NDRG4 promoter hypermethylation is a mechanistic biomarker associated with metastatic progression in breast cancer patients

Abstract

The risk of developing metastatic disease in breast cancer patients is traditionally predictable based on the number of positive axillary lymph nodes, complemented with additional clinicopathological factors. However, since lymph node-negative patients have a 20–30% probability of developing metastatic disease, lymph node information alone is insufficient to accurately assess individual risk. Molecular approaches, such as multigene expression panels, analyze a set of cancer-related genes that more accurately predict the early risk of metastasis and the treatment response. Here, we present N-Myc downstream-regulated gene 4 (NDRG4) epigenetic silencing as a mechanistic biomarker of metastasis in ductal invasive breast tumors. While aberrant NDRG4 DNA hypermethylation is significantly associated with the development of metastatic disease, downregulation of NDRG4 transcription and protein expression is functionally associated with enhanced lymph node adhesion and cell mobility. Here, we show that epigenetic silencing of NDRG4 modulates integrin signaling by assembling β1-integrins into large punctate clusters at the leading edge of tumor cells to promote an “adhesive switch,” decreasing cell adhesion to fibronectin and increasing cell adhesion and migration towards vitronectin, an important component of human lymph nodes. Taken together, our functional and clinical observations suggest that NDRG4 is a potential mechanistic biomarker in breast cancer that is functionally associated with metastatic disease.

Hypermethylation-mediated silencing of NDRG4 promotes pancreatic ductal adenocarcinoma by regulating mitochondrial function

“…Bisulfite sequencing also confirmed hypermethylation in the promoter region of NDRG4. More importantly, we firstly reported that NDRG4 was epigenetic silenced by hypermethylation of its promoter in PDAC, consistent with previous reports about its role in other pathological processes (15,17,18). Therefore, reactivating NDRG4 expression with a demethylation agent might have potential value for PDAC therapy.…”

“…Results showed that abnormal NDRG4 expression was associated with patients' outcome. Meanwhile, low expression of NDRG4 was found in GEO datasets and PDAC cells, consistent with its expression pattern in breast cancer (15), colon cancer (18), and gastric cancer. (14) These data suggest that NDRG4 also works as a suppressor in PDAC.…”

“…In colon and breast cancers, NDRG4 expression is decreased during the carcinogenesis process. Favorable outcome has been found in patients with higher NDRG4 expression (15,16). These results indicate that NDRG4 might be a tumor suppressor in carcinogenesis.…”

“…Hyper-methylation of CpG islands in the promoter region of suppressor is considered to be an important inducer of cancer progression, including colorectal cancer (19), gastric cancer (20), esophageal cancer (21), and PDAC (22). Recent reports have revealed that epigenetic mechanisms are particularly important in controlling NDRG4 expression in cancer, including colorectal cancer (18), gastric cancer (17), and breast cancer (15). The genomic structure of NDRG4 by online analysis showed a dense CpG island near the transcription initiation site.…”

The Role of Noncoding RNAs in the Regulation of Anoikis and Anchorage-Independent Growth in Cancer

“…Evidence provided indicated that miR-139-5p and miR-483-5p target N-Myc downstream-regulated gene 4 (NDRG4) and NDRG2, respectively, and that overexpression of either NDRG4 or NDRG2 inhibits the invasive capacity of cancer cells [ 33 ] ( Figure 1 and Table 1 ). NDRG4 and NDRG2 have also been regarded to exhibit the tumor suppressive function by inhibiting cell proliferation, migration, invasion, and metastasis in different types of cancer, such as glioblastoma and breast cancer [ 113 , 114 , 115 ]. However, it was validated that NDRG2 can support liver metastasis of cancer by switching macrophage phenotype from M1-like tumor-associated macrophages (TAMs) to M2-like TAMs [ 116 ], suggesting that further investigations are necessary to unveil the precise function of NDRG2.…”