Lower SLC7A2 expression is associated with enhanced multidrug resistance, less immune infiltrates and worse prognosis of NSCLC.

Background: Solute carrier family 7 member 2 (SLC7A2), a cationic amino acid transporter, is lowly expressed in ovarian and hepatocellular cancers, which is associated with their worse prognosis. However, its roles in the prognosis, drug resistance and immune infiltration in non-small-cell lung cancer (NSCLC) are unclear.

Methods: We chose SLC7A2 from RNA-Seq of paclitaxel/cisplatin-resistant A549 cells, then bioinformatics, cell lines construction, RT-qPCR, and CCK8 were performed to investigate SLC7A2 role.

Result: We analyzed the 223 differentially expressed genes (DEGs) from RNA-Seq of paclitaxel/cisplatin-resistant A549 cells and found that SLC7A2 expression was down-regulated in NSCLC. Lower SLC7A2 expression was associated with worse recurrence-free survival (RFS) in NSCLC. SLC7A2 silencing enhanced the proliferation of NSCLC cells and their insensitivity to paclitaxel, cisplatin, and gemcitabine in vitro. Activation of AMPK has up-regulated SLC7A2 expression and enhanced the sensitivity of NSCLC cells to anti-tumor drugs, which could be attributed to E2F1's regulation. In addition, the levels of SLC7A2 expression were correlated to the numbers of infiltrated neutrophils, macrophages, dendritic cells and their marker genes, like CD86, HLA-DPA1 and ITGAM.

Conclusions: SLC7A2 may act as a tumor suppressor to modulate drug sensitivity, immune infiltration and survival in NSCLC. Video abstract.