The essential roles of m6A RNA modification to stimulate ENO1-dependent glycolysis and tumorigenesis in lung adenocarcinoma

RNA Epigenetics in Chronic Lung Diseases

Chronic lung diseases are highly prevalent worldwide and cause significant mortality. Lung cancer is the end stage of many chronic lung diseases. RNA epigenetics can dynamically modulate gene expression and decide cell fate. Recently, studies have confirmed that RNA epigenetics plays a crucial role in the developing of chronic lung diseases. Further exploration of the underlying mechanisms of RNA epigenetics in chronic lung diseases, including lung cancer, may lead to a better understanding of the diseases and promote the development of new biomarkers and therapeutic strategies. This article reviews basic information on RNA modifications, including N⁶ methylation of adenosine (m⁶A), N¹ methylation of adenosine (m¹A), N⁷-methylguanosine (m⁷G), 5-methylcytosine (m⁵C), 2'O-methylation (2'-O-Me or Nm), pseudouridine (5-ribosyl uracil or Ψ), and adenosine to inosine RNA editing (A-to-I editing). We then show how they relate to different types of lung disease. This paper hopes to summarize the mechanisms of RNA modification in chronic lung disease and finds a new way to develop early diagnosis and treatment of chronic lung disease.

Expression patterns of platinum resistance-related genes in lung adenocarcinoma and related clinical value models

The purpose of this study was to explore platinum resistance-related biomarkers and mechanisms in lung adenocarcinoma. Through the analysis of gene expression data of lung adenocarcinoma patients and normal patients from The Cancer Genome Atlas, Gene Expression Omnibus database, and A database of genes related to platinum resistance, platinum resistance genes in lung adenocarcinoma and platinum resistance-related differentially expressed genes were obtained. After screening by a statistical significance threshold, a total of 252 genes were defined as platinum resistance genes with significant differential expression, of which 161 were up-regulated and 91 were down-regulated. The enrichment results of up-regulated gene Gene Ontology (GO) showed that TOP3 entries related to biological processes (BP) were double-strand break repair, DNA recombination, DNA replication, the down-regulated gene GO enriches the TOP3 items about biological processes (BP) as a response to lipopolysaccharide, muscle cell proliferation, response to molecule of bacterial origin. Gene Set Enrichment Analysis showed that the top three were e2f targets, g2m checkpoint, and rgf beta signaling. A prognostic model based on non-negative matrix factorization classification showed the characteristics of high- and low-risk groups. The prognostic model established by least absolute shrinkage and selection operator regression and risk factor analysis showed that genes such as HOXB7, NT5E, and KRT18 were positively correlated with risk score. By analyzing the differences in m6A regulatory factors between high- and low-risk groups, it was found that FTO, GPM6A, METTL3, and YTHDC2 were higher in the low-risk group, while HNRNPA2B1, HNRNPC, TGF2BP1, IGF2BP2, IGF2BP3, and RBM15B were higher in the high-risk group. Immune infiltration and drug sensitivity analysis also showed the gene characteristics of the platinum-resistant population in lung adenocarcinoma. ceRNA analysis showed that has-miR-374a-5p and RP6-24A23.7 were lower in the tumor expression group, and that the survival of the low expression group was worse than that of the high expression group. In conclusion, the results of this study show that platinum resistance-related differentially expressed genes in lung adenocarcinoma are mainly concentrated in biological processes such as DNA recombination and response to lipopolysaccharide. The validation set proved that the high-risk group of our prognostic model had poor survival. M6A regulatory factor analysis, immune infiltration, and drug sensitivity analysis all showed differences between high and low-risk groups. ceRNA analysis showed that has-miR-374a-5p and RP6-24A23.7 could be protective factors. Further exploration of the potential impact of these genes on the risk and prognosis of drug-resistant patients with lung adenocarcinoma would provide theoretical support for future research.

ALKBH5 in mouse testicular Sertoli cells regulates Cdh2 mRNA translation to maintain blood-testis barrier integrity

BACKGROUND

RNA N⁶-methyladenosine (m⁶A) is involved in mammalian spermatogenesis. In both germ cells and Leydig cells, ALKBH5 regulates spermatogenesis and androgen synthesis in an m⁶A-dependent manner. However, it is unclear whether ALKBH5 plays a role in testicular Sertoli cells, which constitute the blood-testis barrier (BTB) through cell junctions between adjacent Sertoli cells.

METHODS

ALKBH5 expression in the testes of humans and mice was detected by immunohistochemical staining and immunofluorescence staining. BTB integrity was evaluated by BTB assay. m⁶A-seq was performed to screen for BTB-related molecules regulated by ALKBH5. m⁶A immunoprecipitation-quantitative real-time polymerase chain reaction (qPCR), RNA immunoprecipitation-qPCR, western blot, coimmunoprecipitation, and polysome fractionation-qPCR analyses were performed to explore the mechanisms of ALKBH5 in BTB. Transmission electron microscopy was applied to observe the BTB ultrastructure.

RESULTS

ALKBH5 in Sertoli cells is related to the integrity of the BTB. Subsequently, the m⁶A level on Cdh2 mRNA, encoding a structural protein N-cadherin in the BTB, was found to be regulated by ALKBH5. IGF2BP1/2/3 complexes and YTHDF1 promoted Cdh2 mRNA translation. In addition, we found that basal endoplasmic specialization, in which N-cadherin is a main structural protein, was severely disordered in the testes of Alkbh5-knockout mice.

CONCLUSIONS

Our study revealed that ALKBH5 regulates BTB integrity via basal endoplasmic specialization by affecting Cdh2 mRNA translation.

RNA m6 A methylation in cancer

N⁶ -methyladenosine (m⁶ A) is one of the most abundant internal modifications in eukaryotic messenger RNAs (mRNAs) and non-coding RNAs (ncRNAs). It is a reversible and dynamic RNA modification that has been observed in both internal coding segments and untranslated regions. Studies indicate that m⁶ A modifications play important roles in translation, RNA splicing, export, degradation and ncRNA processing control. In this review, we focus on the profiles and biological functions of RNA m⁶ A methylation on both mRNAs and ncRNAs. The dynamic modification of m⁶ A and its potential roles in cancer development are discussed. Moreover, we discuss the possibility of m⁶ A modifications serving as potential biomarkers for cancer diagnosis and targets for therapy.

A novel algorithm for lung adenocarcinoma based on N6 methyladenosine-related immune long noncoding RNAs as a reliable biomarker for predicting survival outcomes and selecting sensitive anti-tumor therapies

Background

Lung cancer is a highly heterogeneous malignant tumor with high incidence and mortality. Recently, increasing evidence has demonstrated that N6‐methyladenosine (m6A) methylation and the tumor microenvironment (TME) play important roles in the occurrence and development of lung adenocarcinoma (LUAD).

Methods

In this study, we constructed a novel and reliable algorithm based on m6A‐related immune lncRNAs (mrilncRNAs), consisting of molecular subtypes and a prognostic signature.

Results

According to the analyses of molecular subtypes, patients in cluster 1 were in a more advanced stage, showed poor prognosis, were sensitive to immunotherapy (anti‐programmed cell death 1 Ligand 1 (PD‐L1) and anti‐lymphocyte activating 3 (LAG‐3)), and had a highest tumor mutational burden (TMB), while anti‐cytotoxic T‐lymphocyte‐associated protein 4 (CTLA‐4) therapy seemed to be a good choice for patients in cluster 3. Subsequently, the results of the risk assessment model indicated that the low‐risk patients exhibited a survival advantage, had an earlier stage, and showed a higher response to common anti‐cancer drugs, including chemotherapy (Docetaxel, Paclitaxel), molecular targeted therapy (Erlotinib), and immunotherapy (anti‐CTLA‐4 therapy), while Gefitinib could be a good choice for patients with high‐risk scores.

Conclusion

In conclusion, the constructed algorithm exhibits promising practical prospects, and allows the selection of suitable and sensitive anti‐cancer drugs, which could provide theoretical support to predict the survival outcomes of patients with LUAD.