The mtDNA fragments within exosomes might be novel diagnostic biomarkers of non-small cell lung cancer.

BACKGROUND: A portion of circulating mtDNAs is encapsulated in exosomes, but their contribution to cancers is rarely studied. We aim to investigate the diagnostic potential of exosomal mtDNA content for non-small cell lung cancer (NSCLC). METHODS: Exosomes were isolated from plasma and identified by western blot, scanning electron microscopy, and particle size analysis. The plasma and plasma exosomal mtDNA fragment levels (mtDNA79, mtDNA230, and MTATP8) in healthy, pneumonia, benign lung tumors, and NSCLC were quantified by qPCR. Statistical analyses were performed to compare the levels of mtDNA fragments in different subgroups. ROC analyses were used to evaluate mtDNA fragments' diagnostic sensitivity and specificity. RESULTS: We found that plasma mtDNAs were partially present in exosomes. Both plasma and exosomal mtDNA fragments (mtDNA79, mtDNA230, and MTATP8) were increased in NSCLC, particularly more malignant NSCLC. Compared to plasma mtDNAs and traditional tumor markers, exosomal mtDNAs are more closely associated with aggressive features of NSCLC, like bigger tumor sizes, advanced stages, lymph node metastasis, and distant metastasis, showing higher sensitivity and specificity to diagnose NSCLC. CONCLUSIONS: Changed contents of plasma and plasma exosomal mtDNAs show great potential to diagnose NSCLC, and exosomal mtDNAs might be promising biomarkers for more aggressive NSCLC.

The diagnostic potential of a circRNA-miRNA network in non-small cell lung cancer.

Increasing studies demonstrate the significant contributions of circRNA-related competitive endogenous RNA (ceRNA) regulatory networks to tumorigenesis and cancer progression. Here, we aimed to construct a non-small cell lung cancer (NSCLC)-specific circRNA-miRNA network and evaluate its diagnostic potential in NSCLC. MiRNA deep sequencing was performed to screen differentially-expressed serum miRNAs in NSCLC. Four bioinformatics databases (TargetScan, miRanda, starBase, and RNAhybrid) were used to analyze the integrated circRNA-miRNA interaction network. The circRNA-miRNA network, including hsa-miR-4482-3p, hsa-miR-146a-3p, hsa_circ_0008167 and hsa_circ_0003317 was constructed based on their interactions and preliminary testing in NSCLC cells. The relative levels of the selected non-coding RNAs (ncRNAs) were quantified using quantitative real-time polymerase chain reaction (qRT-PCR) in the healthy, pneumonia, benign lung tumor and NSCLC cohorts. The diagnostic power of the circRNA-miRNA network was evaluated using receiver operating characteristic (ROC) analyses. The serum levels of hsa-miR-4482-3p, hsa-miR-146a-3p, hsa_circ_0008167, and hsa_circ_0003317 were dysregulated in NSCLC. The combination of the four ncRNAs showed the highest diagnostic value to discriminate between benign lung tumors and NSCLC. Additionally, the upregulated levels of hsa_circ_0008167 were correlated to more aggressive features of NSCLC, such as lymph node metastasis, distant metastasis, and higher stage. Furthermore, the combination of hsa_circ_0008167 + hsa-miR-4482-3p, and hsa_circ_0008167 + hsa-miR-4482-3p + hsa-miR-146a-3p had the greatest diagnostic power to differentiate between lymph node +/- metastases and higher/lower stages, respectively, compared to circRNAs or miRNAs alone, and traditional tumor markers. In conclusion, we identified a specific circRNA-miRNA network with higher sensitivity and specificity to diagnose NSCLC, thereby providing a new strategy for further development of ceRNA-related tumor markers in other cancers. KEY MESSAGES: Serum miR-4482-3p, miR-146a-3p, circ_0008167 and circ_0003317 are dysregulated in NSCLC. Higher levels of serum circ_0008167 are associated with more malignant NSCLC. Multiple combinations of circRNAs and miRNAs show higher value to diagnose NSCLC.

PLA2G10 incorporated in exosomes could be diagnostic and prognostic biomarker for non-small cell lung cancer.

BACKGROUND: Exosomal cargos such as nucleic acids and proteins have been attracting major interest as promising diagnostic biomarkers of cancers. The aim of this study was to characterize the mRNA profiles of serum exosomes and to identify non-small cell lung cancer (NSCLC) related mRNAs with higher sensitivity and specificity to diagnose and predict prognosis of NSCLC. METHODS: mRNA microarray analysis was conducted to screen differentially expressed mRNAs in the serum exosomes of NSCLC patients. Selected exosomal mRNA candidate PLA2G10 and PLA2G10 protein were quantified by RT-qPCR and ELISA assay, respectively, in the sample cohorts of healthy, benign lung tumor and NSCLC. Receiver operating characteristic (ROC) analyses were performed to evaluate the diagnostic power of exosomal PLA2G10 mRNA and protein. Kaplan-Meier plots were used to estimate patients' overall and disease-free survival. RESULTS: Serum exosomal PLA2G10 mRNA levels were elevated in NSCLC patients, and were closely related to more aggressive characteristics (higher stages, lymphatic node metastasis and distant metastasis) and poor overall and disease-free survival of NSCLC patients. Intriguingly, PLA2G10 protein was proved to be incorporated in exosomes, and its expression patterns and relationship with clinical pathological factors were similar to exosomal PLA2G10 mRNA. Additionally, the levels of exosomal PLA2G10 mRNA and protein were positively correlated and their combination could improve the diagnostic power to discriminate less and more malignance of NSCLC. CONCLUSIONS: Increased levels of serum exosomal PLA2G10 mRNA and protein were associated with more aggressive features of NSCLC, suggesting their potential as diagnostic and prognostic biomarkers of NSCLC.

Serum exosomal hsa_circ_0069313 has a potential to diagnose more aggressive non-small cell lung cancer.

BACKGROUND: Circular RNAs (circRNAs) derived from exosomes are involved in the carcinogenesis and development of non-small cell lung cancer (NSCLC), showing great potential to be diagnostic biomarkers for NSCLC. METHODS: Serum exosomes were isolated with an exosome isolation kit, and verified by western blot, transmission electron microscopy and a potentiometric analyzer. Five differentially expressed exosomal circRNAs, including hsa_circ_0069313, hsa_circ_0063526, hsa_circ_0010522, hsa_circ_0048677 and hsa_circ_0001946, were selected based on the circRNA array analyses and the published documents in Pubmed. The serum and serum exosomal levels of the above five circRNAs were quantified by qRT-PCR. The diagnostic power of serum and serum exosomal hsa_circ_0069313 was evaluated by receiver operating characteristic (ROC) test. RESULTS: The levels of hsa_circ_0069313 in serum exosomes were statistically lower than those in the matched serum samples. In contrast, the levels of hsa_circ_0063526, hsa_circ_0010522, hsa_circ_0048677 and hsa_circ_0001946 showed no statistical difference in the sera and serum exosomes of healthy donors. The levels of serum and serum exosomal hsa_circ_0069313 were notably elevated in the NSCLC group compared to the healthy, pneumonia and benign lung tumor groups. Furthermore, serum and serum exosomal hsa_circ_0069313 could differ benign lung tumor and NSCLC with AUC values of 0.803 and 0.749, respectively. Intriguingly, the higher levels of serum exosomal hsa_circ_0069313 were associated with stage III-IV, lymph node metastasis and distant metastasis of NSCLC. CONCLUSIONS: Serum and serum exosomal hsa_circ_0069313 have the potential to discriminate NSCLC and benign lung tumor. The higher levels of serum exosomal hsa_circ_0069313 are linked to more aggressive pathological features of NSCLC.

Evaluation of EpCAM-specific exosomal lncRNAs as potential diagnostic biomarkers for lung cancer using droplet digital PCR.

Accumulating evidence demonstrated that long non-coding RNAs (lncRNAs) derived from exosomes had the potential to be diagnostic markers for lung cancer. However, the diagnostic value of lncRNAs from epithelial cell adhesion molecule (EpCAM)-positive exosomes remains unclear. In the study, serum EpCAM-positive exosomes were isolated with magnetic beads, and their role in lung cancer was investigated in vitro and in vivo. The copy numbers of lncRNAs RP11-77G23.5 and PHEX-AS1 in EpCAM-specific exosomes were quantified by droplet digital PCR (ddPCR). The diagnostic value of RP11-77G23.5 and PHEX-AS1 was tested in the training cohort and verified in the validation cohort. We found that EpCAM-specific exosomes could promote lung cancer development in vitro and in vivo. RP11-77G23.5 and PHEX-AS1 were significantly elevated in EpCAM-specific exosomes from lung cancer patients and could distinguish malignant from benign lung tumors. The amounts of RP11-77G23.5 were statistically higher in the subtype of lung adenocarcinoma (LUAC) than that of lung squamous cell carcinoma (LUSC), showing its capability to subtype LUAC and LUSC, while PHEX-AS1 exhibited distinct expression signatures between lower and higher tumor stages, and without and with distant metastasis, indicating its association with lung cancer progression. In conclusion, the EpCAM-specific exosomal lncRNAs RP11-77G23.5 and PHEX-AS1 may be promising diagnostic biomarkers for lung cancer. KEY MESSAGES: Serum EpCAM-positive exosomes promote lung cancer development in vitro and in vivo. Two EpCAM-specific exosomal lncRNAs can be simultaneously detected by RT-ddPCR. EpCAM-specific exosomal RP11-77G23.5 has the potential to subtype LUAC and LUSC. EpCAM-specific exosomal PHEX-AS1 is associated with lung cancer progression.