GPC5, a novel epigenetically silenced tumor suppressor, inhibits tumor growth by suppressing Wnt/β-catenin signaling in lung adenocarcinoma

Abstract

Glypican-5 (GPC5) is a member of the heparin sulfate proteoglycans. Previous studies of GPC5 in lung tumorigenesis showed conflicting results. In this study, we confirmed that GPC5 was downregulated in lung adenocarcinoma tissues compared with adjacent normal lung tissues. The low expression of GPC5 was significantly associated with poor outcome in lung adenocarcinoma. To understand the biological mechanism of the downregulation, we examined the promoter methylation status of GPC5 gene. We found that GPC5 was significantly hypermethylated in lung cancer tissues and lung cancer cell lines compared with normal lung tissues. The methylation level of GPC5 was negatively correlated with its transcriptional expression. De-methylation experiments further confirmed that the loss of GPC5 expression was regulated by its hypermethylation. Overexpression of GPC5 inhibited proliferation, migration and invasion of lung cancer cells in vitro, and repressed tumor growth in vivo, whereas knockdown of GPC5 was able to reverse the effect. Furthermore, we demonstrated that GPC5 could suppress the Wnt/β-catenin signaling by binding to Wnt3a at the cell surface, which mediated its function as a tumor suppressor. Overall, these findings demonstrate that GPC5 is a novel epigenetically silenced tumor suppressor, which inhibits tumor growth by suppressing Wnt/β-catenin signaling in lung adenocarcinoma. Our findings substantially expand our understanding about the role and the molecular mechanism of GPC5 in tumorigenesis of lung cancer.

Subcellular localization of glypican-5 associates with dynamic cell motility and cell communication of the human mesenchymal stem cell line U3DT

“…Similar evidence has also been obtained in cerebellar granule cell precursors [6] and salivary adenoid carcinoma [7]. Conversely, overexpression of GPC5 inhibits prostate [8] and lung cancer cell proliferation [9]. In non-small cell lung cancer, some reports have suggested that GPC5 is a tumor promoter [10], whereas others insist that it is a tumor suppressor [11,12].…”

Hypoxia‐sensitive LINC01436 is regulated by E2F6 and acts as an oncogene by targeting miR‐30a‐3p in non‐small cell lung cancer

“…Cell counting kit-8 (CCK-8) assay, colony formation assay, cell migration and invasion assays were described previously (Yuan et al, 2016).…”

“…Western blot (WB) was performed as described previously (Yuan et al, 2016). The antibodies used in this study were rabbit monoclonal antibody to EPAS1 (HIF-2-alpha; 1 : 1000; Abcam Inc., Cambridge, MA, USA), rabbit monoclonal antibody to E2F6 (1 : 1000; Abcam) and rabbit polyclonal antibody to b-actin (1 : 5000; Abcam).…”

SNP rs4142441 and MYC co-modulated long non-coding RNA OSER1-AS1 suppresses non-small cell lung cancer by sequestering RNA-Binding Protein ELAVL1

“…Cell Counting Kit-8 (CCK-8) assay, colony formation assay, cell migration and invasion assays were performed as described in Yuan et al, 2016. [17] Animal experiments in vivo For in vivo tumorigenicity, ten male BALB/c-nude mice (4-week-old) were randomly divided into two groups, with ve mice in each group. Stable transfected A549 cells (5.0 × 10 6 ) were injected subcutaneously into the left anks of the nude mice (100 ul per mouse).…”

“…Western blot (WB) was performed as described previously (Yuan et al, 2016) [17]. The antibodies used in this study were rabbit monoclonal to MYC (Abcam Inc., Cambridge, MA) (1:2000; Abcam (ab32072)), rabbit monoclonal to ELAVL1 (1:5000; Abcam (ab200342)), rabbit monoclonal to AGO2 (1:2000; Abcam (ab186733)), rabbit monoclonal to BCL2L11 (1:2000; Abcam (ab32158)), rabbit monoclonal to Histone H3 (1:5000; Abcam (ab176842)), rabbit polyclonal to β-actin (1:5000; Abcam (ab8227)).…”