Establishment and assessment of an oral squamous cell carcinoma N7-methylguanosine methyltransferase associated microRNA prognostic model

Abstract

Background: N7-methylguanosine (m7G) methyltransferases and microRNAs (miRNAs) are closely associated with tumor progression. However, the role of m7G methyltransferase-related miRNAs as prognostic markers in oral squamous cell carcinoma (OSCC) has not been studied. This study aimed to explore the m7G methyltransferase-related miRNAs in OSCC, establish a prognostic model based on m7G methyltransferase-related miRNAs, investigate their correlation with immune cell infiltration, and assess their potential prognostic value. Methods: Transcriptional and clinical data of patients with OSCC were obtained from The Cancer Genome Atlas (TCGA) database. TargetScan and miRWalk were used to predict m7G methyltransferase-related miRNAs. Subsequently, differentially expressed m7G methyltransferase-related miRNAs in TCGA-OSCC were selected. Cox and least absolute shrinkage and selection operator (LASSO) regression analyses were used to build an m7G methyltransferase-related miRNA risk prognostic model for TCGA-OSCC. Patients were stratified into high- and low-risk groups. The predictive and diagnostic accuracies of the risk prognostic model were further validated using Kaplan-Meier survival analysis, receiver operating characteristic (ROC) curve analysis, independent prognosis analysis, and nomogram plots. Finally, quantitative real-time polymerase chain reaction (qPCR) was used to validate the expression levels of m7G methyltransferase-related miRNAs in postoperative cancer and adjacent normal tissues from 60 patients with OSCC. Results: Through Cox and LASSO regression analysis, six candidate miRNAs (hsa-miR-338-3p, hsa-miR-1251-3p, hsa-miR-3129-5p, hsa-miR-4633-3p, hsa-miR-216a-3p, and hsa-miR-6503-3p) most relevant to the prognosis of patients with OSCC were identified to construct an m7G methyltransferase-related miRNA risk prognostic model. In this model, the overall survival (OS) of the high-risk group was significantly shorter than that of the low-risk group (P < 0.001). The model effectively predicted prognosis and served as an independent prognostic indicator for patients with OSCC. Compared with the low-risk group, the high-risk group exhibited a significantly increased capacity for immune cell infiltration (P < 0.05), while the activation and initiation abilities of immune cells were decreased. Finally, six m7G methyltransferase-related miRNAs were validated in OSCC tissue samples. Conclusion: The risk prognostic model based on six m7G methyltransferase-related miRNAs can predict the OS rate of patients with OSCC and has the potential to guide individualized treatment. This prognostic model is closely associated with immune cell infiltration in patients with OSCC.

Keywords: N7-methylguanosine methyltransferase; immune microenvironment; microRNA; oral squamous cell carcinoma; prognosis.

Figure 1

Expression and regulatory network analysis of m7G methyltransferase complex METTL1/WDR4 mRNA and associated miRNAs in TCGA-OSCC. (A, B) METTL1 and WDR4 expression levels in the TCGA-OSCC cohort. (C) Correlation evaluation of expression between WDR4 and METTL1. (D) Prediction scores of miRNAs binding to METTL1 and WDR4 mRNA using TargetScan and miRWalk online databases (Venn diagram). (E) Volcano plot depicting differential expressed m7G methyltransferase-associated miRNAs between normal and tumor tissues in the TCGA-OSCC cohort. (F) Co-expression network of miRNA-m7G-associated genes.

Figure 2

Enrichment analysis of 56 m7G methyltransferase-associated miRNAs. (A) Biological processes, (B) cellular components, (C) molecular functions, and (D) biological pathways of m7G methyltransferase-associated miRNAs.

Figure 3

Establishment of the m7G methyltransferase-associated miRNA prognostic model. (A) Univariate Cox regression analysis of six m7G methyltransferase-associated miRNAs shown in a forest plot. (B) LASSO regression analysis. (C) Cross-validation. (D) Prediction results of binding sites at the 3'UTR of METTL1 and WDR4 mRNA for six miRNAs.

Figure 4

Prognostic model for m7G methyltransferase-associated miRNAs constructed based on TCGA-OSCC patient data. (A) Risk value distribution and Kaplan-Meier survival curve for the training set. (B) Risk value distribution and Kaplan-Meier survival curve for the testing set. (C) Risk value distribution and Kaplan-Meier survival curve for the entire TCGA sample.

Figure 5

Accuracy of the constructed m7G methyltransferase-associated miRNA prognostic model in predicting survival rates for patients with OSCC. (A) Principal component analysis of TCGA whole-sample data. (B) Time-reliant ROC curve for the training set. (C) Time-reliant ROC curve for the testing set. (D) Time-reliant ROC curve for the complete TCGA sample. (E) Concordance index analysis comparing risk scores with clinical variables such as age, sex, tumor grade, and TNM stage.

Figure 6

Construction of a nomogram. (A, B) Forest plots showing results of univariate and multivariate regression analyses for risk scores. (C) Nomogram combining risk values from the prognostic model with patient TNM staging. (D) Calibration curve for the nomogram. (E-G) ROC curves of the nomogram for predicting survival at 1, 3 and 5 years.

Figure 7

Immune infiltration and tumor microenvironment in high- and low-risk OSCC groups. (A) Comparison of immune levels between high- and low-risk groups. (B) Comparison of infiltration levels for 23 resistant cell types within high- and low-risk groups. (C) Comparison of elevated values for 13 resistance-associated pathways within high- and low-risk groups. (D) Comparison of resistant gene expression levels between high- and low-risk groups. (E) Assessment of anti-cancer-immune activity in the cancer-immunity cycle for patients with OSCC in the high- and low-risk groups.

Figure 8

Pathway enrichment investigation and chemotherapy drug sensitivity analysis within high- and low-risk groups. (A, B) Pathway enrichment analysis results within high- and low-risk groups. (C, D) IC₅₀ values of phenformin and AMG-706 for the two risk groups.

Figure 9

Expression levels of six candidate miRNAs associated with m7G methyltransferase genes in OSCC tissues. (A-F) Relative expression levels of six miRNAs were assessed using qPCR within 60 pairs of OSCC tissues and adjacent normal tissues.