[MicroRNA and Lung Cancer: A Mini Review]

A test of miR-128-3p and miR-33a-5p in serum exosome as biomarkers for auxiliary diagnosis of non-small cell lung cancer

Background

Lung cancer is the malignant tumor with the highest incidence and mortality rate in the world today, and non-small cell lung cancer (NSCLC) is its most common type. However, there is still a paucity of specific tumor markers for lung cancer screening. Herein, we detected and compared the levels of miR-128-3p and miR-33a-5p in serum exosomes of NSCLC patients and healthy volunteers, with the aim of identifying suitable exosomal microRNAs (miRNAs) as tumor biomarkers, and explored their value in the auxiliary diagnosis of NSCLC.

Methods

All participants were recruited from September 1, 2022 to December 30, 2022, and met the inclusion criteria. The case group included 20 patients with lung nodules who were highly suspected of having lung cancer (two cases were excluded). A total of 18 healthy volunteers (control group) were also enrolled. Blood samples were collected in both the case group before surgery and in the control group. Quantitative real-time polymerase chain reaction method was used to detect the expression of miR-128-3p and miR-33a-5p in serum exosomes. The main indicators of statistical analysis included the area under the receiver operating characteristic curve (AUC), sensitivity, and specificity.

Results

Compared with the healthy control group, the NSCLC case group had significantly lower expression levels of serum exosome miR-128-3p and miR-33a-5p (P<0.01, P<0.001), and there was a significant positive correlation between the two exosome miRNAs (r=0.848, P<0.01). The AUC values of miR-128-3p alone and miR-33a-5p alone in distinguishing case group and control group were 0.789 [95% confidence interval (CI): 0.637-0.940; sensitivity: 61.1%; specificity: 94.4%; P=0.003] and 0.821 (95% CI: 0.668-0.974; sensitivity: 77.8%; specificity: 83.3%; and P=0.001), respectively. The combination of miR-128-3p and miR-33a-5p had an AUC of 0.855 (95% CI: 0.719-0.991; P<0.001) for distinguishing case group and control group, which was greater than the AUC values of miR-128-3p alone and miR-33a-5p alone (cut-off value: 0.034; sensitivity: 83.3%; and specificity: 88.9%). However, there was no significant difference in the AUC among these three groups (P>0.05).

Conclusions

Serum exosome miR-128-3p and miR-33a-5p showed good performance in NSCLC screening and may be used as new biomarkers for large-scale NSCLC screening.

miRNA-218-5p increases cell sensitivity by inhibiting PRKDC activity in radiation-resistant lung carcinoma cells

BACKGROUND

Non-small cell lung carcinoma (NSCLC) is a malignancy with the highest mortality rate. Currently, surgery combined with radiotherapy is the first choice in the clinical treatment of lung carcinoma (LC); however, long-term radiotherapy leads to radiation resistance in patients, resulting in treatment failure.

METHODS

In this study, a new microRNA-218-5p (miRNA-218-5p) was identified, and its function in LC was investigated.

RESULTS

Reverse transcription quantitative polymerase chain reaction (RT-qPCR) results revealed that miRNA-218-5p was downregulated in LC. Overexpression or inhibition of miRNA-218-5p in LC and targeted binding of protein kinase, DNA-activated, catalytic polypeptide (PRKDC) to miRNA-218-5p were confirmed by comprehensive bioinformatic analysis. Exosomes from A549 and H1299 cells were cocultured with miRNA-218-5p and then cotransfected into radiation-resistant A549R and H1299R cells; the proliferation of radiation-resistant LC cells was found to be effectively inhibited and apoptosis was induced. Overexpression of miRNA-218-5p and X-irradiation could enhance the radiosensitivity of LC cells. Exogenous miRNA-218-5p derived from A549 and H1299 cells could be transfected into radiation-resistant LC cells and could inhibit PRKDC expression, thus accelerating DNA damage, apoptosis, and radiation sensitization of LC cells.

CONCLUSIONS

miRNA-218-5p could induce apoptosis and enhance the radiosensitivity of LC cells through regulatory activities, thus suggesting its application as a potential target for LC treatment.

miRNA-Based Feature Classifier Is Associated with Tumor Mutational Burden in Head and Neck Squamous Cell Carcinoma

Tumor mutation burden (TMB) is considered to be an independent genetic biomarker that can predict the tumor patient's response to immune checkpoint inhibitors (ICIs). Meanwhile, microRNA (miRNA) plays a key role in regulating the anticancer immune response. However, the correlation between miRNA expression patterns and TMB is not elucidated in HNSCC. In the HNSCC cohort of the TCGA dataset, miRNAs that were differentially expressed in high TMB and low TMB samples were screened. The least absolute contraction and selection operator (LASSO) method is used to construct a miRNA-based feature classifier to predict the TMB level in the training set. The test set is used to verify the classifier. The correlation between the miRNA-based classifier index and the expression of three immune checkpoints (PD1, PDL1, and CTLA4) was explored. We further perform functional enrichment analysis on the miRNA contained in the miRNA-based feature classifier. Twenty-five differentially expressed miRNAs are used to build miRNA-based feature classifiers to predict TMB levels. The accuracy of the 25-miRNA-based signature classifier is 0.822 in the training set, 0.702 in the test set, and 0.774 in the total set. The miRNA-based feature classifier index showed a low correlation with PD1 and PDL1, but no correlation with CTLA4. The enrichment analysis of these 25 miRNAs shows that they are involved in many immune-related biological processes and cancer-related pathways. The miRNA expression patterns are related to tumor mutation burden, and miRNA-based feature classifiers can be used as biomarkers to predict TMB levels in HNSCC.