The roles of imprinted SLC22A18 and SLC22A18AS gene overexpression caused by promoter CPG island hypomethylation as diagnostic and prognostic biomarkers for non-small cell lung cancer patients

Genomic imprinting is a process that involves one gene copy turned-off in a parent-of-origin-dependent manner. The regulation of imprinted genes is broadly dependent on promoter methylation marks, which are frequently associated with both oncogenes and tumor suppressors. The purpose of this study wa...

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Bibliographic Details
Authors: Noguera-Uclés, José Francisco, Boyero, Laura, Salinas, Ana, Varela, Juan Antonio Cordero, Benedetti, Johana Cristina, Bernabé-Caro, Reyes, Molina Pinelo, Sonia
Format: article
Status:Published version
Publication Date:2020
Country:España
Institution:Universidad de Sevilla (US)
Repository:idUS. Depósito de Investigación de la Universidad de Sevilla
OAI Identifier:oai:idus.us.es:11441/150340
Online Access:https://hdl.handle.net/11441/150340
https://doi.org/10.3390/cancers12082075
Access Level:Open access
Keyword:NSCLC
SLC22A18
IMPT1
TSSC5
SLC22A18AS
Genomic imprinting
Prognosis
Description
Summary:Genomic imprinting is a process that involves one gene copy turned-off in a parent-of-origin-dependent manner. The regulation of imprinted genes is broadly dependent on promoter methylation marks, which are frequently associated with both oncogenes and tumor suppressors. The purpose of this study was to assess the DNA methylation patterns of the imprinted solute-carrier family 22 member 18 (SLC22A18) and SLC22A18 antisense (SLC22A18AS) genes in non-small cell lung cancer (NSCLC) patients to study their relevance to the disease. We found that both genes were hypomethylated in adenocarcinoma and squamous cell carcinoma patients. Due to this imprinting loss, SLC22A18 and SLC22A18AS were found to be overexpressed in NSCLC tissues, which is significantly more evident in lung adenocarcinoma patients. These results were validated through analyses of public databases of NSCLC patients. The reversed gene profile of both genes was achieved in vitro by treatment with ademetionine. We then showed that high SLC22A18 and SLC22A18AS expression levels were significantly associated with worsening disease progression. In addition, low levels of SLC22A18AS were also correlated with better overall survival for lung adenocarcinoma patients. We found that SLC22A18 and SLC22A18AS knockdown inhibits cell proliferation in vitro. All these results suggest that both genes may be useful as diagnostic and prognostic biomarkers in NSCLC, revealing novel therapeutic opportunities.