Drug monomers from Salvia miltiorrhiza Bge. promoting tight junction protein expression for therapeutic effects on lung cancer.

Salvia miltiorrhiza Bge. is a traditional Chinese medicine (TCM) that has been used for treatment of various diseases, including cancer by activating blood circulation and removing blood stasis. Tanshinone (TanIIA) and cryptotanshinone (CPT) are major lipophilic compounds extracted from the root of Salvia miltiorrhiza Bge., which are considered to be the effective compounds affecting the efficacy of the anti-tumor therapy of Salvia miltiorrhiza Bge. We have explored the mechanism of CPT and TanIIA exerting inhibition in non-small cell lung cancer (NSCLC) to provide experimental data support for guiding the translational development and clinical application of anti-tumor components of TCM. The subcutaneous tumor model and in vitro culture model of A549 cells was constructed to evaluate CPT and TanIIA's tumour-inhibitory effect respectively. RNA sequencing (RNA-seq) and bioinformatics analysis were conducted to identify differentially expressed genes (DEGs) and signalling pathways related to CPT and TanIIA treatment. qRT-PCR and Western blot were used to explore the mechanism of CPT and TanIIA intervention on NSCLC. Both CPT and TanIIA significantly inhibited the proliferation of A549 tumor cells and tumor growth in animal models. After intervention, the migration ability decreased and the level of apoptosis increased. RNA-seq results showed that both CPT and TanIIA could cause gene differential expression, miR-21-5p as one of the most significant gene expression differences between the two groups, and could act on cell connectivity. CPT and TanIIA play a regulatory role in regulating tight junction proteins (Occludin and ZO1), and Occludin mRNA and protein levels were reduced in an in vitro miR-21-5p overexpression A549 cell model. The mechanisms may be related to the reduction of miR-21-5p expression to increase the level of promoted tight junction protein expression for the purpose of inhibiting proliferation and invasion of NSCLC.