Jianpi Yangzheng decoction suppresses gastric cancer progression via modulating the miR-448/CLDN18.2 mediated YAP/TAZ signaling

Abstract

Ethnopharmacological relevance: Developing complementary and effective drugs with less toxicity is urgent for gastric cancer (GC) therapy. Jianpi Yangzheng Decoction (JPYZ) is a curative medical plants formula against GC in clinic while its molecular mechanism remains to be further elucidated.

Aim of the study: To evaluate the in vitro and in vivo anticancer efficacy of JPYZ against GC and its potential mechanisms.

Materials and methods: The effect of JPYZ on regulating the candidate targets were screened and examined by RNA-Seq, qRT-PCR, luciferase reporter assay, and immunoblotting. Rescue experiment was conducted to authenticate the regulation of JPYZ on the target gene. Molecular interaction, intracellular localization and function of target genes were elucidated via Co-IP and cytoplasmic-nuclear fractionation. The impact of JPYZ on the abundance of target gene in clinical specimens of GC patients was evaluated by IHC.

Results: JPYZ treatment suppressed the proliferation and metastasis of GC cells. RNA seq revealed JPYZ significantly downregulated miR-448. A reporter plasmid containing CLDN18 3'-UTR WT exhibited significant decrease in luciferase activity when co-transfected with miR-448 mimic in GC cells. CLDN18.2 deficiency promoted the proliferation and metastasis of GC cells in vitro, as well as intensified the growth of GC xenograft in mice. JPYZ reduced the proliferation and metastasis of GC cells with CLDN18.2 abrogation. Mechanically, suppressed activities of transcriptional coactivator YAP/TAZ and its downstream targets were observed in GC cells with CLDN18.2 overexpression and those under JPYZ treatment, leading to cytoplasmic retention of phosphorylated YAP at site Ser-127. High abundance of CLDN18.2 was detected in more GC patients who received chemotherapy combined with JPYZ.

Conclusion: JPYZ has an inhibitory effect on GC growth and metastasis partly by elevating CLDN18.2 abundance in GC cells, indicating more patients may benefit from combination therapy of JPYZ and the upcoming CLDN18.2 target agents.

Keywords: Claudin 18.2; Gastric cancer; Traditional Chinese medicine; YAP/TAZ.