CLDN1 and small cell lung carcinoma: In this regard, Mao et al. [135] found that exosomes from miR-375-3p-transfected SCLC cells disrupt tight junctions in vascular endothelial cells by inhibiting the claudin-1 protein, breaking vascular barriers, increasing permeability, and promoting the transendothelial migration of SCLC cells in vitro.