Epidemiologic studies have shown an association between tuberculosis and lung cancer. The altered tumor microenvironment after tuberculosis infection appears to contribute to cancer progression. Pleural effusions are enriched in exosomes, which act as mediators of intercellular communication. We hypothesized that tuberculous pleural effusion (TPE)-derived exosomes mediate intercellular communication. Then, we examined the interaction between TPE-derived exosomes and cancer cells. Exosomal miRNA profiling of TPE was performed using a microRNA array. An in vitro lung cancer cell experiment and an in vivo mouse xenograft tumor model were used to evaluate the effects of the selected exosomal microRNAs. TPE-derived exosome treatment enhanced the growth of A549 cells both in vitro and in a nude mouse xenograft model. Neighboring cancer cells were observed to take up TPE-derived exosomes, which promoted cancer cell invasion. Exosome-mediated transfer of the selected microRNAs, including miR-130b-3p and miR-423-5p, to A549 lung cancer cells activated cyclin D1 signaling and increased the expression of phosphorylated p65, a cyclin D1 transcription factor. Inhibitors of miR-130b and miR-423-5p suppressed the promotion of lung cancer by TPE-derived exosomes and reduced the expression of p65 and cyclin D1. These results suggest that TPE-derived exosomal miRNAs can serve as a novel therapeutic target in tuberculous fibrosis-induced lung cancer.
Keywords: exosome; intercellular communication; lung cancer; tuberculosis.