathway. It could be a potential diagnostic biomarker and therapeutic target for PDAC.