N6-methyladenosine-modified oncofetal lncRNA MIR4435-2HG contributed to stemness features of hepatocellular carcinoma cells by regulating rRNA 2'-O methylation

Exploring non-coding RNA mechanisms in hepatocellular carcinoma: implications for therapy and prognosis

Hepatocellular carcinoma (HCC) is a significant contributor to cancer-related deaths in the world. The development and progression of HCC are closely correlated with the abnormal regulation of non-coding RNAs (ncRNAs), such as microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs). Important biological pathways in cancer biology, such as cell proliferation, death, and metastasis, are impacted by these ncRNAs, which modulate gene expression. The abnormal expression of non-coding RNAs in HCC raises the possibility that they could be applied as new biomarkers for diagnosis, prognosis, and treatment targets. Furthermore, by controlling the expression of cancer-related genes, miRNAs can function as either tumor suppressors or oncogenes. On the other hand, lncRNAs play a role in the advancement of cancer by interacting with other molecules within the cell, which, in turn, affects processes such as chromatin remodeling, transcription, and post-transcriptional processes. The importance of ncRNA-driven regulatory systems in HCC is being highlighted by current research, which sheds light on tumor behavior and therapy response. This research highlights the great potential of ncRNAs to improve patient outcomes in this difficult disease landscape by augmenting the present methods of HCC care through the use of precision medicine approaches.

Crosstalk between m6A modification and non-coding RNAs in HCC

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related deaths worldwide, with high morbidity and occurrence. Although various therapeutic approaches have been rapidly developed in recent years, the underlying molecular mechanisms in the pathogenesis of HCC remain enigmatic. The N6-methyladenosine (m6A) RNA modification is believed to regulate RNA metabolism and further gene expression. This process is intricately regulated by multiple regulators, such as methylases and demethylases. Non-coding RNAs (ncRNAs) are involved in the regulation of the epigenetic modification, mRNA transcription and other biological processes, exhibiting crucial roles in tumor occurrence and development. The m6A-ncRNA interaction has been implicated in the malignant phenotypes of HCC and plays an important role in drug resistance. This review summarizes the effect of m6A-ncRNA crosstalk on HCC progression and their clinical implications as prognostic markers and therapeutic targets in this disease.

Methylated lncRNAs suppress apoptosis of gastric cancer stem cells via the lncRNA-miRNA/protein axis

BACKGROUND

Long noncoding RNAs (lncRNAs) play essential roles in the tumorigenesis of gastric cancer. However, the influence of lncRNA methylation on gastric cancer stem cells (GCSCs) remains unclear.

METHODS

The N6-methyladenosine (m6A) levels of lncRNAs in gastric cancer stem cells were detected by methylated RNA immunoprecipitation sequencing (MeRIP-seq), and the results were validated by MeRIP-quantitative polymerase chain reaction (qPCR). Specific sites of m6A modification on lncRNAs were detected by single-base elongation- and ligation-based qPCR amplification (SELECT). By constructing and transfecting the plasmid expressing methyltransferase-like 3 (METTL3) fused with catalytically inactivated Cas13 (dCas13b) and guide RNA targeting specific methylation sites of lncRNAs, we obtained gastric cancer stem cells with site-specific methylation of lncRNAs. Reverse transcription (RT)-qPCR and Western blot were used for detecting the stemness of treated gastric cancer stem cells.

RESULTS

The site-specific methylation of PSMA3-AS1 and MIR22HG suppressed apoptosis and promoted stemness of GCSCs. LncRNA methylation enhanced the stability of PSMA3-AS1 and MIR22HG to suppress apoptosis of GCSCs via the PSMA3-AS1-miR-411-3p- or MIR22HG-miR-24-3p-SERTAD1 axis. Simultaneously, the methylated lncRNAs promoted the interaction between PSMA3-AS1 and the EEF1A1 protein or MIR22HG and the LRPPRC protein, stabilizing the proteins and leading to the suppression of apoptosis. The in vivo data revealed that the methylated PSMA3-AS1 and MIR22HG triggered tumorigenesis of GCSCs.

CONCLUSIONS

Our study revealed the requirement for site-specific methylation of lncRNAs in the tumorigenesis of GCSCs, contributing novel insights into cancer development.

Integrating bioinformatics and experimental validation to unveil disulfidptosis-related lncRNAs as prognostic biomarker and therapeutic target in hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) stands as a prevalent malignancy globally, characterized by significant morbidity and mortality. Despite continuous advancements in the treatment of HCC, the prognosis of patients with this cancer remains unsatisfactory. This study aims at constructing a disulfidoptosis‑related long noncoding RNA (lncRNA) signature to probe the prognosis and personalized treatment of patients with HCC.

METHODS

The data of patients with HCC were extracted from The Cancer Genome Atlas (TCGA) databases. Univariate, multivariate, and least absolute selection operator Cox regression analyses were performed to build a disulfidptosis-related lncRNAs (DRLs) signature. Kaplan-Meier plots were used to evaluate the prognosis of the patients with HCC. Functional enrichment analysis was used to identify key DRLs-associated signaling pathways. Spearman's rank correlation was used to elucidate the association between the DRLs signature and immune microenvironment. The function of TMCC1-AS1 in HCC was validated in two HCC cell lines (HEP3B and HEPG2).

RESULTS

We identified 11 prognostic DRLs from the TCGA dataset, three of which were selected to construct the prognostic signature of DRLs. We found that the survival time of low-risk patients was considerably longer than that of high-risk patients. We further observed that the composition and the function of immune cell subpopulations were significantly different between high- and low-risk groups. Additionally, we identified that sorafenib, 5-Fluorouracil, and doxorubicin displayed better responses in the low-score group than those in the high-score group, based on IC50 values. Finally, we confirmed that inhibition of TMCC1-AS1 impeded the proliferation, migration, and invasion of hepatocellular carcinoma cells.

CONCLUSIONS

The DRL signatures have been shown to be a reliable prognostic and treatment response indicator in HCC patients. TMCC1-AS1 showed potential as a novel prognostic biomarker and therapeutic target for HCC.