Background: Gastric cancer (GC) is a deadly disease, and its incidence is especially high in East Asia including China. Recently, some long non-coding RNA (lncRNAs) have been identified as oncogenes or tumor suppressors. This study aimed to determine the function and mechanism of lncRNA LOXL1-AS1 on the progression of GC.
Methods: RT-PCR was done to measure the expression levels of LOXL1-AS1 and miR-142-5p in GC tissues. The association between pathological indexes and LOXL1-AS1 expression was also analyzed. Human GC cell lines AGS and BGC823 were used as cell models. CCK-8 and colony formation assays were conducted to assess the effect of LOXL1-AS1 on the proliferation of GC cell lines. Transwell assay was conducted to determine the influence of LOXL1-AS1 on cell migration and invasion. Furthermore, luciferase reporter assay was carried out to confirm the relationship of miR-142-5p with LOXL1-AS1. Additionally, Western blot was done to detect the regulatory function of LOXL1-AS1 on PIK3CA, a target of miR-142-5p. In vivo experiment was also performed to validate the roles and mechanism of LOXL1-AS1 on the growth and metastasis of GC cells.
Results: LOXL1-AS1 expression in GC samples was significantly increased, which was correlated with unfavorable pathological indexes. Highly expressed LOXL1-AS1 was closely linked to shorter overall survival time and post-progression survival time of the patients. LOXL1-AS1 markedly modulated the malignant phenotypes of GC cells. Additionally, overexpressed LOXL1-AS1 notably reduced the expression of miR-142-5p, but enhanced the expression level of PIK3CA. In vivo experiments further validated that knockdown of LOXL1-AS1 inhibited the growth and metastasis of GC cells via regulating miR-142-5p and PIK3CA.
Conclusion: LOXL1-AS1 was a sponge of tumor suppressor miR-142-5p in GC, enhanced the expression of PIK3CA indirectly and functioned as an oncogenic lncRNA.
Keywords: LOXL1-AS1, miR-142-5p, PIK3CA, gastric cancer