Low expression of lncRNA APTR promotes gastric cancer progression

LncRNA APTR amplification serves as a potential glioma biomarker and promotes glioma progression via miR-6734-5p/ TCF7/LEF1 axis

Background

Alu-mediated p21 transcriptional regulator (APTR) overexpression is detected in different human cancers; however, few reports have investigated APTR gene amplification conditions. Furthermore, whether APTR amplification is related to glioma malignancy and the underlying mechanism remain unknown.

Methods

APTR amplification and expression levels in 153 glioma samples were analyzed using qPCR. Correlations between APTR and patient prognosis were evaluated using Kaplan-Meier survival and COX regression analyses. Both in vitro and in vivo phenotypic assays were performed to confirm the carcinogenic effects of APTR in glioblastoma (GBM) cells. RNA-sequencing and RNA immunoprecipitation and luciferase reporter assays were performed to confirm APTR as a competing endogenous RNA (ceRNA) and to identify the downstream axis of APTR.

Results

Our results suggest that APTR amplification and overexpression are novel independent diagnostic biomarkers for predicting poor prognosis in patients with gliomas. APTR knockdown significantly repressed the proliferation and invasion of GBM cells, both in vitro and in vivo. APTR was demonstrated to absorb miR-6734-5p and upregulate TCF7 and LEF1 expression. Taken together, these results suggest that APTR promotes the malignant phenotypes of GBM by inducing TCF7 and LEF1 expression.

Conclusion

We identified APTR as a novel prognostic biomarker in patients with gliomas and confirmed that APTR is a ceRNA that promotes glioma progression via the APTR/miR-6734-5p/TCF7/LEF1 axis.

Expression and Significance of the Long Non-Coding RNA APTR in the Occurrence and Development of Lung Adenocarcinoma

As one of the three major malignant tumors, lung adenocarcinoma (LUAD), with its rapid progression and high mortality rate, has become the most dangerous factor endangering human health. This study aims to explore new potential molecular targets, explore the regulatory role of lncRNA APTR in LUAD, and provide a more theoretical basis for the selection of LUAD therapeutic targets. The expression of APTR in LUAD was detected by PCR experiments, and the relationship between APTR and patients' clinical conditions and prognosis was analyzed by chi-square test, multifactor Cox regression, and Kaplan-Meier. The interaction between APTR and miR-298 and the regulation of LUAD cellular activities by APTR/miR-298 were explored by the luciferase reporter gene system. APTR expression was found to be upregulated in LUAD tissues and cells, and the expression of APTR was revealed to be substantially linked with lymph node metastases and TNM stage. High expression of LUAD also predicted a poor prognosis for patients. Downregulation of APTR expression significantly inhibited the activities of LUAD cells. In addition, APTR targeted miR-298 and negatively regulated miR-298 expression. The inhibitory effect of APTR knockdown on LUAD cell activity was also reversed after transfection with miR-298 inhibitor. Increasing expression of APTR is associated with patients' poor prognosis, APTR targets miR-298 and promotes LUAD cellular activity through negative regulation of miR-298.

Downregulation of lncRNA EPB41L4A-AS1 promotes gastric cancer cell proliferation, migration and invasion

BACKGROUND

The incidence of gastric cancer ranks the first among digestive tract tumors in China. However, there are no specific symptoms in the early stage of the tumor and the diagnosis process is complex, so more effective detection methods are very needed. In this study, a novel long noncoding RNA (lncRNA) was introduced as a diagnostic biomarker for gastric cancer, which brought new thinking to the exploration of its pathological mechanism and clinical prediction.

METHODS

The level of lncRNA EPB41L4A-AS1 (EPB41L4A-AS1) in gastric cancer serum and cells was verified via real-time quantitative polymerase chain reaction (RT-qPCR). Receiver operating characteristic (ROC) curve was performed based on the EPB41L4A-AS1 level, and the diagnostic possibility of EPB41L4A-AS was analyzed. The chi-square test evaluated the correlation between EPB41L4A-AS expression and clinical information. The cells were cultured and transfected in vitro, and the mediations of abnormal EPB41L4A-AS level on the viability and motility of gastric cancer cells were verified through cell counting kit-8 (CCK-8) and Transwell assay. Furthermore, luciferase activity assay was performed to confirm the sponge molecule microRNA-17-5p (miR-17-5p) of EPB41L4A-AS1.

RESULTS

EPB41L4A-AS1 was decreased in gastric cancer, and low EPB41L4A-AS1 level indicated resultful diagnostic value. Overexpression of EPB41L4A-AS1 inhibited the activity of gastric cancer cells, while knockdown of EPB41L4A-AS1 promoted tumor deterioration. EPB41L4A-AS1 directly targeted and regulated the expression ofmiR-17-5p.

CONCLUSION

This study elaborated that EPB41L4A-AS1 is lowly expressed in gastric cancer. Silencing EPB41L4A-AS1 was beneficial to cell proliferation, migration, and invasion. EPB41L4A-AS1 provides a new possibility for the diagnosis of gastric cancer patients by targeting miR-17-5p.