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.