Dysregulation of FOXO transcription factors in Epstein-Barr virus-associated gastric carcinoma
VIRUS RESEARCH
Authors: Liu, Wen; Song, Ying-ying; Wang, Jia-yi; Xiao, Hua; Zhang, Yan; Luo, Bing
Abstract
Epstein-Barr virus (EBV) infection is associated with the development of gastric cancer (GC). Forkhead box class O (FOXO) transcription factors play important roles in tumor suppression. This study aims to investigate the interplay between EBV and FOXOs in EBV-associated GC (EBVaGC). The results showed that EBV infection of GC cells led to the downregulation of FOXO1 by the inhibition of its mRNA and protein expression. FOXO3 protein is repressed by EBV infection. FOXO4 mRNA is upregulated in EBV-positive cell lines, while its protein expression is downregulated. FOXO1, FOXO3 and FOXO4 proteins are upregulated following PI3K inhibition in GT39 cells, confirming that they are partially suppressed by the PI3K/AKT pathway. However, the upregulation of FOXO1 and FOXO3 by single transfection with LMP1 or LMP2A implies that the dysregulation of FOXOs in EBVaGC is affected by various EBV latent genes and that PI3K/AKT signaling is not the only mechanism of FOXO regulation.
The positive feedback loop FOXO3/CASC11/miR-498 promotes the tumorigenesis of non-small cell lung cancer
BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS
Authors: Yan, Ruicheng; Jiang, Ying; Lai, Bingyu; Lin, Yaqiong; Wen, Jingwei
Abstract
An increasing number of studies have indicated that long noncoding RNAs (IncRNAs) are involved in the regulation of non-small-cell lung cancer (NSCLC). Nevertheless, there are still numerous undiscovered mechanisms underlying this molecular regulation. Here, the results illustrated that CASC11 is overexpressed in NSCLC tumor tissues and cell lines, which is closely related to the clinical features of NSCLC and poor survival. In functional experiments, CASC11 was shown to promote proliferation and cycle progression and enhance NSCLC tumorigenesis. In mechanical investigations, CASC11 was shown to target the miR-498/FOX03 axis via a canonical competing endogenous RNA (ceRNA). In return, the transcription factor FOX03 targets the CASC11 promoter region, thereby accelerating its transcription. Our findings demonstrate a crucial role for CASC11 as an oncogene in promoting NSCLC. These results reveal that CASC11 might be a potential therapeutic target for NSCLC. (C) 2019 Published by Elsevier Inc.