SLC15A1 and breast cancer: As shown in Figure 15, after 4 μg/mL BC administration, the expression levels of claudin-1 and ZO-1 in HCECs were significantly increased and that of PepT1 was significantly decreased (p < 0.01), while these trends were inhibited after BC@HS15/DSPE-PEG2000-L-Val intervention (p < 0.01), indicating that BC upregulated the expression of tight junction proteins and downregulated PepT1 in HCECs, making the penetration and cellular uptake of drugs more difficult, while nanomicelles alleviated the adverse effects of BC, which promoted drug delivery to the deep layers of the cornea.