Exosomal epidermal growth factor receptor is involved in HPV-16 E7-induced epithelial-mesenchymal transition of non-small cell lung cancer cells: A driver of signaling in vivo

Our previous studies have demonstrated that human papillomavirus (HPV)-16 E7 oncoprotein promoted epithelial-mesenchymal transition (EMT) in non-small cell lung cancer (NSCLC) cells. Moreover, recent studies have found that exosomes can mediate EMT of NSCLC cells and epidermal growth factor receptor (EGFR) is related to the progression of NSCLC. Here, we further investigated the role of exosomal EGFR in HPV-16 E7-induced EMT of NSCLC cells. Our results showed that the exosomes derived from the stable HPV-16 E7-overexpressing A549 and NCI-H460 NSCLC cells (E7 Exo) significantly increased migration, invasion, and proliferation abilities of NSCLC cells as compared with the exosomes derived from empty vector-infected NSCLC cells (ev Exo). Moreover, both in vitro and in vivo results demonstrated that E7 Exo dramatically enhanced EMT of NSCLC cells and promoted the growth of subcutaneous NSCLC xenografts. Additionally, HPV-16 E7 enhanced the expression of EGFR and p-EGFR in both NSCLC cells and exosomes. Furthermore, the inhibition of EGFR activation or exosome secretion suppressed E7 Exo-induced migration, invasion, and EMT of NSCLC. Moreover, 12 kinds of differentially expressed miRNAs between E7 Exo and ev Exo (fold change≥2, P ≤ .05) were screened out, of which 7 miRNAs were up-regulated while 5 miRNAs were down-regulated in A549 E7 Exo. Taken together, our findings suggest that exosomal EGFR is involved in HPV-16 E7-induced EMT of NSCLC cells, which may play a key role in the progression of HPV-related NSCLC.