miR-26a-5p Suppresses Wnt/β-Catenin Signaling Pathway by Inhibiting DNMT3A-Mediated SFRP1 Methylation and Inhibits Cancer Stem Cell-Like Properties of NSCLC

Abstract

Background. Lung cancer is a malignant cancer which results in the most cancer incidence and mortality worldwide. There is increasing evidence that the pattern of DNA methylation affects tumorigenesis and progression. However, the molecules and mechanisms regulating DNA methylation remain unclear. Methods. The expression of miR-26a-5p in NSCLC cell lines was detected by qPCR and verified in NSCLC tissues from TCGA using Limma R package. CCK-8 assay, plate clone formation assay, flow cytometry, and sphere formation assay were used to detect the cell proliferation, colony formation, cell cycle, and cancer stem cell- (CSC-) like property in NSCLC cell lines. The immunoblotting was used to detect the protein levels of DNMT3A, SFRP1, and Ki67. Global DNA methylation levels and DNA methylation levels of SFRP1 promoter were examined using ELISA and MSP-PCR assay, respectively. The distribution of β-catenin was examined using immunofluorescence (IF). Besides, xenograft mouse model was used to investigate the antitumor effects of miR-26a-5p in vivo. The pathology and protein levels were, respectively, detected by hematoxylin and eosin (H&E) and immunocytochemistry (IHC). Results. The expression of miR-26a-5p was downregulated in the tumor tissues comparted to adjacent normal tissues as well as NSCLC cell lines compared to normal lung epithelial cell (BEAS2B). The overexpression of miR-26a-5p inhibited cell proliferation, colony formation, CSC-like property, and arrested cell cycle at G1 phase. DNMT3A was a target of miR-26a-5p and upregulated DNA methylation on SFRP1 promoter. Mechanistically, miR-26a-5p repressed cell proliferation, colony formation, CSC-like property, and arrested cell cycle at G1 phase by binding DNMT3A to reduce DNA methylation levels of SFRP1 then upregulated SFRP1 expression. Moreover, miR-26a-5p exerted antitumor effects in vivo. Conclusion. Our results revealed that miR-26a-5p acted as a tumor suppressor through targeting DNMT3A to upregulate SFRP1 via reducing DNMT3A-dependent DNA methylation.

Unraveling the Post-Translational Modifications and therapeutical approach in NSCLC pathogenesis

“…Thus, SAE1 knockdown reversed the effects of miR-382–3p inhibition, which increased proliferation and decreased apoptosis in lung adenocarcinoma cell line (A549 and H1299) [160] . Another miR-708–5p reduces the onset, growth, and stemness of NSCLC by directly targeting the enzyme of DNA methylation DNMT3A [161] , similarly recent study has mentioned miR-26a-5p also targets DNMT3A in NSCLC [162] . The histone deacetylase SIRT 7 is a direct target of miR-3666 which reduces NSCLC growth [163] .…”

Comprehensive analysis of the clinical and prognostic significance of SFRP1 and PRKCB expression in non-small cell lung cancer: a retrospective analysis

“…The tumor suppression function of SFRP1 has also been supported by the findings that gene silencing caused by methylation of the four members of this family weakens the inhibitory effect of SFRP on the Wnt pathway, leads to an abnormal activation of the pathway, and causes the occurrence and development of various tumors (Suzuki et al ., 2002; Chung et al ., 2009; Valencia et al ., 2009; Mo et al ., 2018; Baharudin et al ., 2020; Rueda-Carrasco et al ., 2021). In NSCLC, SFRP1 downregulation promotes cancer stem cell-like property and epithelial–mesenchymal transition, ultimately functions as a metastasis promoter (Ren et al ., 2013; Taguchi et al ., 2016; Yu et al ., 2022). However, the prognostic role of SFRP1 in NSCLC remains unknown.…”

Correlation of DNA methylation of DNMT3A and TET2 with oral squamous cell carcinoma

“…DNMT3A is involved in the oncogenic process of various tumors by regulating the level of promoter methylation. Yu et al revealed that miR-26a-5p targeted DNMT3A to reduce the degree of global methylation in non-small cell lung cancer and restore the SFRP1 expression, thereby regulating cell viability and the stem-like phenotype by regulating the Wnt/β-catenin pathway [ 33 ]. Lu et al found DNMT3A promoted the Warburg effect and tumor malignant biological behavior by inhibiting the miR-603 expression.…”