DNA methylation plays a pivotal role in the development and progression of tumors. However, studies focused on the dynamic changes of DNA methylation in the development of hepatocellular carcinoma (HCC) are rare. To systematically illustrate the dynamic DNA methylation alternation from premalignant to early-stage liver cancer with the same genetic background, this study enrolled 5 HBV-related patients preceded with liver cirrhosis, pathologically identified as early-stage HCC with dysplastic nodules. Liver fibrosis tissues, dysplastic nodules and early HCC tissues from these patients were used to measure DNA methylation. Here, we report significant differences in the DNA methylation spectrum among the three types of tissues. In the early stage of HCC, DNA hypermethylation of tumor suppressor genes is predominant. Additionally, DNA hypermethylation in the early stage of HCC changes the binding ability of transcription factor TP53 to the promoter of tumor suppressor gene ZNF334, and inhibits the expression of ZNF334 at the transcription level. Furthermore, through a series of in vivo and in vitro experiments, we have clarified the exacerbation effect of tumor suppressor gene ZNF334 deletion in the occurrence of HCC. Combined with clinical data, we found that the overall survival and relapse-free survival of patients with high ZNF334 expression are significantly longer. Thus, we partly elucidated a sequential alternation of DNA methylation modification during the occurrence of HCC, and clarified the biological function and regulatory mechanism of the tumor suppressor gene ZNF334, which is regulated by related DNA methylation sites. Our study provides a new target and clinical evidence for the early diagnosis and sheds light on the precise treatment of liver cancer.

In vitro induced human regulatory T cells (iTregs) have in vivo therapeutic utility. MicroRNAs (miRNAs) are a family of approximately 22-nucleotide non-coding RNAs that are processed from longer precursors by the RNases Drosha and Dicer. miRNAs regulate post-transcriptional protein expression through messenger RNA destabilization or translational silencing; miR-142-3p regulates natural Treg function through autophagy. We hypothesized that this miRNA may also have an iTreg regulation function. Antagomir-mediated knockdown of miR-142-3p improved Foxp3 (forkhead box P3) expression, regulatory function, cytokine expression, and apoptosis of iTregs in vitro, with or without inflammatory cytokine stimulation. miR-142-3p knockdown increased autophagy-related protein 16-1-mediated autophagy. Target prediction and luciferase assay results indicated that miR-142-3p binds directly to lysine demethylase 6A (KDM6A), which resulted in demethylation of H3K27me3 and in turn upregulated expression of the anti-apoptotic protein Bcl-2. Based on these results, we propose a novel strategy that uses knockdown of miR-142-3p to enhance anti-apoptotic ability and function of iTregs by increasing KDM6A and Bcl-2 expression. This approach might be used as a treatment to control established chronic immune-mediated autoimmune and inflammatory diseases.

HCC is globally recognized as a major health threat. Despite significant progress in the development of treatment strategies for liver cancer, recurrence, metastasis, and drug resistance remain key factors leading to a poor prognosis for the majority of liver cancer patients. Thus, there is an urgent need to develop effective biomarkers and therapeutic targets for HCC. Collagen, the most abundant and diverse protein in the tumor microenvironment, is highly expressed in various solid tumors and plays a crucial role in the initiation and progression of tumors. Recent studies have shown that abnormal expression of collagen in the tumor microenvironment is closely related to the occurrence, development, invasion, metastasis, drug resistance, and treatment of liver cancer, making it a potential therapeutic target and a possible diagnostic and prognostic biomarker for HCC. This article provides a comprehensive review of the structure, classification, and origin of collagen, as well as its role in the progression and treatment of HCC and its potential clinical value, offering new insights into the diagnosis, treatment, and prognosis assessment of liver cancer.