RNF135 Promoter Methylation Is Associated With Immune Infiltration and Prognosis in Hepatocellular Carcinoma

Abstract

RING finger protein 135 has an important role in the occurrence of many cancers; however its regulation and function of RNF135 in hepatocellular carcinoma remains unknown. The promoter methylation status and mRNA expression of RNF135 was evaluated by methylation-specific PCR, semi-quantitative RT-PCR, and real-time quantitative PCR in HCC tissues and cell lines, and further analyzed from The Cancer Genome Atlas database. Wound healing assay, transwell migration, cell viability, and colony formation assay were performed to investigate the function of RNF135. GSEA analysis, TIMER database, and ESTIMATE algorithm were used to decipher the associated pathway and immune infiltration. The survival analysis was applied to assess the prognostic value of RNF135. RNF135 expression was downregulated in HCC tissues and 5 of 8 HCC cell lines, and was negatively correlated with its promoter hypermethylation. Demethylating regent decitabine restored RNF135 expression on the cellular level. Knockdown of RNF135 expression enhanced the migration of HCC cells, while RNF135 overexpression and decitabine treatment repressed cell migration. Bioinformatics analysis and immunohistochemistry revealed a positive relationship between RNF135 expression and six immune cell infiltrates (B cells, CD4+ T cells, CD8+ T cells, neutrophils, macrophages, and dendritic cells). Survival analysis disclosed that RNF135 hypermethylation is independently associated with poor clinical outcomes in HCC. Decreased RNF135 expression driven by promoter hypermethylation frequently occurred in HCC and associated with prognosis of HCC. RNF135 functions as a tumor suppressor and is involved in tumor immune microenvironment in HCC.

Discovery of novel DNA methylation biomarker panels for the diagnosis and differentiation between common adenocarcinomas and their liver metastases

“…Hypermethylation of these regions has been associated with epigenetic reprogramming, tumorigenesis, metastasis and poor prognosis 62 – 66 . In addition, promoter regions have been associated with downregulation of the corresponding genes 37 , 62 – 64 , 67 – 72 . Some of the selected regions have already been identified as potential diagnostic methylation biomarkers that differentiate between primary tumors, adjacent normal tissue samples and other tumor types 37 , 62 , 66 , 69 , 70 , 72 – 77 .…”

A pan-cancer analysis of ring finger protein 135 and its relationship to triple-negative breast cancer proliferation and metastasis

“…Targeting RNF135 and downregulating miR-485-3p enhanced glioblastoma cell proliferation and migration [ 13 ]. Earlier research established that RNF135 influences the growth of human glioblastoma through the ERK pathway [ 14 ]. Moreover, it was proven that ring finger proteins may have a key role in the development of cancer.…”

“…Several studies have investigated RNF135 in cancer, including tongue cancer [ 11 ], glioblastoma [ 12 , 13 ] and Hepatocellular Carcinoma [ 14 ]. However, the relationship between RNF135 and breast cancer has not been elucidated.…”

Epigenetic modification-related mechanisms of hepatocellular carcinoma resistance to immune checkpoint inhibition

“…High Dnmt3b expression in HCC is regulated by the IL-6/STAT3 signaling pathway, contributing to resistance to sorafenib and poor prognosis (85). DNA methylation in HCC may also alter genes involved in immune surveillance (86)(87)(88)(89). In sorafenib-resistant HCC cells, overexpression of DNIMT1 is accompanied by PD-L1 expression, causing poor prognosis (90).…”